WO2015098937A1 - Overvoltage protection circuit and power conversion device provided therewith - Google Patents

Overvoltage protection circuit and power conversion device provided therewith Download PDF

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Publication number
WO2015098937A1
WO2015098937A1 PCT/JP2014/084101 JP2014084101W WO2015098937A1 WO 2015098937 A1 WO2015098937 A1 WO 2015098937A1 JP 2014084101 W JP2014084101 W JP 2014084101W WO 2015098937 A1 WO2015098937 A1 WO 2015098937A1
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WIPO (PCT)
Prior art keywords
voltage
circuit
impedance
switch
overvoltage protection
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PCT/JP2014/084101
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French (fr)
Japanese (ja)
Inventor
俊彰 佐藤
矢吹　俊生
田口　泰貴
淳也 三井
康平 森田
敬之 畑山
Original Assignee
ダイキン工業株式会社
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Application filed by ダイキン工業株式会社 filed Critical ダイキン工業株式会社
Priority to CN201480070190.2A priority Critical patent/CN105874673B/en
Publication of WO2015098937A1 publication Critical patent/WO2015098937A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/20—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage

Definitions

  • the present invention relates to an overvoltage protection circuit and a power conversion device including the same.
  • an overvoltage protection circuit as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2009-207329) is provided. This overvoltage protection circuit is configured to shut off the power supply with a relay when the voltage is equal to or higher than a predetermined voltage.
  • the time required for the power supply voltage to become excessive is extremely short, and it is difficult to reliably protect with a slow response due to the interruption by the relay.
  • a semiconductor element such as a semiconductor element that has a short time to withstand overvoltage cannot be protected by being interrupted by a relay.
  • increasing the breakdown voltage of a semiconductor element or the like only for an instantaneous excessive voltage leads to an increase in cost and size.
  • an object of the present invention is to provide a small-sized and low-cost overvoltage protection circuit that protects a device from a momentary excessive voltage, and a power conversion device including the same.
  • An overvoltage protection circuit is an overvoltage protection circuit connected between a power source and a device supplied with power from the power source, and includes an impedance circuit, a voltage detector, a bypass circuit, It has.
  • the impedance circuit is connected in series with the device on a power line connecting the power source and the device.
  • the voltage detector detects the voltage of the power supply.
  • the bypass circuit is a circuit that bypasses the impedance circuit.
  • the bypass circuit has a switch for opening and closing the bypass circuit. The switch normally closes the bypass circuit, and shuts off the bypass circuit when the value detected by the voltage detector exceeds a predetermined threshold value.
  • the overvoltage protection circuit according to the second aspect of the present invention is the overvoltage protection circuit according to the first aspect, and further includes a second switch for opening and closing the power supply line.
  • the second switch normally turns on the power supply line, and shuts off the power supply line after operation of the switch when the value detected by the voltage detector exceeds a predetermined threshold.
  • the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage.
  • the second switch is operated to cut off the power line, thereby stopping the power consumption in the impedance circuit.
  • impedance overheating can be suppressed and the power rating can be reduced.
  • the overvoltage protection circuit according to the third aspect of the present invention is the overvoltage protection circuit according to the first aspect, and further includes a second switch for opening and closing the power supply line.
  • the second switch normally turns on the power supply line, and when the time when the value detected by the voltage detector exceeds a predetermined threshold becomes longer than the predetermined duration determination value, Shut off the line.
  • the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage.
  • the second switch is operated to cut off the power line, thereby stopping the power consumption in the impedance circuit.
  • impedance overheating can be suppressed and the power rating can be reduced.
  • An overvoltage protection circuit is the overvoltage protection circuit according to the first aspect, further comprising: a second switch that opens and closes a power supply line; and a device voltage detector that detects a voltage applied to the device. I have.
  • the second switch normally turns on the power line, and shuts off the power line after the operation of the switch when the value detected by the device voltage detector exceeds a predetermined third threshold.
  • the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage.
  • the second switch is operated to cut off the power line, thereby stopping the power consumption in the impedance circuit.
  • impedance overheating can be suppressed and the power rating can be reduced.
  • An overvoltage protection circuit is an overvoltage protection circuit connected between a power supply and a device supplied with power from the power supply, and includes a variable impedance circuit and a voltage detector. .
  • the variable impedance circuit is connected in series with the device on a power line connecting the power source and the device.
  • the voltage detector detects the voltage of the power supply. Further, the variable impedance circuit makes the impedance value larger than the normal value when the value detected by the voltage detector exceeds a predetermined threshold value.
  • the impedance value is normally set to a small value (including 0), so the power consumption in the variable impedance circuit is suppressed, the voltage drop in the variable impedance circuit is small, and the application to the device It can also be suppressed that the voltage is lowered by the voltage drop in the variable impedance circuit.
  • the impedance value is set to a large value during overvoltage, the voltage applied to the device is reduced by the voltage drop in the variable impedance circuit, and the device can be protected from overvoltage.
  • the overvoltage protection circuit according to the sixth aspect of the present invention is the overvoltage protection circuit according to the fifth aspect, and the variable impedance circuit continuously changes the impedance value according to the change in the detection value by the voltage detector.
  • the impedance value is set to a large value at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop in the variable impedance circuit, and the device can be protected from the overvoltage.
  • the overvoltage protection circuit according to the seventh aspect of the present invention is the overvoltage protection circuit according to the fifth aspect, and the variable impedance circuit changes the impedance value stepwise in accordance with the change of the detection value by the voltage detector.
  • the impedance value is set to a large value at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop in the variable impedance circuit, and the device can be protected from the overvoltage.
  • the overvoltage protection circuit according to the eighth aspect of the present invention is the overvoltage protection circuit according to the fifth aspect, and the variable impedance circuit selectively uses a plurality of impedance elements.
  • the plurality of impedance elements includes a first impedance element and a second impedance element.
  • the first impedance element has a first impedance value.
  • the second impedance element has a second impedance value that is greater than the first impedance value.
  • the variable impedance circuit switches the impedance element to be used from the first impedance element to the second impedance element when the value detected by the voltage detector exceeds a predetermined threshold value when the first impedance element is used.
  • the overvoltage protection circuit according to the ninth aspect of the present invention is the overvoltage protection circuit according to any one of the fifth to eighth aspects, and further includes a second switch that opens and closes the power supply line.
  • the second switch normally turns on the power supply line, and shuts off the power supply line when the value detected by the voltage detector exceeds a predetermined second threshold.
  • the overvoltage protection circuit according to the tenth aspect of the present invention is the overvoltage protection circuit according to any one of the fifth to eighth aspects, and further includes a second switch that opens and closes the power supply line.
  • the second switch normally turns on the power line, and shuts off the power line when the time when the value detected by the voltage detector exceeds a predetermined threshold becomes longer than a predetermined duration determination value. .
  • An overvoltage protection circuit is the overvoltage protection circuit according to any one of the fifth to eighth aspects, the second switch for opening and closing the power supply line, and the voltage applied to the device And a device voltage detector.
  • the second switch normally turns on the power line, and shuts off the power line when the value detected by the device voltage detector exceeds a predetermined third threshold.
  • the overvoltage protection circuit according to the twelfth aspect of the present invention is the overvoltage protection circuit according to any one of the first to eleventh aspects, and the power supply is an AC power supply.
  • the overvoltage protection circuit according to the thirteenth aspect of the present invention is the overvoltage protection circuit according to any one of the first to eleventh aspects, and the power source is a DC power source.
  • the switch for turning on and off the alternating current needs bidirectionality, but the switch arranged on the downstream side of the DC power supply may be a one-way switch, so that the cost of the switch can be reduced.
  • the power conversion device includes a converter circuit, an inverter circuit, and any one of the overvoltage protection circuits according to the first to tenth aspects.
  • the converter circuit is connected to an AC power source and converts an AC voltage into a DC voltage.
  • the inverter circuit converts a DC voltage into an AC voltage.
  • the overvoltage protection circuit can protect the converter circuit from excessively applied alternating voltage or the inverter circuit from transiently applied excessive DC voltage.
  • the bypass circuit since the bypass circuit is normally closed, power is not consumed by the impedance circuit, and the voltage applied to the device is lowered by the voltage drop at the impedance. It can also be avoided. On the other hand, at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop of the impedance of the impedance circuit, and the device can be protected from overvoltage.
  • the bypass circuit since the bypass circuit is normally closed, power is not consumed in the impedance circuit, and the voltage applied to the device is only the voltage drop in the impedance circuit. Lowering can also be avoided.
  • the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage.
  • the second switch is operated to cut off the power line, thereby stopping the power consumption in the impedance circuit.
  • impedance overheating can be suppressed and the power rating can be reduced.
  • the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage. Further, after the switch is operated, the second switch is operated to cut off the power supply line, thereby stopping the power consumption in the impedance circuit. As a result, the power rating of the impedance can be reduced.
  • the impedance value is normally set to a small value (including 0)
  • the power consumption in the impedance circuit is suppressed, and the voltage drop in the impedance circuit is also small. It is also possible to suppress the voltage applied to the device from being lowered by the voltage drop in the impedance circuit.
  • the impedance value is set to a large value during overvoltage, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage.
  • the impedance value is set to a large value at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, Equipment can be protected from overvoltage.
  • the overvoltage protection circuit since it is normally connected to the first impedance element having the smaller impedance value, the power consumption in the impedance circuit is suppressed, and the voltage drop in the impedance circuit is also small. It is also possible to suppress the voltage applied to the device from being lowered by the voltage drop in the impedance circuit.
  • the power consumption in the impedance circuit is stopped by operating the second switch to cut off the power line.
  • impedance overheating can be suppressed and the power rating can be reduced.
  • the overvoltage protection circuit In the overvoltage protection circuit according to the twelfth aspect of the present invention, even if the supply voltage from the AC power supply is an excessive voltage, the voltage applied to the device is reduced by the voltage drop in the impedance circuit. Therefore, it is not necessary to design the equipment with a high voltage rating only for protection from an excessive voltage for a short time, which is reasonable.
  • the switch for turning on and off the alternating current needs bidirectionality, but the switch arranged on the downstream side of the DC power supply may be a one-way switch, so that the low cost of the switch Can be achieved.
  • the overvoltage protection circuit protects the converter circuit from excessively applied alternating voltage or protects the inverter circuit from transiently applied excessive DC voltage. be able to.
  • the graph which shows the change of the voltage V when an impedance contains an inductance component.
  • the circuit diagram of the power converter device provided with the overvoltage protection circuit which concerns on 3rd Embodiment of this invention.
  • the graph which shows the change of the voltage V when an impedance is only resistance The graph which shows the change of the voltage V when an impedance is only resistance.
  • the circuit diagram of the power converter device provided with the overvoltage protection circuit which concerns on another modification.
  • the circuit diagram of the apparatus provided with the overvoltage protection circuit which concerns on 5th Embodiment of this invention.
  • the graph which shows the change of the voltage V when an impedance is only a variable resistance and an impedance increases continuously.
  • the graph which shows the change of the voltage V when an impedance is only a variable resistance and an impedance increases in steps.
  • the circuit diagram of the apparatus provided with the overvoltage protection circuit which concerns on 6th Embodiment of this invention.
  • the graph which shows the change of the voltage V when an impedance is only resistance The circuit diagram of the power converter device provided with the overvoltage protection circuit which concerns on another modification.
  • the circuit diagram of the apparatus provided with the overvoltage protection circuit which concerns on 5th Embodiment of this invention.
  • the circuit diagram of the power converter device provided with the overvoltage protection circuit which concerns on 9th Embodiment of this invention.
  • FIG. 1 is a circuit diagram of a device including an overvoltage protection circuit 50 according to the first embodiment of the present invention.
  • the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902.
  • the overvoltage protection circuit 50 is connected between the commercial power supply 90 and the device 30.
  • the overvoltage protection circuit 50 includes an impedance circuit 20, a voltage detector 33, and a bypass circuit 35.
  • Impedance circuit 20 is a circuit configured such that an impedance that is a ratio of a voltage and a current in the circuit is Z.
  • the impedance circuit 20 is connected between the commercial power supply 90 and the device 30 on the power supply line 902.
  • FIG. 2 is a circuit diagram of a general voltage detector 33.
  • the voltage detector 33 includes a transformer circuit 331 and a converter circuit 332.
  • the transformer circuit 331 is located on the input side and includes a primary winding 331a and a secondary winding 331b.
  • the converter circuit 332 is a circuit in which a rectifying unit 332a composed of a rectifying diode and a smoothing capacitor 332b are connected in parallel.
  • the voltage detector 33 when an AC voltage is applied to the transformer circuit 331, the AC voltage is transformed by the transformer circuit 331. Then, the voltage across the secondary winding 331 b is input to the converter circuit 332.
  • the AC voltage after transformation input to the converter circuit 332 is converted into a DC voltage by the rectifying unit 332a and smoothed by the smoothing capacitor 332b.
  • This smoothed DC voltage is input to the control unit 40. That is, a DC voltage corresponding to the voltage applied to the primary winding 331a is input to the control unit 40.
  • the bypass circuit 35 is connected to the impedance circuit 20 in parallel and bypasses the impedance circuit 20.
  • the bypass circuit 35 has a switch 11.
  • the switch 11 opens and closes the bypass circuit 35.
  • opening and closing the bypass circuit 35 means making the bypass circuit 35 conductive or non-conductive to make it non-conductive.
  • the switch 11 normally closes the bypass circuit 35, that is, keeps it conductive. This is because if the bypass circuit 35 is left open (non-conducting state) during normal operation, the impedance circuit 20 is always connected and power is always consumed, and the voltage applied to the device 30 is applied to the impedance circuit 20. This is because the voltage drops by the voltage drop of the impedance Z.
  • a triac As the switch 11, a triac, a MOSFET connected so as to conduct in both directions, or the like is employed. In the present embodiment, a phototriac coupler is employed.
  • the switch 11 is provided with a light emitting diode 11a on the input side (between A1 and A2) and a phototriac 11b on the output side (between B1 and B2).
  • the equivalent circuit of the phototriac 11b has a configuration in which two photothyristors 111 and 112 are connected in parallel in opposite directions.
  • the anode A1 of the light emitting diode 11a is connected to the power source Vc via the resistor R1.
  • the cathode A2 of the light emitting diode 11a is connected to the control unit 40 through a signal line.
  • the first anode B1 of the phototriac 11b is connected between the impedance circuit 20 in the power supply line 902 and the device 30.
  • the second anode B2 of the phototriac 11b is connected to the power supply line 902 between the impedance circuit 20 and the commercial power supply 90.
  • the light emitting diode 11a emits light when a current flows.
  • the phototriac 11b receives light from the light emitting diode 11a in a state where the potential of the first anode B1 is higher than the potential of the second anode B2, the photothyristor 111 is turned on.
  • the photothyristor 112 is turned on.
  • the phototriac 11b is a bidirectional element that operates with respect to a bidirectional applied voltage, and also operates at a high speed, so that it is used as a bidirectional high-speed switch.
  • the bidirectional high-speed switch is not limited to the photo triac, but a normal triac or a MOSFET connected so as to conduct in both directions may be employed.
  • a drive circuit corresponding to the form of the switch is appropriately used.
  • control unit 40 performs operation control of the switch 11, that is, energization control to the light emitting diode 11a.
  • FIG. 3 is a graph showing changes in the voltage V when the impedance of the device 30 is only a resistance component and the impedance Z is only a resistance.
  • the control unit 40 determines that the voltage output from the voltage detector 33 has exceeded the threshold, the control unit 40 stops energizing the light emitting diode 11a of the switch 11. Then, the photo triac 11b is turned off. In order to protect the device 30, the switch 11 is required to operate at high speed.
  • FIG. 4 is a graph showing a change in the voltage V when the impedance Z includes an inductance component.
  • the increase in the voltage V after the switch 11 is turned off is Compared to the case where the impedance Z is only a resistance, it rises more slowly.
  • the impedance Z includes an inductance component in an area where the power supply voltage is likely to fluctuate and the overvoltage continues for a long time.
  • control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 energizes the light emitting diode 11a of the switch 11, The photo triac 11b is turned on. As a result, the normal operation is restored.
  • FIG. 5 is a circuit diagram of a device including an overvoltage protection circuit 50 according to the second embodiment of the present invention.
  • the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902.
  • the overvoltage protection circuit 50 is connected between the commercial power supply 90 and the device 30.
  • the overvoltage protection circuit 50 includes an impedance circuit 20, a voltage detector 33, a bypass circuit 35, and the second switch 12.
  • Second switch 12 The second switch 12 opens and closes the power line 901.
  • opening and closing the power supply line 901 means that the power supply line 901 is turned on or off to make it non-conductive.
  • the second switch 12 normally closes the power supply line 901, that is, keeps it conductive. On the other hand, at the time of overvoltage, the switch 11 is turned off to form a closed circuit of the commercial power supply 90-the device 30-the impedance circuit 20-the commercial power supply 90, and after the protection operation of the device 30 is performed, the second switch 12 is turned off. Then, the power line 901 is shut off.
  • the purpose of cutting off the power supply line 901 is to stop the power consumption in the impedance circuit 20, the power rating of the impedance circuit 20 can be reduced, and the cost can be reduced.
  • the second switch 12 includes a relay contact 12a for opening and closing the power supply line 901, a relay coil 12b for operating the relay contact 12a, and a transistor 12c for energizing and de-energizing the relay coil 12b. Is included. One end of the relay coil 12b is connected to the positive electrode of the power source Vb, and the other end is connected to the collector side of the transistor 12c.
  • the control unit 40 switches the presence / absence of the base current of the transistor 12c, turns on / off the collector and the emitter, and energizes and de-energizes the relay coil 12b.
  • the control unit 40 determines that the voltage output from the voltage detector 33 has exceeded the threshold, the control unit 40 stops energizing the light emitting diode 11a of the switch 11. Then, the photo triac 11b is turned off.
  • the voltage V applied to the device 30 increases as the voltage Vac of the commercial power supply 90 increases.
  • the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches the second threshold value. As a result, the device 30 is protected and power consumption in the impedance circuit 20 is stopped.
  • the impedance Z includes an inductance component
  • the increase in the voltage V after the switch 11 is turned off is that the impedance Z is only a resistance. Compared to the case, it rises more slowly.
  • the damage is small compared to the case where the impedance Z is only a resistance. That is, the device 30 can be protected from a short-time overvoltage even when the power rating of the impedance Z is small.
  • control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 energizes the light emitting diode 11a of the switch 11. Then, the photo triac 11b is turned on. Further, the second switch 12 is turned on and the power supply line 901 is connected to return to the normal operation.
  • the second switch 12 cuts off the power supply line 901 to stop power consumption in the impedance circuit 20. As a result, overheating of the impedance circuit 20 can be suppressed and the power rating can be reduced.
  • FIG. 7 is a circuit diagram of a power converter 300 including an overvoltage protection circuit 100 according to the third embodiment of the present invention.
  • the power conversion device 300 includes a DC power supply unit 80, an inverter 95, and an overvoltage protection circuit 100.
  • the inverter 95 is supplied with power from the DC power supply unit 80 via a pair of power supply lines 801 and 802.
  • the overvoltage protection circuit 100 is connected between the DC power supply unit 80 and the inverter 95.
  • the DC power supply unit 80 includes a rectifying unit 81 and a smoothing capacitor 82 connected in parallel with the rectifying unit 81.
  • the rectifying unit 81 is configured in a bridge shape by four diodes D1a, D1b, D2a, and D2b. Specifically, the diodes D1a and D1b and D2a and D2b are respectively connected in series. The cathode terminals of the diodes D1a and D2a are both connected to the plus side terminal of the smoothing capacitor 82 and function as the positive side output terminal of the rectifying unit 81. The anode terminals of the diodes D1b and D2b are both connected to the minus terminal of the smoothing capacitor 82 and function as the negative output terminal of the rectifier 81.
  • connection point of the diode D1a and the diode D1b is connected to one pole of the commercial power supply 90.
  • a connection point between the diode D2a and the diode D2b is connected to the other pole of the commercial power supply 90.
  • the rectifying unit 81 rectifies the AC voltage output from the commercial power supply 90 to generate a DC voltage, and supplies this to the smoothing capacitor 82.
  • the smoothing capacitor 82 smoothes the voltage rectified by the rectifying unit 81.
  • the smoothed voltage Vdc is applied to the inverter 95 connected to the output side of the smoothing capacitor 82.
  • the DC power supply unit 80 can be rephrased as a converter circuit that converts an AC voltage into a DC voltage.
  • the inverter 95 includes a plurality of IGBTs (insulated gate bipolar transistors, hereinafter simply referred to as transistors) and a plurality of free-wheeling diodes.
  • the inverter 95 is applied with the voltage Vdc from the smoothing capacitor 82, and each transistor is turned on and off at the timing instructed by the gate drive circuit 96, thereby generating a drive voltage for driving the motor 500.
  • the motor 500 is, for example, a compressor motor or a fan motor of a heat pump type air conditioner.
  • inverter 95 of this embodiment is a voltage source inverter, it is not limited to it, A current source inverter may be sufficient.
  • Gate drive circuit 96 The gate drive circuit 96 changes the on / off state of each transistor of the inverter 95 based on a command from the control unit 40.
  • the overvoltage protection circuit 100 includes an impedance circuit 70, a voltage detector 83, a bypass circuit 85, and a second switch 62.
  • the third embodiment is different from the first and second embodiments already described in that the overvoltage protection circuit 100 is provided in the direct current section. Therefore, in view of the fact that each component is also replaced from the AC specification to the DC specification, the description will be given again by changing the code even if the names are the same.
  • the impedance circuit 70 is a circuit configured such that an impedance that is a ratio of a voltage and a current in the circuit is Z. In general, a resistance element is employed.
  • the impedance circuit 70 is connected between the DC power supply unit 80 and the inverter 95 on the power supply line 802.
  • the voltage detector 83 is connected to the output side of the smoothing capacitor 82, and detects the voltage across the smoothing capacitor 82, that is, the value of the smoothed voltage Vdc.
  • the voltage detector 83 is configured such that two resistors connected in series with each other are connected in parallel to the smoothing capacitor 82 and the voltage Vdc is divided. The voltage value at the connection point between the two resistors is input to the control unit 40.
  • the bypass circuit 85 is a circuit that is connected in parallel to the impedance circuit 70 and bypasses the impedance circuit 70.
  • the bypass circuit 85 has a switch 61.
  • the switch 61 opens and closes the bypass circuit 85.
  • opening and closing the bypass circuit 85 means making the bypass circuit 85 conductive or blocked to make it non-conductive.
  • the switch 61 normally closes the bypass circuit 85, that is, keeps it conductive. This is because if the bypass circuit 85 is left open (non-conducting state) during normal operation, power is always consumed by the impedance circuit 70 and the voltage applied to the inverter 95 is lowered by the voltage drop of the impedance Z of the impedance circuit 70. Because it becomes.
  • the switch 61 is required to operate at high speed.
  • a transistor is employed, but the form of the switch 61 is not limited to this embodiment.
  • the switch 61 is composed of a photocoupler 61a, a drive circuit 61b, and a transistor 61c.
  • the photocoupler 61a includes a light emitting diode 611 and a phototransistor 612.
  • the light emitting diode 611 of the photocoupler 61a is connected to the input side (between C1 and C2) of the switch 61.
  • the anode C1 of the light emitting diode 611 is connected to the power source Vc via the resistor R1.
  • the cathode C2 of the light emitting diode 611 is connected to the control unit 40 via a signal line.
  • the phototransistor 612 is connected between the drive circuit 61b and GND.
  • a transistor 61c is provided on the output side (between D1 and D2) of the switch 61.
  • the collector D1 of the transistor 61c is connected between the impedance circuit 70 and the inverter 95.
  • the emitter D2 of the transistor 61c is connected between the impedance circuit 70 and the DC power supply unit 80.
  • the control signal of the control unit 40 is input to the drive circuit 61b via the photocoupler 61a.
  • a driving power supply (not shown) is connected to the driving circuit 61b.
  • the control unit 40 turns on the signal line of the light emitting diode 611, the light emitting diode 611 emits light and the phototransistor 612 becomes conductive. While the phototransistor 612 is conducting, a driving signal is output from the driving circuit 61b to the base of the transistor 61c, and the collector D1-emitter D2 of the transistor 61c is conducted.
  • control unit 40 turns off the signal line of the light emitting diode 611, the light emitting diode 611 does not emit light, and the phototransistor 612 does not conduct. While the phototransistor 612 is not conducting, the collector D1 and the emitter D2 of the transistor 61c are not conducted.
  • Second switch 62 The second switch 62 opens and closes the power line 801.
  • opening and closing the power supply line 801 is to turn the power supply line 801 on or off to make it non-conductive.
  • the second switch 62 normally closes the power supply line 801, that is, keeps it conductive. On the other hand, when overvoltage occurs, the switch 61 is turned off to form a closed circuit of the DC power supply unit 80-inverter 95-impedance circuit 70-DC power supply unit 80. After the protective operation of the inverter 95 is performed, the second switch 62 Is turned off and the power line 801 is shut off.
  • the purpose of cutting off the power supply line 801 is to stop the power consumption in the impedance circuit 70, the power rating of the impedance circuit 70 can be reduced, and the cost can be reduced.
  • the second switch 62 includes a relay contact 62a for opening and closing the power supply line 801, a relay coil 62b for operating the relay contact 62a, and a transistor 62c for energizing and de-energizing the relay coil 62b. Is included. One end of the relay coil 62b is connected to the positive electrode of the power supply Vb, and the other end is connected to the collector side of the transistor 62c. The controller 40 switches between the presence and absence of the base current of the transistor 62c, turns on and off the collector and the emitter, and performs energization and de-energization of the relay coil 62b.
  • the control unit 40 determines that the voltage output from the voltage detector 83 exceeds the threshold value, the control unit 40 stops energizing the light emitting diode 611 of the switch 61. Then, the phototransistor 612 is turned off.
  • the second switch 62 cuts off the power supply line 801 and stops the power consumption in the impedance circuit 70.
  • control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 83 has fallen below the threshold for recovery, the control unit 40 energizes the light emitting diode 611 of the switch 61, The transistor 61c is turned on. Further, by turning on the second switch 62 and connecting the power supply line 801, the normal operation is restored.
  • the switch 61 is normally turned on and the bypass circuit 85 is closed, so that no power is consumed in the impedance circuit 70, and the voltage applied to the inverter 95 is the voltage at the impedance circuit 70. It is also possible to avoid lowering by the amount of descent.
  • the second switch 62 cuts off the power supply line 801 to stop the power consumption in the impedance circuit 70. As a result, the power rating of the impedance circuit 70 can be reduced.
  • the switch 61 arranged on the downstream side of the DC power supply unit 80 may be a one-way switch, the cost of the switch can be reduced.
  • FIG. 8 is a circuit diagram of a power conversion device 300 including the overvoltage protection circuit 100 according to the fourth embodiment of the present invention.
  • the inverter 95 is supplied with power from a DC power supply unit 80 via a pair of power supply lines 801 and 802.
  • a part of the overvoltage protection circuit 100 is connected between the commercial power supply 90 and the DC power supply unit 80, and the other part is connected between the DC power supply unit 80 and the inverter 95.
  • the overvoltage protection circuit 100 includes an impedance circuit 70, a voltage detector 33, a bypass circuit 85, and the second switch 12.
  • a voltage detector and a second switch which are components of the overvoltage protection circuit 100, are provided between the commercial power supply 90 and the DC power supply unit 80. It is that. That is, the arrangement of the voltage detector and the second switch is the same as the arrangement of the voltage detector 33 and the second switch 12 in the second embodiment. Therefore, in view of the fact that the voltage detector and the second switch are replaced from the DC specification to the AC specification, the voltage detector 33 and the second switch 12 of the second embodiment are employed.
  • each component is the same as that of the voltage detector 33 and the second switch 12 of the second embodiment, the impedance circuit 70 of the third embodiment, and the bypass circuit 85. Only the operation is explained.
  • the control unit 40 determines that the voltage output from the voltage detector 33 exceeds the threshold, and the switch The current supply to the light emitting diode 611 of 61 is stopped, and the transistor 61c is turned off.
  • the second switch 12 cuts off the power supply line 901 and stops the power consumption in the impedance circuit 70.
  • the switch 61 is normally turned on and the bypass circuit 85 is closed, so that no power is consumed in the impedance circuit 70, and the voltage applied to the inverter 95 is the voltage at the impedance circuit 70. It is also possible to avoid lowering by the amount of descent.
  • the second switch 12 cuts off the power supply line 901 to stop the power consumption in the impedance circuit 70. As a result, overheating of the impedance circuit 70 can be suppressed and the power rating can be reduced.
  • the switch 61 arranged on the downstream side of the DC power supply unit 80 may be a one-way switch, the cost of the switch can be reduced.
  • the overvoltage protection circuit 50 according to the first embodiment shown in FIG. 1 is an overvoltage protection circuit for an AC voltage, but when the power supply is a DC power supply, or a DC power supply unit that rectifies the AC power supply in the device. In the case of having it, each component may be replaced from the AC specification to the DC specification and provided on the downstream side of the DC power supply unit.
  • the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches a predetermined second threshold, but it may be cut off when the overvoltage state has passed a predetermined duration. Good.
  • the control unit 40 determines that the voltage output from the voltage detector 33 has exceeded the threshold, the control unit 40 stops energizing the light emitting diode 11a of the switch 11. Then, the photo triac 11b is turned off.
  • the voltage V applied to the device 30 increases as the voltage Vac of the commercial power supply 90 increases, but the overvoltage state continues for a predetermined duration after the voltage Vac exceeds the threshold value.
  • the second switch 12 cuts off the power supply line 901. As a result, the device 30 is protected and power consumption in the impedance circuit 20 is stopped.
  • the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches a predetermined second threshold.
  • a device voltage detector 37 for detecting the voltage V applied to the device is further provided. The voltage V may be cut off when it reaches a predetermined third threshold (a circuit diagram at this time is shown in FIG. 11).
  • the control unit 40 determines that the voltage output from the voltage detector 33 has exceeded the threshold, the control unit 40 stops energizing the light emitting diode 11a of the switch 11. Then, the photo triac 11b is turned off.
  • the voltage V applied to the device 30 increases as the voltage Vac of the commercial power supply 90 increases, but when the voltage V reaches the third threshold value, the second switch 12 cuts off the power line 901. As a result, the device 30 is protected and power consumption in the impedance circuit 20 is stopped.
  • the fourth embodiment is different from the third embodiment in that the voltage detector and the second switch are provided between the commercial power supply 90 and the DC power supply unit 80, but only the voltage detector is commercialized. You may make it provide between the power supply 90 and the DC power supply part 80.
  • FIG. 12 is a circuit diagram of a device including an overvoltage protection circuit 150 according to the fifth embodiment of the present invention.
  • the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902.
  • the overvoltage protection circuit 150 is connected between the commercial power supply 90 and the device 30.
  • the overvoltage protection circuit 150 includes a variable impedance circuit 120 and a voltage detector 33.
  • variable impedance circuit 120 is a circuit configured such that an impedance that is a ratio of a voltage and a current in the circuit is Z.
  • the impedance Z is variable.
  • variable impedance circuit 120 is connected between the commercial power supply 90 and the device 30 on the power supply line 902.
  • the voltage detector 33 is configured by an AC voltage detection circuit. There are various AC voltage detection circuits, and they are appropriately adopted depending on use conditions. Specifically, for example, the voltage detector (see FIG. 2) employed in the first embodiment and the second embodiment is the same as the voltage detector, and the description thereof is omitted here.
  • FIG. 13 is a graph showing changes in the voltage V when the impedance of the device 30 is only the resistance component, the impedance Z is only the variable resistance, and the impedance Z continuously increases. is there. 12 and 13, since the impedance Z is 0 or a value close to 0 at normal time, the voltage V ⁇ Vac is applied to the device 30.
  • the control unit 40 determines that the voltage output from the voltage detector 33 exceeds V 0.
  • the control unit 40 continuously increases the impedance Z in accordance with the increase in the detection value of the voltage detector 33.
  • the voltage V Vac ⁇ Vz obtained by subtracting the voltage drop Vz at both ends of the variable impedance circuit 120 is applied to the device 30, and the device 30 is protected from overvoltage.
  • control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 sets the impedance Z of the variable impedance circuit 120 to 0 or Return to a value close to zero. As a result, the normal operation is restored.
  • the change in the impedance Z is not necessarily a continuous increase as shown in FIG. 13, and may be an intermittent increase.
  • FIG. 14 is a graph showing a change in the voltage V when the impedance of the device 30 is only the resistance component, the impedance Z is only the variable resistance, and the impedance Z increases stepwise.
  • the impedance Z is set to a large value at the time of overvoltage, the voltage applied to the device 30 is reduced by the voltage drop Vz in the variable impedance circuit 120, and the device 30 can be protected from the overvoltage.
  • variable impedance circuit 120 can continuously change the impedance Z according to the change in the detection value by the voltage detector 33.
  • variable impedance circuit 120 can change the impedance Z in a stepwise manner in accordance with the change in the detection value by the voltage detector 33.
  • FIG. 15 is a circuit diagram of a device including an overvoltage protection circuit 150 according to the sixth embodiment of the present invention.
  • the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902.
  • the overvoltage protection circuit 150 is connected between the commercial power supply 90 and the device 30.
  • the overvoltage protection circuit 150 includes a variable impedance circuit 120 and a voltage detector 33.
  • variable impedance circuit 120 is configured by a plurality of impedance elements, but other configurations are the fifth embodiment. Is the same. Therefore, only the variable impedance circuit 120 will be described here.
  • variable impedance circuit 120 includes a low impedance element 121, a high impedance element 122, and a changeover switch 123.
  • the variable impedance circuit 120 can selectively use the low impedance element 121 and the high impedance element 122 by the changeover switch 123.
  • the low impedance element 121 has an impedance Z 1 .
  • the high impedance element 122 has an impedance Z 2 that is greater than the impedance Z 1 .
  • the variable impedance circuit 120 can switch the impedance element to be used from the low impedance element 121 to the high impedance element 122 when the detection value of the voltage detector 33 exceeds a predetermined threshold when the low impedance element 121 is used.
  • FIG. 16 is a graph showing changes in the voltage V when the impedance of the device 30 is only the resistance component and the impedance Z is only the resistance. 15 and 16, the variable impedance circuit 120 is normally connected to the low impedance element 121 at the contact point of the changeover switch 123 in the variable impedance circuit 120. Since the impedance Z 1 of the low impedance element 121 is 0 or a value close to 0, the voltage V ⁇ Vac is applied to the device 30.
  • the controller 40 uses the low impedance element 121 of the variable impedance circuit 120 to maintain the impedance Z 1 even when the voltage Vac of the commercial power supply 90 exceeds the normal value V 0 .
  • control unit 40 operates the changeover switch 123 to connect the contact point to the high impedance element 122.
  • the voltage V applied to the device 30 decreases from V 1 to V 0 , and the device 30 is protected from overvoltage.
  • control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 sets the impedance element of the variable impedance circuit 120 to a high impedance Switching from element 122 to low impedance element 121 returns impedance Z 2 to impedance Z 1 . As a result, the normal operation is restored.
  • overvoltage protection circuit 150 In the overvoltage protection circuit 150, during overvoltage, the voltage applied to the device 30 is reduced by the voltage drop in the variable impedance circuit 120, and the device 30 can be protected from overvoltage.
  • FIG. 17 is a circuit diagram of a device including an overvoltage protection circuit 150 according to the seventh embodiment of the present invention.
  • the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902.
  • the overvoltage protection circuit 150 is connected between the commercial power supply 90 and the device 30.
  • the overvoltage protection circuit 150 includes a variable impedance circuit 120, a voltage detector 33, and a second switch 12.
  • Second switch 12 The second switch 12 opens and closes the power line 901.
  • opening and closing the power supply line 901 means that the power supply line 901 is turned on or off to make it non-conductive.
  • the second switch 12 normally closes the power supply line 901, that is, keeps it conductive. On the other hand, at the time of overvoltage, the second switch 12 is turned off and the power supply line 901 is shut off after the protection operation of the device 30 is performed by changing the impedance Z of the variable impedance circuit 120.
  • variable impedance circuit 120 is used when the overvoltage of the power supply exceeds the assumed voltage when the variable impedance circuit is designed, or when the duration of the overvoltage state exceeds the assumed time. Therefore, the power rating of the variable impedance circuit 120 can be reduced, and the cost can be reduced.
  • the second switch 12 employs a relay circuit.
  • the second switch 12 includes a relay contact 12a for opening and closing the power supply line 901, a relay coil 12b for operating the relay contact 12a, and a transistor 12c for energizing and de-energizing the relay coil 12b. Is included. One end of the relay coil 12b is connected to the positive electrode of the power source Vb, and the other end is connected to the collector side of the transistor 12c.
  • the control unit 40 switches the presence / absence of the base current of the transistor 12c, turns on / off the collector and the emitter, and energizes and de-energizes the relay coil 12b.
  • FIG. 18 is a graph showing changes in the voltage V when the impedance of the device 30 is only the resistance component and the impedance Z is only the resistance.
  • the second switch 12 keeps the power supply line 901 conductive during normal times. Since the impedance Z of the variable impedance circuit 120 is 0 or a value close to 0, the voltage V ⁇ Vac is applied to the device 30.
  • the voltage Vac of the commercial power supply 90 increases and the control unit 40 determines that the voltage output from the voltage detector 33 exceeds V 0.
  • the control unit 40 continuously increases the impedance Z in accordance with the increase in the detection value of the voltage detector 33.
  • the voltage V Vac ⁇ Vz obtained by subtracting the voltage drop Vz at both ends of the variable impedance circuit 120 is applied to the device 30, and the device 30 is protected from overvoltage.
  • the voltage V applied to the device 30 increases as the voltage Vac of the commercial power supply 90 increases.
  • the second switch 12 cuts off the power supply line 901 when the voltage Vac reaches the first threshold value V 1 .
  • the device 30 is protected and power consumption in the variable impedance circuit 120 is stopped.
  • control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 sets the impedance Z of the variable impedance circuit 120 to 0 or Return to a value close to zero. Further, the second switch 12 is turned on and the power supply line 901 is connected to return to the normal operation.
  • overvoltage protection circuit 150 In the overvoltage protection circuit 150, during overvoltage, the voltage applied to the device 30 is reduced by the voltage drop in the variable impedance circuit 120, and the device 30 can be protected from overvoltage.
  • the second switch 12 cuts off the power supply line 901 to stop power consumption in the variable impedance circuit 120. As a result, overheating of the variable impedance circuit 120 can be suppressed and the power rating can be reduced.
  • FIG. 19 is a circuit diagram of a device including an overvoltage protection circuit 150 according to the eighth embodiment of the present invention.
  • the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902.
  • the overvoltage protection circuit 150 is connected between the commercial power supply 90 and the device 30.
  • the overvoltage protection circuit 150 includes a variable impedance circuit 120, a voltage detector 33, and a second switch 12.
  • variable impedance circuit 120 is configured by a plurality of impedance elements, but the other configurations are the seventh embodiment. Is the same. Therefore, only the variable impedance circuit 120 will be described here.
  • variable impedance circuit 120 includes a low impedance element 121, a high impedance element 122, and a changeover switch 123.
  • the variable impedance circuit 120 can selectively use the low impedance element 121 and the high impedance element 122 by the changeover switch 123.
  • the low impedance element 121 has an impedance Z 1 .
  • the high impedance element 122 has an impedance Z 2 that is greater than the impedance Z 1 .
  • the variable impedance circuit 120 can switch the impedance element to be used from the low impedance element 121 to the high impedance element 122 when the detection value of the voltage detector 33 exceeds a predetermined threshold when the low impedance element 121 is used.
  • FIG. 20 is a graph showing a change in voltage V when the impedance of the device 30 is only a resistance component and the impedance Z is only a resistance.
  • the variable impedance circuit 120 normally has a contact point of the changeover switch 123 connected to the low impedance element 121. Since the impedance Z 1 of the low impedance element 121 is 0 or a value close to 0, the voltage V ⁇ Vac is applied to the device 30.
  • the voltage Vac of the commercial power supply 90 at normal time is V 0 or less.
  • the controller 40 uses the low impedance element 121 of the variable impedance circuit 120 to maintain the impedance Z 1 even when the voltage Vac of the commercial power supply 90 exceeds the normal value V 0 .
  • control unit 40 operates the changeover switch 123 to connect the contact point to the high impedance element 122.
  • the voltage V applied to the device 30 decreases from V 1 to V 0 , and the device 30 is protected from overvoltage.
  • V applied to the device 30 increases as the voltage Vac of the commercial power supply 90 increases.
  • control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 sets the impedance element of the variable impedance circuit 120 to a high impedance Switching from element 122 to low impedance element 121 returns impedance Z 2 to impedance Z 1 . Further, the second switch 12 is turned on and the power supply line 901 is connected to return to the normal operation.
  • the overvoltage protection circuit 150 switches the impedance element of the variable impedance circuit 120 from the low impedance element 121 to the high impedance element 122 at the time of overvoltage, so that the voltage applied to the device 30 is reduced by the voltage drop at the impedance Z 2 .
  • the device 30 can be protected from overvoltage.
  • the second switch 12 cuts off the power supply line 901 to stop power consumption in the variable impedance circuit 120. As a result, overheating of the variable impedance circuit 120 can be suppressed and the power rating can be reduced.
  • FIG. 21 is a circuit diagram of a power converter 300 including an overvoltage protection circuit 200 according to the ninth embodiment of the present invention.
  • the power conversion device 300 includes a DC power supply unit 80, an inverter 95, and an overvoltage protection circuit 200.
  • the inverter 95 is supplied with power from the DC power supply unit 80 via a pair of power supply lines 801 and 802.
  • the overvoltage protection circuit 200 is connected between the DC power supply unit 80 and the inverter 95.
  • the DC power supply unit 80 includes a rectifying unit 81 and a smoothing capacitor 82 connected in parallel with the rectifying unit 81.
  • the rectifying unit 81 is configured in a bridge shape by four diodes D1a, D1b, D2a, and D2b. Specifically, the diodes D1a and D1b and D2a and D2b are respectively connected in series. The cathode terminals of the diodes D1a and D2a are both connected to the plus side terminal of the smoothing capacitor 82 and function as the positive side output terminal of the rectifying unit 81. The anode terminals of the diodes D1b and D2b are both connected to the minus terminal of the smoothing capacitor 82 and function as the negative output terminal of the rectifier 81.
  • connection point of the diode D1a and the diode D1b is connected to one pole of the commercial power supply 90.
  • a connection point between the diode D2a and the diode D2b is connected to the other pole of the commercial power supply 90.
  • the rectifying unit 81 rectifies the AC voltage output from the commercial power supply 90 to generate a DC voltage, and supplies this to the smoothing capacitor 82.
  • the smoothing capacitor 82 smoothes the voltage rectified by the rectifying unit 81.
  • the smoothed voltage Vdc is applied to the inverter 95 connected to the output side of the smoothing capacitor 82.
  • an electrolytic capacitor is employ
  • FIG. 1 An electrolytic capacitor, a film capacitor, etc. are mentioned as a kind of capacitor
  • the DC power supply unit 80 can be rephrased as a converter circuit that converts an AC voltage into a DC voltage.
  • the inverter 95 includes a plurality of IGBTs (insulated gate bipolar transistors, hereinafter simply referred to as transistors) and a plurality of free-wheeling diodes.
  • the inverter 95 is applied with the voltage Vdc from the smoothing capacitor 82, and each transistor is turned on and off at the timing instructed by the gate drive circuit 96, thereby generating a drive voltage for driving the motor 500.
  • the motor 500 is, for example, a compressor motor or a fan motor of a heat pump type air conditioner.
  • inverter 95 of this embodiment is a voltage source inverter, it is not limited to it, A current source inverter may be sufficient.
  • Gate drive circuit 96 The gate drive circuit 96 changes the on / off state of each transistor of the inverter 95 based on a command from the control unit 40.
  • the overvoltage protection circuit 200 includes a variable impedance circuit 170, a voltage detector 83, and a second switch 62.
  • the ninth embodiment is different from the seventh embodiment and the eighth embodiment already described in that the overvoltage protection circuit 200 is provided in the direct current section. Therefore, in view of the fact that each component is also replaced from the AC specification to the DC specification, the description will be given again by changing the code even if the names are the same.
  • variable impedance circuit 170 is a circuit configured such that an impedance that is a ratio of a voltage and a current in the circuit is Z. In general, a resistance element is employed.
  • variable impedance circuit 170 is connected between the DC power supply unit 80 and the inverter 95 on the power supply line 802.
  • the variable impedance circuit 170 includes a low impedance element 171, a high impedance element 172, and a changeover switch 173.
  • the variable impedance circuit 170 can selectively use the low impedance element 171 and the high impedance element 172 by the changeover switch 173.
  • Low impedance element 171 has an impedance Z 1.
  • the high impedance element 172 has an impedance Z 2 that is greater than the impedance Z 1 .
  • the variable impedance circuit 170 can switch the impedance element to be used from the low impedance element 171 to the high impedance element 172 when the detection value of the voltage detector 83 exceeds a predetermined threshold when the low impedance element 171 is used.
  • the voltage detector 83 is connected to the output side of the smoothing capacitor 82, and detects the voltage across the smoothing capacitor 82, that is, the value of the smoothed voltage Vdc.
  • the voltage detector 83 is configured such that two resistors connected in series with each other are connected in parallel to the smoothing capacitor 82 and the voltage Vdc is divided. The voltage value at the connection point between the two resistors is input to the control unit 40.
  • Second switch 62 opens and closes the power line 801.
  • opening and closing the power supply line 801 is to turn the power supply line 801 on or off to make it non-conductive.
  • the second switch 62 normally closes the power supply line 801, that is, keeps it conductive. On the other hand, at the time of overvoltage, the second switch 62 is turned off and the power supply line 801 is shut off after the protection operation of the inverter 95 is performed by the impedance Z of the variable impedance circuit 170 changing.
  • the purpose of cutting off the power supply line 801 is to stop the power consumption in the variable impedance circuit 170, the power rating of the variable impedance circuit 170 can be reduced, and the cost can be reduced.
  • the second switch 62 employs a relay circuit.
  • the second switch 62 includes a relay contact 62a for opening and closing the power supply line 801, a relay coil 62b for operating the relay contact 62a, and a transistor 62c for energizing and de-energizing the relay coil 62b. Is included. One end of the relay coil 62b is connected to the positive electrode of the power supply Vb, and the other end is connected to the collector side of the transistor 62c. The controller 40 switches between the presence and absence of the base current of the transistor 62c, turns on and off the collector and the emitter, and performs energization and de-energization of the relay coil 62b.
  • the second switch 62 keeps the power supply line 801 conductive during normal operation.
  • the variable impedance circuit 170 has a contact point of the changeover switch 173 connected to the low impedance element 171. Since the impedance Z 1 of the low impedance element 171 is 0 or a value close to 0, the voltage V ⁇ Vdc is applied to the inverter 95.
  • the control unit 40 operates the changeover switch 173 to connect the contact point to the high impedance element 172.
  • the impedance Z 2 of the high impedance element 172 is larger than the impedance Z 1 of the low impedance element 171
  • the voltage V applied to the inverter 95 decreases, and the inverter 95 is protected from overvoltage.
  • the second switch 62 cuts off the power supply line 801 when the voltage Vdc of the DC power supply unit 80 reaches the second threshold (or may be the first threshold). As a result, the inverter 95 is protected from overvoltage and the power consumption in the variable impedance circuit 170 is stopped.
  • control unit 40 determines that the voltage Vdc of the DC power supply unit 80 has dropped and the voltage output from the voltage detector 83 has fallen below the threshold for recovery, the control unit 40 increases the impedance element of the variable impedance circuit 170 to a high level. Switching from the impedance element 172 to the low impedance element 171 returns the impedance Z 2 to the impedance Z 1 . Further, by turning on the second switch 62 and connecting the power supply line 801, the normal operation is restored.
  • the overvoltage protection circuit 200 during an overvoltage, by switching the impedance components of the variable impedance circuit 170 to a high impedance element 172, the voltage applied to the voltage drop by the inverter 95 in the impedance Z 2 is reduced, the overvoltage inverters 95 Can be protected from.
  • the second switch 62 cuts off the power supply line 801 to stop the power consumption in the variable impedance circuit 170. As a result, the power rating of the variable impedance circuit 170 can be reduced.
  • FIG. 22 is a circuit diagram of a power conversion device 300 including the overvoltage protection circuit 200 according to the tenth embodiment of the present invention.
  • the inverter 95 is supplied with power from a DC power supply unit 80 via a pair of power supply lines 801 and 802.
  • a part of the overvoltage protection circuit 200 is connected between the commercial power supply 90 and the DC power supply unit 80, and the other part is connected between the DC power supply unit 80 and the inverter 95.
  • the overvoltage protection circuit 200 includes a variable impedance circuit 170, a voltage detector 33, and a second switch 12.
  • a voltage detector which is a component of the overvoltage protection circuit 200
  • a second switch are provided between the commercial power supply 90 and the DC power supply unit 80. It is that. That is, the arrangement of the voltage detector and the second switch is the same as the arrangement of the voltage detector 33 and the second switch 12 in the eighth embodiment. Therefore, in view of the fact that the voltage detector and the second switch are replaced from the DC specification to the AC specification, the voltage detector 33 and the second switch 12 of the eighth embodiment are employed.
  • each component is the same as that of the voltage detector 33 and the second switch 12 of the eighth embodiment and the variable impedance circuit 170 of the ninth embodiment. .
  • the second switch 12 keeps the power supply line 901 conductive during normal operation.
  • the variable impedance circuit 170 has a contact point of the changeover switch 173 connected to the low impedance element 171. Since the impedance Z 1 of the low impedance element 171 is 0 or a value close to 0, the voltage V ⁇ Vdc is applied to the inverter 95.
  • the control unit 40 When the voltage Vdc of the DC power supply unit 80 increases due to the fluctuation of the voltage Vac of the commercial power supply 90 and the detected value of the voltage detector 33 exceeds the first threshold value, the control unit 40 operates the changeover switch 173 to change the contact point. Connect to high impedance element 172.
  • the impedance Z 2 of the high impedance element 172 is larger than the impedance Z 1 of the low impedance element 171
  • the voltage V applied to the inverter 95 decreases, and the inverter 95 is protected from overvoltage.
  • control unit 40 determines that the voltage Vac of the commercial power supply 90 is stable, the voltage Vdc of the DC power supply unit 80 is decreased, and the voltage output from the voltage detector 33 is lower than the threshold for recovery, the control unit 40 Switches the impedance element of the variable impedance circuit 170 from the high impedance element 172 to the low impedance element 171 to return the impedance Z 2 to the impedance Z 1 . Further, the second switch 12 is turned on and the power supply line 901 is connected to return to the normal operation.
  • the overvoltage protection circuit 200 during an overvoltage, by switching the impedance components of the variable impedance circuit 170 to a high impedance element 172, the voltage applied to the voltage drop by the inverter 95 in the impedance Z 2 is reduced, the overvoltage inverters 95 Can be protected from.
  • the second switch 12 cuts off the power supply line 901 to stop power consumption in the variable impedance circuit 170. As a result, overheating of the variable impedance circuit 170 can be suppressed and the power rating can be reduced.
  • the overvoltage protection circuit 150 has an overvoltage protection circuit for an AC voltage as an embodiment.
  • the power supply is a DC power supply, or a DC power supply unit that rectifies the AC power supply in the device.
  • each component may be replaced from the AC specification to the DC specification and provided on the downstream side of the DC power supply unit.
  • the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches a predetermined second threshold value, but it may be cut off when the overvoltage state has passed a predetermined duration. Good.
  • the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches a predetermined second threshold, but a device voltage detector 37 for detecting the voltage V applied to the device is further provided.
  • the voltage V may be cut off when it reaches a predetermined third threshold value.
  • FIG. 23 is a circuit diagram of an apparatus including an overvoltage protection circuit 150 according to another modification.
  • FIG. 24 is a graph showing changes in voltage V when the impedance is only resistance. 23 and 24, the variable impedance circuit 120 is normally connected to the low impedance element 121 at the contact point of the changeover switch 123 in the variable impedance circuit 120. Since the impedance Z 1 of the low impedance element 121 is 0 or a value close to 0, the voltage V ⁇ Vac is applied to the device 30.
  • the controller 40 uses the low impedance element 121 of the variable impedance circuit 120 to maintain the impedance Z 1 even when the voltage Vac of the commercial power supply 90 exceeds the normal value V 0 .
  • control unit 40 operates the changeover switch 123 to connect the contact point to the high impedance element 122.
  • control unit 40 maintains the state in which the contact of the changeover switch 123 is connected to the high impedance element 122. However, if the overvoltage state continues, the control unit 40 increases the voltage Vac of the commercial power supply 90 as shown in FIG. Along with this, the voltage V applied to the device 30 also increases.
  • the control unit 40 shuts off the power supply line 901 via the second switch 12. As a result, the device 30 can be protected, and power consumption and temperature rise in the variable impedance circuit 120 can be stopped.
  • control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 sets the impedance element of the variable impedance circuit 120 to a high impedance Switching from element 122 to low impedance element 121 returns impedance Z 2 to impedance Z 1 . Further, the second switch 12 is turned on and the power supply line 901 is connected to return to the normal operation.
  • the voltage detector and the second switch of the ninth embodiment are changed to be provided between the commercial power supply 90 and the DC power supply unit 80, but only the voltage detector is used as the commercial power supply. 90 and the DC power supply unit 80 may be provided.
  • the switch 11 in the first embodiment is connected in series to the low impedance element 121 and the high impedance element 122, respectively.
  • a switch to be turned on may be switched according to the detection voltage.
  • the switch 71 in the third embodiment is connected in series to the low impedance element 171 and the high impedance element 172, and the voltage detector 83 A switch to be turned on may be switched according to the detection voltage.
  • the present invention is useful for equipment used in an area where power supply voltage is likely to fluctuate, such as a refrigeration apparatus.

Abstract

This invention addresses the problem of providing a small-form-factor, low-cost overvoltage protection circuit that protects equipment from momentary excessive voltages and a power conversion device provided with said overvoltage protection circuit. In said overvoltage protection circuit (50), normally, a switch (11) is on, closing a bypass circuit (35), so no power is consumed in an impedance circuit (20), preventing a voltage being applied to equipment (30) from decreasing by an amount equal to the voltage drop across said impedance circuit (20). When an overvoltage occurs, the switch (11) turns off such that the voltage applied to the equipment (30) is reduced by an amount equal to the voltage drop corresponding to the impedance (Z) of the impedance circuit (20), making it possible to protect said equipment (30) from the overvoltage. Also, a second switch (12) opens a power-supply line (901), stopping the impedance circuit (20) from consuming power. This makes it possible to prevent overheating of the impedance circuit (20) and reduce the power rating.

Description

過電圧保護回路、及びそれを備えた電力変換装置Overvoltage protection circuit and power conversion device including the same
　本発明は、過電圧保護回路、及びそれを備えた電力変換装置に関する。 The present invention relates to an overvoltage protection circuit and a power conversion device including the same.
　電源電圧の変動が起こり易い地域で使用される機器は、電圧上昇時の対策如何によっては、機器の故障を招く虞がある。それゆえ、特許文献１（特開２００９－２０７３２９号公報）に開示されているような過電圧保護回路が設けられる。この過電圧保護回路は、所定電圧以上のときにリレーで電源を遮断する構成である。 ∙ Equipment used in areas where power supply voltage is likely to fluctuate may cause equipment failure depending on the measures taken when the voltage rises. Therefore, an overvoltage protection circuit as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2009-207329) is provided. This overvoltage protection circuit is configured to shut off the power supply with a relay when the voltage is equal to or higher than a predetermined voltage.
　しかしながら、電源電圧が過大となるのに要する時間は極めて短く、上記リレーによる遮断では反応が遅く確実に保護することは困難である。特に半導体素子のような、過電圧に耐えうる時間が短いものについては、リレーによる遮断では保護ができない。また、瞬間的な過大電圧のためだけに半導体素子などの耐圧を高くすることは高コスト化、大型化を招来する。 However, the time required for the power supply voltage to become excessive is extremely short, and it is difficult to reliably protect with a slow response due to the interruption by the relay. In particular, a semiconductor element such as a semiconductor element that has a short time to withstand overvoltage cannot be protected by being interrupted by a relay. Further, increasing the breakdown voltage of a semiconductor element or the like only for an instantaneous excessive voltage leads to an increase in cost and size.
　そこで、本発明の課題は、瞬間的な過大電圧から機器を保護する小型・低コストの過電圧保護回路、及びそれを備えた電力変換装置を提供することにある。 Therefore, an object of the present invention is to provide a small-sized and low-cost overvoltage protection circuit that protects a device from a momentary excessive voltage, and a power conversion device including the same.
　本発明の第１観点に係る過電圧保護回路は、電源とその電源から電力を供給される機器との間に接続される過電圧保護回路であって、インピーダンス回路と、電圧検出器と、バイパス回路とを備えている。インピーダンス回路は、電源と機器とを結ぶ電源ライン上に機器と直列に接続される。電圧検出器は、電源の電圧を検出する。バイパス回路は、インピーダンス回路を迂回する回路である。また、バイパス回路は、バイパス回路を開閉するスイッチを有している。スイッチは、通常時はバイパス回路を閉じ、電圧検出器による検出値が所定の閾値を超えたときにバイパス回路を遮断する。 An overvoltage protection circuit according to a first aspect of the present invention is an overvoltage protection circuit connected between a power source and a device supplied with power from the power source, and includes an impedance circuit, a voltage detector, a bypass circuit, It has. The impedance circuit is connected in series with the device on a power line connecting the power source and the device. The voltage detector detects the voltage of the power supply. The bypass circuit is a circuit that bypasses the impedance circuit. The bypass circuit has a switch for opening and closing the bypass circuit. The switch normally closes the bypass circuit, and shuts off the bypass circuit when the value detected by the voltage detector exceeds a predetermined threshold value.
　この過電圧保護回路では、通常時はバイパス回路を閉じているので、インピーダンス回路で電力が消費されることはなく、機器への印加電圧がインピーダンスでの電圧降下分だけ低くなることも回避することができる。他方、過電圧時には、インピーダンス回路のインピーダンスの電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 In this overvoltage protection circuit, since the bypass circuit is normally closed, power is not consumed by the impedance circuit, and it is possible to avoid that the voltage applied to the device is lowered by the voltage drop due to the impedance. it can. On the other hand, at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop of the impedance of the impedance circuit, and the device can be protected from overvoltage.
　本発明の第２観点に係る過電圧保護回路は、第１観点に係る過電圧保護回路であって、電源ラインを開閉する第２スイッチをさらに備えている。第２スイッチは、通常時は電源ラインを導通状態にし、電圧検出器による検出値が所定の閾値を超えたとき、スイッチの動作後に電源ラインを遮断する。 The overvoltage protection circuit according to the second aspect of the present invention is the overvoltage protection circuit according to the first aspect, and further includes a second switch for opening and closing the power supply line. The second switch normally turns on the power supply line, and shuts off the power supply line after operation of the switch when the value detected by the voltage detector exceeds a predetermined threshold.
　この過電圧保護回路では、通常時はバイパス回路を閉じているので、インピーダンス回路で電力が消費されることはなく、機器への印加電圧がインピーダンス回路での電圧降下分だけ低くなることも回避することができる。 In this overvoltage protection circuit, since the bypass circuit is normally closed, no power is consumed in the impedance circuit, and it is also possible to avoid that the voltage applied to the device is lowered by the voltage drop in the impedance circuit. Can do.
　そして、過電圧時にスイッチが動作することによって、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 And, by operating the switch at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage.
　さらに、スイッチの動作後、第２スイッチが動作して電源ラインを遮断することによってインピーダンス回路での電力消費を止める。この結果、インピーダンスの過熱を抑制することができ、電力定格を小さくすることができる。 Furthermore, after the switch is operated, the second switch is operated to cut off the power line, thereby stopping the power consumption in the impedance circuit. As a result, impedance overheating can be suppressed and the power rating can be reduced.
　本発明の第３観点に係る過電圧保護回路は、第１観点に係る過電圧保護回路であって、電源ラインを開閉する第２スイッチをさらに備えている。第２スイッチは、通常時は電源ラインを導通状態にし、電圧検出器による検出値が所定の閾値を超えている時間が、所定の継続時間判定値よりも長くなったとき、スイッチの動作後に電源ラインを遮断する。 The overvoltage protection circuit according to the third aspect of the present invention is the overvoltage protection circuit according to the first aspect, and further includes a second switch for opening and closing the power supply line. The second switch normally turns on the power supply line, and when the time when the value detected by the voltage detector exceeds a predetermined threshold becomes longer than the predetermined duration determination value, Shut off the line.
　この過電圧保護回路では、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 In this overvoltage protection circuit, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage.
　さらに、スイッチの動作後、第２スイッチが動作して電源ラインを遮断することによってインピーダンス回路での電力消費を止める。この結果、インピーダンスの過熱を抑制することができ、電力定格を小さくすることができる。 Furthermore, after the switch is operated, the second switch is operated to cut off the power line, thereby stopping the power consumption in the impedance circuit. As a result, impedance overheating can be suppressed and the power rating can be reduced.
　本発明の第４観点に係る過電圧保護回路は、第１観点に係る過電圧保護回路であって、電源ラインを開閉する第２スイッチと、機器に印加される電圧を検出する機器電圧検出器をさらに備えている。第２スイッチは、通常時は電源ラインを導通状態にし、機器電圧検出器による検出値が所定の第３閾値を超えたとき、スイッチの動作後に電源ラインを遮断する。 An overvoltage protection circuit according to a fourth aspect of the present invention is the overvoltage protection circuit according to the first aspect, further comprising: a second switch that opens and closes a power supply line; and a device voltage detector that detects a voltage applied to the device. I have. The second switch normally turns on the power line, and shuts off the power line after the operation of the switch when the value detected by the device voltage detector exceeds a predetermined third threshold.
　この過電圧保護回路では、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 In this overvoltage protection circuit, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage.
　さらに、スイッチの動作後、第２スイッチが動作して電源ラインを遮断することによってインピーダンス回路での電力消費を止める。この結果、インピーダンスの過熱を抑制することができ、電力定格を小さくすることができる。 Furthermore, after the switch is operated, the second switch is operated to cut off the power line, thereby stopping the power consumption in the impedance circuit. As a result, impedance overheating can be suppressed and the power rating can be reduced.
　本発明の第５観点に係る過電圧保護回路は、電源とその電源から電力を供給される機器との間に接続される過電圧保護回路であって、可変インピーダンス回路と電圧検出器とを備えている。可変インピーダンス回路は、電源と機器とを結ぶ電源ライン上に機器と直列に接続されている。電圧検出器は、電源の電圧を検出する。また、可変インピーダンス回路は、電圧検出器による検出値が所定の閾値を超えたとき、インピーダンス値を通常時の値よりも大きくする。 An overvoltage protection circuit according to a fifth aspect of the present invention is an overvoltage protection circuit connected between a power supply and a device supplied with power from the power supply, and includes a variable impedance circuit and a voltage detector. . The variable impedance circuit is connected in series with the device on a power line connecting the power source and the device. The voltage detector detects the voltage of the power supply. Further, the variable impedance circuit makes the impedance value larger than the normal value when the value detected by the voltage detector exceeds a predetermined threshold value.
　この過電圧保護回路では、通常時はインピーダンス値が小さい値（０を含む）に設定されるので、可変インピーダンス回路での電力消費が抑制され、可変インピーダンス回路での電圧降下も小さく、機器への印加電圧が可変インピーダンス回路での電圧降下分だけ低くなることも抑制することができる。 In this overvoltage protection circuit, the impedance value is normally set to a small value (including 0), so the power consumption in the variable impedance circuit is suppressed, the voltage drop in the variable impedance circuit is small, and the application to the device It can also be suppressed that the voltage is lowered by the voltage drop in the variable impedance circuit.
　他方、過電圧時には、インピーダンス値が大きい値に設定されるので、可変インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 On the other hand, since the impedance value is set to a large value during overvoltage, the voltage applied to the device is reduced by the voltage drop in the variable impedance circuit, and the device can be protected from overvoltage.
　本発明の第６観点に係る過電圧保護回路は、第５観点に係る過電圧保護回路であって、可変インピーダンス回路が、インピーダンス値を電圧検出器による検出値の変化に応じて連続的に変化させる。 The overvoltage protection circuit according to the sixth aspect of the present invention is the overvoltage protection circuit according to the fifth aspect, and the variable impedance circuit continuously changes the impedance value according to the change in the detection value by the voltage detector.
　この過電圧保護回路では、過電圧時には、インピーダンス値が大きい値に設定されるので、可変インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 In this overvoltage protection circuit, since the impedance value is set to a large value at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop in the variable impedance circuit, and the device can be protected from the overvoltage.
　本発明の第７観点に係る過電圧保護回路は、第５観点に係る過電圧保護回路であって、可変インピーダンス回路が、インピーダンス値を電圧検出器による検出値の変化に応じて段階的に変化させる。 The overvoltage protection circuit according to the seventh aspect of the present invention is the overvoltage protection circuit according to the fifth aspect, and the variable impedance circuit changes the impedance value stepwise in accordance with the change of the detection value by the voltage detector.
　この過電圧保護回路では、過電圧時には、インピーダンス値が大きい値に設定されるので、可変インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 In this overvoltage protection circuit, since the impedance value is set to a large value at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop in the variable impedance circuit, and the device can be protected from the overvoltage.
　本発明の第８観点に係る過電圧保護回路は、第５観点に係る過電圧保護回路であって、可変インピーダンス回路が、複数のインピーダンス要素を選択的に使用している。複数のインピーダンス要素は、第１インピーダンス要素と第２インピーダンス要素とを含んでいる。第１インピーダンス要素は、第１インピーダンス値を有している。第２インピーダンス要素は、第１インピーダンス値よりも大きい第２インピーダンス値を有している。可変インピーダンス回路は、第１インピーダンス要素の使用時に電圧検出器による検出値が所定の閾値を超えたとき、使用するインピーダンス要素を第１インピーダンス要素から第２インピーダンス要素へ切り換える。 The overvoltage protection circuit according to the eighth aspect of the present invention is the overvoltage protection circuit according to the fifth aspect, and the variable impedance circuit selectively uses a plurality of impedance elements. The plurality of impedance elements includes a first impedance element and a second impedance element. The first impedance element has a first impedance value. The second impedance element has a second impedance value that is greater than the first impedance value. The variable impedance circuit switches the impedance element to be used from the first impedance element to the second impedance element when the value detected by the voltage detector exceeds a predetermined threshold value when the first impedance element is used.
　この過電圧保護回路では、通常時はインピーダンス値が小さい方の第１インピーダンス要素に接続されるので、インピーダンス回路での電力消費が抑制され、インピーダンス回路での電圧降下も小さく、機器への印加電圧がインピーダンス回路での電圧降下分だけ低くなることも抑制することができる。 In this overvoltage protection circuit, since it is normally connected to the first impedance element having the smaller impedance value, the power consumption in the impedance circuit is suppressed, the voltage drop in the impedance circuit is small, and the voltage applied to the device is reduced. It can also be suppressed that the voltage drops by the impedance circuit.
　他方、過電圧時には、インピーダンス値が大きい方の第２インピーダンス要素に接続されるので、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 On the other hand, at the time of overvoltage, since it is connected to the second impedance element having the larger impedance value, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from the overvoltage.
　本発明の第９観点に係る過電圧保護回路は、第５観点から第８観点のいずれか１つに係る過電圧保護回路であって、電源ラインを開閉する第２スイッチをさらに備えている。第２スイッチは、通常時は電源ラインを導通状態にし、電圧検出器による検出値が所定の第２閾値を超えたとき、電源ラインを遮断する。 The overvoltage protection circuit according to the ninth aspect of the present invention is the overvoltage protection circuit according to any one of the fifth to eighth aspects, and further includes a second switch that opens and closes the power supply line. The second switch normally turns on the power supply line, and shuts off the power supply line when the value detected by the voltage detector exceeds a predetermined second threshold.
　この過電圧保護回路では、第２スイッチが動作して電源ラインを遮断することによってインピーダンス回路での電力消費を止める。この結果、インピーダンスの過熱を抑制することができ、電力定格を小さくすることができる。 ∙ In this overvoltage protection circuit, the power consumption in the impedance circuit is stopped by operating the second switch and shutting off the power line. As a result, impedance overheating can be suppressed and the power rating can be reduced.
　本発明の第１０観点に係る過電圧保護回路は、第５観点から第８観点のいずれか１つに係る過電圧保護回路であって、電源ラインを開閉する第２スイッチをさらに備えている。第２スイッチは、通常時は電源ラインを導通状態にし、電圧検出器による検出値が所定の閾値を超えている時間が、所定の継続時間判定値よりも長くなったとき、電源ラインを遮断する。 The overvoltage protection circuit according to the tenth aspect of the present invention is the overvoltage protection circuit according to any one of the fifth to eighth aspects, and further includes a second switch that opens and closes the power supply line. The second switch normally turns on the power line, and shuts off the power line when the time when the value detected by the voltage detector exceeds a predetermined threshold becomes longer than a predetermined duration determination value. .
　この過電圧保護回路では、第２スイッチが動作して電源ラインを遮断することによってインピーダンス回路での電力消費を止める。この結果、インピーダンスの過熱を抑制することができ、電力定格を小さくすることができる。 ∙ In this overvoltage protection circuit, the power consumption in the impedance circuit is stopped by operating the second switch and shutting off the power line. As a result, impedance overheating can be suppressed and the power rating can be reduced.
　本発明の第１１観点に係る過電圧保護回路は、第５観点から第８観点のいずれか１つに係る過電圧保護回路であって、電源ラインを開閉する第２スイッチと、機器に印加される電圧を検出する機器電圧検出器とをさらに備えている。第２スイッチは、通常時は電源ラインを導通状態にし、機器電圧検出器による検出値が所定の第３閾値を超えたとき、電源ラインを遮断する。 An overvoltage protection circuit according to an eleventh aspect of the present invention is the overvoltage protection circuit according to any one of the fifth to eighth aspects, the second switch for opening and closing the power supply line, and the voltage applied to the device And a device voltage detector. The second switch normally turns on the power line, and shuts off the power line when the value detected by the device voltage detector exceeds a predetermined third threshold.
　この過電圧保護回路では、第２スイッチが動作して電源ラインを遮断することによってインピーダンス回路での電力消費を止める。この結果、インピーダンスの過熱を抑制することができ、電力定格を小さくすることができる。 ∙ In this overvoltage protection circuit, the power consumption in the impedance circuit is stopped by operating the second switch and shutting off the power line. As a result, impedance overheating can be suppressed and the power rating can be reduced.
　本発明の第１２観点に係る過電圧保護回路は、第１観点から第１１観点のいずれか１つに係る過電圧保護回路であって、電源がＡＣ電源である。 The overvoltage protection circuit according to the twelfth aspect of the present invention is the overvoltage protection circuit according to any one of the first to eleventh aspects, and the power supply is an AC power supply.
　この過電圧保護回路では、ＡＣ電源からの供給電圧が過大電圧であっても、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減される。それゆえ、短時間の過大電圧からの保護だけのために機器の整流部の定格を高く設計する必要がなく、合理的である。 In this overvoltage protection circuit, even if the supply voltage from the AC power supply is an excessive voltage, the voltage applied to the device is reduced by the voltage drop in the impedance circuit. Therefore, it is not necessary to design the rating of the rectification unit of the device high only for protection from an excessive voltage for a short time, and it is reasonable.
　本発明の第１３観点に係る過電圧保護回路は、第１観点から第１１観点のいずれか１つに係る過電圧保護回路であって、電源がＤＣ電源である。 The overvoltage protection circuit according to the thirteenth aspect of the present invention is the overvoltage protection circuit according to any one of the first to eleventh aspects, and the power source is a DC power source.
　この過電圧保護回路では、交流を入り切りするスイッチは双方向性を必要とするが、ＤＣ電源の下流側に配置されるスイッチは片方向スイッチでよいので、スイッチの低コスト化を図ることができる。 In this overvoltage protection circuit, the switch for turning on and off the alternating current needs bidirectionality, but the switch arranged on the downstream side of the DC power supply may be a one-way switch, so that the cost of the switch can be reduced.
　本発明の第１４観点に係る電力変換装置は、コンバータ回路と、インバータ回路と、第１観点から第１０観点のいずれか一つの過電圧保護回路とを備えている。コンバータ回路は、交流電源に接続され、交流電圧を直流電圧に変換する。インバータ回路は、直流電圧を交流電圧に変換する。 The power conversion device according to the fourteenth aspect of the present invention includes a converter circuit, an inverter circuit, and any one of the overvoltage protection circuits according to the first to tenth aspects. The converter circuit is connected to an AC power source and converts an AC voltage into a DC voltage. The inverter circuit converts a DC voltage into an AC voltage.
　この電力変換装置では、過電圧保護回路が、コンバータ回路を過渡的に印加される過大交流電圧から保護し、又はインバータ回路を過渡的に印加される過大直流電圧から保護することができる。 In this power converter, the overvoltage protection circuit can protect the converter circuit from excessively applied alternating voltage or the inverter circuit from transiently applied excessive DC voltage.
　本発明の第１観点に係る過電圧保護回路では、通常時はバイパス回路を閉じているので、インピーダンス回路で電力が消費されることはなく、機器への印加電圧がインピーダンスでの電圧降下分だけ低くなることも回避することができる。他方、過電圧時には、インピーダンス回路のインピーダンスの電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 In the overvoltage protection circuit according to the first aspect of the present invention, since the bypass circuit is normally closed, power is not consumed by the impedance circuit, and the voltage applied to the device is lowered by the voltage drop at the impedance. It can also be avoided. On the other hand, at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop of the impedance of the impedance circuit, and the device can be protected from overvoltage.
　本発明の第２観点に係る過電圧保護回路では、通常時はバイパス回路を閉じているので、インピーダンス回路で電力が消費されることはなく、機器への印加電圧がインピーダンス回路での電圧降下分だけ低くなることも回避することができる。 In the overvoltage protection circuit according to the second aspect of the present invention, since the bypass circuit is normally closed, power is not consumed in the impedance circuit, and the voltage applied to the device is only the voltage drop in the impedance circuit. Lowering can also be avoided.
　そして、過電圧時にスイッチが動作することによって、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 And, by operating the switch at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage.
　さらに、スイッチの動作後、第２スイッチが動作して電源ラインを遮断することによってインピーダンス回路での電力消費を止める。この結果、インピーダンスの過熱を抑制することができ、電力定格を小さくすることができる。 Furthermore, after the switch is operated, the second switch is operated to cut off the power line, thereby stopping the power consumption in the impedance circuit. As a result, impedance overheating can be suppressed and the power rating can be reduced.
　本発明の第３観点、及び第４観点に係る過電圧保護回路では、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。さらに、スイッチの動作後、第２スイッチが動作して電源ラインを遮断することによってインピーダンス回路での電力消費を止める。この結果、インピーダンスの電力定格を小さくすることができる。 In the overvoltage protection circuit according to the third and fourth aspects of the present invention, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage. Further, after the switch is operated, the second switch is operated to cut off the power supply line, thereby stopping the power consumption in the impedance circuit. As a result, the power rating of the impedance can be reduced.
　本発明の第５観点に係る過電圧保護回路では、通常時はインピーダンス値が小さい値（０を含む）に設定されるので、インピーダンス回路での電力消費が抑制され、インピーダンス回路での電圧降下も小さく、機器への印加電圧がインピーダンス回路での電圧降下分だけ低くなることも抑制することができる。 In the overvoltage protection circuit according to the fifth aspect of the present invention, since the impedance value is normally set to a small value (including 0), the power consumption in the impedance circuit is suppressed, and the voltage drop in the impedance circuit is also small. It is also possible to suppress the voltage applied to the device from being lowered by the voltage drop in the impedance circuit.
　他方、過電圧時には、インピーダンス値が大きい値に設定されるので、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 On the other hand, since the impedance value is set to a large value during overvoltage, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from overvoltage.
　本発明の第６観点、及び第７観点に係る過電圧保護回路では、過電圧時には、インピーダンス値が大きい値に設定されるので、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 In the overvoltage protection circuit according to the sixth aspect and the seventh aspect of the present invention, since the impedance value is set to a large value at the time of overvoltage, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, Equipment can be protected from overvoltage.
　本発明の第８観点に係る過電圧保護回路では、通常時はインピーダンス値が小さい方の第１インピーダンス要素に接続されるので、インピーダンス回路での電力消費が抑制され、インピーダンス回路での電圧降下も小さく、機器への印加電圧がインピーダンス回路での電圧降下分だけ低くなることも抑制することができる。 In the overvoltage protection circuit according to the eighth aspect of the present invention, since it is normally connected to the first impedance element having the smaller impedance value, the power consumption in the impedance circuit is suppressed, and the voltage drop in the impedance circuit is also small. It is also possible to suppress the voltage applied to the device from being lowered by the voltage drop in the impedance circuit.
　他方、過電圧時には、インピーダンス値が大きい方の第２インピーダンス要素に接続されるので、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減され、機器を過電圧から保護することができる。 On the other hand, at the time of overvoltage, since it is connected to the second impedance element having the larger impedance value, the voltage applied to the device is reduced by the voltage drop in the impedance circuit, and the device can be protected from the overvoltage.
　本発明の第９観点から第１１観点のいずれか１つに係る過電圧保護回路では、第２スイッチが動作して電源ラインを遮断することによってインピーダンス回路での電力消費を止める。この結果、インピーダンスの過熱を抑制することができ、電力定格を小さくすることができる。 In the overvoltage protection circuit according to any one of the ninth to eleventh aspects of the present invention, the power consumption in the impedance circuit is stopped by operating the second switch to cut off the power line. As a result, impedance overheating can be suppressed and the power rating can be reduced.
　本発明の第１２観点に係る過電圧保護回路では、ＡＣ電源からの供給電圧が過大電圧であっても、インピーダンス回路での電圧降下分だけ機器に印加される電圧が低減される。それゆえ、短時間の過大電圧からの保護だけのために機器の電圧定格を高く設計する必要がなく、合理的である。 In the overvoltage protection circuit according to the twelfth aspect of the present invention, even if the supply voltage from the AC power supply is an excessive voltage, the voltage applied to the device is reduced by the voltage drop in the impedance circuit. Therefore, it is not necessary to design the equipment with a high voltage rating only for protection from an excessive voltage for a short time, which is reasonable.
　本発明の第１３観点に係る過電圧保護回路では、交流を入り切りするスイッチは双方向性を必要とするが、ＤＣ電源の下流側に配置されるスイッチは片方向スイッチでよいので、スイッチの低コスト化を図ることができる。 In the overvoltage protection circuit according to the thirteenth aspect of the present invention, the switch for turning on and off the alternating current needs bidirectionality, but the switch arranged on the downstream side of the DC power supply may be a one-way switch, so that the low cost of the switch Can be achieved.
　本発明の第１４観点に係る電力変換装置では、過電圧保護回路が、コンバータ回路を過渡的に印加される過大交流電圧から保護し、又はインバータ回路を過渡的に印加される過大直流電圧から保護することができる。 In the power conversion device according to the fourteenth aspect of the present invention, the overvoltage protection circuit protects the converter circuit from excessively applied alternating voltage or protects the inverter circuit from transiently applied excessive DC voltage. be able to.
本発明の第１実施形態に係る過電圧保護回路を備えた装置の回路図。The circuit diagram of the apparatus provided with the overvoltage protection circuit which concerns on 1st Embodiment of this invention. 電圧検出器の回路図。The circuit diagram of a voltage detector. インピーダンスが抵抗のみの場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance is only resistance. インピーダンスがインダクタンス成分を含む場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance contains an inductance component. 本発明の第２実施形態に係る過電圧保護回路を備えた装置の回路図。The circuit diagram of the apparatus provided with the overvoltage protection circuit which concerns on 2nd Embodiment of this invention. インピーダンスが抵抗のみの場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance is only resistance. 本発明の第３実施形態に係る過電圧保護回路を備えた電力変換装置の回路図。The circuit diagram of the power converter device provided with the overvoltage protection circuit which concerns on 3rd Embodiment of this invention. 本発明の第４実施形態に係る過電圧保護回路を備えた電力変換装置の回路図。The circuit diagram of the power converter device provided with the overvoltage protection circuit which concerns on 4th Embodiment of this invention. インピーダンスが抵抗のみの場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance is only resistance. インピーダンスが抵抗のみの場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance is only resistance. その他の変形例に係る過電圧保護回路を備えた電力変換装置の回路図。The circuit diagram of the power converter device provided with the overvoltage protection circuit which concerns on another modification. 本発明の第５実施形態に係る過電圧保護回路を備えた装置の回路図。The circuit diagram of the apparatus provided with the overvoltage protection circuit which concerns on 5th Embodiment of this invention. インピーダンスが可変抵抗のみで且つインピーダンスが連続的に増加する場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance is only a variable resistance and an impedance increases continuously. インピーダンスが可変抵抗のみで且つインピーダンスが段階的に増加する場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance is only a variable resistance and an impedance increases in steps. 本発明の第６実施形態に係る過電圧保護回路を備えた装置の回路図。The circuit diagram of the apparatus provided with the overvoltage protection circuit which concerns on 6th Embodiment of this invention. インピーダンスが抵抗のみの場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance is only resistance. 本発明の第７実施形態に係る過電圧保護回路を備えた装置の回路図。The circuit diagram of the apparatus provided with the overvoltage protection circuit which concerns on 7th Embodiment of this invention. インピーダンスが抵抗のみの場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance is only resistance. 本発明の第８実施形態に係る過電圧保護回路を備えた装置の回路図。The circuit diagram of the apparatus provided with the overvoltage protection circuit which concerns on 8th Embodiment of this invention. インピーダンスが抵抗のみの場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance is only resistance. 本発明の第９実施形態に係る過電圧保護回路を備えた電力変換装置の回路図。The circuit diagram of the power converter device provided with the overvoltage protection circuit which concerns on 9th Embodiment of this invention. 本発明の第１０実施形態に係る過電圧保護回路を備えた電力変換装置の回路図。The circuit diagram of the power converter device provided with the overvoltage protection circuit which concerns on 10th Embodiment of this invention. 他の変形例に係る過電圧保護回路を備えた装置の回路図。The circuit diagram of the apparatus provided with the overvoltage protection circuit which concerns on another modification. インピーダンスが抵抗のみの場合の電圧Ｖの変化を示すグラフ。The graph which shows the change of the voltage V when an impedance is only resistance.
　以下、図面を参照しながら、本発明の実施形態について説明する。なお、以下の実施形態は、本発明の具体例であって、本発明の技術的範囲を限定するものではない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are specific examples of the present invention and do not limit the technical scope of the present invention.
　＜第１実施形態＞
　（１）過電圧保護回路５０の構成
　図１は、本発明の第１実施形態に係る過電圧保護回路５０を備えた装置の回路図である。図１において、機器３０は、商用電源９０から一対の電源ライン９０１，９０２を介して電力供給されている。過電圧保護回路５０は、商用電源９０と機器３０との間に接続されている。 <First Embodiment>
(1) Configuration of Overvoltage Protection Circuit 50 FIG. 1 is a circuit diagram of a device including an overvoltage protection circuit 50 according to the first embodiment of the present invention. In FIG. 1, the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902. The overvoltage protection circuit 50 is connected between the commercial power supply 90 and the device 30.
　過電圧保護回路５０は、インピーダンス回路２０と、電圧検出器３３と、バイパス回路３５を含んでいる。 The overvoltage protection circuit 50 includes an impedance circuit 20, a voltage detector 33, and a bypass circuit 35.
　（２）過電圧保護回路５０の詳細構成
　（２－１）インピーダンス回路２０
　インピーダンス回路２０は、当該回路における電圧と電流との比であるインピーダンスがＺとなるように構成された回路である。 (2) Detailed configuration of overvoltage protection circuit 50 (2-1) Impedance circuit 20
The impedance circuit 20 is a circuit configured such that an impedance that is a ratio of a voltage and a current in the circuit is Z.
　インピーダンス回路２０は、電源ライン９０２上で、商用電源９０と機器３０との間に接続されている。 The impedance circuit 20 is connected between the commercial power supply 90 and the device 30 on the power supply line 902.
　（２－２）電圧検出器３３
　電圧検出器３３は、交流電圧検出回路によって構成されている。交流電圧検出回路は、多様であり、使用条件によって適宜採用される。例えば、図２は一般的な電圧検出器３３の回路図である。図２において、電圧検出器３３は、変圧回路３３１、コンバータ回路３３２とで構成されている。 (2-2) Voltage detector 33
The voltage detector 33 is configured by an AC voltage detection circuit. There are various AC voltage detection circuits, and they are appropriately adopted depending on use conditions. For example, FIG. 2 is a circuit diagram of a general voltage detector 33. In FIG. 2, the voltage detector 33 includes a transformer circuit 331 and a converter circuit 332.
　変圧回路３３１は、入力側に位置し、一次側巻線３３１ａと二次側巻線３３１ｂとからなる。 The transformer circuit 331 is located on the input side and includes a primary winding 331a and a secondary winding 331b.
　コンバータ回路３３２は、整流ダイオードで構成される整流部３３２ａと、平滑コンデンサ３３２ｂとが並列接続された回路である。 The converter circuit 332 is a circuit in which a rectifying unit 332a composed of a rectifying diode and a smoothing capacitor 332b are connected in parallel.
　電圧検出器３３では、変圧回路３３１に交流電圧が印加されると、交流電圧は変圧回路３３１によって変圧される。そして、二次側巻線３３１ｂの両端電圧がコンバータ回路３３２に入力される。 In the voltage detector 33, when an AC voltage is applied to the transformer circuit 331, the AC voltage is transformed by the transformer circuit 331. Then, the voltage across the secondary winding 331 b is input to the converter circuit 332.
　コンバータ回路３３２に入力された変圧後の交流電圧は、整流部３３２ａで直流電圧に変換され、平滑コンデンサ３３２ｂで平滑化される。この平滑化された直流電圧が制御部４０に入力される。すなわち、一次側巻線３３１ａに印加される電圧に応じた直流電圧が、制御部４０に入力されることになる。 The AC voltage after transformation input to the converter circuit 332 is converted into a DC voltage by the rectifying unit 332a and smoothed by the smoothing capacitor 332b. This smoothed DC voltage is input to the control unit 40. That is, a DC voltage corresponding to the voltage applied to the primary winding 331a is input to the control unit 40.
　（２－３）バイパス回路３５
　バイパス回路３５は、インピーダンス回路２０に並列接続されており、インピーダンス回路２０を迂回する回路である。バイパス回路３５は、スイッチ１１を有している。スイッチ１１は、バイパス回路３５を開閉する。ここで、バイパス回路３５を開閉するとは、バイパス回路３５を導通又は遮断して非導通にすることである。 (2-3) Bypass circuit 35
The bypass circuit 35 is connected to the impedance circuit 20 in parallel and bypasses the impedance circuit 20. The bypass circuit 35 has a switch 11. The switch 11 opens and closes the bypass circuit 35. Here, opening and closing the bypass circuit 35 means making the bypass circuit 35 conductive or non-conductive to make it non-conductive.
　（２－４）スイッチ１１
　スイッチ１１は、通常時はバイパス回路３５を閉、つまり導通状態にしておく。なぜなら、通常時にバイパス回路３５を開（非導通状態）にしておくと、インピーダンス回路２０が常に接続された状態となって常に電力消費される上に、機器３０への印加電圧がインピーダンス回路２０のインピーダンスＺの電圧降下分だけ低くなるからである。 (2-4) Switch 11
The switch 11 normally closes the bypass circuit 35, that is, keeps it conductive. This is because if the bypass circuit 35 is left open (non-conducting state) during normal operation, the impedance circuit 20 is always connected and power is always consumed, and the voltage applied to the device 30 is applied to the impedance circuit 20. This is because the voltage drops by the voltage drop of the impedance Z.
　他方、過電圧時は機器３０を保護するためにバイパス回路３５を素早く開にしてインピーダンス回路２０を接続し、商用電源９０―機器３０―インピーダンス回路２０―商用電源９０という閉回路を構成する必要がある。そのため、スイッチ１１には、高速動作が求められる。 On the other hand, in order to protect the device 30 at the time of overvoltage, it is necessary to quickly open the bypass circuit 35 and connect the impedance circuit 20 to form a closed circuit of commercial power supply 90-device 30-impedance circuit 20-commercial power supply 90. . Therefore, the switch 11 is required to operate at high speed.
　スイッチ１１としては、トライアック、双方向に導通させるように接続したＭＯＳＦＥＴなどが採用される。本実施形態では、フォトトライアックカプラが採用されている。 As the switch 11, a triac, a MOSFET connected so as to conduct in both directions, or the like is employed. In the present embodiment, a phototriac coupler is employed.
　図１に示すように、スイッチ１１は、入力側（Ａ１－Ａ２間）に発光ダイオード１１ａが設けられ、出力側（Ｂ１－Ｂ２間）にフォトトライアック１１ｂが設けられている。フォトトライアック１１ｂの等価回路は、２つのフォトサイリスタ１１１，１１２を互いに逆方向に並列接続した構成である。 As shown in FIG. 1, the switch 11 is provided with a light emitting diode 11a on the input side (between A1 and A2) and a phototriac 11b on the output side (between B1 and B2). The equivalent circuit of the phototriac 11b has a configuration in which two photothyristors 111 and 112 are connected in parallel in opposite directions.
　発光ダイオード１１ａのアノードＡ１は抵抗Ｒ１を介して電源Ｖｃに接続されている。また、発光ダイオード１１ａのカソードＡ２は信号線を介して制御部４０に接続されている。 The anode A1 of the light emitting diode 11a is connected to the power source Vc via the resistor R1. The cathode A2 of the light emitting diode 11a is connected to the control unit 40 through a signal line.
　フォトトライアック１１ｂの第１アノードＢ１は、電源ライン９０２のうちのインピーダンス回路２０と機器３０との間に接続されている。また、フォトトライアック１１ｂの第２アノードＢ２は電源ライン９０２にうちのインピーダンス回路２０と商用電源９０との間に接続されている。 The first anode B1 of the phototriac 11b is connected between the impedance circuit 20 in the power supply line 902 and the device 30. The second anode B2 of the phototriac 11b is connected to the power supply line 902 between the impedance circuit 20 and the commercial power supply 90.
　発光ダイオード１１ａは電流が流れると発光する。フォトトライアック１１ｂは、第１アノードＢ１の電位が第２アノードＢ２の電位より大きい状態で発光ダイオード１１ａからの光を受けるとフォトサイリスタ１１１がオン状態になる。他方、第１アノードＢ１の電位が第２アノードＢ２の電位より小さい状態で発光ダイオード１１ａからの光を受けるとフォトサイリスタ１１２がオン状態になる。 The light emitting diode 11a emits light when a current flows. When the phototriac 11b receives light from the light emitting diode 11a in a state where the potential of the first anode B1 is higher than the potential of the second anode B2, the photothyristor 111 is turned on. On the other hand, when light from the light emitting diode 11a is received in a state where the potential of the first anode B1 is smaller than the potential of the second anode B2, the photothyristor 112 is turned on.
　このように、フォトトライアック１１ｂは双方向の印加電圧に対して動作する双方向素子であり、しかも高速で動作するので、双方向の高速スイッチとして利用される。 Thus, the phototriac 11b is a bidirectional element that operates with respect to a bidirectional applied voltage, and also operates at a high speed, so that it is used as a bidirectional high-speed switch.
　なお、双方向の高速スイッチとしては、フォトトライアックだけに限定されるものではなく、通常のトライアックや、双方向に導通させるように接続したＭＯＳＦＥＴなどを採用してもよい。別の形態の高速スイッチを用いる場合には、そのスイッチの形態に応じた駆動回路が適宜使用される。 Note that the bidirectional high-speed switch is not limited to the photo triac, but a normal triac or a MOSFET connected so as to conduct in both directions may be employed. When another form of high-speed switch is used, a drive circuit corresponding to the form of the switch is appropriately used.
　また、スイッチ１１の動作制御、つまり発光ダイオード１１ａへの通電制御は制御部４０が行う。 Further, the control unit 40 performs operation control of the switch 11, that is, energization control to the light emitting diode 11a.
　（３）過電圧保護回路５０の動作
　図３は、機器３０のインピーダンスが抵抗成分のみであり、インピーダンスＺが抵抗のみの場合の電圧Ｖの変化を示すグラフである。図１及び図３において、通常時、バイパス回路３５はスイッチ１１が閉じて導通状態であるので、機器３０には電圧Ｖ＝Ｖａｃが印加されている。 (3) Operation of Overvoltage Protection Circuit 50 FIG. 3 is a graph showing changes in the voltage V when the impedance of the device 30 is only a resistance component and the impedance Z is only a resistance. In FIG. 1 and FIG. 3, the voltage V = Vac is applied to the device 30 because the bypass circuit 35 is normally in a conductive state with the switch 11 closed.
　商用電源９０の電圧Ｖａｃが急激に増加し、制御部４０が電圧検出器３３から出力される電圧が閾値を超えたと判定したとき、制御部４０はスイッチ１１の発光ダイオード１１ａへの通電を停止し、フォトトライアック１１ｂをオフさせる。なお、機器３０を保護するため、スイッチ１１には高速動作が求められる。 When the voltage Vac of the commercial power supply 90 suddenly increases and the control unit 40 determines that the voltage output from the voltage detector 33 has exceeded the threshold, the control unit 40 stops energizing the light emitting diode 11a of the switch 11. Then, the photo triac 11b is turned off. In order to protect the device 30, the switch 11 is required to operate at high speed.
　その結果、商用電源９０―機器３０―インピーダンス回路２０―商用電源９０という閉回路が構成される。このとき、機器３０には電圧Ｖ＝Ｖａｃ－Ｖｚしか印加されない。その結果、機器３０が過電圧から保護される。なお、スイッチ１１のオフ後も電圧Ｖａｃが上昇している場合は、その上昇に伴って電圧Ｖも上昇する。 As a result, a closed circuit of the commercial power source 90 -the device 30 -the impedance circuit 20 -the commercial power source 90 is configured. At this time, only the voltage V = Vac−Vz is applied to the device 30. As a result, the device 30 is protected from overvoltage. If the voltage Vac is increased even after the switch 11 is turned off, the voltage V increases as the voltage Vac increases.
　図４は、インピーダンスＺがインダクタンス成分を含む場合の電圧Ｖの変化を示すグラフである。図４において、通常時、機器３０には電圧Ｖ＝Ｖａｃが印加されている。商用電源９０の電圧Ｖａｃが、例えば、図３の最大過電圧値と同じ値まで瞬間的に変動し、制御部４０がスイッチ１１をオフさせたとき、スイッチ１１のオフ後の電圧Ｖの上昇は、インピーダンスＺが抵抗だけの場合に比べて、緩やかに上昇する。 FIG. 4 is a graph showing a change in the voltage V when the impedance Z includes an inductance component. In FIG. 4, the voltage V = Vac is applied to the device 30 at the normal time. For example, when the voltage Vac of the commercial power supply 90 fluctuates instantaneously to the same value as the maximum overvoltage value in FIG. 3 and the control unit 40 turns off the switch 11, the increase in the voltage V after the switch 11 is turned off is Compared to the case where the impedance Z is only a resistance, it rises more slowly.
　したがって、電源電圧の変動が起こり易く、過電圧が長く続く地域には、インピーダンスＺがインダクタンス成分を含むものを採用するのが好ましい。 Therefore, it is preferable to employ the one in which the impedance Z includes an inductance component in an area where the power supply voltage is likely to fluctuate and the overvoltage continues for a long time.
　商用電源９０の電圧Ｖａｃが下がり、電圧検出器３３から出力される電圧が復帰のための閾値よりも下がったと制御部４０が判定したとき、制御部４０はスイッチ１１の発光ダイオード１１ａへ通電し、フォトトライアック１１ｂをオンさせる。これにより、通常の動作に復帰する。 When the control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 energizes the light emitting diode 11a of the switch 11, The photo triac 11b is turned on. As a result, the normal operation is restored.
　（４）第１実施形態の特徴
　（４－１）
　過電圧保護回路５０では、通常時はスイッチ１１をオンにしてバイパス回路３５を閉じているので、インピーダンス回路２０で電力が消費されることはなく、機器３０への印加電圧がインピーダンス回路２０での電圧降下分だけ低くなることも回避することができる。 (4) Features of the first embodiment (4-1)
In the overvoltage protection circuit 50, since the switch 11 is normally turned on and the bypass circuit 35 is closed, no power is consumed in the impedance circuit 20, and the voltage applied to the device 30 is the voltage applied to the impedance circuit 20. It is also possible to avoid lowering by the amount of descent.
　（４－２）
　また、過電圧時には、スイッチ１１がオフすることによって、インピーダンス回路２０のインピーダンスＺの電圧降下分だけ機器３０に印加される電圧が低減され、機器３０を過電圧から保護することができる。 (4-2)
Further, when the voltage is overvoltage, the switch 11 is turned off, so that the voltage applied to the device 30 is reduced by the voltage drop of the impedance Z of the impedance circuit 20, and the device 30 can be protected from the overvoltage.
　（４－３）
　商用電源９０からの供給電圧が過大電圧であっても、インピーダンス回路２０での電圧降下分だけ機器３０に印加される電圧が低減される。それゆえ、短時間の過大電圧からの保護だけのために機器の電圧定格を高く設計する必要がなく、合理的である。 (4-3)
Even if the supply voltage from the commercial power supply 90 is an excessive voltage, the voltage applied to the device 30 is reduced by the voltage drop in the impedance circuit 20. Therefore, it is not necessary to design the equipment with a high voltage rating only for protection from an excessive voltage for a short time, which is reasonable.
　＜第２実施形態＞
　（１）過電圧保護回路５０の構成
　図５は、本発明の第２実施形態に係る過電圧保護回路５０を備えた装置の回路図である。図５において、機器３０は、商用電源９０から一対の電源ライン９０１，９０２を介して電力供給されている。過電圧保護回路５０は、商用電源９０と機器３０との間に接続されている。 Second Embodiment
(1) Configuration of Overvoltage Protection Circuit 50 FIG. 5 is a circuit diagram of a device including an overvoltage protection circuit 50 according to the second embodiment of the present invention. In FIG. 5, the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902. The overvoltage protection circuit 50 is connected between the commercial power supply 90 and the device 30.
　過電圧保護回路５０は、インピーダンス回路２０と、電圧検出器３３と、バイパス回路３５と、第２スイッチ１２とを含んでいる。 The overvoltage protection circuit 50 includes an impedance circuit 20, a voltage detector 33, a bypass circuit 35, and the second switch 12.
　（２）過電圧保護回路５０の詳細構成
　第２実施形態は、第１実施形態に第２スイッチ１２が追加された形態であり、インピーダンス回路２０、電圧検出器３３、及びバイパス回路３５については同様のものを採用している。したがって、ここでは第２スイッチ１２についてのみを説明する。 (2) Detailed Configuration of Overvoltage Protection Circuit 50 In the second embodiment, the second switch 12 is added to the first embodiment, and the impedance circuit 20, the voltage detector 33, and the bypass circuit 35 are the same. The thing is adopted. Therefore, only the second switch 12 will be described here.
　（２－１）第２スイッチ１２
　第２スイッチ１２は、電源ライン９０１を開閉する。ここで、電源ライン９０１を開閉するとは、電源ライン９０１を導通又は遮断して非導通にすることである。 (2-1) Second switch 12
The second switch 12 opens and closes the power line 901. Here, opening and closing the power supply line 901 means that the power supply line 901 is turned on or off to make it non-conductive.
　第２スイッチ１２は、通常時は電源ライン９０１を閉、つまり導通状態にしておく。他方、過電圧時には、スイッチ１１がオフして、商用電源９０―機器３０―インピーダンス回路２０―商用電源９０という閉回路が構成され、機器３０の保護動作が行われた後に、第２スイッチ１２がオフして電源ライン９０１を遮断する。 The second switch 12 normally closes the power supply line 901, that is, keeps it conductive. On the other hand, at the time of overvoltage, the switch 11 is turned off to form a closed circuit of the commercial power supply 90-the device 30-the impedance circuit 20-the commercial power supply 90, and after the protection operation of the device 30 is performed, the second switch 12 is turned off. Then, the power line 901 is shut off.
　電源ライン９０１を遮断する目的は、インピーダンス回路２０での電力消費を止めるためであり、インピーダンス回路２０の電力定格を小さくすることができ、低コスト化を図ることができる。 The purpose of cutting off the power supply line 901 is to stop the power consumption in the impedance circuit 20, the power rating of the impedance circuit 20 can be reduced, and the cost can be reduced.
　第２スイッチ１２は、スイッチ１１のような高速性は求められないので、本実施形態ではリレー回路が採用されている。 Since the second switch 12 is not required to be as fast as the switch 11, a relay circuit is employed in this embodiment.
　図５に示すように、第２スイッチ１２は、電源ライン９０１を開閉するリレー接点１２ａと、リレー接点１２ａを動作させるリレーコイル１２ｂと、リレーコイル１２ｂへの通電と非通電とを行うトランジスタ１２ｃとを含んでいる。リレーコイル１２ｂの一端は、電源Ｖｂの正極に接続され、他端はトランジスタ１２ｃのコレクタ側に接続されている。制御部４０は、トランジスタ１２ｃのベース電流の有無を切り換えて、コレクタとエミッタ間をオンオフし、リレーコイル１２ｂへの通電と非通電を行う。 As shown in FIG. 5, the second switch 12 includes a relay contact 12a for opening and closing the power supply line 901, a relay coil 12b for operating the relay contact 12a, and a transistor 12c for energizing and de-energizing the relay coil 12b. Is included. One end of the relay coil 12b is connected to the positive electrode of the power source Vb, and the other end is connected to the collector side of the transistor 12c. The control unit 40 switches the presence / absence of the base current of the transistor 12c, turns on / off the collector and the emitter, and energizes and de-energizes the relay coil 12b.
　（３）過電圧保護回路５０の動作
　図６は、インピーダンスＺが抵抗のみの場合の電圧Ｖの変化を示すグラフである。図５及び図６において、通常時、バイパス回路３５はスイッチ１１が閉じて導通状態であり、且つ第２スイッチ１２は電源ライン９０１を導通状態にしているので、機器３０には電圧Ｖ＝Ｖａｃが印加されている。 (3) Operation of Overvoltage Protection Circuit 50 FIG. 6 is a graph showing changes in the voltage V when the impedance Z is only a resistance. 5 and 6, normally, the bypass circuit 35 is in the conductive state with the switch 11 closed, and the second switch 12 has the power supply line 901 in the conductive state, so that the voltage V = Vac is applied to the device 30. Applied.
　商用電源９０の電圧Ｖａｃが急激に増加し、制御部４０が電圧検出器３３から出力される電圧が閾値を超えたと判定したとき、制御部４０はスイッチ１１の発光ダイオード１１ａへの通電を停止し、フォトトライアック１１ｂをオフさせる。 When the voltage Vac of the commercial power supply 90 suddenly increases and the control unit 40 determines that the voltage output from the voltage detector 33 has exceeded the threshold, the control unit 40 stops energizing the light emitting diode 11a of the switch 11. Then, the photo triac 11b is turned off.
　その結果、商用電源９０―機器３０―インピーダンス回路２０―商用電源９０という閉回路が構成される。このとき、機器３０には電圧Ｖ＝Ｖａｃ－Ｖｚしか印加されない。その結果、機器３０が過電圧から保護される。 As a result, a closed circuit of the commercial power source 90 -the device 30 -the impedance circuit 20 -the commercial power source 90 is configured. At this time, only the voltage V = Vac−Vz is applied to the device 30. As a result, the device 30 is protected from overvoltage.
　その後、過電圧状態が続いている場合には、商用電源９０の電圧Ｖａｃの上昇に伴って機器３０に印加される電圧Ｖも上昇する。しかし、電圧Ｖａｃが第２閾値に到達したときに第２スイッチ１２が電源ライン９０１を遮断する。この結果、機器３０を保護し、且つインピーダンス回路２０での電力消費を止める。 Thereafter, when the overvoltage state continues, the voltage V applied to the device 30 increases as the voltage Vac of the commercial power supply 90 increases. However, the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches the second threshold value. As a result, the device 30 is protected and power consumption in the impedance circuit 20 is stopped.
　インピーダンスＺがインダクタンス成分を含む場合には、商用電源９０の電圧Ｖａｃが増加して制御部４０がスイッチ１１をオフさせたとき、スイッチ１１のオフ後の電圧Ｖの上昇は、インピーダンスＺが抵抗だけの場合に比べて、緩やかに上昇する。 When the impedance Z includes an inductance component, when the voltage Vac of the commercial power supply 90 increases and the control unit 40 turns off the switch 11, the increase in the voltage V after the switch 11 is turned off is that the impedance Z is only a resistance. Compared to the case, it rises more slowly.
　したがって、第２スイッチ１２で電源ライン９０１を遮断が遅くなっても、そのダメージはインピーダンスＺが抵抗だけの場合に比べて小さい。つまり、インピーダンスＺの電力定格が小さいままでも、機器３０を短時間の過電圧から保護することができる。 Therefore, even when the power supply line 901 is delayed by the second switch 12, the damage is small compared to the case where the impedance Z is only a resistance. That is, the device 30 can be protected from a short-time overvoltage even when the power rating of the impedance Z is small.
　商用電源９０の電圧Ｖａｃが下がり、電圧検出器３３から出力される電圧が復帰のための閾値よりも下がったと制御部４０が判定したとき、制御部４０は、スイッチ１１の発光ダイオード１１ａへ通電し、フォトトライアック１１ｂをオンさせる。さらに、第２スイッチ１２をオンさせて電源ライン９０１を接続することで、通常の動作に復帰する。 When the control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 energizes the light emitting diode 11a of the switch 11. Then, the photo triac 11b is turned on. Further, the second switch 12 is turned on and the power supply line 901 is connected to return to the normal operation.
　（４）第２実施形態の特徴
　（４－１）
　過電圧保護回路５０では、通常時はスイッチ１１をオンにしてバイパス回路３５を閉じているので、インピーダンス回路２０で電力が消費されることはなく、機器３０への印加電圧がインピーダンス回路２０での電圧降下分だけ低くなることも回避することができる。 (4) Features of the second embodiment (4-1)
In the overvoltage protection circuit 50, since the switch 11 is normally turned on and the bypass circuit 35 is closed, no power is consumed in the impedance circuit 20, and the voltage applied to the device 30 is the voltage applied to the impedance circuit 20. It is also possible to avoid lowering by the amount of descent.
　（４－２）
　また、過電圧時には、スイッチ１１がオフすることによって、インピーダンス回路２０のインピーダンスＺの電圧降下分だけ機器３０に印加される電圧が低減され、機器３０を過電圧から保護することができる。 (4-2)
Further, when the voltage is overvoltage, the switch 11 is turned off, so that the voltage applied to the device 30 is reduced by the voltage drop of the impedance Z of the impedance circuit 20, and the device 30 can be protected from the overvoltage.
　（４－３）
　また、第２スイッチ１２が電源ライン９０１を遮断することによってインピーダンス回路２０での電力消費を止める。この結果、インピーダンス回路２０の過熱を抑制し、電力定格を小さくすることができる。 (4-3)
Further, the second switch 12 cuts off the power supply line 901 to stop power consumption in the impedance circuit 20. As a result, overheating of the impedance circuit 20 can be suppressed and the power rating can be reduced.
　（４－４）
　商用電源９０からの供給電圧が過大電圧であっても、インピーダンス回路２０での電圧降下分だけ機器３０に印加される電圧が低減される。それゆえ、短時間の過大電圧からの保護だけのために機器３０の電圧定格を高く設計する必要がなく、合理的である。 (4-4)
Even if the supply voltage from the commercial power supply 90 is an excessive voltage, the voltage applied to the device 30 is reduced by the voltage drop in the impedance circuit 20. Therefore, it is not necessary to design the device 30 with a high voltage rating only for protection from an excessive voltage for a short time, which is reasonable.
　＜第３実施形態＞
　（１）電力変換装置３００の構成
　図７は、本発明の第３実施形態に係る過電圧保護回路１００を備えた電力変換装置３００の回路図である。図７において、電力変換装置３００は、直流電源部８０、インバータ９５、過電圧保護回路１００で構成されている。 <Third Embodiment>
(1) Configuration of Power Converter 300 FIG. 7 is a circuit diagram of a power converter 300 including an overvoltage protection circuit 100 according to the third embodiment of the present invention. In FIG. 7, the power conversion device 300 includes a DC power supply unit 80, an inverter 95, and an overvoltage protection circuit 100.
　インバータ９５は、直流電源部８０から一対の電源ライン８０１，８０２を介して電力供給されている。過電圧保護回路１００は、直流電源部８０とインバータ９５との間に接続されている。 The inverter 95 is supplied with power from the DC power supply unit 80 via a pair of power supply lines 801 and 802. The overvoltage protection circuit 100 is connected between the DC power supply unit 80 and the inverter 95.
　（１－１）直流電源部８０
　直流電源部８０は、整流部８１と、整流部８１と並列接続される平滑コンデンサ８２とで構成されている。 (1-1) DC power supply unit 80
The DC power supply unit 80 includes a rectifying unit 81 and a smoothing capacitor 82 connected in parallel with the rectifying unit 81.
　整流部８１は、４つのダイオードＤ１ａ，Ｄ１ｂ，Ｄ２ａ，Ｄ２ｂによってブリッジ状に構成されている。具体的には、ダイオードＤ１ａとＤ１ｂ、Ｄ２ａとＤ２ｂは、それぞれ互いに直列に接続されている。ダイオードＤ１ａ，Ｄ２ａの各カソード端子は、共に平滑コンデンサ８２のプラス側端子に接続されており、整流部８１の正側出力端子として機能する。ダイオードＤ１ｂ，Ｄ２ｂの各ダイオードの各アノード端子は、共に平滑コンデンサ８２のマイナス側端子に接続されており、整流部８１の負側出力端子として機能する。 The rectifying unit 81 is configured in a bridge shape by four diodes D1a, D1b, D2a, and D2b. Specifically, the diodes D1a and D1b and D2a and D2b are respectively connected in series. The cathode terminals of the diodes D1a and D2a are both connected to the plus side terminal of the smoothing capacitor 82 and function as the positive side output terminal of the rectifying unit 81. The anode terminals of the diodes D1b and D2b are both connected to the minus terminal of the smoothing capacitor 82 and function as the negative output terminal of the rectifier 81.
　ダイオードＤ１ａ及びダイオードＤ１ｂの接続点は、商用電源９０の一方の極に接続されている。ダイオードＤ２ａ及びダイオードＤ２ｂの接続点は、商用電源９０の他方の極に接続されている。整流部８１は、商用電源９０から出力される交流電圧を整流して直流電圧を生成し、これを平滑コンデンサ８２へ供給する。 The connection point of the diode D1a and the diode D1b is connected to one pole of the commercial power supply 90. A connection point between the diode D2a and the diode D2b is connected to the other pole of the commercial power supply 90. The rectifying unit 81 rectifies the AC voltage output from the commercial power supply 90 to generate a DC voltage, and supplies this to the smoothing capacitor 82.
　平滑コンデンサ８２は、整流部８１によって整流された電圧を平滑する。平滑後の電圧Ｖｄｃは、平滑コンデンサ８２の出力側に接続されるインバータ９５へ印加される。 The smoothing capacitor 82 smoothes the voltage rectified by the rectifying unit 81. The smoothed voltage Vdc is applied to the inverter 95 connected to the output side of the smoothing capacitor 82.
　なお、コンデンサの種類としては、電解コンデンサやフィルムコンデンサ、タンタルコンデンサ等が挙げられるが、本実施形態においては、平滑コンデンサ８２として電解コンデンサが採用される。 In addition, as a kind of capacitor | condenser, although an electrolytic capacitor, a film capacitor, a tantalum capacitor etc. are mentioned, an electrolytic capacitor is employ | adopted as the smoothing capacitor 82 in this embodiment.
　この直流電源部８０は、交流電圧を直流電圧に変換するコンバータ回路と言い換えることもできる。 The DC power supply unit 80 can be rephrased as a converter circuit that converts an AC voltage into a DC voltage.
　（１－２）インバータ９５
　インバータ９５は、複数のＩＧＢＴ（絶縁ゲート型バイポーラトランジスタ、以下、単にトランジスタという）及び複数の還流用ダイオードを含んでいる。インバータ９５は、平滑コンデンサ８２からの電圧Ｖｄｃが印加され、かつゲート駆動回路９６により指示されたタイミングで各トランジスタがオン及びオフを行うことによって、モータ５００を駆動する駆動電圧を生成する。モータ５００は、例えばヒートポンプ式空気調和機の圧縮機モータ、ファンモータである。 (1-2) Inverter 95
The inverter 95 includes a plurality of IGBTs (insulated gate bipolar transistors, hereinafter simply referred to as transistors) and a plurality of free-wheeling diodes. The inverter 95 is applied with the voltage Vdc from the smoothing capacitor 82, and each transistor is turned on and off at the timing instructed by the gate drive circuit 96, thereby generating a drive voltage for driving the motor 500. The motor 500 is, for example, a compressor motor or a fan motor of a heat pump type air conditioner.
　なお、本実施形態のインバータ９５は、電圧形インバータであるが、それに限定されるものではなく、電流形インバータでもよい。 In addition, although the inverter 95 of this embodiment is a voltage source inverter, it is not limited to it, A current source inverter may be sufficient.
　（１－３）ゲート駆動回路９６
　ゲート駆動回路９６は、制御部４０からの指令に基づき、インバータ９５の各トランジスタのオン及びオフの状態を変化させる。 (1-3) Gate drive circuit 96
The gate drive circuit 96 changes the on / off state of each transistor of the inverter 95 based on a command from the control unit 40.
　（１－４）過電圧保護回路１００
　過電圧保護回路１００は、インピーダンス回路７０と、電圧検出器８３、バイパス回路８５と、第２スイッチ６２とを含んでいる。 (1-4) Overvoltage protection circuit 100
The overvoltage protection circuit 100 includes an impedance circuit 70, a voltage detector 83, a bypass circuit 85, and a second switch 62.
　（２）過電圧保護回路１００の詳細構成
　第３実施形態と、既に説明した第１実施形態及び第２実施形態と大きく異なる点は、過電圧保護回路１００が直流部に設けられていることである。したがって、各構成要素も交流仕様から直流仕様に置き換えられることに鑑みて、同一名称であっても符号を換えて、再度説明する。 (2) Detailed Configuration of Overvoltage Protection Circuit 100 The third embodiment is different from the first and second embodiments already described in that the overvoltage protection circuit 100 is provided in the direct current section. Therefore, in view of the fact that each component is also replaced from the AC specification to the DC specification, the description will be given again by changing the code even if the names are the same.
　（２－１）インピーダンス回路７０
　インピーダンス回路７０は、当該回路における電圧と電流との比であるインピーダンスがＺとなるように構成された回路である。一般に抵抗素子が採用される。 (2-1) Impedance circuit 70
The impedance circuit 70 is a circuit configured such that an impedance that is a ratio of a voltage and a current in the circuit is Z. In general, a resistance element is employed.
　インピーダンス回路７０は、電源ライン８０２上で、直流電源部８０とインバータ９５との間に接続されている。 The impedance circuit 70 is connected between the DC power supply unit 80 and the inverter 95 on the power supply line 802.
　（２－２）電圧検出器８３
　電圧検出器８３は、平滑コンデンサ８２の出力側に接続されており、平滑コンデンサ８２の両端電圧、即ち平滑後の電圧Ｖｄｃの値を検出する。電圧検出器８３は、例えば、互いに直列に接続された２つの抵抗が平滑コンデンサ８２に並列接続され、電圧Ｖｄｃが分圧されるように構成される。それら２つの抵抗同士の接続点の電圧値は、制御部４０に入力される。 (2-2) Voltage detector 83
The voltage detector 83 is connected to the output side of the smoothing capacitor 82, and detects the voltage across the smoothing capacitor 82, that is, the value of the smoothed voltage Vdc. For example, the voltage detector 83 is configured such that two resistors connected in series with each other are connected in parallel to the smoothing capacitor 82 and the voltage Vdc is divided. The voltage value at the connection point between the two resistors is input to the control unit 40.
　（２－３）バイパス回路８５
　バイパス回路８５は、インピーダンス回路７０に並列接続されており、インピーダンス回路７０を迂回する回路である。バイパス回路８５は、スイッチ６１を有している。スイッチ６１は、バイパス回路８５を開閉する。ここで、バイパス回路８５を開閉するとは、バイパス回路８５を導通又は遮断して非導通にすることである。 (2-3) Bypass circuit 85
The bypass circuit 85 is a circuit that is connected in parallel to the impedance circuit 70 and bypasses the impedance circuit 70. The bypass circuit 85 has a switch 61. The switch 61 opens and closes the bypass circuit 85. Here, opening and closing the bypass circuit 85 means making the bypass circuit 85 conductive or blocked to make it non-conductive.
　（２－４）スイッチ６１
　スイッチ６１は、通常時はバイパス回路８５を閉、つまり導通状態にしておく。なぜなら、通常時にバイパス回路８５を開（非導通状態）にしておくと、インピーダンス回路７０で常に電力消費される上に、インバータ９５への印加電圧がインピーダンス回路７０のインピーダンスＺの電圧降下分だけ低くなるからである。 (2-4) Switch 61
The switch 61 normally closes the bypass circuit 85, that is, keeps it conductive. This is because if the bypass circuit 85 is left open (non-conducting state) during normal operation, power is always consumed by the impedance circuit 70 and the voltage applied to the inverter 95 is lowered by the voltage drop of the impedance Z of the impedance circuit 70. Because it becomes.
　他方、過電圧時はインバータ９５を保護するためにバイパス回路８５を素早く開にして、直流電源部８０―インバータ９５―インピーダンス回路７０―直流電源部８０という閉回路が構成する必要がある。そのため、スイッチ６１には、高速動作が求められる。本実施形態では、トランジスタが採用されているが、スイッチ６１の形態は本実施形態に限定されるものではない。 On the other hand, in order to protect the inverter 95 at the time of overvoltage, it is necessary to quickly open the bypass circuit 85 to form a closed circuit of the DC power supply unit 80-inverter 95-impedance circuit 70-DC power supply unit 80. For this reason, the switch 61 is required to operate at high speed. In this embodiment, a transistor is employed, but the form of the switch 61 is not limited to this embodiment.
　図７に示すように、スイッチ６１は、フォトカプラ６１ａと、駆動回路６１ｂと、トランジスタ６１ｃとで構成されている。フォトカプラ６１ａは、発光ダイオード６１１とフォトトランジスタ６１２を内蔵している。 As shown in FIG. 7, the switch 61 is composed of a photocoupler 61a, a drive circuit 61b, and a transistor 61c. The photocoupler 61a includes a light emitting diode 611 and a phototransistor 612.
　スイッチ６１の入力側（Ｃ１－Ｃ２間）にはフォトカプラ６１ａの発光ダイオード６１１が接続されている。発光ダイオード６１１のアノードＣ１は抵抗Ｒ１を介して電源Ｖｃに接続されている。発光ダイオード６１１のカソードＣ２は信号線を介して制御部４０に接続されている。また、フォトトランジスタ６１２は駆動回路６１ｂとＧＮＤとの間に接続されている。 The light emitting diode 611 of the photocoupler 61a is connected to the input side (between C1 and C2) of the switch 61. The anode C1 of the light emitting diode 611 is connected to the power source Vc via the resistor R1. The cathode C2 of the light emitting diode 611 is connected to the control unit 40 via a signal line. The phototransistor 612 is connected between the drive circuit 61b and GND.
　スイッチ６１の出力側（Ｄ１－Ｄ２間）にトランジスタ６１ｃが設けられている。トランジスタ６１ｃのコレクタＤ１はインピーダンス回路７０とインバータ９５との間に接続されている。また、トランジスタ６１ｃのエミッタＤ２はインピーダンス回路７０と直流電源部８０との間に接続されている。 A transistor 61c is provided on the output side (between D1 and D2) of the switch 61. The collector D1 of the transistor 61c is connected between the impedance circuit 70 and the inverter 95. The emitter D2 of the transistor 61c is connected between the impedance circuit 70 and the DC power supply unit 80.
　制御部４０の制御信号は、フォトカプラ６１ａを介して駆動回路６１ｂに入力される。駆動回路６１ｂには、駆動用電源（図示せず）が接続されており、制御部４０が発光ダイオード６１１の信号ラインをオンさせると、発光ダイオード６１１が発光しフォトトランジスタ６１２が導通する。このフォトトランジスタ６１２が導通している間、駆動回路６１ｂからトランジスタ６１ｃのベースに駆動信号が出力され、トランジスタ６１ｃのコレクタＤ１－エミッタＤ２間が導通する。 The control signal of the control unit 40 is input to the drive circuit 61b via the photocoupler 61a. A driving power supply (not shown) is connected to the driving circuit 61b. When the control unit 40 turns on the signal line of the light emitting diode 611, the light emitting diode 611 emits light and the phototransistor 612 becomes conductive. While the phototransistor 612 is conducting, a driving signal is output from the driving circuit 61b to the base of the transistor 61c, and the collector D1-emitter D2 of the transistor 61c is conducted.
　逆に、制御部４０が発光ダイオード６１１の信号ラインをオフさせると、発光ダイオード６１１が発光しないので、フォトトランジスタ６１２は導通しない。このフォトトランジスタ６１２が導通していない間、トランジスタ６１ｃのコレクタＤ１－エミッタＤ２間も導通しない。 Conversely, when the control unit 40 turns off the signal line of the light emitting diode 611, the light emitting diode 611 does not emit light, and the phototransistor 612 does not conduct. While the phototransistor 612 is not conducting, the collector D1 and the emitter D2 of the transistor 61c are not conducted.
　（２－５）第２スイッチ６２
　第２スイッチ６２は、電源ライン８０１を開閉する。ここで、電源ライン８０１を開閉するとは、電源ライン８０１を導通又は遮断して非導通にすることである。 (2-5) Second switch 62
The second switch 62 opens and closes the power line 801. Here, opening and closing the power supply line 801 is to turn the power supply line 801 on or off to make it non-conductive.
　第２スイッチ６２は、通常時は電源ライン８０１を閉、つまり導通状態にしておく。他方、過電圧時には、スイッチ６１がオフして、直流電源部８０―インバータ９５―インピーダンス回路７０―直流電源部８０という閉回路が構成され、インバータ９５の保護動作が行われた後に、第２スイッチ６２がオフして電源ライン８０１を遮断する。 The second switch 62 normally closes the power supply line 801, that is, keeps it conductive. On the other hand, when overvoltage occurs, the switch 61 is turned off to form a closed circuit of the DC power supply unit 80-inverter 95-impedance circuit 70-DC power supply unit 80. After the protective operation of the inverter 95 is performed, the second switch 62 Is turned off and the power line 801 is shut off.
　電源ライン８０１を遮断する目的は、インピーダンス回路７０での電力消費を止めるためであり、インピーダンス回路７０の電力定格を小さくすることができ、低コスト化を図ることができる。 The purpose of cutting off the power supply line 801 is to stop the power consumption in the impedance circuit 70, the power rating of the impedance circuit 70 can be reduced, and the cost can be reduced.
　第２スイッチ６２は、スイッチ６１のような高速性は求められないので、本実施形態ではリレー回路が採用されている。 Since the second switch 62 is not required to be as fast as the switch 61, a relay circuit is employed in this embodiment.
　図７に示すように、第２スイッチ６２は、電源ライン８０１を開閉するリレー接点６２ａと、リレー接点６２ａを動作させるリレーコイル６２ｂと、リレーコイル６２ｂへの通電と非通電とを行うトランジスタ６２ｃとを含んでいる。リレーコイル６２ｂの一端は、電源Ｖｂの正極に接続され、他端はトランジスタ６２ｃのコレクタ側に接続されている。制御部４０は、トランジスタ６２ｃのベース電流の有無を切り換えて、コレクタとエミッタ間をオンオフし、リレーコイル６２ｂへの通電と非通電を行う。 As shown in FIG. 7, the second switch 62 includes a relay contact 62a for opening and closing the power supply line 801, a relay coil 62b for operating the relay contact 62a, and a transistor 62c for energizing and de-energizing the relay coil 62b. Is included. One end of the relay coil 62b is connected to the positive electrode of the power supply Vb, and the other end is connected to the collector side of the transistor 62c. The controller 40 switches between the presence and absence of the base current of the transistor 62c, turns on and off the collector and the emitter, and performs energization and de-energization of the relay coil 62b.
　（３）過電圧保護回路１００の動作
　図７において、通常時、バイパス回路８５はスイッチ６１が閉じて導通状態であり、且つ第２スイッチ６２は電源ライン８０１を導通状態にしているので、インバータ９５には電圧Ｖ＝Ｖｄｃが印加されている。 (3) Operation of Overvoltage Protection Circuit 100 In FIG. 7, normally, the bypass circuit 85 is in the conductive state with the switch 61 closed, and the second switch 62 has the power supply line 801 in the conductive state. The voltage V = Vdc is applied.
　直流電源部８０の電圧Ｖｄｃが急激に増加し、制御部４０が電圧検出器８３から出力される電圧が閾値を超えたと判定したとき、制御部４０はスイッチ６１の発光ダイオード６１１への通電を停止し、フォトトランジスタ６１２をオフさせる。 When the voltage Vdc of the DC power supply unit 80 increases rapidly and the control unit 40 determines that the voltage output from the voltage detector 83 exceeds the threshold value, the control unit 40 stops energizing the light emitting diode 611 of the switch 61. Then, the phototransistor 612 is turned off.
　その結果、直流電源部８０―インバータ９５―インピーダンス回路７０―直流電源部８０という閉回路が構成される。このとき、インバータ９５には電圧Ｖ＝Ｖｄｃ－Ｖｚしか印加されない。その結果、インバータ９５が過電圧から保護される。 As a result, a closed circuit including the DC power supply unit 80, the inverter 95, the impedance circuit 70, and the DC power supply unit 80 is formed. At this time, only the voltage V = Vdc−Vz is applied to the inverter 95. As a result, the inverter 95 is protected from overvoltage.
　その後、過電圧状態が続いている場合には、第２スイッチ６２が電源ライン８０１を遮断して、インピーダンス回路７０での電力消費を止める。 Thereafter, when the overvoltage state continues, the second switch 62 cuts off the power supply line 801 and stops the power consumption in the impedance circuit 70.
　商用電源９０の電圧Ｖａｃが下がり、電圧検出器８３から出力される電圧が復帰のための閾値よりも下がったと制御部４０が判定したとき、制御部４０はスイッチ６１の発光ダイオード６１１へ通電し、トランジスタ６１ｃをオンさせる。さらに、第２スイッチ６２をオンさせて電源ライン８０１を接続することで、通常の動作に復帰する。 When the control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 83 has fallen below the threshold for recovery, the control unit 40 energizes the light emitting diode 611 of the switch 61, The transistor 61c is turned on. Further, by turning on the second switch 62 and connecting the power supply line 801, the normal operation is restored.
　（４）第３実施形態の特徴
　（４－１）
　過電圧保護回路１００では、通常時はスイッチ６１をオンにしてバイパス回路８５を閉じているので、インピーダンス回路７０で電力が消費されることはなく、インバータ９５への印加電圧がインピーダンス回路７０での電圧降下分だけ低くなることも回避することができる。 (4) Features of the third embodiment (4-1)
In the overvoltage protection circuit 100, the switch 61 is normally turned on and the bypass circuit 85 is closed, so that no power is consumed in the impedance circuit 70, and the voltage applied to the inverter 95 is the voltage at the impedance circuit 70. It is also possible to avoid lowering by the amount of descent.
　（４－２）
　また、過電圧時には、スイッチ６１がオフすることによって、インピーダンス回路７０のインピーダンスＺの電圧降下分だけインバータ９５に印加される電圧が低減され、インバータ９５を過電圧から保護することができる。 (4-2)
Further, when the overvoltage is applied, the switch 61 is turned off, whereby the voltage applied to the inverter 95 is reduced by the voltage drop of the impedance Z of the impedance circuit 70, and the inverter 95 can be protected from the overvoltage.
　（４－３）
　また、第２スイッチ６２が電源ライン８０１を遮断することによってインピーダンス回路７０での電力消費を止める。この結果、インピーダンス回路７０の電力定格を小さくすることができる。 (4-3)
Further, the second switch 62 cuts off the power supply line 801 to stop the power consumption in the impedance circuit 70. As a result, the power rating of the impedance circuit 70 can be reduced.
　（４－４）
　さらに、直流電源部８０の下流側に配置されるスイッチ６１は片方向スイッチでよいので、スイッチの低コスト化を図ることができる。 (4-4)
Furthermore, since the switch 61 arranged on the downstream side of the DC power supply unit 80 may be a one-way switch, the cost of the switch can be reduced.
　＜第４実施形態＞
　（１）過電圧保護回路１００の構成
　図８は、本発明の第４実施形態に係る過電圧保護回路１００を備えた電力変換装置３００の回路図である。図８において、インバータ９５は、直流電源部８０から一対の電源ライン８０１，８０２を介して電力供給されている。過電圧保護回路１００の一部は商用電源９０と直流電源部８０との間に接続され、他の部分は直流電源部８０とインバータ９５との間に接続されている。 <Fourth embodiment>
(1) Configuration of Overvoltage Protection Circuit 100 FIG. 8 is a circuit diagram of a power conversion device 300 including the overvoltage protection circuit 100 according to the fourth embodiment of the present invention. In FIG. 8, the inverter 95 is supplied with power from a DC power supply unit 80 via a pair of power supply lines 801 and 802. A part of the overvoltage protection circuit 100 is connected between the commercial power supply 90 and the DC power supply unit 80, and the other part is connected between the DC power supply unit 80 and the inverter 95.
　過電圧保護回路１００は、インピーダンス回路７０と、電圧検出器３３、バイパス回路８５と、第２スイッチ１２とを含んでいる。 The overvoltage protection circuit 100 includes an impedance circuit 70, a voltage detector 33, a bypass circuit 85, and the second switch 12.
　第４実施形態と、既に説明した第３実施形態と異なる点は、過電圧保護回路１００の構成要素である電圧検出器と第２スイッチとが商用電源９０と直流電源部８０との間に設けられていることである。つまり、電圧検出器及び第２スイッチの配置が、第２実施形態における電圧検出器３３及び第２スイッチ１２の配置と同じである。したがって、電圧検出器及び第２スイッチが直流仕様から交流仕様に置き換えられることに鑑みて、第２実施形態の電圧検出器３３及び第２スイッチ１２が採用されている。 The difference between the fourth embodiment and the already described third embodiment is that a voltage detector and a second switch, which are components of the overvoltage protection circuit 100, are provided between the commercial power supply 90 and the DC power supply unit 80. It is that. That is, the arrangement of the voltage detector and the second switch is the same as the arrangement of the voltage detector 33 and the second switch 12 in the second embodiment. Therefore, in view of the fact that the voltage detector and the second switch are replaced from the DC specification to the AC specification, the voltage detector 33 and the second switch 12 of the second embodiment are employed.
　したがって、各構成要素の内容は、第２実施形態の電圧検出器３３及び第２スイッチ１２、第３実施形態のインピーダンス回路７０、及びバイパス回路８５と同様であるので、ここでは説明を省略し、動作説明のみ行う。 Therefore, the content of each component is the same as that of the voltage detector 33 and the second switch 12 of the second embodiment, the impedance circuit 70 of the third embodiment, and the bypass circuit 85. Only the operation is explained.
　（２）過電圧保護回路１００の動作
　図８において、通常時、バイパス回路８５はスイッチ６１が閉じて導通状態であり、且つ第２スイッチ１２は電源ライン９０１を導通状態にしているので、インバータ９５には電圧Ｖ＝Ｖｄｃが印加されている。 (2) Operation of Overvoltage Protection Circuit 100 In FIG. 8, normally, the bypass circuit 85 is in the conductive state with the switch 61 closed, and the second switch 12 has the power supply line 901 in the conductive state. The voltage V = Vdc is applied.
　商用電源９０の電圧Ｖａｃの変動により、直流電源部８０の電圧Ｖｄｃが急激に変動し過電圧となったとき、制御部４０は電圧検出器３３から出力される電圧が閾値を超えたと判定し、スイッチ６１の発光ダイオード６１１への通電を停止し、トランジスタ６１ｃをオフさせる。 When the voltage Vdc of the DC power supply unit 80 suddenly fluctuates and becomes an overvoltage due to the fluctuation of the voltage Vac of the commercial power supply 90, the control unit 40 determines that the voltage output from the voltage detector 33 exceeds the threshold, and the switch The current supply to the light emitting diode 611 of 61 is stopped, and the transistor 61c is turned off.
　その結果、直流電源部８０―インバータ９５―インピーダンス回路７０―直流電源部８０という閉回路が構成される。このとき、インバータ９５には電圧Ｖ＝Ｖｄｃ－Ｖｚしか印加されない。その結果、インバータ９５が過電圧から保護される。 As a result, a closed circuit including the DC power supply unit 80, the inverter 95, the impedance circuit 70, and the DC power supply unit 80 is formed. At this time, only the voltage V = Vdc−Vz is applied to the inverter 95. As a result, the inverter 95 is protected from overvoltage.
　その後、第２スイッチ１２が電源ライン９０１を遮断して、インピーダンス回路７０での電力消費を止める。 Thereafter, the second switch 12 cuts off the power supply line 901 and stops the power consumption in the impedance circuit 70.
　（３）第４実施形態の特徴
　（３－１）
　過電圧保護回路１００では、通常時はスイッチ６１をオンにしてバイパス回路８５を閉じているので、インピーダンス回路７０で電力が消費されることはなく、インバータ９５への印加電圧がインピーダンス回路７０での電圧降下分だけ低くなることも回避することができる。 (3) Features of the fourth embodiment (3-1)
In the overvoltage protection circuit 100, the switch 61 is normally turned on and the bypass circuit 85 is closed, so that no power is consumed in the impedance circuit 70, and the voltage applied to the inverter 95 is the voltage at the impedance circuit 70. It is also possible to avoid lowering by the amount of descent.
　（３－２）
　また、過電圧時には、スイッチ６１がオフすることによって、インピーダンス回路７０のインピーダンスＺの電圧降下分だけインバータ９５に印加される電圧が低減され、インバータ９５を過電圧から保護することができる。 (3-2)
Further, when the overvoltage is applied, the switch 61 is turned off, whereby the voltage applied to the inverter 95 is reduced by the voltage drop of the impedance Z of the impedance circuit 70, and the inverter 95 can be protected from the overvoltage.
　（３－３）
　また、第２スイッチ１２が電源ライン９０１を遮断することによってインピーダンス回路７０での電力消費を止める。この結果、インピーダンス回路７０の過熱を抑制し、電力定格を小さくすることができる。 (3-3)
Further, the second switch 12 cuts off the power supply line 901 to stop the power consumption in the impedance circuit 70. As a result, overheating of the impedance circuit 70 can be suppressed and the power rating can be reduced.
　（３－４）
　さらに、直流電源部８０の下流側に配置されるスイッチ６１は片方向スイッチでよいので、スイッチの低コスト化を図ることができる。 (3-4)
Furthermore, since the switch 61 arranged on the downstream side of the DC power supply unit 80 may be a one-way switch, the cost of the switch can be reduced.
　＜変形例＞
　（Ａ）
　図１に示す第１実施形態に係る過電圧保護回路５０は、交流電圧に対する過電圧保護回路を実施形態としているが、電源が直流電源である場合、あるいは機器内に交流電源を整流する直流電源部を持つ場合には、各構成要素を交流仕様から直流仕様へ置き換えて直流電源部の下流側に設けてもよい。 <Modification>
(A)
The overvoltage protection circuit 50 according to the first embodiment shown in FIG. 1 is an overvoltage protection circuit for an AC voltage, but when the power supply is a DC power supply, or a DC power supply unit that rectifies the AC power supply in the device. In the case of having it, each component may be replaced from the AC specification to the DC specification and provided on the downstream side of the DC power supply unit.
　（Ｂ）
　第２実施形態では、電圧Ｖａｃが所定の第２閾値に達したときに第２スイッチ１２が電源ライン９０１を遮断したが、過電圧状態が所定の継続時間を経過したときに遮断するようにしてもよい。 (B)
In the second embodiment, the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches a predetermined second threshold, but it may be cut off when the overvoltage state has passed a predetermined duration. Good.
　図９は、インピーダンスＺが抵抗のみの場合の電圧Ｖの変化を示すグラフである。図５及び図９において、通常時、バイパス回路３５はスイッチ１１が閉じて導通状態であり、且つ第２スイッチ１２は電源ライン９０１を導通状態にしているので、機器３０には電圧Ｖ＝Ｖａｃが印加されている。 FIG. 9 is a graph showing a change in the voltage V when the impedance Z is only a resistance. 5 and 9, normally, the bypass circuit 35 is in the conductive state with the switch 11 closed, and the second switch 12 has the power supply line 901 in the conductive state, so that the voltage V = Vac is applied to the device 30. Applied.
　商用電源９０の電圧Ｖａｃが急激に増加し、制御部４０が電圧検出器３３から出力される電圧が閾値を超えたと判定したとき、制御部４０はスイッチ１１の発光ダイオード１１ａへの通電を停止し、フォトトライアック１１ｂをオフさせる。 When the voltage Vac of the commercial power supply 90 suddenly increases and the control unit 40 determines that the voltage output from the voltage detector 33 has exceeded the threshold, the control unit 40 stops energizing the light emitting diode 11a of the switch 11. Then, the photo triac 11b is turned off.
　その結果、商用電源９０―機器３０―インピーダンス回路２０―商用電源９０という閉回路が構成される。このとき、機器３０には電圧Ｖ＝Ｖａｃ－Ｖｚしか印加されない。その結果、機器３０が過電圧から保護される。 As a result, a closed circuit of the commercial power source 90 -the device 30 -the impedance circuit 20 -the commercial power source 90 is configured. At this time, only the voltage V = Vac−Vz is applied to the device 30. As a result, the device 30 is protected from overvoltage.
　その後、過電圧状態が続いている場合には、商用電源９０の電圧Ｖａｃの上昇に伴って機器３０に印加される電圧Ｖも上昇するが、電圧Ｖａｃが閾値を越えてから過電圧状態が所定の継続時間判定値に到達したときに第２スイッチ１２が電源ライン９０１を遮断する。この結果、機器３０を保護し、且つインピーダンス回路２０での電力消費を止める。 Thereafter, when the overvoltage state continues, the voltage V applied to the device 30 increases as the voltage Vac of the commercial power supply 90 increases, but the overvoltage state continues for a predetermined duration after the voltage Vac exceeds the threshold value. When the time determination value is reached, the second switch 12 cuts off the power supply line 901. As a result, the device 30 is protected and power consumption in the impedance circuit 20 is stopped.
　（Ｃ）
　第２実施形態では、電圧Ｖａｃが所定の第２閾値に達したときに第２スイッチ１２が電源ライン９０１を遮断したが、機器に印加される電圧Ｖを検出する機器電圧検出器３７を更に設け、電圧Ｖが所定の第３閾値に達したときに遮断するようにしてもよい（このときの回路図を図１１に示す）。 (C)
In the second embodiment, the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches a predetermined second threshold. However, a device voltage detector 37 for detecting the voltage V applied to the device is further provided. The voltage V may be cut off when it reaches a predetermined third threshold (a circuit diagram at this time is shown in FIG. 11).
　図１０は、インピーダンスＺが抵抗のみの場合の電圧Ｖの変化を示すグラフである。図５及び図１０において、通常時、バイパス回路３５はスイッチ１１が閉じて導通状態であり、且つ第２スイッチ１２は電源ライン９０１を導通状態にしているので、機器３０には電圧Ｖ＝Ｖａｃが印加されている。 FIG. 10 is a graph showing changes in voltage V when impedance Z is only resistance. 5 and 10, normally, the bypass circuit 35 is in a conductive state with the switch 11 closed, and the second switch 12 has a power supply line 901 in a conductive state, so that the voltage V = Vac is applied to the device 30. Applied.
　商用電源９０の電圧Ｖａｃが急激に増加し、制御部４０が電圧検出器３３から出力される電圧が閾値を超えたと判定したとき、制御部４０はスイッチ１１の発光ダイオード１１ａへの通電を停止し、フォトトライアック１１ｂをオフさせる。 When the voltage Vac of the commercial power supply 90 suddenly increases and the control unit 40 determines that the voltage output from the voltage detector 33 has exceeded the threshold, the control unit 40 stops energizing the light emitting diode 11a of the switch 11. Then, the photo triac 11b is turned off.
　その結果、商用電源９０―機器３０―インピーダンス回路２０―商用電源９０という閉回路が構成される。このとき、機器３０には電圧Ｖ＝Ｖａｃ－Ｖｚしか印加されない。その結果、機器３０が過電圧から保護される。 As a result, a closed circuit of the commercial power source 90 -the device 30 -the impedance circuit 20 -the commercial power source 90 is configured. At this time, only the voltage V = Vac−Vz is applied to the device 30. As a result, the device 30 is protected from overvoltage.
　その後、過電圧状態が続いている場合には、商用電源９０の電圧Ｖａｃの上昇に伴って機器３０に印加される電圧Ｖも上昇するが、電圧Ｖが第３閾値に到達したときに第２スイッチ１２が電源ライン９０１を遮断する。この結果、機器３０を保護し、且つインピーダンス回路２０での電力消費を止める。 Thereafter, when the overvoltage state continues, the voltage V applied to the device 30 increases as the voltage Vac of the commercial power supply 90 increases, but when the voltage V reaches the third threshold value, the second switch 12 cuts off the power line 901. As a result, the device 30 is protected and power consumption in the impedance circuit 20 is stopped.
　（Ｄ）
　第４実施形態は、第３実施形態から、電圧検出器と第２スイッチとを、商用電源９０と直流電源部８０との間に設けるように変更したものであるが、電圧検出器のみを商用電源９０と直流電源部８０との間に設けるようにしてもよい。 (D)
The fourth embodiment is different from the third embodiment in that the voltage detector and the second switch are provided between the commercial power supply 90 and the DC power supply unit 80, but only the voltage detector is commercialized. You may make it provide between the power supply 90 and the DC power supply part 80. FIG.
　（Ｅ）
　第３実施形態、第４実施形態では、機器の内部に過電圧保護回路を持つ例を示したが、機器はコンバータ回路とインバータ回路を持つものに限定されない。 (E)
In 3rd Embodiment and 4th Embodiment, although the example which has an overvoltage protection circuit inside an apparatus was shown, an apparatus is not limited to what has a converter circuit and an inverter circuit.
　＜第５実施形態＞
　（１）過電圧保護回路１５０の構成
　図１２は、本発明の第５実施形態に係る過電圧保護回路１５０を備えた装置の回路図である。図１２において、機器３０は、商用電源９０から一対の電源ライン９０１，９０２を介して電力供給されている。過電圧保護回路１５０は、商用電源９０と機器３０との間に接続されている。 <Fifth Embodiment>
(1) Configuration of Overvoltage Protection Circuit 150 FIG. 12 is a circuit diagram of a device including an overvoltage protection circuit 150 according to the fifth embodiment of the present invention. In FIG. 12, the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902. The overvoltage protection circuit 150 is connected between the commercial power supply 90 and the device 30.
　過電圧保護回路１５０は、可変インピーダンス回路１２０と、電圧検出器３３とを含んでいる。 The overvoltage protection circuit 150 includes a variable impedance circuit 120 and a voltage detector 33.
　（２）過電圧保護回路１５０の詳細構成
　（２－１）可変インピーダンス回路１２０
　可変インピーダンス回路１２０は、当該回路における電圧と電流との比であるインピーダンスがＺとなるように構成された回路である。また、インピーダンスＺは可変である。 (2) Detailed configuration of overvoltage protection circuit 150 (2-1) Variable impedance circuit 120
The variable impedance circuit 120 is a circuit configured such that an impedance that is a ratio of a voltage and a current in the circuit is Z. The impedance Z is variable.
　可変インピーダンス回路１２０は、電源ライン９０２上で、商用電源９０と機器３０との間に接続されている。 The variable impedance circuit 120 is connected between the commercial power supply 90 and the device 30 on the power supply line 902.
　（２－２）電圧検出器３３
　電圧検出器３３は、交流電圧検出回路によって構成されている。交流電圧検出回路は、多様であり、使用条件によって適宜採用される。具体的には、例えば第１実施形態及び第２実施形態で採用されている電圧検出器（図２参照）と同じであるので、ここでは説明を省略する。 (2-2) Voltage detector 33
The voltage detector 33 is configured by an AC voltage detection circuit. There are various AC voltage detection circuits, and they are appropriately adopted depending on use conditions. Specifically, for example, the voltage detector (see FIG. 2) employed in the first embodiment and the second embodiment is the same as the voltage detector, and the description thereof is omitted here.
　（３）過電圧保護回路１５０の動作
　図１３は、機器３０のインピーダンスが抵抗成分のみであり、インピーダンスＺが可変抵抗のみで且つインピーダンスＺが連続的に増加する場合の電圧Ｖの変化を示すグラフである。図１２及び図１３において、通常時、インピーダンスＺは０若しくは０に近い値であるので、機器３０には電圧Ｖ≒Ｖａｃが印加されている。 (3) Operation of Overvoltage Protection Circuit 150 FIG. 13 is a graph showing changes in the voltage V when the impedance of the device 30 is only the resistance component, the impedance Z is only the variable resistance, and the impedance Z continuously increases. is there. 12 and 13, since the impedance Z is 0 or a value close to 0 at normal time, the voltage V≈Vac is applied to the device 30.
　通常時の商用電源９０の電圧Ｖａｃ＝Ｖ0以下であるとすると、商用電源９０の電圧Ｖａｃが増加し、制御部４０が電圧検出器３３から出力される電圧がＶ0を超えたと判定したとき、制御部４０はインピーダンスＺを電圧検出器３３の検出値の増加に応じて連続的に増加させる。 When the voltage Vac of the commercial power supply 90 at normal time is equal to or lower than V 0 , the voltage Vac of the commercial power supply 90 increases and the control unit 40 determines that the voltage output from the voltage detector 33 exceeds V 0. The control unit 40 continuously increases the impedance Z in accordance with the increase in the detection value of the voltage detector 33.
　その結果、可変インピーダンス回路１２０の両端における電圧降下分Ｖｚを減じた電圧Ｖ＝Ｖａｃ－Ｖｚが機器３０に印加されることになり、機器３０は過電圧から保護される。 As a result, the voltage V = Vac−Vz obtained by subtracting the voltage drop Vz at both ends of the variable impedance circuit 120 is applied to the device 30, and the device 30 is protected from overvoltage.
　商用電源９０の電圧Ｖａｃが下がり、電圧検出器３３から出力される電圧が復帰のための閾値よりも下がったと制御部４０が判定したとき、制御部４０は可変インピーダンス回路１２０のインピーダンスＺを０若しくは０に近い値に戻す。これにより、通常の動作に復帰する。 When the control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 sets the impedance Z of the variable impedance circuit 120 to 0 or Return to a value close to zero. As a result, the normal operation is restored.
　（４）変形例
　なお、インピーダンスＺの変化は、必ずしも図１３に示すように連続的な増加である必要はなく、断続的な増加であってもよい。 (4) Modification Note that the change in the impedance Z is not necessarily a continuous increase as shown in FIG. 13, and may be an intermittent increase.
　例えば、図１４は、機器３０のインピーダンスが抵抗成分のみであり、インピーダンスＺが可変抵抗のみで且つインピーダンスＺが段階的に増加する場合の電圧Ｖの変化を示すグラフである。 For example, FIG. 14 is a graph showing a change in the voltage V when the impedance of the device 30 is only the resistance component, the impedance Z is only the variable resistance, and the impedance Z increases stepwise.
　図１２及び図１４において、制御部４０は、商用電源９０の電圧Ｖａｃが通常時の値Ｖ0を超えてもインピーダンスＺは０若しくは０に近い値に維持する。その後、電圧Ｖａｃがさらに上昇し、電圧検出器３３の検出値がＶ1を超えたとき、制御部４０はインピーダンスＺをＺaへ増大させる。その結果、可変インピーダンス回路１２０の両端における電圧降下分Ｖｚが増加し、電圧Ｖ＝Ｖａｃ－Ｖｚが機器３０に印加されることになり、機器３０に印加される電圧ＶがＶ1からＶ0へ減少し、機器３０は過電圧から保護される。 12 and 14, the control unit 40 maintains the impedance Z at 0 or a value close to 0 even when the voltage Vac of the commercial power supply 90 exceeds the normal value V 0 . Thereafter, further increases the voltage Vac, when the detection value of the voltage detector 33 exceeds V 1, the control unit 40 increases the impedance Z to Z a. As a result, an increase in the voltage drop Vz at both ends of the variable impedance circuit 120, will be a voltage V = Vac-Vz is applied to the device 30, the voltage V applied to the device 30 from V 1 to V 0 The device 30 is protected from overvoltage.
　その後も時間の経過に伴って電圧Ｖａｃが上昇するが、制御部４０はインピーダンスＺをＺaに維持する。その後、電圧Ｖａｃがさらに上昇し、電圧検出器３３の検出値がＶ2を超えたとき、制御部４０はインピーダンスＺをＺbへ増大させる。その結果、可変インピーダンス回路１２０の両端における電圧降下分Ｖｚがさらに増加し、電圧Ｖ＝Ｖａｃ－Ｖｚが機器３０に印加されることになり、機器３０に印加される電圧ＶがＶ1からＶ0へ減少し、機器３０は過電圧から保護される。 Thereafter the voltage Vac increases with the passage of time, the control unit 40 maintains the impedance Z to Z a. Thereafter, further increases the voltage Vac, when the detection value of the voltage detector 33 exceeds V 2, the control unit 40 increases the impedance Z to Z b. As a result, the voltage drop Vz at both ends of the variable impedance circuit 120 further increases, and the voltage V = Vac−Vz is applied to the device 30. The voltage V applied to the device 30 is changed from V 1 to V 0. The device 30 is protected from overvoltage.
　（５）第５実施形態の特徴
　（５－１）
　過電圧保護回路１５０では、通常時はインピーダンスＺが小さい値（０を含む）に設定されるので、可変インピーダンス回路１２０での電力消費が抑制され、可変インピーダンス回路１２０での電圧降下も小さく、機器３０への印加電圧が可変インピーダンス回路１２０での電圧降下分だけ低くなることも抑制することができる。 (5) Features of the fifth embodiment (5-1)
In the overvoltage protection circuit 150, since the impedance Z is normally set to a small value (including 0), the power consumption in the variable impedance circuit 120 is suppressed, the voltage drop in the variable impedance circuit 120 is small, and the device 30 It can also be suppressed that the voltage applied to the voltage decreases by the voltage drop in the variable impedance circuit 120.
　他方、過電圧時には、インピーダンスＺが大きい値に設定されるので、可変インピーダンス回路１２０での電圧降下Ｖｚ分だけ機器３０に印加される電圧が低減され、機器３０を過電圧から保護することができる。 On the other hand, since the impedance Z is set to a large value at the time of overvoltage, the voltage applied to the device 30 is reduced by the voltage drop Vz in the variable impedance circuit 120, and the device 30 can be protected from the overvoltage.
　（５－２）
　また、可変インピーダンス回路１２０は、インピーダンスＺを電圧検出器３３による検出値の変化に応じて連続的に変化させることができる。 (5-2)
Further, the variable impedance circuit 120 can continuously change the impedance Z according to the change in the detection value by the voltage detector 33.
　（５－３）
　さらに、可変インピーダンス回路１２０は、インピーダンスＺを電圧検出器３３による検出値の変化に応じて段階的に変化させることもできる。 (5-3)
Furthermore, the variable impedance circuit 120 can change the impedance Z in a stepwise manner in accordance with the change in the detection value by the voltage detector 33.
　＜第６実施形態＞
　（１）過電圧保護回路１５０の構成
　図１５は、本発明の第６実施形態に係る過電圧保護回路１５０を備えた装置の回路図である。図１５において、機器３０は、商用電源９０から一対の電源ライン９０１，９０２を介して電力供給されている。過電圧保護回路１５０は、商用電源９０と機器３０との間に接続されている。 <Sixth Embodiment>
(1) Configuration of Overvoltage Protection Circuit 150 FIG. 15 is a circuit diagram of a device including an overvoltage protection circuit 150 according to the sixth embodiment of the present invention. In FIG. 15, the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902. The overvoltage protection circuit 150 is connected between the commercial power supply 90 and the device 30.
　過電圧保護回路１５０は、可変インピーダンス回路１２０と、電圧検出器３３とを含んでいる。 The overvoltage protection circuit 150 includes a variable impedance circuit 120 and a voltage detector 33.
　（２）過電圧保護回路１５０の詳細構成
　第６実施形態は、可変インピーダンス回路１２０が複数のインピーダンス要素によって構成されている点で上記第５実施形態と相違するが、その他の構成は第５実施形態と同じである。したがって、ここでは可変インピーダンス回路１２０についてのみ説明する。 (2) Detailed Configuration of Overvoltage Protection Circuit 150 The sixth embodiment is different from the fifth embodiment in that the variable impedance circuit 120 is configured by a plurality of impedance elements, but other configurations are the fifth embodiment. Is the same. Therefore, only the variable impedance circuit 120 will be described here.
　（２－１）可変インピーダンス回路１２０
　可変インピーダンス回路１２０は、低インピーダンス要素１２１、高インピーダンス要素１２２及び切換スイッチ１２３を含んでいる。 (2-1) Variable impedance circuit 120
The variable impedance circuit 120 includes a low impedance element 121, a high impedance element 122, and a changeover switch 123.
　可変インピーダンス回路１２０は、切換スイッチ１２３によって低インピーダンス要素１２１と高インピーダンス要素１２２とを選択的に使用することができる。低インピーダンス要素１２１はインピーダンスＺ1を有している。また、高インピーダンス要素１２２はインピーダンスＺ1よりも大きいインピーダンスＺ2を有している。 The variable impedance circuit 120 can selectively use the low impedance element 121 and the high impedance element 122 by the changeover switch 123. The low impedance element 121 has an impedance Z 1 . The high impedance element 122 has an impedance Z 2 that is greater than the impedance Z 1 .
　可変インピーダンス回路１２０は、低インピーダンス要素１２１の使用時に電圧検出器３３の検出値が所定の閾値を超えたとき、使用するインピーダンス要素を低インピーダンス要素１２１から高インピーダンス要素１２２へ切り換えることができる。 The variable impedance circuit 120 can switch the impedance element to be used from the low impedance element 121 to the high impedance element 122 when the detection value of the voltage detector 33 exceeds a predetermined threshold when the low impedance element 121 is used.
　（３）過電圧保護回路１５０の動作
　図１６は、機器３０のインピーダンスが抵抗成分のみであり、インピーダンスＺが抵抗のみの場合の電圧Ｖの変化を示すグラフである。図１５及び図１６において、通常時、可変インピーダンス回路１２０は、切換スイッチ１２３の接点が低インピーダンス要素１２１に接続されている。低インピーダンス要素１２１のインピーダンスＺ1は０若しくは０に近い値であるので、機器３０には電圧Ｖ≒Ｖａｃが印加されている。 (3) Operation of Overvoltage Protection Circuit 150 FIG. 16 is a graph showing changes in the voltage V when the impedance of the device 30 is only the resistance component and the impedance Z is only the resistance. 15 and 16, the variable impedance circuit 120 is normally connected to the low impedance element 121 at the contact point of the changeover switch 123 in the variable impedance circuit 120. Since the impedance Z 1 of the low impedance element 121 is 0 or a value close to 0, the voltage V≈Vac is applied to the device 30.
　通常時の商用電源９０の電圧Ｖａｃ＝Ｖ0とする。制御部４０は、商用電源９０の電圧Ｖａｃが通常時の値Ｖ0を超えても可変インピーダンス回路１２０の低インピーダンス要素１２１の使用し、インピーダンスＺ1を維持する。 It is assumed that the voltage Vac = V 0 of the commercial power supply 90 at normal time. The controller 40 uses the low impedance element 121 of the variable impedance circuit 120 to maintain the impedance Z 1 even when the voltage Vac of the commercial power supply 90 exceeds the normal value V 0 .
　その後、電圧Ｖａｃがさらに上昇し、電圧検出器３３の検出値が第１閾値Ｖ1を超えたとき、制御部４０は切換スイッチ１２３を動作させ、接点を高インピーダンス要素１２２に接続する。 Thereafter, when the voltage Vac further rises and the detection value of the voltage detector 33 exceeds the first threshold value V 1 , the control unit 40 operates the changeover switch 123 to connect the contact point to the high impedance element 122.
　高インピーダンス要素１２２のインピーダンスＺ2は低インピーダンス要素１２１のインピーダンスＺ1より大きいので、可変インピーダンス回路１２０の両端における電圧降下分Ｖｚが増加し、電圧Ｖ＝Ｖａｃ－Ｖｚが機器３０に印加されることになる。 The impedance Z 2 of the high impedance element 122 is greater than the impedance Z 1 of the low impedance element 121, a voltage drop Vz at both ends of the variable impedance circuit 120 is increased, the voltage V = Vac-Vz is applied to the device 30 become.
　その結果、機器３０に印加される電圧ＶがＶ1からＶ0へ減少し、機器３０は過電圧から保護される。 As a result, the voltage V applied to the device 30 decreases from V 1 to V 0 , and the device 30 is protected from overvoltage.
　商用電源９０の電圧Ｖａｃが下がり、電圧検出器３３から出力される電圧が復帰のための閾値よりも下がったと制御部４０が判定したとき、制御部４０は可変インピーダンス回路１２０のインピーダンス要素を高インピーダンス要素１２２から低インピーダンス要素１２１へ切り換えて、インピーダンスＺ2をインピーダンスＺ1に戻す。これにより、通常の動作に復帰する。 When the control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 sets the impedance element of the variable impedance circuit 120 to a high impedance Switching from element 122 to low impedance element 121 returns impedance Z 2 to impedance Z 1 . As a result, the normal operation is restored.
　（４）第６実施形態の特徴
　（４－１）
　過電圧保護回路１５０では、過電圧時には、可変インピーダンス回路１２０での電圧降下分だけ機器３０に印加される電圧が低減され、機器３０を過電圧から保護することができる。 (4) Features of the sixth embodiment (4-1)
In the overvoltage protection circuit 150, during overvoltage, the voltage applied to the device 30 is reduced by the voltage drop in the variable impedance circuit 120, and the device 30 can be protected from overvoltage.
　（４－２）
　商用電源９０からの供給電圧が過大電圧であっても、可変インピーダンス回路１２０での電圧降下分だけ機器３０に印加される電圧が低減されるので、短時間の過大電圧からの保護だけのために機器３０の電圧定格を高く設計する必要がなく、合理的である。 (4-2)
Even if the supply voltage from the commercial power supply 90 is an excessive voltage, the voltage applied to the device 30 is reduced by the voltage drop in the variable impedance circuit 120, so only for protection from the excessive voltage for a short time. There is no need to design the device 30 with a high voltage rating, which is reasonable.
　＜第７実施形態＞
　（１）過電圧保護回路１５０の構成
　図１７は、本発明の第７実施形態に係る過電圧保護回路１５０を備えた装置の回路図である。図１７において、機器３０は、商用電源９０から一対の電源ライン９０１，９０２を介して電力供給されている。過電圧保護回路１５０は、商用電源９０と機器３０との間に接続されている。 <Seventh embodiment>
(1) Configuration of Overvoltage Protection Circuit 150 FIG. 17 is a circuit diagram of a device including an overvoltage protection circuit 150 according to the seventh embodiment of the present invention. In FIG. 17, the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902. The overvoltage protection circuit 150 is connected between the commercial power supply 90 and the device 30.
　過電圧保護回路１５０は、可変インピーダンス回路１２０と、電圧検出器３３と、第２スイッチ１２とを含んでいる。 The overvoltage protection circuit 150 includes a variable impedance circuit 120, a voltage detector 33, and a second switch 12.
　（２）過電圧保護回路１５０の詳細構成
　第７実施形態は、第５実施形態に第２スイッチ１２が追加された形態であり、可変インピーダンス回路１２０、及び電圧検出器３３については同様のものを採用している。したがって、ここでは第２スイッチ１２についてのみを説明する。 (2) Detailed Configuration of Overvoltage Protection Circuit 150 In the seventh embodiment, the second switch 12 is added to the fifth embodiment, and the variable impedance circuit 120 and the voltage detector 33 are the same. is doing. Therefore, only the second switch 12 will be described here.
　（２－１）第２スイッチ１２
　第２スイッチ１２は、電源ライン９０１を開閉する。ここで、電源ライン９０１を開閉するとは、電源ライン９０１を導通又は遮断して非導通にすることである。 (2-1) Second switch 12
The second switch 12 opens and closes the power line 901. Here, opening and closing the power supply line 901 means that the power supply line 901 is turned on or off to make it non-conductive.
　第２スイッチ１２は、通常時は電源ライン９０１を閉、つまり導通状態にしておく。他方、過電圧時には、可変インピーダンス回路１２０のインピーダンスＺが変化することによって機器３０の保護動作が行われた後に、第２スイッチ１２がオフして電源ライン９０１を遮断する。 The second switch 12 normally closes the power supply line 901, that is, keeps it conductive. On the other hand, at the time of overvoltage, the second switch 12 is turned off and the power supply line 901 is shut off after the protection operation of the device 30 is performed by changing the impedance Z of the variable impedance circuit 120.
　電源ライン９０１を遮断する目的は、電源の過電圧が、可変インピーダンス回路を設計した際の想定電圧以上となった場合や、過電圧状態の継続時間が想定時間以上となった場合に、可変インピーダンス回路１２０での電力消費及び温度上昇を止めるためであり、可変インピーダンス回路１２０の電力定格を小さくすることができ、低コスト化を図ることができる。第２スイッチ１２は、リレー回路が採用されている。 The purpose of cutting off the power supply line 901 is that the variable impedance circuit 120 is used when the overvoltage of the power supply exceeds the assumed voltage when the variable impedance circuit is designed, or when the duration of the overvoltage state exceeds the assumed time. Therefore, the power rating of the variable impedance circuit 120 can be reduced, and the cost can be reduced. The second switch 12 employs a relay circuit.
　図１７に示すように、第２スイッチ１２は、電源ライン９０１を開閉するリレー接点１２ａと、リレー接点１２ａを動作させるリレーコイル１２ｂと、リレーコイル１２ｂへの通電と非通電とを行うトランジスタ１２ｃとを含んでいる。リレーコイル１２ｂの一端は、電源Ｖｂの正極に接続され、他端はトランジスタ１２ｃのコレクタ側に接続されている。制御部４０は、トランジスタ１２ｃのベース電流の有無を切り換えて、コレクタとエミッタ間をオンオフし、リレーコイル１２ｂへの通電と非通電を行う。 As shown in FIG. 17, the second switch 12 includes a relay contact 12a for opening and closing the power supply line 901, a relay coil 12b for operating the relay contact 12a, and a transistor 12c for energizing and de-energizing the relay coil 12b. Is included. One end of the relay coil 12b is connected to the positive electrode of the power source Vb, and the other end is connected to the collector side of the transistor 12c. The control unit 40 switches the presence / absence of the base current of the transistor 12c, turns on / off the collector and the emitter, and energizes and de-energizes the relay coil 12b.
　（３）過電圧保護回路１５０の動作
　図１８は、機器３０のインピーダンスが抵抗成分のみであり、インピーダンスＺが抵抗のみの場合の電圧Ｖの変化を示すグラフである。図１７及び図１８において、通常時、第２スイッチ１２は電源ライン９０１を導通状態にしている。また、可変インピーダンス回路１２０のインピーダンスＺは０若しくは０に近い値であるので、機器３０には電圧Ｖ≒Ｖａｃが印加されている。 (3) Operation of Overvoltage Protection Circuit 150 FIG. 18 is a graph showing changes in the voltage V when the impedance of the device 30 is only the resistance component and the impedance Z is only the resistance. In FIG. 17 and FIG. 18, the second switch 12 keeps the power supply line 901 conductive during normal times. Since the impedance Z of the variable impedance circuit 120 is 0 or a value close to 0, the voltage V≈Vac is applied to the device 30.
　通常時の商用電源９０の電圧ＶａｃがＶ0以下であるとすると、商用電源９０の電圧Ｖａｃが増加し、制御部４０が電圧検出器３３から出力される電圧がＶ0を超えたと判定したとき、制御部４０はインピーダンスＺを電圧検出器３３の検出値の増加に応じて連続的に増加させる。 Assuming that the voltage Vac of the commercial power supply 90 at normal time is equal to or lower than V 0 , the voltage Vac of the commercial power supply 90 increases and the control unit 40 determines that the voltage output from the voltage detector 33 exceeds V 0. The control unit 40 continuously increases the impedance Z in accordance with the increase in the detection value of the voltage detector 33.
　その結果、可変インピーダンス回路１２０の両端における電圧降下分Ｖｚを減じた電圧Ｖ＝Ｖａｃ－Ｖｚが機器３０に印加されることになり、機器３０は過電圧から保護される。 As a result, the voltage V = Vac−Vz obtained by subtracting the voltage drop Vz at both ends of the variable impedance circuit 120 is applied to the device 30, and the device 30 is protected from overvoltage.
　その後、過電圧状態が続いている場合には、商用電源９０の電圧Ｖａｃの上昇に伴って機器３０に印加される電圧Ｖも上昇する。しかし、電圧Ｖａｃが第１閾値Ｖ1に到達したときに第２スイッチ１２が電源ライン９０１を遮断する。この結果、機器３０を保護し、且つ可変インピーダンス回路１２０での電力消費を止める。 Thereafter, when the overvoltage state continues, the voltage V applied to the device 30 increases as the voltage Vac of the commercial power supply 90 increases. However, the second switch 12 cuts off the power supply line 901 when the voltage Vac reaches the first threshold value V 1 . As a result, the device 30 is protected and power consumption in the variable impedance circuit 120 is stopped.
　商用電源９０の電圧Ｖａｃが下がり、電圧検出器３３から出力される電圧が復帰のための閾値よりも下がったと制御部４０が判定したとき、制御部４０は可変インピーダンス回路１２０のインピーダンスＺを０若しくは０に近い値に戻す。さらに、第２スイッチ１２をオンさせて電源ライン９０１を接続することで、通常の動作に復帰する。 When the control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 sets the impedance Z of the variable impedance circuit 120 to 0 or Return to a value close to zero. Further, the second switch 12 is turned on and the power supply line 901 is connected to return to the normal operation.
　（４）第７実施形態の特徴
　（４－１）
　過電圧保護回路１５０では、過電圧時には、可変インピーダンス回路１２０での電圧降下分だけ機器３０に印加される電圧が低減され、機器３０を過電圧から保護することができる。 (4) Features of the seventh embodiment (4-1)
In the overvoltage protection circuit 150, during overvoltage, the voltage applied to the device 30 is reduced by the voltage drop in the variable impedance circuit 120, and the device 30 can be protected from overvoltage.
　（４－２）
　また、第２スイッチ１２が電源ライン９０１を遮断することによって可変インピーダンス回路１２０での電力消費を止める。この結果、可変インピーダンス回路１２０の過熱を抑制し、電力定格を小さくすることができる。 (4-2)
Further, the second switch 12 cuts off the power supply line 901 to stop power consumption in the variable impedance circuit 120. As a result, overheating of the variable impedance circuit 120 can be suppressed and the power rating can be reduced.
　（４－３）
　商用電源９０からの供給電圧が過大電圧であっても、可変インピーダンス回路１２０での電圧降下分だけ機器３０に印加される電圧が低減されるので、短時間の過大電圧からの保護だけのために機器３０の電圧定格を高く設計する必要がなく、合理的である。 (4-3)
Even if the supply voltage from the commercial power supply 90 is an excessive voltage, the voltage applied to the device 30 is reduced by the voltage drop in the variable impedance circuit 120, so only for protection from the excessive voltage for a short time. There is no need to design the device 30 with a high voltage rating, which is reasonable.
　＜第８実施形態＞
　（１）過電圧保護回路１５０の構成
　図１９は、本発明の第８実施形態に係る過電圧保護回路１５０を備えた装置の回路図である。図１９において、機器３０は、商用電源９０から一対の電源ライン９０１，９０２を介して電力供給されている。過電圧保護回路１５０は、商用電源９０と機器３０との間に接続されている。 <Eighth Embodiment>
(1) Configuration of Overvoltage Protection Circuit 150 FIG. 19 is a circuit diagram of a device including an overvoltage protection circuit 150 according to the eighth embodiment of the present invention. In FIG. 19, the device 30 is supplied with power from a commercial power supply 90 via a pair of power supply lines 901 and 902. The overvoltage protection circuit 150 is connected between the commercial power supply 90 and the device 30.
　過電圧保護回路１５０は、可変インピーダンス回路１２０と、電圧検出器３３と、第２スイッチ１２とを含んでいる。 The overvoltage protection circuit 150 includes a variable impedance circuit 120, a voltage detector 33, and a second switch 12.
　（２）過電圧保護回路１５０の詳細構成
　第８実施形態は、可変インピーダンス回路１２０が複数のインピーダンス要素によって構成されている点で上記第７実施形態と相違するが、その他の構成は第７実施形態と同じである。したがって、ここでは可変インピーダンス回路１２０についてのみ説明する。 (2) Detailed Configuration of Overvoltage Protection Circuit 150 The eighth embodiment differs from the seventh embodiment in that the variable impedance circuit 120 is configured by a plurality of impedance elements, but the other configurations are the seventh embodiment. Is the same. Therefore, only the variable impedance circuit 120 will be described here.
　（２－１）可変インピーダンス回路１２０
　可変インピーダンス回路１２０は、低インピーダンス要素１２１、高インピーダンス要素１２２及び切換スイッチ１２３を含んでいる。 (2-1) Variable impedance circuit 120
The variable impedance circuit 120 includes a low impedance element 121, a high impedance element 122, and a changeover switch 123.
　可変インピーダンス回路１２０は、切換スイッチ１２３によって低インピーダンス要素１２１と高インピーダンス要素１２２とを選択的に使用することができる。低インピーダンス要素１２１はインピーダンスＺ1を有している。また、高インピーダンス要素１２２はインピーダンスＺ1よりも大きいインピーダンスＺ2を有している。 The variable impedance circuit 120 can selectively use the low impedance element 121 and the high impedance element 122 by the changeover switch 123. The low impedance element 121 has an impedance Z 1 . The high impedance element 122 has an impedance Z 2 that is greater than the impedance Z 1 .
　可変インピーダンス回路１２０は、低インピーダンス要素１２１の使用時に電圧検出器３３の検出値が所定の閾値を超えたとき、使用するインピーダンス要素を低インピーダンス要素１２１から高インピーダンス要素１２２へ切り換えることができる。 The variable impedance circuit 120 can switch the impedance element to be used from the low impedance element 121 to the high impedance element 122 when the detection value of the voltage detector 33 exceeds a predetermined threshold when the low impedance element 121 is used.
　（３）過電圧保護回路１５０の動作
　図２０は、機器３０のインピーダンスが抵抗成分のみであり、インピーダンスＺが抵抗のみの場合の電圧Ｖの変化を示すグラフである。図１９及び図２０において、通常時、可変インピーダンス回路１２０は、切換スイッチ１２３の接点が低インピーダンス要素１２１に接続されている。低インピーダンス要素１２１のインピーダンスＺ1は０若しくは０に近い値であるので、機器３０には電圧Ｖ≒Ｖａｃが印加されている。 (3) Operation of Overvoltage Protection Circuit 150 FIG. 20 is a graph showing a change in voltage V when the impedance of the device 30 is only a resistance component and the impedance Z is only a resistance. In FIG. 19 and FIG. 20, the variable impedance circuit 120 normally has a contact point of the changeover switch 123 connected to the low impedance element 121. Since the impedance Z 1 of the low impedance element 121 is 0 or a value close to 0, the voltage V≈Vac is applied to the device 30.
　通常時の商用電源９０の電圧Ｖａｃは、Ｖ0以下である。制御部４０は、商用電源９０の電圧Ｖａｃが通常時の値Ｖ0を超えても可変インピーダンス回路１２０の低インピーダンス要素１２１を使用し、インピーダンスＺ1を維持する。 The voltage Vac of the commercial power supply 90 at normal time is V 0 or less. The controller 40 uses the low impedance element 121 of the variable impedance circuit 120 to maintain the impedance Z 1 even when the voltage Vac of the commercial power supply 90 exceeds the normal value V 0 .
　その後、電圧Ｖａｃがさらに上昇し、電圧検出器３３の検出値が第１閾値Ｖ1を超えたとき、制御部４０は切換スイッチ１２３を動作させ、接点を高インピーダンス要素１２２に接続する。 Thereafter, when the voltage Vac further rises and the detection value of the voltage detector 33 exceeds the first threshold value V 1 , the control unit 40 operates the changeover switch 123 to connect the contact point to the high impedance element 122.
　高インピーダンス要素１２２のインピーダンスＺ2は低インピーダンス要素１２１のインピーダンスＺ1より大きいので、可変インピーダンス回路１２０の両端における電圧降下分Ｖｚが増加し、電圧Ｖ＝Ｖａｃ－Ｖｚが機器３０に印加されることになる。 Since the impedance Z 2 of the high impedance element 122 is larger than the impedance Z 1 of the low impedance element 121, the voltage drop Vz at both ends of the variable impedance circuit 120 increases, and the voltage V = Vac−Vz is applied to the device 30. become.
　その結果、機器３０に印加される電圧ＶがＶ1からＶ0へ減少し、機器３０は過電圧から保護される。 As a result, the voltage V applied to the device 30 decreases from V 1 to V 0 , and the device 30 is protected from overvoltage.
　その後、過電圧状態が続いている場合には、商用電源９０の電圧Ｖａｃの上昇に伴って機器３０に印加される電圧Ｖも上昇する。しかし、電圧Ｖａｃが第２閾値Ｖ2（Ｖ2＝Ｖ1でもよい）に到達したときに第２スイッチ１２が電源ライン９０１を遮断する。この結果、機器３０を保護し、且つ可変インピーダンス回路１２０での電力消費を止める。 Thereafter, when the overvoltage state continues, the voltage V applied to the device 30 increases as the voltage Vac of the commercial power supply 90 increases. However, the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches the second threshold value V 2 (V 2 = V 1 may be used). As a result, the device 30 is protected and power consumption in the variable impedance circuit 120 is stopped.
　商用電源９０の電圧Ｖａｃが下がり、電圧検出器３３から出力される電圧が復帰のための閾値よりも下がったと制御部４０が判定したとき、制御部４０は可変インピーダンス回路１２０のインピーダンス要素を高インピーダンス要素１２２から低インピーダンス要素１２１へ切り換えて、インピーダンスＺ2をインピーダンスＺ1に戻す。さらに、第２スイッチ１２をオンさせて電源ライン９０１を接続することで、通常の動作に復帰する。 When the control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 sets the impedance element of the variable impedance circuit 120 to a high impedance Switching from element 122 to low impedance element 121 returns impedance Z 2 to impedance Z 1 . Further, the second switch 12 is turned on and the power supply line 901 is connected to return to the normal operation.
　（４）第８実施形態の特徴
　（４－１）
　過電圧保護回路１５０では、過電圧時に、可変インピーダンス回路１２０のインピーダンス要素を低インピーダンス要素１２１から高インピーダンス要素１２２へ切り換えるので、インピーダンスＺ2での電圧降下分だけ機器３０に印加される電圧が低減され、機器３０を過電圧から保護することができる。 (4) Features of the eighth embodiment (4-1)
The overvoltage protection circuit 150 switches the impedance element of the variable impedance circuit 120 from the low impedance element 121 to the high impedance element 122 at the time of overvoltage, so that the voltage applied to the device 30 is reduced by the voltage drop at the impedance Z 2 . The device 30 can be protected from overvoltage.
　（４－２）
　また、第２スイッチ１２が電源ライン９０１を遮断することによって可変インピーダンス回路１２０での電力消費を止める。この結果、可変インピーダンス回路１２０の過熱を抑制し、電力定格を小さくすることができる。 (4-2)
Further, the second switch 12 cuts off the power supply line 901 to stop power consumption in the variable impedance circuit 120. As a result, overheating of the variable impedance circuit 120 can be suppressed and the power rating can be reduced.
　（４－３）
　商用電源９０からの供給電圧が過大電圧であっても、可変インピーダンス回路１２０での電圧降下分だけ機器３０に印加される電圧が低減されるので、短時間の過大電圧からの保護だけのために機器３０の電圧定格を高く設計する必要がなく、合理的である。 (4-3)
Even if the supply voltage from the commercial power supply 90 is an excessive voltage, the voltage applied to the device 30 is reduced by the voltage drop in the variable impedance circuit 120, so only for protection from the excessive voltage for a short time. There is no need to design the device 30 with a high voltage rating, which is reasonable.
　＜第９実施形態＞
　（１）電力変換装置３００の構成
　図２１は、本発明の第９実施形態に係る過電圧保護回路２００を備えた電力変換装置３００の回路図である。図２１において、電力変換装置３００は、直流電源部８０、インバータ９５、過電圧保護回路２００で構成されている。 <Ninth Embodiment>
(1) Configuration of Power Converter 300 FIG. 21 is a circuit diagram of a power converter 300 including an overvoltage protection circuit 200 according to the ninth embodiment of the present invention. In FIG. 21, the power conversion device 300 includes a DC power supply unit 80, an inverter 95, and an overvoltage protection circuit 200.
　インバータ９５は、直流電源部８０から一対の電源ライン８０１，８０２を介して電力供給されている。過電圧保護回路２００は、直流電源部８０とインバータ９５との間に接続されている。 The inverter 95 is supplied with power from the DC power supply unit 80 via a pair of power supply lines 801 and 802. The overvoltage protection circuit 200 is connected between the DC power supply unit 80 and the inverter 95.
　（１－１）直流電源部８０
　直流電源部８０は、整流部８１と、整流部８１と並列接続される平滑コンデンサ８２とで構成されている。 (1-1) DC power supply unit 80
The DC power supply unit 80 includes a rectifying unit 81 and a smoothing capacitor 82 connected in parallel with the rectifying unit 81.
　整流部８１は、４つのダイオードＤ１ａ，Ｄ１ｂ，Ｄ２ａ，Ｄ２ｂによってブリッジ状に構成されている。具体的には、ダイオードＤ１ａとＤ１ｂ、Ｄ２ａとＤ２ｂは、それぞれ互いに直列に接続されている。ダイオードＤ１ａ，Ｄ２ａの各カソード端子は、共に平滑コンデンサ８２のプラス側端子に接続されており、整流部８１の正側出力端子として機能する。ダイオードＤ１ｂ，Ｄ２ｂの各ダイオードの各アノード端子は、共に平滑コンデンサ８２のマイナス側端子に接続されており、整流部８１の負側出力端子として機能する。 The rectifying unit 81 is configured in a bridge shape by four diodes D1a, D1b, D2a, and D2b. Specifically, the diodes D1a and D1b and D2a and D2b are respectively connected in series. The cathode terminals of the diodes D1a and D2a are both connected to the plus side terminal of the smoothing capacitor 82 and function as the positive side output terminal of the rectifying unit 81. The anode terminals of the diodes D1b and D2b are both connected to the minus terminal of the smoothing capacitor 82 and function as the negative output terminal of the rectifier 81.
　ダイオードＤ１ａ及びダイオードＤ１ｂの接続点は、商用電源９０の一方の極に接続されている。ダイオードＤ２ａ及びダイオードＤ２ｂの接続点は、商用電源９０の他方の極に接続されている。整流部８１は、商用電源９０から出力される交流電圧を整流して直流電圧を生成し、これを平滑コンデンサ８２へ供給する。 The connection point of the diode D1a and the diode D1b is connected to one pole of the commercial power supply 90. A connection point between the diode D2a and the diode D2b is connected to the other pole of the commercial power supply 90. The rectifying unit 81 rectifies the AC voltage output from the commercial power supply 90 to generate a DC voltage, and supplies this to the smoothing capacitor 82.
　平滑コンデンサ８２は、整流部８１によって整流された電圧を平滑する。平滑後の電圧Ｖｄｃは、平滑コンデンサ８２の出力側に接続されるインバータ９５へ印加される。 The smoothing capacitor 82 smoothes the voltage rectified by the rectifying unit 81. The smoothed voltage Vdc is applied to the inverter 95 connected to the output side of the smoothing capacitor 82.
　なお、コンデンサの種類としては、電解コンデンサやフィルムコンデンサ等が挙げられるが、本実施形態においては、平滑コンデンサ８２として電解コンデンサが採用される。 In addition, although an electrolytic capacitor, a film capacitor, etc. are mentioned as a kind of capacitor | condenser, in this embodiment, an electrolytic capacitor is employ | adopted as the smoothing capacitor 82. FIG.
　この直流電源部８０は、交流電圧を直流電圧に変換するコンバータ回路と言い換えることもできる。 The DC power supply unit 80 can be rephrased as a converter circuit that converts an AC voltage into a DC voltage.
　（１－２）インバータ９５
　インバータ９５は、複数のＩＧＢＴ（絶縁ゲート型バイポーラトランジスタ、以下、単にトランジスタという）及び複数の還流用ダイオードを含んでいる。インバータ９５は、平滑コンデンサ８２からの電圧Ｖｄｃが印加され、かつゲート駆動回路９６により指示されたタイミングで各トランジスタがオン及びオフを行うことによって、モータ５００を駆動する駆動電圧を生成する。モータ５００は、例えばヒートポンプ式空気調和機の圧縮機モータ、ファンモータである。 (1-2) Inverter 95
The inverter 95 includes a plurality of IGBTs (insulated gate bipolar transistors, hereinafter simply referred to as transistors) and a plurality of free-wheeling diodes. The inverter 95 is applied with the voltage Vdc from the smoothing capacitor 82, and each transistor is turned on and off at the timing instructed by the gate drive circuit 96, thereby generating a drive voltage for driving the motor 500. The motor 500 is, for example, a compressor motor or a fan motor of a heat pump type air conditioner.
　なお、本実施形態のインバータ９５は、電圧形インバータであるが、それに限定されるものではなく、電流形インバータでもよい。 In addition, although the inverter 95 of this embodiment is a voltage source inverter, it is not limited to it, A current source inverter may be sufficient.
　（１－３）ゲート駆動回路９６
　ゲート駆動回路９６は、制御部４０からの指令に基づき、インバータ９５の各トランジスタのオン及びオフの状態を変化させる。 (1-3) Gate drive circuit 96
The gate drive circuit 96 changes the on / off state of each transistor of the inverter 95 based on a command from the control unit 40.
　（１－４）過電圧保護回路２００
　過電圧保護回路２００は、可変インピーダンス回路１７０と、電圧検出器８３と、第２スイッチ６２とを含んでいる。 (1-4) Overvoltage protection circuit 200
The overvoltage protection circuit 200 includes a variable impedance circuit 170, a voltage detector 83, and a second switch 62.
　（２）過電圧保護回路２００の詳細構成
　第９実施形態と、既に説明した第７実施形態及び第８実施形態と大きく異なる点は、過電圧保護回路２００が直流部に設けられていることである。したがって、各構成要素も交流仕様から直流仕様に置き換えられることに鑑みて、同一名称であっても符号を換えて、再度説明する。 (2) Detailed Configuration of Overvoltage Protection Circuit 200 The ninth embodiment is different from the seventh embodiment and the eighth embodiment already described in that the overvoltage protection circuit 200 is provided in the direct current section. Therefore, in view of the fact that each component is also replaced from the AC specification to the DC specification, the description will be given again by changing the code even if the names are the same.
　（２－１）可変インピーダンス回路１７０
　可変インピーダンス回路１７０は、当該回路における電圧と電流との比であるインピーダンスがＺとなるように構成された回路である。一般に抵抗素子が採用される。 (2-1) Variable impedance circuit 170
The variable impedance circuit 170 is a circuit configured such that an impedance that is a ratio of a voltage and a current in the circuit is Z. In general, a resistance element is employed.
　可変インピーダンス回路１７０は、電源ライン８０２上で、直流電源部８０とインバータ９５との間に接続されている。 The variable impedance circuit 170 is connected between the DC power supply unit 80 and the inverter 95 on the power supply line 802.
　可変インピーダンス回路１７０は、低インピーダンス要素１７１、高インピーダンス要素１７２及び切換スイッチ１７３を含んでいる。 The variable impedance circuit 170 includes a low impedance element 171, a high impedance element 172, and a changeover switch 173.
　可変インピーダンス回路１７０は、切換スイッチ１７３によって低インピーダンス要素１７１と高インピーダンス要素１７２とを選択的に使用することができる。低インピーダンス要素１７１はインピーダンスＺ1を有している。また、高インピーダンス要素１７２はインピーダンスＺ1よりも大きいインピーダンスＺ2を有している。 The variable impedance circuit 170 can selectively use the low impedance element 171 and the high impedance element 172 by the changeover switch 173. Low impedance element 171 has an impedance Z 1. The high impedance element 172 has an impedance Z 2 that is greater than the impedance Z 1 .
　可変インピーダンス回路１７０は、低インピーダンス要素１７１の使用時に電圧検出器８３の検出値が所定の閾値を超えたとき、使用するインピーダンス要素を低インピーダンス要素１７１から高インピーダンス要素１７２へ切り換えることができる。 The variable impedance circuit 170 can switch the impedance element to be used from the low impedance element 171 to the high impedance element 172 when the detection value of the voltage detector 83 exceeds a predetermined threshold when the low impedance element 171 is used.
　（２－２）電圧検出器８３
　電圧検出器８３は、平滑コンデンサ８２の出力側に接続されており、平滑コンデンサ８２の両端電圧、即ち平滑後の電圧Ｖｄｃの値を検出する。電圧検出器８３は、例えば、互いに直列に接続された２つの抵抗が平滑コンデンサ８２に並列接続され、電圧Ｖｄｃが分圧されるように構成される。それら２つの抵抗同士の接続点の電圧値は、制御部４０に入力される。 (2-2) Voltage detector 83
The voltage detector 83 is connected to the output side of the smoothing capacitor 82, and detects the voltage across the smoothing capacitor 82, that is, the value of the smoothed voltage Vdc. For example, the voltage detector 83 is configured such that two resistors connected in series with each other are connected in parallel to the smoothing capacitor 82 and the voltage Vdc is divided. The voltage value at the connection point between the two resistors is input to the control unit 40.
　（２－３）第２スイッチ６２
　第２スイッチ６２は、電源ライン８０１を開閉する。ここで、電源ライン８０１を開閉するとは、電源ライン８０１を導通又は遮断して非導通にすることである。 (2-3) Second switch 62
The second switch 62 opens and closes the power line 801. Here, opening and closing the power supply line 801 is to turn the power supply line 801 on or off to make it non-conductive.
　第２スイッチ６２は、通常時は電源ライン８０１を閉、つまり導通状態にしておく。他方、過電圧時には、可変インピーダンス回路１７０のインピーダンスＺが変化することによってインバータ９５の保護動作が行われた後に、第２スイッチ６２がオフして電源ライン８０１を遮断する。 The second switch 62 normally closes the power supply line 801, that is, keeps it conductive. On the other hand, at the time of overvoltage, the second switch 62 is turned off and the power supply line 801 is shut off after the protection operation of the inverter 95 is performed by the impedance Z of the variable impedance circuit 170 changing.
　電源ライン８０１を遮断する目的は、可変インピーダンス回路１７０での電力消費を止めるためであり、可変インピーダンス回路１７０の電力定格を小さくすることができ、低コスト化を図ることができる。第２スイッチ６２は、リレー回路が採用されている。 The purpose of cutting off the power supply line 801 is to stop the power consumption in the variable impedance circuit 170, the power rating of the variable impedance circuit 170 can be reduced, and the cost can be reduced. The second switch 62 employs a relay circuit.
　図２１に示すように、第２スイッチ６２は、電源ライン８０１を開閉するリレー接点６２ａと、リレー接点６２ａを動作させるリレーコイル６２ｂと、リレーコイル６２ｂへの通電と非通電とを行うトランジスタ６２ｃとを含んでいる。リレーコイル６２ｂの一端は、電源Ｖｂの正極に接続され、他端はトランジスタ６２ｃのコレクタ側に接続されている。制御部４０は、トランジスタ６２ｃのベース電流の有無を切り換えて、コレクタとエミッタ間をオンオフし、リレーコイル６２ｂへの通電と非通電を行う。 As shown in FIG. 21, the second switch 62 includes a relay contact 62a for opening and closing the power supply line 801, a relay coil 62b for operating the relay contact 62a, and a transistor 62c for energizing and de-energizing the relay coil 62b. Is included. One end of the relay coil 62b is connected to the positive electrode of the power supply Vb, and the other end is connected to the collector side of the transistor 62c. The controller 40 switches between the presence and absence of the base current of the transistor 62c, turns on and off the collector and the emitter, and performs energization and de-energization of the relay coil 62b.
　（３）過電圧保護回路２００の動作
　図２１において、通常時、第２スイッチ６２は電源ライン８０１を導通状態にしている。また、通常時、可変インピーダンス回路１７０は、切換スイッチ１７３の接点が低インピーダンス要素１７１に接続されている。低インピーダンス要素１７１のインピーダンスＺ1は０若しくは０に近い値であるので、インバータ９５には電圧Ｖ≒Ｖｄｃが印加されている。 (3) Operation of Overvoltage Protection Circuit 200 In FIG. 21, the second switch 62 keeps the power supply line 801 conductive during normal operation. In the normal state, the variable impedance circuit 170 has a contact point of the changeover switch 173 connected to the low impedance element 171. Since the impedance Z 1 of the low impedance element 171 is 0 or a value close to 0, the voltage V≈Vdc is applied to the inverter 95.
　直流電源部８０の電圧Ｖｄｃが増加し、電圧検出器８３の検出値が第１閾値を超えたとき、制御部４０は切換スイッチ１７３を動作させ、接点を高インピーダンス要素１７２に接続する。 When the voltage Vdc of the DC power supply unit 80 increases and the detection value of the voltage detector 83 exceeds the first threshold value, the control unit 40 operates the changeover switch 173 to connect the contact point to the high impedance element 172.
　高インピーダンス要素１７２のインピーダンスＺ2は低インピーダンス要素１７１のインピーダンスＺ1より大きいので、可変インピーダンス回路１７０の両端における電圧降下分Ｖｚが増加し、電圧Ｖ＝Ｖｄｃ－Ｖｚがインバータ９５に印加されることになる。その結果、インバータ９５に印加される電圧Ｖが減少し、インバータ９５が過電圧から保護される。 Since the impedance Z 2 of the high impedance element 172 is larger than the impedance Z 1 of the low impedance element 171, the voltage drop Vz at both ends of the variable impedance circuit 170 increases and the voltage V = Vdc−Vz is applied to the inverter 95. become. As a result, the voltage V applied to the inverter 95 decreases, and the inverter 95 is protected from overvoltage.
　その後、過電圧状態が続いている場合には、インバータ９５に印加される電圧Ｖも上昇する。しかし、直流電源部８０の電圧Ｖｄｃが第２閾値（＝第１閾値でもよい）に到達したときに第２スイッチ６２が電源ライン８０１を遮断する。その結果、インバータ９５が過電圧から保護され、且つ可変インピーダンス回路１７０での電力消費が止まる。 Thereafter, when the overvoltage state continues, the voltage V applied to the inverter 95 also increases. However, the second switch 62 cuts off the power supply line 801 when the voltage Vdc of the DC power supply unit 80 reaches the second threshold (or may be the first threshold). As a result, the inverter 95 is protected from overvoltage and the power consumption in the variable impedance circuit 170 is stopped.
　直流電源部８０の電圧Ｖｄｃが下がり、電圧検出器８３から出力される電圧が復帰のための閾値よりも下がったと制御部４０が判定したとき、制御部４０は可変インピーダンス回路１７０のインピーダンス要素を高インピーダンス要素１７２から低インピーダンス要素１７１へ切り換えて、インピーダンスＺ2をインピーダンスＺ1に戻す。さらに、第２スイッチ６２をオンさせて電源ライン８０１を接続することで、通常の動作に復帰する。 When the control unit 40 determines that the voltage Vdc of the DC power supply unit 80 has dropped and the voltage output from the voltage detector 83 has fallen below the threshold for recovery, the control unit 40 increases the impedance element of the variable impedance circuit 170 to a high level. Switching from the impedance element 172 to the low impedance element 171 returns the impedance Z 2 to the impedance Z 1 . Further, by turning on the second switch 62 and connecting the power supply line 801, the normal operation is restored.
　（４）第９実施形態の特徴
　（４－１）
　過電圧保護回路２００では、過電圧時に、可変インピーダンス回路１７０のインピーダンス要素を高インピーダンス要素１７２へ切り換えることによって、インピーダンスＺ2での電圧降下分だけインバータ９５に印加される電圧が低減され、インバータ９５を過電圧から保護することができる。 (4) Features of the ninth embodiment (4-1)
The overvoltage protection circuit 200, during an overvoltage, by switching the impedance components of the variable impedance circuit 170 to a high impedance element 172, the voltage applied to the voltage drop by the inverter 95 in the impedance Z 2 is reduced, the overvoltage inverters 95 Can be protected from.
　（４－２）
　また、第２スイッチ６２が電源ライン８０１を遮断することによって可変インピーダンス回路１７０での電力消費を止める。この結果、可変インピーダンス回路１７０の電力定格を小さくすることができる。 (4-2)
Further, the second switch 62 cuts off the power supply line 801 to stop the power consumption in the variable impedance circuit 170. As a result, the power rating of the variable impedance circuit 170 can be reduced.
　＜第１０実施形態＞
　（１）過電圧保護回路２００の構成
　図２２は、本発明の第１０実施形態に係る過電圧保護回路２００を備えた電力変換装置３００の回路図である。図２２において、インバータ９５は、直流電源部８０から一対の電源ライン８０１，８０２を介して電力供給されている。過電圧保護回路２００の一部は商用電源９０と直流電源部８０との間に接続され、他の部分は直流電源部８０とインバータ９５との間に接続されている。 <Tenth Embodiment>
(1) Configuration of Overvoltage Protection Circuit 200 FIG. 22 is a circuit diagram of a power conversion device 300 including the overvoltage protection circuit 200 according to the tenth embodiment of the present invention. In FIG. 22, the inverter 95 is supplied with power from a DC power supply unit 80 via a pair of power supply lines 801 and 802. A part of the overvoltage protection circuit 200 is connected between the commercial power supply 90 and the DC power supply unit 80, and the other part is connected between the DC power supply unit 80 and the inverter 95.
　過電圧保護回路２００は、可変インピーダンス回路１７０と、電圧検出器３３、第２スイッチ１２とを含んでいる。 The overvoltage protection circuit 200 includes a variable impedance circuit 170, a voltage detector 33, and a second switch 12.
　第１０実施形態と、既に説明した第９実施形態と異なる点は、過電圧保護回路２００の構成要素である電圧検出器と第２スイッチとが商用電源９０と直流電源部８０との間に設けられていることである。つまり、電圧検出器及び第２スイッチの配置が、第８実施形態における電圧検出器３３及び第２スイッチ１２の配置と同じである。したがって、電圧検出器及び第２スイッチが直流仕様から交流仕様に置き換えられることに鑑みて、第８実施形態の電圧検出器３３及び第２スイッチ１２が採用されている。 The difference between the tenth embodiment and the already described ninth embodiment is that a voltage detector, which is a component of the overvoltage protection circuit 200, and a second switch are provided between the commercial power supply 90 and the DC power supply unit 80. It is that. That is, the arrangement of the voltage detector and the second switch is the same as the arrangement of the voltage detector 33 and the second switch 12 in the eighth embodiment. Therefore, in view of the fact that the voltage detector and the second switch are replaced from the DC specification to the AC specification, the voltage detector 33 and the second switch 12 of the eighth embodiment are employed.
　したがって、各構成要素の内容は、第８実施形態の電圧検出器３３及び第２スイッチ１２、第９実施形態の可変インピーダンス回路１７０と同様であるので、ここでは説明を省略し、動作説明のみ行う。 Therefore, the content of each component is the same as that of the voltage detector 33 and the second switch 12 of the eighth embodiment and the variable impedance circuit 170 of the ninth embodiment. .
　（２）過電圧保護回路２００の動作
　図２２において、通常時、第２スイッチ１２は電源ライン９０１を導通状態にしている。また、通常時、可変インピーダンス回路１７０は、切換スイッチ１７３の接点が低インピーダンス要素１７１に接続されている。低インピーダンス要素１７１のインピーダンスＺ1は０若しくは０に近い値であるので、インバータ９５には電圧Ｖ≒Ｖｄｃが印加されている。 (2) Operation of Overvoltage Protection Circuit 200 In FIG. 22, the second switch 12 keeps the power supply line 901 conductive during normal operation. In the normal state, the variable impedance circuit 170 has a contact point of the changeover switch 173 connected to the low impedance element 171. Since the impedance Z 1 of the low impedance element 171 is 0 or a value close to 0, the voltage V≈Vdc is applied to the inverter 95.
　商用電源９０の電圧Ｖａｃの変動により、直流電源部８０の電圧Ｖｄｃが増加し、電圧検出器３３の検出値が第１閾値を超えたとき、制御部４０は切換スイッチ１７３を動作させ、接点を高インピーダンス要素１７２に接続する。 When the voltage Vdc of the DC power supply unit 80 increases due to the fluctuation of the voltage Vac of the commercial power supply 90 and the detected value of the voltage detector 33 exceeds the first threshold value, the control unit 40 operates the changeover switch 173 to change the contact point. Connect to high impedance element 172.
　高インピーダンス要素１７２のインピーダンスＺ2は低インピーダンス要素１７１のインピーダンスＺ1より大きいので、可変インピーダンス回路１７０の両端における電圧降下分Ｖｚが増加し、電圧Ｖ＝Ｖｄｃ－Ｖｚがインバータ９５に印加されることになる。その結果、インバータ９５に印加される電圧Ｖが減少し、インバータ９５が過電圧から保護される。 Since the impedance Z 2 of the high impedance element 172 is larger than the impedance Z 1 of the low impedance element 171, the voltage drop Vz at both ends of the variable impedance circuit 170 increases and the voltage V = Vdc−Vz is applied to the inverter 95. become. As a result, the voltage V applied to the inverter 95 decreases, and the inverter 95 is protected from overvoltage.
　その後、過電圧状態が続いている場合には、インバータ９５に印加される電圧Ｖも上昇する。しかし、電圧検出器３３の検出値が第２閾値（＝第１閾値でもよい）に到達したときに第２スイッチ１２が電源ライン９０１を遮断する。その結果、インバータ９５が過電圧から保護され、且つ可変インピーダンス回路１７０での電力消費が止まる。 Thereafter, when the overvoltage state continues, the voltage V applied to the inverter 95 also increases. However, the second switch 12 shuts off the power supply line 901 when the detection value of the voltage detector 33 reaches the second threshold (= may be the first threshold). As a result, the inverter 95 is protected from overvoltage and the power consumption in the variable impedance circuit 170 is stopped.
　商用電源９０の電圧Ｖａｃが安定し、直流電源部８０の電圧Ｖｄｃが下がり、電圧検出器３３から出力される電圧が復帰のための閾値よりも下がったと制御部４０が判定したとき、制御部４０は可変インピーダンス回路１７０のインピーダンス要素を高インピーダンス要素１７２から低インピーダンス要素１７１へ切り換えて、インピーダンスＺ2をインピーダンスＺ1に戻す。さらに、第２スイッチ１２をオンさせて電源ライン９０１を接続することで、通常の動作に復帰する。 When the control unit 40 determines that the voltage Vac of the commercial power supply 90 is stable, the voltage Vdc of the DC power supply unit 80 is decreased, and the voltage output from the voltage detector 33 is lower than the threshold for recovery, the control unit 40 Switches the impedance element of the variable impedance circuit 170 from the high impedance element 172 to the low impedance element 171 to return the impedance Z 2 to the impedance Z 1 . Further, the second switch 12 is turned on and the power supply line 901 is connected to return to the normal operation.
　（３）第１０実施形態の特徴
　（３－１）
　過電圧保護回路２００では、過電圧時に、可変インピーダンス回路１７０のインピーダンス要素を高インピーダンス要素１７２へ切り換えることによって、インピーダンスＺ2での電圧降下分だけインバータ９５に印加される電圧が低減され、インバータ９５を過電圧から保護することができる。 (3) Features of the tenth embodiment (3-1)
The overvoltage protection circuit 200, during an overvoltage, by switching the impedance components of the variable impedance circuit 170 to a high impedance element 172, the voltage applied to the voltage drop by the inverter 95 in the impedance Z 2 is reduced, the overvoltage inverters 95 Can be protected from.
　（３－２）
　また、第２スイッチ１２が電源ライン９０１を遮断することによって可変インピーダンス回路１７０での電力消費を止める。この結果、可変インピーダンス回路１７０の過熱を抑制し、電力定格を小さくすることができる。 (3-2)
Further, the second switch 12 cuts off the power supply line 901 to stop power consumption in the variable impedance circuit 170. As a result, overheating of the variable impedance circuit 170 can be suppressed and the power rating can be reduced.
　＜その他の変形例＞
　（Ａ）
　図１に示す第５実施形態に係る過電圧保護回路１５０は、交流電圧に対する過電圧保護回路を実施形態としているが、電源が直流電源である場合、あるいは機器内に交流電源を整流する直流電源部を持つ場合には、各構成要素を交流仕様から直流仕様へ置き換えて直流電源部の下流側に設けてもよい。 <Other variations>
(A)
The overvoltage protection circuit 150 according to the fifth embodiment shown in FIG. 1 has an overvoltage protection circuit for an AC voltage as an embodiment. However, when the power supply is a DC power supply, or a DC power supply unit that rectifies the AC power supply in the device. In the case of having it, each component may be replaced from the AC specification to the DC specification and provided on the downstream side of the DC power supply unit.
　（Ｂ）
　第８実施形態では、電圧Ｖａｃが所定の第２閾値に達したときに第２スイッチ１２が電源ライン９０１を遮断したが、過電圧状態が所定の継続時間を経過したときに遮断するようにしてもよい。 (B)
In the eighth embodiment, the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches a predetermined second threshold value, but it may be cut off when the overvoltage state has passed a predetermined duration. Good.
　（Ｃ）
　第８実施形態では、電圧Ｖａｃが所定の第２閾値に達したときに第２スイッチ１２が電源ライン９０１を遮断したが、機器に印加される電圧Ｖを検出する機器電圧検出器３７を更に設け、電圧Ｖが所定の第３閾値に達したときに遮断するようにしてもよい。 (C)
In the eighth embodiment, the second switch 12 shuts off the power supply line 901 when the voltage Vac reaches a predetermined second threshold, but a device voltage detector 37 for detecting the voltage V applied to the device is further provided. The voltage V may be cut off when it reaches a predetermined third threshold value.
　図２３は、他の変形例に係る過電圧保護回路１５０を備えた装置の回路図である。また、図２４は、インピーダンスが抵抗のみの場合の電圧Ｖの変化を示すグラフである。図２３及び図２４において、通常時、可変インピーダンス回路１２０は、切換スイッチ１２３の接点が低インピーダンス要素１２１に接続されている。低インピーダンス要素１２１のインピーダンスＺ1は０若しくは０に近い値であるので、機器３０には電圧Ｖ≒Ｖａｃが印加されている。 FIG. 23 is a circuit diagram of an apparatus including an overvoltage protection circuit 150 according to another modification. FIG. 24 is a graph showing changes in voltage V when the impedance is only resistance. 23 and 24, the variable impedance circuit 120 is normally connected to the low impedance element 121 at the contact point of the changeover switch 123 in the variable impedance circuit 120. Since the impedance Z 1 of the low impedance element 121 is 0 or a value close to 0, the voltage V≈Vac is applied to the device 30.
　制御部４０は、商用電源９０の電圧Ｖａｃが通常時の値Ｖ0を超えても可変インピーダンス回路１２０の低インピーダンス要素１２１を使用し、インピーダンスＺ1を維持する。 The controller 40 uses the low impedance element 121 of the variable impedance circuit 120 to maintain the impedance Z 1 even when the voltage Vac of the commercial power supply 90 exceeds the normal value V 0 .
　その後、電圧Ｖａｃがさらに上昇し、電圧検出器３３の検出値が第１閾値Ｖ1を超えたとき、制御部４０は切換スイッチ１２３を動作させ、接点を高インピーダンス要素１２２に接続する。 Thereafter, when the voltage Vac further rises and the detection value of the voltage detector 33 exceeds the first threshold value V 1 , the control unit 40 operates the changeover switch 123 to connect the contact point to the high impedance element 122.
　高インピーダンス要素１２２のインピーダンスＺ2は低インピーダンス要素１２１のインピーダンスＺ1より大きいので、可変インピーダンス回路１２０の両端における電圧降下分Ｖｚが増加し、電圧Ｖ＝Ｖａｃ－Ｖｚが機器３０に印加されることになる。その結果、機器３０に印加される電圧Ｖが減少し、機器３０は過電圧から保護される。 Since the impedance Z 2 of the high impedance element 122 is larger than the impedance Z 1 of the low impedance element 121, the voltage drop Vz at both ends of the variable impedance circuit 120 increases, and the voltage V = Vac−Vz is applied to the device 30. become. As a result, the voltage V applied to the device 30 decreases, and the device 30 is protected from overvoltage.
　その後、制御部４０は切換スイッチ１２３の接点を高インピーダンス要素１２２に接続した状態を維持するが、過電圧状態が続いている場合には、図２４に示すように商用電源９０の電圧Ｖａｃの上昇に伴って機器３０に印加される電圧Ｖも上昇する。 Thereafter, the control unit 40 maintains the state in which the contact of the changeover switch 123 is connected to the high impedance element 122. However, if the overvoltage state continues, the control unit 40 increases the voltage Vac of the commercial power supply 90 as shown in FIG. Along with this, the voltage V applied to the device 30 also increases.
　そして、機器電圧検出器３７の検出値が閾値Ｖmに到達したとき、制御部４０は第２スイッチ１２を介して電源ライン９０１を遮断する。この結果、機器３０を保護し、且つ可変インピーダンス回路１２０での電力消費及び温度上昇を止めることができる。 When the detection value of the device voltage detector 37 reaches the threshold value V m , the control unit 40 shuts off the power supply line 901 via the second switch 12. As a result, the device 30 can be protected, and power consumption and temperature rise in the variable impedance circuit 120 can be stopped.
　商用電源９０の電圧Ｖａｃが下がり、電圧検出器３３から出力される電圧が復帰のための閾値よりも下がったと制御部４０が判定したとき、制御部４０は可変インピーダンス回路１２０のインピーダンス要素を高インピーダンス要素１２２から低インピーダンス要素１２１へ切り換えて、インピーダンスＺ2をインピーダンスＺ1に戻す。さらに、第２スイッチ１２をオンさせて電源ライン９０１を接続することで、通常の動作に復帰する。 When the control unit 40 determines that the voltage Vac of the commercial power supply 90 has dropped and the voltage output from the voltage detector 33 has fallen below the threshold for recovery, the control unit 40 sets the impedance element of the variable impedance circuit 120 to a high impedance Switching from element 122 to low impedance element 121 returns impedance Z 2 to impedance Z 1 . Further, the second switch 12 is turned on and the power supply line 901 is connected to return to the normal operation.
　（Ｄ）
　第１０実施形態は、第９実施形態の電圧検出器と第２スイッチとを、商用電源９０と直流電源部８０との間に設けるように変更したものであるが、電圧検出器のみを商用電源９０と直流電源部８０との間に設けるようにしてもよい。 (D)
In the tenth embodiment, the voltage detector and the second switch of the ninth embodiment are changed to be provided between the commercial power supply 90 and the DC power supply unit 80, but only the voltage detector is used as the commercial power supply. 90 and the DC power supply unit 80 may be provided.
　（Ｅ）
　第９実施形態、第１０実施形態では、機器の内部に過電圧保護回路を持つ例を示したが、機器はコンバータ回路とインバータ回路を持つものに限定されない。 (E)
In the ninth embodiment and the tenth embodiment, the example in which the overvoltage protection circuit is provided inside the device has been described, but the device is not limited to the one having the converter circuit and the inverter circuit.
　（Ｆ）
　第６実施形態及び第８実施形態において、切換スイッチ１２３を用いる構成に替えて、第１実施形態におけるスイッチ１１を低インピーダンス要素１２１及び高インピーダンス要素１２２それぞれに直列接続して、電圧検出器３３の検出電圧に応じてオンさせるスイッチを切り換えてもよい。 (F)
In the sixth embodiment and the eighth embodiment, instead of the configuration using the changeover switch 123, the switch 11 in the first embodiment is connected in series to the low impedance element 121 and the high impedance element 122, respectively. A switch to be turned on may be switched according to the detection voltage.
　（Ｇ）
　第９実施形態及び第１０実施形態において、切換スイッチ１７３を用いる構成に替えて、第３実施形態におけるスイッチ７１を低インピーダンス要素１７１及び高インピーダンス要素１７２それぞれに直列接続して、電圧検出器８３の検出電圧に応じてオンさせるスイッチを切り換えてもよい。 (G)
In the ninth and tenth embodiments, instead of the configuration using the changeover switch 173, the switch 71 in the third embodiment is connected in series to the low impedance element 171 and the high impedance element 172, and the voltage detector 83 A switch to be turned on may be switched according to the detection voltage.
　本発明は、電源電圧の変動が起こり易い地域で使用される機器、例えば、冷凍装置に有用である。 The present invention is useful for equipment used in an area where power supply voltage is likely to fluctuate, such as a refrigeration apparatus.
１１，６１　　　スイッチ
１２，６２　　　第２スイッチ
２０，７０　　　インピーダンス回路
３３，８３　　　電圧検出器
３５，８５　　　バイパス回路
３７　　　　　　機器電圧検出器
５０，１００　　過電圧保護回路
８０　　　　　　直流電源部（ＤＣ電源、コンバータ回路）
９０　　　　　　商用電源（ＡＣ電源）
９５　　　　　　インバータ（インバータ回路）
１２０，１７０　可変インピーダンス回路
１２１，１７１　低インピーダンス要素
１２２，１７２　高インピーダンス要素
１５０，２００　過電圧保護回路
３００　　　　　電力変換装置 11, 61 Switch 12, 62 Second switch 20, 70 Impedance circuit 33, 83 Voltage detector 35, 85 Bypass circuit 37 Device voltage detector 50, 100 Overvoltage protection circuit 80 DC power supply (DC power supply, converter circuit)
90 Commercial power (AC power)
95 Inverter (Inverter circuit)
120, 170 Variable impedance circuit 121, 171 Low impedance element 122, 172 High impedance element 150, 200 Overvoltage protection circuit 300 Power converter
特開２００９－２０７３２９号公報JP 2009-207329 A

Claims (14)

  1. 　電源と前記電源から電力を供給される機器との間に接続される過電圧保護回路であって、
    　前記電源と前記機器とを結ぶ電源ライン上に前記機器と直列に接続されるインピーダンス回路（２０，７０）と、
    　前記電源の電圧を検出する電圧検出器（３３，８３）と、
    　前記インピーダンス回路（２０，７０）を迂回するバイパス回路（３５，８５）と、
    を備え、
    　前記バイパス回路（３５，８５）は、前記バイパス回路（３５，８５）を開閉するスイッチ（１１，６１）を有し、
    　前記スイッチ（１１，６１）は、通常時は前記バイパス回路（３５，８５）を閉じ、前記電圧検出器（３３，８３）による検出値が所定の閾値を超えたときに前記バイパス回路（３５，８５）を遮断する、
    過電圧保護回路（５０，１００）。     An overvoltage protection circuit connected between a power source and a device supplied with power from the power source,
    An impedance circuit (20, 70) connected in series with the device on a power line connecting the power source and the device;
    A voltage detector (33, 83) for detecting the voltage of the power source;
    A bypass circuit (35, 85) bypassing the impedance circuit (20, 70);
    With
    The bypass circuit (35, 85) has a switch (11, 61) for opening and closing the bypass circuit (35, 85),
    The switch (11, 61) normally closes the bypass circuit (35, 85), and when the detection value by the voltage detector (33, 83) exceeds a predetermined threshold, the bypass circuit (35, 85). 85),
    Overvoltage protection circuit (50, 100).
  2. 　前記電源ラインを開閉する第２スイッチ（１２，６２）をさらに備え、
    　前記第２スイッチ（１２，６２）は、通常時は前記電源ラインを導通状態にし、前記電圧検出器（３３，８３）による検出値が所定の第２閾値を超えたとき、前記スイッチ（１１，６１）の動作後に前記電源ラインを遮断する、
    請求項１に記載の過電圧保護回路（５０，１００）。     A second switch (12, 62) for opening and closing the power line;
    The second switch (12, 62) normally turns on the power line, and when the detection value by the voltage detector (33, 83) exceeds a predetermined second threshold, the switch (11, 62) 61) shut off the power line after the operation of
    The overvoltage protection circuit (50, 100) according to claim 1.
  3. 　前記電源ラインを開閉する第２スイッチ（１２，６２）をさらに備え、
    　前記第２スイッチ（１２，６２）は、通常時は前記電源ラインを導通状態にし、前記電圧検出器（３３，８３）による検出値が所定の閾値を超えている時間が、所定の継続時間判定値よりも長くなったとき、前記スイッチ（１１，６１）の動作後に前記電源ラインを遮断する、
    請求項１に記載の過電圧保護回路（５０，１００）。     A second switch (12, 62) for opening and closing the power line;
    The second switch (12, 62) normally makes the power line conductive, and the time during which the detected value by the voltage detector (33, 83) exceeds a predetermined threshold is determined as a predetermined duration. When the value becomes longer than the value, the power line is shut off after the operation of the switch (11, 61).
    The overvoltage protection circuit (50, 100) according to claim 1.
  4. 　前記電源ラインを開閉する第２スイッチ（１２，６２）と、前記機器に印加される電圧を検出する機器電圧検出器（３７）をさらに備え、
    　前記第２スイッチ（１２，６２）は、通常時は前記電源ラインを導通状態にし、前記機器電圧検出器（３７）による検出値が所定の第３閾値を超えたとき、前記スイッチ（１１，６１）の動作後に前記電源ラインを遮断する、
    請求項１に記載の過電圧保護回路（５０，１００）。     A second switch (12, 62) for opening and closing the power line, and a device voltage detector (37) for detecting a voltage applied to the device,
    The second switch (12, 62) normally turns on the power line, and when the value detected by the device voltage detector (37) exceeds a predetermined third threshold, the switch (11, 61). ) Cut off the power line after operation
    The overvoltage protection circuit (50, 100) according to claim 1.
  5. 　電源と前記電源から電力を供給される機器との間に接続される過電圧保護回路であって、
    　前記電源と前記機器とを結ぶ電源ライン上に前記機器と直列に接続される可変インピーダンス回路（１２０，１７０）と、
    　前記電源の電圧を検出する電圧検出器（３３，８３）と、
    を備え、
    　前記可変インピーダンス回路（１２０，１７０）は、前記電圧検出器（３３，８３）による検出値が所定の閾値を超えたとき、インピーダンス値を通常時の値よりも大きくする、
    過電圧保護回路（１５０，２００）。     An overvoltage protection circuit connected between a power source and a device supplied with power from the power source,
    A variable impedance circuit (120, 170) connected in series with the device on a power line connecting the power source and the device;
    A voltage detector (33, 83) for detecting the voltage of the power source;
    With
    The variable impedance circuit (120, 170) makes the impedance value larger than a normal value when a detection value by the voltage detector (33, 83) exceeds a predetermined threshold.
    Overvoltage protection circuit (150, 200).
  6. 　前記可変インピーダンス回路（１２０，１７０）は、前記インピーダンス値を前記電圧検出器（３３，８３）による検出値の変化に応じて連続的に変化させる、
    請求項５に記載の過電圧保護回路（１５０，２００）。     The variable impedance circuit (120, 170) continuously changes the impedance value according to a change in the detection value by the voltage detector (33, 83).
    The overvoltage protection circuit (150, 200) according to claim 5.
  7. 　前記可変インピーダンス回路（１２０，１７０）は、前記インピーダンス値を前記電圧検出器（３３，８３）による検出値の変化に応じて段階的に変化させる、
    請求項５に記載の過電圧保護回路（１５０，２００）。     The variable impedance circuit (120, 170) changes the impedance value stepwise in accordance with a change in the detection value by the voltage detector (33, 83).
    The overvoltage protection circuit (150, 200) according to claim 5.
  8. 　前記可変インピーダンス回路（１２０，１７０）は、複数のインピーダンス要素を選択的に使用し、
    　複数の前記インピーダンス要素は、
    　第１インピーダンス値を有する第１インピーダンス要素（１２１，１７１）と、
    　前記第１インピーダンス値よりも大きい第２インピーダンス値を有する第２インピーダンス要素（１２２，１７２）と、
    を含み、
    　前記可変インピーダンス回路（１２０，１７０）は、前記第１インピーダンス要素（１２１，１７１）の使用時に前記電圧検出器（３３，８３）による検出値が所定の閾値を超えたとき、使用する前記インピーダンス要素を前記第１インピーダンス要素（１２１，１７１）から前記第２インピーダンス要素（１２２，１７２）へ切り換える、
    請求項５に記載の過電圧保護回路（１５０，２００）。     The variable impedance circuit (120, 170) selectively uses a plurality of impedance elements,
    The plurality of impedance elements are:
    A first impedance element (121, 171) having a first impedance value;
    A second impedance element (122, 172) having a second impedance value greater than the first impedance value;
    Including
    The variable impedance circuit (120, 170) is used when the detected value by the voltage detector (33, 83) exceeds a predetermined threshold value when the first impedance element (121, 171) is used. From the first impedance element (121, 171) to the second impedance element (122, 172),
    The overvoltage protection circuit (150, 200) according to claim 5.
  9. 　前記電源ラインを開閉する第２スイッチ（１２，６２）をさらに備え、
    　前記第２スイッチ（１２，６２）は、通常時は前記電源ラインを導通状態にし、前記電圧検出器（３３，８３）による検出値が所定の第２閾値を超えたとき、前記電源ラインを遮断する、
    請求項５から請求項８のいずれか１項に記載の過電圧保護回路（１５０，２００）。     A second switch (12, 62) for opening and closing the power line;
    The second switch (12, 62) normally turns on the power line, and shuts off the power line when a value detected by the voltage detector (33, 83) exceeds a predetermined second threshold. To
    The overvoltage protection circuit (150, 200) according to any one of claims 5 to 8.
  10. 　前記電源ラインを開閉する第２スイッチ（１２，６２）をさらに備え、
    　前記第２スイッチ（１２，６２）は、通常時は前記電源ラインを導通状態にし、前記電圧検出器（３３，８３）による検出値が所定の閾値を超えている時間が、所定の継続時間判定値よりも長くなったとき、前記電源ラインを遮断する、
    請求項５から請求項８のいずれか１項に記載の過電圧保護回路（１５０，２００）。     A second switch (12, 62) for opening and closing the power line;
    The second switch (12, 62) normally makes the power line conductive, and the time during which the detected value by the voltage detector (33, 83) exceeds a predetermined threshold is determined as a predetermined duration. Shut off the power line when longer than the value,
    The overvoltage protection circuit (150, 200) according to any one of claims 5 to 8.
  11. 　前記電源ラインを開閉する第２スイッチ（１２，６２）と、
    　前記機器に印加される電圧を検出する機器電圧検出器（３７）と、
    をさらに備え、
    　前記第２スイッチ（１２，６２）は、通常時は前記電源ラインを導通状態にし、前記機器電圧検出器（３７）による検出値が所定の第３閾値を超えたとき、前記電源ラインを遮断する、
    請求項５から請求項８のいずれか１項に記載の過電圧保護回路（１５０，２００）。     A second switch (12, 62) for opening and closing the power line;
    A device voltage detector (37) for detecting a voltage applied to the device;
    Further comprising
    The second switch (12, 62) normally turns on the power line, and shuts off the power line when a value detected by the device voltage detector (37) exceeds a predetermined third threshold. ,
    The overvoltage protection circuit (150, 200) according to any one of claims 5 to 8.
  12. 　前記電源は、ＡＣ電源である、
    請求項１から請求項１１のいずれか１項に記載の過電圧保護回路（５０，１５０）。     The power source is an AC power source;
    The overvoltage protection circuit (50, 150) according to any one of claims 1 to 11.
  13. 　前記電源は、ＤＣ電源である、
    請求項１から請求項１１のいずれか１項に記載の過電圧保護回路（１００，２００）。     The power source is a DC power source;
    The overvoltage protection circuit (100, 200) according to any one of claims 1 to 11.
  14. 　交流電源に接続され、交流電圧を直流電圧に変換するコンバータ回路（８０）と、
    　前記直流電圧を交流電圧に変換するインバータ回路（９５）と、
    　請求項１から請求項１３のいずれか１項に記載の過電圧保護回路と、
    を備える、
    電力変換装置。     A converter circuit (80) connected to an AC power source and converting AC voltage to DC voltage;
    An inverter circuit (95) for converting the DC voltage into an AC voltage;
    The overvoltage protection circuit according to any one of claims 1 to 13,
    Comprising
    Power conversion device.
PCT/JP2014/084101 2013-12-27 2014-12-24 Overvoltage protection circuit and power conversion device provided therewith WO2015098937A1 (en)

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