JP2011061949A - Instantaneous voltage drop protective device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress wasteful power consumption and reduce the size of a radiation fin, and the like, to reduce a device cost by reducing the power loss in a semiconductor switch 13. <P>SOLUTION: An output conversion transformer 15 is placed between the semiconductor switch 13, provided in a power supply line 12 supplied with an alternating-current power from an alternating-current power supply 2 and an output end 11, and the output conversion transformer is so configured that the winding number ratio of the primary winding 151 to the secondary winding 152 is equal to the ratio of the rated input voltage to rated output voltage; and the winding number of the intermediate tap 153 of the primary winding 151 is equal to the winding number of the secondary winding 152. As a result, an input voltage Vin can be made higher than an output voltage Vout (for example, Vin=200 V, Vout=100 V). By setting the input voltage Vin higher, the load current is reduced as compared with the case where the input voltage Vin and the output voltage Vout are identical to each other, power loss at the semiconductor switch 13 is reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an instantaneous voltage drop protection device that supplies AC power to a load instead when the voltage of AC power supplied from an AC power supply to the load temporarily decreases or when a power failure occurs temporarily. .

  Conventionally, when the voltage of the AC power supplied from the commercial AC power source to the load drops for a short time or when it is interrupted for a short time, an instantaneous voltage drop protection device for supplying AC power to the load instead is provided. Widely used. FIG. 3 is a schematic block diagram of a conventional instantaneous voltage drop protection device (see, for example, Patent Documents 1 and 2).

  The input terminal 10 of the instantaneous voltage drop protection device 100 is connected to an AC power supply source, for example, an AC power supply 2 having a voltage of 100 V or 200 V, and the output terminal 11 is connected to a load 3 that is an AC power supply destination. Is done. The power supply line 12 between the input terminal 10 and the output terminal 11 is provided with a semiconductor switch 13 such as an IGBT. When the semiconductor switch 13 is turned off, the input terminal 10 and the output terminal 11 are disconnected. A voltage compensation unit 14 is connected to the power supply line 12 between the semiconductor switch 13 and the output terminal 11.

  The voltage compensator 14 charges the electrolytic capacitor 144 by converting the AC power into direct current by holding the electrical energy to be supplied at the time of instantaneous voltage drop or instantaneous power interruption, or conversely, the electrolytic capacitor 144. An inverter unit 145 for converting the electric energy held in the inverter into DC / AC, a filter 146 for removing high-frequency components superimposed on AC power, a transformer 141 for charging the electrolytic capacitor 144, a rectifier unit 142, and a switch. A supplementary charging unit composed of 143 or the like is provided.

  The basic operation of the instantaneous voltage drop protection device 100 is as follows. When AC power is normally supplied from the AC power supply 2, the semiconductor switch 13 is in an on state, and AC power from the AC power supply 2 is supplied to the load 3 through the power supply line 12. At this time, the electrolytic capacitor 144 is kept charged to its rated voltage. That is, when the charging voltage of the electrolytic capacitor 144 decreases to some extent from the rated voltage due to natural discharge, the auxiliary charging unit operates by charging the switch 143 to charge the electrolytic capacitor 144. Further, as will be described later, when the AC voltage is restored after the voltage of the electrolytic capacitor 144 is greatly reduced due to an instantaneous power failure, the inverter unit 145 converts the AC voltage supplied through the power supply line 12 to AC / DC conversion. Is driven, so that the electrolytic capacitor 144 is rapidly charged.

  When the AC voltage supplied from the AC power supply 2 temporarily decreases due to an instantaneous power failure or the like, the semiconductor switch 13 is turned off and the inverter unit 145 converts the electric energy stored in the electrolytic capacitor 144 to DC / AC conversion. Can be switched. Thereby, the AC power source 2 is disconnected from the load 3, and the AC power supplied from the inverter unit 145 is supplied to the load 3 through the output terminal 11. When the AC voltage supplied from the AC power supply 2 is restored, the semiconductor switch 13 is turned on, and the operation of the inverter unit 145 is switched to charge the electrolytic capacitor 144 as described above.

  In the conventional instantaneous voltage drop protection device 100 described above, the voltage input to the input terminal 10 (that is, the rated input AC voltage) and the voltage output from the output terminal 11 (rated output AC voltage) must be the same. In the case of a device with a rated output AC voltage of 100V, the rated input AC voltage is also 100V. In factories and the like where such instantaneous voltage drop protection devices are frequently used, the rated input AC voltage of devices serving as loads varies, such as 100V, 200V, and 400V. Therefore, in order to cope with such various loads, instantaneous voltage drop protection devices having different specifications such as input / output AC voltages of 100V, 200V, 400V and the like are used.

  In the above instantaneous voltage drop protection device, the semiconductor switch 13 provided on the power supply line 12 has an on-resistance. Therefore, when a load current flows with the semiconductor switch 13 turned on, a voltage drop occurs in the semiconductor switch 13. And power loss occurs. When the output power capacity is the same, the lower the voltage on the power supply line 12 is, the more load current flows through the line 12, so that the power loss in the semiconductor switch 13 increases. As described above, in the instantaneous voltage drop protection device 100, the input / output AC voltage is the same, and therefore, when the input / output AC voltage is 100V, the semiconductor switch 13 is compared with the case where the input / output AC voltage is 200V. The power loss is about double. A large power loss not only leads to an increase in power consumption, but also increases the cost of the apparatus, such as providing a large radiating fin in order to improve the heat dissipation in the semiconductor switch 13.

JP 2008-54468 A JP 2009-112128 A

  The present invention has been made in view of the above-mentioned problems, and its object is to suppress power loss in a semiconductor switch provided on a power supply line, thereby suppressing device cost and power consumption. An object of the present invention is to provide an instantaneous voltage drop protection device capable of

The present invention made to solve the above problems is provided in a power supply line between an input end to which AC power from an AC power supply is supplied and an output end to supply power to a load, and opens and closes the line. A switch, power storage means for storing electrical energy, and AC power supplied from an AC power source are AC / DC converted to charge the power storage means, while being stored in the power storage means when an instantaneous voltage drop occurs. A voltage compensation means including a power conversion means for converting electric energy into DC / AC; and opening the switch when the AC voltage from the AC power supply drops, and using the electric energy stored in the power storage means. And a control means for operating the power conversion means to supply alternating current power, and an instantaneous voltage drop protection device comprising:
An output conversion transformer is inserted in the power supply line between the switch and the output end so that a primary winding is connected to the switch side and a secondary winding is connected to the output end side, respectively. The voltage compensating means is connected to an intermediate tap provided in the middle of the primary winding of the output conversion transformer.

  As one aspect of the instantaneous voltage drop protection device according to the present invention, when the AC voltage applied to the input terminal is Vin and the AC voltage output from the output terminal is Vout (where Vout <Vin), the output conversion The ratio of the number of turns of the primary winding and the secondary winding of the transformer is n1: n2 = Vin: Vout, the number of turns at the intermediate tap of the primary winding is the same as the number of turns of the secondary winding, and It is preferable that the output AC voltage of the voltage compensation means when the instantaneous voltage drop occurs is Vout. For example, if Vin = 200 [V] and Vout = 100 [V], the winding number ratio of the primary winding and the secondary winding is n1: n2 = 2: 1, and the output of the voltage compensation means The AC voltage is 100 [V].

  In the instantaneous voltage drop protection device according to the present invention, the switch is closed when a normal AC voltage is applied to the input terminal, and according to the turns ratio of the primary winding and the secondary winding of the output conversion transformer. The stepped-down AC voltage is output from the output terminal. That is, according to the configuration of the above aspect, the AC voltage output from the output terminal is Vout, but the AC voltage on the power supply line between the input terminal and the output conversion transformer is Vin higher than Vout. Therefore, the load current flowing through the switch is Vout / Vin times as compared with the case where there is no output conversion transformer and the AC voltage applied to the input terminal is equal to Vout. That is, if Vin = 200 [V] and Vout = 100 [V], the load current is halved. As the load current decreases in this way, the power loss in the switch decreases.

  When the AC voltage Vin is applied to the primary winding of the output conversion transformer, a divided voltage corresponding to the number of windings appears in the intermediate tap, and this divided voltage is supplied to the voltage compensating means to the electric storage means. Is accumulated. That is, the voltage compensation means operates at a voltage lower than the AC voltage applied to the input terminal. When the AC voltage applied to the input terminal drops due to an instantaneous power failure, etc., the switch is opened by the control means, and the power conversion means operates to supply AC power using the electrical energy stored in the power storage means Then, the AC voltage generated by the voltage compensation means is applied to the intermediate tap of the primary winding of the output conversion transformer. Since a voltage corresponding to the winding ratio between the intermediate tap and the secondary winding is generated on the secondary winding side, for example, if the number of windings is equal as described above, the AC generated by the voltage compensation means A voltage is output from the output terminal.

  As long as the number of windings is as described above, the voltage compensation means may be configured to operate with an AC voltage output from the output end, and even if the AC voltage applied to the input end is large, the voltage compensation means The withstand voltage of the circuit elements constituting the circuit can be low. For this reason, it is possible to avoid the voltage compensation means from becoming a cost increase factor.

  In addition, as a configuration for driving a load that requires a higher input AC voltage, a plurality of instantaneous voltage drop protection devices according to the present invention are used, and the input terminals of the plurality of instantaneous voltage drop protection devices are AC connected in common. It is good also as a structure which connects to a power supply, connects the secondary winding of the output conversion transformer of each instantaneous voltage drop protection device in series, and made the both ends into the output terminal. According to this configuration, by using a plurality of instantaneous voltage drop protection devices having the same configuration, an AC voltage that is an integral multiple of the output AC voltage of one instantaneous voltage drop protection device can be easily obtained.

  According to the instantaneous voltage drop protection device of the present invention, the input AC voltage applied to the input terminal can be increased regardless of the output AC voltage output from the output terminal, so that the IGBT provided in the power supply line The power loss in the switch can be suppressed as compared with the conventional device, and the effect of reducing the power loss can be enhanced as the input AC voltage is increased. As a result, the energy supplied to the input terminal is less likely to be consumed unnecessarily, and the power consumption can be reduced. Further, since the amount of heat generated by the switch is reduced, the heat radiating portion such as the heat radiating fin can be reduced in size, and the device cost can be reduced. Furthermore, even if the input AC voltage applied to the input terminal is increased, there is no need to make the circuit configuration of the voltage compensation means correspond to the voltage rise, so there is no increase in the cost of the voltage compensation means. Can be suppressed.

1 is a schematic block diagram of an embodiment of an instantaneous voltage drop protection device according to the present invention. The schematic block block diagram of the other Example of the instantaneous voltage drop protection apparatus which concerns on this invention. The schematic block block diagram of one Example of the conventional instantaneous voltage drop protection apparatus.

[First embodiment]
An embodiment (first embodiment) of an instantaneous voltage drop protection device according to the present invention will be described. FIG. 1 is a schematic block diagram of an instantaneous voltage drop protection device 1 according to this embodiment. This instantaneous voltage drop protection device 1 has a specification that the output AC voltage is single-phase 100V and the input AC voltage is single-phase 200V.
In the instantaneous voltage drop protection device 1 shown in FIG. 1, the same components as those in the conventional instantaneous voltage drop protection device 100 shown in FIG.

  In the instantaneous voltage drop protection device 1, an output conversion transformer 15 is inserted between the semiconductor switch 13 provided on the power supply line 12 and the output terminal 11, and the power supply line 12 is connected via the output conversion transformer 15. The voltage compensation unit 14 is also connected. In the output conversion transformer 15, the winding ratio between the primary winding 151 and the secondary winding 152 is 2: 1, and the primary winding 151 is located at an intermediate position, that is, the number of windings with respect to the secondary winding 152. An intermediate tap 153 is provided at a position where the ratio is 1: 1. The power supply line 12 is connected to both ends of the primary winding 151 of the output conversion transformer 15, and the voltage compensator 14 is connected between the intermediate tap 153 of the output conversion transformer 15 and the power supply line 12 on the negative polarity side. .

  The voltage of the AC power supplied to the input terminal 10 is detected by the voltage drop detection unit 16, and the control unit 17 mainly composed of the CPU performs an on / off operation of the semiconductor switch 13, an inverter according to a preset control program. The operation of the unit 145 and the on / off operation of the switch 143 are controlled.

Next, the operation of the instantaneous voltage drop protection device 1 will be described.
When AC power having an AC voltage of 200 V is normally applied from the AC power supply 2 to the input terminal 10, the control unit 17 keeps the semiconductor switch 13 in the ON state. As a result, an AC voltage of 200 V applied to the input terminal 10 is applied to the primary winding 151 of the output conversion transformer 15, and an AC voltage of 100 V is generated in the secondary winding 152 in accordance with the winding ratio. To do. This 100 V AC voltage is output from the output terminal 11 and applied to the load 3.

  In a state where an AC voltage of 200 V is applied to the primary winding 151 of the output conversion transformer 15, an AC voltage of 100 V appears at the intermediate tap 153, and this is applied to the voltage compensator 14. The voltage compensator 14 operates in the same manner as in the conventional example, and when the charging voltage of the electrolytic capacitor 144 greatly falls below the rated voltage due to an instantaneous power failure or the like, the controller 17 supplies the voltage via the intermediate tap 153 of the output conversion transformer 15. The operation of each switching element of the inverter unit 145 is controlled such that the AC power to be converted is AC / DC converted, whereby the charging voltage of the electrolytic capacitor 144 is rapidly recovered. When the charging voltage of the electrolytic capacitor 144 is slightly lower than the rated voltage due to natural discharge, the electrolytic capacitor 144 is charged by turning on the switch 143 and operating the auxiliary charging unit. Thereby, when electric power is normally supplied from AC power supply 2, the charging voltage of electrolytic capacitor 144 is maintained in the vicinity of the rated voltage.

  For example, when the AC voltage applied to the input terminal 10 decreases due to a short time power failure or the like, the control unit 17 recognizes the voltage decrease based on the detection signal from the voltage decrease detection unit 16. Then, the control unit 17 turns off the semiconductor switch 13, disconnects the output conversion transformer 15 and the input terminal 10, and switches the inverter unit 145 so as to convert the electric energy accumulated in the electrolytic capacitor 144 into DC / AC conversion. Switches the operation of the element. As a result, an AC voltage of 100 V based on the electric energy accumulated in the electrolytic capacitor 144 is applied to the intermediate tap 153 of the output conversion transformer 15 via the filter 146.

  At this time, since the semiconductor switch 13 is in the OFF state, it can be considered that only the winding between the intermediate tap 153 and the negative polarity side power supply line 12 exists in the primary winding 151 of the output conversion transformer 15. Accordingly, the output conversion transformer 15 can be regarded as having the same number ratio of the primary winding and the secondary winding, and the secondary winding 152 has the same 100 V AC voltage as that applied to the primary winding 151. Is born. As a result, even when the AC voltage from the AC power supply 2 decreases, an AC voltage of 100 V continues to be applied from the output end 11 to the load 3.

  When the AC voltage from the AC power supply 2 is restored, the control unit 17 recognizes this by the detection signal from the voltage drop detection unit 16, turns on the semiconductor switch 13, and switches the inverter unit 145 to AC / DC conversion operation. Then, the electrolytic capacitor 144 is charged to recover the charging voltage. As described above, in the instantaneous voltage drop protection device 1 according to the present embodiment, while the AC voltage of 200 V is applied to the input terminal 10, the AC voltage of 100 V is output from the output terminal 11 to the load 3, and the inverter unit 145. The voltage compensator 14 including the circuit performs an operation based on an AC voltage of 100 V as in the conventional case.

The power loss in the semiconductor switch 13 is compared between the instantaneous voltage drop protection device 1 of the first embodiment described above and the conventional instantaneous voltage drop protection device 100 described with reference to FIG.
Now, in the instantaneous voltage drop protection device 1 shown in FIG. 1, it is assumed that the AC power supply 2 is single-phase 200V, the AC voltage output from the output terminal 11 is 100V, and the output capacity is 200 kVA. In this case, when the semiconductor switch 13 is in the ON state, the current flowing through the power supply line 12 is 1000 A, and if the voltage drop at the semiconductor switch 13 is 2 V, the power loss at the semiconductor switch 13 is 2 [V ] × 1000 [A] = 2 [kW]. On the other hand, since the conventional instantaneous voltage drop protection device 100 uses the single-phase 100V AC power supply 2 to output the AC voltage 100V from the output end 11, the voltage of the power supply line 12 is also 100V. At this time, if the output capacity is 200 kVA, the current flowing in the power supply line 12 is 2000 A. If the voltage drop in the semiconductor switch 13 is 2 V, the power loss in the semiconductor switch 13 is 2 [V] × 2000. [A] = 4 [kW].

  As described above, in the instantaneous voltage drop protection device of the first embodiment, even when the same AC power as that in the past is supplied from the output terminal 11, the voltage of the AC power input to the input terminal 10 is increased by a factor of two. The power loss in the semiconductor switch 13 can be suppressed to ½. Furthermore, if the voltage of the AC power input to the input terminal 10 is increased by a factor of 4, the power loss at the semiconductor switch 13 can be suppressed to ¼.

  When the AC voltage output from the output terminal 11 is the same and the AC voltage input to the input terminal 10 is different, the primary winding 151 and the secondary winding 152 of the output conversion transformer 15 are changed according to the voltage. The winding ratio and the winding tap ratio of the intermediate tap 153 and the primary winding 151 may be adjusted as appropriate, and the circuit configuration of the voltage compensator 14 need not be changed. Therefore, most of the circuit configurations can be made common to correspond to different rated input AC voltages.

[Second Embodiment]
FIG. 2 shows an embodiment (second embodiment) of the instantaneous voltage drop protection device in which the rated output AC voltage is increased by using a plurality (three in this example) of instantaneous voltage drop protection devices having the configuration of the first embodiment. It is a block block diagram which shows. In FIG. 2, 1A, 1B, and 1C are parts of the instantaneous voltage drop protection device 1 shown in FIG. 1 excluding the output conversion transformer 15, and 15a, 15b, and 15c correspond to the output conversion transformer 15. Part. The input terminals 10 of the plurality of instantaneous voltage drop protection devices 1A, 1B, and 1C are shared, and an AC voltage is applied in parallel from the AC power supply 2 to each of the instantaneous voltage drop protection devices 1A, 1B, and 1C. On the other hand, the secondary windings of the output conversion transformers 15a, 15b, 15c of the instantaneous voltage drop protection devices 1A, 1B, 1C are connected in series, and both ends thereof are connected to the output terminal 11.

  Since each of the instantaneous voltage drop protection devices 1A, 1B, 1C has the same configuration as the above-described instantaneous voltage drop protection device 1 of the first embodiment and operates in the same manner, AC power is normally supplied from the AC power source 2. 100V AC voltage appears in the secondary windings of the output conversion transformers 15a, 15b, and 15c both when the input AC voltage is temporarily reduced due to a momentary power failure or the like. Therefore, an AC voltage of 300 V obtained by adding these three systems of AC voltages can be applied to the load 3 from the output terminal 11.

  In the first embodiment, the case where the rated input AC voltage of the instantaneous voltage drop protection device 1 is 200 V and the rated output AC voltage is 100 V has been described. However, the rated input AC voltage is higher than the rated output AC voltage. It can be arbitrarily selected under the condition. For example, it is obvious that the rated input AC voltage can be 400V and the rated output AC voltage can be 100V, or the rated input AC voltage can be 400V and the rated output AC voltage can be 200V. In addition, as for other points, it is a matter of course that modifications, corrections, and additions are appropriately included in the scope of the claims of the present application within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C ... Instantaneous voltage drop protection device 10 ... Input end 11 ... Output end 12 ... Power supply line 13 ... Semiconductor switch 14 ... Voltage compensation part 141 ... Transformer 142 ... Rectification part 143 ... Switch 144 ... Electrolytic capacitor 145 ... Inverter unit 146 ... Filters 15, 15a, 15b, 15c ... Output conversion transformer 151 ... Primary winding 152 ... Secondary winding 153 ... Intermediate tap 16 ... Voltage drop detection unit 17 ... Control unit

Claims (3)

A switch provided on a power supply line between an input end supplied with AC power from an AC power source and an output end supplying power to the load; a storage means for storing electrical energy; and A voltage including power conversion means for AC / DC conversion of AC power supplied from an AC power source to charge the power storage means, while DC / AC conversion is performed on electrical energy stored in the power storage means when an instantaneous voltage drop occurs. Compensation means and when the AC voltage from the AC power supply drops, the switch is opened, and the power conversion means is operated so as to supply AC power using electric energy stored in the power storage means And an instantaneous voltage drop protection device comprising:
An output conversion transformer is inserted in the power supply line between the switch and the output end so that a primary winding is connected to the switch side and a secondary winding is connected to the output end side, respectively. An instantaneous voltage drop protection device, wherein the voltage compensating means is connected to an intermediate tap provided in the middle of the primary winding of the output conversion transformer. The instantaneous voltage drop protection device according to claim 1,
When the AC voltage applied to the input terminal is Vin and the AC voltage output from the output terminal is Vout, the turns ratio of the primary winding and the secondary winding of the output conversion transformer is expressed as n1: n2 = Vin: Vout, the number of windings at the intermediate tap of the primary winding is the same as the number of windings of the secondary winding, and the output AC voltage of the voltage compensation means when the instantaneous voltage drop occurs is Vout. Features an instantaneous voltage drop protection device.   A plurality of the instantaneous voltage drop protection devices according to claim 1 or 2 are used, and the input terminals of the plurality of instantaneous voltage drop protection devices are connected to an AC power source in common, and the secondary of the output conversion transformer of each instantaneous voltage drop protection device An instantaneous voltage drop protection device characterized in that windings are connected in series and both ends are used as output ends.

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