WO2015159760A1 - Power conversion device - Google Patents

Power conversion device Download PDF

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Publication number
WO2015159760A1
WO2015159760A1 PCT/JP2015/060852 JP2015060852W WO2015159760A1 WO 2015159760 A1 WO2015159760 A1 WO 2015159760A1 JP 2015060852 W JP2015060852 W JP 2015060852W WO 2015159760 A1 WO2015159760 A1 WO 2015159760A1
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WIPO (PCT)
Prior art keywords
voltage
smoothing capacitor
relay
value
set value
Prior art date
Application number
PCT/JP2015/060852
Other languages
French (fr)
Japanese (ja)
Inventor
治信 温品
洋平 久保田
圭一 石田
慧 小川
Original Assignee
東芝キヤリア株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 東芝キヤリア株式会社 filed Critical 東芝キヤリア株式会社
Priority to CN201580003687.7A priority Critical patent/CN105874702B/en
Priority to JP2016513728A priority patent/JP6255088B2/en
Publication of WO2015159760A1 publication Critical patent/WO2015159760A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode

Definitions

  • Embodiment of this invention is related with the power converter device which converts the voltage of AC power supply into DC, and converts the DC voltage into the AC voltage of a predetermined frequency.
  • a rectifier circuit that converts the voltage of the commercial AC power source into DC, a smoothing capacitor that smoothes the output voltage of the rectifier circuit, an inverter that converts the voltage of the smoothing capacitor into an AC voltage of a predetermined frequency, a commercial AC power source and a rectifier circuit,
  • a power conversion device in which a PTC thermistor for preventing an inrush current (a resistor whose resistance increases with a rise in temperature) is inserted and connected to a power line between and a relay contact is connected in parallel to the PTC thermistor.
  • This power converter prevents inrush current when the power is turned on by opening the relay contact and putting the PTC thermistor into the current path.
  • the relay contact is closed to form a short circuit to the PTC thermistor, and the PTC thermistor is disconnected. Even when the voltage of the commercial AC power supply temporarily decreases and the voltage of the smoothing capacitor falls below the output voltage of the rectifier circuit, the relay contact is opened and a PTC thermistor is turned on to prevent inrush current.
  • a relay is used to turn on and off the PTC thermistor.
  • the relay changes an electrical signal into a mechanical contact movement, there is a delay of several milliseconds from when the electrical signal is received until the contact is actually opened and closed. This time delay may prevent the inrush current from being prevented.
  • An object of an embodiment of the present invention is to provide a power conversion device that can reliably prevent an inrush current.
  • the power conversion device is a converter that converts a voltage of a commercial AC power source into a DC voltage, a smoothing capacitor connected to an output terminal of the converter, a voltage of the smoothing capacitor is converted into an AC voltage, and the AC voltage Output as drive power to the load, a resistor for preventing inrush current disposed in a current path between the converter and the smoothing capacitor, and a relay having a contact connected in parallel to the resistor, Control means for closing the relay when the voltage of the smoothing capacitor rises above a specified value, and opening the relay when the voltage of the smoothing capacitor drops below a set value.
  • the set value is higher than the minimum voltage value of the smoothing capacitor necessary for the current flowing through the converter not to exceed the maximum allowable current of the converter.
  • FIG. 1 is a block diagram showing the configuration of each embodiment.
  • FIG. 2 is a flowchart showing the control of the first embodiment.
  • FIG. 3 is a time chart showing the voltage change of the smoothing capacitor, the change of the relay drive signal, and the change of the normally open contact in the first embodiment.
  • FIG. 4 is a flowchart showing the control of the second embodiment.
  • FIG. 5 is a time chart showing a voltage change of a smoothing capacitor, a change of a relay drive signal, and a change of a normally open contact in the second embodiment.
  • FIG. 6 is a flowchart showing the control of the third embodiment.
  • FIG. 7 is a time chart showing the voltage change of the smoothing capacitor, the change of the relay drive signal, and the change of the normally open contact in the third embodiment.
  • FIG. 8 is a flowchart showing the control of the fourth embodiment.
  • a converter 2 is connected to a commercial three-phase AC power source 1.
  • Converter 2 includes a plurality of switching elements and a plurality of diodes, and converts the AC voltage of commercial three-phase AC power supply 1 into a DC voltage.
  • a smoothing capacitor (electrolytic capacitor) 4 is connected to the output end of the converter 2 via a parallel circuit of the resistor 3 and the relay contact 30a.
  • the resistor 3 is, for example, a PTC thermistor for preventing inrush current.
  • the relay contact 30 a is a normally open contact of the relay 30.
  • an inverter 10 is connected to the smoothing capacitor 4, and a load, for example, a brushless DC motor (also referred to as a permanent magnet synchronous motor) M is connected to the output terminal of the inverter 10.
  • the inverter 10 includes a U-phase series circuit of two switching elements T1 and T2 each having a reflux diode connected in antiparallel, and a V-phase series circuit of two switching elements T3 and T4 each having a reflux diode connected in antiparallel, It includes a W-phase series circuit of two switching elements T5 and T6 each having a reverse diode connected in reverse parallel, converts the voltage of the smoothing capacitor 4 into an AC voltage of a predetermined frequency, and converts the AC voltage to the brushless DC motor M. Output as drive power. Phase windings Lu, Lv, and Lw of the brushless DC motor M are connected to interconnection points of both switching elements in each series circuit of the inverter 10, respectively.
  • the DC voltage Vd is applied to the relay 30 via the collector / emitter of the NPN transistor 22.
  • the base of the NPN transistor 22 is connected to the main controller 20.
  • the NPN transistor 22 is turned on when the relay drive signal D supplied from the main controller 20 is at a high level, and turned off when the relay drive signal D is at a low level.
  • the NPN transistor 22 is turned on, the exciting coil of the relay 30 is energized and the relay contact 30a is closed. That is, the relay 30 is closed.
  • the NPN transistor 22 is turned off, the exciting coil of the relay 30 is de-energized and the relay contact 30a is opened. That is, the relay 30 opens.
  • the voltage detector 21 is connected to both ends of the smoothing capacitor 4.
  • the voltage detector 21 detects the voltage Vdc generated in the smoothing capacitor 4. This voltage detector 21 is connected to the main controller 20.
  • Current sensors (current transformers) 11, 12, and 13 are disposed on each phase energization line between the output terminal of the inverter 10 and the brushless DC motor M.
  • Current sensors 11, 12, and 13 detect currents (phase currents) flowing through the phase windings Lu, Lv, and Lw of the brushless DC motor M, respectively. These current sensors 11, 12, and 13 are connected to the main control unit 20.
  • the sensorless vector controller 50 is further connected to the main controller 20.
  • the sensorless vector control unit 50 includes a current detection unit 51, a speed estimation calculation unit 52, an integration unit 53, a subtraction unit 54, a speed control unit 55, a calculation unit 56, subtraction units 57 and 58, a current control unit (first current control). Unit) 61, a current control unit (second current control unit) 62, and a PWM signal generation unit 63.
  • the current detection unit 51 performs three-phase to two-phase conversion on the detection currents of the current sensors 11, 12, and 13, and field axis (d axis) coordinates and torque axis (q axis) coordinates on the rotor axis in the brushless DC motor M.
  • d axis field axis
  • q axis torque axis
  • Iq torque component current
  • the speed estimation calculation unit 52 estimates the rotor speed ⁇ est of the brushless DC motor M by calculation based on the field component current Id and the torque component current Iq detected by the current detection unit 51.
  • brushless operation is performed by calculation using the field component current Id, the torque component current Iq, the field component voltage Vd obtained by the current control unit 61, and the torque component voltage Vq obtained by the current control unit 62.
  • a field component speed electromotive force (referred to as d-axis speed electromotive force) Ed in the DC motor M is estimated, and an estimated rotor speed ⁇ est is obtained based on a proportional / integral control (PI control) calculation of the d-axis speed electromotive force Ed.
  • PI control proportional / integral control
  • the integrating unit 53 obtains an estimated rotor position ⁇ est by integrating the estimated rotor speed ⁇ est obtained by the speed estimation calculating unit 52.
  • the estimated rotor position ⁇ est is supplied to the current detection unit 51 and the PWM signal generation unit 63.
  • the subtracting unit 54 obtains a speed deviation between the target speed ⁇ ref and the estimated rotor speed ⁇ est by subtracting the estimated rotor speed ⁇ est from the target speed ⁇ ref commanded from the main control unit 20.
  • the speed control unit 55 calculates a target value Iqref of the torque component current Iq by calculating a proportional / integral control (PI control) on the speed deviation obtained by the subtracting unit 54.
  • PI control proportional / integral control
  • the calculation unit 56 obtains the target value Idref of the field component current Id from the target value Iqref of the torque component current Iq.
  • the subtracting unit 57 obtains a deviation ⁇ Id between the target value Idref and the field component current Id by subtracting the field component current Id from the target value Idref.
  • the subtraction unit 58 obtains a deviation ⁇ Iq between the target value Iqref and the torque component current Iq by subtracting the torque component current Iq from the target value Iqref.
  • the current control unit 61 obtains the field component voltage Vd converted into the d-axis coordinate on the rotor shaft in the brushless DC motor M by the proportional / integral control (PI control) calculation of the deviation ⁇ Id.
  • the current control unit 62 obtains a torque component voltage Vq converted into q-axis coordinates on the rotor shaft in the brushless DC motor M by proportional / integral control (PI control) calculation of the deviation ⁇ Iq.
  • the PWM signal generation unit 63 generates a switching pulse width modulation signal (referred to as a PWM signal) for the inverter 10 according to the field component voltage Vd, the torque component voltage Vq, and the estimated rotor position ⁇ est.
  • the switching elements T1 to T6 of the inverter 10 are turned on and off, and drive voltages Vu, Vv, and Vw for the phase windings Lu, Lv, and Lw of the brushless DC motor M are output from the inverter 10.
  • the speed of the brushless DC motor M is controlled so as to reach the target speed in a short time.
  • the main control unit 20 has the following means (1) to (3) as main functions.
  • the first set value V1 ′ is a specified value V2 or less, and is a value that is higher by a predetermined value than the minimum voltage value V1 of the smoothing capacitor 4 that is necessary for the current flowing through the converter 2 not to exceed the allowable maximum current of the converter 2. It is.
  • the allowable maximum current of the converter 2 is, for example, the maximum rated current of a switching element or a diode in the converter 2.
  • the inrush current Ix (in accordance with the difference “Va ⁇ Vdc” between the output voltage Va of the converter 2 and the voltage Vdc of the smoothing capacitor 4 and the line impedance Z from the commercial three-phase AC power supply 1 to the smoothing capacitor 4. Va ⁇ Vdc) / Z tends to flow from the converter 2 to the smoothing capacitor 4.
  • the main control unit 20 determines the magnitude of the load based on the torque component current Iq in the sensorless vector control unit 50 (Step S1). S5). Specifically, when the torque component current Iq is less than a certain value, the main control unit 20 determines that the load is a light load with a value less than a predetermined value, and when the torque component current Iq is greater than or equal to a certain value. It is determined that the load is a medium load or a heavy load greater than or equal to a predetermined value.
  • the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the first set value V1 ′ (step S6) when determining that the load is a light load (YES in step S5).
  • the main control unit 20 sets the relay drive signal D to a low level to turn off the transistor 22,
  • the relay 30 is de-energized (opening operation) (step S7).
  • the relay contact 30a is opened, and the resistor 3 is put in the energization path between the converter 2 and the smoothing capacitor 4.
  • the relay contact 30a is a mechanical contact that moves mechanically, a time delay t1 of several milliseconds occurs after the relay drive signal D is set to a low level until the relay contact 30a is actually opened.
  • the first set value V1 ′ higher than the minimum voltage value V1 necessary for preventing the inrush current is selected for deactivating the relay 30, before the voltage Vdc drops below the minimum voltage value V1.
  • the relay contact 30a is opened and the resistor 3 is turned on. Therefore, even if the voltage Vdc falls below the minimum voltage value V1, since the resistor 3 is already turned on at that time, no inrush current occurs. That is, the semiconductor switch and the diode of the converter 2 can be prevented from being destroyed.
  • main controller 20 determines that voltage Vdc of smoothing capacitor 4 is decreasing (NO in step S1, YES in step S4), and determines that the load is medium load or heavy load (NO in step S5).
  • the main control unit 20 sets the relay drive signal D to a low level and turns off the transistor 22, thereby
  • the relay 30 is de-energized (step S7).
  • the relay 30 is de-energized, the relay contact 30a is opened, and the resistor 3 is put in the energization path between the converter 2 and the smoothing capacitor 4.
  • the load is a medium load or a heavy load
  • the voltage Vdc descends quickly, and a time delay t1 of several msec from when the relay drive signal D is set to a low level until the relay contact 30a is actually opened.
  • the relay contact 30a is opened before the voltage Vdc drops to the minimum voltage value V1, and the resistance is reduced.
  • Container 3 is turned on. That is, even when the voltage Vdc falls below the minimum voltage value V1, since the resistor 3 is already turned on at that time, no inrush current occurs. Therefore, destruction of the semiconductor switch and the diode of the converter 2 can be prevented.
  • the main control unit 20 stops switching of the inverter 10.
  • the relay 30 when the voltage Vdc drops, the relay 30 is de-energized at a timing when the voltage Vdc falls below the first set value V1 ′ or the second set value V2 that is higher than the minimum voltage value V1 for preventing inrush current. Even if there is a time delay in opening and closing the relay contact 30a, the inrush current can be reliably prevented.
  • the first set value V1 ′ is selected for de-energizing the relay 30 at light load
  • the voltage Vdc is applied during the switching time delay t2 of the relay contact 30a even if there is a sudden drop in the voltage Vdc at the time of heavy load. Is selected to a minimum value that does not reach the minimum voltage value V1 for preventing inrush current. Thereby, the introduction of the resistor 3 can be extended to the last timing of inrush current generation.
  • the resistor 3 When the resistor 3 is turned on, the input power (current) is limited. When this input power is less than the driveable power of the inverter 10, the inverter 10 cannot be driven. However, as described above, the insertion of the resistor 3 can be extended until the timing of the inrush current generation, so that the drive stop of the inverter 10 due to the limitation of the input power can be postponed as much as possible. As a result, the operation rate of the inverter 10 can be increased. In addition, when the resistor 3 is turned on, the power consumed by the resistor 3 is wasted. However, as described above, the turning on of the resistor 3 can be extended to the last timing of inrush current generation. Save energy.
  • Step S1 When the voltage Vdc of the smoothing capacitor 4 decreases (NO in Step S1, YES in Step S4), the main control unit 20 determines the magnitude of the load based on the torque component current Iq in the sensorless vector control unit 50 (Step S1). S5).
  • step S5 When it is determined that the load is a light load (YES in step S5), the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the first set value V1 ′ (step S6). When the voltage Vdc of the smoothing capacitor 4 falls below the first set value V1 ′ (YES in step S6), the main control unit 20 sets the relay drive signal D to a low level to turn off the transistor 22 and thereby the relay 30 is deactivated (opening operation) (step S7). When the relay 30 is de-energized, the relay contact 30a is opened, and the resistor 3 is put in the energization path between the converter 2 and the smoothing capacitor 4. Subsequently, the main control unit 20 cancels the output torque reduction described later (step S10).
  • main controller 20 determines that voltage Vdc of smoothing capacitor 4 is decreasing (NO in step S1, YES in step S4), and determines that the load is medium load or heavy load (NO in step S5).
  • the voltage Vdc of the smoothing capacitor 4 is compared with the second set value V2 (step S8).
  • the main control unit 20 outputs the output of the inverter 10 so that the load becomes a light load that is less than a predetermined value.
  • Torque is reduced (step S9).
  • the main control unit 20 reduces the torque component current Iq in the sensorless vector control unit 50 so that the load becomes a light load less than a predetermined value.
  • the main control unit 20 returns to the determination in step S1 after reducing the torque component current Iq. If the voltage Vdc continues to decrease (NO in step S1, YES in step S4), the main control unit 20 determines whether the load has become a light load (step S5).
  • step S5 If the magnitude of the load is reduced to a light load (YES in step S5), the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the first set value V1 ′ (step S6). When the voltage Vdc of the smoothing capacitor 4 falls below the first set value V1 ′ (YES in step S6), the main control unit 20 sets the relay drive signal D to a low level to turn off the transistor 22, Thus, the relay 30 is de-energized (step S7). When the relay 30 is de-energized, the relay contact 30a is opened, and the resistor 3 is put in the energization path between the converter 2 and the smoothing capacitor 4.
  • the main control unit 20 cancels the reduction of the torque component current Iq (output torque reduction) in the sensorless vector control unit 50 (step S10).
  • the voltage Vdc of the smoothing capacitor 4 is lowered and the load is a light load with a magnitude less than a predetermined value
  • the voltage Vdc is higher than the minimum voltage value V1 for preventing inrush current. Since the relay 30 is deenergized at a timing lower than ', even if there is a time delay in opening and closing the relay contact 30a, an inrush current can be reliably prevented.
  • the output torque of the inverter 10 is reduced so that the load size becomes a light load less than the predetermined value, thereby reducing the rate of decrease in the voltage Vdc. Since the speed is reduced to the lowering speed at light load, the lowering of the voltage Vdc can be reliably captured. That is, inrush current can be reliably prevented without being affected by the size of the load. Other effects are the same as those of the first embodiment.
  • the main control unit 20 has the following means (11) to (13) as main functions.
  • Second control means for opening the relay contact 30a by opening the relay 30 when the voltage Vdc of the smoothing capacitor 4 falls below the first set value V1 ′.
  • step S1 When the voltage Vdc of the smoothing capacitor 4 increases (YES in step S1), the main control unit 20 cancels the allowable minimum operating frequency Fmin described later (step S1a), and cancels the voltage Vdc and the second voltage Vdc. 2
  • the set value V2 is compared (step S2).
  • the main control unit 20 sets the relay drive signal D to a high level based on the determination that the inrush current has been eliminated.
  • the transistor 22 is turned on, thereby energizing (closing operation) the relay 30 (step S3).
  • steps S1 to S3 is different from the first and second embodiments only in that the process of step S1a is added.
  • step S11 When the voltage Vdc of the smoothing capacitor 4 falls (NO in step S1, YES in step S4), the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the first set value V1 ′ (step S11).
  • the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the second set value V2 (step S12).
  • the main control unit 20 sets the torque component current Iq in the sensorless vector control unit 50 to a negative value, thereby The inverter 10 is operated in the regeneration mode (step S13).
  • the inverter 10 operates in the regenerative mode, the voltage Vdc of the smoothing capacitor 4 turns upward and the output frequency F of the inverter 10 gradually decreases.
  • step S14 When the output frequency F of the inverter 10 decreases to the allowable minimum operating frequency Fmin (YES in step S14), the main control unit 20 returns the torque component current Iq to a positive value and ends the operation of the inverter 10 in the regeneration mode. At the same time (step S15), the output torque (torque component current Iq) of the inverter 10 is controlled so that the output frequency F of the inverter 10 maintains the allowable minimum operating frequency Fmin (step S16). Then, the main control unit 20 returns to the process of step S1 while continuing this output torque control.
  • step S18 When the voltage Vdc of the smoothing capacitor 4 falls below the set value V1 ′ while continuing the output torque control of the inverter 10 (NO in step S1, YES in step S4, YES in step S11), the main control unit 20 deactivates the relay 30 (step S17), and cancels the control for maintaining the output frequency F at the allowable minimum operating frequency Fmin (output torque control of the inverter 10) (step S18).
  • the relay 30 is de-energized at a timing when the voltage Vdc falls below the first set value V1 ′ that is higher than the minimum voltage value V1 for preventing inrush current. Even if there is a time delay in opening and closing the relay contact 30a, inrush current can be reliably prevented.
  • the inverter 10 when the voltage Vdc of the smoothing capacitor 4 is lowered, the inverter 10 is operated in the regeneration mode at a timing when the voltage Vdc falls below the second specified value V2 higher than the first set value V1 ′, and the smoothing capacitor 4 is generated by the regenerative energy. Since the voltage Vdc is once changed to the rising side, the introduction of the resistor 3 based on the first set value V1 ′ can be made as late as possible. Thereby, the power loss in the resistor 3 can be reduced. Stopping of the inverter 10 based on the set value V0 can be avoided as much as possible. Other effects are the same as those of the first embodiment.
  • the magnitude of the load of the brushless DC motor M is determined by the magnitude of the fluctuation of the voltage Vdc of the smoothing capacitor 4.
  • the main control unit 20 has the following means (21) to (24) as main functions.
  • (21) The voltage of the smoothing capacitor 4 when the commercial three-phase AC power supply 1 is stable is obtained as a reference voltage, and the difference between the reference voltage and the voltage of the smoothing capacitor 4 (the detection voltage of the voltage detection unit 21) Vdc at this time Calculation means for obtaining the change amount ⁇ Vdc.
  • the reference voltage for example, an average value Vdcx of the voltage Vdc of the smoothing capacitor 4 over a predetermined time is obtained.
  • the average value Vdcx is a value obtained by integrating the voltage Vdc over a long period of time, and is obtained by, for example, low-pass filter processing with a large time constant.
  • First control means for closing the relay contact 30a by closing the relay 30 when the voltage of the smoothing capacitor 4 (detection voltage of the voltage detection unit 21) Vdc rises to the second set value V2 or more.
  • Third control means for opening the relay contact 30a by opening the relay 30 when the determination result is a medium load or a heavy load and the voltage Vdc of the smoothing capacitor 4 falls below the second set value V2.
  • Other configurations are the same as those of the first embodiment.
  • the main control unit 20 sequentially obtains an average value Vdcx of the voltage Vdc of the smoothing capacitor 4 by, for example, a low-pass filter process having a large time constant, and calculates a difference between the average value Vdcx and the current voltage Vdc of the smoothing capacitor 4 as a voltage change amount. It calculates as (DELTA) Vdc (step S0).
  • the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the specified value V2 when the voltage Vdc of the smoothing capacitor 4 increases (YES in Step S1) (Step S2).
  • the main control unit 20 sets the relay drive signal D to a high level based on the determination that the inrush current has been eliminated.
  • the transistor 22 is turned on, thereby energizing (closing operation) the relay 30 (step S3). By this energization, the relay contact 30 a is closed, a short circuit path for the resistor 3 is formed, and the resistor 3 is disconnected from the energization path between the converter 2 and the smoothing capacitor 4.
  • step S5a When the voltage Vdc of the smoothing capacitor 4 decreases (NO in step S1, YES in step S4), the main control unit 20 compares the obtained voltage change amount ⁇ Vdc with the predetermined amount ⁇ Vs (step S5a).
  • step S5a When the voltage change amount ⁇ Vdc is as small as less than the predetermined amount ⁇ Vs (YES in step S5a), the main control unit 20 determines that the load is a light load less than the predetermined value and the voltage Vdc of the smoothing capacitor 4 1 set value V1 'is compared (step S6). When the voltage Vdc of the smoothing capacitor 4 falls below the set value V1 ′ (YES in step S6), the main control unit 20 sets the relay drive signal D to a low level to turn off the transistor 22 and thereby the relay 30 is deactivated (step S7). By deactivating the relay 30, the relay contact 30a is opened and the resistor 3 is turned on.
  • the main control unit 20 determines the voltage of the smoothing capacitor 4 based on the determination that the load is a medium load or a heavy load greater than the predetermined value. Vdc and the second set value V2 are compared (step S8). When the voltage Vdc of the smoothing capacitor 4 falls below the second set value V2 (YES in step S8), the main control unit 20 sets the relay drive signal D to a low level and turns off the transistor 22, thereby The relay 30 is de-energized (step S7). By deactivating the relay 30, the relay contact 30a is opened and the resistor 3 is turned on.
  • the average value Vdcx of the voltage Vdc of the smoothing capacitor 4 is sequentially obtained as the reference voltage, and the difference between the average value Vdcx and the current voltage Vdc of the smoothing capacitor 4 is obtained as the voltage change amount ⁇ Vdc.
  • the magnitude of the load is determined from the amount ⁇ Vdc, the first set value V1 ′ is selected for deactivation of the relay 30 at light load, and the second higher than the first set value V1 ′ at medium load or heavy load.
  • the average value Vdcx of the voltage Vdc of the smoothing capacitor 4 is used as the reference voltage.
  • the voltage Vdc before a predetermined time in which a fluctuation such as a drop in the power supply voltage occurs is stored and used as the reference voltage. It may be used as
  • the specified value V2 for relay energization for the rising voltage Vdc is used as it is as the second setting value for relay de-energization for the falling voltage Vdc. It is not limited to. That is, the second set value may be a value higher than the set value V1 ′, and may be determined as appropriate according to the time delay of opening and closing of the relay 30 and the power consumption of the inverter 10.
  • SYMBOLS 1 Commercial three-phase alternating current power supply, 2 ... Converter, 3 ... Resistor for inrush current prevention, 4 ... Room smoothing capacitor, 10 ... Inverter, M ... Brushless DC motor (load), 11, 12, 13 ... Current sensor, DESCRIPTION OF SYMBOLS 20 ... Main control part, 21 ... Voltage detection part, 22 ... NPN type transistor, 30 ... Relay, 30a ... Relay contact, 50 ... Sensorless vector control part

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  • Power Engineering (AREA)
  • Inverter Devices (AREA)
  • Rectifiers (AREA)

Abstract

An inrush current prevention resistor (3) is disposed on the current path between a converter (2) and a smoothing capacitor (4), and the contact (30a) of a relay (30) is connected in parallel with the resistor (3). When the voltage of the smoothing capacitor (4) rises to a specified value or more, the relay (30) is allowed to perform a close operation, and when the voltage of the smoothing capacitor (4) falls to less than a set value, the relay (30) is allowed to perform an open operation. The set value is higher than the minimum voltage value of the smoothing capacitor (4), which is necessary for the current flowing through the converter (2) not to exceed the allowable maximum current of the converter (2). According to this power conversion device, inrush current can be reliably prevented.

Description

電力変換装置Power converter
　本発明の実施形態は、交流電源の電圧を直流に変換し、その直流電圧を所定周波数の交流電圧に変換する電力変換装置に関する。 Embodiment of this invention is related with the power converter device which converts the voltage of AC power supply into DC, and converts the DC voltage into the AC voltage of a predetermined frequency.
　商用交流電源の電圧を直流に変換する整流回路、この整流回路の出力電圧を平滑する平滑コンデンサ、この平滑コンデンサの電圧を所定周波数の交流電圧に変換するインバータを備え、商用交流電源と整流回路との間の電源ラインに突入電流防止用のＰＴＣサーミスタ（温度の上昇に対して抵抗が増大する抵抗器）を挿入接続し、そのＰＴＣサーミスタに対しリレー接点を並列接続した電力変換装置がある。 A rectifier circuit that converts the voltage of the commercial AC power source into DC, a smoothing capacitor that smoothes the output voltage of the rectifier circuit, an inverter that converts the voltage of the smoothing capacitor into an AC voltage of a predetermined frequency, a commercial AC power source and a rectifier circuit, There is a power conversion device in which a PTC thermistor for preventing an inrush current (a resistor whose resistance increases with a rise in temperature) is inserted and connected to a power line between and a relay contact is connected in parallel to the PTC thermistor.
　この電力変換装置では、リレー接点を開いてＰＴＣサーミスタを通電路に投入しておくことにより、電源投入時の突入電流を防止する。 This power converter prevents inrush current when the power is turned on by opening the relay contact and putting the PTC thermistor into the current path.
　その後、平滑コンデンサの電圧が上昇して突入電流の心配がなくなったとき、リレー接点を閉じてＰＴＣサーミスタに対する短絡路を形成し、ＰＴＣサーミスタを切り離す。商用交流電源の電圧が一時的に低下し、平滑コンデンサの電圧が整流回路の出力電圧を下回った場合も、リレー接点を開いてＰＴＣサーミスタを投入し、突入電流を防止する。 After that, when the voltage of the smoothing capacitor rises and there is no worry of inrush current, the relay contact is closed to form a short circuit to the PTC thermistor, and the PTC thermistor is disconnected. Even when the voltage of the commercial AC power supply temporarily decreases and the voltage of the smoothing capacitor falls below the output voltage of the rectifier circuit, the relay contact is opened and a PTC thermistor is turned on to prevent inrush current.
特開２０１１－１８２５６８号公報JP 2011-182568 A
　上記の電力変換装置では、電源ラインに流れる電流が大きく、また半導体スイッチは開閉時の電力損失が無視できないことから、ＰＴＣサーミスタの投入および切り離しにリレーを用いている。ただし、リレーは、電気信号を機械的な接点の動きに変えるものであるため、電気信号を受けてから実際に接点が開閉するまでに数msecの時間遅れが生じる。この時間遅れにより、突入電流を防止できなくなる可能性がある。 In the above power conversion device, since a large current flows through the power supply line, and the semiconductor switch cannot ignore power loss during opening and closing, a relay is used to turn on and off the PTC thermistor. However, since the relay changes an electrical signal into a mechanical contact movement, there is a delay of several milliseconds from when the electrical signal is received until the contact is actually opened and closed. This time delay may prevent the inrush current from being prevented.
　本発明の実施形態の目的は、突入電流を確実に防止できる電力変換装置を提供することである。 An object of an embodiment of the present invention is to provide a power conversion device that can reliably prevent an inrush current.
　請求項１の電力変換装置は、商用交流電源の電圧を直流に変換するコンバータと、このコンバータの出力端に接続された平滑コンデンサと、この平滑コンデンサの電圧を交流電圧に変換し、その交流電圧を負荷への駆動電力として出力するインバータと、前記コンバータと前記平滑コンデンサとの間の通電路に配置された突入電流防止用の抵抗器と、この抵抗器に並列接続された接点を有するリレーと、前記平滑コンデンサの電圧が規定値以上に上昇した場合に前記リレーを閉動作させ、前記平滑コンデンサの電圧が設定値未満に下降した場合に前記リレーを開動作させる制御手段と、を備える。前記設定値は、前記コンバータに流れる電流が同コンバータの許容最大電流を超えないために必要な前記平滑コンデンサの最小電圧値より高い。 The power conversion device according to claim 1 is a converter that converts a voltage of a commercial AC power source into a DC voltage, a smoothing capacitor connected to an output terminal of the converter, a voltage of the smoothing capacitor is converted into an AC voltage, and the AC voltage Output as drive power to the load, a resistor for preventing inrush current disposed in a current path between the converter and the smoothing capacitor, and a relay having a contact connected in parallel to the resistor, Control means for closing the relay when the voltage of the smoothing capacitor rises above a specified value, and opening the relay when the voltage of the smoothing capacitor drops below a set value. The set value is higher than the minimum voltage value of the smoothing capacitor necessary for the current flowing through the converter not to exceed the maximum allowable current of the converter.
図１は、各実施形態の構成を示すブロック図。FIG. 1 is a block diagram showing the configuration of each embodiment. 図２は、第１実施形態の制御を示すフローチャート。FIG. 2 is a flowchart showing the control of the first embodiment. 図３は、第１実施形態における平滑コンデンサの電圧変化、リレー駆動信号の変化、常開接点の変化を示すタイムチャート。FIG. 3 is a time chart showing the voltage change of the smoothing capacitor, the change of the relay drive signal, and the change of the normally open contact in the first embodiment. 図４は、第２実施形態の制御を示すフローチャート。FIG. 4 is a flowchart showing the control of the second embodiment. 図５は、第２実施形態における平滑コンデンサの電圧変化、リレー駆動信号の変化、常開接点の変化を示すタイムチャート。FIG. 5 is a time chart showing a voltage change of a smoothing capacitor, a change of a relay drive signal, and a change of a normally open contact in the second embodiment. 図６は、第３実施形態の制御を示すフローチャート。FIG. 6 is a flowchart showing the control of the third embodiment. 図７は、第３実施形態における平滑コンデンサの電圧変化、リレー駆動信号の変化、常開接点の変化を示すタイムチャート。FIG. 7 is a time chart showing the voltage change of the smoothing capacitor, the change of the relay drive signal, and the change of the normally open contact in the third embodiment. 図８は、第４実施形態の制御を示すフローチャート。FIG. 8 is a flowchart showing the control of the fourth embodiment.
　［１］以下、第１実施形態について図面を参照して説明する。　
　図１に示すように、商用三相交流電源１にコンバータ２が接続される。コンバータ２は、複数のスイッチング素子および複数のダイオードを含み、商用三相交流電源１の交流電圧を直流電圧に変換する。このコンバータ２の出力端に、抵抗器３とリレー接点３０ａとの並列回路を介して、平滑コンデンサ（電解コンデンサ）４が接続される。抵抗器３は、突入電流防止用の例えばＰＴＣサーミスタである。リレー接点３０ａは、リレー３０の常開接点である。 [1] A first embodiment will be described below with reference to the drawings.
As shown in FIG. 1, a converter 2 is connected to a commercial three-phase AC power source 1. Converter 2 includes a plurality of switching elements and a plurality of diodes, and converts the AC voltage of commercial three-phase AC power supply 1 into a DC voltage. A smoothing capacitor (electrolytic capacitor) 4 is connected to the output end of the converter 2 via a parallel circuit of the resistor 3 and the relay contact 30a. The resistor 3 is, for example, a PTC thermistor for preventing inrush current. The relay contact 30 a is a normally open contact of the relay 30.
　そして、平滑コンデンサ４にインバータ１０が接続され、そのインバータ１０の出力端に負荷である例えばブラシレスＤＣモータ（永久磁石同期モータともいう）Ｍが接続される。インバータ１０は、還流用ダイオードがそれぞれ逆並列接続された２つのスイッチング素子Ｔ１，Ｔ２のＵ相直列回路、還流用ダイオードがそれぞれ逆並列接続された２つのスイッチング素子Ｔ３，Ｔ４のＶ相直列回路、還流用ダイオードがそれぞれ逆並列接続された２つのスイッチング素子Ｔ５，Ｔ６のＷ相直列回路を含み、平滑コンデンサ４の電圧を所定周波数の交流電圧に変換し、その交流電圧をブラシレスＤＣモータＭへの駆動電力として出力する。このインバータ１０の各直列回路における両スイッチング素子の相互接続点に、ブラシレスＤＣモータＭの相巻線Ｌｕ，Ｌｖ，Ｌｗがそれぞれ接続される。 Then, an inverter 10 is connected to the smoothing capacitor 4, and a load, for example, a brushless DC motor (also referred to as a permanent magnet synchronous motor) M is connected to the output terminal of the inverter 10. The inverter 10 includes a U-phase series circuit of two switching elements T1 and T2 each having a reflux diode connected in antiparallel, and a V-phase series circuit of two switching elements T3 and T4 each having a reflux diode connected in antiparallel, It includes a W-phase series circuit of two switching elements T5 and T6 each having a reverse diode connected in reverse parallel, converts the voltage of the smoothing capacitor 4 into an AC voltage of a predetermined frequency, and converts the AC voltage to the brushless DC motor M. Output as drive power. Phase windings Lu, Lv, and Lw of the brushless DC motor M are connected to interconnection points of both switching elements in each series circuit of the inverter 10, respectively.
　上記リレー３０に、ＮＰＮ型トランジスタ２２のコレクタ・エミッタを介して、直流電圧Ｖｄが印加される。ＮＰＮ型トランジスタ２２のベースは、主制御部２０に接続される。ＮＰＮ型トランジスタ２２は、主制御部２０から供給されるリレー駆動信号Ｄが高レベルのときにオンし、リレー駆動信号Ｄが低レベルのときにオフする。ＮＰＮ型トランジスタ２２がオンすると、リレー３０の励磁コイルが付勢されてリレー接点３０ａが閉じる。つまり、リレー３０が閉動作する。ＮＰＮ型トランジスタ２２がオフすると、リレー３０の励磁コイルが消勢されてリレー接点３０ａが開く。つまり、リレー３０が開動作する。 The DC voltage Vd is applied to the relay 30 via the collector / emitter of the NPN transistor 22. The base of the NPN transistor 22 is connected to the main controller 20. The NPN transistor 22 is turned on when the relay drive signal D supplied from the main controller 20 is at a high level, and turned off when the relay drive signal D is at a low level. When the NPN transistor 22 is turned on, the exciting coil of the relay 30 is energized and the relay contact 30a is closed. That is, the relay 30 is closed. When the NPN transistor 22 is turned off, the exciting coil of the relay 30 is de-energized and the relay contact 30a is opened. That is, the relay 30 opens.
　上記平滑コンデンサ４の両端に、電圧検出部２１が接続される。電圧検出部２１は、平滑コンデンサ４に生じる電圧Ｖｄｃを検出する。この電圧検出部２１が主制御部２０に接続される。 The voltage detector 21 is connected to both ends of the smoothing capacitor 4. The voltage detector 21 detects the voltage Vdc generated in the smoothing capacitor 4. This voltage detector 21 is connected to the main controller 20.
　上記インバータ１０の出力端とブラシレスＤＣモータＭとの間の各相通電ラインに、電流センサ（電流トランス）１１，１２，１３が配置される。電流センサ１１，１２，１３は、ブラシレスＤＣモータＭの相巻線Ｌｕ，Ｌｖ，Ｌｗに流れる電流（相電流）をそれぞれ検知する。これら電流センサ１１，１２，１３が主制御部２０に接続される。 Current sensors (current transformers) 11, 12, and 13 are disposed on each phase energization line between the output terminal of the inverter 10 and the brushless DC motor M. Current sensors 11, 12, and 13 detect currents (phase currents) flowing through the phase windings Lu, Lv, and Lw of the brushless DC motor M, respectively. These current sensors 11, 12, and 13 are connected to the main control unit 20.
　主制御部２０には、さらに、センサレス・ベクトル制御部５０が接続される。センサレス・ベクトル制御部５０は、電流検出部５１、速度推定演算部５２、積分部５３、減算部５４、速度制御部５５、演算部５６、減算部５７，５８、電流制御部（第１電流制御部）６１、電流制御部（第２電流制御部）６２、ＰＷＭ信号生成部６３を含む。 The sensorless vector controller 50 is further connected to the main controller 20. The sensorless vector control unit 50 includes a current detection unit 51, a speed estimation calculation unit 52, an integration unit 53, a subtraction unit 54, a speed control unit 55, a calculation unit 56, subtraction units 57 and 58, a current control unit (first current control). Unit) 61, a current control unit (second current control unit) 62, and a PWM signal generation unit 63.
　電流検出部５１は、電流センサ１１，１２，１３の検知電流を３相２相変換して、ブラシレスＤＣモータＭにおけるロータ軸上の界磁軸（ｄ軸）座標およびトルク軸（ｑ軸）座標にそれぞれ換算された界磁成分電流（ｄ軸電流ともいう）Ｉｄおよびトルク成分電流（ｑ軸電流ともいう）Ｉｑを検出する。速度推定演算部５２は、電流検出部５１で検出された界磁成分電流Ｉｄおよびトルク成分電流Ｉｑに基づく演算により、ブラシレスＤＣモータＭのロータ速度ωestを推定する。具体的には、界磁成分電流Ｉｄと、トルク成分電流Ｉｑと、電流制御部６１で求められる界磁成分電圧Ｖｄと、電流制御部６２で求められるトルク成分電圧Ｖｑとを用いる演算により、ブラシレスＤＣモータＭにおける界磁成分速度起電力（ｄ軸速度起電力という）Ｅｄを推定し、このｄ軸速度起電力Ｅｄの比例・積分制御（ＰＩ制御）演算に基づいて推定ロータ速度ωestを求める。 The current detection unit 51 performs three-phase to two-phase conversion on the detection currents of the current sensors 11, 12, and 13, and field axis (d axis) coordinates and torque axis (q axis) coordinates on the rotor axis in the brushless DC motor M. Are converted to field component current (also referred to as d-axis current) Id and torque component current (also referred to as q-axis current) Iq. The speed estimation calculation unit 52 estimates the rotor speed ωest of the brushless DC motor M by calculation based on the field component current Id and the torque component current Iq detected by the current detection unit 51. Specifically, brushless operation is performed by calculation using the field component current Id, the torque component current Iq, the field component voltage Vd obtained by the current control unit 61, and the torque component voltage Vq obtained by the current control unit 62. A field component speed electromotive force (referred to as d-axis speed electromotive force) Ed in the DC motor M is estimated, and an estimated rotor speed ωest is obtained based on a proportional / integral control (PI control) calculation of the d-axis speed electromotive force Ed.
　積分部５３は、速度推定演算部５２で求められた推定ロータ速度ωestを積分することにより、推定ロータ位置θestを得る。この推定ロータ位置θestは、電流検出部５１およびＰＷＭ信号生成部６３に供給される。減算部５４は、主制御部２０から指令される目標速度ωrefから推定ロータ速度ωestを減算することにより、目標速度ωrefと推定ロータ速度ωestとの速度偏差を得る。速度制御部５５は、減算部５４で得られた速度偏差を比例・積分制御（ＰＩ制御）演算することにより、トルク成分電流Ｉｑの目標値Ｉｑrefを求める。演算部５６は、トルク成分電流Ｉｑの目標値Ｉｑrefから界磁成分電流Ｉｄの目標値Ｉｄrefを求める。減算部５７は、目標値Ｉｄrefから界磁成分電流Ｉｄを減算することにより、目標値Ｉｄrefと界磁成分電流Ｉｄとの偏差ΔＩｄを得る。減算部５８は、目標値Ｉｑrefからトルク成分電流Ｉｑを減算することにより、目標値Ｉｑrefとトルク成分電流Ｉｑとの偏差ΔＩｑを得る。 The integrating unit 53 obtains an estimated rotor position θest by integrating the estimated rotor speed ωest obtained by the speed estimation calculating unit 52. The estimated rotor position θest is supplied to the current detection unit 51 and the PWM signal generation unit 63. The subtracting unit 54 obtains a speed deviation between the target speed ωref and the estimated rotor speed ωest by subtracting the estimated rotor speed ωest from the target speed ωref commanded from the main control unit 20. The speed control unit 55 calculates a target value Iqref of the torque component current Iq by calculating a proportional / integral control (PI control) on the speed deviation obtained by the subtracting unit 54. The calculation unit 56 obtains the target value Idref of the field component current Id from the target value Iqref of the torque component current Iq. The subtracting unit 57 obtains a deviation ΔId between the target value Idref and the field component current Id by subtracting the field component current Id from the target value Idref. The subtraction unit 58 obtains a deviation ΔIq between the target value Iqref and the torque component current Iq by subtracting the torque component current Iq from the target value Iqref.
　電流制御部６１は、偏差ΔＩｄの比例・積分制御（ＰＩ制御）演算により、ブラシレスＤＣモータＭにおけるロータ軸上のｄ軸座標に換算した界磁成分電圧Ｖｄを求める。電流制御部６２は、偏差ΔＩｑの比例・積分制御（ＰＩ制御）演算により、ブラシレスＤＣモータＭにおけるロータ軸上のｑ軸座標に換算したトルク成分電圧Ｖｑを求める。ＰＷＭ信号生成部６３は、界磁成分電圧Ｖｄ、トルク成分電圧Ｖｑ、および推定ロータ位置θestに応じて、インバータ１０に対するスイッチング用のパルス幅変調信号(ＰＷＭ信号という)を生成する。このＰＷＭ信号により、インバータ１０のスイッチング素子Ｔ１～Ｔ６がオン，オフ動作し、ブラシレスＤＣモータＭの相巻線Ｌｕ，Ｌｖ，Ｌｗに対する駆動電圧Ｖｕ，Ｖｖ，Ｖｗがインバータ１０から出力される。これにより、ブラシレスＤＣモータＭの速度が短時間で目標速度となるように制御される。 The current control unit 61 obtains the field component voltage Vd converted into the d-axis coordinate on the rotor shaft in the brushless DC motor M by the proportional / integral control (PI control) calculation of the deviation ΔId. The current control unit 62 obtains a torque component voltage Vq converted into q-axis coordinates on the rotor shaft in the brushless DC motor M by proportional / integral control (PI control) calculation of the deviation ΔIq. The PWM signal generation unit 63 generates a switching pulse width modulation signal (referred to as a PWM signal) for the inverter 10 according to the field component voltage Vd, the torque component voltage Vq, and the estimated rotor position θest. With this PWM signal, the switching elements T1 to T6 of the inverter 10 are turned on and off, and drive voltages Vu, Vv, and Vw for the phase windings Lu, Lv, and Lw of the brushless DC motor M are output from the inverter 10. Thus, the speed of the brushless DC motor M is controlled so as to reach the target speed in a short time.
　主制御部２０は、主要な機能として次の（１）～（３）の手段を有する。　
　（１）平滑コンデンサ４の電圧（電圧検出部２１の検出電圧）Ｖｄｃが予め定めた規定値Ｖ２以上に上昇した場合に、リレー３０を閉動作させてリレー接点３０ａを閉じる第１制御手段。 The main control unit 20 has the following means (1) to (3) as main functions.
(1) First control means for closing the relay contact 30a by closing the relay 30 when the voltage of the smoothing capacitor 4 (detection voltage of the voltage detection unit 21) Vdc rises to a predetermined value V2 or more.
　（２）負荷の大きさが所定値未満（軽負荷）で且つ平滑コンデンサ４の電圧Ｖｄｃが予め定めた第１設定値Ｖ１´（＜Ｖ２）未満に下降した場合に、リレー３０を開動作させてリレー接点３０ａを開く第２制御手段。第１設定値Ｖ１´は、規定値Ｖ２以下であって、コンバータ２に流れる電流が同コンバータ２の許容最大電流を超えないために必要な平滑コンデンサ４の最小電圧値Ｖ１より所定値だけ高い値である。コンバータ２の許容最大電流は、例えば、コンバータ２におけるスイッチング素子やダイオードの最大定格電流である。 (2) When the magnitude of the load is less than a predetermined value (light load) and the voltage Vdc of the smoothing capacitor 4 falls below a predetermined first set value V1 ′ (<V2), the relay 30 is opened. Second control means for opening the relay contact 30a. The first set value V1 ′ is a specified value V2 or less, and is a value that is higher by a predetermined value than the minimum voltage value V1 of the smoothing capacitor 4 that is necessary for the current flowing through the converter 2 not to exceed the allowable maximum current of the converter 2. It is. The allowable maximum current of the converter 2 is, for example, the maximum rated current of a switching element or a diode in the converter 2.
　（３）負荷の大きさが所定値以上（中負荷または重負荷）で且つ平滑コンデンサ４の電圧Ｖｄｃが上記第１設定値Ｖ１´より高い第２設定値未満に下降した場合に、リレー３０を開動作させてリレー接点３０ａを開く第３制御手段。第２設定値として、例えば規定値Ｖ２を用いる。以下、規定値の符号“Ｖ２”を第２設定値にも付ける。 (3) When the magnitude of the load is equal to or greater than a predetermined value (medium load or heavy load) and the voltage Vdc of the smoothing capacitor 4 falls below a second set value that is higher than the first set value V1 ′, the relay 30 is turned on. Third control means for opening and opening the relay contact 30a. For example, a specified value V2 is used as the second set value. Hereinafter, the reference value “V2” is also attached to the second set value.
　つぎに、主制御部２０が実行する制御を図２のフローチャートおよび図３のタイムチャートを参照しながら説明する。　
　商用三相交流電源１が投入されると、その商用三相交流電源１の電圧がコンバータ２で直流電圧Ｖａに変換され、その直流電圧Ｖａが平滑コンデンサ４に印加される。この印加により、平滑コンデンサ４の電圧Ｖｄｃが上昇する。 Next, the control executed by the main control unit 20 will be described with reference to the flowchart of FIG. 2 and the time chart of FIG.
When the commercial three-phase AC power source 1 is turned on, the voltage of the commercial three-phase AC power source 1 is converted into a DC voltage Va by the converter 2, and the DC voltage Va is applied to the smoothing capacitor 4. By this application, the voltage Vdc of the smoothing capacitor 4 increases.
　この電源投入時、コンバータ２の出力電圧Ｖａと平滑コンデンサ４の電圧Ｖｄｃとの差“Ｖａ－Ｖｄｃ”および商用三相交流電源１から平滑コンデンサ４までのラインインピーダンスＺに応じた突入電流Ｉｘ＝（Ｖａ－Ｖｄｃ）／Ｚが、コンバータ２から平滑コンデンサ４に流れようとする。しかしながら、コンバータ２と平滑コンデンサ４との間の通電路にはリレー接点３０ａの開放によって抵抗器３が投入された状態にあるので、実際に流れる電流は、抵抗器３の抵抗値Ｒが加わる分だけ抑制された電流Ｉｙ＝（Ｖａ－Ｖｄｃ）／（Ｚ＋Ｒ）である。この電流Ｉｙは、コンバータ２の許容最大電流を超えない値である。よって、コンバータ２のスイッチング素子やダイオードの破壊を防ぐことができる。 When the power is turned on, the inrush current Ix = (in accordance with the difference “Va−Vdc” between the output voltage Va of the converter 2 and the voltage Vdc of the smoothing capacitor 4 and the line impedance Z from the commercial three-phase AC power supply 1 to the smoothing capacitor 4. Va−Vdc) / Z tends to flow from the converter 2 to the smoothing capacitor 4. However, since the resistor 3 is put in the energization path between the converter 2 and the smoothing capacitor 4 by opening the relay contact 30a, the current that actually flows is equivalent to the resistance value R of the resistor 3 being added. Only suppressed current Iy = (Va−Vdc) / (Z + R). This current Iy is a value that does not exceed the maximum allowable current of converter 2. Therefore, destruction of the switching element and the diode of the converter 2 can be prevented.
　平滑コンデンサ４の電圧Ｖｄｃの上昇時（ステップＳ１のＹＥＳ）、主制御部２０は、平滑コンデンサ４の電圧Ｖｄｃと規定値（＝第２設定値）Ｖ２とを比較する（ステップＳ２）。そして、電圧Ｖｄｃが規定値Ｖ２に達したとき（ステップＳ２のＹＥＳ）、主制御部２０は、突入電流の心配がなくなったとの判断の下に、リレー駆動信号Ｄを高レベルに設定してトランジスタ２２をオンし、これによりリレー３０を付勢（閉動作）する（ステップＳ３）。この付勢により、リレー接点３０ａが閉じて抵抗器３に対する短絡路が形成される。つまり、コンバータ２と平滑コンデンサ４との間の通電路から抵抗器３が切り離された状態となる。なお、リレー接点３０ａは機械的に動くいわゆるメカニカル接点であるため、リレー駆動信号Ｄが高レベルに設定されてから実際にリレー接点３０ａが閉じるまでに、数msecの時間遅れｔ２が生じる。 When the voltage Vdc of the smoothing capacitor 4 increases (YES in Step S1), the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with a specified value (= second set value) V2 (Step S2). When the voltage Vdc reaches the specified value V2 (YES in step S2), the main control unit 20 sets the relay drive signal D to a high level and determines that the inrush current is no longer a concern. 22 is turned on, thereby energizing (closing operation) the relay 30 (step S3). By this energization, the relay contact 30a is closed and a short circuit path for the resistor 3 is formed. That is, the resistor 3 is disconnected from the energization path between the converter 2 and the smoothing capacitor 4. Since the relay contact 30a is a so-called mechanical contact that moves mechanically, a time delay t2 of several milliseconds occurs after the relay drive signal D is set to a high level until the relay contact 30a is actually closed.
　一方、商用三相交流電源１に電圧低下が生じた場合、その電源電圧の低下に伴ってコンバータ２の出力電圧Ｖａも低下する。この場合、負荷であるブラシレスＤＣモータＭへの電力供給は続くため、平滑コンデンサ４の電圧Ｖｄｃが下降することがある。 On the other hand, when a voltage drop occurs in the commercial three-phase AC power supply 1, the output voltage Va of the converter 2 also drops as the power supply voltage drops. In this case, since the power supply to the brushless DC motor M as a load continues, the voltage Vdc of the smoothing capacitor 4 may decrease.
　平滑コンデンサ４の電圧Ｖｄｃの下降時（ステップＳ１のＮＯ、ステップＳ４のＹＥＳ）、主制御部２０は、センサレス・ベクトル制御部５０におけるトルク成分電流Ｉｑに基づき、負荷の大きさを判定する（ステップＳ５）。具体的には、主制御部２０は、トルク成分電流Ｉｑが一定値未満の場合は負荷の大きさが所定値未満の軽負荷であると判定し、トルク成分電流Ｉｑが一定値以上の場合は負荷の大きさが所定値以上の中負荷または重負荷であると判定する。 When the voltage Vdc of the smoothing capacitor 4 decreases (NO in Step S1, YES in Step S4), the main control unit 20 determines the magnitude of the load based on the torque component current Iq in the sensorless vector control unit 50 (Step S1). S5). Specifically, when the torque component current Iq is less than a certain value, the main control unit 20 determines that the load is a light load with a value less than a predetermined value, and when the torque component current Iq is greater than or equal to a certain value. It is determined that the load is a medium load or a heavy load greater than or equal to a predetermined value.
　主制御部２０は、負荷の大きさが軽負荷であると判定した場合（ステップＳ５のＹＥＳ）、平滑コンデンサ４の電圧Ｖｄｃと第１設定値Ｖ１´とを比較する（ステップＳ６）。そして、平滑コンデンサ４の電圧Ｖｄｃが第１設定値Ｖ１´を下回ったとき（ステップＳ６のＹＥＳ）、主制御部２０は、リレー駆動信号Ｄを低レベルに設定してトランジスタ２２をオフし、これによりリレー３０を消勢（開動作）する（ステップＳ７）。リレー３０が消勢されると、リレー接点３０ａが開き、コンバータ２と平滑コンデンサ４との間の通電路に抵抗器３が投入された状態となる。 The main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the first set value V1 ′ (step S6) when determining that the load is a light load (YES in step S5). When the voltage Vdc of the smoothing capacitor 4 falls below the first set value V1 ′ (YES in step S6), the main control unit 20 sets the relay drive signal D to a low level to turn off the transistor 22, Thus, the relay 30 is de-energized (opening operation) (step S7). When the relay 30 is de-energized, the relay contact 30a is opened, and the resistor 3 is put in the energization path between the converter 2 and the smoothing capacitor 4.
　リレー接点３０ａは機械的に動くいわゆるメカニカル接点であるため、リレー駆動信号Ｄが低レベルに設定されてから実際にリレー接点３０ａが開くまでに数msecの時間遅れｔ１が生じる。ただし、突入電流防止のために必要な最小電圧値Ｖ１よりも高い第１設定値Ｖ１´をリレー３０の消勢用として選択しているので、電圧Ｖｄｃが最小電圧値Ｖ１以下に下降する前に、リレー接点３０ａが開いて抵抗器３が投入される。したがって、電圧Ｖｄｃが最小電圧値Ｖ１を下回っても、その時点ではすでに抵抗器３が投入された状態にあるので、突入電流は生じない。つまり、コンバータ２の半導体スイッチやダイオードの破壊を未然に防ぐことができる。 Since the relay contact 30a is a mechanical contact that moves mechanically, a time delay t1 of several milliseconds occurs after the relay drive signal D is set to a low level until the relay contact 30a is actually opened. However, since the first set value V1 ′ higher than the minimum voltage value V1 necessary for preventing the inrush current is selected for deactivating the relay 30, before the voltage Vdc drops below the minimum voltage value V1. The relay contact 30a is opened and the resistor 3 is turned on. Therefore, even if the voltage Vdc falls below the minimum voltage value V1, since the resistor 3 is already turned on at that time, no inrush current occurs. That is, the semiconductor switch and the diode of the converter 2 can be prevented from being destroyed.
　一方、平滑コンデンサ４の電圧Ｖｄｃの下降時、負荷の大きさが中負荷または重負荷である場合は、平滑コンデンサ４の電圧Ｖｄｃの下降速度が速くなる。 On the other hand, when the voltage Vdc of the smoothing capacitor 4 is lowered, if the load is a medium load or a heavy load, the falling speed of the voltage Vdc of the smoothing capacitor 4 is increased.
　主制御部２０は、平滑コンデンサ４の電圧Ｖｄｃの下降時（ステップＳ１のＮＯ、ステップＳ４のＹＥＳ）、かつ負荷の大きさが中負荷または重負荷であると判定した場合（ステップＳ５のＮＯ）、平滑コンデンサ４の電圧Ｖｄｃと第２設定値（＝規定値）Ｖ２とを比較する（ステップＳ８）。そして、平滑コンデンサ４の電圧Ｖｄｃが第２設定値Ｖ２を下回ったとき（ステップＳ８のＹＥＳ）、主制御部２０は、リレー駆動信号Ｄを低レベルに設定してトランジスタ２２をオフし、これによりリレー３０を消勢する（ステップＳ７）。リレー３０が消勢されると、リレー接点３０ａが開き、コンバータ２と平滑コンデンサ４との間の通電路に抵抗器３が投入された状態となる。 When main controller 20 determines that voltage Vdc of smoothing capacitor 4 is decreasing (NO in step S1, YES in step S4), and determines that the load is medium load or heavy load (NO in step S5). The voltage Vdc of the smoothing capacitor 4 is compared with the second set value (= specified value) V2 (step S8). When the voltage Vdc of the smoothing capacitor 4 falls below the second set value V2 (YES in step S8), the main control unit 20 sets the relay drive signal D to a low level and turns off the transistor 22, thereby The relay 30 is de-energized (step S7). When the relay 30 is de-energized, the relay contact 30a is opened, and the resistor 3 is put in the energization path between the converter 2 and the smoothing capacitor 4.
　この場合、負荷の大きさが中負荷または重負荷なので電圧Ｖｄｃの下降速度が速く、しかもリレー駆動信号Ｄが低レベルに設定されてから実際にリレー接点３０ａが開くまでに数msecの時間遅れｔ１が生じるが、第１設定値Ｖ１´より高い第２設定値Ｖ２をリレー３０の消勢用として選択しているので、電圧Ｖｄｃが最小電圧値Ｖ１まで下降する前にリレー接点３０ａが開いて抵抗器３が投入される。つまり、電圧Ｖｄｃが最小電圧値Ｖ１を下回っても、その時点ではすでに抵抗器３が投入された状態にあるので、突入電流は生じない。したがって、コンバータ２の半導体スイッチやダイオードの破壊を未然に防ぐことができる。 In this case, since the load is a medium load or a heavy load, the voltage Vdc descends quickly, and a time delay t1 of several msec from when the relay drive signal D is set to a low level until the relay contact 30a is actually opened. However, since the second set value V2 higher than the first set value V1 ′ is selected for deactivating the relay 30, the relay contact 30a is opened before the voltage Vdc drops to the minimum voltage value V1, and the resistance is reduced. Container 3 is turned on. That is, even when the voltage Vdc falls below the minimum voltage value V1, since the resistor 3 is already turned on at that time, no inrush current occurs. Therefore, destruction of the semiconductor switch and the diode of the converter 2 can be prevented.
　なお、平滑コンデンサ４の電圧Ｖｄｃが突入電流防止用の最小電圧値Ｖ１より低い設定値Ｖ０まで下降した場合、主制御部２０は、インバータ１０のスイッチングを停止する。 In addition, when the voltage Vdc of the smoothing capacitor 4 falls to the set value V0 lower than the minimum voltage value V1 for preventing inrush current, the main control unit 20 stops switching of the inverter 10.
　以上のように、電圧Ｖｄｃの下降時は、電圧Ｖｄｃが突入電流防止用の最小電圧値Ｖ１よりも高い第１設定値Ｖ１´または第２設定値Ｖ２を下回るタイミングでリレー３０を消勢するので、たとえリレー接点３０ａの開閉に時間遅れがあっても、突入電流を確実に防止できる。 As described above, when the voltage Vdc drops, the relay 30 is de-energized at a timing when the voltage Vdc falls below the first set value V1 ′ or the second set value V2 that is higher than the minimum voltage value V1 for preventing inrush current. Even if there is a time delay in opening and closing the relay contact 30a, the inrush current can be reliably prevented.
　しかも、軽負荷時は第１設定値Ｖ１´をリレー３０の消勢用として選択し、中負荷時または重負荷時は第１設定値Ｖ１´より高い第２設定値（＝規定値）Ｖ２をリレー３０の消勢用として選択するので、負荷の大きさに影響を受けることなく、突入電流を確実に防止できる。 Moreover, the first set value V1 ′ is selected for de-energizing the relay 30 at light load, and the second set value (= specified value) V2 higher than the first set value V1 ′ is selected at medium load or heavy load. Since the relay 30 is selected for deactivation, the inrush current can be reliably prevented without being affected by the magnitude of the load.
　第１設定値Ｖ１´と突入電流防止用の最小電圧値Ｖ１との差については、重負荷時の急激な電圧Ｖｄｃの低下があっても、リレー接点３０ａの開閉時間遅れｔ２の間に電圧Ｖｄｃが突入電流防止用の最小電圧値Ｖ１に至ることのない最小限の値が選定される。これにより、抵抗器３の投入を突入電流発生のぎりぎりのタイミングまで延ばすことができる。 Regarding the difference between the first set value V1 ′ and the minimum voltage value V1 for preventing the inrush current, the voltage Vdc is applied during the switching time delay t2 of the relay contact 30a even if there is a sudden drop in the voltage Vdc at the time of heavy load. Is selected to a minimum value that does not reach the minimum voltage value V1 for preventing inrush current. Thereby, the introduction of the resistor 3 can be extended to the last timing of inrush current generation.
　抵抗器３が投入されると、入力電力（電流）が制限される。この入力電力がインバータ１０の駆動可能電力に満たなくなった場合には、インバータ１０を駆動できなくなる。ただし、上記のように、抵抗器３の投入を突入電流発生のぎりぎりのタイミングまで延ばすことができるので、入力電力の制限によるインバータ１０の駆動停止をできるだけ先延ばしにすることができる。結果として、インバータ１０の稼働率を高めることができる。また、抵抗器３を投入すると、その抵抗器３で消費される電力が無駄になるが、上記のように抵抗器３の投入を突入電流発生のぎりぎりのタイミングまで延ばすことができるので、その分、省エネルギとなる。 When the resistor 3 is turned on, the input power (current) is limited. When this input power is less than the driveable power of the inverter 10, the inverter 10 cannot be driven. However, as described above, the insertion of the resistor 3 can be extended until the timing of the inrush current generation, so that the drive stop of the inverter 10 due to the limitation of the input power can be postponed as much as possible. As a result, the operation rate of the inverter 10 can be increased. In addition, when the resistor 3 is turned on, the power consumed by the resistor 3 is wasted. However, as described above, the turning on of the resistor 3 can be extended to the last timing of inrush current generation. Save energy.
　［２］第２実施形態について説明する。　
　主制御部２０は、主要な機能として、第１実施形態の（３）の第３制御手段に代えて、次の（３ａ）の第３制御手段を有する。　
　（３ａ）負荷の大きさが所定値以上（中負荷または重負荷）で且つ平滑コンデンサ４の電圧Ｖｄｃが第２設定値（＝規定値）Ｖ２未満に下降した場合に、負荷の大きさが所定値未満となるようにインバータ１０の出力トルクを低減する第３制御手段。　
　他の構成は第１実施形態と同じである。 [2] A second embodiment will be described.
The main control unit 20 has the following third control means (3a) instead of the third control means (3) of the first embodiment as a main function.
(3a) When the magnitude of the load is equal to or greater than a predetermined value (medium load or heavy load) and the voltage Vdc of the smoothing capacitor 4 falls below the second set value (= specified value) V2, the magnitude of the load is predetermined. Third control means for reducing the output torque of the inverter 10 so as to be less than the value.
Other configurations are the same as those of the first embodiment.
　主制御部２０が実行する制御を図４のフローチャートおよび図５のタイムチャートを参照しながら説明する。　
　平滑コンデンサ４の電圧Ｖｄｃが上昇した場合（ステップＳ１のＹＥＳ）、主制御部２０は、第１実施形態と同じステップＳ２，Ｓ３の処理を実行する。この説明については省略する。 The control executed by the main control unit 20 will be described with reference to the flowchart of FIG. 4 and the time chart of FIG.
When the voltage Vdc of the smoothing capacitor 4 increases (YES in Step S1), the main control unit 20 executes the same processes of Steps S2 and S3 as in the first embodiment. This description is omitted.
　商用三相交流電源１に電圧低下が生じた場合、その電源電圧の低下に伴ってコンバータ２の出力電圧Ｖａも低下する。この場合、負荷であるブラシレスＤＣモータＭへの電力供給は続くため、平滑コンデンサ４の電圧Ｖｄｃが下降してコンバータ２の出力電圧Ｖａを下回る。 When a voltage drop occurs in the commercial three-phase AC power supply 1, the output voltage Va of the converter 2 also decreases as the power supply voltage decreases. In this case, since the power supply to the brushless DC motor M as a load continues, the voltage Vdc of the smoothing capacitor 4 decreases and falls below the output voltage Va of the converter 2.
　平滑コンデンサ４の電圧Ｖｄｃの下降時（ステップＳ１のＮＯ、ステップＳ４のＹＥＳ）、主制御部２０は、センサレス・ベクトル制御部５０におけるトルク成分電流Ｉｑに基づき、負荷の大きさを判定する（ステップＳ５）。 When the voltage Vdc of the smoothing capacitor 4 decreases (NO in Step S1, YES in Step S4), the main control unit 20 determines the magnitude of the load based on the torque component current Iq in the sensorless vector control unit 50 (Step S1). S5).
　負荷の大きさが軽負荷であると判定した場合（ステップＳ５のＹＥＳ）、主制御部２０は、平滑コンデンサ４の電圧Ｖｄｃと第１設定値Ｖ１´とを比較する（ステップＳ６）。平滑コンデンサ４の電圧Ｖｄｃが第１設定値Ｖ１´を下回ったとき（ステップＳ６のＹＥＳ）、主制御部２０は、リレー駆動信号Ｄを低レベルに設定してトランジスタ２２をオフし、これによりリレー３０を消勢（開動作）する（ステップＳ７）。リレー３０が消勢されると、リレー接点３０ａが開き、コンバータ２と平滑コンデンサ４との間の通電路に抵抗器３が投入された状態となる。続いて、主制御部２０は、後述の出力トルク低減を行っている場合はそれを解除する（ステップＳ１０）。 When it is determined that the load is a light load (YES in step S5), the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the first set value V1 ′ (step S6). When the voltage Vdc of the smoothing capacitor 4 falls below the first set value V1 ′ (YES in step S6), the main control unit 20 sets the relay drive signal D to a low level to turn off the transistor 22 and thereby the relay 30 is deactivated (opening operation) (step S7). When the relay 30 is de-energized, the relay contact 30a is opened, and the resistor 3 is put in the energization path between the converter 2 and the smoothing capacitor 4. Subsequently, the main control unit 20 cancels the output torque reduction described later (step S10).
　一方、平滑コンデンサ４の電圧Ｖｄｃの下降時、負荷の大きさが中負荷または重負荷である場合は、平滑コンデンサ４の電圧Ｖｄｃの下降速度が速くなる。 On the other hand, when the voltage Vdc of the smoothing capacitor 4 is lowered, if the load is a medium load or a heavy load, the falling speed of the voltage Vdc of the smoothing capacitor 4 is increased.
　主制御部２０は、平滑コンデンサ４の電圧Ｖｄｃの下降時（ステップＳ１のＮＯ、ステップＳ４のＹＥＳ）、かつ負荷の大きさが中負荷または重負荷であると判定した場合（ステップＳ５のＮＯ）、平滑コンデンサ４の電圧Ｖｄｃと第２設定値Ｖ２とを比較する（ステップＳ８）。そして、平滑コンデンサ４の電圧Ｖｄｃが第２設定値Ｖ２を下回ったとき（ステップＳ８のＹＥＳ）、主制御部２０は、負荷の大きさが所定値未満の軽負荷となるようにインバータ１０の出力トルクを低減する（ステップＳ９）。具体的には、主制御部２０は、負荷の大きさが所定値未満の軽負荷となるように、センサレス・ベクトル制御部５０におけるトルク成分電流Ｉｑを低減する。こうして、インバータ１０の出力トルクを低減することにより、電圧Ｖｄｃの下降速度が軽負荷時の下降速度に減少する。 When main controller 20 determines that voltage Vdc of smoothing capacitor 4 is decreasing (NO in step S1, YES in step S4), and determines that the load is medium load or heavy load (NO in step S5). The voltage Vdc of the smoothing capacitor 4 is compared with the second set value V2 (step S8). When the voltage Vdc of the smoothing capacitor 4 falls below the second set value V2 (YES in step S8), the main control unit 20 outputs the output of the inverter 10 so that the load becomes a light load that is less than a predetermined value. Torque is reduced (step S9). Specifically, the main control unit 20 reduces the torque component current Iq in the sensorless vector control unit 50 so that the load becomes a light load less than a predetermined value. Thus, by reducing the output torque of the inverter 10, the descending speed of the voltage Vdc is reduced to the descending speed at light load.
　主制御部２０は、トルク成分電流Ｉｑを低減した後、ステップＳ１の判定に戻る。電圧Ｖｄｃの下降が続いていれば（ステップＳ１のＮＯ、ステップＳ４のＹＥＳ）、主制御部２０は、負荷の大きさが軽負荷となったかとうかかを判定する（ステップＳ５）。 The main control unit 20 returns to the determination in step S1 after reducing the torque component current Iq. If the voltage Vdc continues to decrease (NO in step S1, YES in step S4), the main control unit 20 determines whether the load has become a light load (step S5).
　負荷の大きさが軽負荷に減少していれば（ステップＳ５のＹＥＳ）、主制御部２０は、平滑コンデンサ４の電圧Ｖｄｃと第１設定値Ｖ１´とを比較する（ステップＳ６）。そして、平滑コンデンサ４の電圧Ｖｄｃが第１設定値Ｖ１´を下回ったとき（ステップＳ６のＹＥＳ）、主制御部２０は、リレー駆動信号Ｄを低レベルに設定してトランジスタ２２をオフし、これによりリレー３０を消勢する（ステップＳ７）。リレー３０が消勢されると、リレー接点３０ａが開き、コンバータ２と平滑コンデンサ４との間の通電路に抵抗器３が投入された状態となる。そして、主制御部２０は、センサレス・ベクトル制御部５０におけるトルク成分電流Ｉｑの低減（出力トルク低減）を解除する（ステップＳ１０）
　以上のように、平滑コンデンサ４の電圧Ｖｄｃの下降時、かつ負荷の大きさが所定値未満の軽負荷時は、電圧Ｖｄｃが突入電流防止用の最小電圧値Ｖ１よりも高い第１設定値Ｖ１´を下回るタイミングでリレー３０を消勢するので、たとえリレー接点３０ａの開閉に時間遅れがあっても、突入電流を確実に防止できる。 If the magnitude of the load is reduced to a light load (YES in step S5), the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the first set value V1 ′ (step S6). When the voltage Vdc of the smoothing capacitor 4 falls below the first set value V1 ′ (YES in step S6), the main control unit 20 sets the relay drive signal D to a low level to turn off the transistor 22, Thus, the relay 30 is de-energized (step S7). When the relay 30 is de-energized, the relay contact 30a is opened, and the resistor 3 is put in the energization path between the converter 2 and the smoothing capacitor 4. Then, the main control unit 20 cancels the reduction of the torque component current Iq (output torque reduction) in the sensorless vector control unit 50 (step S10).
As described above, when the voltage Vdc of the smoothing capacitor 4 is lowered and the load is a light load with a magnitude less than a predetermined value, the voltage Vdc is higher than the minimum voltage value V1 for preventing inrush current. Since the relay 30 is deenergized at a timing lower than ', even if there is a time delay in opening and closing the relay contact 30a, an inrush current can be reliably prevented.
　負荷の大きさが所定値以上の中負荷時または重負荷時は、負荷の大きさが所定値未満の軽負荷となるようにインバータ１０の出力トルクを低減し、これにより電圧Ｖｄｃの下降速度を軽負荷時の下降速度まで減少させるので、電圧Ｖｄｃの下降を確実に捕らえることができる。すなわち、負荷の大きさに影響を受けることなく、突入電流を確実に防止できる。　
　他の効果は第１実施形態と同じである。 When the load size is medium load or heavy load greater than or equal to a predetermined value, the output torque of the inverter 10 is reduced so that the load size becomes a light load less than the predetermined value, thereby reducing the rate of decrease in the voltage Vdc. Since the speed is reduced to the lowering speed at light load, the lowering of the voltage Vdc can be reliably captured. That is, inrush current can be reliably prevented without being affected by the size of the load.
Other effects are the same as those of the first embodiment.
　［３］第３実施形態について説明する。　
　主制御部２０は、主要な機能として、次の（１１）～（１３）の手段を有する。　
　（１１）平滑コンデンサ４の電圧（電圧検出部２１の検出電圧）Ｖｄｃが第２設定値Ｖ２以上に上昇した場合に、リレー３０を閉動作させてリレー接点３０ａを閉じる第１制御手段。 [3] A third embodiment will be described.
The main control unit 20 has the following means (11) to (13) as main functions.
(11) First control means for closing the relay contact 30a by closing the relay 30 when the voltage of the smoothing capacitor 4 (detection voltage of the voltage detection unit 21) Vdc rises to the second set value V2 or more.
　（１２）平滑コンデンサ４の電圧Ｖｄｃが第１設定値Ｖ１´未満に下降した場合に、リレー３０を開動作させてリレー接点３０ａを開く第２制御手段。 (12) Second control means for opening the relay contact 30a by opening the relay 30 when the voltage Vdc of the smoothing capacitor 4 falls below the first set value V1 ′.
　（１３）平滑コンデンサ４の電圧Ｖｄｃが第２設定値Ｖ２未満に下降した場合にインバータ１０を回生モードで動作させ、この回生モードの動作によりインバータ１０の出力周波数Ｆが所定周波数である例えば許容最低運転周波数Ｆminに低下したとき、インバータ１０の回生モードの動作を終了し同インバータ１０の出力周波数Ｆが許容最低運転周波数Ｆminを保つようにインバータ１０の出力トルク（トルク成分電流Ｉｑ）を制御する第３制御手段。　
　他の構成は第１実施形態と同じである。 (13) When the voltage Vdc of the smoothing capacitor 4 falls below the second set value V2, the inverter 10 is operated in the regeneration mode, and the output frequency F of the inverter 10 is a predetermined frequency by the operation in the regeneration mode. When the operating frequency Fmin is lowered, the operation of the inverter 10 in the regenerative mode is terminated, and the output torque (torque component current Iq) of the inverter 10 is controlled so that the output frequency F of the inverter 10 maintains the allowable minimum operating frequency Fmin. 3 control means.
Other configurations are the same as those of the first embodiment.
　主制御部２０が実行する制御を図６のフローチャートおよび図７のタイムチャートを参照しながら説明する。　
　平滑コンデンサ４の電圧Ｖｄｃの上昇時（ステップＳ１のＹＥＳ）、主制御部２０は、後述する許容最低運転周波数Ｆminの保持を行っていればそれを解除し（ステップＳ１ａ）、かつ電圧Ｖｄｃと第２設定値Ｖ２とを比較する（ステップＳ２）。そして、電圧Ｖｄｃが第２設定値Ｖ２に達したとき（ステップＳ２のＹＥＳ）、主制御部２０は、突入電流の心配がなくなったとの判断の下に、リレー駆動信号Ｄを高レベルに設定してトランジスタ２２をオンし、これによりリレー３０を付勢（閉動作）する（ステップＳ３）。このリレー３０の付勢により、リレー接点３０ａが閉じて抵抗器３に対する短絡路が形成され、コンバータ２と平滑コンデンサ４との間の通電路から抵抗器３が切り離された状態となる。このステップＳ１～Ｓ３の処理の流れは、ステップＳ１ａの処理が加わっている点のみ第１および第２実施形態と異なる。 The control executed by the main control unit 20 will be described with reference to the flowchart of FIG. 6 and the time chart of FIG.
When the voltage Vdc of the smoothing capacitor 4 increases (YES in step S1), the main control unit 20 cancels the allowable minimum operating frequency Fmin described later (step S1a), and cancels the voltage Vdc and the second voltage Vdc. 2 The set value V2 is compared (step S2). When the voltage Vdc reaches the second set value V2 (YES in step S2), the main control unit 20 sets the relay drive signal D to a high level based on the determination that the inrush current has been eliminated. The transistor 22 is turned on, thereby energizing (closing operation) the relay 30 (step S3). By energizing the relay 30, the relay contact 30 a is closed to form a short circuit path for the resistor 3, and the resistor 3 is disconnected from the energization path between the converter 2 and the smoothing capacitor 4. The process flow of steps S1 to S3 is different from the first and second embodiments only in that the process of step S1a is added.
　商用三相交流電源１に電圧低下が生じた場合、それに伴ってコンバータ２の出力電圧Ｖａも低下する。この場合、負荷であるブラシレスＤＣモータＭへの電力供給は続くため、平滑コンデンサ４の電圧Ｖｄｃが下降してコンバータ２の出力電圧Ｖａを下回る。 When a voltage drop occurs in the commercial three-phase AC power source 1, the output voltage Va of the converter 2 is also lowered accordingly. In this case, since the power supply to the brushless DC motor M as a load continues, the voltage Vdc of the smoothing capacitor 4 decreases and falls below the output voltage Va of the converter 2.
　平滑コンデンサ４の電圧Ｖｄｃの下降時（ステップＳ１のＮＯ、ステップＳ４のＹＥＳ）、主制御部２０は、平滑コンデンサ４の電圧Ｖｄｃと第１設定値Ｖ１´とを比較する（ステップＳ１１）。 When the voltage Vdc of the smoothing capacitor 4 falls (NO in step S1, YES in step S4), the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the first set value V1 ′ (step S11).
　平滑コンデンサ４の電圧Ｖｄｃが第１設定値Ｖ１´未満でない場合（ステップＳ１１のＮＯ）、主制御部２０は、平滑コンデンサ４の電圧Ｖｄｃと第２設定値Ｖ２とを比較する（ステップＳ１２）。 When the voltage Vdc of the smoothing capacitor 4 is not less than the first set value V1 ′ (NO in step S11), the main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the second set value V2 (step S12).
　平滑コンデンサ４の電圧Ｖｄｃが第２設定値Ｖ２を下回った場合（ステップＳ１２のＹＥＳ）、主制御部２０は、センサレス・ベクトル制御部５０におけるトルク成分電流Ｉｑを負の値に設定し、これによりインバータ１０を回生モードで動作させる（ステップＳ１３）。インバータ１０が回生モードで動作すると、平滑コンデンサ４の電圧Ｖｄｃが上昇方向に転じるとともに、インバータ１０の出力周波数Ｆが徐々に低下していく。 When the voltage Vdc of the smoothing capacitor 4 falls below the second set value V2 (YES in step S12), the main control unit 20 sets the torque component current Iq in the sensorless vector control unit 50 to a negative value, thereby The inverter 10 is operated in the regeneration mode (step S13). When the inverter 10 operates in the regenerative mode, the voltage Vdc of the smoothing capacitor 4 turns upward and the output frequency F of the inverter 10 gradually decreases.
　インバータ１０の出力周波数Ｆが許容最低運転周波数Ｆminに低下したとき（ステップＳ１４のＹＥＳ）、主制御部２０は、トルク成分電流Ｉｑを正の値に戻してインバータ１０の回生モードの動作を終了するとともに（ステップＳ１５）、インバータ１０の出力周波数Ｆが許容最低運転周波数Ｆminを保つようにインバータ１０の出力トルク（トルク成分電流Ｉｑ）を制御する（ステップＳ１６）。そして、主制御部２０は、この出力トルク制御を継続しながらステップＳ１の処理に戻る。 When the output frequency F of the inverter 10 decreases to the allowable minimum operating frequency Fmin (YES in step S14), the main control unit 20 returns the torque component current Iq to a positive value and ends the operation of the inverter 10 in the regeneration mode. At the same time (step S15), the output torque (torque component current Iq) of the inverter 10 is controlled so that the output frequency F of the inverter 10 maintains the allowable minimum operating frequency Fmin (step S16). Then, the main control unit 20 returns to the process of step S1 while continuing this output torque control.
　インバータ１０の出力トルク制御を継続している状態で、平滑コンデンサ４の電圧Ｖｄｃが設定値Ｖ１´未満に下降した場合（ステップＳ１のＮＯ、ステップＳ４のＹＥＳ、ステップＳ１１のＹＥＳ）、主制御部２０は、リレー３０を消勢し（ステップＳ１７）、かつ出力周波数Ｆを許容最低運転周波数Ｆminに保つ制御（インバータ１０の出力トルク制御）を解除する（ステップＳ１８）。 When the voltage Vdc of the smoothing capacitor 4 falls below the set value V1 ′ while continuing the output torque control of the inverter 10 (NO in step S1, YES in step S4, YES in step S11), the main control unit 20 deactivates the relay 30 (step S17), and cancels the control for maintaining the output frequency F at the allowable minimum operating frequency Fmin (output torque control of the inverter 10) (step S18).
　以上のように、平滑コンデンサ４の電圧Ｖｄｃの下降時は、その電圧Ｖｄｃが突入電流防止用の最小電圧値Ｖ１よりも高い第１設定値Ｖ１´を下回るタイミングでリレー３０を消勢するので、たとえリレー接点３０ａの開閉に時間遅れがあっても、突入電流を確実に防止できる。 As described above, when the voltage Vdc of the smoothing capacitor 4 decreases, the relay 30 is de-energized at a timing when the voltage Vdc falls below the first set value V1 ′ that is higher than the minimum voltage value V1 for preventing inrush current. Even if there is a time delay in opening and closing the relay contact 30a, inrush current can be reliably prevented.
　しかも、平滑コンデンサ４の電圧Ｖｄｃの下降時は、その電圧Ｖｄｃが第１設定値Ｖ１´より高い第２規定値Ｖ２を下回るタイミングでインバータ１０を回生モードで動作させ、その回生エネルギによって平滑コンデンサ４の電圧Ｖｄｃを一旦上昇側に変化させるので、第１設定値Ｖ１´に基づく抵抗器３の投入をできるだけ遅くすることができる。これにより、抵抗器３における電力損失を少なくすることができる。設定値Ｖ０に基づくインバータ１０の停止もできるだけ回避することができる。　
　他の効果は第１実施形態と同じである。 In addition, when the voltage Vdc of the smoothing capacitor 4 is lowered, the inverter 10 is operated in the regeneration mode at a timing when the voltage Vdc falls below the second specified value V2 higher than the first set value V1 ′, and the smoothing capacitor 4 is generated by the regenerative energy. Since the voltage Vdc is once changed to the rising side, the introduction of the resistor 3 based on the first set value V1 ′ can be made as late as possible. Thereby, the power loss in the resistor 3 can be reduced. Stopping of the inverter 10 based on the set value V0 can be avoided as much as possible.
Other effects are the same as those of the first embodiment.
　［４］第４実施形態について説明する。　
　この実施形態では、ブラシレスＤＣモータＭの負荷の大きさを、平滑コンデンサ４の電圧Ｖｄｃの変動の大きさで判断する。 [4] A fourth embodiment will be described.
In this embodiment, the magnitude of the load of the brushless DC motor M is determined by the magnitude of the fluctuation of the voltage Vdc of the smoothing capacitor 4.
　主制御部２０は、主要な機能として、次の（２１）～（２４）の手段を有する。　
　（２１）商用三相交流電源１の安定時における平滑コンデンサ４の電圧を基準電圧として求め、この基準電圧と現時点における平滑コンデンサ４の電圧（電圧検出部２１の検出電圧）Ｖｄｃとの差を電圧変化量ΔＶｄｃとして求める演算手段。上記基準電圧として、例えば、平滑コンデンサ４の電圧Ｖｄｃの所定時間における平均値Ｖｄｃｘを求める。平均値Ｖｄｃｘは、電圧Ｖｄｃを長時間にわたり積分した値であり、例えば、時定数の大きいローパスフィルタ処理により求める。 The main control unit 20 has the following means (21) to (24) as main functions.
(21) The voltage of the smoothing capacitor 4 when the commercial three-phase AC power supply 1 is stable is obtained as a reference voltage, and the difference between the reference voltage and the voltage of the smoothing capacitor 4 (the detection voltage of the voltage detection unit 21) Vdc at this time Calculation means for obtaining the change amount ΔVdc. As the reference voltage, for example, an average value Vdcx of the voltage Vdc of the smoothing capacitor 4 over a predetermined time is obtained. The average value Vdcx is a value obtained by integrating the voltage Vdc over a long period of time, and is obtained by, for example, low-pass filter processing with a large time constant.
　（２２）上記電圧変化量ΔＶｄｃが所定量ΔＶｓ未満の場合に負荷の大きさが所定値未満の軽負荷であると判定し、上記電圧変化量ΔＶｄｃが所定量ΔＶｓ以上の場合に負荷の大きさが所定値以上の中負荷または重負荷であると判定する判定手段。 (22) When the voltage change amount ΔVdc is less than the predetermined amount ΔVs, it is determined that the load is a light load having a value less than the predetermined value, and when the voltage change amount ΔVdc is equal to or greater than the predetermined amount ΔVs, Determining means for determining that the load is a medium load or a heavy load exceeding a predetermined value.
　（２３）平滑コンデンサ４の電圧（電圧検出部２１の検出電圧）Ｖｄｃが第２設定値Ｖ２以上に上昇した場合に、リレー３０を閉動作させてリレー接点３０ａを閉じる第１制御手段。 (23) First control means for closing the relay contact 30a by closing the relay 30 when the voltage of the smoothing capacitor 4 (detection voltage of the voltage detection unit 21) Vdc rises to the second set value V2 or more.
　（２４）上記判定結果が軽負荷で且つ平滑コンデンサ４の電圧Ｖｄｃが第１設定値Ｖ１´（＜Ｖ２）未満に下降した場合に、リレー３０を開動作させてリレー接点３０ａを開く第２制御手段。 (24) Second control for opening the relay contact 30a by opening the relay 30 when the determination result is a light load and the voltage Vdc of the smoothing capacitor 4 falls below the first set value V1 ′ (<V2). means.
　（２５）上記判定結果が中負荷または重負荷で且つ平滑コンデンサ４の電圧Ｖｄｃが第２設定値Ｖ２未満に下降した場合に、リレー３０を開動作させてリレー接点３０ａを開く第３制御手段。　
　他の構成は第１実施形態と同じである。 (25) Third control means for opening the relay contact 30a by opening the relay 30 when the determination result is a medium load or a heavy load and the voltage Vdc of the smoothing capacitor 4 falls below the second set value V2.
Other configurations are the same as those of the first embodiment.
　主制御部２０が実行する制御を図８のフローチャートを参照しながら説明する。　
　主制御部２０は、平滑コンデンサ４の電圧Ｖｄｃの平均値Ｖｄｃｘを例えば時定数の大きいローパスフィルタ処理により逐次に求め、この平均値Ｖｄｃｘと現時点の平滑コンデンサ４の電圧Ｖｄｃとの差を電圧変化量ΔＶｄｃとして算出する（ステップＳ０）。 Control executed by the main control unit 20 will be described with reference to the flowchart of FIG.
The main control unit 20 sequentially obtains an average value Vdcx of the voltage Vdc of the smoothing capacitor 4 by, for example, a low-pass filter process having a large time constant, and calculates a difference between the average value Vdcx and the current voltage Vdc of the smoothing capacitor 4 as a voltage change amount. It calculates as (DELTA) Vdc (step S0).
　そして、主制御部２０は、平滑コンデンサ４の電圧Ｖｄｃの上昇時（ステップＳ１のＹＥＳ）、平滑コンデンサ４の電圧Ｖｄｃと規定値Ｖ２とを比較する（ステップＳ２）。平滑コンデンサ４の電圧Ｖｄｃが規定値Ｖ２に達したとき（ステップＳ２のＹＥＳ）、主制御部２０は、突入電流の心配がなくなったとの判断の下に、リレー駆動信号Ｄを高レベルに設定してトランジスタ２２をオンし、これによりリレー３０を付勢（閉動作）する（ステップＳ３）。この付勢により、リレー接点３０ａが閉じて抵抗器３に対する短絡路が形成され、コンバータ２と平滑コンデンサ４との間の通電路から抵抗器３が切り離された状態となる。 The main control unit 20 compares the voltage Vdc of the smoothing capacitor 4 with the specified value V2 when the voltage Vdc of the smoothing capacitor 4 increases (YES in Step S1) (Step S2). When the voltage Vdc of the smoothing capacitor 4 reaches the specified value V2 (YES in step S2), the main control unit 20 sets the relay drive signal D to a high level based on the determination that the inrush current has been eliminated. The transistor 22 is turned on, thereby energizing (closing operation) the relay 30 (step S3). By this energization, the relay contact 30 a is closed, a short circuit path for the resistor 3 is formed, and the resistor 3 is disconnected from the energization path between the converter 2 and the smoothing capacitor 4.
　主制御部２０は、平滑コンデンサ４の電圧Ｖｄｃの下降時（ステップＳ１のＮＯ、ステップＳ４のＹＥＳ）、上記求めた電圧変化量ΔＶｄｃと所定量ΔＶｓとを比較する（ステップＳ５ａ）。 When the voltage Vdc of the smoothing capacitor 4 decreases (NO in step S1, YES in step S4), the main control unit 20 compares the obtained voltage change amount ΔVdc with the predetermined amount ΔVs (step S5a).
　電圧変化量ΔＶｄｃが所定量ΔＶｓ未満と小さい場合（ステップＳ５ａのＹＥＳ）、主制御部２０は、負荷が所定値未満の軽負荷であるとの判断の下に、平滑コンデンサ４の電圧Ｖｄｃと第１設定値Ｖ１´とを比較する（ステップＳ６）。そして、平滑コンデンサ４の電圧Ｖｄｃが設定値Ｖ１´を下回ったとき（ステップＳ６のＹＥＳ）、主制御部２０は、リレー駆動信号Ｄを低レベルに設定してトランジスタ２２をオフし、これによりリレー３０を消勢する（ステップＳ７）。このリレー３０の消勢により、リレー接点３０ａが開き、抵抗器３が投入される。 When the voltage change amount ΔVdc is as small as less than the predetermined amount ΔVs (YES in step S5a), the main control unit 20 determines that the load is a light load less than the predetermined value and the voltage Vdc of the smoothing capacitor 4 1 set value V1 'is compared (step S6). When the voltage Vdc of the smoothing capacitor 4 falls below the set value V1 ′ (YES in step S6), the main control unit 20 sets the relay drive signal D to a low level to turn off the transistor 22 and thereby the relay 30 is deactivated (step S7). By deactivating the relay 30, the relay contact 30a is opened and the resistor 3 is turned on.
　電圧変化量ΔＶｄｃが所定量ΔＶｓ以上と大きい場合（ステップＳ５ａのＮＯ）、主制御部２０は、負荷が所定値以上の中負荷または重負荷であるとの判断の下に、平滑コンデンサ４の電圧Ｖｄｃと第２設定値Ｖ２とを比較する（ステップＳ８）。そして、平滑コンデンサ４の電圧Ｖｄｃが第２設定値Ｖ２を下回ったとき（ステップＳ８のＹＥＳ）、主制御部２０は、リレー駆動信号Ｄを低レベルに設定してトランジスタ２２をオフし、これによりリレー３０を消勢する（ステップＳ７）。このリレー３０の消勢により、リレー接点３０ａが開き、抵抗器３が投入される。 When the voltage change amount ΔVdc is as large as the predetermined amount ΔVs or more (NO in step S5a), the main control unit 20 determines the voltage of the smoothing capacitor 4 based on the determination that the load is a medium load or a heavy load greater than the predetermined value. Vdc and the second set value V2 are compared (step S8). When the voltage Vdc of the smoothing capacitor 4 falls below the second set value V2 (YES in step S8), the main control unit 20 sets the relay drive signal D to a low level and turns off the transistor 22, thereby The relay 30 is de-energized (step S7). By deactivating the relay 30, the relay contact 30a is opened and the resistor 3 is turned on.
　以上のように、平滑コンデンサ４の電圧Ｖｄｃの平均値Ｖｄｃｘを基準電圧として逐次に求め、この平均値Ｖｄｃｘと現時点の平滑コンデンサ４の電圧Ｖｄｃとの差を電圧変化量ΔＶｄｃとして求め、この電圧変化量ΔＶｄｃから負荷の大きさを判定し、軽負荷時は第１設定値Ｖ１´をリレー３０の消勢用として選択し、中負荷時または重負荷時は第１設定値Ｖ１´より高い第２設定値Ｖ２をリレー３０の消勢用として選択することにより、負荷の大きさに影響を受けることなく、突入電流を確実に防止できる。 As described above, the average value Vdcx of the voltage Vdc of the smoothing capacitor 4 is sequentially obtained as the reference voltage, and the difference between the average value Vdcx and the current voltage Vdc of the smoothing capacitor 4 is obtained as the voltage change amount ΔVdc. The magnitude of the load is determined from the amount ΔVdc, the first set value V1 ′ is selected for deactivation of the relay 30 at light load, and the second higher than the first set value V1 ′ at medium load or heavy load. By selecting the set value V2 for de-energizing the relay 30, an inrush current can be reliably prevented without being affected by the magnitude of the load.
　他の効果は第１実施形態と同じである。なお、この第４実施形態では、平滑コンデンサ４の電圧Ｖｄｃの平均値Ｖｄｃｘを基準電圧として用いたが、電源電圧低下等の変動が生じる所定時間前の電圧Ｖｄｃを記憶しておきそれを基準電圧として用いてもよい。 Other effects are the same as in the first embodiment. In the fourth embodiment, the average value Vdcx of the voltage Vdc of the smoothing capacitor 4 is used as the reference voltage. However, the voltage Vdc before a predetermined time in which a fluctuation such as a drop in the power supply voltage occurs is stored and used as the reference voltage. It may be used as
　［５］変形例　
　上記各実施形態では、下降時の電圧Ｖｄｃに対するリレー消勢用の第２設定値として、上昇時の電圧Ｖｄｃに対するリレー付勢用の規定値Ｖ２をそのまま用いたが、第２設定値についてはこれに限定されるものではない。すなわち、第２設定値は、設定値Ｖ１´よりも高い値であればよく、またリレー３０の開閉の時間遅れやインバータ１０の消費電力量に応じて適宜に定めればよい。 [5] Modification
In each of the above embodiments, the specified value V2 for relay energization for the rising voltage Vdc is used as it is as the second setting value for relay de-energization for the falling voltage Vdc. It is not limited to. That is, the second set value may be a value higher than the set value V1 ′, and may be determined as appropriate according to the time delay of opening and closing of the relay 30 and the power consumption of the inverter 10.
　その他、上記各実施形態および変形例は、例として提示したものであり、発明の範囲を限定することは意図していない。この新規な実施形態および変形例は、その他の様々な形態で実施されることが可能であり、発明の要旨を逸脱しない範囲で、種々の省略、書き換え、変更を行うことができる。これら実施形態や変形は、発明の範囲は要旨に含まれるとともに、特許請求の範囲に記載された発明とその均等の範囲に含まれる。 Other than the above, the above embodiments and modifications are presented as examples, and are not intended to limit the scope of the invention. The novel embodiments and modifications can be implemented in various other forms, and various omissions, rewrites, and changes can be made without departing from the spirit of the invention. In these embodiments and modifications, the scope of the invention is included in the gist, and is included in the invention described in the claims and the equivalents thereof.
　１…商用三相交流電源、２…コンバータ、３…突入電流防止用の抵抗器、４…室平滑コンデンサ、１０…インバータ、Ｍ…ブラシレスＤＣモータ（負荷）、１１，１２，１３…電流センサ、２０…主制御部、２１…電圧検出部、２２…ＮＰＮ型トランジスタ、３０…リレー、３０ａ…リレー接点、５０…センサレス・ベクトル制御部 DESCRIPTION OF SYMBOLS 1 ... Commercial three-phase alternating current power supply, 2 ... Converter, 3 ... Resistor for inrush current prevention, 4 ... Room smoothing capacitor, 10 ... Inverter, M ... Brushless DC motor (load), 11, 12, 13 ... Current sensor, DESCRIPTION OF SYMBOLS 20 ... Main control part, 21 ... Voltage detection part, 22 ... NPN type transistor, 30 ... Relay, 30a ... Relay contact, 50 ... Sensorless vector control part

Claims (6)

  1. 　商用交流電源の電圧を直流に変換するコンバータと、
    　前記コンバータの出力端に接続された平滑コンデンサと、
    　前記平滑コンデンサの電圧を交流電圧に変換し、その交流電圧を負荷への駆動電力として出力するインバータと、
    　前記コンバータと前記平滑コンデンサとの間の通電路に配置された突入電流防止用の抵抗器と、
    　前記抵抗器に並列接続された接点を有するリレーと、
    　前記平滑コンデンサの電圧が規定値以上に上昇した場合に前記リレーを閉動作させ、前記平滑コンデンサの電圧が設定値未満に下降した場合に前記リレーを開動作させる制御手段と、
    　を備え、
    　前記設定値は、前記コンバータに流れる電流が同コンバータの許容最大電流を超えないために必要な前記平滑コンデンサの最小電圧値より高い
    　ことを特徴とする電力変換装置。     A converter that converts the voltage of the commercial AC power source into DC,
    A smoothing capacitor connected to the output of the converter;
    An inverter that converts the voltage of the smoothing capacitor into an AC voltage and outputs the AC voltage as drive power to a load;
    A resistor for preventing an inrush current disposed in a current path between the converter and the smoothing capacitor;
    A relay having contacts connected in parallel to the resistor;
    Control means for closing the relay when the voltage of the smoothing capacitor rises above a specified value, and opening the relay when the voltage of the smoothing capacitor drops below a set value;
    With
    The power converter according to claim 1, wherein the set value is higher than a minimum voltage value of the smoothing capacitor required so that a current flowing through the converter does not exceed an allowable maximum current of the converter.
  2. 　前記設定値は、前記規定値以下であって、前記コンバータに流れる電流が同コンバータの許容最大電流を超えないために必要な前記平滑コンデンサの最小電圧値より所定値高い第１設定値、およびその第１設定値より高い第２設定値を含む
    　ことを特徴とする請求項１記載の電力変換装置。     The set value is equal to or less than the specified value, and is a first set value that is higher by a predetermined value than the minimum voltage value of the smoothing capacitor necessary for the current flowing through the converter not to exceed the maximum allowable current of the converter, and The power conversion device according to claim 1, further comprising a second set value higher than the first set value.
  3. 　前記制御手段は、
    　前記平滑コンデンサの電圧が前記規定値以上に上昇した場合に、前記リレーを閉動作させ、
    　前記負荷の大きさが所定未満で且つ前記平滑コンデンサの電圧が前記第１設定値未満に下降した場合に、前記リレーを開動作させ、
    　前記負荷の大きさが所定以上で且つ前記平滑コンデンサの電圧が前記第２設定値未満に下降した場合に、前記リレーを開動作させる
    　ことを特徴とする請求項２記載の電力変換装置。     The control means includes
    When the voltage of the smoothing capacitor rises above the specified value, the relay is closed,
    When the magnitude of the load is less than a predetermined value and the voltage of the smoothing capacitor falls below the first set value, the relay is opened.
    The power converter according to claim 2, wherein when the magnitude of the load is equal to or larger than a predetermined value and the voltage of the smoothing capacitor falls below the second set value, the relay is opened.
  4. 　前記制御手段は、
    　前記平滑コンデンサの電圧が前記規定値以上に上昇した場合に、前記リレーを閉動作させ、
    　前記負荷の大きさが所定未満で且つ前記平滑コンデンサの電圧が前記第１設定値未満に下降した場合に、前記リレーを開動作させ、
    　前記負荷の大きさが所定以上で且つ前記平滑コンデンサの電圧が前記第２設定値未満に下降した場合に、前記インバータの出力トルクを低減する
    　ことを特徴とする請求項２記載の電力変換装置。     The control means includes
    When the voltage of the smoothing capacitor rises above the specified value, the relay is closed,
    When the magnitude of the load is less than a predetermined value and the voltage of the smoothing capacitor falls below the first set value, the relay is opened.
    The power converter according to claim 2, wherein the output torque of the inverter is reduced when the magnitude of the load is equal to or greater than a predetermined value and the voltage of the smoothing capacitor falls below the second set value.
  5. 　前記制御手段は、
    　前記平滑コンデンサの電圧が前記規定値以上に上昇した場合に、前記リレーを閉動作させ、
    　前記平滑コンデンサの電圧が前記第２設定値未満に下降した場合に前記インバータを回生モードで動作させ、この回生モードの動作により前記インバータの出力周波数が所定周波数に低下した場合に、前記インバータの回生モードの動作を終了し同インバータの出力周波数が前記所定周波数を保つように同インバータの出力トルクを制御し、
    　前記平滑コンデンサの電圧が前記第１設定値未満に下降した場合に、前記リレーを開動作させるとともに、前記出力トルクの制御を解除する
    　ことを特徴とする請求項２記載の電力変換装置。     The control means includes
    When the voltage of the smoothing capacitor rises above the specified value, the relay is closed,
    The inverter is operated in a regeneration mode when the voltage of the smoothing capacitor falls below the second set value, and when the output frequency of the inverter is lowered to a predetermined frequency due to the operation in the regeneration mode, the regeneration of the inverter is performed. Control the output torque of the inverter so that the operation of the mode ends and the output frequency of the inverter maintains the predetermined frequency,
    The power converter according to claim 2, wherein when the voltage of the smoothing capacitor falls below the first set value, the relay is opened and the control of the output torque is released.
  6. 　前記制御手段は、
    　前記商用交流電源の安定時における前記平滑コンデンサの電圧を基準電圧として求め、この基準電圧と現時点における平滑コンデンサの電圧との差を電圧変化量として求め、
    　前記電圧変化量が所定量未満の場合に、前記負荷の大きさが所定値未満であると判定し、
    　前記電圧変化量が所定量以上の場合に、前記負荷の大きさが所定値以上であると判定する
    　ことを特徴とする請求項３または請求項４記載の電力変換装置。     The control means includes
    Obtain the voltage of the smoothing capacitor at the time of stabilization of the commercial AC power supply as a reference voltage, obtain the difference between the reference voltage and the voltage of the smoothing capacitor at the present time as a voltage change amount,
    When the voltage change amount is less than a predetermined amount, it is determined that the size of the load is less than a predetermined value,
    The power converter according to claim 3 or 4, wherein when the voltage change amount is equal to or greater than a predetermined amount, the load is determined to be greater than or equal to a predetermined value.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018014813A (en) * 2016-07-20 2018-01-25 東芝シュネデール・インバータ株式会社 Inverter device
EP3379712A4 (en) * 2015-11-18 2019-07-10 Hitachi Industrial Equipment Systems Co., Ltd. Power conversion device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110098722B (en) * 2019-05-06 2021-04-13 阳光电源股份有限公司 Switching method, device and system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62196072A (en) * 1986-02-21 1987-08-29 Mitsubishi Electric Corp Rush-current limitting circuit for inverter
JPS63124766A (en) * 1986-11-13 1988-05-28 Matsushita Electric Ind Co Ltd Rush current limiting circuit
JPS63262026A (en) * 1987-04-16 1988-10-28 日本電気株式会社 Ac-dc switching source input voltage monitoring circuit
JP2012147548A (en) * 2011-01-11 2012-08-02 Konica Minolta Business Technologies Inc Power supply device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62196072A (en) * 1986-02-21 1987-08-29 Mitsubishi Electric Corp Rush-current limitting circuit for inverter
JPS63124766A (en) * 1986-11-13 1988-05-28 Matsushita Electric Ind Co Ltd Rush current limiting circuit
JPS63262026A (en) * 1987-04-16 1988-10-28 日本電気株式会社 Ac-dc switching source input voltage monitoring circuit
JP2012147548A (en) * 2011-01-11 2012-08-02 Konica Minolta Business Technologies Inc Power supply device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3379712A4 (en) * 2015-11-18 2019-07-10 Hitachi Industrial Equipment Systems Co., Ltd. Power conversion device
JP2018014813A (en) * 2016-07-20 2018-01-25 東芝シュネデール・インバータ株式会社 Inverter device

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