WO2018043258A1 - Power conversion device and air conditioner equipped with same - Google Patents

Power conversion device and air conditioner equipped with same Download PDF

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Publication number
WO2018043258A1
WO2018043258A1 PCT/JP2017/030195 JP2017030195W WO2018043258A1 WO 2018043258 A1 WO2018043258 A1 WO 2018043258A1 JP 2017030195 W JP2017030195 W JP 2017030195W WO 2018043258 A1 WO2018043258 A1 WO 2018043258A1
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Prior art keywords
motor
state
switching elements
control unit
lower arm
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PCT/JP2017/030195
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French (fr)
Japanese (ja)
Inventor
渉 初瀬
正博 田村
勇紀 江幡
Original Assignee
日立ジョンソンコントロールズ空調株式会社
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Publication of WO2018043258A1 publication Critical patent/WO2018043258A1/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
    • H02M7/42—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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P3/00—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters
    • H02P3/06—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter

Definitions

  • the present invention relates to a power conversion device and the like.
  • An air conditioner in which a check valve is provided on the suction side or discharge side of a scroll compressor is known.
  • a check valve By providing such a check valve, after the motor for driving the compressor stops, the reverse rotation of the motor due to the differential pressure on the discharge side and the suction side of the compressor is prevented, and the noise and vibration are suppressed. I have to.
  • Patent Document 1 describes preventing reverse rotation after stopping the operation of the compressor motor by energizing all switching elements on the positive voltage side or the negative voltage side of the inverter device.
  • Patent Document 2 discloses a DC brushless motor by simultaneously bringing a first switching element group connected to a positive electrode of a DC power supply or a second switching element group connected to a negative electrode of a DC power supply into a conductive state. It is described that the reverse rotation after the operation stop is prevented.
  • JP 2000-287485 A Japanese Patent Laid-Open No. 11-46494
  • an object of the present invention is to provide a highly reliable power conversion device and the like.
  • the present invention provides a first state in which at least two switching elements of one of the upper arm and the lower arm are turned on and the other switching element is turned off when the motor is stopped. And a second state in which the switching elements of the upper arm and the lower arm are turned off alternately.
  • the present invention also provides a first control for controlling the switching elements of the upper arm and the lower arm so as to electrically connect the motor winding and the DC power source when the motor is stopped, and the switching of the upper arm and the lower arm.
  • the second control for turning off the element is alternately repeated.
  • a highly reliable power conversion device or the like can be provided.
  • FIG. 1 It is a block diagram of an air conditioner provided with the power converter device which concerns on 1st Embodiment of this invention. It is a block diagram containing the power converter device which concerns on 1st Embodiment of this invention. It is a flowchart of the process which the control part of the power converter device which concerns on 1st Embodiment of this invention performs. It is explanatory drawing regarding the power converter device which concerns on 1st Embodiment of this invention, (a) is explanatory drawing which shows "the 1st state" of a power converter device, (b) is "2nd of a power converter device.
  • (A) is explanatory drawing of the on-duty command signal in the switching element of a lower arm
  • (b) is explanatory drawing of the pulse signal which shows ON / OFF of the switching element of a lower arm.
  • (A) is explanatory drawing of the other example regarding the command signal of on-duty in the switching element of a lower arm
  • (b) is explanatory drawing of the pulse signal which shows ON / OFF of the switching element of a lower arm. It is an experimental result which shows the rotation speed of a compressor, the torque of a motor, and the change of the electric current which flows into a motor in an air conditioner provided with the power converter device which concerns on 1st Embodiment of this invention.
  • FIG. 1 is a configuration diagram of an air conditioner 100 including a power conversion device 30 according to the first embodiment.
  • the air conditioner 100 is a device that performs air conditioning (cooling operation, heating operation, dehumidifying operation, etc.) by circulating a refrigerant in a heat pump cycle.
  • the air conditioner 100 includes a refrigerant circuit 10, an outdoor fan F1, and an indoor fan F2.
  • the air conditioner 100 includes a converter unit 20 and a power conversion device 30.
  • a smoothing capacitor C is included in the electrical system. It has.
  • the refrigerant circuit 10 is a circuit in which a compressor 11, an outdoor heat exchanger 12, an expansion valve 13, and an indoor heat exchanger 14 are sequentially connected in an annular manner via a four-way valve 15.
  • the compressor 11 is a device that compresses a gaseous refrigerant and includes a motor 11a as a drive source.
  • the compressor 11 is, for example, a scroll-type compressor, and has a characteristic that a differential pressure is generated on the suction side and the discharge side when the compressor 11 is stopped. If the motor 11a reversely rotates at a high speed due to the above-described differential pressure, transient current fluctuations and torque fluctuations occur due to the induced voltage. On the other hand, if a check valve (not shown) for restricting the reverse rotation of the motor 11a is provided, the number of parts increases and the cost increases. Therefore, in this embodiment, as an example, the compressor 11 is not provided with a check valve, and the reverse rotation of the motor 11 a is suppressed by the control of the power converter 30.
  • the four-way valve 15 is a valve that switches the flow direction of the refrigerant. That is, during the cooling operation (broken line arrow in FIG. 1), the four-way valve 15 is controlled so that the outdoor heat exchanger 12 functions as a condenser and the indoor heat exchanger 14 functions as an evaporator. On the other hand, during the heating operation (solid arrow in FIG. 1), the four-way valve 15 is controlled so that the indoor heat exchanger 14 functions as a condenser and the outdoor heat exchanger 12 functions as an evaporator.
  • the refrigerant circuit 10 includes a compressor 11, a condenser (one of the outdoor heat exchanger 12 and the indoor heat exchanger 14), an expansion valve 13, and an evaporator (the outdoor heat exchanger 12 and the indoor heat exchanger 14). And the other) are sequentially connected in an annular manner via a four-way valve 15.
  • the outdoor heat exchanger 12 is a heat exchanger that exchanges heat between outside air and refrigerant.
  • the outdoor fan F ⁇ b> 1 is a fan that sends outside air to the outdoor heat exchanger 12, and is installed in the vicinity of the outdoor heat exchanger 12.
  • the indoor heat exchanger 14 is a heat exchanger in which heat is exchanged between room air (air in the air-conditioning target space) and the refrigerant.
  • the indoor fan F ⁇ b> 2 is a fan that sends room air into the indoor heat exchanger 14, and is installed near the indoor heat exchanger 14.
  • the expansion valve 13 is a valve that depressurizes the refrigerant condensed in the “condenser”.
  • the refrigerant decompressed by the expansion valve 13 is guided to the “evaporator” described above.
  • each apparatus of the air conditioner 100 is controlled based on the detection value of various sensors (not shown), the operation signal from a remote control (not shown), etc.
  • the converter unit 20 is a power converter that converts an AC voltage applied from the AC power source E into a DC voltage.
  • the converter unit 20 also has a function of adjusting the height of the DC voltage described above.
  • the power converter 30 is a device that converts a predetermined DC voltage into a driving voltage (that is, a three-phase AC voltage) of the motor 11a.
  • FIG. 2 is a configuration diagram including the power conversion device 30.
  • the smoothing capacitor C shown in FIG. 2 is a capacitor that smoothes the voltage (DC voltage including pulsating current) applied from the converter unit 20, and the positive side and the negative side are connected to the converter unit 20.
  • the power conversion device 30 includes a power conversion unit 31, a current detection unit 32, and a control unit 33.
  • the power conversion unit 31 is an inverter circuit that converts a DC voltage applied from a “DC power supply” into a drive voltage of the motor 11a.
  • the “DC power supply” described above includes an AC power supply E, a converter unit 20 and a smoothing capacitor C.
  • the power conversion unit 31 includes a bridge circuit 31a and a gate driver 31b.
  • the bridge circuit 31a includes upper arm switching elements S1, S3, S5 connected to the positive side of the smoothing capacitor C (DC power supply) and a lower arm switching element connected to the negative side of the smoothing capacitor C (DC power supply). S2, S4, and S6.
  • a free-wheeling diode D is connected to the switching elements S1 to S6 in antiparallel.
  • the switching elements S1 to S6 are, for example, MOSFETs (Metal-Oxide-Semiconductor-Field-Effect-Transistors), and are switched on / off by a command from the control unit 33.
  • MOSFETs Metal-Oxide-Semiconductor-Field-Effect-Transistors
  • IGBT Insulated Gate Bipolar Transistor
  • the connection point between the switching element S1 whose drain is connected to the positive side of the smoothing capacitor C and the switching element S2 whose source is connected to the negative side of the smoothing capacitor C is a W-phase wiring.
  • the current capacities of the switching elements S1 to S6 are preferably equal to or greater than a predetermined demagnetization current value (current value at which demagnetization starts in the permanent magnet of the motor 11a). This is because even if a large current close to the demagnetizing current value flows through the switching elements S1 to S6, it is possible to prevent the problems of the switching elements S1 to S6.
  • the gate driver 31b has a function of applying a predetermined voltage (that is, outputting a gate signal) to the gates of the switching elements S1 to S6 based on the pulse signal input from the pulse control unit 33b.
  • the current detector 32 detects the current flowing through the windings gu, gv, and gw of the motor 11a, and is installed in the U-phase, V-phase, and W-phase wirings in the example shown in FIG.
  • the detection value of the current detection unit 32 is output to an inverter control unit 33a described later.
  • the control unit 33 has a function of controlling on / off of the switching elements S1 to S6 based on detection values of currents flowing through the windings gu, gv, and gw of the motor 11a.
  • the control unit 33 includes electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces. Then, the program stored in the ROM is read out and expanded in the RAM, and the CPU executes various processes.
  • a CPU Central Processing Unit
  • ROM Read Only Memory
  • RAM Random Access Memory
  • the control unit 33 includes an inverter control unit 33a and a pulse control unit 33b.
  • the inverter control unit 33a is configured to apply a predetermined applied voltage command (three-phase AC applied to the windings gu, gv, gw) to the pulse control unit 33b based on the detected value of the current flowing in the windings gu, gv, gw of the motor 11a. (Command value of voltage) is output.
  • the pulse control unit 33b has a function of generating a predetermined pulse signal by PWM control (Pulse Width Modulation) based on the applied voltage command input from the inverter control unit 33a.
  • the pulse signal generated by the pulse controller 33b is output to the gate driver 31b as described above.
  • the control unit 33 also has a function of controlling the boosting operation of the converter unit 20.
  • FIG. 3 is a flowchart of processing executed by the control unit 33 of the power conversion device 30.
  • the control unit 33 determines whether to stop the motor 11a. That is, the control unit 33 determines whether or not a command for stopping the air-conditioning operation or thermo-off is input to itself.
  • step S101 When the motor 11a is not stopped in step S101 (S101: No), the control unit 33 repeats the determination process of step S101 while driving the motor 11a. On the other hand, when stopping the motor 11a in step S101 (S101: Yes), the process of the control part 33 progresses to step S102.
  • step S102 the control unit 33 stops the boosting operation of the converter unit 20.
  • the windings gu, gv, gw of the motor 11a and the smoothing capacitor C are electrically disconnected, and no energy is output from the converter unit 20 to the motor 11a. Become.
  • the control unit 33 stops the boosting operation of the converter unit 20 before performing the control of step S103.
  • the smoothing capacitor C can be protected, and the voltage applied to the gate driver 31b can be suppressed within a predetermined allowable range.
  • step S103 the control unit 33 alternately repeats the “first state” and the “second state”.
  • the “first state” of step S103 will be described with reference to FIG. 4A, and further, the “second state” will be described with reference to FIG. ) Will be described.
  • FIG. 4A is an explanatory diagram showing a “first state” of the power conversion device 30.
  • the control unit 33 turns on the switching elements S2, S4, S6 of the lower arm and turns off the switching elements S1, S3, S5 of the upper arm.
  • an induced voltage (back electromotive force) that prevents the reverse rotation is generated in the windings gu, gv, and gw.
  • a current flows through the switching elements S2, S4, S6 and the windings gu, gv, gw so as to prevent reverse rotation of the motor 11a.
  • the reverse rotation of the motor 11a due to the differential pressure between the suction side and the discharge side of the compressor 11 is suppressed.
  • FIG. 4B is an explanatory diagram showing a “second state” of the power conversion device 30.
  • the control unit 33 turns off the switching elements S1, S3, and S5 of the upper arm and the switching elements S2, S4, and S6 of the lower arm. If it does so, the recirculation
  • the “second state” in which all of the switching elements S1 to S6 are turned off is compared to the “first state” in which the switching elements S2, S4, S6 of the lower arm are turned on and short-circuited.
  • the amplitude of the current flowing through the lines gu, gv, gw is reduced. Therefore, current fluctuation and torque fluctuation in the motor 11a can be suppressed while suppressing reverse rotation of the motor 11a.
  • FIG. 5A is an explanatory diagram of an on-duty command signal in the switching elements S2, S4, and S6 of the lower arm.
  • the horizontal axis of Fig.5 (a) is the time which passed since the drive stop of the motor 11a.
  • the vertical axis in FIG. 5A is a command signal indicating the on-duty of the switching elements S2, S4, S6 of the lower arm.
  • the monotonously increasing command signal (solid line) that gradually approaches the value “1” in FIG. 5A is generated by, for example, inputting a step function to a well-known first-order lag filter (not shown). This command signal is generated in the inverter control unit 33a (see FIG. 2) and output to the pulse control unit 33b (see FIG. 2).
  • control unit 33 increases the on-duty of the switching elements S2, S4, and S6 of the lower arm in the process of alternately repeating the “first state” and the “second state” (S103). If the ON state (short circuit state) of the switching elements S2, S4, S6 of the lower arm is continued immediately after the motor 11a is stopped, the induced voltage due to the reverse rotation of the motor 11a fluctuates rapidly, causing a transient current. Variation and torque variation may occur.
  • the control unit 33 gradually increases the on-duty of the switching elements S2, S4, and S6 of the lower arm. As a result, transient current fluctuations and torque fluctuations immediately after the motor 11a is stopped can be suppressed. That is, immediately after the drive of the motor 11a is stopped, the control unit 33 gradually applies the brake torque to the reverse rotation of the motor 11a, and then gradually increases the brake torque.
  • FIG. 5B is an explanatory diagram of a pulse signal indicating ON / OFF of the switching elements S2, S4, and S6 of the lower arm.
  • the horizontal axis of FIG.5 (b) is time and respond
  • the vertical axis in FIG. 5B is a pulse signal indicating ON / OFF of the switching elements S2, S4, S6 of the lower arm.
  • the pulse signal indicating “1” is sent from the pulse control unit 33b (see FIG. 2) to the gate driver 31b. (See FIG. 2).
  • the lower arm switching elements S2, S4, and S6 are turned on.
  • a pulse signal indicating “0” is sent from the pulse control unit 33b (see FIG. 2) to the gate driver 31b. (See FIG. 2).
  • the lower arm switching elements S2, S4, and S6 are turned off.
  • step S103 of FIG. 3 the on / off of the switching elements S2, S4, S6 of the lower arm is alternately switched.
  • the upper arm switching elements S1, S3, and S5 are omitted in FIGS. 5A and 5B, but are always in the OFF state during the process of step S103 (FIGS. 4A and 4B). b)).
  • FIG. 6A is an explanatory diagram of another example regarding the on-duty command signal in the switching elements S2, S4, S6 of the lower arm
  • FIG. 6B is a switching element S2, S4, S6 of the lower arm. It is explanatory drawing of the pulse signal which shows ON / OFF of.
  • the on-duty of the lower-arm switching elements S2, S4, S6 in step S103 may be monotonously increased, and the on-duty command signal may be increased linearly as shown in FIG. Then, based on the command signal shown in FIG. 6A, the pulse signal shown in FIG. 6B is generated.
  • step S104 the control unit 33 determines whether or not a predetermined time ts (see FIGS. 5 and 6) has elapsed since the start of the control in step S103.
  • the predetermined time ts (for example, several seconds to several tens of seconds) is the following before the off time of the switching elements S2, S4, S6 of the lower arm becomes equal to or less than the lower limit of the off time during which the gate driver 31b can operate.
  • the process of step S105 is set to be performed. As a result, malfunction of the gate driver 31b can be prevented, and reverse rotation of the motor 11a can be appropriately suppressed.
  • step S104 If the predetermined time ts has not elapsed since the start of the control in step S103 (S104: No), the process of the control unit 33 returns to step S103. On the other hand, when the predetermined time ts has elapsed since the start of the control in step S103 (S104: Yes), the process of the control unit 33 proceeds to step S105.
  • step S105 the control unit 33 continues the “first state”.
  • the control unit 33 continues the first state after performing the control for alternately repeating the “first state” and the “second state” for a predetermined time ts (S103, S104: Yes) ( S105).
  • the gate driver 31b can be prevented from malfunctioning, and the time required to stop the reverse rotation of the motor 11a can be shortened.
  • control unit 33 After performing the process of step S105, the control unit 33 ends the series of processes (END). Although omitted in FIG. 3, the control unit 33 performs the operation of continuing the “first state” for a predetermined time in step S105, and then turns off the switching elements S1 to S6.
  • the control unit 33 sets the “first state” (see FIG. 4A) and the “second state” (see FIG. 4B). , Are repeated alternately. Thereby, transient current fluctuations and torque fluctuations in the motor 11a can be suppressed.
  • FIG. 11 shows the rotational speed of the compressor 11 in the comparative example (see FIG. 11A), the torque of the motor 11a and the like (see FIG. 11B), and the current flowing in the motor 11a (see FIG. 11C). It is an experimental result which shows the change of.
  • the horizontal axis (time) of FIG. 11 (a), (b), (c) is the time which passed since the drive stop of the motor 11a.
  • the upper arm switching elements S1, S3, and S5 are maintained in the off state, and the lower arm switching elements S2, S4, and S6 are maintained in the on state. That is, in the comparative example, the “first state” (see FIG. 4A) is continued without switching the switching elements S1 to S6 to the “second state” (see FIG. 4B). ing.
  • the motor 11a starts to reversely rotate at the rotational speed of the value ⁇ 1 due to the differential pressure on the suction side and the discharge side of the compressor 11, and then The rotation speed is monotonically decreasing to zero.
  • the current flowing through the windings gu, gv, and gw greatly fluctuates, and the amplitude exceeds a predetermined value I1.
  • the predetermined value I1 is, for example, a current value at which demagnetization starts to occur in a permanent magnet (not shown) of the motor 11a.
  • the current greatly fluctuates because the induced voltage abruptly fluctuates due to the reverse rotation of the motor 11a and the accompanying current is maintained in the ON state. This is because it flows through S2, S4 and S6.
  • a large current flows through the motor 11a and the switching elements S2, S4, and S6 as described above, there is a possibility that demagnetization of a permanent magnet (not shown) provided in the motor 11a and problems of the switching elements S2, S4, and S6 are caused. is there.
  • the torque greatly fluctuates immediately after the motor 11a is stopped due to the above-described current fluctuation.
  • the torque of the motor 11a fluctuates greatly, a roaring sound or vibration may be generated, which may cause discomfort to the user.
  • FIG. 7 shows the rotational speed of the compressor 11 (see FIG. 7A), the torque of the motor 11a and the like (see FIG. 7B), and the current flowing through the motor 11a (FIG. 7C).
  • FIG. 7C shows the change of reference.
  • the amplitude of the current flowing through the motor 11a is suppressed to less than the predetermined value I1. (See FIG. 7C).
  • the switching elements S1 to S6 are turned off, fluctuations in the induced voltage generated in the windings gu, gv, and gw are suppressed. Therefore, according to the present embodiment, it is possible to suppress reverse rotation after the motor 11a is stopped while preventing demagnetization of a permanent magnet (not shown) included in the motor 11a and occurrence of defects in the switching elements S1 to S6. .
  • the amplitude of the current flowing through the motor 11a is relatively small (see FIG. 7C)
  • the fluctuation range of the torque of the motor 11a immediately after the stop of the motor 11a is shown as a comparative example ( It is smaller than that shown in FIG. Therefore, according to the present embodiment, it is possible to suppress the roaring sound and vibration caused by the torque fluctuation of the motor 11a.
  • FIG. 8 is an explanatory diagram showing the operating efficiency of the compressor 11 in the first embodiment and the comparative example.
  • the horizontal axis of FIG. 8 is the rotational speed of the motor 11a, and the vertical axis is the operating efficiency of the compressor 11.
  • the comparative example (broken line) is an air conditioner having a configuration in which a check valve (not shown) that restricts reverse rotation of the motor 11a is provided in the compressor 11.
  • the operation efficiency of the compressor 11 is higher in the present embodiment than in the comparative example in the entire range of the rotational speeds N1 to N2 that is the operation region of the compressor 11. This is because the pressure loss of the refrigerant in the compressor 11 is smaller in the present embodiment in which a check valve (not shown) is not provided. Moreover, according to this embodiment, since it is not necessary to provide a check valve, the number of parts of the compressor 11 can be reduced, and thus the manufacturing cost of the air conditioner 100 can be reduced.
  • Second Embodiment is different from the first embodiment in how the switching elements S1 to S6 are switched on and off when the compressor 11 is stopped, but the other (the air conditioner 100 and the power conversion device 30).
  • the configuration (see FIGS. 1 and 2) is the same as in the first embodiment. Therefore, a different part from 1st Embodiment is demonstrated and description is abbreviate
  • FIG. 9 is a flowchart of processing executed by the control unit 33 of the power conversion device 30 according to the second embodiment.
  • the control unit 33 determines whether to stop the motor 11a. When not stopping the motor 11a (S201: No), the control part 33 repeats the determination process of step S201, driving the motor 11a. On the other hand, when stopping the motor 11a (S201: Yes), the process of the control part 33 progresses to step S202. In step S202, the control unit 33 alternately repeats “first control” and “second control”. The “first control” and “second control” will be described later.
  • step S203 the control unit 33 determines whether a predetermined time has elapsed since the start of the control in step S202.
  • the predetermined time has not elapsed since the start of the control in step S202 (S203: No)
  • the process of the control unit 33 returns to step S202.
  • the control unit 33 ends the series of processes (END). Then, although omitted in FIG. 9, the control unit 33 turns off the switching elements S1 to S6.
  • step S202 the “first control” in step S202 will be described with reference to FIG. 10 (a), and the “second control” will be described with reference to FIG. 10 (b).
  • FIG. 10A is an explanatory diagram of “first control” of the power conversion device 30.
  • the control unit 33 switches the switching elements S1 to S6 of the upper arm and the lower arm so as to electrically connect the windings gu, gv, gw of the motor 11a and the smoothing capacitor C (DC power supply).
  • the control unit 33 turns on the switching element S5 of the upper arm and the switching element S4 of the lower arm, and turns off the other switching elements S1 to S3 and S6.
  • the DC voltage of the smoothing capacitor C is applied to the windings gu, gv, gw of the motor 11a, and a force for braking the reverse rotation of the motor 11a is generated.
  • the switching elements S2 and S3 may be turned on, and the other switching elements S1, S4 to S6 may be turned off.
  • FIG. 10B is an explanatory diagram of “second control” of the power conversion device 30.
  • the control unit 33 turns off the switching elements S1, S3, and S5 of the upper arm and the switching elements S2, S4, and S6 of the lower arm.
  • a return current in a direction that prevents reverse rotation of the motor 11a flows through the return diode D and the like due to the inductances of the windings gu, gv, and gw of the motor 11a. Therefore, also in the “second control”, the reverse rotation of the motor 11a is suppressed.
  • the “second control” is the same as the “second state” (see FIG. 4B) described in the first embodiment.
  • the on-duty of the switching elements S4 and S5 may be increased. .
  • transient current fluctuations and torque fluctuations immediately after the motor 11a is stopped can be suppressed.
  • the “first state” and the “second state” may be repeated sequentially.
  • the control unit 33 turns on all the switching elements S2, S4, and S6 of the lower arm in the “first state” has been described.
  • the present invention is not limited to this.
  • the switching elements S2 and S4 of the lower arm may be turned on, and the other switching elements S1, S3, S5, and S6 may be turned off. That is, when the motor 11a is stopped, the control unit 33 turns on at least two of the switching elements of one of the upper arm and the lower arm and turns off the other switching element;
  • the “second state” in which the switching elements S1 to S6 of the upper arm and the lower arm are turned off may be alternately repeated. Even with such control, current fluctuation and torque fluctuation of the motor 11a can be suppressed.
  • the control unit 33 determines that the “first state” and the “second state” described in the first embodiment.
  • the motor 11a may be stopped by repeating the above.
  • the motor 11a when the motor 11a is overloaded or when an overcurrent that can demagnetize the permanent magnet of the motor 11a flows, the motor 11a can be stopped while suppressing reverse rotation.
  • the control described above can also be applied to the second embodiment.
  • each embodiment demonstrated the structure where the motor 11a is a three-phase motor, it is not restricted to this.
  • each embodiment can be applied to a single-phase motor.
  • each embodiment demonstrated the case where the power converter device 30 was applied to control of the motor 11a of the compressor 11, it is not restricted to this. That is, each embodiment can also be applied to other devices (for example, pumps) configured such that when the motor is stopped, the motor rotates in reverse by the pressure difference between the suction side and the discharge side.
  • the present invention is not limited to this. That is, if the compressor 11 has a characteristic that a differential pressure is generated on the suction side and the discharge side when the compressor 11 is stopped and the motor 11a rotates in reverse due to the differential pressure, other types of compressors (for example, a helical type) The present embodiment can also be applied to a compressor.
  • the present invention is not limited to this.
  • a shunt resistor (not shown) is provided on the DC bus, and the control unit 33 controls on / off of the switching elements S1 to S6 based on the detected value of the current flowing through the shunt resistor. Also good.
  • each embodiment demonstrated the structure with which the air conditioner 100 was provided with the four-way valve 15, it is not restricted to this. That is, the four-way valve 15 may be omitted, and an air conditioner dedicated to cooling or heating may be used.
  • SYMBOLS 100 Air conditioner 10 Refrigerant circuit 11 Compressor 11a Motor 12 Outdoor heat exchanger (condenser, evaporator) 13 Expansion valve 14 Indoor heat exchanger (evaporator, condenser) DESCRIPTION OF SYMBOLS 15 Four way valve 30 Power converter 31 Power converter 31a Bridge circuit 31b Gate driver 32 Current detection part 33 Control part 33a Inverter control part 33b Pulse control part 20 Converter part (DC power supply) C Smoothing capacitor (DC power supply) F2 Indoor fan S1, S3, S5 Switching element (Upper arm switching element) S2, S4, S6 Switching element (lower arm switching element) gu, gv, gw winding

Abstract

Provided is a highly reliable power conversion device. This power conversion device (30) is equipped with: a power conversion unit (31), which has upper arm switching elements (S1, S3, and S5) connected to the positive side of a smoothing capacitor (C) and lower arm switching elements (S2, S4, and S6) connected to the negative side of the smoothing capacitor (C), and which converts DC voltage applied from the smoothing capacitor (C) to a drive voltage for a motor (11a); and a control unit (33) which, when the motor (11a) is stopped, alternately repeats a first state in which at least two of the switching elements of one of the arms, that is, the upper arm or the lower arm, are turned on, and the other switching elements are turned off, and a second state in which the upper arm switching elements and the lower arm switching elements (S1-S6) are turned off.

Description

電力変換装置及びこれを備える空気調和機Power conversion device and air conditioner equipped with the same
　本発明は、電力変換装置等に関する。 The present invention relates to a power conversion device and the like.
　スクロール型の圧縮機の吸込側又は吐出側に逆止弁を設けた空気調和機が知られている。このような逆止弁を設けることで、圧縮機駆動用のモータが停止した後、圧縮機の吐出側・吸込側の差圧によるモータの逆回転を防止し、唸り音や振動を抑制するようにしている。 An air conditioner in which a check valve is provided on the suction side or discharge side of a scroll compressor is known. By providing such a check valve, after the motor for driving the compressor stops, the reverse rotation of the motor due to the differential pressure on the discharge side and the suction side of the compressor is prevented, and the noise and vibration are suppressed. I have to.
　その一方で、圧縮機に逆止弁を設けると、部品点数の増加やコストアップを招き、また、逆止弁における冷媒の圧力損失によって圧縮機の効率が低下するという事情がある。そこで、圧縮機に逆止弁を設けることなく、モータの逆回転を抑制する技術として、例えば、特許文献１，２に記載の技術が知られている。 On the other hand, if a check valve is provided in the compressor, the number of parts increases and the cost increases, and the efficiency of the compressor decreases due to the pressure loss of refrigerant in the check valve. Therefore, for example, techniques described in Patent Documents 1 and 2 are known as techniques for suppressing reverse rotation of the motor without providing a check valve in the compressor.
　すなわち、特許文献１には、インバータ装置の正電圧側又は負電圧側の全てのスイッチング素子を通電することによって、コンプレッサモータの運転停止後の逆回転を防止することが記載されている。 That is, Patent Document 1 describes preventing reverse rotation after stopping the operation of the compressor motor by energizing all switching elements on the positive voltage side or the negative voltage side of the inverter device.
　また、特許文献２には、直流電源の正極に接続される第１のスイッチング素子群、又は直流電源の負極に接続される第２のスイッチング素子群を同時に導通状態にすることによって、直流ブラシレスモータの運転停止後の逆回転を防止することが記載されている。 Patent Document 2 discloses a DC brushless motor by simultaneously bringing a first switching element group connected to a positive electrode of a DC power supply or a second switching element group connected to a negative electrode of a DC power supply into a conductive state. It is described that the reverse rotation after the operation stop is prevented.
特開２０００－２８７４８５号公報JP 2000-287485 A 特開平１１－４６４９４号公報Japanese Patent Laid-Open No. 11-46494
　特許文献１，２に記載の技術では、モータの停止時に正電圧側等のスイッチング素子がオン状態で維持される。そうすると、モータの巻線に流れる電流が誘起電圧によって過渡的に大きく変動し、それに伴ってモータのトルクも大きく変動するため、唸り音や振動が生じる可能性がある。また、モータの巻線に大きな電流が流れるため、場合によっては、モータの永久磁石で減磁が生じたり、前記したスイッチング素子に不具合が生じたりする可能性もある。 In the techniques described in Patent Documents 1 and 2, the switching elements on the positive voltage side and the like are maintained in the ON state when the motor is stopped. As a result, the current flowing through the winding of the motor greatly fluctuates transiently due to the induced voltage, and the torque of the motor also fluctuates greatly accordingly, which may cause a roaring sound or vibration. In addition, since a large current flows through the winding of the motor, depending on the case, demagnetization may occur in the permanent magnet of the motor or a malfunction may occur in the switching element described above.
　そこで、本発明は、信頼性の高い電力変換装置等を提供することを課題とする。 Therefore, an object of the present invention is to provide a highly reliable power conversion device and the like.
　前記課題を解決するために、本発明は、モータの停止時に、上アーム及び下アームのうち一方のスイッチング素子の少なくとも２つをオン状態とし、他方のスイッチング素子をオフ状態とする第１の状態と、上アーム及び下アームのスイッチング素子をオフ状態とする第２の状態と、を交互に繰り返すことを特徴とする。 In order to solve the above-described problem, the present invention provides a first state in which at least two switching elements of one of the upper arm and the lower arm are turned on and the other switching element is turned off when the motor is stopped. And a second state in which the switching elements of the upper arm and the lower arm are turned off alternately.
　また、本発明は、モータの停止時に、モータの巻線と直流電源とを電気的に接続するように上アーム及び下アームのスイッチング素子を制御する第１制御と、上アーム及び下アームのスイッチング素子をオフ状態にする第２制御と、を交互に繰り返すことを特徴とする。 The present invention also provides a first control for controlling the switching elements of the upper arm and the lower arm so as to electrically connect the motor winding and the DC power source when the motor is stopped, and the switching of the upper arm and the lower arm. The second control for turning off the element is alternately repeated.
　本発明によれば、信頼性の高い電力変換装置等を提供できる。 According to the present invention, a highly reliable power conversion device or the like can be provided.
本発明の第１実施形態に係る電力変換装置を備える空気調和機の構成図である。It is a block diagram of an air conditioner provided with the power converter device which concerns on 1st Embodiment of this invention. 本発明の第１実施形態に係る電力変換装置を含む構成図である。It is a block diagram containing the power converter device which concerns on 1st Embodiment of this invention. 本発明の第１実施形態に係る電力変換装置の制御部が実行する処理のフローチャートである。It is a flowchart of the process which the control part of the power converter device which concerns on 1st Embodiment of this invention performs. 本発明の第１実施形態に係る電力変換装置に関する説明図であり、（ａ）は電力変換装置の「第１の状態」を示す説明図であり、（ｂ）は電力変換装置の「第２の状態」を示す説明図である。It is explanatory drawing regarding the power converter device which concerns on 1st Embodiment of this invention, (a) is explanatory drawing which shows "the 1st state" of a power converter device, (b) is "2nd of a power converter device. FIG. （ａ）は下アームのスイッチング素子におけるオンデューティの指令信号の説明図であり、（ｂ）は下アームのスイッチング素子のオン・オフを示すパルス信号の説明図である。(A) is explanatory drawing of the on-duty command signal in the switching element of a lower arm, (b) is explanatory drawing of the pulse signal which shows ON / OFF of the switching element of a lower arm. （ａ）は下アームのスイッチング素子におけるオンデューティの指令信号に関する別の例の説明図であり、（ｂ）は下アームのスイッチング素子のオン・オフを示すパルス信号の説明図である。(A) is explanatory drawing of the other example regarding the command signal of on-duty in the switching element of a lower arm, (b) is explanatory drawing of the pulse signal which shows ON / OFF of the switching element of a lower arm. 本発明の第１実施形態に係る電力変換装置を備える空気調和機において、圧縮機の回転速度、モータのトルク、及びモータに流れる電流の変化を示す実験結果である。It is an experimental result which shows the rotation speed of a compressor, the torque of a motor, and the change of the electric current which flows into a motor in an air conditioner provided with the power converter device which concerns on 1st Embodiment of this invention. 本発明の第１実施形態及び比較例における圧縮機の運転効率を示す説明図である。It is explanatory drawing which shows the operating efficiency of the compressor in 1st Embodiment of this invention and a comparative example. 本発明の第２実施形態に係る電力変換装置の制御部が実行する処理のフローチャートである。It is a flowchart of the process which the control part of the power converter device which concerns on 2nd Embodiment of this invention performs. 本発明の第２実施形態に係る電力変換装置に関する説明図であり、（ａ）は電力変換装置の「第１制御」の説明図であり、（ｂ）は電力変換装置の「第２制御」の説明図である。It is explanatory drawing regarding the power converter device which concerns on 2nd Embodiment of this invention, (a) is explanatory drawing of "1st control" of a power converter device, (b) is "2nd control" of a power converter device. It is explanatory drawing of. 比較例に係る空気調和機において、圧縮機の回転速度、モータのトルク、及びモータに流れる電流の変化を示す実験結果である。In the air conditioner which concerns on a comparative example, it is an experimental result which shows the change of the rotational speed of a compressor, the torque of a motor, and the electric current which flows into a motor.
≪第１実施形態≫
＜空気調和機の構成＞
　図１は、第１実施形態に係る電力変換装置３０を備える空気調和機１００の構成図である。
　空気調和機１００は、ヒートポンプサイクルで冷媒を循環させることによって空調（冷房運転、暖房運転、除湿運転等）を行う機器である。図１に示すように、空気調和機１００は、冷媒回路１０と、室外ファンＦ１と、室内ファンＦ２と、を備えている。また、空気調和機１００は、前記した構成の他に、コンバータ部２０と、電力変換装置３０と、を備えるとともに、図１では図示を省略したが、電気系に平滑キャパシタＣ（図２参照）を備えている。 << First Embodiment >>
<Configuration of air conditioner>
FIG. 1 is a configuration diagram of an air conditioner 100 including a power conversion device 30 according to the first embodiment.
The air conditioner 100 is a device that performs air conditioning (cooling operation, heating operation, dehumidifying operation, etc.) by circulating a refrigerant in a heat pump cycle. As shown in FIG. 1, the air conditioner 100 includes a refrigerant circuit 10, an outdoor fan F1, and an indoor fan F2. In addition to the above-described configuration, the air conditioner 100 includes a converter unit 20 and a power conversion device 30. Although not shown in FIG. 1, a smoothing capacitor C (see FIG. 2) is included in the electrical system. It has.
　冷媒回路１０は、圧縮機１１と、室外熱交換器１２と、膨張弁１３と、室内熱交換器１４と、が四方弁１５を介して環状に順次接続された回路である。 The refrigerant circuit 10 is a circuit in which a compressor 11, an outdoor heat exchanger 12, an expansion valve 13, and an indoor heat exchanger 14 are sequentially connected in an annular manner via a four-way valve 15.
　圧縮機１１は、ガス状の冷媒を圧縮する機器であり、駆動源のモータ１１ａを備えている。圧縮機１１は、例えば、スクロール型の圧縮機であり、その停止時において吸込側・吐出側に差圧が生じるという特性を有している。前記した差圧によって、仮にモータ１１ａが高速で逆回転すると、誘起電圧によって過渡的な電流変動やトルク変動が生じる。その一方で、モータ１１ａの逆回転を規制する逆止弁（図示せず）を設けると、部品点数の増加やコストアップを招く。したがって、本実施形態では一例として、圧縮機１１に逆止弁を設けない構成とし、電力変換装置３０の制御によってモータ１１ａの逆回転を抑制するようにしている。 The compressor 11 is a device that compresses a gaseous refrigerant and includes a motor 11a as a drive source. The compressor 11 is, for example, a scroll-type compressor, and has a characteristic that a differential pressure is generated on the suction side and the discharge side when the compressor 11 is stopped. If the motor 11a reversely rotates at a high speed due to the above-described differential pressure, transient current fluctuations and torque fluctuations occur due to the induced voltage. On the other hand, if a check valve (not shown) for restricting the reverse rotation of the motor 11a is provided, the number of parts increases and the cost increases. Therefore, in this embodiment, as an example, the compressor 11 is not provided with a check valve, and the reverse rotation of the motor 11 a is suppressed by the control of the power converter 30.
　四方弁１５は、冷媒の流れる向きを切り替える弁である。すなわち、冷房運転時（図１の破線矢印）には、室外熱交換器１２を凝縮器として機能させ、室内熱交換器１４を蒸発器として機能させるように四方弁１５が制御される。一方、暖房運転時（図１の実線矢印）には、室内熱交換器１４を凝縮器として機能させ、室外熱交換器１２を蒸発器として機能させるように四方弁１５が制御される。つまり、冷媒回路１０は、圧縮機１１と、凝縮器（室外熱交換器１２・室内熱交換器１４の一方）と、膨張弁１３と、蒸発器（室外熱交換器１２・室内熱交換器１４の他方）と、が四方弁１５を介して環状に順次接続された構成になっている。 The four-way valve 15 is a valve that switches the flow direction of the refrigerant. That is, during the cooling operation (broken line arrow in FIG. 1), the four-way valve 15 is controlled so that the outdoor heat exchanger 12 functions as a condenser and the indoor heat exchanger 14 functions as an evaporator. On the other hand, during the heating operation (solid arrow in FIG. 1), the four-way valve 15 is controlled so that the indoor heat exchanger 14 functions as a condenser and the outdoor heat exchanger 12 functions as an evaporator. That is, the refrigerant circuit 10 includes a compressor 11, a condenser (one of the outdoor heat exchanger 12 and the indoor heat exchanger 14), an expansion valve 13, and an evaporator (the outdoor heat exchanger 12 and the indoor heat exchanger 14). And the other) are sequentially connected in an annular manner via a four-way valve 15.
　室外熱交換器１２は、外気と冷媒との間で熱交換が行われる熱交換器である。
　室外ファンＦ１は、室外熱交換器１２に外気を送り込むファンであり、室外熱交換器１２の付近に設置されている。 The outdoor heat exchanger 12 is a heat exchanger that exchanges heat between outside air and refrigerant.
The outdoor fan F <b> 1 is a fan that sends outside air to the outdoor heat exchanger 12, and is installed in the vicinity of the outdoor heat exchanger 12.
　室内熱交換器１４は、室内空気（空調対象空間の空気）と冷媒との間で熱交換が行われる熱交換器である。
　室内ファンＦ２は、室内熱交換器１４に室内空気を送り込むファンであり、室内熱交換器１４の付近に設置されている。 The indoor heat exchanger 14 is a heat exchanger in which heat is exchanged between room air (air in the air-conditioning target space) and the refrigerant.
The indoor fan F <b> 2 is a fan that sends room air into the indoor heat exchanger 14, and is installed near the indoor heat exchanger 14.
　膨張弁１３は、前記した「凝縮器」で凝縮した冷媒を減圧する弁である。膨張弁１３によって減圧された冷媒は、前記した「蒸発器」に導かれる。そして、各種センサ（図示せず）の検出値やリモコン（図示せず）からの操作信号等に基づいて、空気調和機１００の各機器が制御されるようになっている。 The expansion valve 13 is a valve that depressurizes the refrigerant condensed in the “condenser”. The refrigerant decompressed by the expansion valve 13 is guided to the “evaporator” described above. And each apparatus of the air conditioner 100 is controlled based on the detection value of various sensors (not shown), the operation signal from a remote control (not shown), etc.
　コンバータ部２０は、交流電源Ｅから印加される交流電圧を直流電圧に変換する電力変換器である。なお、コンバータ部２０は、前記した直流電圧の高さを調整する機能も有している。
　電力変換装置３０は、所定の直流電圧をモータ１１ａの駆動電圧（つまり、三相交流電圧）に変換する装置である。 The converter unit 20 is a power converter that converts an AC voltage applied from the AC power source E into a DC voltage. The converter unit 20 also has a function of adjusting the height of the DC voltage described above.
The power converter 30 is a device that converts a predetermined DC voltage into a driving voltage (that is, a three-phase AC voltage) of the motor 11a.
＜電力変換装置の構成＞
　図２は、電力変換装置３０を含む構成図である。
　図２に示す平滑キャパシタＣは、コンバータ部２０から印加される電圧（脈流を含む直流電圧）を平滑化するキャパシタであり、その正側・負側がコンバータ部２０に接続されている。 <Configuration of power converter>
FIG. 2 is a configuration diagram including the power conversion device 30.
The smoothing capacitor C shown in FIG. 2 is a capacitor that smoothes the voltage (DC voltage including pulsating current) applied from the converter unit 20, and the positive side and the negative side are connected to the converter unit 20.
　図２に示すように、電力変換装置３０は、電力変換部３１と、電流検出部３２と、制御部３３と、を備えている。
　電力変換部３１は、「直流電源」から印加される直流電圧をモータ１１ａの駆動電圧に変換するインバータ回路である。なお、前記した「直流電源」は、交流電源Ｅと、コンバータ部２０と、平滑キャパシタＣと、を含んで構成される。 As shown in FIG. 2, the power conversion device 30 includes a power conversion unit 31, a current detection unit 32, and a control unit 33.
The power conversion unit 31 is an inverter circuit that converts a DC voltage applied from a “DC power supply” into a drive voltage of the motor 11a. The “DC power supply” described above includes an AC power supply E, a converter unit 20 and a smoothing capacitor C.
　図２に示すように、電力変換部３１は、ブリッジ回路３１ａと、ゲート・ドライバ３１ｂと、を備えている。
　ブリッジ回路３１ａは、平滑キャパシタＣ（直流電源）の正側に接続される上アームのスイッチング素子Ｓ１，Ｓ３，Ｓ５と、平滑キャパシタＣ（直流電源）の負側に接続される下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６と、を備えている。スイッチング素子Ｓ１～Ｓ６には、それぞれ、還流ダイオードＤが逆並列に接続されている。 As shown in FIG. 2, the power conversion unit 31 includes a bridge circuit 31a and a gate driver 31b.
The bridge circuit 31a includes upper arm switching elements S1, S3, S5 connected to the positive side of the smoothing capacitor C (DC power supply) and a lower arm switching element connected to the negative side of the smoothing capacitor C (DC power supply). S2, S4, and S6. A free-wheeling diode D is connected to the switching elements S1 to S6 in antiparallel.
　スイッチング素子Ｓ１～Ｓ６は、例えば、ＭＯＳＦＥＴ（Metal-Oxide-Semiconductor Field-Effect Transistor）であり、制御部３３からの指令によって、そのオン・オフが切り替わるようになっている。なお、スイッチング素子Ｓ１～Ｓ６として、ＩＧＢＴ（Insulated Gate Bipolar Transistor）等、他の種類の素子を用いてもよい。 The switching elements S1 to S6 are, for example, MOSFETs (Metal-Oxide-Semiconductor-Field-Effect-Transistors), and are switched on / off by a command from the control unit 33. As switching elements S1 to S6, other types of elements such as IGBT (Insulated Gate Bipolar Transistor) may be used.
　図２に示すように、平滑キャパシタＣの正側にドレインが接続されるスイッチング素子Ｓ１と、平滑キャパシタＣの負側にソースが接続されるスイッチング素子Ｓ２と、の接続点が、Ｗ相の配線に接続されている（Ｕ相、Ｖ相についても同様）。
　なお、スイッチング素子Ｓ１～Ｓ６の電流容量を、所定の減磁電流値（モータ１１ａの永久磁石において減磁が生じ始める電流値）以上にすることが好ましい。これによって、減磁電流値に近い大きな電流がスイッチング素子Ｓ１～Ｓ６に流れたとしても、これらのスイッチング素子Ｓ１～Ｓ６の不具合を防止できるからである。 As shown in FIG. 2, the connection point between the switching element S1 whose drain is connected to the positive side of the smoothing capacitor C and the switching element S2 whose source is connected to the negative side of the smoothing capacitor C is a W-phase wiring. (The same applies to the U-phase and V-phase).
Note that the current capacities of the switching elements S1 to S6 are preferably equal to or greater than a predetermined demagnetization current value (current value at which demagnetization starts in the permanent magnet of the motor 11a). This is because even if a large current close to the demagnetizing current value flows through the switching elements S1 to S6, it is possible to prevent the problems of the switching elements S1 to S6.
　ゲート・ドライバ３１ｂは、パルス制御部３３ｂから入力されるパルス信号に基づいて、スイッチング素子Ｓ１～Ｓ６のゲートに所定の電圧を印加する（つまり、ゲート信号を出力する）機能を有している。 The gate driver 31b has a function of applying a predetermined voltage (that is, outputting a gate signal) to the gates of the switching elements S1 to S6 based on the pulse signal input from the pulse control unit 33b.
　電流検出部３２は、モータ１１ａの巻線ｇｕ，ｇｖ，ｇｗに流れる電流を検出するものであり、図２に示す例では、Ｕ相・Ｖ相・Ｗ相の配線にそれぞれ設置されている。電流検出部３２の検出値は、後記するインバータ制御部３３ａに出力される。 The current detector 32 detects the current flowing through the windings gu, gv, and gw of the motor 11a, and is installed in the U-phase, V-phase, and W-phase wirings in the example shown in FIG. The detection value of the current detection unit 32 is output to an inverter control unit 33a described later.
　制御部３３は、モータ１１ａの巻線ｇｕ，ｇｖ，ｇｗに流れる電流の検出値に基づいて、スイッチング素子Ｓ１～Ｓ６のオン・オフを制御する機能を有している。制御部３３は、図示はしないが、ＣＰＵ（Central Processing Unit）、ＲＯＭ（Read Only Memory）、ＲＡＭ（Random Access Memory）、各種インタフェース等の電子回路を含んで構成されている。そして、ＲＯＭに記憶されたプログラムを読み出してＲＡＭに展開し、ＣＰＵが各種処理を実行するようになっている。 The control unit 33 has a function of controlling on / off of the switching elements S1 to S6 based on detection values of currents flowing through the windings gu, gv, and gw of the motor 11a. Although not illustrated, the control unit 33 includes electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces. Then, the program stored in the ROM is read out and expanded in the RAM, and the CPU executes various processes.
　図２に示すように、制御部３３は、インバータ制御部３３ａと、パルス制御部３３ｂと、を備えている。
　インバータ制御部３３ａは、モータ１１ａの巻線ｇｕ，ｇｖ，ｇｗに流れる電流の検出値に基づいて、パルス制御部３３ｂに所定の印加電圧指令（巻線ｇｕ，ｇｖ，ｇｗに印加する三相交流電圧の指令値）を出力する機能を有している。 As shown in FIG. 2, the control unit 33 includes an inverter control unit 33a and a pulse control unit 33b.
The inverter control unit 33a is configured to apply a predetermined applied voltage command (three-phase AC applied to the windings gu, gv, gw) to the pulse control unit 33b based on the detected value of the current flowing in the windings gu, gv, gw of the motor 11a. (Command value of voltage) is output.
　パルス制御部３３ｂは、インバータ制御部３３ａから入力される印加電圧指令に基づき、ＰＷＭ制御（Pulse Width Modulation）によって、所定のパルス信号を生成する機能を有している。パルス制御部３３ｂによって生成されたパルス信号は、前記したように、ゲート・ドライバ３１ｂに出力される。
　その他、図２では省略したが、制御部３３は、コンバータ部２０の昇圧動作を制御する機能も有している。 The pulse control unit 33b has a function of generating a predetermined pulse signal by PWM control (Pulse Width Modulation) based on the applied voltage command input from the inverter control unit 33a. The pulse signal generated by the pulse controller 33b is output to the gate driver 31b as described above.
In addition, although omitted in FIG. 2, the control unit 33 also has a function of controlling the boosting operation of the converter unit 20.
＜制御部の処理＞
　図３は、電力変換装置３０の制御部３３が実行する処理のフローチャートである。
　なお、図３の「ＳＴＡＲＴ」時には、モータ１１ａが正回転で駆動しているものとする。つまり、図３の「ＳＴＡＲＴ」時には、圧縮機１１の駆動によって所定の空調運転が行われているものとする。
　ステップＳ１０１において制御部３３は、モータ１１ａを停止させるか否かを判定する。つまり、制御部３３は、空調運転の停止又はサーモオフの指令が自身に入力されたか否かを判定する。 <Processing of control unit>
FIG. 3 is a flowchart of processing executed by the control unit 33 of the power conversion device 30.
In addition, at the time of “START” in FIG. 3, it is assumed that the motor 11a is driven in the forward rotation. That is, at the time of “START” in FIG. 3, it is assumed that a predetermined air conditioning operation is performed by driving the compressor 11.
In step S101, the control unit 33 determines whether to stop the motor 11a. That is, the control unit 33 determines whether or not a command for stopping the air-conditioning operation or thermo-off is input to itself.
　ステップＳ１０１においてモータ１１ａを停止させない場合（Ｓ１０１：Ｎｏ）、制御部３３は、モータ１１ａを駆動させつつ、ステップＳ１０１の判定処理を繰り返す。一方、ステップＳ１０１においてモータ１１ａを停止させる場合（Ｓ１０１：Ｙｅｓ）、制御部３３の処理はステップＳ１０２に進む。 When the motor 11a is not stopped in step S101 (S101: No), the control unit 33 repeats the determination process of step S101 while driving the motor 11a. On the other hand, when stopping the motor 11a in step S101 (S101: Yes), the process of the control part 33 progresses to step S102.
　ステップＳ１０２において制御部３３は、コンバータ部２０の昇圧動作を停止させる。詳細については後記するが、次のステップＳ１０３の処理では、モータ１１ａの巻線ｇｕ，ｇｖ，ｇｗと平滑キャパシタＣとが電気的に遮断され、コンバータ部２０からモータ１１ａにエネルギが出力されない状態になる。ステップＳ１０３の処理中、仮にコンバータ部２０の昇圧動作が継続されていると、平滑キャパシタＣの電圧が上昇し、その耐圧を超える可能性がある。したがって、本実施形態では、ステップＳ１０３の制御を行う前に、制御部３３がコンバータ部２０の昇圧動作を停止させるようにしている。これによって、平滑キャパシタＣを保護できるとともに、ゲート・ドライバ３１ｂに印加される電圧を所定の許容範囲内に抑えることができる。 In step S102, the control unit 33 stops the boosting operation of the converter unit 20. Although details will be described later, in the process of the next step S103, the windings gu, gv, gw of the motor 11a and the smoothing capacitor C are electrically disconnected, and no energy is output from the converter unit 20 to the motor 11a. Become. If the step-up operation of the converter unit 20 is continued during the process of step S103, the voltage of the smoothing capacitor C may increase and exceed the breakdown voltage. Therefore, in the present embodiment, the control unit 33 stops the boosting operation of the converter unit 20 before performing the control of step S103. As a result, the smoothing capacitor C can be protected, and the voltage applied to the gate driver 31b can be suppressed within a predetermined allowable range.
　次に、ステップＳ１０３において制御部３３は、「第１の状態」と「第２の状態」とを交互に繰り返す。ここで、次のステップＳ１０４，Ｓ１０５を説明する前に、ステップＳ１０３の「第１の状態」について図４（ａ）を参照して説明し、さらに、「第２の状態」について図４（ｂ）を参照して説明する。 Next, in step S103, the control unit 33 alternately repeats the “first state” and the “second state”. Here, before describing the next steps S104 and S105, the “first state” of step S103 will be described with reference to FIG. 4A, and further, the “second state” will be described with reference to FIG. ) Will be described.
　図４（ａ）は、電力変換装置３０の「第１の状態」を示す説明図である。
　「第１の状態」において制御部３３は、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６をオン状態とし、上アームのスイッチング素子Ｓ１，Ｓ３，Ｓ５をオフ状態とする。圧縮機１１の吸込側・吐出側の差圧によってモータ１１ａが逆回転すると、この逆回転を妨げる誘起電圧（逆起電力）が巻線ｇｕ，ｇｖ，ｇｗに生じる。その結果、スイッチング素子Ｓ２，Ｓ４，Ｓ６及び巻線ｇｕ，ｇｖ，ｇｗを介して、モータ１１ａの逆回転を妨げるように電流が流れる。これによって、圧縮機１１の吸込側・吐出側の差圧によるモータ１１ａの逆回転が抑制される。 FIG. 4A is an explanatory diagram showing a “first state” of the power conversion device 30.
In the “first state”, the control unit 33 turns on the switching elements S2, S4, S6 of the lower arm and turns off the switching elements S1, S3, S5 of the upper arm. When the motor 11a rotates reversely due to the differential pressure between the suction side and the discharge side of the compressor 11, an induced voltage (back electromotive force) that prevents the reverse rotation is generated in the windings gu, gv, and gw. As a result, a current flows through the switching elements S2, S4, S6 and the windings gu, gv, gw so as to prevent reverse rotation of the motor 11a. Thereby, the reverse rotation of the motor 11a due to the differential pressure between the suction side and the discharge side of the compressor 11 is suppressed.
　図４（ｂ）は、電力変換装置３０の「第２の状態」を示す説明図である。
　「第２の状態」において制御部３３は、上アームのスイッチング素子Ｓ１，Ｓ３，Ｓ５、及び下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６をオフ状態とする。そうすると、モータ１１ａの巻線ｇｕ，ｇｖ，ｇｗのインダクタンスによって、モータ１１ａの逆回転を妨げる向きの還流電流が、還流ダイオードＤ等を介して流れる。したがって、この「第２の状態」においても、モータ１１ａの逆回転が抑制される。 FIG. 4B is an explanatory diagram showing a “second state” of the power conversion device 30.
In the “second state”, the control unit 33 turns off the switching elements S1, S3, and S5 of the upper arm and the switching elements S2, S4, and S6 of the lower arm. If it does so, the recirculation | reflux current of the direction which prevents reverse rotation of the motor 11a will flow through the recirculation | diode diode D etc. by the inductance of coil | winding gu, gv, and gw of the motor 11a. Therefore, the reverse rotation of the motor 11a is also suppressed in this “second state”.
　また、スイッチング素子Ｓ１～Ｓ６の全てをオフ状態とする「第２の状態」は、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６をオン状態にして短絡する「第１の状態」に比べて、巻線ｇｕ，ｇｖ，ｇｗに流れる電流の振幅が小さくなる。したがって、モータ１１ａの逆回転を抑制しつつ、モータ１１ａにおける電流変動やトルク変動を抑制できる。 In addition, the “second state” in which all of the switching elements S1 to S6 are turned off is compared to the “first state” in which the switching elements S2, S4, S6 of the lower arm are turned on and short-circuited. The amplitude of the current flowing through the lines gu, gv, gw is reduced. Therefore, current fluctuation and torque fluctuation in the motor 11a can be suppressed while suppressing reverse rotation of the motor 11a.
　図４（ａ）に示す「第１の状態」と、図４（ｂ）に示す「第２の状態」と、を交互に繰り返すことによって（Ｓ１０３：図３参照）、巻線ｇｕ，ｇｖ，ｇｗに生じる誘起電圧の急激な変動が抑制され、過渡的な電流変動やトルク変動を抑制できる。次に、ステップＳ１０３における下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオンデューティの変化について説明する。 By alternately repeating the “first state” shown in FIG. 4A and the “second state” shown in FIG. 4B (S103: see FIG. 3), the windings gu, gv, Sudden fluctuations in the induced voltage generated in gw are suppressed, and transient current fluctuations and torque fluctuations can be suppressed. Next, the change in the on-duty of the switching elements S2, S4, S6 of the lower arm in step S103 will be described.
　図５（ａ）は、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６におけるオンデューティの指令信号の説明図である。
　なお、図５（ａ）の横軸は、モータ１１ａの駆動停止時から経過した時間である。図５（ａ）の縦軸は、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオンデューティを示す指令信号である。
　図５（ａ）の値“１”に漸近する単調増加の指令信号（実線）は、例えば、ステップ関数を周知の一次遅れフィルタ（図示せず）に入力することによって生成される。この指令信号は、インバータ制御部３３ａ（図２参照）において生成され、パルス制御部３３ｂ（図２参照）に出力される。 FIG. 5A is an explanatory diagram of an on-duty command signal in the switching elements S2, S4, and S6 of the lower arm.
In addition, the horizontal axis of Fig.5 (a) is the time which passed since the drive stop of the motor 11a. The vertical axis in FIG. 5A is a command signal indicating the on-duty of the switching elements S2, S4, S6 of the lower arm.
The monotonously increasing command signal (solid line) that gradually approaches the value “1” in FIG. 5A is generated by, for example, inputting a step function to a well-known first-order lag filter (not shown). This command signal is generated in the inverter control unit 33a (see FIG. 2) and output to the pulse control unit 33b (see FIG. 2).
　また、制御部３３は、「第１の状態」と「第２の状態」とを交互に繰り返す過程（Ｓ１０３）で、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオンデューティを増加させる。仮に、モータ１１ａの駆動停止の直後に下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオン状態（短絡状態）を継続すると、モータ１１ａの逆回転に伴う誘起電圧が急激に変動し、過渡的な電流変動やトルク変動が生じる可能性がある。 Further, the control unit 33 increases the on-duty of the switching elements S2, S4, and S6 of the lower arm in the process of alternately repeating the “first state” and the “second state” (S103). If the ON state (short circuit state) of the switching elements S2, S4, S6 of the lower arm is continued immediately after the motor 11a is stopped, the induced voltage due to the reverse rotation of the motor 11a fluctuates rapidly, causing a transient current. Variation and torque variation may occur.
　これに対して本実施形態では、前記したように、制御部３３が、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオンデューティを徐々に増加させる。これによって、特にモータ１１ａの駆動停止の直後における過渡的な電流変動やトルク変動を抑制できる。つまり、モータ１１ａの駆動停止の直後は、制御部３３が、モータ１１ａの逆回転に対して緩やかにブレーキトルクを作用させ、その後にブレーキトルクを徐々に増すようにしている。 In contrast, in the present embodiment, as described above, the control unit 33 gradually increases the on-duty of the switching elements S2, S4, and S6 of the lower arm. As a result, transient current fluctuations and torque fluctuations immediately after the motor 11a is stopped can be suppressed. That is, immediately after the drive of the motor 11a is stopped, the control unit 33 gradually applies the brake torque to the reverse rotation of the motor 11a, and then gradually increases the brake torque.
　図５（ｂ）は、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオン・オフを示すパルス信号の説明図である。
　なお、図５（ｂ）の横軸は時間であり、図５（ａ）に対応している。図５（ｂ）の縦軸は、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオン・オフを示すパルス信号である。
　制御部３３は、図５（ａ）の破線で示す三角波のＰＷＭキャリア信号と、同図の実線で示す指令信号と、の比較に基づき、パルス制御部３３ｂによって、図５（ｂ）に示すパルス信号を生成する。 FIG. 5B is an explanatory diagram of a pulse signal indicating ON / OFF of the switching elements S2, S4, and S6 of the lower arm.
In addition, the horizontal axis of FIG.5 (b) is time and respond | corresponds to Fig.5 (a). The vertical axis in FIG. 5B is a pulse signal indicating ON / OFF of the switching elements S2, S4, S6 of the lower arm.
Based on the comparison between the triangular wave PWM carrier signal indicated by the broken line in FIG. 5A and the command signal indicated by the solid line in FIG. 5A, the control unit 33 performs the pulse shown in FIG. Generate a signal.
　すなわち、図５（ａ）の実線で示す指令信号が、破線で示すＰＷＭキャリア信号よりも大きい区間では、“１”を示すパルス信号が、パルス制御部３３ｂ（図２参照）からゲート・ドライバ３１ｂ（図２参照）に出力される。この区間（第１の状態）では、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６がオン状態にされる。 That is, in the section where the command signal indicated by the solid line in FIG. 5A is larger than the PWM carrier signal indicated by the broken line, the pulse signal indicating “1” is sent from the pulse control unit 33b (see FIG. 2) to the gate driver 31b. (See FIG. 2). In this section (first state), the lower arm switching elements S2, S4, and S6 are turned on.
　一方、図５（ａ）の実線で示す指令信号が、破線で示すＰＷＭキャリア信号よりも小さい区間では、“０”を示すパルス信号が、パルス制御部３３ｂ（図２参照）からゲート・ドライバ３１ｂ（図２参照）に出力される。この区間（第２の状態）では、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６がオフ状態にされる。 On the other hand, in a section where the command signal indicated by the solid line in FIG. 5A is smaller than the PWM carrier signal indicated by the broken line, a pulse signal indicating “0” is sent from the pulse control unit 33b (see FIG. 2) to the gate driver 31b. (See FIG. 2). In this section (second state), the lower arm switching elements S2, S4, and S6 are turned off.
　このように、図３のステップＳ１０３では、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオン・オフが交互に切り替えられる。なお、上アームのスイッチング素子Ｓ１，Ｓ３，Ｓ５については、図５（ａ）、（ｂ）では省略したが、ステップＳ１０３の処理中、常時オフ状態である（図４（ａ）、図４（ｂ）参照）。 Thus, in step S103 of FIG. 3, the on / off of the switching elements S2, S4, S6 of the lower arm is alternately switched. Note that the upper arm switching elements S1, S3, and S5 are omitted in FIGS. 5A and 5B, but are always in the OFF state during the process of step S103 (FIGS. 4A and 4B). b)).
　図６（ａ）は、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６におけるオンデューティの指令信号に関する別の例の説明図であり、図６（ｂ）は、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオン・オフを示すパルス信号の説明図である。
　ステップＳ１０３における下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオンデューティは単調増加であればよく、図６（ａ）に示すように、オンデューティの指令信号を直線的に増加させてもよい。そして、図６（ａ）に示す指令信号に基づいて、図６（ｂ）に示すパルス信号が生成される。 FIG. 6A is an explanatory diagram of another example regarding the on-duty command signal in the switching elements S2, S4, S6 of the lower arm, and FIG. 6B is a switching element S2, S4, S6 of the lower arm. It is explanatory drawing of the pulse signal which shows ON / OFF of.
The on-duty of the lower-arm switching elements S2, S4, S6 in step S103 may be monotonously increased, and the on-duty command signal may be increased linearly as shown in FIG. Then, based on the command signal shown in FIG. 6A, the pulse signal shown in FIG. 6B is generated.
　再び、図３に戻って説明を続ける。
　ステップＳ１０３の制御を行った後、ステップＳ１０４において制御部３３は、ステップＳ１０３の制御の開始時から所定時間ｔｓ（図５、図６参照）が経過したか否かを判定する。なお、所定時間ｔｓ（例えば、数秒～数十秒）は、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６のオフ時間が、ゲート・ドライバ３１ｂが動作可能なオフ時間下限値以下になる前に、次のステップＳ１０５の処理が行われるように設定されている。これによって、ゲート・ドライバ３１ｂの誤動作を防止し、モータ１１ａの逆回転を適切に抑制できる。 Returning again to FIG. 3, the description will be continued.
After performing the control in step S103, in step S104, the control unit 33 determines whether or not a predetermined time ts (see FIGS. 5 and 6) has elapsed since the start of the control in step S103. Note that the predetermined time ts (for example, several seconds to several tens of seconds) is the following before the off time of the switching elements S2, S4, S6 of the lower arm becomes equal to or less than the lower limit of the off time during which the gate driver 31b can operate. The process of step S105 is set to be performed. As a result, malfunction of the gate driver 31b can be prevented, and reverse rotation of the motor 11a can be appropriately suppressed.
　ステップＳ１０３の制御の開始時から所定時間ｔｓが経過していない場合（Ｓ１０４：Ｎｏ）、制御部３３の処理はステップＳ１０３に戻る。一方、ステップＳ１０３の制御の開始時から所定時間ｔｓが経過した場合（Ｓ１０４：Ｙｅｓ）、制御部３３の処理はステップＳ１０５に進む。 If the predetermined time ts has not elapsed since the start of the control in step S103 (S104: No), the process of the control unit 33 returns to step S103. On the other hand, when the predetermined time ts has elapsed since the start of the control in step S103 (S104: Yes), the process of the control unit 33 proceeds to step S105.
　ステップＳ１０５において制御部３３は、「第１の状態」を継続する。つまり、制御部３３は、「第１の状態」と「第２の状態」とを交互に繰り返す制御を所定時間ｔｓだけ行った後（Ｓ１０３、Ｓ１０４：Ｙｅｓ）、第１の状態を継続させる（Ｓ１０５）。これによって、前記したように、ゲート・ドライバ３１ｂの誤動作を防止し、また、モータ１１ａの逆回転を停止させるまでの時間を短縮できる。 In step S105, the control unit 33 continues the “first state”. In other words, the control unit 33 continues the first state after performing the control for alternately repeating the “first state” and the “second state” for a predetermined time ts (S103, S104: Yes) ( S105). As a result, as described above, the gate driver 31b can be prevented from malfunctioning, and the time required to stop the reverse rotation of the motor 11a can be shortened.
　ステップＳ１０５の処理を行った後、制御部３３は、一連の処理を終了する（ＥＮＤ）。なお、図３では省略したが、制御部３３は、ステップＳ１０５において「第１の状態」を継続する動作を所定時間行った後、スイッチング素子Ｓ１～Ｓ６をオフ状態にする。 After performing the process of step S105, the control unit 33 ends the series of processes (END). Although omitted in FIG. 3, the control unit 33 performs the operation of continuing the “first state” for a predetermined time in step S105, and then turns off the switching elements S1 to S6.
＜効果＞
　第１実施形態によれば、モータ１１ａの停止時において制御部３３は、「第１の状態」（図４（ａ）参照）と、「第２の状態」（図４（ｂ）参照）と、を交互に繰り返す。これによって、モータ１１ａにおける過渡的な電流変動やトルク変動を抑制できる。 <Effect>
According to the first embodiment, when the motor 11a is stopped, the control unit 33 sets the “first state” (see FIG. 4A) and the “second state” (see FIG. 4B). , Are repeated alternately. Thereby, transient current fluctuations and torque fluctuations in the motor 11a can be suppressed.
　図１１は、比較例における圧縮機１１の回転速度（図１１（ａ）参照）、モータ１１ａ等のトルク（図１１（ｂ）参照）、及びモータ１１ａに流れる電流（図１１（ｃ）参照）の変化を示す実験結果である。なお、図１１（ａ）、（ｂ）、（ｃ）の横軸（時間）は、モータ１１ａの駆動停止時から経過した時間である。 FIG. 11 shows the rotational speed of the compressor 11 in the comparative example (see FIG. 11A), the torque of the motor 11a and the like (see FIG. 11B), and the current flowing in the motor 11a (see FIG. 11C). It is an experimental result which shows the change of. In addition, the horizontal axis (time) of FIG. 11 (a), (b), (c) is the time which passed since the drive stop of the motor 11a.
　比較例では、モータ１１ａの停止後、上アームのスイッチング素子Ｓ１，Ｓ３，Ｓ５をオフ状態で維持し、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６をオン状態で維持するようにしている。つまり、比較例では、スイッチング素子Ｓ１～Ｓ６を「第２の状態」（図４（ｂ）参照）に切り替えることなく、「第１の状態」（図４（ａ）参照）を継続するようにしている。 In the comparative example, after the motor 11a is stopped, the upper arm switching elements S1, S3, and S5 are maintained in the off state, and the lower arm switching elements S2, S4, and S6 are maintained in the on state. That is, in the comparative example, the “first state” (see FIG. 4A) is continued without switching the switching elements S1 to S6 to the “second state” (see FIG. 4B). ing.
　図１１（ａ）に示すように、比較例では、モータ１１ａの停止後、圧縮機１１の吸込側・吐出側の差圧によって、モータ１１ａが値ω１の回転速度で逆回転し始め、その後、回転速度がゼロへと単調減少している。その一方で、図１１（ｃ）に示すように、モータ１１ａの停止直後において、巻線ｇｕ，ｇｖ，ｇｗに流れる電流が大きく変動し、その振幅が所定値Ｉ１を超えている。この所定値Ｉ１は、例えば、モータ１１ａの永久磁石（図示せず）で減磁が生じ始める電流値である。 As shown in FIG. 11A, in the comparative example, after the motor 11a is stopped, the motor 11a starts to reversely rotate at the rotational speed of the value ω1 due to the differential pressure on the suction side and the discharge side of the compressor 11, and then The rotation speed is monotonically decreasing to zero. On the other hand, as shown in FIG. 11 (c), immediately after the motor 11a is stopped, the current flowing through the windings gu, gv, and gw greatly fluctuates, and the amplitude exceeds a predetermined value I1. The predetermined value I1 is, for example, a current value at which demagnetization starts to occur in a permanent magnet (not shown) of the motor 11a.
　図１１（ｃ）に示すように、電流が大きく変動するのは、モータ１１ａが高速で逆回転することによって誘起電圧が急激に変動し、それに伴う電流が、オン状態で維持されているスイッチング素子Ｓ２，Ｓ４，Ｓ６を介して流れるからである。このようにモータ１１ａやスイッチング素子Ｓ２，Ｓ４，Ｓ６に大きな電流が流れると、モータ１１ａが備える永久磁石（図示せず）の減磁や、スイッチング素子Ｓ２，Ｓ４，Ｓ６の不具合を招く可能性がある。 As shown in FIG. 11 (c), the current greatly fluctuates because the induced voltage abruptly fluctuates due to the reverse rotation of the motor 11a and the accompanying current is maintained in the ON state. This is because it flows through S2, S4 and S6. When a large current flows through the motor 11a and the switching elements S2, S4, and S6 as described above, there is a possibility that demagnetization of a permanent magnet (not shown) provided in the motor 11a and problems of the switching elements S2, S4, and S6 are caused. is there.
　また、前記した電流の変動に起因して、図１１（ｂ）に示すように、モータ１１ａの停止直後にトルク（実線）が大きく変動している。このようにモータ１１ａのトルクが大きく変動すると、唸り音や振動が発生して、ユーザに不快感を与える可能性がある。 Also, as shown in FIG. 11 (b), the torque (solid line) greatly fluctuates immediately after the motor 11a is stopped due to the above-described current fluctuation. Thus, if the torque of the motor 11a fluctuates greatly, a roaring sound or vibration may be generated, which may cause discomfort to the user.
　なお、図１１（ｂ）に示す負荷トルク（圧縮機１１の吸込側・吐出側の差圧に起因する逆回転のトルク）は、モータ１１ａの正回転とは逆向き（負の値）であるが、図１１（ｂ）では、その絶対値を示している。そして、モータ１１ａのトルクが負荷トルクに略等しくなると、モータ１１ａの逆回転が止まる（図１１（ａ）参照）。 Note that the load torque shown in FIG. 11B (the reverse rotation torque caused by the differential pressure between the suction side and the discharge side of the compressor 11) is opposite (negative value) to the forward rotation of the motor 11a. However, in FIG. 11B, the absolute value is shown. When the torque of the motor 11a becomes substantially equal to the load torque, the reverse rotation of the motor 11a stops (see FIG. 11A).
　図７は、第１実施形態における圧縮機１１の回転速度（図７（ａ）参照）、モータ１１ａ等のトルク（図７（ｂ）参照）、及びモータ１１ａに流れる電流（図７（ｃ）参照）の変化を示す実験結果である。
　前記したように、「第１の状態」と「第２の状態」とが交互に繰り返されることで（Ｓ１０３：図３参照）、モータ１１ａに流れる電流の振幅が所定値Ｉ１未満に抑えられている（図７（ｃ）参照）。これは、スイッチング素子Ｓ１～Ｓ６をオフ状態とする「第２の状態」において、巻線ｇｕ，ｇｖ，ｇｗに生じる誘起電圧の変動が抑制されたためである。したがって、本実施形態によれば、モータ１１ａが備える永久磁石（図示せず）の減磁や、スイッチング素子Ｓ１～Ｓ６の不具合の発生を防止しつつ、モータ１１ａの停止後の逆回転を抑制できる。 FIG. 7 shows the rotational speed of the compressor 11 (see FIG. 7A), the torque of the motor 11a and the like (see FIG. 7B), and the current flowing through the motor 11a (FIG. 7C). It is an experimental result which shows the change of reference.
As described above, by alternately repeating the “first state” and the “second state” (S103: see FIG. 3), the amplitude of the current flowing through the motor 11a is suppressed to less than the predetermined value I1. (See FIG. 7C). This is because in the “second state” in which the switching elements S1 to S6 are turned off, fluctuations in the induced voltage generated in the windings gu, gv, and gw are suppressed. Therefore, according to the present embodiment, it is possible to suppress reverse rotation after the motor 11a is stopped while preventing demagnetization of a permanent magnet (not shown) included in the motor 11a and occurrence of defects in the switching elements S1 to S6. .
　また、モータ１１ａに流れる電流の振幅が比較的小さいため（図７（ｃ）参照）、モータ１１ａの停止直後において、モータ１１ａのトルクの変動幅が（図７（ｂ）参照）、比較例（図１１（ｂ）参照）よりも小さくなっている。したがって、本実施形態によれば、モータ１１ａのトルク変動に起因する唸り音や振動を抑制できる。 Further, since the amplitude of the current flowing through the motor 11a is relatively small (see FIG. 7C), the fluctuation range of the torque of the motor 11a immediately after the stop of the motor 11a (see FIG. 7B) is shown as a comparative example ( It is smaller than that shown in FIG. Therefore, according to the present embodiment, it is possible to suppress the roaring sound and vibration caused by the torque fluctuation of the motor 11a.
　図８は、第１実施形態及び比較例における圧縮機１１の運転効率を示す説明図である。
　図８の横軸は、モータ１１ａの回転速度であり、縦軸は、圧縮機１１の運転効率である。
　なお、比較例（破線）は、モータ１１ａの逆回転を規制する逆止弁（図示せず）を圧縮機１１に設けた構成の空気調和機である。 FIG. 8 is an explanatory diagram showing the operating efficiency of the compressor 11 in the first embodiment and the comparative example.
The horizontal axis of FIG. 8 is the rotational speed of the motor 11a, and the vertical axis is the operating efficiency of the compressor 11.
The comparative example (broken line) is an air conditioner having a configuration in which a check valve (not shown) that restricts reverse rotation of the motor 11a is provided in the compressor 11.
　図８に示すように、圧縮機１１の運転領域である回転速度Ｎ１～Ｎ２の全範囲において、比較例よりも本実施形態のほうが、圧縮機１１の運転効率が高くなっている。これは、逆止弁（図示せず）を設けない本実施形態のほうが、圧縮機１１における冷媒の圧力損失が小さいからである。また、本実施形態によれば、逆止弁を設ける必要がないため、圧縮機１１の部品点数を削減し、ひいては、空気調和機１００の製造コストを低減できる。 As shown in FIG. 8, the operation efficiency of the compressor 11 is higher in the present embodiment than in the comparative example in the entire range of the rotational speeds N1 to N2 that is the operation region of the compressor 11. This is because the pressure loss of the refrigerant in the compressor 11 is smaller in the present embodiment in which a check valve (not shown) is not provided. Moreover, according to this embodiment, since it is not necessary to provide a check valve, the number of parts of the compressor 11 can be reduced, and thus the manufacturing cost of the air conditioner 100 can be reduced.
≪第２実施形態≫
　第２実施形態は、圧縮機１１の停止時におけるスイッチング素子Ｓ１～Ｓ６のオン・オフの切替えの仕方が第１実施形態とは異なっているが、その他（空気調和機１００や電力変換装置３０の構成：図１、図２参照）については第１実施形態と同様である。したがって、第１実施形態とは異なる部分について説明し、重複する部分については説明を省略する。 << Second Embodiment >>
The second embodiment is different from the first embodiment in how the switching elements S1 to S6 are switched on and off when the compressor 11 is stopped, but the other (the air conditioner 100 and the power conversion device 30). The configuration (see FIGS. 1 and 2) is the same as in the first embodiment. Therefore, a different part from 1st Embodiment is demonstrated and description is abbreviate | omitted about the overlapping part.
　図９は、第２実施形態に係る電力変換装置３０の制御部３３が実行する処理のフローチャートである。
　ステップＳ２０１において制御部３３は、モータ１１ａを停止させるか否かを判定する。モータ１１ａを停止させない場合（Ｓ２０１：Ｎｏ）、制御部３３は、モータ１１ａを駆動させつつ、ステップＳ２０１の判定処理を繰り返す。一方、モータ１１ａを停止させる場合（Ｓ２０１：Ｙｅｓ）、制御部３３の処理はステップＳ２０２に進む。
　ステップＳ２０２において制御部３３は、「第１制御」と「第２制御」とを交互に繰り返す。なお、「第１制御」及び「第２制御」の説明については後記する。 FIG. 9 is a flowchart of processing executed by the control unit 33 of the power conversion device 30 according to the second embodiment.
In step S201, the control unit 33 determines whether to stop the motor 11a. When not stopping the motor 11a (S201: No), the control part 33 repeats the determination process of step S201, driving the motor 11a. On the other hand, when stopping the motor 11a (S201: Yes), the process of the control part 33 progresses to step S202.
In step S202, the control unit 33 alternately repeats “first control” and “second control”. The “first control” and “second control” will be described later.
　ステップＳ２０３において制御部３３は、ステップＳ２０２の制御の開始時から所定時間が経過したか否かを判定する。
　ステップＳ２０２の制御の開始時から所定時間が経過していない場合（Ｓ２０３：Ｎｏ）、制御部３３の処理はステップＳ２０２に戻る。一方、ステップＳ２０２の制御の開始時から所定時間が経過した場合（Ｓ２０３：Ｙｅｓ）、制御部３３は一連の処理を終了する（ＥＮＤ）。そして、図９では省略したが、制御部３３はスイッチング素子Ｓ１～Ｓ６をオフ状態にする。 In step S203, the control unit 33 determines whether a predetermined time has elapsed since the start of the control in step S202.
When the predetermined time has not elapsed since the start of the control in step S202 (S203: No), the process of the control unit 33 returns to step S202. On the other hand, when a predetermined time has elapsed from the start of the control in step S202 (S203: Yes), the control unit 33 ends the series of processes (END). Then, although omitted in FIG. 9, the control unit 33 turns off the switching elements S1 to S6.
　次に、ステップＳ２０２の「第１制御」について図１０（ａ）を参照して説明し、さらに、「第２制御」について図１０（ｂ）を参照して説明する。 Next, the “first control” in step S202 will be described with reference to FIG. 10 (a), and the “second control” will be described with reference to FIG. 10 (b).
　図１０（ａ）は、電力変換装置３０の「第１制御」の説明図である。
　「第１制御」において制御部３３は、モータ１１ａの巻線ｇｕ，ｇｖ，ｇｗと平滑キャパシタＣ（直流電源）とを電気的に接続するように、上アーム及び下アームのスイッチング素子Ｓ１～Ｓ６を制御する。図１０（ａ）に示す例では、制御部３３が、上アームのスイッチング素子Ｓ５、及び下アームのスイッチング素子Ｓ４をオン状態とし、他のスイッチング素子Ｓ１～Ｓ３，Ｓ６をオフ状態としている。これによって、平滑キャパシタＣの直流電圧がモータ１１ａの巻線ｇｕ，ｇｖ，ｇｗに印加され、モータ１１ａの逆回転を制動する力が発生する。 FIG. 10A is an explanatory diagram of “first control” of the power conversion device 30.
In the “first control”, the control unit 33 switches the switching elements S1 to S6 of the upper arm and the lower arm so as to electrically connect the windings gu, gv, gw of the motor 11a and the smoothing capacitor C (DC power supply). To control. In the example shown in FIG. 10A, the control unit 33 turns on the switching element S5 of the upper arm and the switching element S4 of the lower arm, and turns off the other switching elements S1 to S3 and S6. As a result, the DC voltage of the smoothing capacitor C is applied to the windings gu, gv, gw of the motor 11a, and a force for braking the reverse rotation of the motor 11a is generated.
　なお、「第１制御」において、例えば、スイッチング素子Ｓ２，Ｓ３をオン状態にし、他のスイッチング素子Ｓ１，Ｓ４～Ｓ６をオフ状態にしてもよい。 In the “first control”, for example, the switching elements S2 and S3 may be turned on, and the other switching elements S1, S4 to S6 may be turned off.
　図１０（ｂ）は、電力変換装置３０の「第２制御」の説明図である。
　「第２制御」において制御部３３は、上アームのスイッチング素子Ｓ１，Ｓ３，Ｓ５、及び下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６をオフ状態とする。その結果、モータ１１ａの巻線ｇｕ，ｇｖ，ｇｗのインダクタンスによって、モータ１１ａの逆回転を妨げる向きの還流電流が、還流ダイオードＤ等を介して流れる。したがって、この「第２制御」においても、モータ１１ａの逆回転が抑制される。なお、「第２制御」は、第１実施形態で説明した「第２の状態」（図４（ｂ）参照）と同様である。 FIG. 10B is an explanatory diagram of “second control” of the power conversion device 30.
In the “second control”, the control unit 33 turns off the switching elements S1, S3, and S5 of the upper arm and the switching elements S2, S4, and S6 of the lower arm. As a result, a return current in a direction that prevents reverse rotation of the motor 11a flows through the return diode D and the like due to the inductances of the windings gu, gv, and gw of the motor 11a. Therefore, also in the “second control”, the reverse rotation of the motor 11a is suppressed. The “second control” is the same as the “second state” (see FIG. 4B) described in the first embodiment.
　また、「第１制御」と「第２制御」とを交互に繰り返す過程で（Ｓ２０２：図９参照）、スイッチング素子Ｓ４，Ｓ５（図１０（ａ）参照）のオンデューティを増加させてもよい。これによって、特にモータ１１ａの駆動停止の直後における過渡的な電流変動やトルク変動を抑制できる。 Further, in the process of alternately repeating the “first control” and the “second control” (S202: see FIG. 9), the on-duty of the switching elements S4 and S5 (see FIG. 10 (a)) may be increased. . As a result, transient current fluctuations and torque fluctuations immediately after the motor 11a is stopped can be suppressed.
＜効果＞
　第２実施形態によれば、モータ１１ａの停止時に「第１制御」と「第２制御」とを繰り返すことで、圧縮機１１の吸込側・吐出側の差圧によるモータ１１ａの逆回転を抑制できる。また、モータ１１ａの電流変動やトルク変動を抑制できるため、モータ１１ａが備える永久磁石（図示せず）の減磁やスイッチング素子Ｓ１～Ｓ６の不具合を防止できる。また、モータ１１ａの逆回転に伴う唸り音や振動を抑制できる。 <Effect>
According to the second embodiment, by repeating the “first control” and the “second control” when the motor 11a is stopped, the reverse rotation of the motor 11a due to the differential pressure between the suction side and the discharge side of the compressor 11 is suppressed. it can. Further, since current fluctuation and torque fluctuation of the motor 11a can be suppressed, demagnetization of a permanent magnet (not shown) provided in the motor 11a and problems of the switching elements S1 to S6 can be prevented. Further, it is possible to suppress the roaring sound and vibration associated with the reverse rotation of the motor 11a.
≪変形例≫
　以上、本発明に係る電力変換装置３０について各実施形態で説明したが、本発明はこれらの記載に限定されるものではなく、種々の変更を行うことができる。
　例えば、第１実施形態では、「第１の状態」において制御部３３が、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６をオン状態とし（図４（ａ）参照）、上アームのスイッチング素子Ｓ１，Ｓ３，Ｓ５をオフ状態とする場合について説明したが（同図参照）、これに限らない。すなわち、「第１の状態」において制御部３３が、上アームのスイッチング素子Ｓ１，Ｓ３，Ｓ５をオン状態とし、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６をオフ状態としてもよい。なお、「第２の状態」（上アーム及び下アームのスイッチング素子Ｓ１～Ｓ６のオフ状態）については、第１実施形態と同様である。このような制御でも、第１実施形態と同様の効果が奏される。 ≪Modification≫
As mentioned above, although each embodiment demonstrated the power converter device 30 which concerns on this invention, this invention is not limited to these description, A various change can be performed.
For example, in the first embodiment, in the “first state”, the control unit 33 turns on the switching elements S2, S4, and S6 of the lower arm (see FIG. 4A), and switches the switching elements S1 and S1 of the upper arm. Although the case where S3 and S5 are set to the OFF state has been described (see the same figure), this is not restrictive. That is, in the “first state”, the control unit 33 may turn on the switching elements S1, S3, and S5 of the upper arm and turn off the switching elements S2, S4, and S6 of the lower arm. The “second state” (the OFF state of the switching elements S1 to S6 of the upper arm and the lower arm) is the same as in the first embodiment. Even with such control, the same effects as those of the first embodiment can be obtained.
　また、例えば、下アームのスイッチング素子Ｓ２，Ｓ４，Ｓ６をオン状態とする「第１の状態」、前記した「第２の状態」、上アームのスイッチング素子Ｓ１，Ｓ３，Ｓ５をオン状態とする「第１の状態」、及び「第２の状態」を順次に繰り返してもよい。 In addition, for example, the “first state” in which the switching elements S2, S4, S6 of the lower arm are turned on, the “second state” described above, and the switching elements S1, S3, S5 of the upper arm are turned on. The “first state” and the “second state” may be repeated sequentially.
　また、第１実施形態では、「第１の状態」において制御部３３が、下アームの全てのスイッチング素子Ｓ２，Ｓ４，Ｓ６をオン状態とする場合について説明したが、これに限らない。例えば、「第１の状態」において下アームのスイッチング素子Ｓ２，Ｓ４をオン状態とし、他のスイッチング素子Ｓ１，Ｓ３，Ｓ５，Ｓ６をオフ状態としてもよい。つまり、制御部３３が、モータ１１ａの停止時に、上アーム及び下アームのうち一方のスイッチング素子の少なくとも２つをオン状態とし、他方のスイッチング素子をオフ状態とする「第１の状態」と、上アーム及び下アームのスイッチング素子Ｓ１～Ｓ６をオフ状態とする「第２の状態」と、を交互に繰り返すようにしてもよい。このような制御でも、モータ１１ａの電流変動やトルク変動を抑制できる。 In the first embodiment, the case where the control unit 33 turns on all the switching elements S2, S4, and S6 of the lower arm in the “first state” has been described. However, the present invention is not limited to this. For example, in the “first state”, the switching elements S2 and S4 of the lower arm may be turned on, and the other switching elements S1, S3, S5, and S6 may be turned off. That is, when the motor 11a is stopped, the control unit 33 turns on at least two of the switching elements of one of the upper arm and the lower arm and turns off the other switching element; The “second state” in which the switching elements S1 to S6 of the upper arm and the lower arm are turned off may be alternately repeated. Even with such control, current fluctuation and torque fluctuation of the motor 11a can be suppressed.
　また、モータ１１ａの駆動中に電流検出部３２の検出値が所定値以上になった場合、制御部３３が、第１実施形態で説明した「第１の状態」と「第２の状態」とを交互に繰り返すことによって、モータ１１ａを停止させるようにしてもよい。これによって、モータ１１ａに過負荷がかかっている場合や、モータ１１ａの永久磁石が減磁し得る過電流が流れている場合に、その逆回転を抑制しつつモータ１１ａを停止できる。なお、前記した制御は、第２実施形態にも適用できる。 Further, when the detection value of the current detection unit 32 becomes equal to or greater than a predetermined value during the driving of the motor 11a, the control unit 33 determines that the “first state” and the “second state” described in the first embodiment. Alternatively, the motor 11a may be stopped by repeating the above. As a result, when the motor 11a is overloaded or when an overcurrent that can demagnetize the permanent magnet of the motor 11a flows, the motor 11a can be stopped while suppressing reverse rotation. The control described above can also be applied to the second embodiment.
　また、各実施形態では、モータ１１ａが三相モータである構成について説明したが、これに限らない。例えば、単相モータにも各実施形態を適用できる。
　また、各実施形態では、電力変換装置３０を圧縮機１１のモータ１１ａの制御に適用する場合について説明したが、これに限らない。すなわち、モータの停止時に、吸込側・吐出側における流体の差圧でモータが逆回転するような構成の他の機器（例えば、ポンプ）にも、各実施形態を適用できる。 Moreover, although each embodiment demonstrated the structure where the motor 11a is a three-phase motor, it is not restricted to this. For example, each embodiment can be applied to a single-phase motor.
Moreover, although each embodiment demonstrated the case where the power converter device 30 was applied to control of the motor 11a of the compressor 11, it is not restricted to this. That is, each embodiment can also be applied to other devices (for example, pumps) configured such that when the motor is stopped, the motor rotates in reverse by the pressure difference between the suction side and the discharge side.
　また、各実施形態ではスクロール型の圧縮機１１を用いる場合について説明したが、これに限らない。すなわち、圧縮機１１の停止時に吸込側・吐出側で差圧が生じ、この差圧によってモータ１１ａが逆回転するという特性を有していれば、他の種類の圧縮機（例えば、ヘリカル型の圧縮機）にも本実施形態を適用できる。 In each embodiment, the case where the scroll compressor 11 is used has been described. However, the present invention is not limited to this. That is, if the compressor 11 has a characteristic that a differential pressure is generated on the suction side and the discharge side when the compressor 11 is stopped and the motor 11a rotates in reverse due to the differential pressure, other types of compressors (for example, a helical type) The present embodiment can also be applied to a compressor.
　また、各実施形態では、Ｕ相・Ｖ相・Ｗ相の配線に電流検出部３２（図２参照）を設ける構成について説明したが、これに限らない。例えば、直流側の母線にシャント抵抗（図示せず）を設け、制御部３３が、このシャント抵抗に流れる電流の検出値に基づいて、スイッチング素子Ｓ１～Ｓ６のオン・オフを制御するようにしてもよい。 In each embodiment, the configuration in which the current detection unit 32 (see FIG. 2) is provided in the U-phase, V-phase, and W-phase wirings is described, but the present invention is not limited to this. For example, a shunt resistor (not shown) is provided on the DC bus, and the control unit 33 controls on / off of the switching elements S1 to S6 based on the detected value of the current flowing through the shunt resistor. Also good.
　また、各実施形態では、空気調和機１００が四方弁１５を備える構成について説明したが、これに限らない。すなわち、四方弁１５を省略し、冷房専用又は暖房専用の空気調和機にしてもよい。 Moreover, although each embodiment demonstrated the structure with which the air conditioner 100 was provided with the four-way valve 15, it is not restricted to this. That is, the four-way valve 15 may be omitted, and an air conditioner dedicated to cooling or heating may be used.
　また、各実施形態は本発明を分かりやすく説明するために詳細に記載したものであり、必ずしも説明した全ての構成を備えるものに限定されない。また、各実施形態の構成の一部について、他の構成の追加・削除・置換をすることが可能である。
　また、前記した機構や構成は説明上必要と考えられるものを示しており、製品上必ずしも全ての機構や構成を示しているとは限らない。 Each embodiment is described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the described configurations. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.
In addition, the above-described mechanisms and configurations are those that are considered necessary for the description, and do not necessarily indicate all the mechanisms and configurations on the product.
　１００　空気調和機
　１０　　冷媒回路
　１１　　圧縮機
　１１ａ　モータ
　１２　　室外熱交換器（凝縮器、蒸発器）
　１３　　膨張弁
　１４　　室内熱交換器（蒸発器、凝縮器）
　１５　　四方弁
　３０　　電力変換装置
　３１　　電力変換部
　３１ａ　ブリッジ回路
　３１ｂ　ゲート・ドライバ
　３２　　電流検出部
　３３　　制御部
　３３ａ　インバータ制御部
　３３ｂ　パルス制御部
　２０　　コンバータ部（直流電源）
　Ｃ　　　平滑キャパシタ（直流電源）
　Ｆ２　　室内ファン
　Ｓ１，Ｓ３，Ｓ５　スイッチング素子（上アームのスイッチング素子）
　Ｓ２，Ｓ４，Ｓ６　スイッチング素子（下アームのスイッチング素子）
　ｇｕ，ｇｖ，ｇｗ　巻線 DESCRIPTION OF SYMBOLS 100 Air conditioner 10 Refrigerant circuit 11 Compressor 11a Motor 12 Outdoor heat exchanger (condenser, evaporator)
13 Expansion valve 14 Indoor heat exchanger (evaporator, condenser)
DESCRIPTION OF SYMBOLS 15 Four way valve 30 Power converter 31 Power converter 31a Bridge circuit 31b Gate driver 32 Current detection part 33 Control part 33a Inverter control part 33b Pulse control part 20 Converter part (DC power supply)
C Smoothing capacitor (DC power supply)
F2 Indoor fan S1, S3, S5 Switching element (Upper arm switching element)
S2, S4, S6 Switching element (lower arm switching element)
gu, gv, gw winding

Claims (8)

  1. 　直流電源の正側に接続される上アームの複数のスイッチング素子を有するとともに、前記直流電源の負側に接続される下アームの複数のスイッチング素子を有し、前記直流電源から印加される直流電圧をモータの駆動電圧に変換する電力変換部と、
    　前記モータの停止時に、前記上アーム及び前記下アームのうち一方の前記スイッチング素子の少なくとも２つをオン状態とし、他方の前記スイッチング素子をオフ状態とする第１の状態と、前記上アーム及び前記下アームの前記スイッチング素子をオフ状態とする第２の状態と、を交互に繰り返す制御部と、を備えること
    　を特徴とする電力変換装置。     DC voltage applied from the DC power supply, having a plurality of switching elements of the upper arm connected to the positive side of the DC power supply and a plurality of switching elements of the lower arm connected to the negative side of the DC power supply A power converter that converts the motor to a motor drive voltage;
    A first state in which at least two of the switching elements of the upper arm and the lower arm are turned on and the other switching element is turned off when the motor is stopped; and the upper arm and the A power conversion device comprising: a control unit that alternately repeats a second state in which the switching element of the lower arm is turned off.
  2. 　前記制御部は、前記第１の状態と前記第２の状態とを交互に繰り返す過程で、前記少なくとも２つの前記スイッチング素子のオンデューティを増加させること
    　を特徴とする請求項１に記載の電力変換装置。     2. The power conversion according to claim 1, wherein the control unit increases an on-duty of the at least two switching elements in a process of alternately repeating the first state and the second state. apparatus.
  3. 　前記制御部は、前記第１の状態と前記第２の状態とを交互に繰り返す制御を所定時間行った後、前記第１の状態を継続させること
    　を特徴とする請求項１に記載の電力変換装置。     2. The power conversion according to claim 1, wherein the control unit continues the first state after performing a control for repeating the first state and the second state alternately for a predetermined time. apparatus.
  4. 　前記制御部は、前記第１の状態と前記第２の状態とを交互に繰り返す前に、前記直流電源に含まれるコンバータ部の昇圧動作を停止させること
    　を特徴とする請求項１に記載の電力変換装置。     2. The electric power according to claim 1, wherein the control unit stops the boosting operation of a converter unit included in the DC power supply before alternately repeating the first state and the second state. Conversion device.
  5. 　前記モータの巻線に流れる電流を検出する電流検出部を備え、
    　前記制御部は、前記モータの駆動中に前記電流検出部の検出値が所定値以上になった場合、前記第１の状態と前記第２の状態とを交互に繰り返すことによって前記モータを停止させること
    　を特徴とする請求項１に記載の電力変換装置。     A current detection unit for detecting a current flowing in the winding of the motor;
    The control unit stops the motor by alternately repeating the first state and the second state when the detection value of the current detection unit becomes a predetermined value or more during driving of the motor. The power converter according to claim 1, wherein:
  6. 　請求項１から請求項５のいずれか一項に記載の電力変換装置を備えるとともに、
    　前記モータによって駆動する圧縮機と、凝縮器と、膨張弁と、蒸発器と、が環状に順次接続されてなる冷媒回路を備えること
    　を特徴とする空気調和機。     While comprising the power conversion device according to any one of claims 1 to 5,
    An air conditioner comprising a refrigerant circuit in which a compressor driven by the motor, a condenser, an expansion valve, and an evaporator are sequentially connected in an annular manner.
  7. 　直流電源の正側に接続される上アームの複数のスイッチング素子を有するとともに、前記直流電源の負側に接続される下アームの複数のスイッチング素子を有し、前記直流電源から印加される直流電圧をモータの駆動電圧に変換する電力変換部と、
    　前記モータの停止時に、前記モータの巻線と前記直流電源とを電気的に接続するように前記上アーム及び前記下アームの前記スイッチング素子を制御する第１制御と、前記上アーム及び前記下アームの前記スイッチング素子をオフ状態にする第２制御と、を交互に繰り返す制御部と、を備えること
    　を特徴とする電力変換装置。     DC voltage applied from the DC power supply, having a plurality of switching elements of the upper arm connected to the positive side of the DC power supply and a plurality of switching elements of the lower arm connected to the negative side of the DC power supply A power converter that converts the motor to a motor drive voltage;
    A first control for controlling the switching elements of the upper arm and the lower arm so as to electrically connect the winding of the motor and the DC power source when the motor is stopped; and the upper arm and the lower arm And a control unit that alternately repeats the second control for turning off the switching element.
  8. 　請求項７に記載の電力変換装置を備えるとともに、
    　前記モータによって駆動する圧縮機と、凝縮器と、膨張弁と、蒸発器と、が環状に順次接続されてなる冷媒回路を備えること
    　を特徴とする空気調和機。     While comprising the power conversion device according to claim 7,
    An air conditioner comprising a refrigerant circuit in which a compressor driven by the motor, a condenser, an expansion valve, and an evaporator are sequentially connected in an annular manner.
PCT/JP2017/030195 2016-09-05 2017-08-23 Power conversion device and air conditioner equipped with same WO2018043258A1 (en)

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JPS63206188A (en) * 1987-02-19 1988-08-25 Matsushita Electric Ind Co Ltd Protective device of brushless motor
JPH09140184A (en) * 1995-11-09 1997-05-27 Matsushita Electric Ind Co Ltd Driver for brushless motor
JP2008061404A (en) * 2006-08-31 2008-03-13 Daikin Ind Ltd Power conversion equipment
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