JP6739654B2 - Electric motor drive device and refrigeration cycle device - Google Patents

Description

The present invention relates to a drive device for an electric motor and a refrigeration cycle device including the same.

Conventionally, as described in Patent Document 1, there has been a drive device for an electric motor in which the connection state of one stator winding is fixed by either Y connection (star connection in Patent Document 1) or Δ connection. .. As for the connection state of the stator winding, the Δ connection is suitable when driving the electric motor at a high rotation speed. On the other hand, when the electric motor is driven at a low rotation speed, the Y connection is suitable. However, the electric motor whose connection state is fixed cannot be operated in a connection state suitable for the case where the rotation speed of the electric motor is changed. Therefore, in the drive device described in Patent Document 1, the electric motor includes a plurality of stator windings, and the connection state of the stator windings is switched to Y connection or Δ connection. This drive device is connected to a plurality of stator windings of the electric motor via terminals.

JP, 2008-228513, A

Since the driving device as described above is connected to the plurality of stator windings of the electric motor, the number of terminals to be connected is larger than that of the driving device of the electric motor whose connection state is fixed. For this reason, the worker may forget to connect the wiring to the terminal, or the wiring may come off from the terminal while driving the electric motor, so that the connection of the terminal may not be appropriate. If there is a wiring abnormality due to such terminal connection, the electric motor cannot be driven. However, when the electric motor does not drive, it is not possible for the operator or user to know whether there is a wiring error or whether the product is faulty due to another error, and appropriate measures for driving the electric motor cannot be taken. There was a problem that I could not.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a drive device for an electric motor that can recognize that there is a wiring abnormality.

A drive device for an electric motor according to the present invention,
An inverter that applies an AC voltage to the plurality of stator windings included in the electric motor,
A switching unit that switches the connection state of the plurality of stator windings,
A detection unit that detects a voltage applied to one stator winding among the plurality of stator windings via the switching unit;
The control unit outputs a signal for notifying that the connection between the inverter and the electric motor is abnormal based on the voltage detected by the detection unit to the notification unit.

According to the drive device for an electric motor of the present invention, when the DC bus voltage applied by the inverter and the voltage detected by the detector are different from each other, the wiring abnormality is notified, so that the worker or the user can confirm that there is a wiring abnormality. I can figure it out.

1 is a schematic configuration diagram showing a schematic configuration of an electric motor and a drive device according to Embodiment 1. Block diagram showing the configuration of the control unit in the first embodiment 1 is a schematic configuration diagram showing a Y connection state of an electric motor according to Embodiment 1. FIG. 1 is a schematic configuration diagram showing a Δ connection state of an electric motor according to Embodiment 1. FIG. Flowchart showing the operation of the control unit in the first embodiment FIG. 3 is a diagram showing a relationship between a drive signal output from a control unit and an input signal input in Embodiment 1. Flowchart showing the operation of the control unit in the first embodiment Flowchart showing the operation of the control unit in the first embodiment Flowchart showing the operation of the control unit in the second embodiment FIG. 4 is a diagram showing a relationship between a drive signal output by a control unit and an input signal input in Embodiment 2. Flowchart showing the operation of the control unit in the second embodiment Flowchart showing the operation of the control unit in the second embodiment A schematic configuration diagram showing a schematic configuration of an electric motor and a drive device according to a third embodiment.

Embodiment 1.
Hereinafter, an air conditioner 1 will be described as an example of a drive device 100 for an electric motor according to the present invention and a refrigeration cycle device 2 including the drive device 100. FIG. 1 is a diagram showing a schematic configuration of a drive device 100 and an air conditioner 1 according to Embodiment 1 of the present invention. The air conditioner 1 includes a drive device 100, a compressor 220, a flow path switching valve 300, an outdoor heat exchanger 310, an expansion valve 320, and an indoor heat exchanger 330. Among the constituent elements of the air conditioner 1, the indoor heat exchanger 330 is provided in the indoor unit, and the remaining constituent elements are provided in the outdoor unit.

The compressor 220, the flow path switching valve 300, the outdoor heat exchanger 310, the expansion valve 320, and the indoor heat exchanger 330 form a refrigerant circuit by being connected via a refrigerant pipe.
The compressor 220 includes an electric motor 200 and a compression unit 210. The electric motor 200 and the driving device 100 are connected to the terminals U1, U2, V1, V2, W1 and W2 by connecting wires.

The driving device 100 is connected to the AC power supply 10, receives AC power from the AC power supply 10, and drives the electric motor 200. The drive device 100 includes a reactor 20, a rectification unit 30, a capacitor 40, an inverter 50, a switching unit 60, a detection unit 70, a voltage detector 81, a current detector 82, and a hardware component such as an electronic printed circuit board. The controller 90 is provided.

The rectifier unit 30 is configured by connecting rectifiers 31, 33 such as diodes connected in series in parallel with the rectifiers 32, 34. A capacitor 40 is connected in parallel with the rectifying unit 30.

The inverter 50 includes switching elements 51 to 56 and a rectifier that is connected in antiparallel with the switching elements 51 to 56. The switching elements 51 to 56 are made of a wide-gap semiconductor, and are made of, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semiconductor Field Transistor) using SiC (silicon carbide). When a MOSFET is used, the parasitic diode is structurally provided, so that the same effect can be obtained without intentionally connecting the freewheeling diodes in parallel.

In the inverter 50, a series connection circuit of U-phase switching elements 51 and 54, a series connection circuit of V-phase switching elements 52 and 55, and a series connection circuit of W-phase switching elements 53 and 56 are provided in the rectifying unit 30, respectively. Are connected in parallel. Here, the switching elements 51 to 53 provided on the high potential side of the inverter 50, that is, on the anode side of the commutators 31 and 32 are switching elements of the upper arm. The switching elements 54 to 56 provided on the low potential side of the inverter 50, that is, on the cathode sides of the rectifiers 33 and 34 are the switching elements of the lower arm. A connection point 501 is provided between the switching element 51 and the switching element 54 and is connected to the terminal U1. A connection point 502 is provided between the switching element 52 and the switching element 55 and is connected to the terminal V1. A connection point 503 is provided between the switching element 53 and the switching element 56 and is connected to the terminal W1.

The electric motor 200 includes, as a plurality of stator windings, a U-phase stator winding, a V-phase stator winding, and a W-phase stator winding. In the following description, each stator winding will be referred to as a U-phase winding 201, a V-phase winding 202, and a W-phase winding 203. The terminal on the input side of the U-phase winding is terminal Ui and the terminal on the output side is terminal Uo. Further, the input side terminal of the V-phase winding is terminal Vi, the output side terminal is terminal Vo, the input side terminal of the W phase winding is terminal Wi, and the output side terminal is terminal Wo. Wiring can be detachably attached to the terminals Ui, Uo, Vi, Vo, Wi, and Wo.

The switching unit 60 includes switching devices 61 to 63 that are a plurality of switches. The switches 61 to 63 are c-contact type relays having three contacts a, b, and c.
The contacts a of the switches 61 to 63 are connected to each other at a connection point 600 of the Y connection. The contact b of the switch 61 is connected between the connection point 502 and the terminal Vi. The contact c of the switch 61 is connected to the terminal Uo via the terminal U2. Further, the contact b of the switch 62 is connected between the connection point 503 and the terminal Wi. The contact c of the switch 62 is connected to the terminal Vo via the terminal V2. The contact b of the switch 63 is connected between the connection point 501 and the terminal Ui. The contact c of the switch 63 is connected to the terminal Wo via the terminal W2. The switches 61 to 63 switch the connection state of the stator winding by connecting the contact point c and the contact point a or the contact point c and the contact point b.

The detection unit 70 includes a resistor 71, a resistor 72, a diode 73, and a capacitor 74. One end of the resistor 71 is connected to the electric motor 200 via the connection point 600, and the other end of the resistor 71 is in contact with the resistor 72. The connection point of the resistors 71 and 72 is connected to the control unit 90. Further, a diode 73 and a capacitor 74 connected in series are provided between the resistors 71 and 72 and the control unit 90. The anode side of the diode 73 is connected to the capacitor 74, and the cathode side is connected to the control unit 90. Further, one end of the capacitor 74 is connected to GRD.

The voltage detector 81 is connected to the upper arm and the lower arm of the inverter 50.
The current detector 82 is connected to the upper arm of the inverter 50. The current detector 82 may be any device that can detect a current, and has a configuration using a resistor and an amplifier, or a configuration using a current sensor.

The notification unit 94 is connected to the drive device 100. The notification unit 94 is a remote controller that operates the air conditioner 1. Information on wiring abnormality can be displayed in characters on the screen of the remote controller.

Next, the configuration of the control unit 90 will be described based on FIG. FIG. 2 is a block diagram showing the configuration of the control unit 90. The control unit 90 includes an inverter control unit 91, a switching control unit 92, and a wiring abnormality detection unit 93. The control unit 90 can be configured by a discrete system such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), or a microcomputer, for example.

The motor drive device 100 and the motor 200 as described above are connected via a plurality of terminals U1, U2, V1, V2, W1 and W2.

Next, the connection state of the stator winding will be described. FIG. 3 is a schematic configuration diagram showing a Y connection state of the electric motor 200 in the first embodiment, and FIG. 4 is a schematic configuration diagram showing a Δ connection state. The stator winding is switched to Y connection or Δ connection by the switching unit 60.
First, the Y connection state will be described. When the control unit 90 outputs the switching signal of the Y connection command, the switches 61 to 63 are in the a-c conduction state in which the contact points a and c are in conduction. As a result, as shown in FIG. 3, the terminal Uo of the U-phase winding 201, the terminal Vo of the V-phase winding 202, and the terminal Wo of the W-phase winding 203 are connected, that is, the Y-connection state. The connection point 600 is a neutral point where the U-phase winding 201, the V-phase winding 202, and the W-phase winding 203 are connected in the Y connection state.
Next, the Δ connection state will be described. When the control unit 90 outputs the switching signal for the Δ connection command, the switches 61 to 63 are in the b-c conduction state in which the contact points b and c are in conduction. As a result, as shown in FIG. 4, the terminal Uo is connected to the terminal Vi, the terminal Vo is connected to the terminal Wi, and the terminal Wo is connected to the terminal Ui, that is, the Δ connection state is established.

A case where the connection state of the stator winding is switched to the Y connection or the Δ connection will be described. As the connection state of the stator winding, a suitable state is selected from the relationship between the operating frequency of the air conditioner 1 and the efficiency. Specifically, the Δ connection is selected when the operating frequency of the air conditioner 1 is equal to or higher than the set frequency fx, and the Y connection is selected when the operating frequency is less than the frequency fx.

The line voltage of the Y-connected electric motor 200 is defined as VY, and the current flowing through the Y-connected electric motor 200 is defined as IY. Further, the line voltage of the Δ-connected electric motor 200 is defined as VΔ, and the current flowing through the Δ-connected electric motor 200 is defined as IΔ. Then, the relations of VY=√3×VΔ and √3×IY=IΔ are obtained. That is, the Δ connection has a larger current than the Y connection, but the voltage required for driving can be lowered.

A brushless DC motor using a permanent magnet is widely used for the rotor that constitutes the electric motor 200. When such a motor is used, the counter electromotive voltage increases as the rotation speed increases, and the voltage required for driving increases. When the Y-connected electric motor 200 is driven when the electric motor 200 is driven at a high rotational speed, the required voltage is higher than the Δ connection, so that the magnetic force of the permanent magnet is reduced, or the stator winding is unwound. It is necessary to take measures to reduce the counter electromotive voltage. If such measures are taken, the current flowing through the electric motor 200 and the inverter 50 increases, and the energy conversion efficiency decreases. Therefore, when driving the electric motor 200 at a high rotation speed, the winding state of the electric motor 200 is switched from the Y connection to the Δ connection. As a result, the voltage required to drive the electric motor 200 becomes 1/√3, so that the operation can be continued without taking measures to reduce the counter electromotive voltage.

On the other hand, when the electric motor 200 is driven at a low rotation speed, the current value can be reduced to 1/√3 as compared with the Δ connection by using the Y connection. Further, since the operation is performed in the Y connection state only when the rotation speed is low, the output current value can be made smaller than that in the case where the connection state is fixed and the entire rotation speed range is operated in the Y connection state. As a result, the loss of the inverter 50 can be reduced, which can contribute to the high efficiency of energy conversion.

Next, the operation of the air conditioner 1 will be described.
The compressor 220 compresses the sucked low-pressure refrigerant and discharges it as high-pressure refrigerant.
The outdoor heat exchanger 310 exchanges heat between the refrigerant and the outdoor air, and functions as a condenser during cooling operation and as an evaporator during heating operation.
The indoor heat exchanger 330 exchanges heat between the refrigerant and the indoor air, and functions as an evaporator during cooling operation and as a condenser during heating operation.
The expansion valve 320 decompresses the high-pressure refrigerant into a low-pressure refrigerant. As the expansion valve 320, for example, an electromagnetic expansion valve whose opening can be adjusted is used.
The passage switching valve 300 switches the passage of the refrigerant flowing inside the refrigerant passage between the cooling operation and the heating operation.

Next, the operations of the electric motor 200 and the drive device 100 will be described. When the electric motor 200 is driven, an AC voltage is applied from the AC power supply 10.
The rectifying unit 30 and the capacitor 40 convert the applied AC voltage into a DC voltage.

The voltage detector 81 detects the DC bus voltage input to the inverter 50.
The current detector 82 detects the DC bus current input to the inverter 50.

The switching elements 51 to 56 of the inverter 50 convert a DC voltage into a three-phase AC voltage by repeating on/off based on a drive signal sent from an inverter control unit 91 described later. When the switching elements 51 to 56 are on, the switching elements 51 to 56 are in a state of connecting the AC power supply 10 and the electric motor 200. When the switching elements 51 to 56 are off, the switching elements 51 to 56 do not connect the AC power supply 10 and the electric motor 200.

The switching unit 60 switches the connection state of the U-phase winding 201, the V-phase winding 202, and the W-phase winding 203 to a Y connection or a Δ connection based on a switching signal sent from a switching control unit 92 described later.

The detection unit 70 detects the voltage applied to one of the U-phase winding 201, the V-phase winding 202, and the W-phase winding 203 via the switching unit 60. When the voltage applied to the stator winding is higher than the voltage that can be input to the control unit 90, if the voltage is directly input to the control unit 90, the control unit 90 will fail. In order to prevent a failure, the voltage divided by the resistors 71 and 72 is input to the control unit 90. The resistors 71 and 72 select resistance values that do not cause the control unit 90 to fail. With this configuration, the voltage divided from the potential at the connection point between the resistors 71 and 72 is input to the control unit 90.
The voltage that can be input to the control unit 90 is, for example, 5V. However, if noise or the like occurs, the voltage divided by the resistors 71 and 72 may be higher than 5V. At this time, since a current flows through the diode 73 and the capacitor 74, the voltage input to the control unit 90 becomes smaller than 5 V, and the control unit 90 is prevented from malfunctioning.

Next, the operation of the control unit 90 will be described. When the electric motor 200 is driven, the operating frequency of the air conditioner 1 is input to the control unit 90 from the outside.
The inverter control means 91 outputs to the inverter 50 a drive signal for applying a voltage to one stator winding. This drive signal is output based on the input operating frequency, the voltage detected by the voltage detector 81, the current detected by the current detector 82, or both the detected voltage and current. A PMW (Pulse Width Modulation) signal for driving the switching elements 51 to 56.
The inverter control means 91 detects the voltage and the current from the voltage detector 81 and the current detector 82, respectively, while the electric motor 200 is being driven. Then, the inverter control means 91 outputs to the inverter 50 a drive signal that converts the detected voltage and current into the voltage and current required to output the target operating frequency.

The switching control unit 92 outputs a switching signal for switching the connection state of the U-phase winding 201, the V-phase winding 202, or the W-phase winding to the switching unit 60. When the input operating frequency is equal to or higher than the set frequency fx, the switching control means 92 outputs the switching signal for switching the switches 61 to 63 to the conduction between b and c to make the stator winding Δ-connected. When the input operating frequency is less than the set frequency fx, the switching control means 92 outputs a switching signal for switching the switches 61 to 63 to conduction between a and c, and makes the stator winding a Y connection.

The wiring abnormality detecting means 93 detects whether or not there is a wiring abnormality based on the voltage detected by the detection unit 70. The wiring abnormality is an abnormality relating to the connection between the electric motor 200 and the inverter 50 or the detection unit 70, and means that the terminal is not properly connected because the wiring is pulled out from the terminal. The wiring abnormality detecting means 93 detects the input signal at regular time intervals based on the voltage detected by the detecting section 70. The wiring abnormality detection means 93 determines that the input signal Lo has been input when the voltage detected by the detection unit 70 is the GND voltage. On the other hand, when the voltage detected by the detector 70 is the DC bus voltage, it is determined that the input signal Hi is input.
The fixed time interval is, for example, 250 μs, but the detection time can be changed according to the operating frequency of the air conditioner 1 to which the drive device 100 is adapted. When the wiring abnormality detecting unit 93 determines that there is a wiring abnormality, it outputs a notification signal to the notification unit 94 connected to the control unit 90.

Next, the operation of the control unit 90 for detecting a wiring abnormality will be described. The control unit 90 detects a wiring abnormality in the terminals U1, U2, Ui, and Uo connected to the U-phase winding 201, then detects the V-phase winding 202, and further detects the W-phase winding 203. First, the operation of the control unit 90 for detecting a wiring abnormality in the U-phase winding 201 will be described with reference to FIGS. 5 and 6. FIG. 5 is a flowchart showing the operation of the control unit 90. FIG. 6 is a diagram showing a relationship between the drive signal output from the inverter control means 91 and the input signal input to the wiring abnormality detection means 93 when the wiring abnormality is detected.

When the operation command for operating the electric motor 200 is received by remote control operation or the like, the control unit 90 starts the operation of detecting the wiring abnormality of the terminal. First, in step S10, the switching control means 92 outputs a switching signal that causes the switch 61 to conduct between a and c. When the switching signal is input, the switch 61 is conducted between a and c. Further, in step S11, the switching control means 92 outputs a switching signal for connecting the switches 62 and 63 between bc. When the switching signal is input, the switches 62 and 63 are conducted between bc. By the above switching operation, the U-phase winding 201 is connected to the connection point 600, whereby the inverter 50 is connected to the terminal U1, the terminal Ui, the U-phase winding 201, the terminal Uo, the terminal U2, the switching unit 61, and the detection unit 70. , And the control unit 90 are connected in this order. Since the V-phase winding 202 and the W-phase winding 203 are not conducted between a and c, no current flows.

Next, in step S12, the inverter control means 91 causes the drive signal for turning on the switching element 51 of the upper arm and the drive signal for turning off the switching element 54 of the lower arm connected to the terminal Ui of the U-phase winding 201. Is output. Further, it outputs a drive signal for turning off the switching elements 52, 53, 55, 56 other than the switching element connected to the terminal Ui of the U-phase winding 201. The time for turning on the switching element 51 is a preset set time Δt1. The set time Δt1 is set to a time longer than a fixed time interval in which the wiring abnormality detection means 93 detects the voltage of the detection unit 70. For example, when the fixed time interval is 250 μs, it is set to 2.5 times, which is 10 times. When the drive signal is input, as shown by Δt1 in FIG. 5, the switching element 51 of the inverter 50 is turned on and the switching element 54 is turned off. When the inverter 50 is driven, the process proceeds to step S13.

Here, the relationship between the operation of the switching elements 51 and 54 and the input signal will be described. When the wiring of the electric motor 200, the driving device 100, and the switching unit 60 is appropriate, when the switching element 51 of the upper arm is on, the DC bus voltage is applied to the U-phase winding 201. Therefore, the input signal Hi is input to the wiring abnormality detecting means 93.

In step S13, the wiring abnormality detecting means 93 determines whether or not the input signal Lo is input. In step S12, the switching element 51 of the upper arm is on and the switching element 54 of the lower arm is off, so that the input signal Hi is input to the wiring abnormality detecting means 93. That is, the input signal Lo is not input to the wiring abnormality detecting means 93 in the state where the connection is appropriate.

When the input signal Lo is not input in step S13 (step S13: No), the wiring abnormality detection unit 93 determines that the switching element 51 of the drive device 100 and the electric motor 200 are properly connected, and detects the wiring abnormality. End the operation.

When the input signal Lo is input in step S13 (step S13: Yes), the wiring abnormality detection means 93 determines that the connection between the inverter 50 and the electric motor 200 is abnormal, and proceeds to step S14. At this time, the voltage becomes the GND voltage because the connection of any of the terminals U1, U2, Ui, and Uo is incorrect or the terminal is disconnected, and the input signal Lo is input to the wiring abnormality detection means 93. That is, when the voltage is different from the DC bus voltage applied by the inverter 50, it is determined that the connection is abnormal.

In step S14, the wiring abnormality detection means 93 outputs a notification signal indicating the wiring abnormality to the notification unit 94. When the notification signal is input, the notification unit 94 displays in text that there is a wiring abnormality.

When the detection of the wiring abnormality in the U-phase winding 201 is completed, the detection of the wiring abnormality in the V-phase winding 202 is started. FIG. 7 is a flowchart showing the operation of detecting a wiring abnormality in the V-phase winding 202. In detecting the wiring abnormality in the V-phase winding 202 and the W-phase winding 203, the operations of the switchers 61 to 63 and the switching elements 51 to 56 are different from those in the case of the U-phase winding 201.

In step S20, the switch 62 is electrically connected between a and c. In step S21, the switches 61 and 63 are electrically connected between b and c. By this switching operation, the circuit is connected from the inverter 50 to the terminal V1, the terminal Vi, the V-phase winding 202, the terminal Vo, the terminal V2, the switch 62, the detector 70, and the controller 90 in this order.
In step S22, the inverter control means 91 turns on the switching element 52 of the upper arm and turns off the switching element 55 of the lower arm. Further, the switching elements 51, 53, 54 and 56 are turned off.

When the detection of the wiring abnormality in the V-phase winding 202 is completed, the detection of the wiring abnormality in the W-phase winding 203 is started. FIG. 8 is a flowchart showing the operation of detecting a wiring abnormality in the W-phase winding 203.

In step S30, the switch 63 is electrically connected between a and c. Further, in step S31, the switches 61 and 62 are electrically connected between b and c. By this switching operation, the circuit is connected in order from the inverter 50 to the terminal W1, the terminal Wi, the W-phase winding 203, the terminal Wo, the terminal W2, the switch 63, the detector 70, and the controller 90.
In step S32, the inverter control means 91 turns on the switching element 53 of the upper arm and turns off the switching element 56 of the lower arm. Further, the switching elements 51, 52, 54 and 55 are turned off.

In the driving apparatus 100 for the electric motor 200 according to the first embodiment as described above, when the input signal Lo is input to the wiring abnormality detection means 93 while the switching elements 51 to 53 of the upper arm are on, the notification unit It is displayed that 94 has a wiring abnormality. That is, when the DC bus voltage applied by the inverter 50 and the voltage detected by the detection unit 70 are different, a wiring abnormality is notified.

According to the drive device 100 of the electric motor 200 according to the first embodiment as described above, when the wiring of the terminal connecting the electric motor 200 and the drive device 100 is disconnected or there is a wiring abnormality due to improper terminal connection. Since the notification section 94 displays that there is a wiring abnormality, the worker or user can recognize that there is a wiring abnormality.

For example, when an operator detaches the terminal to install the product, the operator may forget to return the terminal or may mistake the terminal to be connected. If the wiring is not properly connected, the electric motor 200 does not operate, and the operator needs to find the cause of the inoperability and take an appropriate countermeasure. According to the drive device 100 of the first embodiment, the worker can recognize that there is a wiring abnormality, and therefore, it is possible to connect the detached terminal or repair the terminal in which the wiring is not properly connected.

If the cause of the non-operation of the electric motor 200 is abnormal wiring, it is not necessary to prepare tools or parts, and the connection of the terminals can be repaired. However, if it is not possible to detect that there is a wiring abnormality, tools and parts were prepared so that other abnormalities could be dealt with. According to the drive device 100 of the present invention, an operator can recognize that there is a wiring abnormality, and therefore, it is not necessary to prepare tools and equipment, and the connection of terminals can be easily corrected.

Further, since the wiring abnormality can be distinguished from the abnormality due to the failure of the component, it is not judged that the component is faulty and is not replaced even though the component is not faulty.

In addition, the user can inform the operator that the wiring is abnormal, so the operator needs to investigate the cause of the abnormality and prepare tools and parts to deal with other abnormalities. Absent.

Further, the switching unit 60 can be switched to detect wiring abnormality in one of the U-phase winding 201, the V-phase winding 202, and the W-phase winding 203. Therefore, it is possible to detect the wiring abnormality in the electric motor 200 having a larger number of terminals to be connected than in the electric motor driving device whose connection state is fixed.

Further, since the detection unit 70 is connected to the connection point 600 of the Y connection, one detection unit 70 can detect the wiring abnormality for the plurality of stator windings.

Further, in the state where one stator winding is connected to the connection point 600, a wiring abnormality is detected, so it is determined which one of the plurality of stator windings has a wiring abnormality. be able to.

Embodiment 2.
In the first embodiment, when the input signal Lo is input to the wiring abnormality detection means 93 while the switching elements 51 to 53 of the upper arm are on, it is determined that the connection between the inverter 50 and the driving device 100 is abnormal. It was judged. On the other hand, in the second embodiment, in addition to the operation of the first embodiment, when the input signal Hi is input to the wiring abnormality detecting means 93 in a state where the lower arm switching elements 54 to 56 are turned on, It is determined that the connection between the inverter 50 and the driving device 100 is abnormal. In the second embodiment, differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

After detecting the wiring abnormality in the U-phase winding 201, the control unit 90 detects the V-phase winding 202 and further detects the W-phase winding 203.
First, the operation of the control unit 90 detecting a wiring abnormality in the U-phase winding 201 will be described with reference to FIGS. 9 and 10. FIG. 9 is a flowchart showing the operation of the control unit 90. FIG. 10 is a diagram showing the relationship between the drive signal output from the inverter control means 91 and the input signal input to the wiring abnormality detection means 93 when the wiring abnormality is detected. In the second embodiment, the operations of steps S42 and S43 of FIG. 9 are added to the first embodiment.

In step S42, the inverter control means 91 outputs a drive signal for turning off the switching element 51 of the upper arm and a drive signal for turning on the switching element 54 of the lower arm. Further, it outputs a drive signal for turning off the switching elements 52, 53, 55, 56 other than the switching element connected to the terminal Ui of the U-phase winding 201. The time for turning on the switching element 54 is a preset set time Δt2. The set time Δt2 is set to a time longer than a fixed time interval in which the wiring abnormality detection means 93 detects the voltage of the detection unit 70. When the drive signal is input, as shown by Δt2 in FIG. 10, the switching element 51 of the inverter 50 is turned off and the switching element 56 is turned on. When the inverter 50 is driven, the process proceeds to step S43.

Here, the relationship between the operation of the switching elements 51 and 54 and the input signal will be described. When the wiring of the electric motor 200, the driving device 100, and the switching unit 60 is appropriate, the GND voltage is applied to the stator winding when the switching element 54 of the lower arm is on. Therefore, the input signal Lo is input to the wiring abnormality detecting means 93.

In step S43, the wiring abnormality detection means 93 determines whether or not Hi is input. In step S42, since the switching element 51 of the upper arm is in the off state and the switching element 54 of the lower arm is in the on state, the input signal Lo is input to the wiring abnormality detecting means 93. That is, the input signal Hi is not input to the wiring abnormality detecting means 93 in the state where the connection is appropriate.

When the input signal Hi is not input in step S43 (step S43: No), the wiring abnormality detection means 93 determines that the switching element 51 of the drive device 100 and the electric motor 200 are properly connected, and proceeds to step S44. ..

When the input signal Hi is input in step S43 (step S43: Yes), the wiring abnormality detection means 93 determines that the connection between the inverter 50 and the electric motor 200 is abnormal, and proceeds to step S46. At this time, any one of the terminals U1, U2, Ui, and Uo is erroneously connected or disconnected, so that the voltage becomes a voltage different from the GND voltage, and the input signal Hi is input to the wiring abnormality detecting means 93. That is, when the DC bus voltage applied by the inverter 50 and the voltage detected by the detection unit 70 are different, it is determined that the connection is abnormal.

The operations of steps S44, S45, and S46 are the same as the operations of steps S12, S13, and S14 in the first embodiment, respectively.

When the detection of the wiring abnormality in the U-phase winding 201 is completed, the detection of the wiring abnormality in the V-phase winding 202 is started. FIG. 11 is a flowchart showing the operation of detecting a wiring abnormality in the V-phase winding 202. In detecting the wiring abnormality in the V-phase winding 202 and the W-phase winding 203, the operations of the switchers 61 to 63 and the switching elements 51 to 56 are different from those in the case of the U-phase winding 201.

In step S50, the switch 62 is electrically connected between a and c. Further, in step S51, the switches 61 and 63 are electrically connected between b and c.
In step S52, the inverter control means 91 turns off the upper arm switching element 52 and turns on the lower arm switching element 55. Further, a drive signal for turning off the switching elements 51, 53, 54 and 56 is output.

When the detection of the wiring abnormality in the V-phase winding 202 is completed, the detection of the wiring abnormality in the W-phase winding 203 is started. FIG. 12 is a flowchart showing the operation of detecting a wiring abnormality in the W-phase winding 203.

In step S60, the switch 63 is electrically connected between a and c. In step S61, the switches 61 and 62 are electrically connected between b and c.
In step S62, the inverter control means 91 turns off the switching element 53 of the upper arm and turns on the switching element 56 of the lower arm. Further, a drive signal for turning off the switching elements 51, 52, 54, 55 is output.

In the drive device 100 of the electric motor 200 according to the second embodiment as described above, when the input signal Hi is input to the wiring abnormality detection means 93 while the switching elements 54 to 56 of the lower arm are turned on, the inverter 50. And that the connection of the drive device 100 is abnormal. That is, when the DC bus voltage applied by the inverter 50 and the voltage detected by the detection unit 70 are different, a wiring abnormality is notified.

According to drive device 100 of electric motor 200 according to Embodiment 1 described above, when there is a wiring abnormality due to improper connection of the wiring that connects electric motor 200 and drive device 100, the worker or user can It is possible to understand that there is a wiring abnormality.

In the drive device 100, the connection between the inverter 50 and the drive device 100 is abnormal when the switching elements 51 to 53 of the lower arm are on and the switching elements 54 to 56 of the upper arm are on. Make a decision. Therefore, it is possible to determine whether the wiring abnormality is an abnormality related to the switching elements 51 to 53 or an abnormality related to the switching elements 54 to 56.

In the second embodiment, the operation of turning on the switching elements 54 to 56 of the lower arm once and then turning on the switching elements 51 to 53 of the upper arm once is not limited to this. May be changed. Further, as the operation of turning on the switching elements 51 to 56, a case where each of the switching elements 51 to 56 is turned on once and a case where each of the switching elements 51 to 56 is turned on a plurality of times may be combined. Thereby, the operation for detecting the wiring abnormality can be changed according to the condition for driving the electric motor 200. For example, when the electric motor 200 is driven for the first time after the air conditioner 1 is installed, or when the possibility of wiring abnormality increases when the electric motor 200 is operated after a certain period of time, the switching elements 51 to 56 are selected. It can be turned on multiple times. Further, when the user repeatedly operates the air conditioner 1 for a short period of time, it is unlikely that a wiring abnormality will occur, so that the switching elements 51 to 56 can be turned on once.

Embodiment 3.
In the first embodiment, drive device 100 is one substrate, but in the third embodiment drive device 100 is composed of two substrates. FIG. 13 is a diagram showing a schematic configuration of the electric motor 200 and the driving device 110 according to the third embodiment of the present invention, and the configuration of the driving device 110 will be described based on FIG. In the third embodiment, differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

The drive device 110 includes a main circuit unit 111 and a circuit unit 112.
The main circuit unit 111 is connected to the AC power supply 10 and the reactor 20, and includes a rectifying unit 30, a capacitor 40, an inverter 50, a voltage detector 81, a current detector 82, and a control unit 90.
The circuit unit 112 includes a switching unit 60 and a detection unit 70.

The main circuit unit 111 and the circuit unit 112 are connected by connecting wires to the terminals U3, V3, W3, X3 connected to the main circuit unit 111 and the terminals U4, V4, W4, X4 connected to the circuit unit 112. The terminals U3 and U4 connect the U-phase winding 201 and the inverter 50. The terminals V3 and V4 connect the V-phase winding 202 and the inverter 50. The terminals W3 and W4 connect the W-phase winding 203 and the inverter 50. The terminals X3 and X4 connect the detection unit 70 and the control unit 90. The operation of the control unit 90 detecting the wiring abnormality is the same as the operation of the first embodiment.

The drive device 110 of the electric motor 200 according to the third embodiment as described above is in a state where the main circuit portion 111 and the circuit portion 112 are connected by a plurality of terminals and the switching elements 51 to 53 of the upper arm are on. When the input signal Lo is input to the wiring abnormality detection means 93, or when the input signal Hi is input to the wiring abnormality detection means 93 while the lower arm switching elements 54 to 56 are turned on, the inverter 50 and It informs that the connection of the drive device 100 is abnormal. That is, when the DC bus voltage applied by the inverter 50 and the voltage detected by the detection unit 70 are different, a wiring abnormality is notified.

According to the drive device 110 of the electric motor 200 according to the third embodiment as described above, when the drive device 110 is configured by the main circuit section 111 and the circuit section 112, it is possible that the worker or the user has a wiring abnormality. You can figure it out. In the drive device 110, a main circuit unit 111 that does not include the switching unit 60 that switches the connection state of the stator winding and a circuit unit 112 that includes the switching unit 60 are configured as different substrates. Therefore, the main circuit unit 111 can be manufactured as a common substrate for an electric motor in which the connection state is fixed and the switching unit 60 is unnecessary.
Further, when either the main circuit unit 111 or the circuit unit 112 fails, only the failed circuit unit can be replaced, so that the drive device 110 can be easily replaced.

Although the detection unit 70 is provided in the circuit unit 112 in the third embodiment, the present invention is not limited to this, and the detection unit 70 may be provided in the main circuit unit 111 or between the main circuit unit 111 and the circuit unit 1112. Is also good. Further, the driving device 120 is configured with two substrates, but the driving device 120 is not limited to this and may be configured with two or more substrates. Thereby, each board can be diverted as a board used for another electric motor 200.

Further, in the first to third embodiments, when the wiring abnormality detecting means 93 detects an input signal Lo or Hi different from the input signal Hi or Lo corresponding to the DC bus voltage applied by the inverter 50, the notification signal is issued. However, the notification signal may be output when the input signal is input a fixed number of times or when the input signal is input for a fixed time. The fixed number of times and the fixed time may be values preset in the driving device or values that can be set from the outside. By setting the number of inputs or the input time in this way, it is possible to prevent the notification signal from being output when the input signal is erroneously input to the wiring abnormality detection unit 93. Therefore, the accuracy of detecting the wiring abnormality can be improved.

Further, in order to detect the wiring abnormality, the switching elements 51 to 53 of the upper arm are turned on once, but the switching elements 51 to 53 may be turned on a plurality of times. By turning on the switching element a plurality of times, the number of times the wiring abnormality is detected increases, so that the accuracy can be improved.

Further, although the U-phase winding 201, the V-phase winding 202, and the W-phase winding 203 are arranged in the order of the stator windings for detecting the wiring abnormality, the order is not limited to this and the order may be changed.

Further, although the notification unit 94 is a remote controller that displays the information on the wiring abnormality in characters, the present invention is not limited to this, and it is sufficient that the notification unit 94 can notify that the wiring abnormality exists. For example, a light source such as an LED may be turned on or blinked, or a device for wireless communication such as a tablet terminal may be used. Further, it may be notified by sound. Therefore, the notification unit can be provided inside the product such as the outdoor unit of the air conditioner 1 or outside the product.

Further, as the material forming the commutators 31 to 34 and the switching elements 51 to 56, not only silicon (Si) but also wide band gap semiconductors such as silicon carbide (SiC), gallium nitride (GaN), and diamond are used. By using it, the energy loss can be further reduced.

Further, the switching unit 60 may use any method as long as it can switch the winding state of the electric motor 200. Therefore, the switchers 61 to 63 are not the c-contact type relays as shown in FIG. 1, but an operation similar to that of the switchers 61 to 63 in FIG. 1 can be realized by combining the a-contact and b-contact relays. You may comprise. Further, the switching unit 60 may be configured by a switching element using a connector such as an electromagnetic contactor or a semiconductor as long as it can switch the winding state of the electric motor 200. When a mechanical relay or the like is used, it is possible to reduce the conduction loss that occurs in the on-state when configured with a semiconductor, so that it is possible to obtain a more efficient motor drive device 100.

Although the voltage detector 81 is connected to the upper arm and the lower arm of the inverter 50, it may be connected to a position where the DC bus voltage input to the inverter 50 can be detected. For example, the voltage detector 81 may be provided at a position where the voltage divided by the resistor provided in parallel with the capacitor 40 is detected. Accordingly, the voltage of the capacitor 40, that is, the DC bus voltage on the input side of the inverter 50 may be converted into a voltage that can be detected by the control unit 90 and detected by the voltage detector 81.

Although the current detector 82 is connected to the upper arm of the inverter 50, it may be connected to a position where the DC bus current input to the inverter 50 can be detected. For example, the current detector 82 may detect a current flowing through the electric motor 200 by providing a sensor that detects a current between the inverter 50 and the electric motor 200.

The drive device 100 of the electric motor 200 according to the present invention can be widely used for a drive device of an electric motor for home use, commercial use, etc. and a refrigeration cycle application device.

10 AC power source, 20 reactor, 30 rectifier unit, 31, 32, 33, 34 commutator, 40, 74 capacitor, 50 inverter, 51, 52, 53, 54, 55, 56 switching element, 60 switching unit, 61, 62 , 63 switching unit, 70 detection unit, 71, 72 resistance, 73 diode, 81 voltage detector, 82 current detector, 90 control unit, 91 inverter control unit, 92 switching control unit, 93 wiring abnormality detection unit, 94 notification unit , 100, 110 drive device, 111 main circuit part, 112 circuit part, 200 electric motor, 201 U-phase winding, 202 V-phase winding, 203 W-phase winding, 210 compression part, 220 compressor, 300 flow path switching valve , 310 outdoor heat exchanger, 320 expansion valve, 330 indoor heat exchanger, 501, 502, 503, 600 connection point

Claims (10)

An inverter that applies an AC voltage to a plurality of stator windings included in the electric motor,
A switching unit for switching the connection state of the plurality of stator windings,
A detection unit that detects a voltage applied to one stator winding among the plurality of stator windings via the switching unit;
Said drive signal for applying the voltage to one stator winding has an inverter control means for outputting to the inverter, the voltage the inverter on the basis of the drive signal is detected by the voltage and the detection unit is applied and And a control unit that outputs a signal for notifying that the connection between the inverter and the electric motor is abnormal to the notifying unit, the drive device for the electric motor. The drive device for an electric motor according to claim 1, wherein the switching unit switches a connection state of the plurality of stator windings to a Y connection or a Δ connection. The drive device of the electric motor according to claim 2 , wherein the detection unit is connected to a neutral point of the Y connection. When the detection unit detects the voltage applied to the one stator winding, only one of the plurality of stator windings is connected to the neutral point. The drive device for the electric motor according to claim 3 . The drive of the electric motor according to any one of claims 1 to 4 , wherein the inverter includes an upper arm provided on a high potential side of the inverter and a lower arm provided on a low potential side of the inverter. apparatus. The control unit may output the signal to the notification unit when the detection unit detects the voltage on the high potential side of the inverter in a state where the lower arm is connected and a state where the upper arm is not connected. The drive device for the electric motor according to claim 5 . The control unit outputs the signal to the notification unit when the detection unit detects the voltage on the low potential side of the inverter while the upper arm is connected and the lower arm is not connected. The drive device for the electric motor according to claim 5 or 6 . The control unit outputs a drive signal that connects the lower arm and a drive signal that does not connect the upper arm, and then outputs a drive signal that connects the upper arm and a drive signal that does not connect the lower arm. The drive device for the electric motor according to claim 7 . The upper arm and the lower arm, the motor driving device according to any one of claims 5 to 8, characterized in that it is constituted by a wide band gap semiconductor. A refrigerant circuit through which the refrigerant flows,
An indoor heat exchanger that performs heat exchange between the refrigerant and indoor air,
An outdoor heat exchanger that performs heat exchange between the refrigerant and outdoor air,
A flow path switching valve that switches the flow path of the refrigerant flowing through the refrigerant circuit,
A compressor that compresses the refrigerant by driving the electric motor,
The compressor, the refrigeration cycle apparatus comprising: a drive braking system of electric motive according to any one of claims 1 to 9.

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