Motor drive device and air conditioner including the same

Abstract

A motor driving device and an air conditioner including the same are provided. The motor driving device includes an inverter provided with a plurality of switching devices, an alternating-current power source being output to a motor based on switching operations, a switching device configured between the inverter and the motor, converting a winding of the motor to a first connection method or a second connection method, and a control portion controlling the inverter and the switching device, the control portion limiting conversion of the connection method of the winding of the motor if a number of low-speed abnormal operations of the motor at a predetermined time with an operating frequency below a limit frequency exceeds a first critical value in a state of the second connection method.

Description

TECHNICAL FIELD

[0001] The present invention relates to a motor driving device and an air conditioner including the same, and more particularly, to a motor driving device preventing a failure of a winding switching device of a motor and an air conditioner including the same. BACKGROUND

[0002] An air conditioner is installed to provide a more comfortable indoor environment by blowing cold air or hot air into an indoor space, thereby adjusting the indoor temperature and purifying the indoor air. Generally, the air conditioner includes an indoor unit and an outdoor unit, the indoor unit is composed of a heat exchanger and is installed in an indoor space, and the outdoor unit is composed of a compressor and a heat exchanger and supplies refrigerant to the indoor unit.

[0003] On the other hand, in order to improve power conversion efficiency or motor driving efficiency when a compressor motor is driven in a compressor, an international patent application publication WO19-008756 (hereinafter, referred to as "prior art document") discloses a switching device that switches a winding of a motor using Y connection and Δ connection.

[0004] However, according to the prior art document, in order to switch the winding of the motor using Y connection or Δ connection, a mechanical switch or an electric switch as a switching device is required, and such a switch is damaged or has a shortened life span with repeated use. SUMMARY

[0005] An object of the present invention is to provide a motor driving device and an air conditioner including the same, which limit switching of a winding switching device in a case where a possibility of deterioration of the winding switching device occurs, thereby prolonging the life span of the winding switching device and preventing a failure of the motor driving device.

[0006] An object of the present invention is also to provide a motor driving device and an air conditioner including the same, which can determine whether a winding switching device that switches a connection of a motor has an abnormality.

[0007] An object of the present invention is also to provide a motor driving device and an air conditioner including the same, which can determine whether a winding switching device that switches a connection of a motor has an abnormality based on a winding resistance in a first connection and a winding resistance in a second connection based on an operation of the winding switching device.

[0008] An object of the present invention is also to provide a motor driving device and an air conditioner including the same, which can improve power conversion efficiency or motor driving efficiency in a case where the winding switching device normally operates.

[0009] An object of the present invention is also to provide a motor driving device and an air conditioner including the same, which can make the winding switching device operate in any one of a first connection and a second connection in a case where the winding switching device has an abnormality.

[0010] The present application also aims to provide a motor driving device capable of determining whether a motor has failed and an air conditioner including the same.

[0011] The present application is characterized by limiting switching of a switching device in a situation where switching of a winding is required to be repeated.

[0012] Specifically, the motor driving device and the air conditioner including the same according to the present application are characterized by including: an inverter provided with a plurality of switching devices, which outputs an alternating-current power to a motor based on switching operations; a switching device configured between the inverter and the motor, which converts a winding of the motor to a first connection method or a second connection method; and a control unit, which controls the inverter and the switching device; and if a number of low-speed abnormal operations of the motor, in which the motor is operated at an operating frequency below a limit frequency within a predetermined time, exceeds a first threshold value in a state of the second connection method, the control unit limits conversion of the connection method of the winding of the motor.

[0013] The control unit can allow conversion of the connection method of the winding of the motor after a first time elapses in a connection method state change limit state of the winding of the motor.

[0014] The control unit can initialize a cumulative value for the number of low-speed abnormal operations after a first time elapses in a connection method state change limit state of the winding of the motor.

[0015] In addition, the present application can be further characterized by further including an output current detection unit that detects an output current output from the inverter, and an output current value in a state of the first connection method can be less than an output current value in a state of the second connection method at the limit frequency.

[0016] The output current value in the state of the first connection method can be less than 1 / √3 times a maximum value of the output current in the state of the second connection method at the limit frequency.

[0017] The control unit can control the winding of the motor to be in a state of the first connection method if the operating frequency of the motor is below a first operating frequency.

[0018] The control unit can control the winding of the motor to be in a state of the second connection method if the operating frequency of the motor exceeds the first operating frequency.

[0019] The control unit can control the motor to continuously operate without stopping during conversion of the winding of the motor from the first connection method to the second connection method.

[0020] If the number of low-speed abnormal operations of the motor operating at an operating frequency below the limit frequency within a prescribed time in the state of the second connection method is less than a first threshold value, the control section can switch the winding of the motor to the first connection method or maintain the second connection method according to the operating frequency of the motor.

[0021] If the number of low-speed abnormal operations of the motor operating at an operating frequency below the limit frequency within a prescribed time in the state of the second connection method is less than a first threshold value, the control section can switch the winding of the motor to the first connection method or maintain the second connection method according to the operating speed of the motor.

[0022] In a case where the operating speed of the motor is below a first speed, the control section controls so that the winding of the motor is in the state of the first connection method.

[0023] In a case where the operating speed of the motor exceeds the first speed, the control section controls so that the winding of the motor is maintained in the state of the second connection method.

[0024] Further, the present application can include an output current detection section that detects an output current output from the inverter, and according to the check mode of the switching device, if the winding of the motor is in the state of the first connection method according to the operation of the switching device in a first period, the control section controls so that an output current of a first level is output from the inverter, and if the winding of the motor is in the state of the second connection method according to the operation of the switching device in a second period after the first period, the control section controls so that the output current of the first level is output from the inverter.

[0025] The control section can determine whether or not the operation of the switching device is abnormal based on the first winding resistance of the motor in the first connection method and the second winding resistance of the motor in the second connection method.

[0026] The control section can calculate the first winding resistance and the second winding resistance for each phase, and in a case where the range of the first winding resistance for each phase deviates from a first range and the range of the second winding resistance for each phase deviates from a second range, the control section determines that the motor is faulty, and in a case where the range of the first winding resistance for each phase is within the first range and the range of the second winding resistance for each phase is within the second range, the control section determines that the switching device is normal, and controls the switching device to switch the winding of the motor from the first connection method to the second connection method according to the operating frequency of the motor.

[0027] In another aspect, another embodiment of the present application is characterized by an inverter provided with a plurality of switching devices, an inverter control section configured to output an alternating-current power to a motor based on switching operations of the switching devices, a switching device configured to convert a winding of the motor to a first connection method or a second connection method, and a control section configured to control the inverter and the switching device, wherein if a number of low-speed abnormal operations of the motor in which the motor is operated at an operating frequency below a limit frequency within a predetermined time exceeds a first threshold value in a state in which the winding of the motor is in the second connection method, the control section maintains the second connection method. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a diagram showing a configuration of an air conditioner according to an embodiment of the present application.

[0029] Figure 2 is a diagram showing a configuration of an air conditioner according to an embodiment of the present application. Figure 1

[0030] Figure 3 is a diagram showing a configuration of an air conditioner according to an embodiment of the present application. Figure 1

[0031] Figure 4 is a diagram showing a configuration of an air conditioner according to an embodiment of the present application.

[0032] Figure 5 is a diagram showing a configuration of an air conditioner according to an embodiment of the present application. Figure 4

[0033] Figure 6 is a diagram showing a configuration of an air conditioner according to an embodiment of the present application. Figure 5

[0034] is a diagram showing a configuration of an air conditioner according to an embodiment of the present application. Figure 7 Figure 4 is a diagram showing a configuration of an air conditioner according to an embodiment of the present application.

[0035] Figure 8A Figure 8B is a diagram showing a configuration of an air conditioner according to an embodiment of the present application. Figure 7

[0036] Figure 9A is a diagram showing a configuration of an air conditioner according to an embodiment of the present application.

[0037] Figure 9B is a diagram showing a configuration of an air conditioner according to an embodiment of the present application.

[0038] Figures 10A to 14C is a diagram showing a configuration of an air conditioner according to an embodiment of the present application. Figure 9A Figure 9B

[0039] ​​​​​​​​Figure 15 is a flowchart showing a method of operating the motor driving device according to another embodiment of the present application.

[0040] Figures 16A to 16C is a diagram for explaining the operation of Figure 15 .

[0041] Figure 17 is a flowchart showing a method of operating the motor driving device according to another embodiment of the present application. DETAILED DESCRIPTION

[0042] Hereinafter, the present application will be described in greater detail with reference to the accompanying drawings.

[0043] The suffixes "module" and "part" used in the following description with respect to structural elements are merely given to facilitate writing of the specification, and do not have any particular meaning or role. Thus, the "module" and "part" can be used interchangeably.

[0044] Figure 1 is a diagram showing the configuration of an air conditioner according to an embodiment of the present application.

[0045] As shown in Figure 1 , the air conditioner according to the present application is a large-sized air conditioner 100, which can include a plurality of indoor units 31 to 35, a plurality of outdoor units 21 and 22 connected to the plurality of indoor units, a plurality of remote controllers 41 to 45 connected to each of the plurality of indoor units, and a remote controller 10 controlling the plurality of indoor units and the outdoor units.

[0046] The remote controller 10 is connected to the plurality of indoor units 31 to 36 and the plurality of outdoor units 21 and 22 and monitors and controls the operation thereof. At this time, the remote controller 10 can be connected to the plurality of indoor units and perform operation setting, lock setting, schedule control, group control, etc. with respect to the indoor units.

[0047] The air conditioner 100 can be any one of a floor standing type air conditioner, a wall mounted type air conditioner, and a ceiling mounted type air conditioner, but hereinafter, the ceiling mounted type air conditioner will be described as an example for convenience of description.

[0048] In addition, the air conditioner can further include at least one of a ventilation device, an air purifier, a humidifier, and a heater, and can operate in linkage with the operation of the indoor units and the outdoor units.

[0049] The outdoor units 21, 22 include a compressor (not shown) that receives and compresses refrigerant, an outdoor heat exchanger (not shown) that exchanges heat between refrigerant and outdoor air, a receiver (not shown) that extracts gaseous refrigerant from supplied refrigerant and supplies it to the compressor, and a four-way valve (not shown) that selects a flow path of refrigerant according to heating operation. In addition, a plurality of sensors, valves, and an oil collector, etc. are included, but the explanation of these configurations is omitted here.

[0050] The outdoor units 21, 22 compress refrigerant or exchange heat according to settings by operating the compressor and the outdoor heat exchanger included therein, and then supply the refrigerant to the indoor units 31 to 35. The outdoor units 21, 22 are driven according to the demand of the remote controller 10 or the indoor units 31 to 35, and the number of operation of the outdoor units and the number of operation of the compressors provided in the outdoor units change according to the refrigeration / heating capacity corresponding to the driven indoor units.

[0051] At this time, the outdoor units 21, 22 are basically explained in the case where a plurality of outdoor units supply refrigerant to the respective indoor units connected thereto, but a plurality of outdoor units can be connected to each other and supply refrigerant to a plurality of indoor units according to the connection structure of the outdoor units and the indoor units.

[0052] The indoor units 31 to 35 receive refrigerant by being connected to any one of the plurality of outdoor units 21, 22, and discharge cold air or hot air to the indoor. The indoor units 31 to 35 include an indoor heat exchanger (not shown), an indoor unit fan (not shown), an expansion valve (not shown) that expands the supplied refrigerant, and a plurality of sensors (not shown).

[0053] At this time, the outdoor units 21, 22 and the indoor units 31 to 35 are connected by a communication line and transmit and receive data to each other, and the outdoor units and the indoor units are connected to the remote controller 10 by a separate communication line and operate according to the control of the remote controller 10.

[0054] The remote controllers 41 to 45 are connected to the indoor units, respectively, input control instructions of a user to the indoor units, and receive and display status information of the indoor units. At this time, the remote controllers communicate in a wired or wireless manner according to the connection form with the indoor units, and one remote controller can be connected to a plurality of indoor units and the settings of the plurality of indoor units can be changed by the input of one remote controller according to the situation.

[0055] In addition, the remote controllers 41 to 45 can be provided with a temperature sensing sensor inside.

[0056] Figure 2 is Figure 1 a schematic view of the outdoor unit and the indoor unit.

[0057] Referring to the drawings, an air conditioner 100 is roughly divided into an indoor unit 31 and an outdoor unit 21.

[0058] The outdoor unit 21 includes a compressor 102 that functions to compress a refrigerant, a compressor motor 102b that drives the compressor, an outdoor heat exchanger 104 that functions to radiate the compressed refrigerant, an outdoor blower fan 105 that is disposed at one side of the outdoor heat exchanger 104 and is composed of an outdoor fan 105a that promotes the radiation of the refrigerant and a motor 105b that rotates the outdoor fan 105a, an expansion mechanism 106 that expands the condensed refrigerant, a refrigerant / heating switching valve 110 that switches a flow path of the compressed refrigerant, and a receiver 103 that temporarily stores the vaporized refrigerant and supplies the refrigerant having a prescribed pressure to the compressor after removing moisture and foreign matter, etc.

[0059] The indoor unit 31 includes an indoor heat exchanger 108 that is disposed in an indoor room to perform a refrigeration / heating function, and an indoor blower fan 109 that is disposed at one side of the indoor heat exchanger 108 and is composed of an indoor fan 109a that promotes the radiation of the refrigerant and a motor 109b that rotates the indoor fan 109a, etc.

[0060] The indoor heat exchanger 108 can be provided with at least one. The compressor 102 can use at least one of a variable frequency compressor and a constant speed compressor.

[0061] In addition, the air conditioner 100 can be a refrigerator that cools an indoor room, or can be a heat pump that cools or heats an indoor room.

[0062] On the other hand, in Figure 2 , the indoor unit 31 and the outdoor unit 21 are shown as each one, but the driving device of the air conditioner according to the embodiment of the present application is not limited thereto, and can be a multi-split air conditioner including a plurality of indoor units and outdoor units, and of course, can be applied to an air conditioner including one indoor unit and a plurality of outdoor units, etc.

[0063] Figure 1 The compressor 102 in the outdoor unit 21 of the air conditioner 100 can be driven by a motor driving device 220 that drives a compressor motor 230 to drive the compressor.

[0064] Figure 3 is Figure 1 a brief internal block diagram of the air conditioner 100.

[0065] Referring to the drawings, Figure 3 The air conditioner 100 of the air conditioner 100 includes a compressor 102, an outdoor fan 105a, an indoor fan 109a, a control portion 170, an outlet temperature sensing portion 118, an outdoor temperature sensing portion 138, an indoor temperature sensing portion 158, and a memory 140.

[0066] In addition, the air conditioner 100 can further include a motor driving device 220, an outdoor fan driving part 200, an indoor fan driving part 300, a switching valve 110, an expansion valve 106, a display part 130, and an input part 120.

[0067] For the description of the compressor 102, the outdoor fan 105a, and the indoor fan 109a, refer to Figure 2 .

[0068] The input part 120 includes a plurality of operation buttons, and transmits a signal about an input target temperature of the air conditioner 100 to the control part 170.

[0069] The display part 130 can display an operation state of the air conditioner 100.

[0070] The memory 140 can store data required for the operation of the air conditioner 100.

[0071] The discharge temperature sensing part 118 can sense a refrigerant discharge temperature Tc discharged from the compressor 102, and transmit a sensed signal about the refrigerant discharge temperature Tc to the control part 170.

[0072] The outdoor temperature sensing part 138 can sense an outdoor temperature To, i.e., a temperature of the periphery of the outdoor unit 21 of the air conditioner 100, and transmit a sensed signal about the outdoor temperature To to the control part 170.

[0073] The indoor temperature sensing part 158 can sense an indoor temperature Ti, i.e., a temperature of the periphery of the indoor unit 31 of the air conditioner 100, and transmit a sensed signal about the indoor temperature Ti to the control part 170.

[0074] The control part 170 can control the operation of the air conditioner 100 based on at least one of the sensed refrigerant discharge temperature Tc, the sensed outdoor temperature To, the sensed indoor temperature Ti, and the input target temperature. For example, a final target superheat degree can be calculated, and the operation of the air conditioner 100 can be controlled.

[0075] On the other hand, as shown in the drawing, the control part 170 can control the motor driving device 220, the outdoor fan driving part 200, and the indoor fan driving part 300, respectively, in order to control the operation of the compressor 102, the indoor fan 109a, and the outdoor fan 105a.

[0076] For example, the control part 170 can output a corresponding speed command value signal to the motor driving device 220, the outdoor fan driving part 200, or the indoor fan driving part 300, respectively, based on the target temperature.

[0077] After that, the compressor motor (not shown), the motor 230, and the indoor fan motor 109b can operate at the target rotational speeds based on the respective speed command value signals, respectively.

[0078] On the other hand, the control portion 170 can control the entire operation of the air conditioner 100 in addition to performing control over the motor drive device 220, the outdoor fan drive portion 200, or the indoor fan drive portion 300.

[0079] For example, the control portion 170 can control the operation of the cooling / heating switching valve 110 or the four-way valve.

[0080] In addition, the control portion 170 can control the operation of the expansion mechanism or the expansion valve 106.

[0081] Figure 4 An example of an internal block diagram of the motor drive device of the embodiment of the present application is shown, Figure 5 Figure 4 An example of an internal circuit diagram of the motor drive device of the embodiment of the present application is shown.

[0082] Referring to the drawings, the motor drive device 220 of the embodiment of the present application is used to drive a motor in a sensorless manner, and can also be named as a power conversion device.

[0083] The motor drive device 220 of the embodiment of the present application can include a converter 410, an inverter 420, an inverter control portion 430, a switching device 450, a DC terminal voltage detection portion B, a DC terminal capacitor C, an output current detection portion E, and an output voltage detection portion F. In addition, the motor drive device 220 can also include an input current detection portion A, and the like.

[0084] The input current detection portion A can detect an input current is input from the commercial AC power source 405. For this purpose, as the input current detection portion A, a CT (current transformer), a shunt resistor, or the like can be used. The detected input current is can be input to the inverter control portion 430 as a discrete signal in a pulse form.

[0085] The converter 410 converts the commercial AC power source 405 via a reactor L into a DC power source and outputs. Although the commercial AC power source 405 is shown as a three-phase AC power source in the drawing, it can also be a single-phase AC power source. The internal structure of the converter 410 can also vary depending on the type of the commercial AC power source 405.

[0086] On the other hand, the converter 410 can be configured by a diode or the like without a switching device, and thus the rectification operation can also be performed without an additional switching operation. ​

[0087] For example, in the case of a three-phase AC power source, the converter 410 can be provided with six diodes in a bridge form, and in the case of a single-phase AC power source, the converter 410 can be provided with four diodes in a bridge form.

[0088] On the other hand, in the case of a three-phase AC power source, the converter 410 can be provided with six switching devices and six diodes, and in the case of a single-phase AC power source, the converter 410 can be a half-bridge type converter provided with two switching devices and four diodes.

[0089] In the case where the converter 410 is provided with a switching device, a boost operation, power factor improvement, and DC power conversion can be performed by the switching operation of the switching device.

[0090] The DC terminal capacitor C is disposed at the DC terminal and stores the power source output from the converter 410. In the drawing, one element is shown as the DC terminal capacitor C, but a plurality of elements can be provided to ensure element stability.

[0091] On the other hand, in the drawing, an example is shown in which the DC terminal capacitor C is connected to the output terminal of the converter 410, but it is not limited thereto, and a DC power source can be directly input.

[0092] For example, a DC power source from a solar cell can be directly input to the DC terminal capacitor C, or a DC / DC conversion can be performed and then input. Hereinafter, a description will be made mainly with respect to the parts shown in the drawing.

[0093] On the other hand, since the DC terminal capacitor C stores a DC power source across both terminals, it can also be named as a DC terminal or a DC link terminal.

[0094] The DC terminal voltage detection section B can detect a DC terminal voltage Vdc across both terminals of the DC terminal capacitor C. To this end, the DC terminal voltage detection section B can include a resistance element, an amplifier, or the like. The detected DC terminal voltage Vdc can be input to the inverter control section 430 as a discrete signal in a pulse form.

[0095] The inverter 420 can be provided with a plurality of inverter switching devices Sa to Sc, S'a to S'c, and a DC power source Vdc at the DC terminal can be converted to a three-phase AC power source va, vb, vc and output to the three-phase synchronous motor 230 by the on / off operation of the switching devices.

[0096] In the inverter 420, the upper arm switching devices Sa, Sb, Sc and the lower arm switching devices S'a, S'b, S'c connected in series with each other are paired, and three pairs of the upper arm switching devices and the lower arm switching devices Sa & S'a, Sb & S'b, Sc & S'c are connected in parallel with each other. A diode connected in anti-parallel is connected to each of the switching devices Sa, S'a, Sb, S'b, Sc, S'c.

[0097] The switching devices in the inverter 420 perform on / off operations of the respective switching devices based on an inverter switching control signal Sic from the inverter control section 430. Thereby, a three-phase alternating-current power source having a prescribed frequency is output to the three-phase synchronous motor 230.

[0098] The inverter control section 430 can control the switching operations of the inverter 420 based on a sensorless method. To this end, the inverter control section 430 can receive an output current io detected by the output current detection section E.

[0099] To control the switching operations of the inverter 420, the inverter control section 430 outputs an inverter switching control signal Sic to the inverter 420. The inverter switching control signal Sic is a pulse width modulation (PWM) type switching control signal, which is generated and output based on the output current io detected by the output current detection section E. The detailed operations of the output of the inverter switching control signal Sic in the inverter control section 430 will be described later with reference to FIG. 6. Figure 6 The detailed operations of the output of the inverter switching control signal Sic in the inverter control section 430 will be described later with reference to FIG. 6.

[0100] The output current detection section E detects an output current io flowing between the inverter 420 and the three-phase motor 230. That is, the output current flowing in the motor 230 is detected. The output current detection section E can detect the output current ia, ib, ic of each phase, or can detect the output current of two phases using three-phase balance.

[0101] The output current detection section E can be located between the inverter 420 and the motor 230, and a CT (current transformer), a shunt resistor, or the like can be used to detect the current.

[0102] In the case of using a shunt resistor, three shunt resistors can be located between the inverter 420 and the synchronous motor 230, or one end of each of the three shunt resistors can be connected to the three lower arm switching devices S'a, S'b, S'c of the inverter 420.

[0103] On the other hand, two shunt resistors can be used using three-phase balance. On the other hand, in the case of using one shunt resistor, the shunt resistor can be disposed between the above-described capacitor C and the inverter 420.

[0104] The detected output current io is a discrete signal in a pulse form, which can be applied to the inverter control section 430, and an inverter switching control signal Sic is generated based on the detected output current io. Hereinafter, the detected output current io can also be described in parallel as output currents ia, ib, ic of three phases.

[0105] The output voltage detection section F can detect an output voltage vo output from the inverter 420. Specifically, output voltages vo of respective phases output from the inverter 420 can be detected. To this end, the output voltage detection section F can include a resistance element, an amplifier, or the like. The detected output voltage vo can be input to the inverter control section 430 as a discrete signal in a pulse form.

[0106] On the other hand, the three-phase motor 230 is provided with a stator and a rotor, and the rotor is rotated by applying an alternating current power of a predetermined frequency to coils of the stator of each phase (a phase, a b phase, and a c phase).

[0107] For example, such a motor 230 can include a surface-mounted permanent-magnet synchronous motor (SMPMSM), an interior permanent-magnet synchronous motor (IPMSM), and a synchronous reluctance motor (Synrm), or the like. Among them, the SMPMSM and the IPMSM are synchronous motors (PMSM) using permanent magnets, and the Synrm is characterized by not having a permanent magnet.

[0108] On the other hand, the switching device 450 can be disposed between the inverter 420 and the motor 230, and can convert the winding of the motor 230 to a first connection method or a second connection method.

[0109] Here, the first connection method can be a Y connection method, and the second connection method can be a delta connection method.

[0110] To this end, the switching device 450 can be provided with three relay elements SW1 to SW3 connected between the three-phase output of the inverter 420 and the three-phase coils CA, Cb, and CC of the motor 230, respectively.

[0111] That is, the switching device 450 can be provided with the first relay element SW1 to the third relay element SW3 electrically connected to each phase.

[0112] The switching device 450 can act to make the motor 230 into the first connection method when the motor 230 is below the first speed or the first operating frequency, and can act to make the motor 230 into the second connection method when the motor 230 exceeds the first speed or the first operating frequency. Thus, the power conversion efficiency or the motor drive efficiency can be improved.

[0113] In particular, the power conversion efficiency or the motor drive efficiency in the case of low speed below the first speed or the first operating frequency can be improved.

[0114] On the other hand, the motor drive device 220 of the embodiment of the present application includes: an inverter 420 provided with a plurality of switching devices Sa to Sc, S'a to S'c, which outputs an alternating-current power to the motor 230 based on switching operation; a switching device 450 disposed between the inverter 420 and the motor 230, which converts the winding of the motor 230 into the first connection method or the second connection method; an output current detection section E, which detects an output current io output from the inverter 420; and a control section 170 or an inverter control section 430, which controls the inverter 420 and the switching device 450; according to the check mode of the switching device 450, in a first period Pn1, the output current io of a first level Lvn1 is output from the inverter 420 in a state where the winding of the motor 230 is in the first connection method according to the operation of the switching device 450, and in a second period Pn2 after the first period Pn1, the output current io of the first level Lvn1 is output from the inverter 420 in a state where the winding of the motor 230 is in the second connection method according to the operation of the switching device 450. Thus, it is possible to determine whether the switching device 450, which converts the connection method of the motor 230, has an abnormality. For this, the following will be described in detail with reference to Figure 7

[0115] Figure 6 Figure 5 is an internal block diagram of the inverter control section.

[0116] Referring to Figure 6 , the inverter control section 430 can include a shaft conversion section 310, a speed operation section 320, a current command generation section 330, a voltage command generation section 340, a shaft conversion section 350, and a switching control signal output section 360.

[0117] The shaft conversion section 310 receives the three-phase output currents ia, ib, ic detected by the output current detection section E and converts them into two-phase currents iα, iβ of a stationary coordinate system.

[0118] On the other hand, the shaft conversion section 310 can convert the two-phase currents iα, iβ of the stationary coordinate system into two-phase currents id, iq of a rotating coordinate system.

[0119] ​​The speed calculation unit 320 can output the calculated position and the calculated speed

[0120] On the other hand, the current command generation unit 330 generates a current command value i* q based on the calculated speed and a speed command value ω* r . For example, the current command generation unit 330 performs PI control by a PI controller 335 based on the difference between the calculated speed and the speed command value ω* r , and generates a current command value i* q . In the drawing, the q-axis current command value i* q is shown as the current command value, but the d-axis current command value i* d may be generated together, differently from the drawing. On the other hand, the value of the d-axis current command value i* d may be set to 0.

[0121] On the other hand, the current command generation unit 330 can also provide a limiter (not shown) that limits the level of the current command value i* q so that the current command value i* q does not exceed the allowable range.

[0122] Next, the voltage command generation unit 340 generates a d-axis voltage command value v* d and a q-axis voltage command value v* q based on the d-axis current i d , the q-axis current i q , which are axis-converted into the two-phase rotating coordinate system at the axis conversion unit, and the current command values i* d , i* q at the current command generation unit 330 or the like. For example, the voltage command generation unit 340 generates the q-axis voltage command value v* q by performing PI control by a PI controller 344 based on the difference between the q-axis current i q and the q-axis current command value i* q . In addition, the voltage command generation unit 340 can generate the d-axis voltage command value v* d by performing PI control by a PI controller 348 based on the difference between the d-axis current i d and the d-axis current command value i* d . On the other hand, the voltage command generation unit 340 can also provide a limiter (not shown) that limits the level of the d-axis voltage command value v* d and the q-axis voltage command value v* q so that the d-axis voltage command value v*d and the q-axis voltage command value v*q does not exceed the allowable range.

[0123] On the other hand, the generated d-axis voltage command value v* d and q-axis voltage command value v* q is input to the axis conversion section 350.

[0124] The axis conversion section 350 receives the position and d-axis voltage command value v*d, q-axis voltage command value v* q and performs axis conversion.

[0125] First, the axis conversion section 350 performs conversion from the two-phase rotating coordinate system to the two-phase stationary coordinate system. At this time, the position

[0126] Also, the axis conversion section 350 performs conversion from the two-phase stationary coordinate system to the three-phase stationary coordinate system. Through this conversion, the axis conversion section 350 outputs three-phase output voltage command values v*a, v*b, v*c.

[0127] The switch control signal output section 360 generates and outputs an inverter switch control signal Sic according to a pulse width modulation (PWM) method, based on the three-phase output voltage command values v*a, v*b, v*c.

[0128] The output inverter switch control signal Sic can be converted to a gate drive signal at a gate drive section (not shown) and input to the gate of each switching device within the inverter 420. Thereby, each switching device Sa, S'a, Sb, S'b, Sc, S'c within the inverter 420 performs switching operation.

[0129] On the other hand, as described above, in order to perform vector control of driving the motor 230 by the inverter 420 control, the motor drive device 220 is required to sense the output current io, particularly the phase current, flowing in the motor.

[0130] The inverter control section 430 can control the motor 230 to the desired speed and torque by the current command generation section 330 and the voltage command generation section 340 using the sensed phase current.

[0131] Figure 7 is a diagram referred to at the time of operation of the switching device described in Figure 4

[0132] With reference to the accompanying drawings, Figure 7 ​(a) shows a case where the motor 230 operates in Y connection as the first connection method according to the operation of the switching device 450, Figure 7 (b) shows a case where the motor 230 operates in Δ connection as the second connection method according to the operation of the switching device 450.

[0133] The switching device 450 is provided with a first relay element SW1 to a third relay element SW3 that are electrically connected to each phase output of the inverter 420.

[0134] A first end naa of the first relay element SW1, a first end nba of the second relay element SW2, and a first end nca of the third relay element SW3 are connected in parallel, one end nA of the first winding CA of the motor 230 is connected to a second end nab of the first relay element SW1, one end nB of the second winding CB of the motor 230 is connected to a second end nbb of the second relay element SW2, one end nC of the third winding CC of the motor 230 is connected to a second end ncb of the third relay element SW3, the other end nA of the first winding CA of the motor 230 is connected to a common end n3 of the third relay element SW3, the other end nB of the second winding CB of the motor 230 is connected to the common end n1 of the first relay element SW1, and the other end nC of the third winding CC of the motor 230 is connected to the common end n2 of the second relay element SW2.

[0135] On the other hand, the second end nab of the first relay element SW1 is connected to a u-phase output terminal ru of the inverter 420, the second end nbb of the second relay element SW2 is connected to a v-phase output terminal rv of the inverter 420, and the second end ncb of the third relay element SW3 is connected to a w-phase output terminal rw of the inverter 420.

[0136] As shown in (a) of FIG. 10, Figure 7 The control section 170 or the inverter control section 430 can control the common ends n1, n2, n3 of the first relay element SW1 to the third relay element SW3 to be electrically connected to the first ends naa, nba, nca of the first relay element SW1 to the third relay element SW3, respectively, for the first connection method.

[0137] Accordingly, the output currents of the u-phase, the v-phase, and the w-phase of the inverter 420 flow in the a-phase coil CA, the b-phase coil CB, and the c-phase coil CC in the motor 230 as Y connection, respectively.

[0138] As shown in (b) of FIG. 10, Figure 7As shown in (b), the control unit 170 or the inverter control unit 430 can control the common terminals n1, n2, and n3 of the first relay element SW1 to the third relay element SW3 to be electrically connected to the second terminals nab, nbb, and ncb of the first relay element SW1 to the third relay element SW3 respectively for the second connection method.

[0139] Therefore, the output currents of the u-phase, v-phase, and w-phase of the inverter 420 flow in the b-phase coil CB, c-phase coil CC, and a-phase coil CA of the motor 230, which is connected in a delta configuration.

[0140] Ultimately, the motor 230 can be controlled to operate in either the first or second connection via the switching device 450, thereby improving the power conversion efficiency or the driving efficiency of the motor 230.

[0141] Figure 8A and Figure 8B It means Figure 7 The timing diagram of the winding switching action of the switching device.

[0142] first, Figure 8A This is a timing diagram illustrating an example of the winding switching operation of a switching device.

[0143] Referring to the attached diagram, when the operating frequency of motor 230 is below f1, such as Figure 7 As shown in (a), the switching device 450 can be operated to make the motor 230 Y-connected.

[0144] The accompanying drawing shows that during the P1x period up to time Txa, the switching device 450 operates to put the motor 230 into a Y-connected state.

[0145] Then, during the period from time Txa to time Txb up to time Px, motor 230 can be stopped.

[0146] Then, during the P2x period after time Txb, as... Figure 7 As shown in (b), the switching device 450 can be operated to put the motor 230 into a Δ connection state.

[0147] For example, if the operating frequency of motor 230 exceeds f1, the switching device 450 can operate to put motor 230 into a Δ connection state. In order to switch from Y connection to Δ connection, motor 230 can be stopped during Px.

[0148] then, Figure 8B This is a timing diagram representing another example of the winding switching operation of a switching device.

[0149] Referring to the attached diagram, when the operating frequency of motor 230 is below f1, such as Figure 7As shown in (b) of FIG. 9, the switching device 450 can act so that the motor 230 becomes in the Y-connection state.

[0150] In the drawing, it is shown that during P1 until time Ta, the switching device 450 acts so that the motor 230 becomes in the Y-connection state.

[0151] Next, during P2 between time Ta and time Tb, the control section 170 or the inverter control section 430 can control so that the winding of the motor 230 is switched from the first connection to the second connection.

[0152] In particular, the control section 170 or the inverter control section 430 can control during P2 so that the motor 230 does not stop, but the operating frequency of the motor 230 is temporarily lowered from the first frequency fl to the second frequency f2.

[0153] Next, during P3 after time Tb, as shown in (b) of FIG. 10, the motor 230 can act so that it becomes in the Δ-connection state. Figure 7

[0154] For example, in the case where the operating frequency of the motor 230 exceeds fl, the control section 170 or the inverter control section 430 can control so that the switching device 450 acts so that the motor 230 becomes in the Δ-connection state.

[0155] In particular, during P3, the control section 170 or the inverter control section 430 can control so that the operating frequency of the motor 230 temporarily lowered to the second frequency f2 is raised again.

[0156] The control section 170 or the inverter control section 430 can control so that the motor 230 continues to act without stopping during the period in which the switching device 450 switches the winding of the motor 230 from the first connection to the second connection. As described above, since the motor 230 does not stop when the switching device 450 performs the switching action, the operating efficiency of the motor 230 can be improved.

[0157] On the other hand, it is preferable that Figure 8B the P2 period of (a) be less than Figure 8A the Px period of (b). Thereby, the winding of the motor 230 can be switched from the first connection to the second connection while temporarily lowering the speed of the motor 230.

[0158] Figure 9A is a flowchart showing an operating method of a motor drive device according to an embodiment of the present application.

[0159] Referring to the drawing, the control section 170 or the inverter control section 430 determines whether it is in the switching device check mode in the motor drive device 220 (S910).

[0160] ​For example, the control section 170 or the inverter control section 430 can be controlled to execute the switching device check mode before the motor 230 is driven.

[0161] As another example, if the change in the operating frequency is equal to or greater than a prescribed value in the driving of the motor 230, the control section 170 or the inverter control section 430 can be controlled to execute the switching device check mode.

[0162] In the case of the switching device check mode, the control section 170 or the inverter control section 430 is controlled to cause the inverter 420 to output an output current of a first level in a state in which the winding of the motor 230 is in the first connection method according to the operation of the switching device 450 for a first period (S920).

[0163] Next, in the case of the switching device check mode, the control section 170 or the inverter control section 430 is controlled to cause the inverter 420 to output an output current of the first level, which is the same as in the state of the first connection method, in a state in which the winding of the motor 230 is in the second connection method according to the operation of the switching device 450 for a second period after the first period (S930).

[0164] Next, the control section 170 or the inverter control section 430 determines whether or not the operation of the switching device 450 is abnormal based on the winding resistance of the motor 230 in the first connection method and the winding resistance of the motor 230 in the second connection method (S940).

[0165] For example, the control section 170 or the inverter control section 430 can calculate the first winding resistance of the motor 230 based on a first output voltage Lvn3 detected based on the output current io of the first level Lvn1 output for the first period Pn1, calculate the second winding resistance of the motor 230 based on a second output voltage Lvn4 detected based on the output current io of the first level Lvn1 output for the second period Pn2, and determine whether or not the operation of the switching device 450 is abnormal based on the first winding resistance and the second winding resistance. Thus, it is possible to easily determine whether or not the switching device 450 that switches the connection method of the motor 230 is abnormal.

[0166] Specifically, the control section 170 or the inverter control section 430 can calculate the ratio of the first winding resistance and the second winding resistance, and determine whether or not the operation of the switching device 450 is abnormal based on the calculated ratio. Thus, it is possible to easily determine whether or not the switching device 450 that switches the connection method of the motor 230 is abnormal.

[0167] On the other hand, the control section 170 or the inverter control section 430 can calculate the ratio of the first winding resistance and the second winding resistance for each phase, and in a case where the ratio of all the phases in the calculated ratio is within a prescribed range, determine that the switching device 450 is normal, and control so that the switching device 450 switches the winding of the motor 230 from the first connection to the second connection in accordance with the operating frequency of the motor 230. Thus, it is possible to improve the power conversion efficiency or the driving efficiency of the motor 230 in a case where the switching device 450 is normally operating.

[0168] Figure 9B is a flowchart showing an operating method of a motor driving device according to another embodiment of the present application.

[0169] Referring to the drawings, Figure 9B the operating method of Figure 9A is similar to the operating method of

[0170] Here, the step 910 (S910), the step 920 (S920), the step 930 (S930), and the step 940 (S940) refer to the description of Figure 9A

[0171] In the step 920 (S920), in a case of the switching device check mode, the control section 170 or the inverter control section 430 controls so that, in the first period, the winding of the motor 230 is in a state where the winding is in the first connection in accordance with the operation of the switching device 450, the inverter 420 outputs the output current of the first level.

[0172] Next, the control section 170 or the inverter control section 430 controls so that, in the first period, the winding of the motor 230 is in a state where the winding is in the first connection in accordance with the operation of the switching device 450, the inverter 420 outputs the output current of the second level different from the first level after outputting the output current of the first level (S922).

[0173] For example, the second level can be a level higher than the first level.

[0174] Next, in a case of the switching device check mode, the control section 170 or the inverter control section 430 controls so that, in the second period, the winding of the motor 230 is in a state where the winding is in the second connection in accordance with the operation of the switching device 450, the inverter 420 outputs the output current of the first level (S930).

[0175] ​Next, the control section 170 or the inverter control section 430 controls so that, in the second period, the winding of the motor 230 is in a state of the second connection method according to the operation of the switching device 450, and the inverter 420 outputs an output current of a second level different from the first level after outputting an output current of the first level (S932).

[0176] The first level and the second level in the state of the second connection method can be the same levels as the first level and the second level in the state of the first connection method, respectively.

[0177] Next, the control section 170 or the inverter control section 430 determines whether or not the operation of the switching device 450 is abnormal based on the winding resistance of the motor 230 in the first connection method and the winding resistance of the motor 230 in the second connection method (S940).

[0178] For example, the control section 170 or the inverter control section 430 calculates the first winding resistance of the motor 230 based on the output voltage Lvm3 detected based on the output current of the first level Lvm1 in the first period Pm1 and the output voltage Lvm4 detected based on the output current of the second level Lvm2, and calculates the second winding resistance of the motor 230 based on the output voltage Lvm5 detected based on the output current of the first level Lvm1 in the second period Pm2 and the output voltage Lvm6 detected based on the output current of the second level Lvm2, and determines whether or not the operation of the switching device 450 is abnormal based on the first winding resistance and the second winding resistance. Thus, it is possible to easily determine whether or not the switching device 450 that switches the connection method of the motor 230 is abnormal.

[0179] Specifically, the control section 170 or the inverter control section 430 can calculate the ratio of the first winding resistance and the second winding resistance, and determine whether or not the operation of the switching device 450 is abnormal based on the calculated ratio. Thus, it is possible to easily determine whether or not the switching device 450 that switches the connection method of the motor 230 is abnormal.

[0180] On the other hand, the control section 170 or the inverter control section 430 can control so as to calculate the ratio of the first winding resistance and the second winding resistance for each phase, determine that the switching device 450 is normal in a case where the ratio of all the phases in the calculated ratio is within a prescribed range, and switch the winding of the motor 230 from the first connection method to the second connection method according to the operation frequency of the motor 230. Thus, it is possible to improve the power conversion efficiency or the driving efficiency of the motor 230 in a case where the switching device 450 operates normally.

[0181] Figures 10A to 14C is a diagram referred to when explaining Figure 9A or Figure 9B the operation method.

[0182] First, Figure 10A is a diagram referred to when explaining Figure 9A the operation method.

[0183] Referring to the drawings, Figure 10A (a) of FIG. 10 shows the output current ina output from the inverter 420, and particularly shows the phase current.

[0184] During Pn1, in a state where the motor 230 is in the first connection by the action of the switching device 450, the inverter control section 430 can be controlled to output the output current of the first level Lvn1 from the inverter 420.

[0185] Pns period after the Pn1 period is a conversion interval from the first connection to the second connection, and the inverter 420 can not output the current.

[0186] On the other hand, unlike the drawing, the output current lower than the first level Lvn1 can also be output during Pns. By outputting such an output current, as in the P2 period of FIG. 9, Figure 8B the speed of the motor 230 can temporarily decrease.

[0187] Next, during the Pn2 period after the Pns period, in a state where the motor 230 is in the second connection by the action of the switching device 450, the inverter control section 430 can be controlled to output the output current of the first level Lvn1 from the inverter 420.

[0188] Figure 10A (b) of FIG. 10 shows the switching voltage Sna corresponding to the output current ina output from the inverter 420 and the output voltage Snb as the effective voltage.

[0189] On the other hand, the output voltage Snb can correspond to the phase voltage.

[0190] Until the Tn1 time point as the end time point of the Pn1 period, the pulse width of the switching voltage Sna is kept constant after rising, and the output voltage is kept at the third level Lvn3 after rising.

[0191] During the Pns period after the Pn1 period, the output voltage becomes zero, and during the Pn2 period starting from the Tn2 time point after the Pns period, the pulse width of the switching voltage Sna is kept constant after rising, and the output voltage is kept at the fourth level Lvn4 lower than the third level Lvn3 after rising.

[0192] As in the P2 period of FIG. 9, Figure 10A(b), the control section 170 or the inverter control section 430 can calculate the first winding resistance in the first connection method and the second winding resistance in the second connection method based on the difference in the output voltage Snb between the first connection method and the second connection method.

[0193] On the other hand, since the output current output from the inverter 420 is the same, the first winding resistance whose level of the output voltage Snb is greater is greater than the second winding resistance if the operation of the switching device 450 is normal.

[0194] Based on this characteristic, the control section 170 or the inverter control section 430 can determine whether or not the operation of the switching device 450 is abnormal.

[0195] On the other hand, in the case where the output voltage Snb is the same in the first connection method and the second connection method, the control section 170 or the inverter control section 430 can control so that the first winding resistance in the first connection method and the second winding resistance in the second connection method are the same. Figure 10A One phase current ina is shown, but the control section 170 or the inverter control section 430 can also control so that the u-phase current, the v-phase current, and the w-phase current, which are the output terminals of the inverter 420, have waveforms in which the phase currents are sequentially the same, respectively, differently from this. Figure 10A

[0196] The control section 170 or the inverter control section 430 can calculate the first winding resistance in the first connection method and the second winding resistance in the second connection method using the relationship R = V / I.

[0197] At this time, in the case where the ratio of the first winding resistance in the first connection method and the second winding resistance in the second connection method is within a prescribed range, the control section 170 or the inverter control section 430 can determine that it is normal, and in the case where it is outside the prescribed range, it can determine that the switching device 450 is abnormal.

[0198] In addition, the control section 170 or the inverter control section 430 can determine whether or not the switching device 450 is abnormal or normal based on whether or not the first winding resistance in the first connection method is within the first range.

[0199] On the other hand, the control section 170 or the inverter control section 430 can also determine whether or not the switching device 450 is abnormal or normal based on whether or not the second winding resistance in the second connection method is within the second range.

[0200] Next, Figure 10B is a diagram referred to when explaining the operation method of Figure 9B .

[0201] Referring to the drawings, Figure 10B (a) shows the output current ima output from the inverter 420, and particularly shows the phase current.

[0202] ​During Pm1a in the Pm1 period, the inverter control section 430 can control to output an output current of a first level Lvm1 from the inverter 420 in a state where the motor 230 is in the first connection method according to the action of the switching device 450.

[0203] Next, during Pm1b in the Pm1 period, the inverter control section 430 can control to output an output current of a second level Lvm2 larger than the first level Lvm1 from the inverter 420 in a state where the motor 230 is in the first connection method according to the action of the switching device 450.

[0204] The Pms period after the Pm1 period is a conversion interval from the first connection method to the second connection method, and the inverter 420 can not output a current.

[0205] On the other hand, a current of a level lower than the output current of the first level Lvm1 can also be output during the Pms period, unlike the drawing. By outputting such an output current, as Figure 8B The speed of the motor 230 can temporarily decrease during P2.

[0206] Next, during Pm2a in the Pm2 period after the Pms period, the inverter control section 430 can control to output an output current of the first level Lvm1 from the inverter 420 in a state where the motor 230 is in the second connection method according to the action of the switching device 450.

[0207] Next, during Pm2b in the Pm2 period, the inverter control section 430 can control to output an output current of the second level Lvm2 larger than the first level Lvm1 from the inverter 420 in a state where the motor 230 is in the second connection method according to the action of the switching device 450.

[0208] Figure 10B (b) of FIG. 10 shows the switching voltage Sma corresponding to the output current ima output from the inverter 420 and the output voltage Smb as the effective voltage.

[0209] On the other hand, the output voltage Smb can correspond to the phase voltage.

[0210] During Pm1a in the Pm1 period, the pulse width of the switching voltage Sma is kept constant after rising, and the output voltage is kept at a third level Lvm3 after rising, and during Pm1b in the Pm1 period, the pulse width of the switching voltage Sma is kept constant again after rising, and the output voltage is kept at a fourth level Lvm4 again after rising.

[0211] During the Pms period after the Pm1 period, the output voltage is zero.

[0212] In a period Pm2a in the period Pm2 starting at a time Tm2 after the period Pms, the pulse width of the switching voltage Sma is held constant after rising, and the output voltage is held at a fifth level Lvm5 after rising. In a period Pm2b in the period Pm2, the pulse width of the switching voltage Sma is held constant again after rising, and the output voltage is held at a sixth level Lvm6 again after rising.

[0213] At this time, the fifth level Lvm5 can be smaller than the third level Lvm3, and the sixth level Lvm6 can be smaller than the fourth level Lvm4.

[0214] As Figure 10B (b), the control section 170 or the inverter control section 430 can calculate the first winding resistance in the first connection method and the second winding resistance in the second connection method according to the difference in the output voltage Smb in the first connection method and the second connection method.

[0215] In comparison with Figure 10A , it is possible to output output currents of various levels and calculate winding resistances based on this, so that it is possible to further improve the accuracy of the winding resistances calculated.

[0216] In particular, in comparison with Figure 10A , since it is possible to remove the influence that can be caused by components other than the stator resistance by outputting output currents of various levels, it is possible to further improve the accuracy of the winding resistances finally calculated.

[0217] On the other hand, since the output currents from the inverter 420 are the same, if the operation of the switching device 450 is normal, the first winding resistance whose level of the output voltage Smb is greater is greater than the second winding resistance.

[0218] Based on this characteristic, the control section 170 or the inverter control section 430 can determine whether or not the operation of the switching device 450 is abnormal.

[0219] On the other hand, in Figure 10B , one phase current ima is shown, but the control section 170 or the inverter control section 430 can also control so that the u-phase current, the v-phase current, and the w-phase current, which are output terminals of each phase of the inverter 420, have waveforms of Figure 10B in order, respectively.

[0220] Figure 11 is a simplified equivalent circuit diagram of the motor in the first connection method and the second connection method.

[0221] Referring to the drawings, Figure 11 (a) is a Y connection method as the first connection method, and shows an equivalent circuit diagram of the motor 230.

[0222] On the other hand, when the Va voltage is applied in the Y connection for controlling the current called Ia, the stator winding becomes 3 / 2 Ra.

[0223] Next, Figure 11 (b) is a Δ connection as the first connection, and shows an equivalent circuit diagram of the motor 230.

[0224] On the other hand, when the output current called Ia is output in the Δ connection, the Va is reduced to 1 / 3 as compared with the Y connection. This is because the winding resistance is reduced to 1 / 2 Ra.

[0225] Here, the control section 170 or the inverter control section 430 can determine whether the connection is properly changed by the switching device 450 using the difference.

[0226] Figure 12A is a graph showing the output voltage detected as the phase current of the first level and the second level is sequentially applied in the first connection and the second connection.

[0227] Referring to the drawings, in Figure 12A during Poa, an example is shown of the U-phase output current, the V-phase output current, the W-phase output current outputting the first level Lvm1 and the second level Lvm2 in the first connection, the U-phase output voltage during Poa1, the V-phase output voltage during Poa2, and the W-phase output voltage during Poa3.

[0228] As shown in the graph, the U-phase output voltage during Poa, the V-phase output voltage during Poa, and the W-phase output voltage during Poa can each have two voltage levels.

[0229] The control section 170 or the inverter control section 430 can calculate the first winding resistance of each phase U, V, and W in the first connection based on the phase U, V, and W output currents of the first level Lvm1 and the second level Lvm2 and the phase U, V, and W output voltages.

[0230] Next, during Pob of Figure 12A , an example is shown of the U-phase output current, the V-phase output current, the W-phase output current outputting the first level Lvm1 and the second level Lvm2 in the second connection, the U-phase output voltage during Pob1, the V-phase output voltage during Pob2, and the W-phase output voltage during Pob3.

[0231] As shown in the graph, the U-phase output voltage during Pob, the V-phase output voltage during Pob, and the W-phase output voltage during Pob can each have two voltage levels.

[0232] The control section 170 or the inverter control section 430 can calculate the second winding resistance of each phase U, V, W in the second connection method, based on the phase U, V, W output current and the phase U, V, W output voltage of the first level Lvm1 and the second level Lvm2.

[0233] Also, the control section 170 or the inverter control section 430 can determine whether or not the switching device 450 has an abnormality based on the first winding resistance of each phase U, V, W and the second winding resistance of each phase U, V, W.

[0234] Figure 12B is a graph showing the first winding resistance of each phase U, V, W and the second winding resistance of each phase U, V, W and their ratio in the case where the operation of the switching device 450 is normal.

[0235] Referring to the drawings, the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the first connection method can be 0.96, 0.96, and 0.97 Ω, respectively.

[0236] On the other hand, the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase can correspond to the winding resistance corresponding to the a-phase winding CA, the winding resistance corresponding to the b-phase winding CB, and the winding resistance corresponding to the c-phase winding CC, respectively. Figure 7

[0237] On the other hand, the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the second connection method can be 0.41, 0.42, and 0.42 Ω, respectively.

[0238] In this regard, the ratio of the winding resistance of the first connection method to the second connection method, that is, the winding resistance ratio of the U phase, the winding resistance ratio of the V phase, and the winding resistance ratio of the W phase can be 2.3, 2.3, and 2.3, respectively.

[0239] That is, in the case where the operation of the switching device 450 is normal, it is preferable that the first range as the normal range of the winding resistance in the first connection method is approximately 0.7 to 1.2 Ω, it is preferable that the second range as the normal range of the winding resistance in the second connection method is approximately 0.3 to 0.6 Ω, and it is preferable that the third range as the normal range of the winding resistance ratio of the first connection method to the second connection method can be approximately 2.0 to 2.5.

[0240] Based on such Figure 12B data, the control section 170 or the inverter control section 430 can determine whether or not the switching device 450 has an abnormality.

[0241] ​For example, the control section 170 or the inverter control section 430 can calculate the ratio of the first winding resistance and the second winding resistance for each phase U, V, and W, and determine that the switching device 450 is abnormal and control the winding of the motor 230 to operate in either the first connection method or the second connection method if the ratio of at least one of the calculated ratios deviates from a prescribed range. As described above, the motor 230 can be made to operate in an emergency by operating in only one of the connection method states when the switching device 450 is abnormal.

[0242] On the other hand, the control section 170 or the inverter control section 430 can calculate the first winding resistance and the second winding resistance for each phase U, V, and W, and determine that the motor 230 has failed if the range of the first winding resistance deviates from the first range in each phase U, V, and W and the range of the second winding resistance deviates from the second range in each phase U, V, and W. Thus, it is possible to simply determine whether the motor 230 has failed.

[0243] On the other hand, the control section 170 or the inverter control section 430 can calculate the first winding resistance and the second winding resistance for each phase U, V, and W, and determine that the switching device 450 is normal and control the switching device 450 to switch the winding of the motor 230 from the first connection method to the second connection method according to the operating frequency of the motor 230 if the range of the first winding resistance is within the first range in each phase U, V, and W and the range of the second winding resistance is within the second range in each phase U, V, and W. Thus, it is possible to improve the power conversion efficiency or the driving efficiency of the motor 230 when the switching device 450 is operating normally.

[0244] On the other hand, the control section 170 or the inverter control section 430 can calculate the first winding resistance and the second winding resistance for each phase U, V, and W, and determine that the switching device 450 is abnormal and control the winding of the motor 230 to operate in only the first connection method if the range of the first winding resistance is within the first range in each phase U, V, and W and the range of the second winding resistance deviates from the second range in each phase U, V, and W. As described above, the motor 230 can be made to operate in an emergency by operating in only one of the connection method states when the switching device 450 is abnormal.

[0245] On the other hand, the control section 170 or the inverter control section 430 can calculate the first winding resistance and the second winding resistance for each phase U, V, and W, and determine that the switching device 450 is abnormal and control the winding of the motor 230 to operate in only the second connection method if the range of the first winding resistance deviates from the first range in each phase U, V, and W and the range of the second winding resistance is within the second range in each phase U, V, and W. As described above, the motor 230 can be made to operate in an emergency by operating in only one of the connection method states when the switching device 450 is abnormal.

[0246] Figures 13A to 13C It is a diagram showing the resistance of the first winding of each phase U, V, and W and the resistance of the second winding of each phase U, V, and W, as well as their ratios, when switching from the first connection method to the second connection method.

[0247] first, Figure 13A (a) shows the equivalent circuit diagram of motor 230 in the event of an malfunction of a relay in switching device 450.

[0248] then, Figure 13A (b) indicates that in Figure 13A A diagram showing the resistance of the first winding and the resistances of the second windings for each phase U, V, and W in case (a), and their ratios.

[0249] Referring to the attached diagram, the winding resistances of phase U, phase V, and phase W in the first connection can be 0.97, 0.97, and 0.97 Ω, respectively.

[0250] On the other hand, in the second connection method, the winding resistance of phase U, phase V, and phase W can be 0.71, 0.41, and 0.72 Ω, respectively.

[0251] Regarding this, the ratio of the winding resistance of the first connection method to that of the second connection method, namely the winding resistance ratio of the U phase, the winding resistance ratio of the V phase, and the winding resistance ratio of the W phase, can be 1.4, 2.4, and 1.4, respectively.

[0252] Since the winding resistance ratio of the first connection method is within the third range of the normal range only for phase V compared to the second connection method, the control unit 170 or the inverter control unit 430 can determine that only the resistance ratio of phase V is normal, while the resistance ratios of phase U and phase W are abnormal.

[0253] On the other hand, since the winding resistance of phase U, phase V, and phase W in the first connection are all within the first range of the normal range, the control unit 170 or the inverter control unit 430 can determine that the operation in the first connection is normal.

[0254] On the other hand, since the winding resistance of phase U, phase V, and phase W in the second connection is within the second range of the normal range only in the case of phase V, but outside the second range in the cases of phase U and phase W, the control unit 170 or the inverter control unit 430 can determine that the operation in the second connection is abnormal.

[0255] Therefore, in Figure 13A In case (a), the control unit 170 or the inverter control unit 430 can be controlled to operate only in the first connection method instead of the second connection method by controlling the switching device 45.

[0256] Figure 13B (a) shows the equivalent circuit diagram of motor 230 in the event of abnormal operation of the two relays in switching device 450.

[0257] then, Figure 13B (b) indicates that in Figure 13B A diagram showing the resistance of the first winding and the resistances of the second windings for each phase U, V, and W in case (a), and their ratios.

[0258] Referring to the attached diagram, the winding resistances of phase U, phase V, and phase W in the first connection can be 0.89, 0.89, and 0.90 Ω, respectively.

[0259] On the other hand, in the second connection method, the winding resistance of phase U, phase V, and phase W can be 1.20, 0.47, and 0.64Ω, respectively.

[0260] Regarding this, the ratio of the winding resistance of the first connection method to that of the second connection method, namely the winding resistance ratio of the U phase, the winding resistance ratio of the V phase, and the winding resistance ratio of the W phase, can be 0.7, 1.9, and 1.4, respectively.

[0261] Since the winding resistance ratio of the first connection method is outside the normal range of the third range in all phases compared to the second connection method, the control unit 170 or the inverter control unit 430 can determine that the switching device 450 is malfunctioning.

[0262] On the other hand, since the winding resistance of phase U, phase V, and phase W in the first connection are all within the first range of the normal range, the control unit 170 or the inverter control unit 430 can determine that the operation in the first connection is normal.

[0263] On the other hand, since only the winding resistance of phase U, phase V, and phase W in the second connection is within the normal range in the case of phase V, while phases U and W are outside the range in the case of phase W, the control unit 170 or the inverter control unit 430 can determine that the operation in the second connection is abnormal.

[0264] Therefore, in Figure 13B In case (a), the control unit 170 or the inverter control unit 430 can control the switching device 450 to operate only in the first connection method and not the second connection method.

[0265] Figure 13C (a) shows the equivalent circuit diagram of motor 230 in the event of abnormal operation of the three relays in switching device 450.

[0266] then, Figure 13C(b) is a graph showing the first winding resistance of each phase U, V, W, the second winding resistance of each phase U, V, W, and their ratio when the switching device 450 is abnormal. Figure 13C (b) is a graph showing the first winding resistance of each phase U, V, W, the second winding resistance of each phase U, V, W, and their ratio when the switching device 450 is abnormal.

[0267] Referring to the drawings, the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the first connection method can be 0.97, 0.97, 0.97 Ω, respectively.

[0268] On the other hand, the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the second connection method can be 0.96, 0.98, 0.97 Ω, respectively.

[0269] In this regard, the ratio of the winding resistance of the first connection method to the second connection method, i.e., the winding resistance ratio of the U phase, the winding resistance ratio of the V phase, and the winding resistance ratio of the W phase can be 1.0, 0.99, 1.0, respectively.

[0270] Since the winding resistance ratio of the first connection method to the second connection method, in the third range in which all the phases are out of the normal range, the control portion 170 or the inverter control portion 430 can determine that the switching device 450 is abnormal.

[0271] On the other hand, since the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the first connection method are all within the first range in the normal range, the control portion 170 or the inverter control portion 430 can determine that the operation in the first connection method is normal.

[0272] On the other hand, since the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the second connection method are all out of the second range in the normal range, the control portion 170 or the inverter control portion 430 can determine that the operation in the second connection method is abnormal.

[0273] Thus, in the case of (a) of FIG. 8, Figure 13C (b) is a graph showing the first winding resistance of each phase U, V, W, the second winding resistance of each phase U, V, W, and their ratio when the switching device 450 is abnormal.

[0274] Figures 14A to 14C (b) is a graph showing the first winding resistance of each phase U, V, W, the second winding resistance of each phase U, V, W, and their ratio when the switching device 450 is abnormal.

[0275] First, Figure 14A (a) of FIG. 8 shows an equivalent circuit diagram of the motor 230 in the case where the operation of one relay in the switching device 450 is abnormal.

[0276] Next, Figure 14A (b) is a graph showing the first winding resistance of each phase U, V, W, the second winding resistance of each phase U, V, W, and their ratio when the switching device 450 is abnormal. Figure 14AA diagram showing the resistance of the first winding, the resistance of the second winding of each phase U, V, W, and their ratios in case (a).

[0277] Referring to the attached diagram, the winding resistances of phase U, phase V, and phase W in the first connection can be 1.23, 0.48, and 0.67 Ω, respectively.

[0278] On the other hand, in the second connection method, the winding resistance of phase U, phase V, and phase W can be 0.40, 0.40, and 0.40Ω, respectively.

[0279] Regarding this, the ratio of the winding resistance of the first connection method to that of the second connection method, namely the winding resistance ratio of the U phase, the winding resistance ratio of the V phase, and the winding resistance ratio of the W phase, can be 3.1, 1.2, and 1.7, respectively.

[0280] Since the winding resistance ratio of the first connection method is outside the normal range of the third range for all phases compared to the second connection method, the control unit 170 or the inverter control unit 430 can determine that the switching device 450 is malfunctioning.

[0281] On the other hand, since the winding resistance of phase U, phase V, and phase W in the first connection are all outside the normal range, the control unit 170 or the inverter control unit 430 can determine that the operation in the first connection is abnormal.

[0282] On the other hand, since the winding resistance of phase U, phase V, and phase W in the second connection are all within the second range of the normal range, the control unit 170 or the inverter control unit 430 can determine that the operation in the second connection is normal.

[0283] Therefore, in Figure 14A In case (a), the control unit 170 or the inverter control unit 430 can control the switching device 450 to operate only in the second connection method instead of the first connection method.

[0284] Figure 14B (a) shows the equivalent circuit diagram of motor 230 in the event of abnormal operation of the two relays in switching device 450.

[0285] then, Figure 14B (b) is shown in Figure 14B A diagram showing the resistance of the first winding, the resistance of the second winding of each phase U, V, W, and their ratios in case (a).

[0286] Referring to the attached diagram, the winding resistances of phase U, phase V, and phase W in the first connection can be 0.68, 0.68, and 0.41 Ω, respectively.

[0287] On the other hand, the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the second connection method can be 0.4, 0.4, and 0.41 Ω, respectively.

[0288] Regarding this, the ratio of the winding resistance of the first connection method to the winding resistance of the second connection method, that is, the winding resistance ratio of the U phase, the winding resistance ratio of the V phase, and the winding resistance ratio of the W phase can be 1.7, 1.7, and 1.0, respectively.

[0289] Due to the winding resistance ratio of the first connection method to the winding resistance of the second connection method, in the third range in which all the phases are out of the normal range, the control unit 170 or the inverter control unit 430 can determine that the switching device 450 is abnormal.

[0290] On the other hand, due to the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the first connection method all being in the first range out of the normal range, the control unit 170 or the inverter control unit 430 can determine that the operation in the first connection method is abnormal.

[0291] On the other hand, due to the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the second connection method all being in the second range within the normal range, the control unit 170 or the inverter control unit 430 can determine that the operation in the second connection method is normal.

[0292] Thus, in the case of (a) of the above-mentioned (1), Figure 14B the control unit 170 or the inverter control unit 430 can control, by controlling the switching device 450, to operate only in the second connection method and not in the first connection method.

[0293] Figure 14C (a) of the above-mentioned (1) shows an equivalent circuit diagram of the motor 230 in a case where the operation of the three relays in the switching device 450 is abnormal.

[0294] Next, Figure 14C (b) of the above-mentioned (1) is a graph showing the first winding resistance, the second winding resistance of each phase U, V, and W, and the ratio thereof in the case of (a) of the above-mentioned (1). Figure 14C Referring to the drawings, the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the first connection method can be 0.39, 0.41, and 0.41 Ω, respectively.

[0295] On the other hand, the winding resistance of the U phase, the winding resistance of the V phase, and the winding resistance of the W phase in the second connection method can be 0.4, 0.4, and 0.41 Ω, respectively.

[0296]

[0297] ​Regarding this, the ratio of the winding resistance of the first connection method to that of the second connection method, namely the winding resistance ratio of the U phase, the winding resistance ratio of the V phase, and the winding resistance ratio of the W phase, can be 0.98, 1.0, and 1.0, respectively.

[0298] Since the winding resistance ratio of the first connection method is outside the normal range of the third range in all phases compared to the second connection method, the control unit 170 or the inverter control unit 430 can determine that the switching device 450 is malfunctioning.

[0299] On the other hand, since the winding resistance of phase U, phase V, and phase W in the first connection are all outside the normal range, the control unit 170 or the inverter control unit 430 can determine that the operation in the first connection is abnormal.

[0300] On the other hand, since the winding resistance of phase U, phase V, and phase W in the second connection are all within the second range of the normal range, the control unit 170 or the inverter control unit 430 can determine that the operation in the second connection is normal.

[0301] Therefore, in Figure 14C In case (a), the control unit 170 or the inverter control unit 430 can control the switching device 450 to operate only in the second connection method instead of the first connection method.

[0302] Figure 15 This is a flowchart illustrating an operation method of a motor drive device according to another embodiment of the present invention. Figures 16A to 16C This is an explanation Figure 15 The action is referenced in the diagram.

[0303] Reference Figure 15 , Figure 15 The operation method and Figure 9A The operation method is similar, except that after step 930 (S930), steps 950 (S950) to 965 (S965) are also executed.

[0304] Therefore, steps 910 (S910), 920 (S920), and 930 (S930) refer to Figure 9A Explanation.

[0305] On the other hand, although only steps 910 (S910), 920 (S920), and 930 (S930) are illustrated in the accompanying drawings, the drawings are not limited to these steps and may be executed in other ways as well. Figure 9B After steps 910 (S910), 920 (S920), 922 (S922), 930 (S930), and 932 (S932), step 950 (S950) is executed.

[0306] On the other hand, the control section 170 or the inverter control section 430 calculates the first winding resistance in the first connection method and the second winding resistance in the second connection method. In particular, the first winding resistance in the first connection method and the second winding resistance in the second connection method can be calculated for each of the phases U, V, and W.

[0307] Next, the control section 170 or the inverter control section 430 determines whether the first winding resistance is within the first range and the second winding resistance is within the second range (S950).

[0308] As described above, the first range can be 0.7 to 1.2, and the second range can be 0.3 to 0.6.

[0309] Next, in a case where the first winding resistance is within the first range and the second winding resistance is within the second range, the control section 170 or the inverter control section 430 can control the switching device 450 to switch the winding of the motor 230 from the first connection method to the second connection method in accordance with the operating frequency of the motor 230 (S952).

[0310] Thus, the power conversion efficiency or the driving efficiency of the motor 230 can be improved in a case where the switching device 450 is normally operating.

[0311] On the other hand, during the switching of the winding of the motor 230 from the first connection method to the second connection method by the switching device 450, the control section 170 or the inverter control section 430 can control the motor 230 to continue operating without stopping. As described above, since the motor 230 does not stop when the switching device 450 performs the switching operation, the operating efficiency of the motor 230 can be improved.

[0312] On the other hand, during the switching of the winding of the motor 230 from the first connection method to the second connection method by the switching device 450, the control section 170 or the inverter control section 430 can control the operating frequency of the motor 230 to be lowered from the first frequency to the second frequency and then to be raised again. As described above, since the motor 230 does not stop when the switching device 450 performs the switching operation, the operating efficiency of the motor 230 can be improved.

[0313] On the other hand, in a case where the step 950 (S950) is not satisfied, the control section 170 or the inverter control section 430 determines whether the first winding resistance is within the first range and the second winding resistance is out of the second range (S955).

[0314] Further, in a case where the first winding resistance is within the first range and the second winding resistance is out of the second range, the control portion 170 or the inverter control portion 430 can control the switching device 450 to act only in the first connection and not in the second connection (S957). As described above, in a case where the switching device 450 is abnormal, the switching device 450 acts only in one of the connection states, and thus the motor 230 can be made to operate in an emergency.

[0315] On the other hand, in a case where the step 955 is not satisfied (S955), the control portion 170 or the inverter control portion 430 determines whether the first winding resistance is out of the first range and the second winding resistance is within the second range (S960).

[0316] Further, in a case where the first winding resistance is out of the first range and the second winding resistance is within the second range, the control portion 170 or the inverter control portion 430 can control the switching device 450 to act only in the second connection and not in the first connection (S962). As described above, in a case where the switching device 450 is abnormal, the switching device 450 acts only in one of the connection states, and thus the motor 230 can be made to operate in an emergency.

[0317] On the other hand, in a case where the step 960 is not satisfied (S960), the control portion 170 or the inverter control portion 430 determines that the first winding resistance is out of the first range and the second winding resistance is out of the second range, and determines that the motor 230 has failed (S965). Thus, it is possible to easily determine whether the motor 230 has failed.

[0318] Further, in a case where the motor 230 has failed, the control portion 170 or the inverter control portion 430 not only stops the operation of the motor 230 but also stops the operation of the inverter 420 and the like, and thus it is possible to prevent the circuit elements in the motor drive device 220 from being damaged and the like.

[0319] Figure 16A Various examples of the equivalent circuit diagram of the motor 230 in a case where the first winding resistance is within the first range and the second winding resistance is within the second range are shown.

[0320] Figure 16A (a) of FIG. 10 shows an equivalent circuit diagram of the motor 230 in the first connection as the Y connection, Figure 16A (b) of FIG. 10 shows an equivalent circuit diagram of the motor 230 in the second connection as the Δ connection.

[0321] As Figure 15 In the step 952 (S952) of FIG. 9, the control portion 170 or the inverter control portion 430 can control to switch between the first connection and the second connection in accordance with the operating frequency of the motor 230.

[0322] Figure 16BVarious examples of equivalent circuit diagrams of motor 230 are shown, where the resistance of the first winding is within a first range and the resistance of the second winding is outside a second range.

[0323] Figure 16B (a) and as Figure 13C The three relay components correspond to abnormal situations. Figure 16B (b) and such Figure 13B The two relay components are abnormal, corresponding to the following situations. Figure 16B (c) and such Figure 13A This corresponds to a situation where a relay element malfunctions.

[0324] Therefore, in Figure 16B In such cases, the control unit 170 or the inverter control unit 430 can control the switching device 450 to operate only in the first connection method and not in the second connection method.

[0325] Figure 16C Various examples of equivalent circuit diagrams of motor 230 are shown, where the first winding resistance is outside the first range and the second winding resistance is within the second range.

[0326] Figure 16C (a) and as Figure 13C The three relay components correspond to abnormal situations. Figure 16C (b) and such Figure 13B The two relay components are abnormal, corresponding to the following situations. Figure 16C (c) and such Figure 13A This corresponds to a situation where a relay element malfunctions.

[0327] Therefore, in Figure 16C In such cases, the control unit 170 or the inverter control unit 430 can control the switching device 450 to operate only in the second connection method and not in the first connection method.

[0328] On the other hand, in order to prevent the switching device 450 from malfunctioning due to its shortened lifespan caused by repeated use, the present invention can perform operation that restricts connection switching.

[0329] Specifically, if, within a specified time period under the second connection state, the number of times the motor 230 operates at a low speed abnormally at an operating frequency below the limit exceeds a first critical value, the control unit 170 can restrict the connection switching of the motor 230 windings. Therefore, no pressure is applied to the switching device 450, preventing malfunction of the switching device 450. Here, the specified time can be a pre-set time.

[0330] Here, restricting the switching of the winding connection of the motor 230 means that the switching device 450 will not switch to the first connection or the second connection, but will remain in the second connection state.

[0331] In the limit state that limits the change of the connection state of the winding of the motor 230, the control portion 170 can allow the change of the connection of the winding of the motor 230 after the lapse of the first time. In the limit state that limits the change of the connection state of the winding of the motor 230, the control portion 170 can initialize the cumulative value of the number of times of low-speed abnormal operation after the lapse of the first time. Instead of keeping the connection state change limit without limit, the connection change is allowed again after the lapse of the prescribed time, and thus it is expected that the efficiency of the compressor is improved.

[0332] In the limit frequency condition, the output current value in the first connection state can be smaller than the output current value in the second connection state. In the limit frequency condition, the output current value in the first connection state can be smaller than 1 / √3 times the maximum value of the output current in the second connection state.

[0333] In addition, the limit frequency can be defined as the frequency at which the output current value in the first connection state is smaller than the output current value in the second connection state and the output current value in the first connection state is smaller than 1 / √3 times the maximum value of the output current in the second connection state.

[0334] If the number of times of low-speed abnormal operation of the motor 230 in the second connection state at a frequency lower than the limit frequency within the prescribed time is smaller than the first critical value, the control portion 170 can control the winding of the motor 230 to be switched to the first connection or maintained in the second connection according to the operating frequency of the motor 230.

[0335] Specifically, if the number of times of low-speed abnormal operation of the motor 230 in the second connection state at a frequency lower than the limit frequency within the prescribed time is smaller than the first critical value, the control portion 170 can control the winding of the motor 230 to be in the first connection state when the operating frequency of the motor 230 is lower than the first operating frequency and to be maintained in the second connection state when the operating frequency of the motor 230 exceeds the first operating frequency.

[0336] As another example, if the number of times of low-speed abnormal operation of the motor 230 in the second connection state at a frequency lower than the limit frequency within the prescribed time is smaller than the first critical value, the control portion 170 can control the winding of the motor 230 to be switched to the first connection or maintained in the second connection according to the operating speed of the motor 230.

[0337] Specifically, if the number of low-speed abnormal operations in which the motor 230 operates at an operating frequency below the limit frequency within a prescribed time is less than the first threshold value in the second connection state, the control section 170 can control to make the winding of the motor 230 into the first connection state in a case where the operating speed of the motor 230 is below the first speed, and to keep the winding of the motor 230 in the second connection state in a case where the operating speed of the motor 230 exceeds the first speed.

[0338] Hereinafter, the operation method of the motor driving device 220 will be described in detail with reference to the flowchart shown in FIG. 6. Figure 17

[0339] Figure 17 is a flowchart showing the operation method of the motor driving device 220 according to another embodiment of the present application. Figure 17 FIG. 7 shows a graph of the operation of the limit connection state transition.

[0340] Referring to FIG. 6, Figure 17 In the operation method of the motor driving device 220 according to the embodiment of the present application, Figure 17 In the operation method of the motor driving device 220 according to the embodiment of the present application, the order of the step 160 (S160) and the step 170 (S170) can be exchanged with each other.

[0341] First, the control section 170 determines whether the winding of the motor 230 is in the second connection state (S110). If it is determined that the winding of the motor 230 is not in the second connection state, the control section 170 ends the execution of the connection state transition limit operation.

[0342] Thereafter, if it is determined that the winding of the motor 230 is in the second connection state, the control section 170 counts the number of low-speed abnormal operations (S120).

[0343] Thereafter, the control section 170 determines whether the number of low-speed abnormal operations exceeds the first threshold value within a prescribed time (S130). If the number of low-speed abnormal operations in which the motor 230 operates at an operating frequency below the limit frequency within the prescribed time exceeds the first threshold value, the control section 170 limits the connection state transition of the winding of the motor 230 (S140). Of course, if the number of low-speed abnormal operations does not exceed the first threshold value within the prescribed time, the control section 170 allows the connection state transition of the winding of the motor 230.

[0344] Thereafter, the control section 170 determines whether the first time has elapsed since the connection state of the winding of the motor 230 is changed (S150).

[0345] Thereafter, in a case where it is determined that the first time has elapsed, the control section 170 allows the connection state transition of the winding of the motor 230 (S160).

[0346] ​After that, in a case where it is determined that the first time has elapsed, the control unit 170 initializes the accumulated value of the low-speed abnormal operation number (S170).

[0347] On the other hand, in Figures 4 to 17 The motor drive device 220 of the embodiment of the present application described above can be applied to various home appliances in addition to the air conditioner 100. Figure 1 For example, it can be applied to various fields such as a laundry processing apparatus (a washing machine, a dryer, etc.), a refrigerator, a water purifier, a robot cleaner, a robot, a vehicle, a drone, etc.

[0348] On the other hand, the motor drive device or the operation method of the air conditioner of the present application can be implemented in a processor-readable code in a storage medium which is readable by a processor provided in the motor drive device or the air conditioner. The processor-readable storage medium includes all types of recording devices which store data readable by a processor. Examples of the processor-readable storage medium are a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc., and in addition, it includes implementation in a form of a carrier wave, for example, transmission based on the Internet. In addition, the processor-readable storage medium can be dispersed in a computer system connected through a network, and the processor-readable code can be stored and executed in a dispersed manner.

[0349] In the motor drive device of the embodiment of the present application and the air conditioner including the same, if the low-speed abnormal operation number of the motor operating at an operation frequency below the limit frequency for a predetermined time exceeds the first critical value in the second connection state, the condition in which the switching device is repeatedly used is prevented by limiting the connection conversion of the winding of the motor, so that the shortening of the life and the malfunction due to the repeated use of the switching device can be prevented.

[0350] In addition, the present application can reduce the control burden of the controller, perform rapid control, and prevent the performance of the air conditioner from being degraded because the present application determines the low-speed abnormal operation number only to determine the connection conversion of the motor.

[0351] Because the present application can determine whether the switching device which converts the connection of the motor has an abnormality, it can rapidly recognize the abnormality of the switching device, and can prevent other air conditioner devices from malfunctioning due to the malfunction of the switching device.

[0352] In addition, because the present application determines whether the switching device has an abnormality based on the winding resistance of the motor in the first connection and the winding resistance of the motor in the second connection, it can simply determine whether the switching device has an abnormality based on the resistance.

[0353] In addition, the preferred embodiments of the present application have been illustrated and described, but the present application is not limited to the specific embodiments described above, and those skilled in the art can obviously make various modifications without departing from the spirit of the present application claimed in the claims, and such modifications should not be separately understood as departing from the technical idea or prospect of the present application.

Claims

1. A motor drive apparatus characterized by comprising: Comprising: an inverter provided with a plurality of switching devices, which outputs an alternating-current power to a motor based on switching operations; a switching device configured between the inverter and the motor, which converts a winding of the motor to a first connection method or a second connection method; a control unit which controls the inverter and the switching device; if, in the state of the second connection method, a number of low-speed abnormal operations in which the motor operates at an operating frequency below a limit frequency within a prescribed time exceeds a first threshold value, the control unit restricts conversion of the connection method of the winding of the motor; the control unit determines whether an abnormality occurs in the operation of the switching device based on a first winding resistance of the motor in the first connection method and a second winding resistance of the motor in the second connection method.

2. The motor drive device according to claim 1, wherein in the connection method state change restriction state of the winding of the motor, after a first time elapses, the control unit allows conversion of the connection method of the winding of the motor.

3. The motor drive device according to claim 1, wherein in the connection method state change restriction state of the winding of the motor, after a first time elapses, the control unit initializes a cumulative value of the number of low-speed abnormal operations.

4. The motor drive device according to claim 1, further comprising an output current detection unit which detects an output current output from the inverter, in the limit frequency, an output current value in the state of the first connection method is smaller than an output current value in the state of the second connection method.

5. The motor drive device according to claim 4, wherein 6. The motor drive device according to claim 1, wherein in a case where the operating frequency of the motor is below a first operating frequency, the control unit controls so that the winding of the motor is in the state of the first connection method. At the limit frequency, the output current value in the state of the first connection method is less than the highest value of the output current in the state of the second connection method by a factor of two.

7. The motor drive device according to claim 1, wherein in a case where the operating frequency of the motor exceeds a first operating frequency, the control unit controls so that the winding of the motor is in the state of the second connection method.

8. The motor drive device according to claim 1, wherein during conversion of the winding of the motor from the first connection method to the second connection method, the control unit controls so that the motor does not stop and continues to operate.

9. The motor drive device according to claim 1, wherein if, in the state of the second connection method, a number of low-speed abnormal operations in which the motor operates at an operating frequency below a limit frequency within a prescribed time is smaller than a first threshold value, the control unit converts the winding of the motor to the first connection method or maintains the second connection method in accordance with the operating frequency of the motor.

10. The motor drive device according to claim 1, wherein if, in the state of the second connection method, a number of low-speed abnormal operations in which the motor operates at an operating frequency below a limit frequency within a prescribed time is smaller than a first threshold value, the control unit converts the winding of the motor to the first connection method or maintains the second connection method in accordance with the operating speed of the motor. ​ ​ 11. The motor drive apparatus according to claim 10, wherein the control section controls the winding of the motor to be in the first connection when the operating speed of the motor is equal to or lower than a first speed.

12. The motor drive apparatus according to claim 10, wherein the control section controls the winding of the motor to be in the second connection when the operating speed of the motor exceeds the first speed.

13. The motor drive apparatus according to claim 1, further comprising an output current detection section that detects an output current output from the inverter, wherein if the winding of the motor is in the first connection according to the operation of the switching device during a first period in accordance with the check mode of the switching device, the control section controls the output current output from the inverter to be a first level, if the winding of the motor is in the second connection according to the operation of the switching device during a second period after the first period, the control section controls the output current output from the inverter to be the first level.

14. The motor drive apparatus according to claim 1, wherein the control section calculates the first winding resistance and the second winding resistance for each phase, if the range of the first winding resistance for each phase deviates from a first range and the range of the second winding resistance for each phase deviates from a second range, the control section determines that the motor has failed, if the range of the first winding resistance for each phase is within the first range and the range of the second winding resistance for each phase is within the second range, the control section determines that the switching device is normal, and controls the switching device to switch the winding of the motor from the first connection to the second connection in accordance with the operating frequency of the motor.

15. An air conditioner, comprising the motor drive apparatus according to any one of claims 1 to 14. ​ ​

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