Refrigeration cycle device

Abstract

Provided is a refrigeration cycle device that is able to suppress disproportionation reactions of a working medium. A refrigeration cycle device (1) includes a compressor (4) and comprises a control device (3) that controls a refrigeration cycle circuit in which a working medium circulates. The working medium includes an ethylene-based fluoroolefin as a refrigerant component. The compressor (4) comprises a sealed vessel (40) that constitutes a flow path for the working medium, a compression mechanism (41) located inside the sealed vessel (40), and an electric motor (42). The control device (3) has a drive circuit (31) that drives the electric motor (42), a detection circuit (32) that detects insulation deterioration of the windings of the electric motor (42), and a control circuit (33) that: has a first control mode for controlling the refrigeration cycle circuit under a first condition, and a second control mode for controlling the refrigeration cycle circuit under a second condition in which at least one of the maximum pressure and the maximum temperature of the working medium in the compressor (4) is lower than in the first condition; and selects the second control mode when insulation deterioration of the windings of the motor (42) has been detected in the detection circuit (32).

Description

Refrigeration cycle equipment

[0001] The present disclosure relates to a refrigeration cycle device.

[0002] Conventionally, R410A has been widely used as a working fluid (heat medium, refrigerant) for refrigeration cycle devices. However, R410A has a high global warming potential (GWP) of 2090. Therefore, from the perspective of preventing global warming, research and development has been conducted on working fluids with lower GWP. Patent Document 1 discloses 1,1,2-trifluoroethylene (HFO1123) as a working fluid with a lower GWP than R410A. Patent Document 2 discloses 1,2-difluoroethylene (HFO1132) as a working fluid with a lower GWP than R410A.

[0003] International Publication No. WO 2012 / 157764 International Publication No. WO 2012 / 157765

[0004] In particular, HFO1123 and HFO1132 have a smaller GWP than R410A, but this makes them less stable than R410A. For example, the generation of radicals can cause disproportionation reactions of HFO1123 or HFO1132, which can change HFO1123 and HFO1132 into other compounds.

[0005] The present disclosure provides a refrigeration cycle device that makes it possible to suppress the disproportionation reaction of a working fluid.

[0006] A refrigeration cycle device according to one aspect of the present disclosure includes a refrigeration cycle circuit including a compressor, a condenser, an expansion valve, and an evaporator, through which a working medium circulates, and a control device that controls the refrigeration cycle circuit. The working medium includes an ethylene-based fluoroolefin as a refrigerant component. The compressor includes a sealed container that forms a flow path for the working medium, a compression mechanism located within the sealed container that compresses the working medium, and an electric motor located within the sealed container that operates the compression mechanism. The control device includes a drive circuit that drives the electric motor, a detection circuit that detects insulation deterioration of a winding of the electric motor, and a control circuit that has a first control mode that controls the refrigeration cycle circuit under a first condition and a second control mode that controls the refrigeration cycle circuit under a second condition in which at least one of the maximum pressure and maximum temperature of the working medium in the compressor is lower than the first condition, and that selects the second control mode when insulation deterioration of the winding of the electric motor is detected by the detection circuit.

[0007] Aspects of the present disclosure enable the suppression of disproportionation reactions of the working medium.

[0008] 1 is a block diagram of an example of the configuration of a refrigeration cycle device according to one embodiment; FIG. 2 is a schematic diagram of an example of the configuration of a compressor and a control device of the refrigeration cycle device of FIG. 1; FIG. 3 is a flowchart of an example of the operation of the control circuit of the control device of FIG. 2;

[0009] [1. Embodiments] Hereinafter, embodiments of the present disclosure will be described, with reference to the drawings where appropriate. However, the following embodiments are merely examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. Positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Each figure described in the following embodiments is a schematic diagram, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the dimensional ratios of each element are not limited to the ratios shown in the drawings.

[0010] In the following description, when it is necessary to distinguish between multiple components, prefixes such as "first" and "second" are added to the names of the components. However, when the components can be distinguished from each other by the symbols attached to them, the prefixes such as "first" and "second" may be omitted in consideration of readability of the text.

[0011] [1.1 Configuration] Fig. 1 is a block diagram of a configuration example of a refrigeration cycle device 1 according to this embodiment. The refrigeration cycle device 1 in Fig. 1 configures, for example, an air conditioner capable of cooling operation and heating operation.

[0012] The refrigeration cycle device 1 in FIG. 1 includes a refrigeration cycle circuit 2 and a control device 3 .

[0013] The refrigeration cycle circuit 2 constitutes a flow path through which the working medium circulates. In this embodiment, the working medium contains an ethylene-based fluoroolefin as a refrigerant component. The ethylene-based fluoroolefin is preferably an ethylene-based fluoroolefin that undergoes a disproportionation reaction. Examples of ethylene-based fluoroolefins that undergo a disproportionation reaction include 1,1,2-trifluoroethylene (HFO1123), trans-1,2-difluoroethylene (HFO1132(E)), cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), and tetrafluoroethylene (CF ２ =CF ２ , FO1114), and monofluoroethylene (HFO-1141).

[0014] The working fluid may contain multiple types of refrigerant components. The working fluid may contain an ethylene-based fluoroolefin as a main refrigerant component and a compound other than an ethylene-based fluoroolefin as a secondary refrigerant component. Examples of the secondary refrigerant component include hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), saturated hydrocarbons, carbon dioxide, etc. Examples of hydrofluorocarbons (HFCs) include difluoromethane, difluoroethane, trifluoroethane, tetrafluoroethane, pentafluoroethane, pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, heptafluorocyclopentane, etc. Examples of hydrofluoroolefins (HFOs) include monofluoropropene, trifluoropropene, tetrafluoropropene, pentafluoropropene, hexafluorobutene, etc. Examples of saturated hydrocarbons include ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methylpropane), methylcyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2,2-dimethylpropane), methylcyclobutane, and the like.

[0015] The working fluid may further contain a disproportionation inhibitor that suppresses the disproportionation reaction of the ethylenic fluoroolefin. Examples of disproportionation inhibitors include saturated hydrocarbons or haloalkanes. Examples of saturated hydrocarbons include ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methylpropane), methylcyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2,2-dimethylpropane), methylcyclobutane, and the like. Of the above examples, n-propane is preferred. Examples of haloalkanes include haloalkanes having 1 or 2 carbon atoms. Examples of haloalkanes having 1 carbon atom (i.e., halomethanes) include (mono)iodomethane (CH ３ I), diiodomethane (CH ２ I ２ ), dibromomethane (CH ２ Br ２ ), bromomethane (CH ３Br), dichloromethane (CH ２ Cl ２ ), chloroiodomethane (CH ２ ClI), dibromochloromethane (CHBr ２ Cl), tetraiodomethane (Cl ４ ), carbon tetrabromide (CBr ４ ), bromotrichloromethane (CBrCl ３ ), dibromodichloromethane (CBr ２ Cl ２ ), tribromofluoromethane (CBr ３ F), fluorodiiodomethane (CHFI ２ ), difluorodiiodomethane (CF ２ I ２ ), dibromodifluoromethane (CBr ２ F ２ ), trifluoroiodomethane (CF ３ Examples of haloalkanes having two carbon atoms (i.e., haloethanes) include 1,1,1-trifluoro-2-iodoethane (CF ３ CH ２ I), monoiodoethane (CH ３ CH ２ I), monobromoethane (CH ３ CH ２ Br), 1,1,1-triiodoethane (CH ３ CI ３ The working fluid may contain one or more haloalkanes having 1 or 2 carbon atoms. That is, only one type of haloalkane having 1 or 2 carbon atoms may be used, or two or more types may be used in appropriate combination.

[0016] The refrigeration cycle circuit 2 in FIG. 1 includes a compressor 4 , a first heat exchanger 5 , an expansion valve 6 , a second heat exchanger 7 , and a four-way valve 8 .

[0017] The refrigeration cycle apparatus 1 in Fig. 1 includes an outdoor unit 1a and an indoor unit 1b. The outdoor unit 1a includes a control device 3, a compressor 4, a first heat exchanger 5, an expansion valve 6, and a four-way valve 8. The first heat exchanger 5 exchanges heat between outdoor air and a working medium 20. The outdoor unit 1a further includes a first blower 5a for promoting heat exchange in the first heat exchanger 5. The indoor unit 1b includes a second heat exchanger 7. The second heat exchanger 7 exchanges heat between indoor air and the working medium 20. The indoor unit 1b further includes a second blower 7a for promoting heat exchange in the second heat exchanger 7.

[0018] In the refrigeration cycle circuit 2 of Fig. 1, the compressor 4 compresses the working medium to increase its pressure. The compressor 4 will be described in detail later. The first heat exchanger 5 and the second heat exchanger 7 exchange heat between the working medium circulating through the refrigeration cycle circuit 2 and external air (e.g., outside air or room air). The expansion valve 6 adjusts the pressure (evaporation pressure) of the working medium and the flow rate of the working medium. The four-way valve 8 switches the direction of the working medium circulating through the refrigeration cycle circuit 2 between a first direction corresponding to cooling operation and a second direction corresponding to heating operation.

[0019] In this embodiment, the first direction is the direction in which the working medium circulates through the refrigeration cycle circuit 2, in the order of the compressor 4, the first heat exchanger 5, the expansion valve 6, and the second heat exchanger 7, as indicated by the solid arrow A1 in FIG. 1 .

[0020] During cooling operation, the compressor 4 compresses and discharges the gaseous working medium, which is then sent to the first heat exchanger 5 via the four-way valve 8. The first heat exchanger 5 exchanges heat between the outside air and the gaseous working medium, causing the gaseous working medium to condense and liquefy. The liquid working medium is decompressed by the expansion valve 6 and sent to the second heat exchanger 7. The second heat exchanger 7 exchanges heat between the liquid working medium and the indoor air, causing the gaseous working medium to evaporate and become a gaseous working medium. The gaseous working medium returns to the compressor 4 via the four-way valve 8. During cooling operation, the first heat exchanger 5 functions as a condenser, and the second heat exchanger 7 functions as an evaporator. Therefore, during cooling, the indoor unit 1b blows air cooled by heat exchange in the second heat exchanger 7 into the room.

[0021] In this embodiment, the second direction is the direction in which the working medium circulates through the refrigeration cycle circuit 2, in the order of the compressor 4, the second heat exchanger 7, the expansion valve 6, and the first heat exchanger 5, as indicated by the dashed arrow A2 in FIG.

[0022] During heating operation, the compressor 4 compresses and discharges the gaseous working medium, which is then sent to the second heat exchanger 7 via the four-way valve 8. The second heat exchanger 7 exchanges heat between the room air and the gaseous working medium, causing the gaseous working medium to condense and liquefy. The liquid working medium is decompressed by the expansion valve 6 and sent to the first heat exchanger 5. The first heat exchanger 5 exchanges heat between the liquid working medium and outside air, causing the gaseous working medium to evaporate and become a gaseous working medium. The gaseous working medium returns to the compressor 4 via the four-way valve 8. During heating operation, the first heat exchanger 5 functions as an evaporator, and the second heat exchanger 7 functions as a condenser. Therefore, during heating, the indoor unit 1b blows air heated by heat exchange in the second heat exchanger 7 into the room.

[0023] The control device 3 in Fig. 1 controls the refrigeration cycle circuit 2. More specifically, the control device 3 controls the compressor 4, the first blower 5a, the expansion valve 6, the second blower 7a, and the four-way valve 8 of the refrigeration cycle circuit 2. Fig. 2 is a schematic diagram of an example configuration of the compressor 4 and the control device 3.

[0024] The compressor 4 is, for example, a hermetic compressor. The compressor 4 may be a rotary type, a scroll type, or any other known type. The compressor 4 in FIG. 2 includes a hermetic container 40, a compression mechanism 41, and an electric motor 42.

[0025] The sealed container 40 in Fig. 2 forms a flow path for the working medium 20. The sealed container 40 has a suction pipe 401 and a discharge pipe 402. The working medium 20 is drawn into the sealed container 40 from the suction pipe 401, compressed by the compression mechanism 41, and then discharged from the discharge pipe 402 to the outside of the sealed container 40. The inside of the sealed container 40 is filled with the high-temperature and high-pressure working medium 20 and lubricating oil. The bottom of the sealed container 40 forms an oil reservoir that stores a mixture of the working medium 20 and lubricating oil.

[0026] The compression mechanism 41 is located inside the sealed container 40 and compresses the working medium 20. The compression mechanism 41 may have a conventionally known configuration. The compression mechanism 41 has, for example, a cylinder that forms a compression chamber, a rolling piston that is disposed in the compression chamber inside the cylinder, and a crankshaft that is coupled to the rolling piston.

[0027] The electric motor 42 is located within the sealed container 40 and drives the compression mechanism 41. The electric motor 42 is, for example, a brushless motor (three-phase brushless motor). FIG. 3 is a schematic diagram of an example configuration of the electric motor 42 and the control device 3. As shown in FIG. 3, the electric motor 42 has multiple windings (stator windings) Lu, Lv, and Lw. The multiple windings include a U-phase winding Lu, a V-phase winding Lv, and a W-phase winding Lw. The electric motor 42 includes, for example, a rotor fixed to the crankshaft of the compression mechanism 41 and a stator disposed around the rotor. The stator is configured, for example, by windings (such as magnet wire) Lu, Lv, and Lw in a concentrated or distributed manner around a stator core (such as an electromagnetic steel plate) with insulating paper interposed therebetween. The windings Lu, Lv, and Lw are covered with an insulating member. Examples of insulating materials include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), aramid polymer, polyphenylene sulfide (PPS), and the like.

[0028] The compressor 4 may include an accumulator to prevent liquid compression in the compression chamber of the compression mechanism 41. The accumulator separates the working medium 20 into a gaseous working medium 20 and a liquid working medium 20, and introduces only the gaseous working medium 20 from the suction pipe 401 into the inside of the sealed container 40.

[0029] The control device 3 in FIGS. 2 and 3 includes a drive circuit 31, a detection circuit 32, and a control circuit 33.

[0030] The drive circuit 31 drives the electric motor 42. The drive circuit 31 in FIG. 2 supplies drive power to the electric motor 42 based on power from the power supply 10. In this embodiment, the power supply 10 is an AC power supply. The drive circuit 31 supplies drive power to the electric motor 42 based on the AC power from the power supply 10. In particular, the drive circuit 31 supplies three-phase AC power as drive power to the electric motor 42. The drive circuit 31 includes a converter circuit 311 and an inverter circuit 312.

[0031] The converter circuit 311 converts AC power from the power supply 10 into DC power. The converter circuit 311 includes a rectifier circuit 311a and a smoothing circuit 311b. The rectifier circuit 311a is a diode bridge composed of multiple diodes D1 to D4. The power supply 10 is connected between the input terminals of the rectifier circuit 311a (the connection point between diodes D1 and D2 and the connection point between diodes D3 and D4), and the smoothing circuit 311b is connected between the output terminals of the rectifier circuit 311a (the connection point between diodes D1 and D3 and the connection point between diodes D2 and D4). The smoothing circuit 311b includes a series circuit of an inductor L1 and a capacitor C1, smoothes the voltage between the output terminals of the rectifier circuit 311a, and outputs the voltage across the capacitor C1. The configurations of the rectifier circuit 311a and the smoothing circuit 311b in FIG. 2 are well known, so detailed description thereof will be omitted.

[0032] The inverter circuit 312 supplies three-phase AC power to the electric motor 42 based on the DC power from the converter circuit 311. In particular, the inverter circuit 312 in FIG. 2 supplies three-phase AC power to the electric motor 42. The inverter circuit 312 includes a plurality of semiconductor switching elements U1, U2, V1, V2, W1, and W2. The semiconductor switching elements U1, U2, V1, V2, W1, and W2 are, for example, transistors.

[0033] The semiconductor switching elements U1 and U2 in Fig. 2 form a series circuit. The series circuit of the semiconductor switching elements U1 and U2 is connected in parallel to the capacitor C1 of the converter circuit 311. The connection point of the semiconductor switching elements U1 and U2 is connected to the electric motor 42 via a U-phase power supply line Pu. As shown in Fig. 3, the power supply line Pu is connected to one end (U-phase input terminal) of the U-phase winding Lu of the electric motor 42.

[0034] The semiconductor switching elements V1 and V2 in Fig. 2 form a series circuit. The series circuit of the semiconductor switching elements V1 and V2 is connected in parallel to the capacitor C1 of the converter circuit 311. The connection point of the semiconductor switching elements V1 and V2 is connected to the motor 42 via a V-phase power supply line Pv. As shown in Fig. 3, the power supply line Pv is connected to one end (V-phase input terminal) of the V-phase winding Lv of the motor 42.

[0035] The semiconductor switching elements W1 and W2 in Fig. 2 form a series circuit. The series circuit of the semiconductor switching elements W1 and W2 is connected in parallel to the capacitor C1 of the converter circuit 311. The connection point of the semiconductor switching elements W1 and W2 is connected to the motor 42 via a W-phase power supply line Pw. As shown in Fig. 3, the power supply line Pw is connected to one end (W-phase input terminal) of the W-phase winding Lw of the motor 42.

[0036] In the inverter circuit 312, the series circuit of semiconductor switching elements U1 and U2 constitutes a U-phase leg. The series circuit of semiconductor switching elements V1 and V2 constitutes a V-phase leg. The series circuit of semiconductor switching elements W1 and W2 constitutes a W-phase leg. In this case, the semiconductor switching elements U1, U2, V1, V2, W1, and W2 are also called arms.

[0037] The configuration of the inverter circuit 312 in FIG. 2 is well known, and therefore a detailed description thereof will be omitted.

[0038] The detection circuit 32 detects insulation deterioration of the windings of the electric motor 42 (U-phase winding Lu, V-phase winding Lv, and W-phase winding Lw).

[0039] In this embodiment, the detection circuit 32 detects insulation deterioration of the windings (U-phase winding Lu, V-phase winding Lv, and W-phase winding Lw) of the motor 42 based on evaluation values ​​of the impulse responses of the windings Lu, Lv, and Lw of the motor 42. More specifically, the detection circuit 32 measures the impulse responses of the windings Lu, Lv, and Lw of the motor 42. As an example, the impulse responses are given as changes over time in the current or voltage of the windings Lu, Lv, and Lw that occur when an impulse voltage is applied to the windings Lu, Lv, and Lw of the motor 42.

[0040] The detection circuit 32 in Figure 3 measures the impulse responses of the windings Lu, Lv, and Lw of the motor 42 using power supply lines Pu, Pv, and Pw that run from the drive circuit 31 to the windings Lu, Lv, and Lw of the motor 42. The detection circuit 32 in Figure 3 can apply an impulse voltage to the windings Lu, Lv, and Lw of the motor 42 via the power supply lines Pu and Pv. The detection circuit 32 in Figure 3 can apply an impulse voltage to the windings Lv and Lw of the motor 42 via the power supply lines Pv and Pw. The detection circuit 32 in Figure 3 can apply an impulse voltage to the windings Lw and Lu of the motor 42 via the power supply lines Pw and Pu.

[0041] The detection circuit 32 detects insulation degradation of the windings Lu, Lv, and Lw of the electric motor 42 based on a comparison with the evaluation values ​​of the impulse responses of the windings Lu, Lv, and Lw of the electric motor 42 obtained by measurement. Examples of the evaluation value of the impulse response include the area (integral value) of the impulse response or a numerical value indicating the waveform of the impulse response. The detection circuit 32 may determine that insulation degradation has occurred in the windings Lu, Lv, and Lw of the electric motor 42 when the evaluation value of the impulse response of the windings Lu, Lv, and Lw of the electric motor 42 is equal to or less than a threshold. The threshold may be set so as to determine insulation degradation of the windings Lu, Lv, and Lw based on the evaluation values ​​of the windings Lu, Lv, and Lw in a normal state and the evaluation values ​​in a deteriorated state. The measurement of the impulse responses of the windings Lu, Lv, and Lw of the electric motor 42 may be actual values ​​obtained by direct measurement or estimated values ​​obtained by indirect measurement.

[0042] The control circuit 33 may be realized, for example, by a computer system including at least one processor (microprocessor) and one or more memories. The control circuit 33 controls the drive circuit 31. More specifically, the control circuit 33 controls the switching of multiple semiconductor switching elements U1, U2, V1, V2, W1, and W2 of the inverter circuit 312 of the drive circuit 31 so that the inverter circuit 312 supplies three-phase AC power to the motor 42 based on the DC power from the smoothing circuit 311b. In this embodiment, the control circuit 33 also controls the aperture of the expansion valve 6, the rotation speed of the fan of the first blower 5a, the rotation speed of the fan of the second blower 7a, and the switching of the four-way valve 8.

[0043] The control circuit 33 has the function of performing cooling operation and heating operation. In cooling operation, the control circuit 33 controls the refrigeration cycle circuit 2 so that the first heat exchanger 5 functions as a condenser and the second heat exchanger 7 functions as an evaporator. In heating operation, the control circuit 33 controls the refrigeration cycle circuit 2 so that the first heat exchanger 5 functions as an evaporator and the second heat exchanger 7 functions as a condenser.

[0044] The control circuit 33 has a plurality of control modes for each of the cooling operation and the heating operation. In this embodiment, the control circuit 33 has a first control mode and a second control mode. The first control mode is a normal operation mode in which the refrigeration cycle circuit 2 is controlled so that the current temperature of the space that is the target of temperature management by the refrigeration cycle device 1 coincides with a target temperature. The second control mode is a safe operation mode or a restricted operation mode in which the refrigeration cycle circuit 2 is controlled so that the disproportionation reaction of the working fluid does not proceed in the refrigeration cycle circuit 2.

[0045] The causes of the disproportionation reaction of the working fluid are thought to be heat and radicals. For example, when radicals are generated under high temperature and pressure, the disproportionation reaction of the working fluid is thought to proceed. Radicals may be generated, for example, by a discharge phenomenon in the compressor 4. The discharge phenomenon in the compressor 4 may be caused by insulation deterioration of the windings Lu, Lv, and Lw of the electric motor 42. The insulation deterioration of the windings Lu, Lv, and Lw of the electric motor 42 may ultimately lead to insulation breakdown of the electric motor 42. In the compressor 4, heat is generated in the electric motor 42 when it is driven, so heat dissipation from the electric motor 42 is necessary. Using the working fluid is very efficient for heat dissipation from the electric motor 42. From this perspective, the electric motor 42 is disposed in the sealed container 40 so that it can come into contact with the working fluid. However, if insulation breakdown occurs in the electric motor 42 and a discharge phenomenon occurs, the discharge phenomenon directly affects the working fluid, resulting in the generation of radicals under high temperature and pressure. In this way, the occurrence of insulation deterioration in the windings Lu, Lv, and Lw of the electric motor 42 is highly likely to promote the progress of the disproportionation reaction of the working medium.

[0046] In this embodiment, the control circuit 33 executes the first control mode when the detection circuit 32 does not detect insulation deterioration in the windings Lu, Lv, Lw of the electric motor 42. The control circuit 33 executes the second control mode when the detection circuit 32 detects insulation deterioration in the windings Lu, Lv, Lw of the electric motor 42.

[0047] The first control mode and the second control mode will be described in more detail below.

[0048] As described above, the first control mode is a normal operation mode in which the refrigeration cycle circuit 2 is controlled so that the current temperature of the space subject to temperature management by the refrigeration cycle apparatus 1 coincides with the target temperature. In the present embodiment, the first control mode controls the refrigeration cycle circuit 2 under a first condition. The first condition includes controlling the drive circuit 31 so that the current temperature of the space subject to temperature management by the refrigeration cycle apparatus 1 coincides with the target temperature. As an optional element, the first condition may include controlling the expansion valve 6, the first blower 5a, the second blower 7a, and the four-way valve 8 so that the current temperature of the space subject to temperature management by the refrigeration cycle apparatus 1 coincides with the target temperature. In the first control mode, the control circuit 33 controls the target value of the frequency of the three-phase AC power output by the drive circuit 31 to the motor 42 of the compressor 4, the target value of the aperture of the expansion valve 6, the target value of the fan speed of the first blower 5a, the target value of the fan speed of the second blower 7a, and the switching state of the four-way valve 8. In the first control mode, the target value of the frequency of the three-phase AC power, the target value of the opening of the expansion valve 6, the target value of the fan rotation speed of the first blower 5a, and the target value of the fan rotation speed of the second blower 7a can be set based on the current temperature and the target temperature of the space that is the target of temperature management by the refrigeration cycle apparatus 1. The switching state of the four-way valve 8 can be determined according to, for example, cooling operation, heating operation, or dehumidifying operation.

[0049] As described above, the second control mode is a safe operation mode or a restricted operation mode in which the refrigeration cycle circuit 2 is controlled to prevent the disproportionation reaction of the working fluid in the refrigeration cycle circuit 2 from progressing. In the present embodiment, the second control mode controls the refrigeration cycle circuit 2 under the second condition. The second condition is a condition in which at least one of the maximum pressure and the maximum temperature of the working fluid 20 in the compressor 4 is lower than that under the first condition. That is, the second condition is set so that the high-temperature, high-pressure environment in which the working fluid 20 is placed is more alleviated than that under the first condition. The second condition includes controlling the drive circuit 31 so that at least one of the maximum pressure and the maximum temperature of the working fluid in the compressor 4 is lower than that under the first condition. As an optional element, the second condition may include controlling the expansion valve 6, the first blower 5a, the second blower 7a, and the four-way valve 8 so that at least one of the maximum pressure and the maximum temperature of the working fluid in the compressor 4 is lower than that under the first condition. It is believed that when radicals are generated under high temperature and high pressure, the disproportionation reaction of the working fluid proceeds, so in the second control mode, the refrigeration cycle circuit 2 is controlled so that the conditions of high temperature and high pressure do not occur.

[0050] In the refrigeration cycle circuit 2, the pressure and temperature of the working medium in the compressor 4 tend to increase as the operating load increases. For example, in cooling operation, the higher the outdoor air temperature, the higher the operating load. For example, in heating operation, the lower the outdoor air temperature, the higher the operating load. An increase in operating load contributes to an increase in the maximum pressure or maximum temperature of the working medium 20 in the compressor 4. The second control mode stops operation of the motor 42 by the drive circuit 31 to prevent a situation in which, due to an increase in operating load, the pressure of the working medium 20 in the compressor 4 reaches a pressure that could cause a disproportionation reaction of the working medium 20 to proceed if a discharge phenomenon occurs in the windings Lu, Lv, and Lw of the motor 42 within the sealed container 40, or the temperature of the working medium 20 in the compressor 4 reaches a temperature that could cause a disproportionation reaction of the working medium 20 to proceed if a discharge phenomenon occurs in the windings Lu, Lv, and Lw of the motor 42 within the sealed container 40. In the present embodiment, the second control mode stops the operation of the motor 42 by the drive circuit 31 when the outside air temperature exceeds the upper limit operation temperature during cooling operation. In the present embodiment, the second control mode stops the operation of the motor 42 by the drive circuit 31 when the outside air temperature falls below the lower limit operation temperature during heating operation. The upper limit operation temperature can be appropriately set based on whether, during cooling operation, the pressure of the working medium 20 in the compressor 4 reaches a pressure that may cause a disproportionation reaction of the working medium 20 to proceed if a discharge phenomenon occurs in the windings Lu, Lv, Lw of the motor 42 within the sealed container 40, and whether the temperature of the working medium 20 in the compressor 4 reaches a temperature that may cause a disproportionation reaction of the working medium 20 to proceed if a discharge phenomenon occurs in the windings Lu, Lv, Lw of the motor 42 within the sealed container 40. The lower limit operating temperature can be appropriately set based on whether, during heating operation, the pressure of the working medium 20 in the compressor 4 reaches a pressure that may cause a disproportionation reaction of the working medium 20 to proceed if a discharge phenomenon occurs in the windings Lu, Lv, Lw of the electric motor 42 within the sealed container 40, and whether the temperature of the working medium 20 in the compressor 4 reaches a temperature that may cause a disproportionation reaction of the working medium 20 to proceed if a discharge phenomenon occurs in the windings Lu, Lv, Lw of the electric motor 42 within the sealed container 40.Thus, under the second condition, the refrigeration cycle circuit 2 is not operated under an operating load that may cause a disproportionation reaction of the working medium 20 to proceed if a discharge occurs in the windings Lu, Lv, and Lw of the electric motor 42 within the sealed container 40. This is equivalent to setting upper limits on the pressure and temperature of the working medium 20 in the compressor 4. In other words, under the second condition, at least one of the maximum pressure and maximum temperature of the working medium in the compressor 4 is lower than under the first condition. This improves the safety of the operation of the refrigeration cycle apparatus 1. Furthermore, the second control mode stops the operation of the first blower 5a and the second blower 7a. In the second control mode, the switching state of the four-way valve 8 is not particularly changed and may remain in the immediately preceding state.

[0051] [1.2 Operation] An example of the operation of the control circuit 33 of the control device 3 of the refrigeration cycle apparatus 1 will be briefly described below with reference to Fig. 4. Fig. 4 is a flowchart of an example of the operation of the control circuit 33 of the control device 3.

[0052] Before driving the electric motor 42 by the drive circuit 31, the control circuit 33 causes the detection circuit 32 to execute a process for detecting insulation deterioration of the windings Lu, Lv, Lw of the electric motor 42 (S11).

[0053] If the detection circuit 32 does not detect insulation deterioration of the windings Lu, Lv, Lw of the electric motor 42 (S12; NO), the control circuit 33 executes the first control mode and controls the refrigeration cycle circuit 2 under the first condition (S13).

[0054] If the detection circuit 32 detects insulation deterioration of the windings Lu, Lv, Lw of the electric motor 42 (S12; YES), the control circuit 33 executes the second control mode and controls the refrigeration cycle circuit 2 under the second condition (S14).

[0055] In this way, before driving the electric motor 42 by the drive circuit 31, the control circuit 33 determines whether the detection circuit 32 has detected insulation degradation in the windings Lu, Lv, and Lw of the electric motor 42. The control circuit 33 executes the first control mode when the detection circuit 32 has not detected insulation degradation in the windings Lu, Lv, and Lw of the electric motor 42. The control circuit 33 executes the second control mode when the detection circuit 32 has detected insulation degradation in the windings Lu, Lv, and Lw of the electric motor 42. Therefore, when insulation degradation has occurred in the windings Lu, Lv, and Lw of the electric motor 42 and there is a possibility that a disproportionation reaction of the working medium will progress, the normal operation mode is switched to the safe operation mode, thereby suppressing the disproportionation reaction of the working medium.

[0056] [1.3 Effects, etc.] The refrigeration cycle device 1 described above includes a refrigeration cycle circuit 2 including a compressor 4, a condenser (first heat exchanger 5, second heat exchanger 7), an expansion valve 6, and an evaporator (first heat exchanger 5, second heat exchanger 7) and through which a working medium 20 circulates, and a control device 3 that controls the compressor 4 of the refrigeration cycle circuit 2. The working medium 20 contains an ethylene-based fluoroolefin as a refrigerant component. The compressor 4 includes a sealed container 40 that forms a flow path for the working medium 20, a compression mechanism 41 located within the sealed container 40 and that compresses the working medium 20, and an electric motor 42 located within the sealed container 40 and that operates the compression mechanism 41. The control device 3 includes a drive circuit 31 that drives the electric motor 42, a detection circuit 32 that detects insulation deterioration of the windings Lu, Lv, and Lw of the electric motor 42, and a control circuit 33 that has a first control mode that controls the drive circuit 31 under a first condition and a second control mode that controls the drive circuit 31 under a second condition where at least one of the maximum pressure and the maximum temperature of the working medium 20 in the compressor 4 is lower than the first condition, and that selects the second control mode when the detection circuit 32 detects insulation deterioration of the windings Lu, Lv, and Lw of the electric motor 42. This configuration makes it possible to suppress the disproportionation reaction of the working medium 20.

[0057] In the refrigeration cycle apparatus 1, before the drive circuit 31 drives the electric motor 42, the control circuit 33 determines whether the detection circuit 32 has detected insulation deterioration in the windings Lu, Lv, and Lw of the electric motor 42. The control circuit 33 executes the first control mode when the detection circuit 32 has not detected insulation deterioration in the windings Lu, Lv, and Lw of the electric motor 42, and executes the second control mode when the detection circuit 32 has detected insulation deterioration in the windings Lu, Lv, and Lw of the electric motor 42. This configuration can improve the safety of the operation of the refrigeration cycle apparatus 1.

[0058] In the refrigeration cycle apparatus 1, the refrigeration cycle circuit 2 includes a first heat exchanger 5 that exchanges heat between outside air and the working medium 20 and a second heat exchanger 7 that exchanges heat between indoor air and the working medium 20. The control circuit 33 has a function of executing a cooling operation in which the refrigeration cycle circuit 2 is controlled so that the first heat exchanger 5 functions as a condenser and the second heat exchanger 7 functions as an evaporator, and a heating operation in which the refrigeration cycle circuit 2 is controlled so that the first heat exchanger 5 functions as an evaporator and the second heat exchanger 7 functions as a condenser. In the second control mode, the drive circuit 31 stops operation of the electric motor 42 when the outside air temperature exceeds an upper limit temperature during the cooling operation, or stops operation of the electric motor 42 when the outside air temperature falls below a lower limit temperature during the heating operation. This configuration can improve the safety of the operation of the refrigeration cycle apparatus 1.

[0059] In the refrigeration cycle apparatus 1, the detection circuit 32 measures at least one of the impulse response, resistance, and inductance of the windings Lu, Lv, and Lw of the electric motor 42, and detects insulation deterioration of the windings Lu, Lv, and Lw of the electric motor 42 based on at least one of comparing at least one of the impulse response, resistance, and inductance of the windings Lu, Lv, and Lw of the electric motor 42 with a threshold value and comparing at least one of the impulse response, resistance, and inductance of the multiple windings Lu, Lv, and Lw of the electric motor 42 with each other. This configuration enables improved accuracy in detecting insulation deterioration of the windings Lu, Lv, and Lw of the electric motor 42.

[0060] In the refrigeration cycle apparatus 1, the detection circuit 32 measures at least one of the impulse response, resistance value, and inductance of the windings Lu, Lv, and Lw of the electric motor 42 by utilizing the power supply lines Pu, Pv, and Pw extending from the drive circuit 31 to the windings Lu, Lv, and Lw of the electric motor 42. This configuration enables the configuration of the control circuit to be simplified.

[0061] In the refrigeration cycle apparatus 1, the detection circuit 32 is arranged on the same board 34 as the control circuit 33. This configuration allows the configuration of the control device 3 to be simplified.

[0062] In the refrigeration cycle device 1, the ethylene-based fluoroolefin includes an ethylene-based fluoroolefin that undergoes a disproportionation reaction. This configuration makes it possible to suppress the disproportionation reaction of the working fluid 20.

[0063] In the refrigeration cycle device 1, the ethylene-based fluoroolefin is 1,1,2-trifluoroethylene, trans-1,2-difluoroethylene, cis-1,2-difluoroethylene, 1,1-difluoroethylene, tetrafluoroethylene, or monofluoroethylene. This configuration makes it possible to suppress the disproportionation reaction of the working fluid 20.

[0064] In the refrigeration cycle device 1, the working fluid 20 further contains difluoromethane as a refrigerant component. This configuration makes it possible to suppress the disproportionation reaction of the working fluid 20.

[0065] In the refrigeration cycle apparatus 1, the working fluid 20 further contains saturated hydrocarbons. This configuration makes it possible to suppress the disproportionation reaction of the working fluid 20.

[0066] In the refrigeration cycle device 1, the working fluid 20 contains a haloalkane having 1 or 2 carbon atoms as a disproportionation inhibitor that suppresses the disproportionation reaction of ethylene-based fluoroolefins. This configuration makes it possible to suppress the disproportionation reaction of the working fluid 20.

[0067] In the refrigeration cycle device 1, the saturated hydrocarbons include n-propane. This configuration makes it possible to suppress the disproportionation reaction of the working medium 20.

[0068] [2. Modifications] The embodiments of the present disclosure are not limited to the above-described embodiments. The above-described embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the above-described embodiments are listed below. The modifications described below can be applied in appropriate combinations.

[0069] [2.1 Modification 1] Fig. 5 is a schematic diagram of a configuration example of the compressor 4 and control device 3A of a refrigeration cycle device of Modification 1. The control device 3A of Fig. 5 includes a drive circuit 31, a detection circuit 32, and a control circuit 33. In the control device 3A of Fig. 5, the detection circuit 32 and the control circuit 33 form an integrated circuit 35. In other words, the detection circuit 32 and the control circuit 33 are not separate circuit components but are integrated as a single circuit component. This reduces the space required to arrange the detection circuit 32 and the control circuit 33, thereby simplifying the configuration of the control device 3A. The integrated circuit 35 may be arranged on the same board as the drive circuit 31.

[0070] As described above, in the control device 3A of the refrigeration cycle device, the detection circuit 32 and the control circuit 33 constitute the integrated circuit 35. This configuration makes it possible to simplify the configuration of the control device 3A.

[0071] [2.2 Modification 2] FIG. 6 is a schematic diagram of a configuration example of the compressor 4 and the control device 3B of a refrigeration cycle device according to Modification 2.

[0072] The control device 3B in FIG. 6 includes a drive circuit 31, a detection circuit 32, a control circuit 33, a pressure measurement circuit 36, and a temperature measurement circuit 37.

[0073] The pressure measurement circuit 36 ​​measures the pressure of the working medium 20 in the compressor 4. The pressure measurement circuit 36 ​​in FIG. 6 measures the internal pressure of the sealed container 40 of the compressor 4 as the pressure of the working medium 20 in the compressor 4. The pressure measurement circuit 36 ​​outputs a pressure measurement signal indicating the measured internal pressure (the pressure of the working medium 20 in the compressor 4) to the control circuit 33. The pressure measurement circuit 36 ​​is, for example, a pressure sensor located in the sealed container 40. The pressure measurement circuit 36 ​​is not limited to a pressure sensor located in the sealed container 40. The pressure measurement circuit 36 ​​may be any circuit as long as it can directly or indirectly measure the pressure of the working medium 20 in the compressor 4.

[0074] The temperature measurement circuit 37 measures the temperature of the working medium 20 in the compressor 4. The temperature measurement circuit 37 in FIG. 6 measures the internal temperature of the sealed container 40 of the compressor 4 as the temperature of the working medium 20 in the compressor 4. The temperature measurement circuit 37 outputs a temperature measurement signal indicating the measured internal temperature (the temperature of the working medium 20 in the compressor 4) to the control circuit 33. The temperature measurement circuit 37 is, for example, a temperature sensor located inside the sealed container 40. The temperature measurement circuit 37 is not limited to a temperature sensor located inside the sealed container 40. The temperature measurement circuit 37 may be any circuit as long as it can directly or indirectly measure the temperature of the working medium 20 in the compressor 4.

[0075] In this modification, the control circuit 33 also executes the first control mode when the detection circuit 32 does not detect insulation deterioration in the windings Lu, Lv, Lw of the electric motor 42. The control circuit 33 executes the second control mode when the detection circuit 32 detects insulation deterioration in the windings Lu, Lv, Lw of the electric motor 42.

[0076] Similar to the second control mode of the embodiment, the second control mode of this modification is a safe operation mode or a restricted operation mode in which the refrigeration cycle circuit 2 is controlled so as to prevent the disproportionation reaction of the working medium 20 from progressing in the refrigeration cycle circuit 2. In this modification, the second control mode controls the refrigeration cycle circuit 2 so that the pressure of the working medium 20 in the compressor 4 is equal to or lower than a predetermined pressure and the temperature of the working medium 20 in the compressor 4 is equal to or lower than a predetermined temperature. Specifically, in the second control mode, the control circuit 33 can set a target value for the frequency of the three-phase AC power output by the drive circuit 31 to the motor 42 of the compressor 4, a target value for the aperture of the expansion valve 6, a target value for the rotation speed of the fan of the first blower 5a, and a target value for the rotation speed of the fan of the second blower 7a, so that the pressure of the working medium 20 in the compressor 4 measured by the pressure measurement circuit 36 ​​is equal to or lower than the predetermined pressure and the temperature of the working medium 20 in the compressor 4 measured by the temperature measurement circuit 37 is equal to or lower than the predetermined temperature. The switching state of the four-way valve 8 can be determined depending on, for example, the cooling operation, the heating operation, or the dehumidifying operation.

[0077] The predetermined pressure and the predetermined temperature are set so that the possibility of the disproportionation reaction of the working medium 20 progressing is lower than when the control of the refrigeration cycle circuit 2 is continued in the first control mode. In this modification, the predetermined pressure and the predetermined temperature are set so that the disproportionation reaction of the working medium 20 does not progress even when a discharge phenomenon occurs in the windings Lu, Lv, and Lw of the electric motor 42 in the sealed container 40. The predetermined pressure and the predetermined temperature may be set appropriately depending on the composition of the working medium 20, etc. For example, the predetermined pressure and the predetermined temperature may be set based on the results of a test to determine whether the disproportionation reaction of the working medium 20 progresses in a state in which a discharge phenomenon occurs in the windings Lu, Lv, and Lw of the electric motor 42 in the sealed container 40.

[0078] The predetermined pressure can be set based on the pressure of the working medium 20 in the normal operation range of the refrigeration cycle circuit 2. As an example, when the pressure of the working medium 20 in the normal operation range of the refrigeration cycle circuit 2 is 6 MPa, the predetermined pressure is set to 5 MPa.

[0079] The predetermined temperature is, for example, lower than the safe temperature of the working medium 20 and lower than the heat resistance temperature of the insulating members of the electric motor 42 of the compressor 4. The safe temperature of the working medium 20 can be set based on the temperature at which a disproportionation reaction of the working medium 20 may occur under the pressure conditions during normal operation of the refrigeration cycle apparatus 1. As an example, the safe temperature of the working medium 20 is set to 150°C. The heat resistance temperature of the electric motor 42 of the compressor 4 is set based on the heat resistance temperature of the insulating members of the electric motor 42 of the compressor 4. For example, the heat resistance temperature of the insulating members of the electric motor 42 may be the heat resistance temperature of the insulating member with the lowest heat resistance temperature among the insulating members of the electric motor 42. If the refrigeration cycle apparatus 1 continues to operate with the internal temperature exceeding the heat resistance temperature, the insulating paper may be destroyed, increasing the possibility of a discharge occurring. As an example, the insulating member with the lowest heat resistance temperature in the electric motor 42 may be the insulating paper between the stator core (e.g., electromagnetic steel sheet) and the stator winding (e.g., magnet wire). For example, if the heat resistance class of the insulating paper is Class E as defined in JIS C 4003, the heat resistance temperature is 120°C. If the safe temperature of the working fluid 20 is 150°C and the heat resistance temperature of the electric motor 42 of the compressor 4 is 120°C, the predetermined temperature is set to a temperature lower than 120°C. In this case, taking into account the time difference in temperature detection between the temperature of the working fluid and the stator, heat dissipation, etc., a safety margin of, for example, about 5°C may be set. Therefore, the predetermined temperature may be set to 115°C. The safety margin depends on the distance between the temperature measurement circuit 37 and the stator or the motor efficiency, so it is not limited to 5°C and may be a value between 0 and 20°C. The heat resistance class of the insulating paper is not limited to Class E, and may be Class B, Class F, etc. If the heat resistance class is Class B, the heat resistance temperature is 130°C. If the safe temperature of the working fluid 20 is 150°C, the predetermined temperature is set to a temperature lower than 130°C, for example, 125°C. If the heat resistance class is Class F, the heat resistance temperature is 155° C. If the safe temperature of the working medium 20 is 150° C., the predetermined temperature is set to a temperature lower than 150° C., for example, 145° C.

[0080] In the control device 3B of the refrigeration cycle device described above, the second control mode controls the refrigeration cycle circuit 2 so that the pressure of the working medium 20 in the compressor 4 is equal to or lower than a predetermined pressure and the temperature of the working medium 20 in the compressor 4 is equal to or lower than a predetermined temperature. The predetermined pressure and predetermined temperature are set so that the disproportionation reaction of the working medium 20 does not proceed even if a discharge phenomenon occurs in the windings Lu, Lv, Lw of the electric motor 42 inside the sealed container 40. This configuration enables the refrigeration cycle device to continue operating while suppressing the disproportionation reaction of the working medium 20.

[0081] [2.3 Other Modifications] In one modification, in addition to or instead of comparing the evaluation values ​​of the impulse responses of the windings Lu, Lv, and Lw of the motor 42 with the threshold value, the detection circuit 32 may detect insulation degradation of the windings Lu, Lv, and Lw of the motor 42 based on a comparison of the evaluation values ​​of the impulse responses of the multiple windings Lu, Lv, and Lw of the motor 42. The evaluation values ​​of the impulse responses of the multiple windings Lu, Lv, and Lw of the motor 42 are usually the same. Therefore, when the difference between the evaluation values ​​of the impulse responses of any combination of the multiple windings Lu, Lv, and Lw of the motor 42 is equal to or greater than a predetermined value, the detection circuit 32 may determine that insulation degradation has occurred in one of the windings Lu, Lv, and Lw of the motor 42.

[0082] In one modified example, the detection circuit 32 may detect insulation degradation of the windings (U-phase winding Lu, V-phase winding Lv, and W-phase winding Lw) of the motor 42 based on the resistance values ​​of the windings Lu, Lv, and Lw of the motor 42, rather than on the impulse response. As an example, the detection circuit 32 measures the resistance values ​​of the windings Lu, Lv, and Lw of the motor 42 and detects insulation degradation of the windings Lu, Lv, and Lw of the motor 42 based on a comparison of the resistance values ​​of the windings Lu, Lv, and Lw of the motor 42 with a threshold value. Since the measurement of the resistance values ​​of the windings Lu, Lv, and Lw of the motor 42 itself can be achieved by a conventionally known method, a description thereof will be omitted. The detection circuit 32 may determine that insulation degradation has occurred in the windings Lu, Lv, and Lw of the motor 42 when the resistance values ​​of the windings Lu, Lv, and Lw of the motor 42 are equal to or less than the threshold value. The threshold value may be set so as to determine insulation degradation of the windings Lu, Lv, Lw based on the resistance values ​​of the windings Lu, Lv, Lw in a normal state and the resistance values ​​of the windings when their insulation has deteriorated. Because the resistance values ​​of the windings Lu, Lv, Lw may vary depending on the temperatures of the windings Lu, Lv, Lw, the threshold value may be a function of the temperatures of the windings Lu, Lv, Lw. The resistance values ​​of the windings Lu, Lv, Lw of the electric motor 42 may be measured directly as actual values ​​or indirectly as estimated values.

[0083] In one modified example, in addition to or instead of comparing the resistance values ​​of the windings Lu, Lv, and Lw of the motor 42 with a threshold value, the detection circuit 32 may detect insulation degradation of the windings Lu, Lv, and Lw of the motor 42 based on a comparison of the resistance values ​​of the multiple windings Lu, Lv, and Lw of the motor 42. The resistance values ​​of the multiple windings Lu, Lv, and Lw of the motor 42 are normally the same. Therefore, the detection circuit 32 may determine that insulation degradation has occurred in one of the windings Lu, Lv, and Lw of the motor 42 when the difference in resistance values ​​between any combination of the multiple windings Lu, Lv, and Lw of the motor 42 is equal to or greater than a predetermined value.

[0084] In one modified example, the detection circuit 32 may measure the resistance values ​​of the windings Lu, Lv, and Lw of the motor 42 using power supply lines Pu, Pv, and Pw that run from the drive circuit 31 to the windings Lu, Lv, and Lw of the motor 42. As shown in FIG. 3 , the detection circuit 32 may measure the resistance value of the series circuit of the windings Lu, Lv of the motor 42 via the power supply lines Pu, Pv. The detection circuit 32 may measure the resistance value of the series circuit of the windings Lv, Lw of the motor 42 via the power supply lines Pv, Pw. The detection circuit 32 may measure the resistance value of the series circuit of the windings Lw, Lu of the motor 42 via the power supply lines Pw, Pu. The resistance values ​​of the windings Lu, Lv, and Lw are obtained by calculation.

[0085] In one modified example, the detection circuit 32 may detect insulation degradation of the windings (U-phase winding Lu, V-phase winding Lv, and W-phase winding Lw) of the motor 42 based on the inductance of the windings Lu, Lv, and Lw of the motor 42, rather than on the impulse response or resistance value. As an example, the detection circuit 32 measures the inductance of the windings Lu, Lv, and Lw of the motor 42 and detects insulation degradation of the windings Lu, Lv, and Lw of the motor 42 based on a comparison of the inductance of the windings Lu, Lv, and Lw of the motor 42 with a threshold value. Since the measurement of the inductance of the windings Lu, Lv, and Lw of the motor 42 can be achieved by a conventionally known method, a description thereof will be omitted. The detection circuit 32 may determine that insulation degradation has occurred in the windings Lu, Lv, and Lw of the motor 42 when the inductance of the windings Lu, Lv, and Lw of the motor 42 is equal to or less than the threshold value. The threshold value can be set so as to determine insulation deterioration of the windings Lu, Lv, Lw based on the inductance of the windings Lu, Lv, Lw in a normal state and the inductance of the windings Lu, Lv, Lw in a state of insulation deterioration. The inductance of the windings Lu, Lv, Lw of the electric motor 42 may be measured as an actual value by direct measurement or as an estimated value by indirect measurement.

[0086] In one modified example, in addition to or instead of comparing the inductance of the windings Lu, Lv, and Lw of the motor 42 with the threshold value, the detection circuit 32 may detect insulation degradation of the windings Lu, Lv, and Lw of the motor 42 based on a comparison of the inductances of the multiple windings Lu, Lv, and Lw of the motor 42. The inductances of the multiple windings Lu, Lv, and Lw of the motor 42 usually have the same value. Therefore, when the difference in inductance between any combination of the multiple windings Lu, Lv, and Lw of the motor 42 is equal to or greater than a predetermined value, the detection circuit 32 may determine that insulation degradation has occurred in one of the windings Lu, Lv, and Lw of the motor 42.

[0087] In one modified example, the detection circuit 32 may measure the inductance of the windings Lu, Lv, and Lw of the motor 42 using power supply lines Pu, Pv, and Pw that run from the drive circuit 31 to the windings Lu, Lv, and Lw of the motor 42. As shown in FIG. 3 , the detection circuit 32 may measure the inductance of the series circuit of the windings Lu and Lv of the motor 42 via the power supply lines Pu and Pv. The detection circuit 32 may measure the inductance of the series circuit of the windings Lv and Lw of the motor 42 via the power supply lines Pv and Pw. The detection circuit 32 may measure the inductance of the series circuit of the windings Lw and Lu of the motor 42 via the power supply lines Pw and Pu. The inductance of each winding Lu, Lv, and Lw is obtained by calculation.

[0088] In one modification, the detection circuit 32 may detect insulation deterioration of the windings Lu, Lv, Lw of the motor 42 using two or more of the impulse response, resistance, and inductance of the windings Lu, Lv, Lw of the motor 42. This makes it possible to detect insulation deterioration of the windings Lu, Lv, Lw of the motor 42 from multiple perspectives, thereby improving the accuracy of detecting insulation deterioration of the windings Lu, Lv, Lw of the motor 42.

[0089] In this way, the detection circuit 32 may measure at least one of the impulse response, resistance, and inductance of the windings Lu, Lv, and Lw of the electric motor 42, and detect insulation deterioration of the windings Lu, Lv, and Lw of the electric motor 42 based on at least one of comparing the evaluation value of the impulse response, the resistance, and the inductance of the windings Lu, Lv, and Lw of the electric motor 42 with a threshold value and comparing the evaluation value of the impulse response, the resistance, and the inductance of the plurality of windings Lu, Lv, and Lw of the electric motor 42 with each other. In this case, the detection circuit 32 may measure at least one of the impulse response, the resistance, and the inductance of the windings Lu, Lv, and Lw of the electric motor 42 using the power supply lines Pu, Pv, and Pw that run from the drive circuit 31 to the windings Lu, Lv, and Lw of the electric motor 42.

[0090] In one modification, the impulse voltage may be applied to the motor 42 using the drive circuit 31. By briefly turning on the semiconductor switching elements U1 and V2 from an off state, the impulse voltage can be applied to the windings Lu and Lv of the motor 42 via the power feed lines Pu and Pv. By briefly turning on the semiconductor switching elements V1 and W2 from an off state, the impulse voltage can be applied to the windings Lv and Lw of the motor 42 via the power feed lines Pv and Pw. By briefly turning on the semiconductor switching elements W1 and U2 from an off state, the impulse voltage can be applied to the windings Lw and Lu of the motor 42 via the power feed lines Pw and Pu.

[0091] In one modified example, the second control mode may have at least one of a function of stopping the operation of the motor 42 by the drive circuit 31 when the outside air temperature exceeds an upper limit operation temperature during cooling operation and a function of stopping the operation of the motor 42 by the drive circuit 31 when the outside air temperature falls below a lower limit operation temperature during heating operation. The second control mode may stop the operation of the motor 42 by the drive circuit 31 regardless of the outside air temperature. In other words, when the detection circuit 32 detects insulation deterioration of the windings Lu, Lv, and Lw of the motor 42, the control circuit 33 may stop the operation of the motor 42 by the drive circuit 31.

[0092] In one modified example, the refrigeration cycle device is not limited to an air conditioner configured with one indoor unit connected to one outdoor unit (so-called room air conditioner (RAC)). The refrigeration cycle device may be an air conditioner configured with multiple indoor units connected to one or multiple outdoor units (so-called package air conditioner (PAC) or building multi-air conditioner (VRF)). Alternatively, the refrigeration cycle device is not limited to an air conditioner, and may be a freezing or refrigeration device such as a refrigerator or a freezer.

[0093] [3. Aspects] As is clear from the above-described embodiments and modifications, the present disclosure includes the following aspects. In the following, reference numerals are given in parentheses only to clarify the correspondence with the embodiments. Note that, in consideration of readability of the text, the reference numerals in parentheses may be omitted from the second and subsequent times.

[0094] The first aspect is a refrigeration cycle device (1) comprising a refrigeration cycle circuit (2) including a compressor (4), a condenser (first heat exchanger 5, second heat exchanger 7), an expansion valve (6), and an evaporator (first heat exchanger 5, second heat exchanger 7), through which a working medium (20) circulates, and a control device (3; 3A; 3B) for controlling the refrigeration cycle circuit (2). The working medium (20) contains an ethylene-based fluoroolefin as a refrigerant component. The compressor (4) comprises a sealed container (40) forming a flow path for the working medium (20), a compression mechanism (41) located within the sealed container (40) for compressing the working medium (20), and an electric motor (42) located within the sealed container (40) for operating the compression mechanism (41). The control device (3; 3A; 3B) includes a drive circuit (31) that drives the electric motor (42), a detection circuit (32) that detects insulation deterioration of windings (Lu, Lv, Lw) of the electric motor (42), and a control circuit (33) that has a first control mode that controls the refrigeration cycle circuit (2) under a first condition and a second control mode that controls the refrigeration cycle circuit (2) under a second condition under which at least one of a maximum pressure and a maximum temperature of the working medium (20) in the compressor (4) is lower than the first condition, and that selects the second control mode when insulation deterioration of the windings (Lu, Lv, Lw) of the electric motor (42) is detected by the detection circuit (32). This aspect makes it possible to suppress a disproportionation reaction of the working medium (20).

[0095] A second aspect is a refrigeration cycle apparatus (1) based on the first aspect. In this aspect, the control circuit (33) determines whether the detection circuit (32) has detected insulation degradation of the windings (Lu, Lv, Lw) of the electric motor (42) before the drive circuit (31) drives the electric motor (42). The control circuit (33) executes the first control mode when the detection circuit (32) has not detected insulation degradation of the windings (Lu, Lv, Lw) of the electric motor (42), and executes the second control mode when the detection circuit (32) has detected insulation degradation of the windings (Lu, Lv, Lw) of the electric motor (42). This aspect can improve the safety of the operation of the refrigeration cycle apparatus (1).

[0096] A third aspect is a refrigeration cycle apparatus (1) based on the first or second aspect. In this aspect, the second control mode controls the refrigeration cycle circuit (2) so that the pressure of the working medium (20) in the compressor (4) is equal to or lower than a predetermined pressure and the temperature of the working medium (20) in the compressor is equal to or lower than a predetermined temperature. The predetermined pressure and the predetermined temperature are set so that a disproportionation reaction of the working medium (20) does not proceed even if a discharge phenomenon occurs in the windings (Lu, Lv, Lw) of the electric motor (42) in the sealed container (40). This aspect enables the refrigeration cycle apparatus (1) to continue operating while suppressing the disproportionation reaction of the working medium (20).

[0097] A fourth aspect is a refrigeration cycle device (1) based on the first or second aspect. In this aspect, the refrigeration cycle circuit (2) includes a first heat exchanger (5) that performs heat exchange between outside air and the working medium (20) and a second heat exchanger (7) that performs heat exchange between room air and the working medium (20). The control circuit (33) has a function of performing a cooling operation in which the refrigeration cycle circuit (2) is controlled so that the first heat exchanger (5) functions as the condenser and the second heat exchanger (7) functions as the evaporator, and a heating operation in which the refrigeration cycle circuit (2) is controlled so that the first heat exchanger (5) functions as the evaporator and the second heat exchanger (7) functions as the condenser. The second control mode stops the operation of the motor (42) by the drive circuit (31) when the temperature of the outside air exceeds an upper limit temperature during the cooling operation, or stops the operation of the motor (42) by the drive circuit (31) when the temperature of the outside air falls below a lower limit temperature during the heating operation. This aspect can improve the safety of the operation of the refrigeration cycle apparatus (1).

[0098] A fifth aspect is a refrigeration cycle apparatus (1) based on any one of the first to fourth aspects. In this aspect, the detection circuit (32) measures at least one of an impulse response, a resistance value, and an inductance of the windings (Lu, Lv, Lw) of the electric motor (42), and detects insulation degradation of the windings (Lu, Lv, Lw) of the electric motor (42) based on at least one of comparing an evaluation value of the impulse response, the resistance value, and the inductance of the windings (Lu, Lv, Lw) of the electric motor (42) with a threshold value and comparing at least one of the evaluation values ​​of the impulse response, the resistance value, and the inductance of the plurality of windings (Lu, Lv, Lw) of the electric motor (42) with each other. This aspect enables improved accuracy in detecting insulation degradation of the windings (Lu, Lv, Lw) of the electric motor (42).

[0099] A sixth aspect is a refrigeration cycle apparatus (1) based on the fifth aspect. In this aspect, the detection circuit (32) measures at least one of an impulse response, a resistance value, and an inductance of the windings (Lu, Lv, Lw) of the electric motor (42) by utilizing power supply lines (Pu, Pv, Pw) from the drive circuit (31) to the windings (Lu, Lv, Lw) of the electric motor (42). This aspect enables a simplification of the configuration of the control device.

[0100] A seventh aspect is a refrigeration cycle device (1) based on the sixth aspect. In this aspect, the detection circuit (32) is disposed on the same substrate (34) as the control circuit (33), or forms an integrated circuit (35) together with the control circuit (33). This aspect enables the configuration of the control device to be simplified.

[0101] An eighth aspect is a refrigeration cycle device (1) based on any one of the first to seventh aspects. In this aspect, the ethylene-based fluoroolefin includes an ethylene-based fluoroolefin that undergoes a disproportionation reaction. This aspect makes it possible to suppress the disproportionation reaction of the working fluid (20).

[0102] A ninth aspect is a refrigeration cycle apparatus (1) based on any one of the first to eighth aspects. In this aspect, the ethylene-based fluoroolefin is 1,1,2-trifluoroethylene, trans-1,2-difluoroethylene, cis-1,2-difluoroethylene, 1,1-difluoroethylene, tetrafluoroethylene, or monofluoroethylene. This aspect makes it possible to suppress the disproportionation reaction of the working medium (20).

[0103] A tenth aspect is a refrigeration cycle apparatus (1) based on any one of the first to ninth aspects. In this aspect, the working fluid (20) further contains difluoromethane as a refrigerant component. This aspect makes it possible to suppress the disproportionation reaction of the working fluid (20).

[0104] An eleventh aspect is a refrigeration cycle apparatus (1) based on any one of the first to tenth aspects. In this aspect, the working medium (20) further contains saturated hydrocarbons. This aspect makes it possible to suppress disproportionation reactions of the working medium (20).

[0105] A twelfth aspect is a refrigeration cycle apparatus (1) based on any one of the first to eleventh aspects. In this aspect, the working fluid (20) contains a haloalkane having 1 or 2 carbon atoms as a disproportionation inhibitor that suppresses the disproportionation reaction of the ethylene-based fluoroolefin. This aspect makes it possible to suppress the disproportionation reaction of the working fluid (20).

[0106] A thirteenth aspect is a refrigeration cycle apparatus (1) based on the eleventh aspect. In this aspect, the saturated hydrocarbon includes n-propane. This aspect makes it possible to suppress the disproportionation reaction of the working medium (20).

[0107] The second to thirteenth aspects are optional elements and are not essential.

[0108] The present disclosure is applicable to a refrigeration cycle device, specifically, a refrigeration cycle device in which a working fluid contains an ethylene-based fluoroolefin as a refrigerant component.

[0109] REFRIGERATION CYCLE DEVICE 1 Refrigeration cycle device 2 Refrigeration cycle circuit 20 Working medium 3, 3A, 3B Control device 31 Drive circuit 32 Detection circuit 33 Control circuit 34 Substrate 35 Integrated circuit Pu, Pv, Pw Power supply line 4 Compressor 40 Sealed container 41 Compression mechanism 42 Electric motor Lu, Lv, Lw Winding 5 First heat exchanger (condenser, evaporator) 6 Expansion valve 7 Second heat exchanger (condenser, evaporator)

Claims

1. a refrigeration cycle circuit including a compressor, a condenser, an expansion valve, and an evaporator, in which a working medium circulates; a control device for controlling the refrigeration cycle circuit; Equipped with the working fluid contains an ethylene-based fluoroolefin as a refrigerant component, The compressor is a sealed container that forms a flow path for the working medium; a compression mechanism located within the sealed container and compressing the working medium; an electric motor located within the sealed container for operating the compression mechanism; Equipped with The control device a drive circuit for driving the electric motor; a detection circuit for detecting insulation deterioration of the windings of the electric motor; a control circuit having a first control mode for controlling the refrigeration cycle circuit under a first condition and a second control mode for controlling the refrigeration cycle circuit under a second condition under which at least one of a maximum pressure and a maximum temperature of the working medium in the compressor is lower than that under the first condition, and which selects the second control mode when insulation deterioration of a winding of the electric motor is detected by the detection circuit; having Refrigeration cycle equipment.

2. the control circuit determines whether the detection circuit has detected insulation deterioration of a winding of the electric motor before driving the electric motor with the drive circuit; The control circuit When the detection circuit does not detect insulation deterioration of the winding of the electric motor, the first control mode is executed; When the detection circuit detects insulation deterioration of the winding of the electric motor, the second control mode is executed. The refrigeration cycle device according to claim 1.

3. the second control mode controls the refrigeration cycle circuit so that the pressure of the working medium in the compressor is equal to or lower than a predetermined pressure and the temperature of the working medium in the compressor is equal to or lower than a predetermined temperature; the predetermined pressure and the predetermined temperature are set so that a disproportionation reaction of the working fluid does not proceed even if a discharge phenomenon occurs in the winding of the electric motor in the sealed container. The refrigeration cycle device according to claim 1 or 2.

4. the refrigeration cycle circuit includes a first heat exchanger that performs heat exchange between outside air and the working medium, and a second heat exchanger that performs heat exchange between indoor air and the working medium, the control circuit has a function of executing a cooling operation of controlling the refrigeration cycle circuit so that the first heat exchanger functions as the condenser and the second heat exchanger functions as the evaporator, and a heating operation of controlling the refrigeration cycle circuit so that the first heat exchanger functions as the evaporator and the second heat exchanger functions as the condenser, The second control mode stops the operation of the electric motor by the drive circuit when the temperature of the outside air exceeds an upper limit temperature during the cooling operation, or stops the operation of the electric motor by the drive circuit when the temperature of the outside air falls below a lower limit temperature during the heating operation. The refrigeration cycle device according to claim 1 or 2.

5. The detection circuit measuring at least one of an impulse response, a resistance, and an inductance of a winding of the motor; detecting insulation deterioration of the windings of the electric motor based on at least one of comparing at least one of an evaluation value of an impulse response, a resistance value, and an inductance of the windings of the electric motor with a threshold value and comparing at least one of an evaluation value of an impulse response, a resistance value, and an inductance of the plurality of windings of the electric motor with each other; The refrigeration cycle device according to claim 1 or 2.

6. the detection circuit measures at least one of an impulse response, a resistance, and an inductance of the winding of the motor using a power supply line from the drive circuit to the winding of the motor; The refrigeration cycle device according to claim 5.

7. The detection circuit is formed on the same substrate as the control circuit or integrally with the control circuit. The refrigeration cycle device according to claim 6.

8. The ethylenic fluoroolefin includes an ethylenic fluoroolefin that undergoes a disproportionation reaction. The refrigeration cycle device according to claim 1 or 2.

9. The ethylenic fluoroolefin is 1,1,2-trifluoroethylene, trans-1,2-difluoroethylene, cis-1,2-difluoroethylene, 1,1-difluoroethylene, tetrafluoroethylene, or monofluoroethylene; The refrigeration cycle device according to claim 1 or 2.

10. The working medium further contains difluoromethane as the refrigerant component. The refrigeration cycle device according to claim 1 or 2.

11. The working medium further comprises a saturated hydrocarbon. The refrigeration cycle device according to claim 1 or 2.

12. the working fluid contains a haloalkane having 1 or 2 carbon atoms as a disproportionation inhibitor that suppresses the disproportionation reaction of the ethylenic fluoroolefin, The refrigeration cycle device according to claim 1 or 2.

13. The saturated hydrocarbons include n-propane. The refrigeration cycle device according to claim 11.