Refrigeration cycle device

Abstract

Provided is a refrigeration cycle device capable of suppressing a disproportionation reaction of a working medium. A refrigeration cycle device (1) includes a compressor (4) and a control device (3) that controls a refrigeration cycle circuit in which a working medium circulates. The working medium contains an ethylene-based fluoroolefin as a refrigerant component. A compressor (4) is provided with: a sealed container (40) that constitutes a flow path for a working medium; the compression mechanism (41) and the motor (42) are located in the sealed container (40). The control device (3) has: a drive circuit (31) that drives the motor (42); a detection circuit (32) that detects insulation deterioration of a winding of the motor (42); and a control circuit (33) 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 in which at least one of the maximum pressure and the maximum temperature of the working medium in the compressor (4) is lower than the first condition. When the detection circuit (32) detects insulation degradation of the winding of the motor (42), the second control mode is selected.

Description

Technical Field

[0001] The present invention relates to a refrigeration cycle device. Background Art

[0002] In the prior art, R410A is mostly used as a working medium (heat medium, refrigerant) for refrigeration cycle devices. However, the global warming potential (GWP) of R410A is as high as 2090. Therefore, from the perspective of preventing global warming, research and development of working media with a smaller GWP is carried out. Patent document 1 discloses 1,1,2-trifluoroethylene (HFO1123) as a working medium with a smaller GWP than R410A. Patent document 2 discloses 1,2-difluoroethylene (HFO1132) as a working medium with a smaller GWP than R410A.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2012 / 157764

[0006] Patent Document 2: International Publication No. 2012 / 157765 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In particular, HFO1123 and HFO1132 have lower GWP than R410A, so their stability is lower than R410A. For example, due to the generation of free radicals, the disproportionation reaction of HFO1123 or HFO1132 progresses, and HFO1123 and HFO1132 may change into other compounds.

[0009] The present invention provides a refrigeration cycle device capable of suppressing the disproportionation reaction of a working medium.

[0010] Methods for solving problems

[0011] A refrigeration cycle device according to one embodiment of the present invention includes: a refrigeration cycle circuit including a compressor, a condenser, an expansion valve, and an evaporator, in which a working medium circulates; and a control device for controlling the refrigeration cycle circuit. The working medium contains ethylene-based fluoroolefin as a refrigerant component. The compressor includes: a closed container constituting a flow path of the working medium; a compression mechanism located in the closed container and compressing the working medium; and a motor located in the closed container and actuating the compression mechanism. The control device includes: a drive circuit for driving the motor; a detection circuit for detecting insulation degradation of the motor winding; and 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 in which at least one of the maximum pressure and the maximum temperature of the working medium in the compressor is lower than the first condition, and the second control mode is selected when insulation degradation of the motor winding is detected in the detection circuit.

[0012] Effects of the Invention

[0013] The aspect of the present invention can suppress the disproportionation reaction of the working medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a block diagram of a configuration example of a refrigeration cycle device according to an embodiment.

[0015] Figure 2 yes Figure 1 A schematic diagram of a structural example of a compressor and a control device of a refrigeration cycle device.

[0016] Figure 3 yes Figure 1 A schematic diagram of an example of the configuration of a motor and a control device for a compressor of a refrigeration cycle device.

[0017] Figure 4 yes Figure 2 A flowchart of an example of the operation of a control circuit of a control device.

[0018] Figure 5 This is a schematic diagram of a configuration example of a compressor and a control device of a refrigeration cycle device according to Modification 1.

[0019] Figure 6 This is a schematic diagram of a configuration example of a compressor and a control device of a refrigeration cycle device according to Modification Example 2. DETAILED DESCRIPTION

[0020] [1. Implementation Method]

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, depending on the circumstances. However, the following embodiments are examples for illustrating the present invention, and are not intended to limit the present invention to the following contents. Unless otherwise specified, the positional relationships such as up, down, left, and right are based on the positional relationships shown in the accompanying drawings. The figures described in the following embodiments are schematic figures, and the ratios of the sizes and thicknesses of the components in the figures may not necessarily reflect the actual dimensional ratios. In addition, the dimensional ratios of the components are not limited to the ratios shown in the accompanying drawings.

[0022] In addition, in the following description, when it is necessary to distinguish multiple components from each other, prefixes such as "1st" and "2nd" are marked on the names of the components. However, when the components can be distinguished from each other by the figure marks marked on the components, the prefixes such as "1st" and "2nd" are sometimes omitted in consideration of the readability of the article.

[0023] [1.1 Structure]

[0024] Figure 1 It is a block diagram of a configuration example of the refrigeration cycle device 1 according to the present embodiment. Figure 1 The refrigeration cycle device 1 configures, for example, an air conditioner capable of performing cooling operation and heating operation.

[0025] Figure 1 The refrigeration cycle device 1 includes a refrigeration cycle circuit 2 and a control device 3.

[0026] The refrigeration cycle circuit 2 constitutes a flow path for the circulation of the working medium. In the present embodiment, the working medium contains ethylene fluoroolefin as a refrigerant component. The ethylene fluoroolefin may be an ethylene fluoroolefin that undergoes a disproportionation reaction. Examples of ethylene fluoroolefins produced by the 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), tetrafluoroethylene (CF2=CF2, FO1114), and monofluoroethylene (HFO-1141).

[0027] The working medium may contain a plurality of refrigerant components. The working medium may also contain ethylene fluoroolefins as the main refrigerant component and compounds other than ethylene fluoroolefins as the secondary refrigerant component. Examples of secondary refrigerant components include hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), saturated hydrocarbons, and carbon dioxide. Examples of hydrofluorocarbons (HFCs) include difluoromethane, difluoroethane, trifluoroethane, tetrafluoroethane, pentafluoroethane, pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, and heptafluorocyclopentane. Examples of hydrofluoroolefins (HFOs) include monofluoropropylene, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, and hexafluorobutene. 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), and methylcyclobutane.

[0028] The working medium may also contain a disproportionation inhibitor that inhibits the disproportionation reaction of ethylene-based fluoroolefins. Examples of disproportionation inhibitors include saturated hydrocarbons or halogenated alkanes. 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, etc. Among the above examples, n-propane is preferred. Examples of halogenated alkanes include halogenated alkanes having 1 or 2 carbon atoms. Examples of halogenated alkanes having 1 carbon atom (i.e., methyl halides) include (mono)iodomethane (CH3I), diiodomethane (CH2I2), dibromomethane (CH2Br2), bromomethane (CH3Br), dichloromethane (CH2Cl2), chloroiodomethane (CH2ClI), dibromochloromethane (CHBr2Cl), tetraiodomethane (CI4), carbon tetrabromide (CBr4), bromotrichloromethane (CBrCl3), dibromodichloromethane (CBr2Cl2), tribromofluoromethane (CBr3F), fluorodiiodomethane (CHFI2), difluorodiiodomethane (CF2I2), dibromodifluoromethane (CBr2F2), trifluoroiodomethane (CF3I), and difluoroiodomethane (CHF2I). Examples of halogenated alkanes having 2 carbon atoms (i.e., halogenated ethanes) include 1,1,1-trifluoro-2-iodoethane (CF3CH2I), monoiodoethane (CH3CH2I), monobromoethane (CH3CH2Br), 1,1,1-triiodoethane (CH3CI3), etc. The working medium may contain one or more halogenated alkanes having 1 or 2 carbon atoms. That is, only one halogenated alkanes having 1 or 2 carbon atoms may be used, or two or more halogenated alkanes having 1 or 2 carbon atoms may be used in combination.

[0029] Figure 1The refrigeration cycle circuit 2 includes a compressor 4 , a first heat exchanger 5 , an expansion valve 6 , a second heat exchanger 7 , and a four-way valve 8 .

[0030] Figure 1 The refrigeration cycle device 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 performs heat exchange between external air and a working medium 20. The outdoor unit 1a also includes a first fan 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 performs heat exchange between indoor air and a working medium 20. The indoor unit 1b also includes a second fan 7a for promoting heat exchange in the second heat exchanger 7.

[0031] exist Figure 1 In the refrigeration cycle 2, the compressor 4 compresses the working medium to increase the pressure of the working medium. The compressor 4 will be described in detail later. The first heat exchanger 5 and the second heat exchanger 7 perform heat exchange between the working medium circulating in the refrigeration cycle 2 and the external air (for example, external air or indoor 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 in the refrigeration cycle 2 between a first direction corresponding to cooling operation and a second direction corresponding to heating operation.

[0032] In this embodiment, the first direction is Figure 1 As indicated by the solid arrow A1 , the working medium circulates in the refrigeration cycle 2 in the order of the compressor 4 , the first heat exchanger 5 , the expansion valve 6 , and the second heat exchanger 7 .

[0033] In cooling operation, the compressor 4 compresses and discharges the gaseous working medium, whereby the gaseous working medium is sent to the first heat exchanger 5 via the four-way valve 8. The first heat exchanger 5 performs heat exchange between the outside air and the gaseous working medium, and the gaseous working medium is condensed and liquefied. The liquid working medium is decompressed by the expansion valve 6 and sent to the second heat exchanger 7. In the second heat exchanger 7, the liquid working medium and the indoor air perform heat exchange, and the gaseous working medium evaporates and becomes a gaseous working medium. The gaseous working medium returns to the compressor 4 via the four-way valve 8. In cooling operation, the first heat exchanger 5 functions as a condenser, and the second heat exchanger 7 functions as an evaporator. Therefore, the indoor unit 1b sends air cooled by heat exchange in the second heat exchanger 7 to the room during cooling.

[0034] In this embodiment, the second direction is Figure 1As indicated by the dotted arrow A2 , the working medium circulates in the refrigeration cycle 2 in the order of the compressor 4 , the second heat exchanger 7 , the expansion valve 6 , and the first heat exchanger 5 .

[0035] In the heating operation, the compressor 4 compresses and discharges the gaseous working medium, and the gaseous working medium is sent to the second heat exchanger 7 via the four-way valve 8. The second heat exchanger 7 performs heat exchange between the indoor air and the gaseous working medium, and the gaseous working medium is condensed and liquefied. The liquid working medium is decompressed by the expansion valve 6 and sent to the first heat exchanger 5. In the first heat exchanger 5, the liquid working medium and the outside air are heat exchanged, and the gaseous working medium evaporates and becomes a gaseous working medium. The gaseous working medium returns to the compressor 4 via the four-way valve 8. In the heating operation, the first heat exchanger 5 functions as an evaporator, and the second heat exchanger 7 functions as a condenser. Therefore, the indoor unit 1b sends air heated by the heat exchange in the second heat exchanger 7 to the room during heating.

[0036] Figure 1 The control device 3 controls the refrigeration cycle 2. More specifically, the control device 3 controls the compressor 4, the first fan 5a, the expansion valve 6, the second fan 7a, and the four-way valve 8 of the refrigeration cycle 2. Figure 2 It is a schematic diagram of a configuration example of the compressor 4 and the control device 3.

[0037] The compressor 4 is, for example, a hermetic compressor, and may be a rotary compressor, a scroll compressor, or other known compressors. Figure 2 The compressor 4 includes a closed container 40 , a compression mechanism 41 , and a motor 42 .

[0038] Figure 2 The sealed container 40 constitutes a flow path of the working medium 20. The sealed container 40 has a suction pipe 401 and a discharge pipe 402. The working medium 20 is sucked into the sealed container 40 from the suction pipe 401, and after being compressed by the compression mechanism 41, it is discharged to the outside of the sealed container 40 from the discharge pipe 402. 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 constitutes an oil storage part for storing a mixed liquid of the working medium 20 and the lubricating oil.

[0039] The compression mechanism 41 is located in the sealed container 40 and compresses the working medium 20. The compression mechanism 41 may be a conventionally known structure and may include, for example, a cylinder forming a compression chamber, a rolling piston disposed in the compression chamber in the cylinder, and a crankshaft coupled to the rolling piston.

[0040] The electric motor 42 is located in the sealed container 40 and operates the compression mechanism 41. The electric motor 42 is, for example, a brushless motor (three-phase brushless motor). Figure 3 4 is a schematic diagram of a configuration example of the motor 42 and the control device 3. Figure 3 As shown, the motor 42 has a plurality of windings (stator windings) Lu, Lv, Lw. The plurality of windings include a U-phase winding Lu, a V-phase winding Lv, and a W-phase winding Lw. The motor 42, for example, includes a rotor fixed to a crankshaft of a compression mechanism 41 and a stator arranged around the rotor. The stator is constructed, for example, by winding the stator windings (magnetic wires, etc.) on the stator core (electromagnetic steel plates, etc.) Lu, Lv, Lw in a concentrated or dispersed manner via insulating paper. The windings Lu, Lv, Lw are covered by insulating components. Examples of insulating components include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), aromatic polyamide polymers, polyphenylene sulfide (PPS), and the like.

[0041] In order to prevent the liquid in the compression chamber of the compression mechanism 41 from being compressed, the compressor 4 may include a liquid accumulator. The liquid 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 interior of the closed container 40.

[0042] Figure 2 and Figure 3 The control device 3 includes a driving circuit 31 , a detection circuit 32 and a control circuit 33 .

[0043] The drive circuit 31 drives the motor 42 . Figure 2 The drive circuit 31 supplies drive power to the motor 42 based on the power from the power source 10. In the present embodiment, the power source 10 is an AC power source. The drive circuit 31 supplies drive power to the motor 42 based on the AC power from the power source 10. In particular, the drive circuit 31 supplies three-phase AC power as drive power to the motor 42. The drive circuit 31 includes a converter circuit 311 and an inverter circuit 312.

[0044] The converter circuit 311 converts the 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 a plurality of diodes D1 to D4. The power supply 10 is connected between the input terminals of the rectifier circuit 311a (the connection point of the diodes D1 and D2, and the connection point of the diodes D3 and D4), and the smoothing circuit 311b is connected between the output terminals of the rectifier circuit 311a (the connection point of the diodes D1 and D3, and the connection point of the diodes D2 and D4). The smoothing circuit 311b includes a series circuit of an inductor L1 and a capacitor C1, and smoothes the voltage between the output terminals of the rectifier circuit 311a and outputs it as a voltage between both ends of the capacitor C1. Figure 2 The structures of the rectifying circuit 311a and the smoothing circuit 311b are well known, so their detailed description is omitted.

[0045] The inverter circuit 312 supplies three-phase AC power to the motor 42 based on the DC power from the converter circuit 311. Figure 2 The inverter circuit 312 supplies three-phase AC power to the 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.

[0046] Figure 2 The semiconductor switching elements U1 and U2 form a series circuit. The series circuit of the semiconductor switching elements U1 and U2 is connected in parallel with the capacitor C1 of the converter circuit 311. The connection point of the semiconductor switching elements U1 and U2 is connected to the motor 42 via the U-phase power supply line Pu. Figure 3 As shown, the power supply line Pu is connected to one end (U-phase input terminal) of the U-phase winding Lu of the motor 42 .

[0047] Figure 2 The semiconductor switching elements V1 and V2 form a series circuit. The series circuit of the semiconductor switching elements V1 and V2 is connected in parallel with 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 the power supply line Pv of the V phase. Figure 3 As shown, the power supply line Pv is connected to one end (V-phase input terminal) of the V-phase winding Lv of the motor 42 .

[0048] Figure 2 The semiconductor switching elements W1 and W2 form a series circuit. The series circuit of the semiconductor switching elements W1 and W2 is connected in parallel with 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 the power supply line Pw of the W phase. Figure 3 As shown, the power supply line Pw is connected to one end (W-phase input terminal) of the W-phase winding Lw of the motor 42 .

[0049] In the inverter circuit 312, a series circuit of semiconductor switching elements U1 and U2 constitutes a branch of phase U. A series circuit of semiconductor switching elements V1 and V2 constitutes a branch of phase V. A series circuit of semiconductor switching elements W1 and W2 constitutes a branch of phase W. In this case, the semiconductor switching elements U1, U2, V1, V2, W1, and W2 are also referred to as arms.

[0050] Figure 2 The structure of the inverter circuit 312 is well known, so its detailed description is omitted.

[0051] The detection circuit 32 detects insulation degradation of the windings (U-phase winding Lu, V-phase winding Lv, and W-phase winding Lw) of the motor 42 .

[0052] In the present embodiment, the detection circuit 32 detects 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 evaluation value of the pulse response of the windings Lu, Lv, and Lw of the motor 42. More specifically, the detection circuit 32 measures the pulse response of the windings Lu, Lv, and Lw of the motor 42. As an example, the pulse response is provided based on the time change of the current or voltage of the windings Lu, Lv, and Lw generated by applying a pulse voltage to the windings Lu, Lv, and Lw of the motor 42.

[0053] Figure 3 The detection circuit 32 measures the pulse response of the windings Lu, Lv, Lw of the motor 42 using the power supply lines Pu, Pv, Pw from the drive circuit 31 to the windings Lu, Lv, Lw of the motor 42. Figure 3 The detection circuit 32 can apply a pulse voltage to the windings Lu, Lv of the motor 42 through the power supply lines Pu, Pv. Figure 3 The detection circuit 32 can apply a pulse voltage to the windings Lv, Lw of the motor 42 through the power supply lines Pv, Pw. Figure 3 The detection circuit 32 can apply a pulse voltage to the windings Lw, Lu of the motor 42 through the power supply lines Pw, Pu.

[0054] The detection circuit 32 detects insulation degradation of the windings Lu, Lv, Lw of the motor 42 based on comparison with the evaluation value of the pulse response of the windings Lu, Lv, Lw of the motor 42 obtained by measurement. Examples of the evaluation value of the pulse response include a numerical value representing the area (integral value) of the pulse response or the waveform of the pulse response. The detection circuit 32 may also determine that insulation degradation of the windings Lu, Lv, Lw of the motor 42 has occurred when the evaluation value of the pulse response of the windings Lu, Lv, Lw of the motor 42 is below a threshold. The threshold value can be set to be able to distinguish insulation degradation of the windings Lu, Lv, Lw based on the evaluation value of the windings Lu, Lv, Lw in normal conditions and the evaluation value when the insulation is degraded. The measurement of the pulse response of the windings Lu, Lv, Lw of the motor 42 may be either a direct measured value or an inferred value measured indirectly.

[0055] The control circuit 33 can be implemented, 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 a plurality of semiconductor switch 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 the present embodiment, the control circuit 33 also controls the opening 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.

[0056] The control circuit 33 has the function of executing cooling operation and heating operation. In cooling operation, the control circuit 33 controls the refrigeration cycle 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 2 so that the first heat exchanger 5 functions as an evaporator and the second heat exchanger 7 functions as a condenser.

[0057] The control circuit 33 has a plurality of control modes in cooling operation and heating operation. In the present 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 as the temperature management object of the refrigeration cycle device 1 is consistent with the 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 medium in the refrigeration cycle circuit 2 does not develop.

[0058] The main causes of the disproportionation reaction of the working medium are heat and free radicals. For example, it is considered that when free radicals are generated under high temperature and high pressure, the disproportionation reaction of the working medium develops. For example, free radicals may be generated due to the discharge phenomenon in the compressor 4. The discharge phenomenon in the compressor 4 may be caused by the insulation degradation of the windings Lu, Lv, and Lw of the motor 42. The insulation degradation of the windings Lu, Lv, and Lw of the motor 42 may eventually lead to the insulation breakdown of the motor 42. In the compressor 4, when the motor 42 is driven, heat is generated in the motor 42, so the heat dissipation of the motor 42 is required. It is very effective to use the working medium in the heat dissipation of the motor 42. From this point of view, the motor 42 is arranged in the sealed container 40 in a manner that can contact the working medium. However, when the motor 42 is broken down and the discharge phenomenon occurs, the discharge phenomenon directly affects the working medium, and as a result, free radicals may be generated under high temperature and high pressure. In this way, the occurrence of insulation degradation of the windings Lu, Lv, and Lw of the motor 42 is likely to promote the development of the disproportionation reaction of the working medium.

[0059] In this embodiment, when the detection circuit 32 does not detect insulation degradation of the windings Lu, Lv, and Lw of the motor 42, the control circuit 33 executes the first control mode. When the detection circuit 32 detects insulation degradation of the windings Lu, Lv, and Lw of the motor 42, the control circuit 33 executes the second control mode.

[0060] Next, the first control mode and the second control mode will be described in more detail.

[0061] As described above, the first control mode is a normal operation mode for controlling the refrigeration cycle circuit 2 so that the current temperature of the space as the temperature management target of the refrigeration cycle device 1 is consistent with the target temperature. In the present embodiment, the first control mode controls the refrigeration cycle circuit 2 under the first condition. The first condition includes controlling the drive circuit 31 so that the current temperature of the space as the temperature management target of the refrigeration cycle device 1 is consistent with the target temperature. As arbitrary elements, the first condition may include controlling the expansion valve 6, the first fan 5a, the second fan 7a, and the four-way valve 8 so that the current temperature of the space as the temperature management target of the refrigeration cycle device 1 is consistent with the target temperature. In the first control mode, the control circuit 33 controls the target value of the frequency of the three-phase alternating current output to the motor 42 of the compressor 4 through the drive circuit 31, the target value of the opening of the expansion valve 6, the target value of the rotation speed of the fan of the first fan 5a, the target value of the rotation speed of the fan of the second fan 7a, and the switching state of the four-way valve 8. The first control mode can set a target value of the frequency of the three-phase AC power, a target value of the opening degree of the expansion valve 6, a target value of the speed of the fan of the first blower 5a, and a target value of the speed of the fan of the second blower 7a based on the current temperature and the target temperature of the space as the temperature management object of the refrigeration cycle device 1. The switching state of the four-way valve 8 can be determined according to, for example, cooling operation, heating operation, or dehumidification operation.

[0062] As described above, the second control mode is a safety operation mode or a restricted operation mode for controlling the refrigeration cycle 2 to ensure that the disproportionation reaction of the working medium in the refrigeration cycle 2 does not develop. In the present embodiment, the second control mode controls the refrigeration cycle 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 medium 20 in the compressor 4 is lower than the first condition. That is, the second condition is set in a manner that the high temperature and high pressure environment in which the working medium 20 is placed is milder than 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 medium in the compressor 4 is lower than the first condition. As an arbitrary element, the second condition may include controlling the expansion valve 6, the first fan 5a, the second fan 7a, and the four-way valve 8 so that at least one of the maximum pressure and the maximum temperature of the working medium in the compressor 4 is lower than the first condition. If free radicals are generated under high temperature and high pressure, it is considered that the disproportionation reaction of the working medium develops, so in the second control mode, the refrigeration cycle 2 is controlled so as not to generate a high temperature and high pressure condition.

[0063] In the refrigeration cycle 2, there is a tendency that the pressure and temperature of the working medium in the compressor 4 increase as the operating load increases. For example, in cooling operation, the higher the temperature of the outside air, the greater the operating load. For example, in heating operation, the lower the temperature of the outside air, the greater the operating load. The increase in operating load is one of the reasons for the increase in the maximum pressure or the maximum temperature of the working medium 20 in the compressor 4. In the second control mode, the operation of the motor 42 driven by the drive circuit 31 is stopped to ensure that the pressure of the working medium 20 in the compressor 4 reaches a pressure that may cause the disproportionation reaction of the working medium 20 to develop when a discharge phenomenon occurs in the windings Lu, Lv, and Lw of the motor 42 in the closed container 40 due to the increase in operating load, or the temperature of the working medium 20 in the compressor 4 reaches a temperature that may cause the disproportionation reaction of the working medium 20 to develop when a discharge phenomenon occurs in the windings Lu, Lv, and Lw of the motor 42 in the closed container 40. In this embodiment, in the second control mode, when the temperature of the outside air exceeds the upper limit temperature of the operation in cooling operation, the operation of the motor 42 driven by the drive circuit 31 is stopped. In the present embodiment, the second control mode stops the operation of the motor 42 driven by the drive circuit 31 when the temperature of the outside air is lower than the lower limit temperature of operation during the heating operation. The upper limit temperature of operation can be set based on whether the pressure of the working medium 20 in the compressor 4 has reached a pressure at which a disproportionation reaction of the working medium 20 may develop when a discharge phenomenon occurs in the windings Lu, Lv, Lw of the motor 42 in the closed container 40 during the cooling operation, and whether the temperature of the working medium 20 in the compressor 4 has reached a temperature at which a disproportionation reaction of the working medium 20 may develop when a discharge phenomenon occurs in the windings Lu, Lv, Lw of the motor 42 in the closed container 40. The lower limit temperature of operation can be appropriately set based on whether the pressure of the working medium 20 in the compressor 4 during the heating operation reaches a pressure at which the disproportionation reaction of the working medium 20 may develop when a discharge phenomenon occurs in the windings Lu, Lv, and Lw of the motor 42 in the closed container 40, and whether the temperature of the working medium 20 in the compressor 4 reaches a temperature at which the disproportionation reaction of the working medium 20 may develop when a discharge phenomenon occurs in the windings Lu, Lv, and Lw of the motor 42 in the closed container 40. Thus, under the second condition, when a discharge phenomenon occurs in the windings Lu, Lv, and Lw of the motor 42 in the closed container 40, the refrigeration cycle 2 is not operated under an operation load at which the disproportionation reaction of the working medium 20 may develop. This is equivalent to setting upper limit values ​​for the pressure and temperature of the working medium 20 in the compressor 4. That is, under the second condition, at least one of the maximum pressure and the maximum temperature of the working medium in the compressor 4 is lower than the first condition. Thus, the safety of the operation of the refrigeration cycle device 1 can be improved. In addition, the second control mode stops the operations of the first fan 5a and the second fan 7a.In the second control mode, the switching state of the four-way valve 8 does not change in particular and can be maintained in the previous state.

[0064] [1.2 Action]

[0065] Below, refer to Figure 4 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. Figure 4 This is a flowchart of an example of the operation of the control circuit 33 of the control device 3 .

[0066] Before the control circuit 33 drives the motor 42 by the drive circuit 31 , the detection circuit 32 executes a process for detecting insulation degradation of the windings Lu, Lv, and Lw of the motor 42 ( S11 ).

[0067] If the detection circuit 32 does not detect insulation degradation of the windings Lu, Lv, and Lw of the motor 42 ( S12 ; No), the control circuit 33 executes the first control mode to control the refrigeration cycle 2 under the first condition ( S13 ).

[0068] When the detection circuit 32 detects insulation degradation of the windings Lu, Lv, and Lw of the motor 42 ( S12 ; Yes), the control circuit 33 executes the second control mode to control the refrigeration cycle 2 under the second condition ( S14 ).

[0069] In this way, the control circuit 33 determines whether the detection circuit 32 detects insulation degradation of the windings Lu, Lv, and Lw of the motor 42 before the drive circuit 31 drives the motor 42. When the detection circuit 32 does not detect insulation degradation of the windings Lu, Lv, and Lw of the motor 42, the control circuit 33 executes the first control mode. When the detection circuit 32 detects insulation degradation of the windings Lu, Lv, and Lw of the motor 42, the control circuit 33 executes the second control mode. Therefore, when insulation degradation occurs in the windings Lu, Lv, and Lw of the motor 42 and the disproportionation reaction of the working medium is likely to develop, the normal operation mode is switched to the safe operation mode, thereby suppressing the disproportionation reaction of the working medium.

[0070] [1.3 Effects, etc.]

[0071] The refrigeration cycle device 1 described above includes: a refrigeration cycle circuit 2, which includes a compressor 4, a condenser (a first heat exchanger 5, a second heat exchanger 7), an expansion valve 6 and an evaporator (a first heat exchanger 5, a second heat exchanger 7), and a working medium 20 circulates; and a control device 3, which controls the compressor 4 of the refrigeration cycle circuit 2. The working medium 20 contains ethylene-based fluoroolefin as a refrigerant component. The compressor 4 includes: a closed container 40 constituting a flow path of the working medium 20; a compression mechanism 41 located in the closed container 40 and compressing the working medium 20; and a motor 42 located in the closed container 40 and actuating the compression mechanism 41. The control device 3 includes: a drive circuit 31 for driving the motor 42; a detection circuit 32 for detecting insulation degradation of the windings Lu, Lv, and Lw of the motor 42; and a control circuit 33, which has a first control mode for controlling the drive circuit 31 under a first condition, and a second control mode for controlling the drive circuit 31 under a second condition in which 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 the second control mode is selected when insulation degradation of the windings Lu, Lv, and Lw of the motor 42 is detected in the detection circuit 32. This structure can suppress the disproportionation reaction of the working medium 20.

[0072] In the refrigeration cycle device 1, the control circuit 33 determines whether the detection circuit 32 detects insulation degradation of the windings Lu, Lv, and Lw of the motor 42 before the drive circuit 31 drives the motor 42. When the detection circuit 32 does not detect insulation degradation of the windings Lu, Lv, and Lw of the motor 42, the control circuit 33 executes the first control mode, and when the detection circuit 32 detects insulation degradation of the windings Lu, Lv, and Lw of the motor 42, the control circuit 33 executes the second control mode. This structure can improve the safety of the operation of the refrigeration cycle device 1.

[0073] In the refrigeration cycle device 1, the refrigeration cycle circuit 2 includes a first heat exchanger 5 for performing heat exchange between the outside air and the working medium 20, and a second heat exchanger 7 for performing heat exchange between the indoor air and the working medium 20. The control circuit 33 has a function of performing a cooling operation and a heating operation, wherein the cooling operation 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, and the heating operation 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. In the second control mode, the operation of the motor 42 driven by the drive circuit 31 is stopped when the temperature of the outside air exceeds the upper limit temperature of the operation in the cooling operation, or the operation of the motor 42 driven by the drive circuit 31 is stopped when the temperature of the outside air is lower than the lower limit temperature of the operation in the heating operation. This structure can improve the safety of the operation of the refrigeration cycle device 1.

[0074] In the refrigeration cycle device 1, the detection circuit 32 measures at least one of the pulse response, resistance value and inductance of the windings Lu, Lv, Lw of the motor 42, and detects insulation degradation of the windings Lu, Lv, Lw of the motor 42 based on at least one of comparison of the pulse response, resistance value and inductance of the windings Lu, Lv, Lw of the motor 42 with a threshold value and comparison of the pulse response, resistance value and inductance of the plurality of windings Lu, Lv, Lw of the motor 42 with each other. This structure can improve the detection accuracy of insulation degradation of the windings Lu, Lv, Lw of the motor 42.

[0075] In the refrigeration cycle device 1, the detection circuit 32 uses the power supply lines Pu, Pv, Pw from the drive circuit 31 to the windings Lu, Lv, Lw of the motor 42 to measure at least one of the pulse response, resistance value and inductance of the windings Lu, Lv, Lw of the motor 42. This structure can simplify the structure of the control circuit.

[0076] In the refrigeration cycle device 1, the detection circuit 32 is arranged on the same substrate 34 as the control circuit 33. This structure can simplify the structure of the control device 3.

[0077] In the refrigeration cycle device 1 , the ethylene-based fluoroolefin includes an ethylene-based fluoroolefin that undergoes a disproportionation reaction. This structure can suppress the disproportionation reaction of the working medium 20 .

[0078] 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 structure can suppress the disproportionation reaction of the working medium 20 .

[0079] In the refrigeration cycle device 1 , the working medium 20 further contains difluoromethane as a refrigerant component. This structure can suppress the disproportionation reaction of the working medium 20 .

[0080] In the refrigeration cycle device 1 , the working medium 20 further contains saturated hydrocarbons. This structure can suppress the disproportionation reaction of the working medium 20 .

[0081] In the refrigeration cycle device 1 , the working medium 20 contains a halogenated alkane having 1 or 2 carbon atoms as a disproportionation inhibitor for suppressing the disproportionation reaction of ethylene-based fluoroolefin. This structure can suppress the disproportionation reaction of the working medium 20 .

[0082] In the refrigeration cycle device 1 , the saturated hydrocarbon includes normal propane. This structure can suppress the disproportionation reaction of the working medium 20 .

[0083] [2. Modifications]

[0084] The embodiments of the present invention are not limited to the above-mentioned embodiments. The above-mentioned embodiments can be variously modified according to design etc. as long as the problem of the present invention can be achieved. The following are modified examples of the above-mentioned embodiments. The modified examples described below can be appropriately combined and applied.

[0085] [2.1 Modification 1]

[0086] Figure 5 It is a schematic diagram of a configuration example of the compressor 4 and the control device 3A of the refrigeration cycle device according to the first modification. Figure 5 The control device 3A includes a driving circuit 31, a detection circuit 32 and a control circuit 33. Figure 5 In the control device 3A, the detection circuit 32 and the control circuit 33 together constitute an integrated circuit 35. That is, the detection circuit 32 and the control circuit 33 are not separate circuit components from each other, but are integrated as a single circuit component. Therefore, the space required for configuring the detection circuit 32 and the control circuit 33 can be reduced, and the structure of the control device 3A can be simplified. The integrated circuit 35 can also be configured on the same substrate as the drive circuit 31.

[0087] As described above, in the control device 3A of the refrigeration cycle apparatus, the detection circuit 32 and the control circuit 33 together constitute the integrated circuit 35. This configuration can simplify the configuration of the control device 3A.

[0088] [2.2 Modification 2]

[0089] Figure 6 It is a schematic diagram of a configuration example of a compressor 4 and a control device 3B of a refrigeration cycle device according to Modification 2.

[0090] Figure 6 The control device 3B includes: a driving circuit 31, a detection circuit 32, a control circuit 33, a pressure measurement circuit 36 ​​and a temperature measurement circuit 37.

[0091] The pressure measuring circuit 36 ​​measures the pressure of the working medium 20 in the compressor 4 . Figure 6 The pressure measuring circuit 36 ​​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 measuring 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 measuring circuit 36 ​​is, for example, a pressure sensor located in the sealed container 40. The pressure measuring circuit 36 ​​is not limited to a pressure sensor located in the sealed container 40. The pressure measuring circuit 36 ​​can directly or indirectly measure the working medium 20 in the compressor 4.

[0092] The temperature measuring circuit 37 measures the temperature of the working medium 20 in the compressor 4 . Figure 6The temperature measurement circuit 37 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 in the sealed container 40. The temperature measurement circuit 37 is not limited to a temperature sensor located in the sealed container 40. The temperature measurement circuit 37 can directly or indirectly measure the temperature of the working medium 20 in the compressor 4.

[0093] In this modification, the control circuit 33 executes the first control mode when the detection circuit 32 does not detect insulation degradation of the windings Lu, Lv, and Lw of the motor 42. When the detection circuit 32 detects insulation degradation of the windings Lu, Lv, and Lw of the motor 42, the control circuit 33 executes the second control mode.

[0094] The second control mode of this modification is similar to the second control mode of the embodiment, and is a safety operation mode or a restricted operation mode for controlling the refrigeration cycle 2 so that the disproportionation reaction of the working medium 20 in the refrigeration cycle 2 does not develop. In this modification, the second control mode controls the refrigeration cycle 2 so that the pressure of the working medium 20 in the compressor 4 becomes less than a predetermined pressure, and the temperature of the working medium 20 in the compressor 4 becomes less than a predetermined temperature. Specifically, in the second control mode, the control circuit 33 can set a target value of the frequency of the three-phase alternating current output to the motor 42 of the compressor 4 through the drive circuit 31, a target value of the opening of the expansion valve 6, a target value of the fan speed of the first fan 5a, and a target value of the fan speed of the second fan 7a, so that the pressure of the working medium 20 in the compressor 4 measured by the pressure measurement circuit 36 ​​becomes less than a predetermined pressure, and the temperature of the working medium 20 in the compressor 4 measured by the temperature measurement circuit 37 becomes less than a predetermined temperature. The switching state of the four-way valve 8 can be determined, for example, according to the cooling operation, the heating operation, or the dehumidification operation.

[0095] The prescribed pressure and the prescribed temperature are set in a manner that reduces the possibility of the development of the disproportionation reaction of the working medium 20, compared to the case where the refrigeration cycle circuit 2 is continuously controlled in the first control mode. In this modified example, the prescribed pressure and the prescribed temperature are set in a manner that the disproportionation reaction of the working medium 20 does not develop even when a discharge phenomenon occurs in the windings Lu, Lv, Lw of the motor 42 in the closed container 40. The prescribed pressure and the prescribed temperature can be appropriately set according to the composition of the working medium 20, etc. For example, the prescribed pressure and the prescribed temperature can also be set based on the test results of whether the disproportionation reaction of the working medium 20 develops in a state where a discharge phenomenon occurs in the windings Lu, Lv, Lw of the motor 42 in the closed container 40.

[0096] The predetermined pressure can be set based on the force of the working medium 20 in the normal operation range of the refrigeration cycle 2. For example, when the pressure of the working medium 20 in the normal operation range of the refrigeration cycle 2 is 6 MPa, the predetermined pressure is set to 5 MPa.

[0097] The specified temperature is, for example, lower than the safety temperature of the working medium 20 and lower than the heat resistance temperature of the insulating component of the motor 42 of the compressor 4. The safety temperature of the working medium 20 can be set based on the temperature at which the disproportionation reaction of the working medium 20 may occur under the pressure conditions during the normal operation of the refrigeration cycle device 1. As an example, the safety temperature of the working medium 20 is set to 150°C. The heat resistance temperature of the motor 42 of the compressor 4 is set, for example, based on the heat resistance temperature of the insulating component of the motor 42 of the compressor 4. For example, the heat resistance temperature of the insulating component of the motor 42 may also be the heat resistance temperature of the insulating component with the lowest heat resistance temperature among the insulating components of the motor 42. When the operation of the refrigeration cycle device 1 is continued in a state where the internal temperature exceeds the heat resistance temperature, the insulating paper is sometimes damaged, and at this time, the possibility of the discharge phenomenon becoming higher. As an example, the insulating component with the lowest heat resistance temperature in the motor 42 may be the insulating paper between the stator core (electromagnetic steel sheet, etc.) and the stator winding (magnetic wire, etc.). When the heat resistance grade of the insulating paper is, for example, Class E specified in JIS C 4003, the heat resistance temperature is 120°C. When the safety temperature of the working medium 20 is 150°C and the heat resistance temperature of the motor 42 of the compressor 4 is 120°C, the specified temperature is set to a temperature lower than 120°C. In this case, when considering the temperature of the working fluid and the temperature detection time difference between the stator and the heat dissipation, the safety margin can be set to, for example, about 5°C. Therefore, the specified temperature can be set to 115°C. Since the safety margin depends on the distance between the temperature measurement circuit 37 and the stator or the motor efficiency, it is not limited to 5°C and can be set to a value between 0 and 20°C. The heat resistance grade of the insulating paper is not limited to Class E, and may be Class B, Class F, etc. If the heat resistance grade is Class B, the heat resistance temperature is 130°C. If the safety temperature of the working medium 20 is 150°C, the specified temperature is set to a temperature lower than 130°C, for example, 125°C. If the heat resistance grade is Class F, the heat resistance temperature is 155°C. If the safe temperature of the working medium 20 is 150°C, the prescribed temperature is set to a temperature lower than 150°C, for example, 145°C.

[0098] 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 below the prescribed pressure, and the temperature of the working medium 20 in the compressor 4 is below the prescribed temperature. The prescribed pressure and the prescribed temperature are set in such a way that even if a discharge phenomenon occurs in the windings Lu, Lv, and Lw of the motor 42 in the closed container 40, the disproportionation reaction of the working medium 20 will not develop. This structure can continue the operation of the refrigeration cycle device while suppressing the disproportionation reaction of the working medium 20.

[0099] [2.3 Other Modifications]

[0100] In a modified example, in addition to comparing the evaluation value based on the pulse response of the windings Lu, Lv, Lw of the motor 42 with the threshold value, the detection circuit 32 can also detect insulation degradation of the windings Lu, Lv, Lw of the motor 42 based on the comparison of the evaluation values ​​of the pulse response of the plurality of windings Lu, Lv, Lw of the motor 42. The evaluation values ​​of the pulse response of the plurality of windings Lu, Lv, Lw of the motor 42 are usually the same value. Therefore, when the difference between the evaluation values ​​of the pulse response of any combination of the plurality of windings Lu, Lv, Lw of the motor 42 is greater than a specified value, the detection circuit 32 can also determine that insulation degradation has occurred in any of the windings Lu, Lv, Lw of the motor 42.

[0101] In a 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 instead of the non-pulse 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 the comparison of the resistance values ​​of the windings Lu, Lv, and Lw of the motor 42 with a threshold value. The measurement of the resistance values ​​of the windings Lu, Lv, and Lw of the motor 42 can be achieved by an existing well-known method, so the description is omitted. When the resistance values ​​of the windings Lu, Lv, and Lw of the motor 42 are below the threshold value, the detection circuit 32 may also determine that insulation degradation has occurred in the windings Lu, Lv, and Lw of the motor 42. The threshold value can be set so that insulation degradation of the windings Lu, Lv, Lw can be determined based on the resistance value of the windings Lu, Lv, Lw in normal state and the resistance value when insulation degradation occurs. Since the resistance value of the windings Lu, Lv, Lw can vary according to the temperature of the windings Lu, Lv, Lw, the threshold value can be a function of the temperature of the windings Lu, Lv, Lw. The measurement of the resistance value of the windings Lu, Lv, Lw of the motor 42 can be either a direct measured value or an inferred value obtained by indirect measurement.

[0102] In a modified example, in addition to comparing the resistance value of the windings Lu, Lv, Lw of the motor 42 with the threshold value, the detection circuit 32 can also detect insulation degradation of the windings Lu, Lv, Lw of the motor 42 based on comparison of the resistance values ​​of the plurality of windings Lu, Lv, Lw of the motor 42. The resistance values ​​of the plurality of windings Lu, Lv, Lw of the motor 42 are usually the same value. Therefore, when the difference in resistance values ​​of any combination of the plurality of windings Lu, Lv, Lw of the motor 42 is greater than a specified value, the detection circuit 32 can also determine that insulation degradation has occurred in any one of the windings Lu, Lv, Lw of the motor 42.

[0103] In a modified example, the detection circuit 32 may also measure the resistance values ​​of the windings Lu, Lv, Lw of the motor 42 by using the power supply lines Pu, Pv, Pw from the drive circuit 31 to the windings Lu, Lv, Lw of the motor 42. Figure 3 As shown, the detection circuit 32 can measure the resistance value 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 can measure the resistance value 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 can measure the resistance value of the series circuit of the windings Lw and Lu of the motor 42 via the power supply lines Pw and Pu. The resistance value of each winding Lu, Lv, and Lw is obtained by calculation.

[0104] In a 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 instead of the pulse response or the 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 the comparison of the inductance of the windings Lu, Lv, and Lw of the motor 42 with a threshold value. The measurement of the inductance of the windings Lu, Lv, and Lw of the motor 42 itself can be achieved by an existing well-known method, so the description is omitted. When the inductance of the windings Lu, Lv, and Lw of the motor 42 is below the threshold value, the detection circuit 32 may also determine that insulation degradation of the windings Lu, Lv, and Lw of the motor 42 has occurred. The threshold value can be set so that insulation degradation of the windings Lu, Lv and Lw can be determined based on the inductance of the windings Lu, Lv and Lw in normal state and the inductance when insulation degradation occurs. The inductance of the windings Lu, Lv and Lw of the motor 42 can be measured directly or estimated indirectly.

[0105] In a modified example, in addition to comparing the inductance of the windings Lu, Lv, Lw of the motor 42 with the threshold value, the detection circuit 32 can also detect insulation degradation of the windings Lu, Lv, Lw of the motor 42 based on the comparison of the inductances of the plurality of windings Lu, Lv, Lw of the motor 42. The inductances of the plurality of windings Lu, Lv, Lw of the motor 42 are usually the same value. Therefore, when the difference in inductance of any combination of the plurality of windings Lu, Lv, Lw of the motor 42 is greater than a specified value, the detection circuit 32 can also determine that insulation degradation has occurred in any one of the windings Lu, Lv, Lw of the motor 42.

[0106] In a modified example, the detection circuit 32 may also use the power supply lines Pu, Pv, Pw from the drive circuit 31 to the windings Lu, Lv, Lw of the motor 42 to measure the inductance of the windings Lu, Lv, Lw of the motor 42. Figure 3 As shown, the detection circuit 32 can measure the inductance of the series circuit of the windings Lu and Lv of the motor 42 through the power supply lines Pu and Pv. The detection circuit 32 can measure the inductance of the series circuit of the windings Lv and Lw of the motor 42 through the power supply lines Pv and Pw. The detection circuit 32 can measure the inductance of the series circuit of the windings Lw and Lu of the motor 42 through the power supply lines Pw and Pu. The inductance of each winding Lu, Lv, and Lw is obtained by calculation.

[0107] In a modified example, the detection circuit 32 may also detect insulation degradation of the windings Lu, Lv, Lw of the motor 42 using two or more of the pulse response, resistance value, and inductance of the windings Lu, Lv, Lw of the motor 42. Thus, the insulation degradation of the windings Lu, Lv, Lw of the motor 42 can be detected from multiple viewpoints, so the detection accuracy of the insulation degradation of the windings Lu, Lv, Lw of the motor 42 can be improved.

[0108] In this way, the detection circuit 32 may also measure at least one of the pulse response, resistance value, and inductance of the windings Lu, Lv, Lw of the motor 42, and detect insulation degradation of the windings Lu, Lv, Lw of the motor 42 based on at least one of comparison of the evaluation value of the pulse response, resistance value, and inductance of the windings Lu, Lv, Lw of the motor 42 with a threshold value, and comparison of the evaluation value of the pulse response, resistance value, and inductance of the plurality of windings Lu, Lv, Lw of the motor 42 with each other. In this case, the detection circuit 32 may also measure at least one of the pulse response, resistance value, and inductance of the windings Lu, Lv, Lw of the motor 42 using the power supply lines Pu, Pv, Pw from the drive circuit 31 to the windings Lu, Lv, Lw of the motor 42.

[0109] In a modified example, the drive circuit 31 can be used to supply a pulse voltage to the motor 42. From the state where the semiconductor switch elements U1, U2, V1, V2, W1, W2 are disconnected, the semiconductor switch elements U1, V2 are turned on only for a short time, so that the pulse voltage can be applied to the windings Lu, Lv of the motor 42 via the power supply lines Pu, Pv. From the state where the semiconductor switch elements U1, U2, V1, V2, W1, W2 are disconnected, the semiconductor switch elements V1, W2 are turned on only for a short time, so that the pulse voltage can be applied to the windings Lv, Lw of the motor 42 via the power supply lines Pv, Pw. From the state where the semiconductor switch elements U1, U2, V1, V2, W1, W2 are disconnected, the semiconductor switch elements W1, U2 are turned on only for a short time, so that the pulse voltage can be applied to the windings Lw, Lu of the motor 42 via the power supply lines Pw, Pu.

[0110] In a modified example, the second control mode may also have at least one of a function of stopping the operation of the motor 42 driven by the drive circuit 31 when the temperature of the outside air exceeds the upper limit temperature of the operation in the cooling operation; and a function of stopping the operation of the motor 42 driven by the drive circuit 31 when the temperature of the outside air is lower than the lower limit temperature of the operation in the heating operation. The second control mode may also stop the operation of the motor 42 driven by the drive circuit 31 regardless of the temperature of the outside air. That is, if the detection circuit 32 detects that the insulation of the windings Lu, Lv, and Lw of the motor 42 is degraded, the control circuit 33 may also stop the operation of the motor 42 driven by the drive circuit 31.

[0111] In a modified example, the refrigeration cycle device is not limited to an air conditioner having a structure in which one outdoor unit is connected to one indoor unit (so-called indoor air conditioner (RAC)). The refrigeration cycle device may also be an air conditioner having a structure in which one or more outdoor units are connected to multiple indoor units (so-called cabinet air conditioner (PAC), building multi-split air conditioner (VRF)). Alternatively, the refrigeration cycle device is not limited to an air conditioner, but may also be a freezing or refrigeration device such as a refrigerator or freezer.

[0112] [3. Method]

[0113] As can be seen from the above-mentioned embodiments and variations, the present invention includes the following aspects. In the following, only for the purpose of clarifying the corresponding relationship with the embodiments, the reference numerals are marked in brackets. In addition, in consideration of the readability of the article, the description of the reference numerals in brackets after the second time is sometimes omitted.

[0114] The first embodiment is a refrigeration cycle device (1), comprising: a refrigeration cycle circuit (2) including a compressor (4), a condenser (a first heat exchanger 5, a second heat exchanger 7), an expansion valve (6) and an evaporator (a first heat exchanger 5, a second heat exchanger 7), in 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 ethylene fluoroolefin as a refrigerant component. The compressor (4) comprises: a closed container (40) constituting a flow path of the working medium (20); a compression mechanism (41) located in the closed container (40) and compressing the working medium (20); and a motor (42) located in the closed container (40) and actuating the compression mechanism (41). The control device (3; 3A; 3B) comprises: a driving circuit (31) for driving the motor (42); a detection circuit (32) for detecting insulation degradation of the windings (Lu, Lv, Lw) of the motor (42); and a control circuit (33) having a first control mode for controlling the refrigeration cycle (2) under a first condition; and a second control mode for controlling the refrigeration cycle (2) under a second condition in which 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 the second control mode is selected if insulation degradation of the windings (Lu, Lv, Lw) of the motor (42) is detected in the detection circuit (32). This mode can suppress the disproportionation reaction of the working medium (20).

[0115] The second embodiment is a refrigeration cycle device (1) based on the first embodiment. In this embodiment, before the drive circuit (31) drives the motor (42), the control circuit (33) determines whether the detection circuit (32) detects insulation degradation of the winding (Lu, Lv, Lw) of the motor (42). When the detection circuit (32) does not detect insulation degradation of the winding (Lu, Lv, Lw) of the motor (42), the control circuit (33) executes the first control mode, and when the detection circuit (32) detects insulation degradation of the winding (Lu, Lv, Lw) of the motor (42), the control circuit (33) executes the second control mode. This embodiment can improve the safety of the operation of the refrigeration cycle device (1).

[0116] The third mode is a refrigeration cycle device (1) based on the first or second mode. In this mode, the second control mode controls the refrigeration cycle circuit (2) so that the pressure of the working medium (20) in the compressor (4) becomes less than a specified pressure, and the temperature of the working medium (20) in the compressor becomes less than a specified temperature. The specified pressure and the specified temperature are set so that even if a discharge phenomenon occurs in the winding (Lu, Lv, Lw) of the electric motor (42) in the closed container (40), the disproportionation reaction of the working medium (20) does not develop. This mode can continue the operation of the refrigeration cycle device (1) while suppressing the disproportionation reaction of the working medium (20).

[0117] The 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) for performing heat exchange between outside air and the working medium (20); and a second heat exchanger (7) for performing heat exchange between indoor air and the working medium (20). The control circuit (33) has the function of executing cooling operation and heating operation, the cooling operation controls the refrigeration cycle circuit (2) so that the first heat exchanger (5) functions as the condenser and the second heat exchanger (7) functions as the evaporator, and the heating operation controls the refrigeration cycle circuit (2) 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) driven by the drive circuit (31) when the temperature of the outside air exceeds the upper limit temperature during the cooling operation, or stops the operation of the motor (42) driven by the drive circuit (31) when the temperature of the outside air is lower than the lower limit temperature during the heating operation. This method can improve the safety of the operation of the refrigeration cycle device (1).

[0118] A fifth aspect is a refrigeration cycle device (1) according to any one of the first to fourth aspects. In this aspect, the detection circuit (32) measures a pulse response, at least one of a resistance value and an inductance of a winding (Lu, Lv, Lw) of the motor (42), and detects insulation degradation of the winding (Lu, Lv, Lw) of the motor (42) based on at least one of comparison of an evaluation value of the pulse response, at least one of the resistance value and the inductance of the winding (Lu, Lv, Lw) of the motor (42) with a threshold value, and comparison of evaluation values ​​of the pulse response, at least one of the resistance value and the inductance of a plurality of windings (Lu, Lv, Lw) of the motor (42) with each other. This aspect can improve the detection accuracy of insulation degradation of the winding (Lu, Lv, Lw) of the motor (42).

[0119] A sixth aspect is a refrigeration cycle device (1) based on the fifth aspect. In this aspect, the detection circuit (32) measures at least one of a pulse response, a resistance value, and an inductance of the winding (Lu, Lv, Lw) of the motor (42) by using a power supply line (Pu, Pv, Pw) from the drive circuit (31) to the winding (Lu, Lv, Lw) of the motor (42). This aspect can simplify the structure of the control device.

[0120] A seventh aspect is a refrigeration cycle device (1) based on the sixth aspect. In this aspect, the detection circuit (32) is arranged on the same substrate (34) as the control circuit (33), or constitutes an integrated circuit (35) together with the control circuit (33). This aspect can simplify the structure of the control device.

[0121] The eighth aspect is a refrigeration cycle device (1) according to any one of the first to seventh aspects. In this aspect, the ethylene fluoroolefin includes an ethylene fluoroolefin that undergoes a disproportionation reaction. This aspect can suppress the disproportionation reaction of the working medium (20).

[0122] A ninth aspect is a refrigeration cycle device (1) according to 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 can suppress the disproportionation reaction of the working medium (20).

[0123] A tenth aspect is a refrigeration cycle device (1) according to any one of the first to ninth aspects. In this aspect, the working medium (20) further contains difluoromethane as the refrigerant component. This aspect can suppress the disproportionation reaction of the working medium (20).

[0124] The eleventh aspect is a refrigeration cycle device (1) according to any one of the first to tenth aspects. In this aspect, the working medium (20) further contains saturated hydrocarbons. This aspect can suppress the disproportionation reaction of the working medium (20).

[0125] A twelfth aspect is a refrigeration cycle device (1) according to any one of the first to eleventh aspects. In this aspect, the working medium (20) contains a halogenated alkane having 1 or 2 carbon atoms as a disproportionation inhibitor for inhibiting the disproportionation reaction of the ethylene-based fluoroolefin. This aspect can inhibit the disproportionation reaction of the working medium (20).

[0126] A thirteenth aspect is a refrigeration cycle device (1) according to the eleventh aspect. In this aspect, the saturated hydrocarbon contains n-propane. This aspect can suppress the disproportionation reaction of the working medium (20).

[0127] The second to thirteenth aspects are optional elements and are not essential.

[0128] Industrial Applicability

[0129] The present invention can be applied to a refrigeration cycle device. Specifically, the present invention can be applied to a refrigeration cycle device in which the working medium contains ethylene-based fluoroolefin as a refrigerant component.

[0130] Description of Reference Numerals

[0131] 1 Refrigeration cycle device

[0132] 2 Refrigeration cycle

[0133] 20 Working medium

[0134] 3. 3A, 3B control devices

[0135] 31. Driving circuit

[0136] 32 Detection circuit

[0137] 33 Control circuit

[0138] 34 substrate

[0139] 35 Integrated Circuits

[0140] Pu, Pv, Pw power supply lines

[0141] 4 Compressor

[0142] 40 Sealed container

[0143] 41 Compression mechanism

[0144] 42 Electric Motor

[0145] Lu, Lv, Lw winding

[0146] 51st heat exchanger (condenser, evaporator)

[0147] 6Expansion valve

[0148] 7. Second heat exchanger (condenser, evaporator).

Claims

1. A refrigeration cycle device, characterized in that: include: A refrigeration cycle loop, comprising a compressor, a condenser, an expansion valve and an evaporator, wherein a working medium circulates in the refrigeration cycle loop; and a control device for controlling the refrigeration cycle, The working medium contains ethylene fluoroolefin as a refrigerant component, The compressor comprises: A closed container constituting a flow path of the working medium; a compression mechanism located in the closed container and capable of compressing the working medium; and an electric motor located in the sealed container and capable of actuating the compression mechanism, The control device has: a drive circuit for driving the motor; a detection circuit for detecting insulation degradation of a winding of the motor; and 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 in which at least one of the maximum pressure and the maximum temperature of the working medium in the compressor is lower than the first condition, wherein the second control mode is selected when insulation degradation of the winding of the motor is detected in the detection circuit.

2. The refrigeration cycle device according to claim 1, characterized in that: Before the drive circuit drives the motor, the control circuit determines whether the detection circuit detects insulation degradation of the winding of the motor. The control circuit executing the first control mode when the detection circuit does not detect insulation degradation of the winding of the motor, The second control mode is executed when the detection circuit detects insulation degradation of the winding of the motor.

3. The refrigeration cycle device according to claim 1 or 2, characterized in that: The second control mode controls the refrigeration cycle so that the pressure of the working medium in the compressor becomes lower than a predetermined pressure and the temperature of the working medium in the compressor becomes lower than a predetermined temperature. The predetermined pressure and the predetermined temperature are set so that even when a discharge phenomenon occurs in the winding of the electric motor in the closed container, a disproportionation reaction of the working medium does not progress.

4. The refrigeration cycle device according to claim 1 or 2, characterized in that: The refrigeration cycle includes: a first heat exchanger for performing heat exchange between the outside air and the working medium; and a second heat exchanger for performing heat exchange between the indoor air and the working medium. The control circuit has a function of executing a cooling operation and a heating operation. The cooling operation controls the refrigeration cycle in a manner that the first heat exchanger functions as the condenser and the second heat exchanger functions as the evaporator. The heating operation controls the refrigeration cycle in a manner 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 motor driven by the drive circuit when the temperature of the outside air exceeds the upper limit temperature of operation during the cooling operation, or stops the operation of the motor driven by the drive circuit when the temperature of the outside air is lower than the lower limit temperature of operation during the heating operation.

5. The refrigeration cycle device according to any one of claims 1 to 4, characterized in that: The detection circuit, measuring at least one of a pulse response, a resistance value and an inductance of a winding of the motor, Insulation degradation of the winding of the motor is detected based on at least one of comparison between an evaluation value of a pulse response of the winding of the motor, at least one of a resistance value and an inductance and a threshold value, and comparison between evaluation values ​​of a pulse response of multiple windings of the motor, at least one of a resistance value and an inductance, and each other.

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

7. The refrigeration cycle device according to claim 6, characterized in that: The detection circuit is arranged on the same substrate as the control circuit, or is formed integrally with the control circuit.

8. The refrigeration cycle device according to any one of claims 1 to 7, characterized in that: The ethylene fluoroolefin contains an ethylene fluoroolefin that undergoes a disproportionation reaction.

9. The refrigeration cycle device according to any one of claims 1 to 8, characterized in that: The ethylene-based fluoroolefin is 1,1,2-trifluoroethylene, trans-1,2-difluoroethylene, cis-1,2-difluoroethylene, 1,1-difluoroethylene, tetrafluoroethylene, or monofluoroethylene.

10. The refrigeration cycle device according to any one of claims 1 to 9, characterized in that: The working medium further contains difluoromethane as the refrigerant component.

11. The refrigeration cycle device according to any one of claims 1 to 10, characterized in that: The working medium also contains saturated hydrocarbons.

12. The refrigeration cycle device according to any one of claims 1 to 11, characterized in that: The working medium contains a halogenated alkane having 1 or 2 carbon atoms as a disproportionation inhibitor for inhibiting the disproportionation reaction of the ethylene-based fluoroolefin.

13. The refrigeration cycle device according to claim 11, characterized in that: The saturated hydrocarbons include n-propane.

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