WO2025009431A1 - 制御装置、冷凍サイクル装置、制御方法、プログラム - Google Patents

制御装置、冷凍サイクル装置、制御方法、プログラム Download PDF

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Publication number
WO2025009431A1
WO2025009431A1 PCT/JP2024/022847 JP2024022847W WO2025009431A1 WO 2025009431 A1 WO2025009431 A1 WO 2025009431A1 JP 2024022847 W JP2024022847 W JP 2024022847W WO 2025009431 A1 WO2025009431 A1 WO 2025009431A1
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Prior art keywords
compressor
circuit
refrigeration cycle
voltage
drive circuit
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PCT/JP2024/022847
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English (en)
French (fr)
Japanese (ja)
Inventor
寛規 角山
宣明 長尾
光 村上
晃 鶸田
任彦 橋元
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Panasonic Intellectual Property Management Co Ltd
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Panasonic Intellectual Property Management Co Ltd
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Priority to JP2025531501A priority Critical patent/JPWO2025009431A1/ja
Priority to CN202480045234.XA priority patent/CN121464308A/zh
Publication of WO2025009431A1 publication Critical patent/WO2025009431A1/ja
Priority to US19/423,316 priority patent/US20260110476A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F25B49/022—Compressor control arrangements
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/02—Materials undergoing a change of physical state when used
    • C09K5/04—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
    • F25B43/006—Accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/07—Exceeding a certain pressure value in a refrigeration component or cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/15—Power, e.g. by voltage or current
    • F25B2700/151—Power, e.g. by voltage or current of the compressor motor

Definitions

  • This disclosure relates to a control device, a refrigeration cycle device, a control method, and a program.
  • 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.
  • HFO1123 and HFO1132 have a smaller GWP than R410A, but this makes them less stable than R410A.
  • the generation of radicals can cause disproportionation reactions of HFO1123 or HFO1132, which can cause HFO1123 and HFO1132 to change into different compounds.
  • Patent Document 3 discloses a refrigeration cycle device that aims to improve the reliability of a refrigeration cycle device that uses a working medium containing HFO1123.
  • the refrigeration cycle device disclosed in Patent Document 3 is a refrigeration cycle device that is configured by connecting a compressor equipped with an electric motor, a condenser, an expansion means, and an evaporator in a ring shape to form a refrigeration cycle, and is configured by sealing a working medium containing an ethylene-based fluorohydrocarbon having a double bond in the refrigeration cycle, and is equipped with a protection device that stops the power supply to the compressor when the current value input to the compressor exceeds a predetermined current value that is set to be three times or more the maximum current value during normal operation other than at startup or two times or more the current value at startup.
  • Patent Document 3 states that "When the current value input to the compressor exceeds a predetermined value, the power supply to the motor is stopped, thereby preventing layer shorts caused by overcurrent and effectively suppressing the disproportionation reaction.”
  • the discharge energy that determines the reaction propagation of the disproportionation reaction is highly dependent on the internal pressure of the compressor, and when the internal pressure of the compressor is high, the disproportionation reaction may not be sufficiently suppressed.
  • the present disclosure provides a control device, a refrigeration cycle device, a control method, and a program that enable improved suppression of disproportionation reactions in a working medium.
  • the control device includes a compressor, a condenser, an expansion valve, and an evaporator, and controls a refrigeration cycle circuit in which a working medium circulates.
  • the control device includes a drive circuit that drives the compressor, a state detection circuit that detects the state of at least one of the compressor and the drive circuit, a switching device that can switch between a first path that connects a discharge pipe of the compressor to the condenser and a second path that connects the discharge pipe of the compressor to a specified space that reduces the internal pressure of the compressor to a specified pressure or lower, and a control circuit that controls the drive circuit and the switching device.
  • the control circuit switches the first path to the second path by the switching device when the state of at least one of the compressor and the drive circuit detected by the state detection circuit indicates an unsteady state of the refrigeration cycle circuit.
  • the refrigeration cycle device includes the above-mentioned control device and the above-mentioned refrigeration cycle circuit.
  • the control method is executed by a control device that includes a compressor, a condenser, an expansion valve, and an evaporator, and controls a refrigeration cycle circuit through which a working medium circulates.
  • the control device includes a drive circuit that drives the compressor, and a control circuit that controls the drive circuit.
  • the control method connects the discharge pipe of the compressor to a specified space, thereby reducing the internal pressure of the compressor to a specified pressure or lower.
  • the program according to one aspect of the present disclosure is executed in a computer system equipped with a control device that includes a compressor, a condenser, an expansion valve, and an evaporator, and controls a refrigeration cycle circuit through which a working medium circulates.
  • the control device includes a drive circuit that drives the compressor, and a control circuit that controls the drive circuit.
  • the program instructs the computer system to connect the discharge pipe of the compressor to a specified space and reduce the internal pressure of the compressor to a specified pressure or lower when the state of at least one of the compressor and the drive circuit indicates an unsteady state of the refrigeration cycle circuit.
  • aspects of the present disclosure enable improved suppression of disproportionation reactions in the working medium.
  • FIG. 1 is a schematic diagram of a compressor and a control device of a refrigeration cycle device according to a first embodiment
  • FIG. 1 is a waveform diagram of a voltage of a smoothing circuit of a drive circuit of a control device according to a first embodiment.
  • 1 is a part of a flowchart of the operation of the control device according to the first embodiment.
  • 1 is a part of a flowchart of the operation of the control device according to the first embodiment.
  • 1 is a part of a flowchart of the operation of the control device according to the first embodiment.
  • 1 is a part of a flowchart of the operation of the control device according to the first embodiment.
  • 1 is a part of a flowchart of the operation of the control device according to the first embodiment.
  • Block diagram of a refrigeration cycle device according to a third embodiment. 13 is a flowchart of a first example of the operation of the control device according to the third embodiment. 13 is a part of a flowchart of a second example of the operation of the control device according to the third embodiment. 13 is a part of a flowchart of a second example of the operation of the control device according to the third embodiment.
  • prefixes such as “first” and “second” are added to the names of the components.
  • the prefixes such as “first” and “second” may be omitted in consideration of readability of the text.
  • 1.1 First embodiment 1.1.1 Configuration 1 is a block diagram of a refrigeration cycle apparatus 1 according to the present embodiment.
  • the refrigeration cycle apparatus 1 constitutes, for example, an air conditioner capable of cooling operation and heating operation.
  • the refrigeration cycle apparatus 1 includes a refrigeration cycle circuit 2 and a control device 3.
  • the refrigeration cycle circuit 2 constitutes a flow path through which the working medium 20 (see FIG. 2) circulates.
  • the working medium 20 contains an ethylene-based fluoroolefin as a refrigerant component.
  • the ethylene-based fluoroolefin may be an ethylene-based fluoroolefin that undergoes a disproportionation reaction.
  • Examples of the ethylene-based fluoroolefin that undergoes 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), tetrafluoroethylene (CF 2 ⁇ CF 2 , FO1114), and monofluoroethylene (HFO-1141).
  • the working medium 20 may contain multiple types of refrigerant components.
  • the working medium 20 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.
  • secondary refrigerant components include hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), saturated hydrocarbons, carbon dioxide, etc.
  • hydrofluorocarbons examples include difluoromethane, difluoroethane, trifluoroethane, tetrafluoroethane, pentafluoroethane, pentafluorobutane, heptafluorocyclopentane, etc.
  • hydrofluoroolefins examples include monofluoropropene, trifluoropropene, tetrafluoropropene, pentafluoropropene, hexafluorobutene, etc.
  • saturated hydrocarbons examples include ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methylpropane), methylcyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2,2-dimethylpropane), methylcyclobutane, etc.
  • the working fluid 20 may further include a disproportionation inhibitor that suppresses the disproportionation reaction of the ethylene-based fluoroolefin.
  • the disproportionation inhibitor include saturated hydrocarbons or haloalkanes.
  • 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.
  • n-propane is preferred.
  • haloalkanes examples include haloalkanes having 1 or 2 carbon atoms.
  • haloalkanes having one carbon atom examples 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) ,
  • haloalkanes having 2 carbon atoms examples 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 ), etc.
  • the working fluid 20 may contain one or more types of haloalkanes having 1 or 2 carbon atoms. In other words, 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.
  • a pressure sensor (GC61 manufactured by Nagano Keiki Co., Ltd.) for measuring the internal pressure in the pressure-resistant vessel (stainless steel sealed vessel, internal volume 50 mL), a thermocouple (PL thermocouple ground PL-18-K-A 4-T manufactured by Conax Technologies) for measuring the internal temperature in the pressure-resistant vessel, and a discharge device for generating a discharge in the pressure-resistant vessel were attached to the sealed pressure-resistant vessel (stainless steel sealed vessel, internal volume 50 mL).
  • a pressure sensor GC61 manufactured by Nagano Keiki Co., Ltd.
  • PL thermocouple ground PL-18-K-A 4-T manufactured by Conax Technologies
  • a gas cylinder of 1,1,2-trifluoroethylene was connected so that the pressure could be adjusted.
  • a mantle heater was installed to heat the entire pressure-resistant vessel, and a ribbon heater (flexible ribbon heater 1 m, 200 W manufactured by Tokyo Institute of Technology Co., Ltd.) was installed to heat the piping part as well. In this way, an experimental system for the disproportionation reaction was constructed.
  • Table 1 below shows whether or not a disproportionation reaction occurs when 1,1,2-trifluoroethylene is used as the working medium 20.
  • the temperature [°C] in Table 1 is the internal temperature inside the pressure vessel.
  • the pressure [MPa] in Table 1 is the internal pressure inside the pressure vessel.
  • the stored energy [J] in Table 1 is the electrostatic energy stored in the capacitor section installed inside the discharge device.
  • the number of consecutive discharges is the number of consecutive discharges at regular intervals under the conditions in question. If a disproportionation reaction occurs after that number of discharges, the disproportionation reaction is recorded as "Yes", and if no disproportionation reaction is observed, it is recorded as "No".
  • the refrigeration cycle circuit 2 includes a compressor 4, a first heat exchanger 5, an expansion valve 6, a second heat exchanger 7, a four-way valve 8, and an accumulator 9.
  • 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 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 indoor unit 1b further includes a second blower 7a for promoting heat exchange in the second heat exchanger 7.
  • the compressor 4 compresses the working medium 20 to increase the pressure of the working medium 20.
  • 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 20 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 20 and the flow rate of the working medium 20.
  • the four-way valve 8 switches the direction of the working medium 20 circulating through the refrigeration cycle circuit 2 between a first direction corresponding to cooling operation and a second direction corresponding to heating operation.
  • the first direction is the direction in which the working medium 20 circulates through the refrigeration cycle circuit 2 in the order of the compressor 4, four-way valve 8, first heat exchanger 5, expansion valve 6, second heat exchanger 7, four-way valve 8, and accumulator 9, as shown by the solid arrow A1 in Figure 1.
  • the compressor 4 compresses and discharges the gaseous working medium 20, 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 20, causing the gaseous working medium 20 to condense and become liquefied.
  • the liquid working medium 20 is decompressed by the expansion valve 6 and sent to the second heat exchanger 7.
  • heat exchange occurs between the liquid working medium 20 and the indoor air, causing the gaseous working medium 20 to evaporate and become the gaseous working medium 20.
  • the gaseous working medium 20 returns to the compressor 4 via the four-way valve 8.
  • the first heat exchanger 5 functions as a condenser
  • 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.
  • the second direction is the direction in which the working medium 20 circulates through the refrigeration cycle circuit 2 in the order of the compressor 4, four-way valve 8, second heat exchanger 7, expansion valve 6, first heat exchanger 5, and accumulator 9, as shown by dashed arrow A2 in Figure 1.
  • the compressor 4 compresses and discharges the gaseous working medium 20, 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 indoor air and the gaseous working medium 20, and the gaseous working medium 20 condenses and becomes liquefied.
  • the liquid working medium 20 is decompressed by the expansion valve 6 and sent to the first heat exchanger 5.
  • heat exchange is performed between the liquid working medium 20 and the outside air, and the gaseous working medium 20 evaporates and becomes the gaseous working medium 20.
  • the gaseous working medium 20 returns to the compressor 4 via the four-way valve 8.
  • the first heat exchanger 5 functions as an evaporator
  • the second heat exchanger 7 functions as a condenser. Therefore, during heating, the indoor unit 1b blows air warmed by heat exchange in the second heat exchanger 7 into the room.
  • Figure 2 is a schematic diagram of the compressor 4 and the control device 3.
  • the compressor 4 is, for example, a hermetic compressor.
  • the compressor 4 may be of a rotary type, a scroll type, or any other known type.
  • the compressor 4 includes a hermetic container 40, a compression mechanism 41, and an electric motor 42.
  • the sealed container 40 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 sucked 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 high-temperature, high-pressure working medium 20 and lubricating oil.
  • the bottom of the sealed container 40 forms an oil storage section that stores a mixture of the working medium 20 and lubricating oil.
  • 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 connected to the rolling piston.
  • the electric motor 42 is located inside the sealed container 40 and operates the compression mechanism 41.
  • the electric motor 42 is, for example, a brushless motor (three-phase brushless motor).
  • the electric motor 42 includes, for example, a rotor fixed to the crankshaft of the compression mechanism 41 and a stator provided around the rotor.
  • the stator is, for example, configured by concentrating or dispersing a stator winding (magnet wire, etc.) around a stator core (electromagnetic steel plate, etc.) with an insulating material such as insulating paper interposed between the stator winding.
  • the stator winding is covered with an insulating material. Examples of insulating materials include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), aramid polymer, polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), etc.
  • the accumulator 9 is provided to prevent liquid compression in the compression chamber of the compression mechanism 41.
  • the accumulator 9 is located on the suction pipe 401 side of the compressor 4. More specifically, the accumulator 9 is located between the suction pipe 401 of the compressor 4 and the four-way valve 8.
  • the accumulator 9 separates the working medium 20 into a gaseous working medium 20 and a liquid working medium 20, and guides only the gaseous working medium 20 from the suction pipe 401 to the inside of the sealed container 40.
  • the control device 3 controls the compressor 4 of the refrigeration cycle circuit 2.
  • the control device 3 includes a drive circuit 31, a state detection circuit 32, a first protection device 33, a second protection device 34, a control circuit 35, and a switching device 36.
  • the switching device 36 will be described with reference to FIG. 1.
  • the switching device 36 constitutes a part of the refrigeration cycle circuit 2.
  • the switching device 36 can switch between the first route R1 and the second route R2.
  • the switching device 36 is a four-way valve.
  • the switching device 36 is located between the compressor 4 and the four-way valve 8.
  • the switching device 36 is connected by the four-way valve 8 to the first heat exchanger 5 during cooling operation and to the second heat exchanger 7 during heating operation.
  • the first heat exchanger 5 during cooling operation and the second heat exchanger 7 during heating operation are both condensers.
  • the switching device 36 is located between the compressor 4 and the condenser.
  • the first path R1 connects the discharge pipe 402 of the compressor 4 to the first heat exchanger 5 during cooling operation and to the second heat exchanger 7 during heating operation. That is, the first path R1 connects the discharge pipe 402 of the compressor 4 to the condenser. Furthermore, the first path R1 connects the second heat exchanger 7 to the accumulator 9 during cooling operation and the first heat exchanger 5 to the accumulator 9 during heating operation. The second heat exchanger 7 during cooling operation and the first heat exchanger 5 during heating operation are both evaporators. Therefore, the first path R1 connects the evaporator to the accumulator 9. In the first path R1, the path connecting the discharge pipe 402 of the compressor 4 to the condenser and the path connecting the evaporator to the accumulator 9 are independent of each other.
  • the second path R2 connects the discharge pipe 402 of the compressor 4 to a predetermined space.
  • the predetermined space is set so that the internal pressure of the compressor 4 can be reduced to or below a predetermined pressure.
  • the predetermined pressure is set to a pressure at which substantially no heat exchange occurs in the first heat exchanger 5 or the second heat exchanger 7 during heating operation.
  • the predetermined space is a space with a pressure of 0.4 MPa or less.
  • the predetermined pressure is, for example, 3.0 MPa or less.
  • the predetermined space is inside the refrigeration cycle circuit 2.
  • the predetermined space is the internal space of the accumulator 9.
  • the second path R2 connects the discharge pipe 402 of the compressor 4 to the accumulator 9.
  • the discharge pipe 402 of the compressor 4 is connected to the suction pipe 401 of the compressor 4 via the accumulator 9. Furthermore, the second path R2 connects the evaporator to the condenser via the four-way valve 8. In the second route R2, the route connecting the discharge pipe 402 of the compressor 4 to the accumulator 9 and the route connecting the evaporator to the condenser are independent of each other.
  • the switching device 36 constitutes a pressure control mechanism that reduces the internal pressure of the compressor 4 below a predetermined value by switching the connection of the discharge pipe 402 of the compressor 4 from the condenser to a predetermined space.
  • the drive circuit 31 drives the electric motor 42 based on the input power from the power source 10.
  • the power source 10 is an AC power source
  • the input power is AC power.
  • the drive circuit 31 includes a converter circuit 311 and an inverter circuit 312.
  • the converter circuit 311 outputs DC output power based on the input power from the power source 10 so that the voltage becomes a first voltage. In other words, the converter circuit 311 converts the input power into DC output power so that the voltage of the DC output power becomes the first voltage.
  • the first voltage corresponds to the rated voltage of the drive circuit 31.
  • 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 source 10 is connected between the input terminals of the rectifier circuit 311a (the connection point of diodes D1, D2, and the connection point of diodes D3, D4), and the smoothing circuit 311b is connected between the output terminals of the rectifier circuit 311a (the connection point of diodes D1, D3, and the connection point of diodes D2, D4).
  • the smoothing circuit 311b smoothes and outputs the voltage between the output terminals of the rectifier circuit 311a.
  • the smoothing circuit 311b sets the voltage of the DC output power to a first voltage.
  • the smoothing circuit 311b includes a series circuit of an inductor L1 and smoothing capacitors C1 and C2.
  • the connection point between the inductor L1 and the smoothing capacitor C1 is the first output point P1 that outputs a voltage corresponding to the first voltage.
  • the connection point between the connection point of the diodes D2 and D4 and the smoothing capacitor C2 is the second output point P2 that outputs a voltage lower than the voltage at the first output point P1.
  • the connection point between the smoothing capacitor C1 and the smoothing capacitor C2 is the third output point P3 that outputs a voltage between the voltage at the first output point P1 and the voltage at the second output point P2.
  • the first output point P1 is a high voltage point
  • the second output point P2 is a low voltage point
  • the third output point P3 is an intermediate voltage point.
  • the smoothing capacitors C1 and C2 have the same capacitance.
  • the voltage between the voltage at the first output point P1 and the voltage at the third output point P3 is equal to the voltage between the voltage at the second output point P2 and the voltage at the third output point P3. If the voltage between the first output point P1 and the second output point P2 (which corresponds to the first voltage) is E, the voltage between the first output point P1 and the third output point P3 is E/2, and similarly, the voltage between the second output point P2 and the third output point P3 is E/2. This allows the drive circuit 31 to provide five levels of voltage: E, E/2, 0, -E/2, and -E.
  • the inverter circuit 312 outputs AC output power to the motor 42 based on the DC output power from the converter circuit 311.
  • the AC output power is three-phase AC power.
  • the inverter circuit 312 includes a plurality of semiconductor switching elements U1 to U4, V1 to V4, and W1 to W4.
  • the semiconductor switching elements U1 to U4, V1 to V4, and W1 to W4 are, for example, transistors.
  • the semiconductor switching elements U1 to U4, V1 to V4, and W1 to W4 each form a series circuit and are connected between the first output point P1 and the second output point P2.
  • connection point of the semiconductor switching elements U1 and U2, the connection point of the semiconductor switching elements V1 and V2, and the connection point of the semiconductor switching elements W1 and W2 are connected to the third output point P3 via diodes D5, D7, and D9, respectively.
  • the anodes of diodes D5, D7, and D9 are connected to the third output point P3, and the cathodes of diodes D5, D7, and D9 are connected to the connection point of semiconductor switching elements U1 and U2, the connection point of semiconductor switching elements V1 and V2, and the connection point of semiconductor switching elements W1 and W2, respectively.
  • connection point of the semiconductor switching elements U2, U3 constitutes the U-phase output terminal Pu, which is connected to the U-phase input terminal of the motor 42.
  • the connection point of the semiconductor switching elements V2, V3 constitutes the V-phase output terminal Pv, which is connected to the V-phase input terminal of the motor 42.
  • the connection point of the semiconductor switching elements W2, W3 constitutes the W-phase output terminal Pw, which is connected to the W-phase input terminal of the motor 42.
  • connection point of the semiconductor switching elements U3 and U4, the connection point of the semiconductor switching elements V3 and V4, and the connection point of the semiconductor switching elements W3 and W4 are connected to the third output point P3 via diodes D6, D8, and D10, respectively.
  • the cathodes of diodes D6, D8, and D10 are connected to the third output point P3, and the anodes of diodes D6, D8, and D10 are connected to the connection point of semiconductor switching elements U3 and U4, the connection point of semiconductor switching elements V3 and V4, and the connection point of semiconductor switching elements W3 and W4, respectively.
  • the semiconductor switching elements U1, U2, V1, V2, W1, and W2 constitute a first semiconductor switching element group connected between the first output point P1 and the motor 42.
  • the semiconductor switching elements U1 and U2 constitute a U-phase first semiconductor switching element group connected between the first output point P1 and the U-phase input terminal of the motor 42.
  • the semiconductor switching elements V1 and V2 constitute a V-phase first semiconductor switching element group connected between the first output point P1 and the V-phase input terminal of the motor 42.
  • the semiconductor switching elements W1 and W2 constitute a W-phase first semiconductor switching element group connected between the first output point P1 and the W-phase input terminal of the motor 42.
  • the semiconductor switching elements U3, U4, V3, V4, W3, and W4 constitute a second semiconductor switching element group connected between the second output point P2 and the motor 42.
  • the semiconductor switching elements U3 and U4 constitute a U-phase second semiconductor switching element group connected between the second output point P2 and the U-phase input terminal of the motor 42.
  • the semiconductor switching elements V3 and V4 constitute a V-phase second semiconductor switching element group connected between the second output point P2 and the V-phase input terminal of the motor 42.
  • the semiconductor switching elements W3 and W4 constitute a W-phase second semiconductor switching element group connected between the second output point P2 and the W-phase input terminal of the motor 42.
  • the semiconductor switching elements U2, U3, V2, V3, W2, and W3 constitute a second semiconductor switching element group connected between the second output point P2 and the motor 42.
  • the semiconductor switching elements U2 and U3 constitute a U-phase third semiconductor switching element group connected between the third output point P3 and the U-phase input terminal of the motor 42.
  • the semiconductor switching elements V2 and V3 constitute a V-phase third semiconductor switching element group connected between the third output point P3 and the V-phase input terminal of the motor 42.
  • the semiconductor switching elements W2 and W3 constitute a W-phase third semiconductor switching element group connected between the third output point P3 and the W-phase input terminal of the motor 42.
  • the converter circuit 311 has a plurality of output points including the first to third output points P1 to P3.
  • the inverter circuit 312 has a plurality of semiconductor switching element groups including a first semiconductor switching element group (semiconductor switching elements U1, U2, V1, V2, W1, W2) connected between the first output point P1 and the motor 42, a second semiconductor switching element group (semiconductor switching elements U3, U4, V3, V4, W3, W4) connected between the second output point P2 and the motor 42, and a third semiconductor switching element group (semiconductor switching elements U2, U3, V2, V3, W2, W3) connected between the third output point P3 and the motor 42.
  • the drive circuit 31 is a so-called multilevel inverter, in particular a three-level inverter.
  • the state detection circuit 32 detects the state of at least one of the compressor 4 and the drive circuit 31. In this embodiment, the state detection circuit 32 detects the state of the drive circuit 31.
  • the state of the drive circuit 31 is the voltage of the DC output power of the converter circuit 311.
  • the state detection circuit 32 is a voltage detector that detects the DC output power of the converter circuit 311 and outputs a detection voltage indicating the voltage of the DC output power.
  • the state detection circuit 32 includes a voltage divider circuit connected between the output terminals of the smoothing circuit 311b of the converter circuit 311, that is, between the first output point P1 and the second output point P2, and outputs a detection voltage based on the voltage obtained from the voltage divider circuit.
  • the state detection circuit 32 may also output a detection voltage based on the output of the voltage divider circuit and the differential amplifier.
  • the non-inverting input terminal and the inverting input terminal of the differential amplifier are connected to both ends of the resistor of the voltage divider circuit, respectively, and the differential amplifier can output the voltage across the resistor as a detection voltage.
  • the differential amplifier can output the voltage across the resistor as a detection voltage.
  • the position where the state detection circuit 32 is connected to the drive circuit 31 is not particularly limited, and may be any position where the DC output power of the converter circuit 311 can be detected.
  • the position where the DC output power of the converter circuit 311 can be detected is not limited to within the converter circuit 311, but may be a position within the inverter circuit 312 that is equivalent in circuit terms to each of the first output point P1 and the second output point P2.
  • the voltage divider circuit can adopt a conventionally known configuration, so a detailed description will be omitted.
  • the first protection device 33 is provided to stop the output of AC output power.
  • the first protection device 33 includes switches Su, Sv, and Sw interposed between the drive circuit 31 and the motor 42.
  • the switches Su, Sv, and Sw are connected between the U-phase, V-phase, and W-phase input terminals of the motor 42 and the U-phase output terminals Pu, Pv, and Pw, respectively.
  • the switches Su, Sv, and Sw may be controllable switches such as semiconductor switches and electromagnetic relays.
  • the first protection device 33 In the on state where the switches Su, Sv, and Sw are closed, the first protection device 33 enables the output of AC output power from the drive circuit 31 to the motor 42, and in the off state where the switches Su, Sv, and Sw are open, the first protection device 33 stops the output of AC output power from the drive circuit 31 to the motor 42.
  • the second protection device 34 is provided to stop the input of input power.
  • the second protection device 34 has switches S1 and S2 interposed between the drive circuit 31 and the power source 10.
  • the switches S1 and S2 are respectively connected between the input terminal of the rectifier circuit 311a and the power source 10.
  • the switches S1 and S2 may be, for example, a controllable switch such as a semiconductor switch or an electromagnetic relay.
  • the control circuit 35 may be realized by, for example, a computer system including at least one processor (microprocessor) and one or more memories.
  • the computer system may include one or more A/D converters.
  • the one or more A/D converters are used to convert the detection voltage from the state detection circuit 32 from analog to digital format.
  • the control circuit 35 controls the drive circuit 31, the first protection device 33, the second protection device 34, and the switching device 36.
  • the control circuit 35 executes PWM control of a group of multiple semiconductor switching elements of the inverter circuit 312 of the drive circuit 31 so that the drive circuit 31 operates the electric motor 42.
  • control circuit 35 controls the switching of the multiple semiconductor switching elements U1 to U4, V1 to V4, and W1 to W4 of the inverter circuit 312 of the drive circuit 31 so that the inverter circuit 312 supplies AC output power (three-phase AC power) to the electric motor 42 based on the DC output power from the smoothing circuit 311b.
  • the semiconductor switching elements U1 to U4 have a first state in which the semiconductor switching elements U1 and U2 are on and the semiconductor switching elements U3 and U4 are off, a second state in which the semiconductor switching elements U3 and U4 are on and the semiconductor switching elements U1 and U2 are off, and a third state in which the semiconductor switching elements U2 and U3 are on and the semiconductor switching elements U1 and U4 are off.
  • the voltage at the U-phase output terminal Pu is E/2 in the first state, -E/2 in the second state, and 0 in the third state.
  • the semiconductor switching elements V1 to V4 There are three states for the semiconductor switching elements V1 to V4: a first state in which the semiconductor switching elements V1 and V2 are on and the semiconductor switching elements V3 and V4 are off; a second state in which the semiconductor switching elements V3 and V4 are on and the semiconductor switching elements V1 and V2 are off; and a third state in which the semiconductor switching elements V2 and V3 are on and the semiconductor switching elements V1 and V4 are off.
  • the voltage at the V-phase output terminal Pv is E/2 in the first state, -E/2 in the second state, and 0 in the third state.
  • the semiconductor switching elements W1 to W4 have a first state in which the semiconductor switching elements W1 and W2 are on and the semiconductor switching elements W3 and W4 are off, a second state in which the semiconductor switching elements W3 and W4 are on and the semiconductor switching elements W1 and W2 are off, and a third state in which the semiconductor switching elements W2 and W3 are on and the semiconductor switching elements W1 and W4 are off.
  • the voltage at the W-phase output terminal Pw is E/2 in the first state, -E/2 in the second state, and 0 in the third state.
  • the drive circuit 31 can provide five voltage levels: E, E/2, 0, -E/2, and -E.
  • the control circuit 35 controls the switching of the semiconductor switching elements U1-U4, V1-V4, W1-W4 of the inverter circuit 312 of the drive circuit 31 based on, for example, U-phase, V-phase, and W-phase output voltage command values corresponding to the sine wave AC voltages of the U-phase, V-phase, and W-phase of the three-phase AC, respectively, and the first and second carrier triangular waves.
  • the value of the first carrier triangular wave is 0 or more, and the value of the second carrier triangular wave is 0 or less.
  • the drive circuit 31 can provide five levels of voltage: E, E/2, 0, -E/2, and -E, so that the voltage between the U-phase input terminal and the V-phase input terminal of the motor 42, the voltage between the V-phase input terminal and the W-phase input terminal of the motor 42, and the voltage between the W-phase input terminal and the U-phase input terminal of the motor 42 can each be made closer to a sine wave.
  • the control circuit 35 executes processing to suppress a disproportionation reaction of the working medium 20 circulating through the refrigeration cycle circuit 2 when the state of at least one of the compressor 4 and the drive circuit 31 detected by the state detection circuit 32 indicates an unsteady state of the refrigeration cycle circuit 2.
  • the unsteady state of the refrigeration cycle circuit 2 may include, for example, an abnormality in at least one of the compressor 4 and the drive circuit 31, a state in which a discharge phenomenon that may cause a disproportionation reaction of the working medium 20 circulating through the refrigeration cycle circuit 2 has occurred or may occur, or a state in which a disproportionation reaction of the working medium 20 circulating through the refrigeration cycle circuit 2 is progressing or may progress.
  • control circuit 35 further executes processing to suppress the disproportionation reaction of the working medium 20 circulating through the refrigeration cycle circuit 2 based on the detected voltage from the state detection circuit 32.
  • the causes of the disproportionation reaction of the working medium 20 are thought to be heat and radicals. For example, when radicals are generated under high temperature and pressure, the disproportionation reaction of the working medium 20 is thought to proceed. Radicals may be generated, for example, by a discharge phenomenon that may occur when some abnormality occurs in the compressor 4 or the drive circuit 31.
  • FIG. 3 is a waveform diagram of the voltage of the DC output power of the converter circuit 311.
  • the voltage of the DC output current gradually decreases at times t11 to t12, t21 to t22, t31 to t32, t41 to t42, and t51 to 52, but this voltage decrease is due to the switching of the semiconductor switching elements U1 to U4, V1 to V4, and W1 to W4 of the inverter circuit 312.
  • the switching frequency of the inverter circuit 312 is, for example, 1.0 kHz to 5.0 kHz
  • the time between time t11 and time t21 is about 0.2 to 1.0 ms.
  • a sudden drop in the voltage of the DC output current is observed, which is thought to be due to the occurrence of a discharge phenomenon.
  • control circuit 35 determines whether a discharge phenomenon has occurred based on the detected voltage from the state detection circuit 32, and if it determines that a discharge phenomenon has occurred, it switches from the first route R1 to the second route R2 using the switching device 36 to suppress the disproportionation reaction of the working medium 20 circulating in the refrigeration cycle circuit 2.
  • the control device 3 detects the signs of a disproportionation reaction based on the changes occurring in the DC output power (voltage of the smoothing circuit 311b) inside the drive circuit 31, not on the changes occurring in the current actually flowing from the drive circuit 31 to the motor 42.
  • the time scale of the discharge phenomenon is shorter than the time scale of smoothing (rectification) in the drive circuit 31.
  • the time scale of the discharge phenomenon is on the order of ⁇ s. Therefore, it is possible to determine whether a discharge phenomenon is occurring based on the DC output power inside the drive circuit 31.
  • the measurement of the DC output power (voltage of the smoothing circuit 311b) inside the drive circuit 31 can be performed in a shorter time and at a shorter cycle than the measurement of the current actually flowing from the drive circuit 31 to the motor 42. This enables the earlier detection of the signs of a disproportionation reaction of the working medium 20. If the signs of a disproportionation reaction of the working medium 20 can be detected earlier in this way, the disproportionation reaction can be suppressed earlier, thereby improving the suppression of the disproportionation reaction.
  • the control circuit 35 switches from the first path R1 to the second path R2 by the switching device 36 when the detected voltage falls below a second voltage that is equal to or lower than the first voltage.
  • the second voltage is set to determine whether or not a discharge phenomenon has occurred, which may occur when some abnormality occurs in the compressor 4 or the drive circuit 31.
  • the normal voltage (first voltage) of the DC output current is E
  • the second voltage is 0.3 times or more and 0.8 times or less of the first voltage.
  • the second voltage is 0.8 times the first voltage.
  • the control circuit 35 reduces the internal pressure of the compressor 4 to a predetermined pressure or lower by switching from the first route R1 to the second route R2 using the switching device 36.
  • the reduction in the internal pressure of the compressor 4 increases the discharge energy required for the disproportionation reaction to proceed, making it possible to improve the suppression of the disproportionation reaction.
  • a disproportionation reaction triggered by discharge there is an induction period between the occurrence of the discharge and the rapid reaction propagation, but a disproportionation inhibitor can lengthen the induction period to, for example, about several seconds.
  • the working medium 20 contains a disproportionation inhibitor, the possibility that the disproportionation reaction will proceed before the control circuit 35 reduces the internal pressure of the compressor 4, and the reduction in the internal pressure of the compressor 4 and the long induction period can more effectively suppress the disproportionation reaction of the working medium 20.
  • the control circuit 35 stops or limits the operation of the drive circuit 31 in addition to switching from the first path R1 to the second path R2 by the switching device 36.
  • the operation of the drive circuit 31 can be stopped by either stopping the output of AC output power, stopping the output of DC output power, or stopping the input of input power.
  • the operation of the drive circuit 31 can be restricted by lowering the set value of the amplitude of the AC output power, or lowering the set value of the frequency of the AC output power.
  • control circuit 35 sets the first protection device 33 to the OFF state to electrically isolate the electric motor 42 from the drive circuit 31 and stop the output of AC output power.
  • the control circuit 35 sets the first protection device 33 to the ON state to connect the electric motor 42 to the drive circuit 31.
  • the control circuit 35 controls the drive circuit 31 to lower the set value of the amplitude of the AC output power.
  • the drive circuit 31 can provide five levels of voltage: E, E/2, 0, -E/2, and -E, so the set value of the amplitude of the AC output power is changed from E to E/2.
  • the rotation speed of the motor 42 is lower than when the set value of the amplitude of the AC output power is E.
  • control circuit 35 sets the second protection device 34 to the OFF state to electrically isolate the power source 10 from the drive circuit 31 and stop the output of AC output power.
  • the control circuit 35 sets the second protection device 34 to the ON state to connect the power source 10 to the drive circuit 31.
  • the control circuit 35 stops or limits the operation of the drive circuit 31 in different ways depending on the number of times the detected voltage falls below the second voltage.
  • the control circuit 35 executes processing that suppresses the disproportionation reaction to a higher degree as the number of times the detected voltage falls below the second voltage increases. This enables the control device 3 to suppress the disproportionation reaction even when relatively minor discharge phenomena occur consecutively within a short period of time. For example, it is possible to prevent disproportionation reactions from being induced beyond a predetermined energy due to consecutive occurrences of low-energy abnormal states (discharges), thereby improving the safety of using the working medium 20.
  • the control circuit 35 stops or limits the operation of the drive circuit 31 in different ways depending on the time difference between the first time when the detected voltage first becomes less than the second voltage and the second time when the detected voltage next becomes less than the second voltage.
  • the control circuit 35 executes processing that suppresses the disproportionation reaction to a higher degree the shorter the time difference. This enables the control device 3 to suppress the disproportionation reaction even when relatively minor discharge phenomena occur consecutively within a short period of time. This prevents, for example, a disproportionation reaction from being induced beyond a predetermined energy due to consecutive occurrences of low-energy abnormal states (discharges), improving the safety of using the working medium 20.
  • the process for suppressing the disproportionation reaction includes, for example, the first process to the third process.
  • the first process is a process for stopping the output of AC output power and resuming the output of AC output power after a standby time has elapsed.
  • the second process is a process for stopping the output of AC output power and operating with a lower set value of the amplitude of the AC output power after a standby time has elapsed.
  • the third process is a process for stopping the output of AC output power and stopping the input of input power.
  • the degree of suppression of the disproportionation reaction increases in the order of the third process, the second process, and the first process. In the first or second process, the longer the standby time, the higher the degree of suppression of the disproportionation reaction.
  • the control circuit 35 outputs AC output power to the motor 42 based on the input power of the power source 10 via the drive circuit 31 to drive the compressor 4.
  • the control circuit 35 sets the number of abnormalities to 0 (S10).
  • the number of abnormalities indicates the number of times the detected voltage is less than the second voltage.
  • the number of abnormalities is an indicator of the likelihood of a disproportionation reaction occurring.
  • the control circuit 35 acquires the detection voltage from the state detection circuit 32 (S11). The control circuit 35 determines whether the detection voltage is less than the second voltage (S12).
  • the control circuit 35 determines whether the detected voltage is less than the second voltage at a predetermined period. It is preferable that the predetermined period here is shorter than the period corresponding to the reference frequency of the inverter circuit 312 (e.g., 1000 to 5000 Hz).
  • step S12 if the detected voltage is less than the second voltage (S12: YES), the control circuit 35 switches from the first route R1 to the second route R2 by the switching device 36 (S13). As a result, the control circuit 35 reduces the internal pressure of the compressor 4 to a predetermined pressure or lower. The reduction in the internal pressure of the compressor 4 increases the discharge energy required for the disproportionation reaction to proceed, so the disproportionation reaction is suppressed. Furthermore, the control circuit 35 adds 1 to the number of abnormalities (S14) and determines whether the number of abnormalities is 1 or less (S15).
  • step S15 if the number of abnormalities is 1 or less (S15: YES), the control circuit 35 sets the first protection device 33 to the OFF state to stop the output of the AC output power (S16).
  • the control circuit 35 determines whether a first standby time has elapsed since the output of the AC output power was stopped (S17).
  • the first standby time is, for example, 1 s.
  • the control circuit 35 sets the first protection device 33 to the ON state to resume the output of the AC output power (S18), switches the switching device 36 from the second route R2 to the first route R1, and resumes the operation of the compressor 4 (S19). After that, the process returns to step S11.
  • the control circuit 35 switches from the first path R1 to the second path R2 using the switching device 36 to reduce the internal pressure of the compressor 4 to a predetermined pressure or lower. Furthermore, the control circuit 35 stops the output of the AC output power. The control circuit 35 resumes the output of the AC output power when the first standby time has elapsed since the output of the AC output power was stopped.
  • step S15 if the number of abnormalities is not 1 or less (S15: NO), referring to FIG. 5, the control circuit 35 determines whether the time difference between the first time when the detected voltage first becomes less than the second voltage and the second time when the detected voltage next becomes less than the second voltage is within a first predetermined time (step S20).
  • the shortness of the time difference is an indicator of the likelihood of a disproportionation reaction occurring.
  • the first predetermined time is, for example, about 100 times the period corresponding to the reference frequency of the inverter circuit 312, and is about 20 to 100 ms.
  • step S20 if the time difference is within the first predetermined time (step S20: YES), the control circuit 35 sets the first protection device 33 to the OFF state to stop the output of AC output power (S21). The control circuit 35 sets the second protection device 34 to the OFF state to stop the input of input power (S22). The control circuit 35 outputs a first abnormality notification (S23).
  • the first abnormality notification indicates that an abnormality has occurred in the refrigeration cycle device 1 that is highly likely to cause a disproportionation reaction.
  • the first abnormality notification is output to, for example, the control circuit of the indoor unit 1b and a remote controller. After this, the control circuit 35 stops the operation of the compressor 4 (S24).
  • the control circuit 35 stops the output of the AC output power (S21) and stops the input of the input power (S22).
  • step S20 determines whether the time difference is within a second predetermined time that is longer than the first predetermined time (step S25).
  • the second predetermined time is, for example, about 1000 times the period corresponding to the reference frequency of the inverter circuit 312, and is about 200 ms to 1 s.
  • step S25 if the time difference is within the second predetermined time (step S25: YES), the control circuit 35 sets the first protection device 33 to the off state to stop the output of the AC output power (S26).
  • the control circuit 35 changes the switching control of the semiconductor switching element of the drive circuit 31 so that the set value of the amplitude of the AC output power decreases from E to E/2 (S27).
  • the control circuit 35 outputs a second abnormality notification (S28).
  • the second abnormality notification indicates that an abnormality that is likely to cause a disproportionation reaction has occurred in the refrigeration cycle device 1.
  • the second abnormality notification is output to, for example, the control circuit and remote controller of the indoor unit 1b.
  • the control circuit 35 determines whether a fourth waiting time has elapsed since the output of the AC output power was stopped (S29).
  • the fourth waiting time is longer than the first waiting time.
  • the fourth waiting time is, for example, 60 seconds.
  • the control circuit 35 sets the first protection device 33 to an ON state to resume the output of the AC output power (S30), switches the switching device 36 from the second path R2 to the first path R1, and resumes the operation of the compressor 4 (S31). In this case, the set value of the amplitude of the AC output power remains lowered from E to E/2.
  • the control circuit 35 stops the output of the AC output power (S26) and reduces the set value of the amplitude of the AC output power (S27). If a fourth standby time, which is longer than the first standby time, has elapsed since the output of the AC output power was stopped, the control circuit 35 resumes the output of the AC output power while keeping the set value of the amplitude of the AC output power reduced (S30).
  • control circuit 35 acquires the detection voltage from the state detection circuit 32 (S32). The control circuit 35 determines whether the detection voltage is less than the second voltage (S33).
  • step S33 if the detected voltage is less than the second voltage (S33: YES), the control circuit 35 switches from the first path R1 to the second path R2 by the switching device 36 (S34) and proceeds to step S20 in FIG. 5.
  • step S33 if the detected voltage is not less than the second voltage (S33: NO), the control circuit 35 determines whether the second monitoring time has elapsed since the compressor 4 restarted operating (S35).
  • step S35 if the second monitoring time has elapsed since the compressor 4 restarted operating (S35: YES), the control circuit 35 cancels the reduction in the set value of the amplitude of the AC output power, returns the set value of the amplitude of the AC output power to E (S36), and proceeds to step S11 in FIG. 4.
  • step S35 if the second monitoring time has not elapsed since the compressor 4 restarted operating (S35: NO), the process returns to step S32.
  • steps S32 to S34 if the detected voltage falls below the second voltage between the time when compressor 4 restarts operation and the time when the second monitoring time has elapsed, the process proceeds to step S21 in FIG. 5, and if the detected voltage does not fall below the second voltage between the time when compressor 4 restarts operation and the time when the second monitoring time has elapsed, the process proceeds to step S36.
  • the control circuit 35 cancels the reduction in the set value of the amplitude of the AC output power (S36). If the detected voltage becomes less than the second voltage before the second monitoring time has elapsed after the output of the AC output power is resumed after the fourth waiting time has elapsed (S30) (YES in S33), the control circuit 35 stops the output of the AC output power (S21) and stops the input of the input power (S22).
  • step S37 the control circuit 35 determines whether the time difference is within a third predetermined time that is longer than the second predetermined time (step S37).
  • the third predetermined time is, for example, about 10,000 times the period corresponding to the reference frequency of the inverter circuit 312, and is about 2 s to 10 s.
  • step S37 if the time difference is not within the third predetermined time (step S37: NO), the process returns to step S10, and the control circuit 35 sets the number of abnormalities to 0 (see FIG. 4). In other words, if a sufficient amount of time has passed since the detection of the abnormality, the possibility of a discharge phenomenon occurring is considered to be low, so the number of abnormalities is reset to 0.
  • step S37 determines whether the number of abnormalities is 2 or less (S38).
  • step S38 if the number of abnormalities is 2 or less (S38: YES), the control circuit 35 sets the first protection device 33 to the OFF state to stop the output of the AC output power (S39).
  • the control circuit 35 outputs a third abnormality notification (S40).
  • the third abnormality notification indicates that an abnormality that may cause a disproportionation reaction has occurred in the refrigeration cycle device 1.
  • the third abnormality notification is output to, for example, the control circuit of the indoor unit 1b and a remote controller.
  • the control circuit 35 determines whether a second standby time has elapsed since the output of the AC output power was stopped (S41).
  • the second standby time is longer than the first standby time.
  • the second standby time is, for example, 10 s.
  • the control circuit 35 sets the first protection device 33 to the ON state to resume the output of the AC output power (S42), thereby resuming the operation of the compressor 4 (S43). Thereafter, the process returns to step S11.
  • the control circuit 35 switches from the first path R1 to the second path R2 using the switching device 36 to reduce the internal pressure of the compressor 4 to below the predetermined pressure. Furthermore, the control circuit 35 stops output of the AC output power. The control circuit 35 resumes output of the AC output power when a second standby time longer than the first standby time has elapsed since the stop of output of the AC output power (S42).
  • step S38 if the number of abnormalities is not 2 or less (S38: NO), that is, if the number of abnormalities is 3 or more, the control circuit 35 sets the first protection device 33 to the off state to stop the output of AC output power (S44).
  • the control circuit 35 changes the switching control of the semiconductor switching element of the drive circuit 31 so that the set value of the amplitude of the AC output power is reduced from E to E/2 (S45).
  • the control circuit 35 outputs a second abnormality notification (S46).
  • the control circuit 35 determines whether the third standby time has elapsed since the output of the AC output power was stopped (S47).
  • the third standby time is longer than the second standby time.
  • the third standby time is, for example, 60 seconds.
  • the control circuit 35 sets the first protection device 33 to the ON state to resume the output of the AC output power (S48), switches the switching device 36 from the second path R2 to the first path R1, and resumes the operation of the compressor 4 (S49). In this case, the set value of the amplitude of the AC output power remains lowered from E to E/2.
  • the control circuit 35 switches from the first path R1 to the second path R2 using the switching device 36 to reduce the internal pressure of the compressor 4 to below the predetermined pressure. Furthermore, the control circuit 35 stops the output of the AC output power (S44) and reduces the set value of the amplitude of the AC output power (S45). When a third standby time longer than the second standby time has elapsed since the output of the AC output power was stopped, the control circuit 35 resumes the output of the AC output power while keeping the set value of the amplitude of the AC output power reduced (S48).
  • control circuit 35 acquires the detection voltage from the state detection circuit 32 (S50). The control circuit 35 determines whether the detection voltage is less than the second voltage (S51).
  • step S51 if the detected voltage is less than the second voltage (S51: YES), the control circuit 35 switches from the first path R1 to the second path R2 by the switching device 36 (S52), and proceeds to step S21 in FIG. 5.
  • step S51 if the detected voltage is not less than the second voltage (S51: NO), the control circuit 35 determines whether the first monitoring time has elapsed since the compressor 4 restarted operating (S53).
  • the first monitoring time may be the same as or different from the second monitoring time in step S35.
  • step S53 if the first monitoring time has elapsed since the compressor 4 restarted operating (S53: YES), the control circuit 35 cancels the reduction in the set value of the amplitude of the AC output power, returns the set value of the amplitude of the AC output power to E (S54), and proceeds to step S11 in FIG. 4.
  • step S53 if the first monitoring time has not elapsed since the compressor 4 restarted operation (S53: NO), the process returns to step S50.
  • steps S50 to S53 if the detected voltage becomes less than the second voltage between the time when the compressor 4 restarts operation and the time when the first monitoring time has elapsed, the process proceeds to step S21 in FIG. 5, and if the detected voltage does not become less than the second voltage between the time when the compressor 4 restarts operation and the time when the first monitoring time has elapsed, the process proceeds to step S54.
  • the control circuit 35 cancels the reduction in the set value of the amplitude of the AC output power (S54). If the detected voltage becomes less than the second voltage before the first monitoring time has elapsed from when the output of the AC output power is resumed after the third waiting time has elapsed (S48) (YES in S51), the control circuit 35 switches from the first path R1 to the second path R2 using the switching device 36, and reduces the internal pressure of the compressor 4 to a predetermined pressure or lower. Furthermore, the control circuit 35 stops the output of the AC output power (S21) and stops the input of the input power (S22).
  • the control device 3 described above includes the compressor 4, the condenser (first heat exchanger 5, second heat exchanger 7), the expansion valve 6, and the evaporator (first heat exchanger 5, second heat exchanger 7), and controls the refrigeration cycle circuit 2 in which the working medium 20 circulates.
  • the control device 3 includes a drive circuit 31 that drives the compressor 4, a state detection circuit 32 that detects the state of at least one of the compressor 4 and the drive circuit 31, a switching device 36 that can switch between a first route R1 that connects a discharge pipe 402 of the compressor 4 to the condenser (first heat exchanger 5, second heat exchanger 7) and a second route R2 that connects the discharge pipe 402 of the compressor 4 to a predetermined space that reduces the internal pressure of the compressor 4 to a predetermined pressure or lower, and a control circuit 35 that controls the drive circuit 31 and the switching device 36.
  • the control circuit 35 switches the first route R1 to the second route R2 by the switching device 36. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the specified space is a space with a pressure of 0.4 MPa or less.
  • the pressure inside the compressor 4 is 2.0 MPa or less. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the specified pressure is 3.0 MPa or less. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the switching device 36 is located between the discharge pipe 402 of the compressor 4 and the condenser.
  • the first route R1 connects the discharge pipe 402 of the compressor 4 to the condenser.
  • the second route R2 connects the discharge pipe 402 of the compressor 4 to a specified space. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the refrigeration cycle circuit 2 includes an accumulator 9 located on the suction pipe 401 side of the compressor 4.
  • the second route R2 connects the discharge pipe 402 of the compressor 4 to the internal space of the accumulator 9. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • switching from the second route R2 to the first route R1 allows the refrigeration cycle circuit 2 to return to normal operation (cooling operation, heating operation).
  • control circuit 35 stops or limits the operation of the drive circuit 31 when the state of at least one of the compressor 4 and the drive circuit 31 indicates an unsteady state (in response to detection of an abnormality in at least one of the compressor 4 and the drive circuit 31). This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the drive circuit 31 includes a converter circuit 311 that outputs DC output power based on the input power from the power source 10 so that the voltage becomes a first voltage, and an inverter circuit 312 that outputs AC output power to the compressor 4 based on the DC output power.
  • the state detection circuit 32 detects the DC output power and outputs a detection voltage indicating the voltage of the DC output power.
  • the non-steady state includes a state in which the detection voltage is less than a second voltage that is equal to or less than the first voltage. This configuration enables early detection of signs of a disproportionation reaction of the working medium 20 and enables improved suppression of the disproportionation reaction of the working medium 20.
  • the second voltage is 0.3 to 0.8 times the first voltage. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the refrigeration cycle device 1 described above includes a control device 3 and a refrigeration cycle circuit 2. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the working medium 20 contains an ethylene-based fluoroolefin. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • 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 enables improved suppression of the disproportionation reaction of the working medium 20.
  • the working medium 20 further contains difluoromethane. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the working medium 20 further contains saturated hydrocarbons. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the working medium 20 contains a haloalkane having one or two carbon atoms as a disproportionation inhibitor that suppresses the disproportionation reaction of ethylene-based fluoroolefins.
  • This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the disproportionation inhibitor can prolong the induction period. Therefore, the possibility that the disproportionation reaction will progress before the control circuit 35 reduces the internal pressure of the compressor 4, and the reduction in the internal pressure of the compressor 4 and the long induction period can more effectively suppress the disproportionation reaction of the working medium 20.
  • the saturated hydrocarbons include n-propane. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the control device 3 described above can be said to execute the following control method.
  • the control method is executed by the control device 3 that controls the refrigeration cycle circuit 2, which includes the compressor 4, the condenser (first heat exchanger 5, second heat exchanger 7), the expansion valve 6, and the evaporator (first heat exchanger 5, second heat exchanger 7) and through which the working medium 20 circulates.
  • the control device 3 includes a drive circuit 31 that drives the compressor 4, and a control circuit 35 that controls the drive circuit 31.
  • the control method connects the discharge pipe 402 of the compressor 4 to a predetermined space and reduces the internal pressure of the compressor 4 to a predetermined pressure or lower. This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the control method executed by the control device 3 can be realized by a computer system executing a program.
  • This program is executed by a computer system equipped with the control device 3, which includes the compressor 4, the condenser (first heat exchanger 5, second heat exchanger 7), the expansion valve 6, and the evaporator (first heat exchanger 5, second heat exchanger 7), and controls the refrigeration cycle circuit 2 through which the working medium 20 circulates.
  • the control device 3 includes a drive circuit 31 that drives the compressor 4, and a control circuit 35 that controls the drive circuit 31.
  • the program instructs the computer system to connect the discharge pipe 402 of the compressor 4 to a predetermined space and reduce the internal pressure of the compressor 4 to a predetermined pressure or lower when the state of at least one of the compressor 4 and the drive circuit 31 indicates an unsteady state of the refrigeration cycle circuit 2 (in response to detection of an abnormality in at least one of the compressor 4 and the drive circuit 31).
  • This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • FIG. 10 is a block diagram of a refrigeration cycle apparatus 1A according to the present embodiment.
  • the refrigeration cycle apparatus 1A includes a refrigeration cycle circuit 2A and a control device 3A.
  • the control device 3A includes a drive circuit 31, a state detection circuit 32, a first protection device 33, a second protection device 34, a control circuit 35, and a switching device 36A.
  • the switching device 36A is a four-way valve that switches the direction in which the working medium 20 circulates through the refrigeration cycle circuit 2A between a first direction A1 corresponding to cooling operation and a second direction A2 corresponding to heating operation.
  • the first route R1 corresponds to the second direction and connects the discharge pipe 402 of the compressor 4 to the second heat exchanger 7.
  • the second route R2 corresponds to the first direction and connects the discharge pipe 402 of the compressor 4 to the first heat exchanger 5.
  • the first heat exchanger 5 functions as a condenser during cooling operation, but functions as an evaporator during heating operation.
  • the internal pressure of the evaporator is lower than the internal pressure of the condenser.
  • the internal space of the first heat exchanger 5, which functions as an evaporator during heating operation, constitutes the specified space. Therefore, the specified space is inside the refrigeration cycle circuit 2A.
  • the four-way valve 8 of the refrigeration cycle device 1 of the first and second embodiments is used as the switching device 36A. Therefore, in the third embodiment, there is no need to add any configuration to the refrigeration cycle circuit 2A, and there is no need to change the existing configuration of the refrigeration cycle circuit 2A itself. This allows for cost reduction.
  • the control circuit 35 switches from the first route R1 to the second route R2 by the switching device 36A, and increases the opening of the expansion valve 6.
  • the discharge pipe 402 of the compressor 4 is connected from the second heat exchanger 7, which functions as a condenser during heating operation, to the first heat exchanger 5, which functions as an evaporator during heating operation. Since the internal pressure of the evaporator is lower than the internal pressure of the condenser, the internal pressure of the compressor 4 is reduced to a predetermined pressure or lower.
  • the refrigeration cycle circuit 2A includes the first heat exchanger 5 and the second heat exchanger 7.
  • the switching device 36A is a four-way valve that switches the direction in which the working medium 20 circulates through the refrigeration cycle circuit 2A between a first direction A1 corresponding to a cooling operation and a second direction A2 corresponding to a heating operation.
  • the first route R1 corresponds to the second direction and connects the discharge pipe 402 of the compressor 4 to the second heat exchanger 7.
  • the second route R2 corresponds to the first direction and connects the discharge pipe 402 of the compressor 4 to the first heat exchanger 5.
  • the control circuit 35 switches the first route R1 to the second route R2 by the switching device 36A and increases the opening degree of the expansion valve 6.
  • This configuration enables improved suppression of the disproportionation reaction of the working medium 20.
  • the refrigeration cycle circuit 2A since there is no need to change the refrigeration cycle circuit 2A itself, it is possible to reduce costs.
  • the refrigeration cycle circuit 2A can be restored to normal operation (cooling operation, heating operation) by switching from the second route R2 to the first route R1.
  • the control device 3B includes a drive circuit 31, a state detection circuit 32, a first protection device 33, a second protection device 34, a control circuit 35B, a switching device 36, and a measurement circuit 37.
  • the measurement circuit 37 is provided to measure the internal state of the refrigeration cycle circuit 2.
  • the internal state of the refrigeration cycle circuit 2 may include at least one of the pressure, temperature, and amount of product in the refrigeration cycle circuit 2. Therefore, the measurement circuit 37 detects at least one of the pressure, temperature, and amount of product in the refrigeration cycle circuit 2.
  • the pressure in the refrigeration cycle circuit 2 may be, for example, the internal pressure of the compressor 4.
  • the internal pressure of the compressor 4 can be obtained, for example, by a pressure sensor disposed in the refrigerant piping near the discharge pipe 402 of the compressor 4 or in the sealed container 40 of the compressor 4.
  • the temperature inside the refrigeration cycle circuit 2 may be, for example, the internal temperature of the compressor 4.
  • the internal temperature of the compressor 4 can be obtained, for example, by a temperature sensor disposed in the refrigerant piping near the discharge pipe 402 of the compressor 4 or in the sealed container 40 of the compressor 4.
  • the amount of the product may be, for example, the amount of the product generated from the working medium 20 by the disproportionation reaction of the working medium 20.
  • a product may include an intermediate product or a final product.
  • the final product refers to a thermodynamically stable chemical species among the chemical species generated in the disproportionation reaction of the working medium 20.
  • thermodynamically stable means that the type and composition of the compound do not change when exposed to a high temperature of 2000 K or more at 1 atmosphere for a predetermined time (for example, about 10 minutes) and then returned to normal temperature and pressure.
  • the intermediate product refers to a thermodynamically unstable chemical species among the chemical species generated in the disproportionation reaction of the working medium 20.
  • Thermodynamically unstable means that at least one of the type or composition of the compound changes when exposed to a high temperature of 2000 K or more at 1 atmosphere.
  • Thermodynamically unstable chemical species also include so-called metastable chemical species.
  • the intermediate product is one of the chemical species generated in the disproportionation reaction of the working medium 20 that can exist with a lifespan of 1 ms or more, but can decompose at high temperatures (e.g., 2000 K or higher) to generate a final product. Naturally, such intermediate products do not include the final product.
  • the lifespan here is the lifespan in a measurement environment equivalent to the inside of the refrigeration cycle circuit 2.
  • the conditions for measuring the lifespan are a maximum temperature of 500 K and a maximum pressure of 6 MPa.
  • the intermediate products include carbenes, carbene inserts (compounds produced by the insertion reaction of carbene), tetrafluoroethylene, perfluoroolefins, and fluorobenzene.
  • the final products include soot, hydrogen fluoride, and tetrafluoromethane.
  • the amount of products can be measured by utilizing the change in the transmittance of the working medium 20. This is particularly effective when the products circulate within the refrigeration cycle circuit 2 together with the working medium 20 as insoluble components. For example, when the working medium contains an ethylene-based fluoroolefin, soot or hydrogen fluoride (HF) is generated as an insoluble component. When the discharge phenomenon is repeated, the amount of insoluble components such as soot increases. Such an increase in insoluble components is one of the factors that causes the transmittance of the working medium 20 to decrease.
  • HF hydrogen fluoride
  • the measurement circuit 37 may include a light detection circuit that uses transmittance.
  • the light detection circuit that uses transmittance includes, for example, a light source device and a light detection device.
  • the light source device emits light inside the refrigeration cycle circuit 2.
  • the light may be directional light (for example, laser light, or parallel light obtained by parallelizing a light emitting diode (LED) using a lens or a double slit).
  • the color of the light is not particularly limited, and may be white or red with a wavelength of 650 nm to 690 nm.
  • the light detection device receives the light and outputs the intensity of the received light.
  • the light detection device can output a light detection signal indicating the intensity of the light to the control circuit 35B.
  • the light source device may radiate light to the working medium 20 in the refrigeration cycle circuit 2, but the light may be radiated to the working medium 20 in the compressor 4 of the refrigeration cycle circuit 2. Since the discharge phenomenon may occur in the motor 42 of the compressor 4, it is considered that the decrease in transmittance due to insoluble components such as soot in the working medium 20 in the compressor 4 is easily detected.
  • the light detection circuit may be located in the sealed container 40 of the compressor 4.
  • the light source device may radiate light to the working medium 20 in the region between the motor 42 and the suction pipe 401.
  • the working medium 20 may contain bubbles.
  • the bubbles in the working medium 20 scatter light, which may cause a decrease in the transmittance of the working medium 20, and may adversely affect the evaluation using the transmittance.
  • the amount of bubbles is small in the region between the motor 42 and the suction pipe 401. Therefore, it is possible to suppress the decrease in accuracy due to bubbles.
  • the amount of the product can be measured using a fluorescent dye.
  • the product generated by the chemical reaction of the working medium 20 may circulate in the refrigeration cycle circuit 2 together with the working medium 20.
  • the working medium contains an ethylene-based fluoroolefin
  • an example of the product generated by the chemical reaction of the working medium 20 (hereinafter also referred to as product (A)) is hydrogen fluoride (HF).
  • product (A) is an example of a product generated from the working medium 20 by a disproportionation reaction.
  • the discharge phenomenon is repeated, the amount of product (A) increases. The increase in product (A) may also cause an abnormality in the refrigeration cycle circuit 2.
  • a fluorescent dye can be used to quantitatively evaluate product (A).
  • the fluorescent dye has the property of changing at least one of the fluorescence wavelength or quantum yield by reacting with product (A)
  • the increase in product (A) can be observed as a change in the intensity of light at a wavelength corresponding to the fluorescence wavelength of the fluorescent dye.
  • the product (A) can be quantitatively evaluated.
  • the measurement circuit 37 may include a light detection circuit that uses a phosphor.
  • the phosphor contains a fluorescent dye and is arranged in the refrigeration cycle circuit 2 so as to be able to come into contact with the working medium 20.
  • the phosphor is refrigeration oil in which the fluorescent dye has been dissolved.
  • the phosphor may be formed by dissolving the fluorescent dye in the refrigeration oil of the compressor 4.
  • the phosphor circulates through the refrigeration cycle circuit 2 together with the working medium 20. This increases the possibility that the fluorescent dye of the phosphor will come into contact with and react with the product (A).
  • the fluorescent dye has the property of reacting with product (A) produced by the chemical reaction of the working medium 20, causing a change in at least one of the fluorescence wavelength or quantum yield. Therefore, depending on the type of fluorescent dye, the reaction between the fluorescent dye and product (A) can cause an increase or decrease in the amount of light of the fluorescent wavelength.
  • fluorescent dyes are particularly preferred when the product (A) is a substance that generates fluoride ions (e.g., hydrogen fluoride).
  • the fluorescent dye may be a triarylfluorosilane compound.
  • the triarylfluorosilane compound is represented, for example, by SiFR1R2R3 (see formula ( 1 )).
  • R1 , R2 and R3 are all anthracene or a derivative thereof, or R1 and R2 are anthracene or a derivative thereof and R3 is benzene or a derivative thereof.
  • the fluorescent dye may be a compound having a structure in which a donor group and an acceptor group are bonded.
  • the donor group has donor properties in an excited state.
  • the donor group is a chromophore.
  • the acceptor group has high acceptor properties in a free state and has low acceptor properties when bonded to the product (A) or an ion derived from the product (A).
  • the acceptor group is a receptor.
  • the acceptor group may be selected from the group consisting of a compound having a structure in which two or more amino groups are bonded via one or two methylene groups (hereinafter also referred to as compound (B)), a compound having a structure in which two or more pyrrole groups or indole groups are bonded via two methylene groups (hereinafter also referred to as compound (C)), benzamide, bis(methylidene)hydrazine, and calixarene.
  • compound (B) a compound having a structure in which two or more amino groups are bonded via one or two methylene groups
  • compound (C) a compound having a structure in which two or more pyrrole groups or indole groups are bonded via two methylene groups
  • benzamide bis(methylidene)hydrazine
  • calixarene arene
  • Examples of compound (B) include urea and its derivatives, thiourea and its derivatives, and polyamine macrocycles.
  • compound (C) examples include 1,2-ethanediyl-bis(pyrrole) and 1,2-ethanediyl-bis(indol).
  • the donor group may be selected from the group consisting of anthracene, naphthalimide, pyrene, bodipy, fluorescein, rhodamine, resorufin, coumarin, and cyanine.
  • some of the fluorescent dyes mentioned above change their fluorescent wavelengths upon reaction with product (A).
  • the fluorescent wavelength for an excitation wavelength of 366 nm changes from 416 nm to 396 nm. Therefore, the presence of product (A) can be detected by a decrease in the intensity of light with a fluorescent wavelength of 416 nm or an increase in the intensity of light with a fluorescent wavelength of 396 nm.
  • the photodetection circuit using a phosphor may include a light source device and a photodetection device.
  • the light source device emits excitation light having a wavelength corresponding to the excitation wavelength of the fluorescent dye into the refrigeration cycle circuit 2.
  • the excitation light may be directional light (e.g., laser light).
  • the wavelength range of the excitation light may include the excitation wavelength of the fluorescent dye. However, it is preferable that the wavelength range of the excitation light does not include the fluorescent wavelength of the fluorescent dye.
  • the light source device may be, for example, a laser diode.
  • the photodetection device receives light having a wavelength corresponding to the fluorescent wavelength of the fluorescent dye and outputs the intensity of the received light.
  • the photodetection device may output a photodetection signal indicating the intensity of the light to the control circuit 35B.
  • the wavelength range to which the photodetection device is sensitive may include the fluorescent wavelength of the fluorescent dye. However, when the fluorescent wavelength of the fluorescent dye changes, it is preferable that the wavelength range to which the photodetection device is sensitive includes only one of the fluorescent wavelength before the change and the fluorescent wavelength after the change. It is also preferable that the wavelength range to which the photodetection device is sensitive does not include the excitation wavelength of the fluorescent dye.
  • the photodetection device includes, for example, a photodiode and an optical system (e.g., a lens, etc.).
  • the light source device preferably radiates excitation light to the portion between the discharge pipe 402 of the compressor 4 in the refrigeration cycle circuit 2 and the condenser (the first heat exchanger 5 during cooling operation, and the second heat exchanger 7 during heating operation).
  • the light source device preferably radiates excitation light to the portion between the discharge pipe 402 of the compressor 4 and the four-way valve 8. Since the light source device radiates excitation light to a portion closer to the discharge pipe 402 of the compressor 4 than the four-way valve 8, the possibility of the excitation light hitting the fluorescent element can be increased.
  • the optical detection device preferably receives light from a portion between the discharge pipe 402 of the compressor 4 in the refrigeration cycle circuit 2 and the condenser (the first heat exchanger 5 during cooling operation, and the second heat exchanger 7 during heating operation).
  • the optical detection device preferably receives light from a portion between the discharge pipe 402 of the compressor 4 and the four-way valve 8. Since the optical detection device receives light from a portion closer to the discharge pipe 402 of the compressor 4 than the four-way valve 8, the intensity of the light received by the optical detection device can be improved.
  • the fluorescent material is not limited to refrigeration oil in which the fluorescent dye is dissolved.
  • the fluorescent material may be a support carrying the fluorescent dye.
  • the support is, for example, a porous body.
  • the porous body may be an inorganic or organic porous body.
  • An example of an inorganic porous body is mesoporous silica.
  • An example of an organic porous body is a synthetic resin membrane or paper. Since a porous body can secure a larger surface area, it is possible to increase the possibility that the fluorescent dye will come into contact with the working medium 20.
  • Such a fluorescent material may be fixed at a predetermined location in the refrigeration cycle circuit 2.
  • the fluorescent material may be disposed in the sealed container 40 of the compressor 4, and may be located in the area between the electric motor 42 and the discharge pipe 402.
  • the fluorescent dye is not dispersed throughout the refrigeration cycle circuit 2 but is located at a predetermined location, so the possibility of contact with the working medium 20 is reduced, but the excitation light can be reliably applied.
  • the amount of the product can be measured using a dye.
  • a product generated by a chemical reaction of the working medium 20 may circulate in the refrigeration cycle circuit 2 together with the working medium 20.
  • the product generated by the chemical reaction of the working medium 20 (hereinafter also referred to as product (D)) may be tetrafluoroethylene (C 2 F 4 ) or hydrogen fluoride (HF).
  • product (D) is an example of a product generated from the working medium 20 by a disproportionation reaction.
  • the discharge phenomenon is repeated, the amount of product (D) increases. The increase in product (D) may also cause an abnormality in the refrigeration cycle circuit 2.
  • a dye can be used to quantitatively evaluate the product (D).
  • the increase in product (D) can be observed as a change in the intensity of light in a wavelength band including the absorption wavelength of the dye. It is desirable that the difference between the maximum absorption wavelength of the dye and the maximum absorption wavelength of the dye after reaction with product (D) be large enough to enable a sufficient distinction between the waveform of the wavelength change of absorbance of the dye and the waveform of the wavelength change of absorbance of the dye after reaction with product (D).
  • the product (D) can be quantitatively evaluated.
  • the measurement circuit 37 may include a light detection circuit that uses a light absorber.
  • the light absorber contains a dye and is arranged in the refrigeration cycle circuit 2 so that it can come into contact with the working medium 20.
  • the light absorber is refrigeration oil in which a dye has been dissolved.
  • the light absorber is formed by dissolving a dye in the refrigeration oil of the compressor 4.
  • the light absorber circulates through the refrigeration cycle circuit 2 together with the working medium 20. This increases the possibility that the dye in the light absorber will come into contact with and react with the product (D).
  • the dye has the property of reacting with product (D) produced by the chemical reaction of the working medium 20, thereby changing the maximum absorption wavelength. Therefore, depending on the type of dye, the reaction between the dye and product (D) can cause an increase or decrease in the amount of light at the absorption wavelength.
  • the first example of the dye is preferred when the product (D) is tetrafluoroethylene.
  • the first example of the dye may include a nickel complex.
  • the nickel complex may react with tetrafluoroethylene and change its absorbance. Therefore, the presence of tetrafluoroethylene as the product (D) can be detected by a change in the intensity of light at a wavelength at which the absorbance changes.
  • nickel complexes examples include bistriphenylphosphine nickel (0) (see formula (2)), bis(orthodiphenylphosphanylphenyl) ether nickel (0) (see formula (3)), 2,2'-bis(orthodiphenylphosphino)trans-stilbene nickel (0) (see formula (4)), 2,2'-bis(diphenylphosphino)biphenyl nickel (0) (see formula (5)), 2,2'-bis(diphenylphosphino)diphenylmethane nickel (0) (see formula (6)), and 2,2'-bis(diphenylphosphino)diphenylpropane nickel (see formula (7)).
  • the second example of the dye is shown below.
  • the second example of the dye is preferred when the product (D) is hydrogen fluoride.
  • the second example of the dye may include a boron compound having an aromatic substituent.
  • the boron compound having an aromatic substituent may react with hydrogen fluoride and change its absorbance. Therefore, the presence of hydrogen fluoride as the product (D) can be detected by the change in the intensity of light at the wavelength at which the absorbance changes.
  • An example of a boron compound having an aromatic substituent is diarylnaphthylborane represented by formula (8).
  • R 1 and R 2 are each selected from the group consisting of a naphthyl group represented by formula (9) or a mesityl group represented by formula (10).
  • the light detection circuit using the light absorber includes a light source device and a light detection device.
  • the light source device emits light in a wavelength band including the absorption wavelength of the dye inside the refrigeration cycle circuit 2.
  • the light source device may include a first light source and a second light source.
  • the first light source and the second light source can emit first light and second light having different wavelength bands inside the refrigeration cycle circuit 2. This means that the first light and the second light correspond to different absorption wavelengths of the dye.
  • the light source device may emit multiple lights with different wavelength bands.
  • the first light and the second light are directional lights (e.g., laser lights).
  • the first light source and the second light source are, for example, laser diodes.
  • the light detection device receives the first light and the second light from the light source device and outputs the intensities of the received first light and second light.
  • the light detection device may output a light detection signal indicating the intensities of the received first light and second light to the control circuit 35B.
  • the light detection device may include, for example, a first light detector and a second light detector.
  • the first light detector may be arranged to receive a first light emitted from a first light source
  • the second light detector may be arranged to receive a second light emitted from a second light source.
  • Each of the first light detector and the second light detector may include a light detection element and an optical system.
  • the light detection element may include, for example, a photodiode.
  • the optical system may include, for example, a lens (a focusing lens).
  • the light source device may radiate the first light and the second light to a portion between the discharge pipe 402 of the compressor 4 of the refrigeration cycle circuit 2 and the condenser (the first heat exchanger 5 during cooling operation, and the second heat exchanger 7 during heating operation).
  • the light source device may radiate the first light and the second light to a portion between the discharge pipe 402 of the compressor 4 and the four-way valve 8.
  • the optical detection device receives the first light and the second light from a portion between the discharge pipe 402 of the compressor 4 of the refrigeration cycle circuit 2 and the condenser (the first heat exchanger 5 during cooling operation, and the second heat exchanger 7 during heating operation).
  • the optical detection device may receive the first light and the second light from a portion between the discharge pipe 402 of the compressor 4 and the four-way valve 8.
  • the optical detection device can improve the intensity of the first light and the second light received by the optical detection device.
  • the light absorber is not limited to refrigeration oil in which the dye is dissolved.
  • the light absorber may be a support carrying the dye.
  • the support is, for example, a porous body.
  • the porous body may be an inorganic or organic porous body.
  • An example of an inorganic porous body is mesoporous silica.
  • An example of an organic porous body is a synthetic resin membrane or paper.
  • the porous body can secure a larger surface area, so that the possibility of the dye coming into contact with the working medium 20 can be increased. It is preferable that the porous body has a property of transmitting light without blocking it.
  • the light absorber is fixed at a predetermined location in the refrigeration cycle circuit 2.
  • the light absorber may be disposed in the sealed container 40 of the compressor 4.
  • the light absorber may be located in the area between the electric motor 42 and the discharge pipe 402.
  • the dye is not dispersed throughout the refrigeration cycle circuit 2 but is located at a predetermined location, so that the possibility of contact with the working medium 20 is reduced, but light can be reliably applied.
  • the control circuit 35B stops the operation of the drive circuit 31 after switching the first route R1 to the second route R2 by the switching device 36.
  • the control circuit 35B determines that the unsteady state is not continuing based on time-dependent changes in at least one of the pressure, temperature, and amount of product in the refrigeration cycle circuit 2, it resumes the operation of the drive circuit 31.
  • FIG. 12 is a flowchart of the first example of the operation of the control circuit 35B of the control device 3B.
  • the control circuit 35B acquires the detection voltage from the state detection circuit 32 (S60). The control circuit 35B determines whether the detection voltage is less than the second voltage (S61).
  • Step S60 and S61 cause the control circuit 35B to determine whether the detected voltage is less than the second voltage at a predetermined period.
  • the predetermined period here is preferably shorter than the period corresponding to the reference frequency of the inverter circuit 312 (e.g., 1000 to 5000 Hz).
  • step S61 if the detected voltage is less than the second voltage (S61: YES), the control circuit 35B switches from the first route R1 to the second route R2 by the switching device 36 (S62). As a result, the control circuit 35B reduces the internal pressure of the compressor 4 to a predetermined pressure or lower. The reduction in the internal pressure of the compressor 4 increases the discharge energy required for the disproportionation reaction to proceed, thereby suppressing the disproportionation reaction.
  • control circuit 35B stops the operation of the compressor 4 (S63).
  • control circuit 35B sets the first protection device 33 to the OFF state to stop the output of AC output power.
  • control circuit 35B acquires the internal state from the measurement circuit 37 (S64).
  • the control circuit 35B determines whether the unsteady state of the refrigeration cycle circuit 2 continues based on the internal state (S65).
  • the internal state may include at least one of the pressure, temperature, and amount of product in the refrigeration cycle circuit 2.
  • the control circuit 35B determines whether the unsteady state continues based on a change over time in at least one of the pressure, temperature, and amount of product in the refrigeration cycle circuit 2.
  • the control circuit 35B may determine that the unsteady state continues if the amount or rate of increase in pressure in the refrigeration cycle circuit 2 during a specified time is equal to or greater than a threshold value.
  • a threshold value For example, with respect to pressure, the specified time may be 10 seconds, and the threshold value may be a 10% increase amount.
  • the control circuit 35B may determine that the unsteady state continues if the increase in temperature in the refrigeration cycle circuit 2 during a specified time is equal to or greater than a threshold value.
  • a threshold value For example, with respect to temperature, the specified time may be 10 s and the threshold value may be 50 K.
  • the control circuit 35B may determine that the unsteady state continues when the increase or volume fraction of the product in the refrigeration cycle circuit 2 during a predetermined time is equal to or greater than a threshold value.
  • the predetermined time and the threshold value depend on the type of product. As an example, when the product is hydrogen fluoride, the predetermined time may be 30 s, and the threshold value may be 0.1% in terms of volume fraction.
  • the amount of light emitted, transmittance, or absorbance may be used to indicate the amount of the product.
  • step S65 If it is determined in step S65 that the unsteady state of the refrigeration cycle circuit 2 is not continuing (S65: NO), the control circuit 35B sets the first protection device 33 to the ON state to resume the output of AC output power, thereby resuming the operation of the compressor 4 (S66). Then, the process returns to step S60.
  • step S65 If it is determined in step S65 that the unsteady state of the refrigeration cycle circuit 2 continues (S65: YES), the control circuit 35B determines whether the pause time has elapsed since it determined that the unsteady state of the refrigeration cycle circuit 2 continues (S67).
  • the pause time is, for example, 60 seconds.
  • the control circuit 35B increments the pause count by 1 and determines whether the pause count has exceeded a predetermined number (S68).
  • the predetermined number is, for example, 5.
  • step S68 If it is determined in step S68 that the number of pauses has exceeded the predetermined number (S68: YES), the control circuit 35B outputs an abnormality notification (S69).
  • the abnormality notification indicates that an abnormality has occurred in the refrigeration cycle device 1 that is highly likely to cause a disproportionation reaction.
  • step S68 If it is determined in step S68 that the number of pauses has not exceeded the predetermined number (S68: NO), the process returns to step S64.
  • the control circuit 35B confirms that the non-steady state of the refrigeration cycle circuit 2 is not continuing when restarting the operation of the compressor 4. Therefore, the operation of the drive circuit 31 can be restarted in a state where the possibility of the disproportionation reaction of the working medium 20 occurring is reduced. This makes it possible to improve the suppression of the disproportionation reaction of the working medium 20 while improving the continuity of the operation of the refrigeration cycle circuit 2.
  • Steps S70 to S75 in FIG. 13 are the same as steps S60 to S65 in FIG. 12, so their explanation is omitted.
  • step S75 If it is determined in step S75 that the unsteady state of the refrigeration cycle circuit 2 is not continuing (S75: NO), the control circuit 35B performs idling operation (S76).
  • the idling operation is performed to stabilize the state of the working medium 20.
  • the idling operation circulates the working medium 20 to suppress the refrigerant components of the working medium 20 from stagnation. Since such idling operation is well known, a detailed description is omitted.
  • the control circuit 35B resumes the operation of the compressor 4 with its functions restricted (S77).
  • control circuit 35B changes the switching control of the semiconductor switching element of the drive circuit 31 so that the set value of the amplitude of the AC output power is reduced from E to E/2, and sets the first protection device 33 to the ON state to resume the output of the AC output power.
  • control circuit 35B acquires the detection voltage from the state detection circuit 32 (S78). The control circuit 35B determines whether the detection voltage is less than the second voltage (S79).
  • the control circuit 35 releases the restriction on the function of the compressor 4 and operates the compressor 4 normally (S80). For example, the control circuit 35B releases the reduction in the set value of the amplitude of the AC output power and returns the set value of the amplitude of the AC output power to E. After step S80, the process returns to step S70.
  • step S79 If the detected voltage is less than the second voltage in step S79 (S79: YES), proceed to step S72.
  • step S75 If it is determined in step S75 that the unsteady state of the refrigeration cycle circuit 2 continues (S75: YES), the process proceeds to step S81.
  • Steps S81, S82, and S83 are the same as steps S67, S68, and S69 in FIG. 12, and therefore will not be described here.
  • control circuit 35B confirms that the unsteady state of the refrigeration cycle circuit 2 is not continuing when restarting the operation of the compressor 4. Therefore, the operation of the drive circuit 31 can be restarted in a state where the possibility of the disproportionation reaction of the working medium 20 occurring is reduced. This makes it possible to improve the suppression of the disproportionation reaction of the working medium 20 while improving the continuity of the operation of the refrigeration cycle circuit 2.
  • the operation of the compressor 4 can be gradually restarted, which allows for further improvement in the suppression of the disproportionation reaction of the working medium 20.
  • the control circuit 35B stops the operation of the drive circuit 31 after switching the first route R1 to the second route R2 by the switching device 36, and when it is determined that the unsteady state does not continue based on a time-dependent change in at least one of the pressure, temperature, and amount of the product in the refrigeration cycle circuit 2, it resumes the operation of the drive circuit 31.
  • This configuration can resume the operation of the drive circuit 31 in a state where the possibility of the disproportionation reaction of the working medium 20 occurring is reduced. Therefore, it is possible to improve the suppression of the disproportionation reaction of the working medium 20 while improving the continuity of the operation of the refrigeration cycle circuit 2.
  • the configuration of the switching device 36 is not limited to the above embodiment.
  • the second path R2 may connect the discharge pipe 402 of the compressor 4 to a container that can store the working medium 20, rather than the discharge port 11. In this way, the working medium 20 is not discharged outside the refrigeration cycle circuit 2, making it possible to return to normal operation (cooling operation, heating operation) of the refrigeration cycle circuit 2.
  • stopping the operation of the drive circuit 31 may include one or more of stopping the output of AC output power, stopping the output of DC output power, or stopping the input of input power.
  • Restricting the operation of the drive circuit 31 may include one or more of reducing the set value of the amplitude of the AC output power, or reducing the set value of the frequency of the AC output power.
  • control circuit 35 may gradually stop and decelerate the electric motor 42. As one example, the control circuit 35 may gradually reduce the effective value of the AC output power supplied to the electric motor 42 by gradually reducing at least one of the amplitude and frequency of the AC output power.
  • control circuit 35 is not necessarily limited to the operations shown in the flowcharts shown in Figures 4 to 9.
  • the flowcharts shown in Figures 4 to 9 are merely examples.
  • the processes of steps S20 to S24 i.e., the processes of stopping the output of AC output power and stopping the input of input power
  • the processes of steps S25 to S29 i.e., the processes of stopping the output of AC output power and lowering the set value of the amplitude of the AC output power after the standby time has elapsed
  • the processes of steps S30 to S36, steps S37 to S43, or steps S42 to S51 are not essential.
  • steps S19, S31, S43, and S49 when restarting the operation of the compressor 4, it is preferable to confirm that the internal pressure of the compressor 4 is equal to or lower than the threshold value before switching from the second route R2 to the first route R1 by the switching device 36. In other words, it is preferable to restart the operation of the compressor 4 when the internal pressure of the compressor 4 has decreased and the possibility of the occurrence of a disproportionation reaction is low.
  • the internal pressure of the compressor 4 can be obtained, for example, by a pressure sensor disposed in the refrigerant piping near the discharge pipe 402 of the compressor 4 or in the sealed container 40 of the compressor 4.
  • the threshold value can be set based on the internal pressure of the compressor 4 during normal operation of the refrigeration cycle device 1.
  • the control circuit 35 does not necessarily have to stop or limit the operation of the drive circuit 31 in a different manner depending on the time difference between the first time when the detected voltage first becomes less than the second voltage and the second time when the detected voltage next becomes less than the second voltage, or the number of times the detected voltage becomes less than the second voltage.
  • the first protection device 33 is not limited to a circuit configuration including switches Su, Sv, and Sw, and may include a circuit configuration that adjusts the magnitude of the AC output power output from the drive circuit 31 to the electric motor 42, for example, the magnitude of the voltage.
  • the first protection device 33 may be disposed within the drive circuit 31.
  • the second protection device 34 is not limited to a circuit configuration including switches S1 and S2, and may include a circuit configuration that adjusts the magnitude of the input power input from the power source 10 to the drive circuit 31, for example, the magnitude of the voltage.
  • the second protection device 34 may be disposed within the drive circuit 31.
  • the control device 3 does not necessarily have to include both the first protection device 33 and the second protection device 34, and may include either the first protection device 33 or the second protection device 34, and if the drive circuit 31 has a function of adjusting the AC output power, the first and second protection devices 33, 34 can be omitted.
  • the control circuit 35 may stop the output of AC output power to the motor 42 by turning on the semiconductor switching elements V1 to V4 of the inverter circuit 312 and turning off the remaining semiconductor switching elements U1 to U4, W1 to W4.
  • the first protection device 33 may be omitted.
  • FIG. 15 shows a modified control device 3C.
  • the control device 3C includes a third protection device 38.
  • the third protection device 38 is provided to stop the output of DC output power.
  • the third protection device 38 includes switches S3, S4, and S5 interposed between the converter circuit 311 and the inverter circuit 312 of the drive circuit 31.
  • the switch S3 is commonly connected between the first output point P1 and the semiconductor switching elements U1, V1, and W1.
  • the switch S4 is commonly connected between the second output point P2 and the semiconductor switching elements U4, V4, and W4.
  • the switch S5 is commonly connected between the third output point P3 and the connection point between the diodes D5 and D6, the connection point between the diodes D7 and D8, and the connection point between the diodes D9 and D10.
  • the switches S3, S4, and S5 may be controllable switches such as semiconductor switches and electromagnetic relays.
  • the third protection device 38 allows the output of DC output power from the converter circuit 311 to the inverter circuit 312 when the switches S3, S4, and S5 are closed in the on state, and stops the output of DC output power from the converter circuit 311 to the inverter circuit 312 when the switches S3, S4, and S5 are open in the off state.
  • the safety level increases in the order of stopping the input of input power, stopping the output of DC output power, and stopping the output of AC output power. Therefore, after the operation of the first protection device 33, the third protection device 38 may be operated before the operation of the second protection device 34. Note that if the third protection device 38 is present, the second protection device 34 may be omitted.
  • the third protection device 38 is not limited to a circuit configuration including switches S3, S4, and S5, but may include a circuit configuration that adjusts the magnitude of the DC output power output from the converter circuit 311 to the inverter circuit 312, for example, the magnitude of the voltage.
  • the state detection circuit 32 is not limited to a configuration that detects the voltage value of the DC output power of the converter circuit 311.
  • the state detection circuit 32 may be configured to detect the state of at least one of the compressor 4 and the drive circuit 31.
  • the state of the drive circuit 31 may be the current value of the current flowing through the connection lines corresponding to the three phases of the AC output power output from the inverter circuit 312 to the compressor 4.
  • the state detection circuit 32 may detect the AC output power.
  • the abnormality of the drive circuit 31 may include an abnormality related to a leakage current detected between the connection lines corresponding to the three phases of the AC output power. Since the method of detecting an abnormality related to a leakage current is conventionally well known, a detailed description will be omitted.
  • the state of the drive circuit 31 may be the current value of the current flowing through the drive circuit 31.
  • the current value of the current flowing through the drive circuit 31 may include at least one of the current values of the output AC current of the U-phase, V-phase, and W-phase legs of the drive circuit 31.
  • the abnormality of the drive circuit 31 is a current abnormality.
  • the control circuit 35 may detect a current abnormality in response to the current value of the current flowing through the drive circuit 31 detected by the state detection circuit 32 exceeding a predetermined current value.
  • the current value of the current flowing through the drive circuit 31 may include the current value of the direct current flowing between the converter circuit 311 and the inverter circuit 312 of the drive circuit 31. In this case, the control circuit 35 may determine that a current abnormality has occurred in the drive circuit 31 if the current value of the direct current flowing between the converter circuit 311 and the inverter circuit 312 of the drive circuit 31 exceeds a predetermined current value.
  • the state of the compressor 4 may include at least one of the phase current of the compressor 4 and the rotation speed of the motor 42 of the compressor 4.
  • the current value of the phase current of the compressor 4 may include the current values of the U-phase, V-phase, and W-phase currents.
  • the abnormality of the compressor 4 may include an abnormality related to a layer short of the compressor 4.
  • An abnormality related to a layer short of the compressor 4 may include the layer short of the compressor 4 itself, an abnormality that may cause a layer short of the compressor 4, and an abnormality that may be caused by a layer short of the compressor 4.
  • Specific examples of abnormalities related to a layer short of the compressor 4 include a layer short of the compressor 4, a leakage current of the compressor 4, and an open-phase operation of the compressor 4.
  • the control circuit 35 may determine whether an abnormality of the compressor 4 has occurred based on the state of the compressor 4 detected by the state detection circuit 32. For example, if an imbalance in the phase currents of the compressor 4 occurs, the control circuit 35 may determine that an abnormality related to a layer short in the compressor 4 has occurred. Also, if a deviation in the rotation speed of the electric motor 42 of the compressor 4 occurs, there is a possibility that an abnormality related to a layer short in the compressor 4 has occurred.
  • the power source 10 may be any of a variety of AC power sources, particularly a commercial power source.
  • the voltage and frequency of the commercial power source vary depending on the country, the drive circuit 31 may be configured to be capable of driving the electric motor 42 using any of a variety of commercial power sources.
  • the drive circuit 31 can be configured to supply AC output power corresponding to the type of the electric motor 42, etc.
  • the AC output power is not limited to three-phase AC power, and can be single-phase AC power.
  • the converter circuit 311 may have a plurality of third output points.
  • the plurality of third output points may output different voltages.
  • the inverter circuit 312 may have a plurality of third semiconductor switching element groups respectively connected between the plurality of third output points and the motor 42. If the total number of the first output point P1, the second output point P2, and the plurality of third output points P3 is n, the drive circuit 31 can provide a voltage of (2 ⁇ n-1) levels. By increasing n, the voltage waveform applied to the motor 42 by the drive circuit 31 can be made closer to a sine wave.
  • the circuit configuration of the inverter circuit 312 is not limited to the circuit configuration in FIG. 2.
  • the circuit configuration of the inverter circuit 312 in FIG. 2 is a so-called NPC (Neutral-Point-Clamped) type, but may be an A-NPC (Advanced-NPC) type.
  • the inverter circuit 312 only needs to have a plurality of semiconductor switching element groups that are respectively connected between a plurality of output points having different voltages and the electric motor.
  • the plurality of semiconductor switching elements that make up the plurality of semiconductor switching element groups may include semiconductor switching elements that are included in common in two or more semiconductor switching element groups.
  • the inverter circuit 312 does not necessarily need to be a multilevel inverter.
  • the refrigeration cycle device 1 is not limited to an air conditioner (so-called room air conditioner (RAC)) configured with one indoor unit connected to one outdoor unit.
  • the refrigeration cycle device 1 may be an air conditioner (so-called package air conditioner (PAC), building multi air conditioner (VRF)) configured with multiple indoor units connected to one or multiple outdoor units.
  • the refrigeration cycle device 1 is not limited to an air conditioner, and may be a refrigeration or cooling device such as a refrigerator or freezer.
  • a control device for controlling a refrigeration cycle circuit in which a working medium circulates including a compressor, a condenser, an expansion valve, and an evaporator
  • the control device includes: A drive circuit for driving the compressor; a state detection circuit for detecting a state of at least one of the compressor and the drive circuit; a switching device capable of switching between a first path connecting a discharge pipe of the compressor to the condenser and a second path connecting the discharge pipe of the compressor to a predetermined space that reduces an internal pressure of the compressor to a predetermined pressure or lower; a control circuit for controlling the drive circuit and the switching device; Equipped with the control circuit switches the first path to the second path by the switching device when a state of at least one of the compressor and the drive circuit detected by the state detection circuit indicates an unsteady state of the refrigeration cycle circuit. Control device.
  • the predetermined space is a space having a pressure of 0.4 MPa or less.
  • the predetermined pressure is 3.0 MPa or less.
  • the switching device is located between a discharge pipe of the compressor and the condenser, the first passage connects a discharge pipe of the compressor to the condenser; The second path connects a discharge pipe of the compressor to the predetermined space.
  • the control device according to any one of aspects 1 to 3.
  • the refrigeration cycle circuit includes an accumulator located on a suction pipe side of the compressor, The second passage connects a discharge pipe of the compressor to an internal space of the accumulator.
  • the refrigeration cycle circuit includes a first heat exchanger and a second heat exchanger
  • the switching device is a four-way valve that switches a direction in which the working medium circulates through the refrigeration cycle between a first direction corresponding to a cooling operation and a second direction corresponding to a heating operation
  • the first path corresponds to the second direction and connects a discharge pipe of the compressor to the second heat exchanger
  • the second path corresponds to the first direction and connects a discharge pipe of the compressor to the first heat exchanger
  • the control circuit switches the first path to the second path using the switching device, and increases an opening degree of the expansion valve.
  • the control device according to any one of aspects 1 to 3.
  • control circuit stops or limits the operation of the drive circuit when the state of at least one of the compressor and the drive circuit detected by the state detection circuit indicates the unsteady state.
  • the control device according to any one of aspects 1 to 6.
  • the drive circuit includes an inverter circuit that outputs AC output power to the compressor, Including, The state detection circuit detects the AC output power, the unsteady state includes an abnormality associated with a leakage current detected between connection lines corresponding to three phases of the AC output power, The control device of aspect 7.
  • the drive circuit includes: a converter circuit that outputs DC output power based on input power from a power source so that the voltage becomes a first voltage; an inverter circuit that outputs AC output power to the compressor based on the DC output power; Including, the state detection circuit detects the DC output power and outputs a detection voltage indicative of a voltage of the DC output power; the non-steady state includes a state in which the detection voltage is less than a second voltage that is equal to or less than the first voltage;
  • the second voltage is 0.3 to 0.8 times the first voltage.
  • the control circuit includes: Stopping the operation of the drive circuit after switching the first path to the second path by the switching device; when it is determined that the unsteady state does not continue based on a time-dependent change in at least one of a pressure, a temperature, and an amount of a product in the refrigeration cycle circuit, the operation of the drive circuit is resumed;
  • the control device according to any one of aspects 1 to 10.
  • a control device according to any one of aspects 1 to 11; The refrigeration cycle circuit; Equipped with Refrigeration cycle equipment.
  • the working medium comprises an ethylene-based fluoroolefin;
  • the refrigeration cycle apparatus of aspect 12 comprises an ethylene-based fluoroolefin;
  • 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 apparatus of aspect 13 is 1,1,2-trifluoroethylene, trans-1,2-difluoroethylene, cis-1,2-difluoroethylene, 1,1-difluoroethylene, tetrafluoroethylene, or monofluoroethylene;
  • the working medium further comprises difluoromethane.
  • the working medium further comprises a saturated hydrocarbon.
  • the working fluid contains a haloalkane having 1 or 2 carbon atoms as a disproportionation inhibitor for suppressing the disproportionation reaction of the ethylenic fluoroolefin.
  • the refrigeration cycle apparatus of aspect 13 contains a haloalkane having 1 or 2 carbon atoms as a disproportionation inhibitor for suppressing the disproportionation reaction of the ethylenic fluoroolefin.
  • the saturated hydrocarbons include n-propane.
  • a control method executed by a control device that controls a refrigeration cycle circuit including a compressor, a condenser, an expansion valve, and an evaporator, and in which a working medium circulates comprising: The control device includes: A drive circuit for driving the compressor; A control circuit for controlling the drive circuit; Equipped with The control method includes connecting a discharge pipe of the compressor to a predetermined space and reducing an internal pressure of the compressor to a predetermined pressure or lower when a state of at least one of the compressor and the drive circuit indicates an unsteady state of the refrigeration cycle circuit. Control methods.
  • a program executed in a computer system of a control device that controls a refrigeration cycle circuit including a compressor, a condenser, an expansion valve, and an evaporator, in which a working medium circulates The control device includes: A drive circuit for driving the compressor; A control circuit for controlling the drive circuit; Equipped with The program causes the computer system to, when a state of at least one of the compressor and the drive circuit indicates an unsteady state of the refrigeration cycle circuit, connect a discharge pipe of the compressor to a predetermined space to reduce an internal pressure of the compressor to a predetermined pressure or lower. program.
  • Aspects 2 to 11 and 13 to 18 are optional elements and are not required. Aspects 2 to 11 and 13 to 18 can be appropriately combined with aspect 19 or 20.
  • This disclosure is applicable to a control device, a refrigeration cycle device, a control method, and a program. Specifically, this disclosure is applicable to a control device for a refrigeration cycle circuit in which the working medium contains an ethylene-based fluoroolefin as a refrigerant component, a refrigeration cycle device including the refrigeration cycle circuit and the control device, a control method executed by the control device, and a program (computer program) used in the control device.
  • REFRIGERATION CYCLE DEVICE 2 REFRIGERATION CYCLE CIRCUIT 3 3A 3B 3C CONTROL DEVICE 4
  • COMPRESSOR 401 SUCTION PIPE 402 DISCHARGE PIPE 5
  • Expansion valve 7 Second heat exchanger (condenser, evaporator) 9
  • Accumulator 10 Power source 11 Discharge port 20 Working medium 31 Drive circuit 32 State detection circuit 33 First protection device 34 Second protection device 35 Control circuit 36, 36A, 36B Switching device 311 Converter circuit 312 Inverter circuit

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WO2012157765A1 (ja) 2011-05-19 2012-11-22 旭硝子株式会社 作動媒体および熱サイクルシステム
WO2012157764A1 (ja) 2011-05-19 2012-11-22 旭硝子株式会社 作動媒体および熱サイクルシステム
WO2015140871A1 (ja) * 2014-03-17 2015-09-24 三菱電機株式会社 冷凍サイクル装置
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WO2016199396A1 (ja) * 2015-06-11 2016-12-15 パナソニックＩｐマネジメント株式会社 冷凍サイクル装置
JP2018177967A (ja) * 2017-04-13 2018-11-15 パナソニックＩｐマネジメント株式会社 冷凍サイクル装置
JP2019152380A (ja) 2018-03-05 2019-09-12 パナソニックＩｐマネジメント株式会社 冷凍サイクル装置
JP2020169782A (ja) * 2019-04-05 2020-10-15 パナソニックＩｐマネジメント株式会社 冷凍サイクル装置

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Publication number Priority date Publication date Assignee Title
WO2012157765A1 (ja) 2011-05-19 2012-11-22 旭硝子株式会社 作動媒体および熱サイクルシステム
WO2012157764A1 (ja) 2011-05-19 2012-11-22 旭硝子株式会社 作動媒体および熱サイクルシステム
WO2015140871A1 (ja) * 2014-03-17 2015-09-24 三菱電機株式会社 冷凍サイクル装置
WO2015174054A1 (ja) * 2014-05-12 2015-11-19 パナソニックＩｐマネジメント株式会社 冷凍サイクル装置
WO2016199396A1 (ja) * 2015-06-11 2016-12-15 パナソニックＩｐマネジメント株式会社 冷凍サイクル装置
JP2018177967A (ja) * 2017-04-13 2018-11-15 パナソニックＩｐマネジメント株式会社 冷凍サイクル装置
JP2019152380A (ja) 2018-03-05 2019-09-12 パナソニックＩｐマネジメント株式会社 冷凍サイクル装置
JP2020169782A (ja) * 2019-04-05 2020-10-15 パナソニックＩｐマネジメント株式会社 冷凍サイクル装置

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