WO2022176148A1 - 冷凍サイクル装置 - Google Patents

冷凍サイクル装置 Download PDF

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Publication number
WO2022176148A1
WO2022176148A1 PCT/JP2021/006293 JP2021006293W WO2022176148A1 WO 2022176148 A1 WO2022176148 A1 WO 2022176148A1 JP 2021006293 W JP2021006293 W JP 2021006293W WO 2022176148 A1 WO2022176148 A1 WO 2022176148A1
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WO
WIPO (PCT)
Prior art keywords
motor
control mode
compressor
inverter
speed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2021/006293
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English (en)
French (fr)
Japanese (ja)
Inventor
和憲 坂廼邉
健吾 柿森
朱音 本行
晃弘 津村
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Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to GB2311846.6A priority Critical patent/GB2618019B/en
Priority to US18/259,097 priority patent/US20240053071A1/en
Priority to PCT/JP2021/006293 priority patent/WO2022176148A1/ja
Priority to JP2023500450A priority patent/JP7479560B2/ja
Publication of WO2022176148A1 publication Critical patent/WO2022176148A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • 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
    • F25B49/025—Motor control arrangements
    • 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
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
    • 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
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • F25B47/022—Defrosting cycles hot gas defrosting
    • F25B47/025—Defrosting cycles hot gas defrosting by reversing the 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
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/021—Inverters therefor
    • 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
    • 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
    • F25B2700/21—Temperatures
    • F25B2700/2115—Temperatures of a compressor or the drive means therefor
    • F25B2700/21152—Temperatures of a compressor or the drive means therefor at the discharge side of the compressor
    • 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
    • F25B31/00—Compressor arrangements
    • F25B31/02—Compressor arrangements of motor-compressor units
    • F25B31/026—Compressor arrangements of motor-compressor units with compressor of rotary type

Definitions

  • the present disclosure relates to a refrigeration cycle device.
  • the heat source side heat exchanger is heated during operation to recover the reduction in refrigerating capacity or air conditioning capacity that occurs when frost forms on the heat source side heat exchanger that functions as an evaporator.
  • a melting defrost operation is performed. In the defrosting operation, heat energy is consumed in the heat source side heat exchanger to heat the heat source side heat exchanger.
  • Patent Literature 1 discloses a method of heating a refrigerant by a power conversion device that supplies power to a compressor in order to prevent liquid backflow during defrosting operation.
  • the refrigerating cycle apparatus functions as a heat pump that lowers the temperature using the heat source side heat exchanger as an evaporator and raises the temperature using the use side heat exchanger as the condenser during heating operation, for example. . Therefore, the defrosting operation that lowers the temperature of the heat exchanger on the user side temporarily reduces the function of the heat pump, which is not desirable for users. Therefore, it is desired that the defrosting operation is as short as possible and the temperature change is small.
  • Patent Document 1 is a method of heating a power converter in order to prevent a special environmental condition such as a liquid backflow phenomenon during defrosting operation. is not intended to improve
  • the present disclosure has been made to solve the above problems, and aims to provide a refrigeration cycle device capable of shortening the time period during which the heating capacity is reduced due to defrosting.
  • the present disclosure relates to a refrigeration cycle device.
  • the refrigeration cycle device includes a compressor, an outdoor heat exchanger, a throttle device, an indoor heat exchanger, and a four-way valve, a refrigerant circuit configured to circulate refrigerant, and an inverter for variable speed control of the compressor. , and a temperature sensor for measuring the temperature of the compressor.
  • the refrigerant circuit is configured to perform a defrosting operation in which the refrigerant discharged from the compressor is introduced into the outdoor heat exchanger by switching the direction of the four-way valve.
  • the compressor includes a compression section and a motor that drives the compression section.
  • the inverter has two operation modes: a speed control mode in which the motor is controlled so as to approach the rotational speed corresponding to the command value; It has an output control mode to control.
  • the refrigeration cycle device it is possible to selectively use the speed control mode and the output control mode. Therefore, it is possible to shorten the time during which the heating capacity is reduced due to defrosting.
  • FIG. 1 is a circuit configuration diagram of a refrigeration cycle device 100 according to Embodiment 1.
  • FIG. FIG. 4 is a diagram showing the direction of refrigerant flow during defrosting.
  • 2 is a cross-sectional view showing the structure of the compressor 1;
  • FIG. 2 is a functional block diagram showing a configuration example of an inverter 20;
  • FIG. 3 is a diagram showing a configuration of a control device 15;
  • FIG. 4 is a diagram showing a configuration of a control circuit 41;
  • FIG. FIG. 4 is a diagram for explaining operations in an output control mode;
  • FIG. 4 is a flow chart showing a method of controlling operation modes during heating and defrosting operations in the control device 15.
  • FIG. 4 is a time chart showing the operation of the refrigeration cycle apparatus 100 according to Embodiment 1;
  • FIG. 4 is a time chart showing the operation of the refrigeration cycle apparatus 100 according to Embodiment 1;
  • FIG. 4 is a time chart showing the operation of the refrigeration cycle apparatus 100 according
  • FIG. 5 is a functional block diagram showing a modification of the inverter of FIG. 4;
  • 1 is a cross-sectional view of an embedded magnet motor for a compressor;
  • FIG. FIG. 4 is a diagram showing stress applied to a rotor core thin portion;
  • FIG. 4 is a diagram showing the relationship between the rotational speed of a compressor motor and the stress of a bridge portion;
  • FIG. 4 is a diagram showing the relationship between frequency, voltage, and current output from an inverter;
  • FIG. 13 is a diagram showing a configuration of a speed control unit 52 applied to Embodiment 4;
  • FIG. 1 is a circuit configuration diagram of a refrigeration cycle apparatus 100 according to Embodiment 1.
  • the refrigeration cycle device 100 includes an outdoor unit 103 and an indoor unit 104 .
  • the outdoor unit 103 and the indoor unit 104 are connected by extension pipes 101 and 102 .
  • the refrigeration cycle device 100 includes a refrigerant circuit 105 , an inverter 20 , a control device 15 and a temperature sensor 30 .
  • the refrigerant circuit 105 includes a compressor 1, an outdoor heat exchanger 2, an expansion device 3, an indoor heat exchanger 4, a four-way valve 5, and an accumulator 6, which are connected by pipes, and is configured to circulate the refrigerant. be.
  • the compressor 1 sucks in the refrigerant, compresses it, and discharges it in a state of high temperature and high pressure.
  • the compressor 1 incorporates a compression mechanism section 12 and a motor 11 .
  • the motor 11 generates power for driving the compression mechanism section 12 of the compressor 1 .
  • Motor 11 is electrically connected to inverter 20 .
  • the motor 11 is driven and controlled by an inverter 20 .
  • FIG. 3 is a cross-sectional view showing the structure of the compressor 1.
  • FIG. Compressor 1 includes housing 13 , motor 11 , and compression mechanism section 12 .
  • the compressor 1 sucks in the refrigerant from the suction pipe 1b, compresses it, and discharges it from the discharge pipe 1a in a state of high temperature and high pressure.
  • a housing 13 of the compressor 1 accommodates a compression mechanism section 12 and a motor 11 .
  • the motor 11 has a winding 11a and an iron core 11b that are in contact with the refrigerant sucked from the suction pipe 1b.
  • the winding 11a and the iron core 11b are configured to receive thermal energy between themselves and the refrigerant.
  • the outdoor heat exchanger 2 and the indoor heat exchanger 4 exchange heat between a refrigerant and a heat medium such as air.
  • a heat medium such as air.
  • fin-tube heat exchangers can be used as the outdoor heat exchanger 2 and the indoor heat exchanger 4.
  • the outdoor heat exchanger 2 When the refrigeration cycle device 100 is in cooling operation, the outdoor heat exchanger 2 functions as a condenser.
  • the outdoor heat exchanger 2 functions as an evaporator when the refrigeration cycle device 100 is in heating operation.
  • the expansion device 3 expands and decompresses the refrigerant.
  • the throttle device 3 is, for example, a device such as an electronic expansion valve whose opening degree can be arbitrarily controlled.
  • the opening degree of the diaphragm device 3 is controlled by the control device 15, for example.
  • the expansion device 3 is connected between the outdoor heat exchanger 2 and the indoor heat exchanger 4 .
  • the expansion device 3 functions as an evaporator by converting the refrigerant flowing out of either the outdoor heat exchanger 2 or the indoor heat exchanger 4, which functions as a condenser, into a low-temperature and low-pressure state. flow into the other heat exchanger.
  • the refrigerant flowing out of the outdoor heat exchanger 2 flows into the expansion device 3 and enters the indoor heat exchanger 4 while being in a low temperature and low pressure state.
  • the four-way valve 5 has a function of switching between the refrigerant flow direction during heating and the refrigerant flow direction during cooling.
  • the operation of the four-way valve 5 is controlled by a controller 15, for example.
  • the four-way valve 5 switches the flow path of the refrigerant so that the discharge side of the compressor 1 is connected to the heat exchanger functioning as a condenser, out of the outdoor heat exchanger 2 and the indoor heat exchanger 4 .
  • the accumulator 6 stores surplus refrigerant.
  • FIG. 2 is a diagram showing the direction of refrigerant flow during defrosting.
  • the control device 15 includes a mode determination unit 22 that determines whether the operation mode of the inverter 20 should be the speed control mode or the output control mode based on the current operating state (normal operation or defrosting operation); and a refrigeration cycle control unit 23 that generates a speed command value for the machine 1 .
  • the operating speed (rps) of the compressor 1 is often represented by the frequency (Hz), so the speed command value is also called the frequency command value.
  • a temperature sensor 30 detects the temperature of the refrigerant discharged from the compressor 1 .
  • the temperature sensor 30 is attached to the discharge pipe 1a of the compressor 1, for example. Information on the temperature measured by the temperature sensor 30 is input to the mode determination unit 22 of the control device 15 .
  • FIG. 4 is a functional block diagram showing a configuration example of the inverter 20. As shown in FIG.
  • the inverter 20 includes a control circuit 41 and a power converter 40 .
  • the control circuit 41 receives a speed command value ⁇ * 1 from the external host controller 15, receives current detection signals Iu and Iw detected by the current sensors 42a and 42b, and outputs a three-phase voltage command value to the power converter 40. Output Vuvw*.
  • the control circuit 41 includes an output control section 21 , a selector 61 , a dq conversion section 50 , a speed estimation section 51 , a speed control section 52 and a dq inverse conversion section 55 .
  • the inverter 20 is provided with an output control unit 21 that controls the output power to be substantially constant.
  • the dq conversion unit 50 generates a d-axis current value Id and a q-axis current value Iq based on the current detection signals Iu and Iw and the phase estimation value ⁇ .
  • the speed estimator 51 generates a speed estimated value ⁇ est based on the d-axis voltage command value Vd*, the q-axis voltage command value Vq*, the d-axis current value Id, and the q-axis current value Iq.
  • a speed control unit 52 generates a d-axis voltage command value Vd* and a q-axis voltage command value Vq* based on a speed command value ⁇ *, an estimated speed value ⁇ est , a d-axis current value Id, and a q-axis current value Iq. do.
  • the dq inverse conversion unit 55 generates a three-phase voltage command value Vuvw* based on the d-axis voltage command value Vd* and the q-axis voltage command value Vq*, and outputs the three-phase voltage command value Vuvw* to the power conversion unit 40. to perform PWM control.
  • FIG. 5 is a diagram showing the configuration of the control device 15. As shown in FIG. In FIGS. 1, 2 and 4, the control device 15 includes the mode determination section 22 and the refrigeration cycle control section 23 as functional blocks, but the actual hardware configuration includes, for example, a microcomputer.
  • the control device 15 includes a CPU (Central Processing Unit) 151, a memory (ROM (Read Only Memory) and RAM (Random Access Memory)) 152, and an input/output device (not shown) for inputting various signals. etc.
  • the CPU 151 expands a program stored in the ROM into the RAM or the like and executes it.
  • the program stored in the ROM is a program in which processing procedures of the control device 15 are described.
  • the control device 15 executes control of the refrigeration cycle device according to these programs. That is, CPU 151 executes processing corresponding to mode determination unit 22 and refrigeration cycle control unit 23 according to a program stored in memory 152 .
  • This processing is not limited to processing by software, and processing by dedicated hardware (electronic circuit) is also possible.
  • FIG. 6 is a diagram showing the configuration of the control circuit 41.
  • the control circuit 41 includes the output control section 21, the selector 61, the speed control section 52, the speed estimation section 51, the dq inverse conversion section 55, and the dq conversion section 50 as functional blocks.
  • the hardware configuration includes, for example, a microcomputer.
  • the control circuit 41 includes a CPU 411, a memory (ROM and RAM) 412, and an input/output device (not shown) for inputting various signals.
  • the CPU 411 expands the program stored in the ROM into the RAM or the like and executes it.
  • the program stored in the ROM is a program in which processing procedures of the control circuit 41 are described.
  • the control circuit 41 executes PWM control of the inverter according to these programs. That is, the CPU 411 executes processing corresponding to the output control section 21 , the selector 61 , the speed control section 52 , the speed estimation section 51 , the dq inverse conversion section 55 and the dq conversion section 50 according to the programs stored in the memory 412 .
  • This processing is not limited to processing by software, and processing by dedicated hardware (electronic circuit) is also possible.
  • Each functional block may be one control unit controlled by the same CPU, or may be separate control units controlled by different CPUs.
  • Inverter 20 operates based on operation mode MODE determined by control device 15 .
  • the selector 61 is set so that the speed command value ⁇ * 1 of the compressor 1 becomes the speed command value ⁇ * given to the speed control section 52 .
  • the inverter 20 controls the output frequency based on the speed command value ⁇ * 1 , and also controls the three-phase voltage command value Vuvw* so that the losses of the inverter 20 and the motor 11 are substantially minimized. As a result, efficient operation is normally performed.
  • the output control unit 21 in the inverter 20 sequentially calculates the output (electric power) P of the motor 11 and the upper limit value P* of the output P, and controls the speed command value so that the output P approaches P*. Controls ⁇ * 2 .
  • the selector 61 is set so that the speed command value ⁇ * 2 becomes the speed command value ⁇ * given to the speed controller 52 .
  • P* is a power command value, but here, an example in which the maximum value Pmax is adopted so as to expand the operating range will be described.
  • the maximum value Pmax is the maximum value of the output power uniquely determined by the motor constant representing the characteristics of the motor and the DC voltage Vdc.
  • the output P and the speed command value ⁇ * 2 are calculated, for example, by the following equations (1) and (2).
  • k is a constant
  • ⁇ is a rotation speed
  • Iq is a torque current.
  • P k ⁇ Iq (1)
  • ⁇ * 2 P*/Iq/k (2)
  • Tmax [Nm] is the upper limit value of the mechanical torque of the compressor 1
  • fmax is the maximum frequency at the upper torque limit.
  • the areas of two hatched squares with points B and B' as vertices indicate the magnitude of motor output. In heating and defrosting operations, high motor output corresponds to high heating and defrosting capacity.
  • the output control mode the motor 11 is controlled to increase the speed so that the output Pmax is maintained, so the operating point moves to point B and the output of the motor 11 does not change. That is, the output control mode is an operation mode in which deterioration of the defrosting ability or the heating ability due to changes such as temperature reduction, pressure reduction, and dryness reduction of the refrigerant sucked by the compressor 1 is unlikely to occur.
  • FIG. 8 is a flow chart showing a method of controlling operation modes during heating and defrosting operations in the control device 15 .
  • a step is abbreviated as S hereinafter. If the current operating state is defrosting (YES in S1) and a certain period of time has passed since the start of defrosting (YES in S2), the control device 15 sets the operating mode to the output control mode ( S4).
  • the operating mode is similarly set to the output control mode (S4).
  • the control device 15 sets the operating mode to the speed control mode. (S5).
  • the operating mode is set to the speed control mode (S5).
  • FIG. 9 is a time chart showing the operation of the refrigeration cycle apparatus 100 according to Embodiment 1.
  • FIG. The operation of this embodiment will be described with reference to solid-line waveforms T1 and F1.
  • the controller 15 switches the four-way valve 5 as shown at time tA so that the destination of the gas discharged from the compressor 1 is changed from the indoor heat exchanger 4 to the outdoor heat exchanger 2 when performing the defrosting operation.
  • the flow direction of the coolant is changed from the direction shown in FIG. 1 to the direction shown in FIG.
  • the gas discharged from the compressor 1 is at high temperature and high pressure.
  • the high-temperature refrigerant flows into the frosted outdoor heat exchanger 2 and is cooled and decompressed. Therefore, if the defrosting operation is continued, the temperature and pressure of the refrigerant sucked into the compressor 1 also decrease as indicated by waveform T1, and accordingly the discharge temperature decreases as indicated at time tB.
  • the control device 15 detects a drop in the discharge temperature indicated by the waveform T1 and switches the operation mode of the inverter 20 from the speed control mode to the output control mode.
  • the load torque of the compressor 1 is also high. Therefore, in the output control mode, in inverter 20, speed command value ⁇ * 2 is set to a relatively low value.
  • high-temperature refrigerant for defrosting flows into the outdoor heat exchanger 2, but heat is taken away by the frost, so the temperature of the refrigerant drops at the outlet of the heat exchanger.
  • the indoor heat exchanger 4 is controlled so as not to exchange heat by stopping air blowing, etc. As a result, the thermal energy and pressure in the entire refrigerant circuit 105 connected by the refrigerant pipes are reduced. Along with this, the load torque for operating the compressor 1 also decreases.
  • the output control unit 21 detects the q-axis current, recognizes this decrease in load torque, and increases the speed command value ⁇ * 2 based on equation (2). Due to the increase in rotation speed, the flow velocity of the refrigerant in the refrigerant circuit 105 during defrosting operation increases, the flow path pressure loss increases according to the flow velocity, and the heat energy of the refrigerant, that is, the temperature and pressure rises according to the pressure loss. As a result, the defrosting capacity of the outdoor heat exchanger 2 is increased. By repeating the above operations, the defrosting can be completed quickly (time tC in FIG. 9).
  • the time charts in the case of controlling only in the speed control mode are shown in broken-line waveforms T2 and F2 in FIG.
  • the operating frequency is not increased as the discharge temperature decreases during defrosting. Therefore, the defrosting time (time tB to tC') is long, and the temperature recovery of the refrigerant after switching to heating is slow, so the discharge temperature does not rise. Therefore, as shown by the waveform T2 from time tC' to tD', the indoor temperature drop state is not resolved for a long time.
  • the defrosting time of the refrigerating cycle device and the heating start-up time are lengthened, and the user's comfort is impaired.
  • Embodiment 2 is a functional block diagram showing a modification of the inverter in FIG. 4.
  • FIG. 10 is a functional block diagram showing a modification of the inverter in FIG. 4.
  • the inverter 20A shown in FIG. 10 includes a control circuit 41A and a power converter 40.
  • Control circuit 41A includes a minimum value selection section 120 and a speed upper limit calculation section 121 instead of output control section 21 and selector 61 in the configuration of control circuit 41 shown in FIG.
  • Other structures of control circuit 41A are the same as those of control circuit 41 shown in FIG. 4, and description thereof will not be repeated.
  • the speed upper limit calculator 121 calculates the rotational speed upper limit value ⁇ max based on the following equations (3) and (4).
  • Te indicates the output torque
  • Pmax indicates the maximum output torque.
  • the minimum value selector 120 compares the speed control mode command value ⁇ * 1 with the output control mode rotational speed upper limit value ⁇ max , and outputs the smaller one as the actual control speed command value ⁇ *.
  • the minimum value selector 120 enables automatic switching between the output control mode and the speed control mode, eliminating the need for additional control signals from the controller 15 .
  • a rotation speed sufficiently higher than the rotation speed upper limit value ⁇ max may be specified. Then, since the speed command value ⁇ * is set to the rotation speed upper limit value ⁇ max , the operation mode of the inverter 20A becomes the output control mode.
  • FIG. 11 is a cross-sectional view of an embedded magnet motor for a compressor.
  • FIG. 12 is a diagram showing the stress applied to the thin portion of the rotor core.
  • the motor 11 includes a rotor 66 and a stator 67.
  • Rotor 66 of motor 11 includes a plurality of permanent magnets 71 and an iron core (rotor core) 70 .
  • Stator 67 includes an iron core (stator core) 73 and windings 74 of a coil.
  • the iron core 70 extends in the radial direction on the q-axis positioned between adjacent magnets 71A and 71B among the plurality of permanent magnets 71, and holds the positions of the adjacent magnets 71A and 71B. It has a bridge portion 72A for conducting.
  • IPMSM Interior Permanent Magnet Synchronous Motor
  • the maximum rotational speed of a compressor is specified by the operating frequency (fnom) corresponding to the rotational speed at which the maximum rated capacity is exhibited.
  • the control command value in the output control mode is a fixed value (Pmax). An improvement in defrosting performance is realized.
  • the stress F has a device-specific maximum value Fmax based on the mechanical strength of the rotor.
  • F Fmax
  • the maximum rated torque is defined as TL max
  • the angular velocity under the conditions of TL TL max
  • FIG. 13 shows a relational diagram between the rotational speed of the compressor motor and the stress of the bridge portion.
  • the load torque T L is a function of the refrigerant gas pressure, and the lower the pressure, the smaller the load torque.
  • the load torque during defrosting is defined as T L def
  • the maximum angular velocity is defined as ⁇ def.
  • Embodiments 1 and 2 high-speed operation is performed during defrosting operation, which is an operating state in which the load torque is small, so it is clear that the stress on the rotor core does not excessively increase. That is, in the third embodiment, it is possible to provide a compressor that reduces the defrosting time by speeding up and reduces the burden of strength against breakage due to an increase in centrifugal force.
  • Embodiment 4 At the time of defrosting, there is a possibility that the refrigerant cooled and liquefied in the outdoor heat exchanger 2 reaches the compressor (hereinafter referred to as liquid bag). Liquid backflow causes the lubricating oil inside the compressor to foam and causes poor lubrication. is concerned. A method for coping with the liquid back will be described below with reference to FIG. 14 .
  • FIG. 14 is a diagram showing the relationship between the frequency output by the inverter and the voltage and current.
  • the solid line indicates the output voltage
  • the dashed-dotted line indicates the current.
  • fmax is the maximum rated frequency
  • Vmax is the maximum value of the output voltage
  • fnom is the maximum frequency at which operation can be performed with maximum efficiency.
  • the inverter is made to output a voltage (Vmax- ⁇ V) lower than the maximum value Vmax.
  • Vmax- ⁇ V the current increases from Ib to Ic, and the motor heats up as the current increases.
  • FIG. 15 is a diagram showing the configuration of the speed control unit 52 applied to the fourth embodiment.
  • the speed controller 52 shown in FIG. 15 is used as the speed controller 52 in FIG. 4 or FIG.
  • Speed controller 52 includes q-axis current command calculator 110, d-axis current command calculator 111, voltage command calculator 112, phase calculator 113, and subtractors 114-116.
  • the control device 15 includes a heating determination unit 117 that controls ON/OFF of heating control based on the compressor discharge temperature Td and the operation mode MODE.
  • HEAT indicates a heating control signal given from the heating judgment section 117 in the control device 15 .
  • the heating determination unit 117 monitors the compressor discharge temperature Td and the operation mode MODE. When the operation mode is the output control mode and the discharge temperature Td is equal to or lower than the determination temperature, it is determined that the compressor needs to be heated, and the heating determination unit 117 sets the heating control signal to ON. Otherwise, the heating determination unit 117 sets the heating control signal to OFF.
  • the d-axis current command calculator outputs a d-axis current command Id* according to normal d-axis current control when the externally applied heating control signal HEAT is OFF.
  • R is the phase resistance
  • Ld is the d-axis inductance
  • Lq is the q-axis inductance
  • ⁇ f is the induced voltage constant
  • ⁇ is the electrical angular velocity
  • Id* is the d-axis current command
  • Iq* is the q-axis current command.
  • Id* is determined according to the following equation (10).
  • Imax indicates the maximum current rating.
  • the maximum rated current value Imax is a value unique to the motor determined by the demagnetization current limit. That is, the current is controlled at the maximum rated current value Imax, which is the maximum allowable current value of the motor. As a result, motor loss increases and heat generation can be increased.
  • Id* is set to a negative value. This is because the d-axis current command cannot be increased at the upper voltage limit of the inverter. Heating is also possible with positive values.
  • the current limit is determined by the demagnetization current limit. However, if the current rating of the inverter or the step-out limit of the motor is lower than the demagnetization current limit, the motor can be controlled by setting these as upper limits. good.
  • the refrigeration cycle apparatus by performing control to increase the frequency of the compressor, the pressure loss in the refrigerant circuit and the mechanical loss, iron loss, and copper loss of the compressor increase, respectively, and the refrigerant temperature or A rise in the refrigerant pressure is facilitated. Therefore, the defrosting operation of the outdoor heat exchanger can be completed early, and the time during which the heating capacity of the indoor heat exchanger is reduced after the defrosting operation can be shortened.
  • shortening the defrosting time is effective not only in eliminating the user's feeling of cold air during heating operation, but also in improving the average heating capacity.
  • Refrigeration cycle apparatus 100 of the present embodiment shown in FIG. 1 includes refrigerant circuit 105 and inverter 20 .
  • a refrigerant circuit 105 includes a compressor 1, an outdoor heat exchanger 2, an expansion device 3, an indoor heat exchanger 4, and a four-way valve 5, and is configured to circulate refrigerant.
  • Inverter 20 is configured to perform variable speed control of compressor 1 .
  • Refrigerant circuit 105 is configured to enable defrosting operation in which refrigerant discharged from compressor 1 is introduced into outdoor heat exchanger 2 as shown in FIG. 2 by switching four-way valve 5 .
  • the compressor 1 includes a compression mechanism section 12 and a motor 11 that drives the compression mechanism section 12 .
  • the inverter 20 has two operation modes: a speed control mode in which the motor 11 is controlled so as to approach the rotational speed corresponding to the command value; and an output control mode for controlling 11 rotational speeds.
  • the inverter 20 is configured to be able to operate using the output control mode in the defrosting operation. As a result, it is possible to provide a refrigeration cycle apparatus capable of shortening the defrosting time, which is a weak point of heat pumps.
  • the value indicated by the externally given command value ⁇ * 1 is the rotational speed upper limit determined by the DC voltage of the inverter 20, the characteristic value of the motor 11, and the current of the motor 11. It is used when ⁇ max is exceeded. Therefore, since the output control mode is applied only with the command value ⁇ * 1 given from the outside, it is possible to provide a refrigeration cycle apparatus with excellent feasibility with few interface changes.
  • the operation mode is set to the speed control mode during the defrosting operation (YES at S1), at the start of defrosting (S5), and after a certain period of time has elapsed from the start of defrosting (YES at S2). , the speed control mode is switched to the output control mode (S4).
  • the refrigerating cycle device 100 shown in FIG. 1 further includes a temperature sensor 30 that measures the discharge temperature Td of the refrigerant discharged from the compressor 1 .
  • a temperature sensor 30 that measures the discharge temperature Td of the refrigerant discharged from the compressor 1 .
  • the operation mode is set to the speed control mode (S5), and the discharge temperature Td of the compressor 1 is set to If it is lower than the judgment value (YES in S3), the output control mode is set (S4).
  • the rotor 66 of the motor 11 includes a plurality of permanent magnets 71 and an iron core 70.
  • the iron core 70 extends in the radial direction on the q-axis positioned between adjacent magnets 71A and 71B among the plurality of permanent magnets 71, and holds the positions of the adjacent magnets 71A and 71B. It has a bridge portion 72A for conducting.
  • the inverter 20 has a d-axis current command calculator 111 that controls the amplitude and phase of the current of the motor 11 .
  • the d-axis current command calculator 111 controls the current command value Id* so that the current of the motor 11 reaches the maximum rated value Imax during the output control mode.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Conditioning Control Device (AREA)
  • Control Of Ac Motors In General (AREA)
PCT/JP2021/006293 2021-02-19 2021-02-19 冷凍サイクル装置 Ceased WO2022176148A1 (ja)

Priority Applications (4)

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GB2311846.6A GB2618019B (en) 2021-02-19 2021-02-19 Refrigeration cycle apparatus
US18/259,097 US20240053071A1 (en) 2021-02-19 2021-02-19 Refrigeration cycle apparatus
PCT/JP2021/006293 WO2022176148A1 (ja) 2021-02-19 2021-02-19 冷凍サイクル装置
JP2023500450A JP7479560B2 (ja) 2021-02-19 2021-02-19 冷凍サイクル装置

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JPH06265244A (ja) * 1993-03-15 1994-09-20 Toshiba Corp 空気調和機
JP2006191775A (ja) * 2005-01-07 2006-07-20 Mitsubishi Electric Corp 電動機装置
JP2010008003A (ja) * 2008-06-30 2010-01-14 Hitachi Appliances Inc 空気調和器
WO2020008620A1 (ja) * 2018-07-06 2020-01-09 三菱電機株式会社 冷凍サイクル装置および空気調和装置

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US5559419A (en) * 1993-12-22 1996-09-24 Wisconsin Alumni Research Foundation Method and apparatus for transducerless flux estimation in drives for induction machines
JP2001008003A (ja) * 1999-06-18 2001-01-12 Canon Inc 画像読取装置及び画像形成装置
JP2003222391A (ja) * 2002-01-29 2003-08-08 Daikin Ind Ltd ヒートポンプ式給湯機
WO2009041075A1 (ja) * 2007-09-28 2009-04-02 Daikin Industries, Ltd. 圧縮機の運転制御装置及びそれを備えた空気調和装置
US9121628B2 (en) * 2009-06-02 2015-09-01 Nortek Global Hvac Llc Heat pumps with unequal cooling and heating capacities for climates where demand for cooling and heating are unequal, and method of adapting and distributing such heat pumps
JP5984965B2 (ja) * 2012-12-11 2016-09-06 三菱電機株式会社 空調給湯複合システム
WO2020021681A1 (ja) * 2018-07-26 2020-01-30 三菱電機株式会社 電動機駆動装置及び冷凍サイクル適用機器

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06265244A (ja) * 1993-03-15 1994-09-20 Toshiba Corp 空気調和機
JP2006191775A (ja) * 2005-01-07 2006-07-20 Mitsubishi Electric Corp 電動機装置
JP2010008003A (ja) * 2008-06-30 2010-01-14 Hitachi Appliances Inc 空気調和器
WO2020008620A1 (ja) * 2018-07-06 2020-01-09 三菱電機株式会社 冷凍サイクル装置および空気調和装置

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JP7479560B2 (ja) 2024-05-08
GB2618019B (en) 2024-12-11

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