Heat pump unit, heat pump system, air conditioning and refrigeration machine

Abstract

Heat pump device (100), comprising: a compressor (1) comprising a compression device (7) which compresses a refrigerant and a motor (8) which drives the compression device (7); an inverter (103) which applies a desired voltage to the motor (8); an inverter controller (104) which controls the inverter (103); a control power supply generating circuit (105) which supplies control power to the inverter (103) and the inverter controller (104); a high pressure switch (107) which switches when an output pressure of the compressor (1) reaches a preset pressure or more; and a heat switch (108) which switches when a temperature of the compressor (1) reaches a preset temperature or more, wherein the high-pressure switch (107) and the thermal switch (108) are installed on a power supply line for supplying power to the inverter (103), are connected in series via a line, and are connected via a single connector to a control board (9) on which at least one of the inverter controller (104) and the control power supply generation circuit (105) is mounted, and wherein the high pressure switch (107) is opened when the discharge pressure of the compressor (1) reaches the preset pressure or more, or the thermal switch (108) is opened when the temperature of the compressor (1) reaches the preset temperature or more to interrupt a power supply to the inverter (103).

Description

AreaThe present disclosure relates to a heat pump apparatus including a compressor, a heat pump system, an air conditioner, and a chiller.BackgroundIn air conditioners having driving circuits for driving compressors, protection of loads such as the compressors from abnormal overheating has been provided. Patent Literature 1 teaches a technology for protecting a load against abnormal overheating in an air conditioner by detecting a case temperature of the load as voltage information and controlling supply of a control voltage to a drive controller based on a result of comparison between the detected value and a threshold voltage. Patent Literature 2 discloses an air conditioner in which, when an abnormality occurs, either an overheat protection relay or a high-pressure switch is operated to transmit an abnormality signal from an abnormality detector to an abnormality content identifier. The abnormality content identifier 16 reads a detected value of the pressure switch 15. a red LED indicating that the high pressure switch has been operated lights up when the read value is a predetermined value or more. A green LED indicating that the overheat protection relay is operated lights when the read value is the predetermined value or less. Patent Literature 3 discloses a protection device for an air conditioner capable of positively stopping the operation of a compressor in an abnormal state and further detecting an abnormal location. The protection device comprises a plurality of protection switching means including an overheat protection switching means for a blower, an overheat protection switching means for a compressor, and a high pressure switching means for operating a solenoid valve are electrically connected in series with each other. An energizing means of a compressor-operated electromagnetic switching means is electrically connected in series therewith. As soon as one of the protective switching means is actuated, the energy supply means is shielded. In the case that one of the circuit breakers is operated, a recovery time of the operated circuit breaker means is calculated and then the discriminating means judges which circuit breaker means is operated in response to a difference of the calculated recovery time between the circuit breaker means from each other.Citing listPatent LiteraturePatent Literature 1: WO 2019 / 123 545 A1Patent Literature 2: JP H07-19 679 APatent Literature 3: JP H09-14 805 ABrief Description of the InventionTechnical ProblemHowever, according to the aforementioned conventional technology, a protection circuit is composed of a combination of a plurality of circuits such as a thermistor input circuit, a comparison circuit, and a control voltage interrupt circuit. This is problematic in that the number of components increases, the board component area therefore increases, and the size of the device increases. Further, malfunction due to noise is more likely to be caused, and reliability may decrease.The present disclosure has been made in view of the above, and its object is to provide a heat pump apparatus capable of performing a protected operation while reducing or preventing an increase in size of the apparatus and reducing or preventing a malfunction due to noise.Solution of the ProblemIn order to solve the above problem and achieve an object, a heat pump apparatus according to the present disclosure includes: a compressor including a compressor that compresses a refrigerant and a motor that drives the compressor; an inverter that applies a desired voltage to the motor; an inverter controller that controls the inverter; a high-pressure switch that switches when an output pressure of the compressor reaches a preset pressure or more; a thermal switch that switches when a temperature of the compressor reaches a preset temperature or more, wherein the high-pressure switch and the thermal switch are installed on a power supply line for supplying power to the inverter, and the high-pressure switch is opened when the output pressure of the compressor reaches the preset pressure or more, or the thermal switch is opened when the temperature of the compressor reaches the preset temperature or more, to cut off power supply to the inverter.Advantageous Effects of the InventionA heat pump apparatus according to the present disclosure enables protected operation while reducing or preventing an increase in size of the apparatus and thereby reducing or preventing malfunction due to noise.Brief Description of DrawingsFIG. 1 is a diagram showing an example of a configuration of a heat pump apparatus according to a first embodiment. FIG. 2 is a diagram showing a circuit configuration of a control board included in the heat pump apparatus according to the first embodiment. FIG. 3 is a graph showing an example of a time change of a casing temperature, an outside air temperature, and a refrigerant storage amount of a compressor of the heat pump apparatus according to the first embodiment. FIG. 4 is a diagram showing an example of a hardware configuration for implementing inverter control of the control board included in the heat pump apparatus according to the first embodiment. FIG. 5 is a diagram showing a circuit configuration of a control board included in a heat pump apparatus according to a second embodiment. FIG. 6 is a flowchart showing the operation of a system controller included in the heat pump apparatus according to the second embodiment. FIG. 7 is a diagram showing an example of a configuration of a heat pump system including a heat pump apparatus according to a third embodiment. FIG. 8 is a Mollier diagram of the state of a refrigerant in the heat pump apparatus according to the third embodiment.DESCRIPTION OF EMBODIMENTSA heat pump apparatus, a heat pump system, an air conditioner, and a chiller according to certain embodiments of the present disclosure will be described below in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments.First Embodiment.FIG. 1 is a diagram showing an example of a configuration of a heat pump apparatus 100 according to a first embodiment. As shown in FIG. 1, the heat pump apparatus 100 includes a refrigeration cycle in which a compressor 1, a four-way valve 2, a heat exchanger 3, an expander 4, and a heat exchanger 5 are connected in series via a refrigerant pipe 6. The compressor 1 includes a compressor 7 for compressing a refrigerant and a motor 8 for driving the compressor 7. the motor 8 is a three-phase motor having three-phase lines of U-phase, V-phase and W-phase.A control board 9 is electrically connected to the motor 8 and applies a voltage to the motor 8 to drive the motor 8. The control board 9 uses an AC voltage Vac supplied from an AC power source 10 as a power supply to generate and apply three-phase voltages Vu, Vv, and Vw to be supplied to the U-phase, V-phase, and W-phase lines of the motor 8.FIG. 2 is a diagram showing a circuit configuration of the control board 9 included in the heat pump apparatus 100 according to the first embodiment. The control board 9 includes a rectifier 101, a smoothing capacitor 102, an inverter 103, an inverter controller 104, and a control power supply generation circuit 105. Further, a high-pressure switch 107, a thermal protector 108, and a compressor thermistor 109 are connected to the control board 9.The rectifier 101 processes the AC voltage Vac supplied from the AC power source 10 to convert the AC voltage Vac to a DC voltage. The smoothing capacitor 102 smoothes the DC voltage obtained by the conversion by the rectifier 101 to generate a DC voltage to be supplied to the inverter 103. The inverter 103 generates the three-phase voltages Vu, Vv, and Vw from the DC voltage generated by the smoothing capacitor 102 under the control performed by the inverter controller 104. The inverter 103 applies a desired voltage to the motor 8 of the compressor 1.The control power supply generation circuit 105 generates various control power supplies from the DC voltage obtained through the conversion by the rectifier 101. In the present embodiment, the control power supply generation circuit 105 generates control power supplies to be supplied to the inverter 103 and the inverter controller 104.The inverter controller 104 controls the operation of the entire heat pump apparatus 100. Specifically, the inverter controller 104 controls the circulation direction of the four-way valve 2, the opening degree of the expander 4, the speed of a not-illustrated fan for cooling the heat exchanger 5, and the like so that the heat pump apparatus 100 reaches a desired operation state. The inverter controller 104 also controls the inverter 103 so that the motor 8 of the compressor 1 operates at a desired speed.The high pressure switch 107 switches when the discharge pressure of the compressor 1 has reached a preset pressure or more. Specifically, when the pressure in the compressor 1 has reached a preset threshold value or more, the high-pressure switch 107 mechanically opens a power supply path from the control power supply generation circuit 105 to mechanically stop a compressing operation of the compressor 1. When the pressure in the compressor 1 has become lower than the preset threshold value, the high-pressure switch 107 connects the power supply path from the control power supply generation circuit 105 again to resume the compressing operation of the compressor 1. The high-pressure switch 107 is turned off, i.e., opened, when the discharge pressure of the compressor 1, i.e., the pipe pressure of a refrigerant circuit, has reached at an installation position of the high-pressure switch 107, for example, 30 kg / cm 2 or more. The high-pressure switch 107 is turned on from off, i.e., brought from the opened state to a closed state, when the discharge pressure of the compressor 1, i.e., the pipe pressure of the refrigerant circuit at the installation position of the high-pressure switch 107, has become less than 28.5 kg / cm 2 for example. Therefore, the high pressure switch 107 does not switch back until the discharge pressure of the compressor 1, i.e., the pipe pressure of the refrigerant circuit at the installation position of the high pressure switch 107, becomes less than 28.5 kg / cm 2. The high pressure switch 107 according to the present embodiment takes several seconds to switch back. Alternatively, the high-pressure switch 107 may be installed on a power supply line for the inverter controller 104 and the inverter 103 via a relay or the like.The thermal protector 108 switches when the casing temperature of the compressor 1 has reached a preset temperature or more. In particular, the thermal protection device 108 is mounted on a housing of the compressor 1. When the casing temperature of the compressor 1 has reached a preset threshold value or more, the thermal protector 108 mechanically opens the power supply path from the control power supply generation circuit 105 to mechanically stop the compressing operation of the compressor 1. When the casing temperature of the compressor 1 has become lower than the preset threshold value, the thermal protector 108 connects the power supply path from the control power supply generation circuit 105 again to resume the compressing operation of the compressor 1. The thermal protection device 108 is switched off, i.e. opened, when the housing temperature of the compressor 1 has reached 125° C. or more, for example. The heat protector 108 is turned on from off, i.e., brought from the opened state to a closed state, when the casing temperature of the compressor 1 has become lower than 90° C., for example. Therefore, the thermal protector 108 does not switch back until the casing temperature of the compressor 1 becomes lower than 90° C. The thermal protector 108 according to the present embodiment takes a few 10 minutes to turn back. The period required until the shift-back depends on the threshold value of the heat protector 108, the heat capacity of the compressor 1, an outside air temperature, and the like. Alternatively, the thermal protector 108 may be installed on the power supply line for the inverter controller 104 and the inverter 103 via a relay or the like. Preferably, the housing temperature of the compressor 1 does not exceed 150° C. Therefore, although it depends on the temperature difference between the casing of the compressor 1 and the heat protector 108, it is appropriate that the temperature at which the heat protector 108 is opened is set to 115 to 135° C. In the description below, the thermal protector 108 may be referred to as a thermal switch. Further, in the description below, the casing temperature of the compressor 1 may be simply referred to as the temperature of the compressor 1. Note that the thermal protector 108 may be mounted at any position of the housing of the compressor 1. The position at which the heat protector 108 is mounted may be selected in consideration of the structure of the compressor 1 and the situation in which the compressor 1 is to be protected. For example, in a case where protection is to be performed even when the motor 8 of the compressor 1 is locked, the thermal protector 108 is preferably mounted, for example, at a position of the housing of the compressor 1 in the vicinity of the motor 8 of the compressor 1.The compressor thermistor 109 is a compressor temperature detector which is mounted on the casing of the compressor 1 and detects the casing temperature of the compressor 1. Furthermore, the compressor thermistor 109 is connected to the inverter controller 104. The inverter controller 104 limits the operation of the compressor 1 based on a detection value from the compressor thermistor 109, thereby reducing or preventing an increase in the casing temperature of the compressor 1. Further, the inverter controller 104 also detects the outside air temperature, so that the amount of liquid refrigerant that jams in the compressor 1 can be estimated based on the temperature difference from the casing temperature of the compressor 1. Note that, because the compressor 1 in the refrigeration cycle has a largest heat capacity and its temperature rises with a delay after an increase in the outside air temperature, the compressor 1 in the refrigeration cycle has a lowest temperature. Therefore, the temperature relationship is as shown in FIG. 3. FIG. 3 is a graph showing an example of a temporal change in the casing temperature, the outside air temperature, and the refrigerant storage amount of the compressor 1 of the heat pump apparatus 100 according to the first embodiment. In FIG. 3, the horizontal axis represents time and the vertical axis represents temperature. The inverter controller 104 may determine whether or not there is a congestion of a refrigerant in the compressor 1 and control an overheated operation of the compressor 1 based on the detection value from the compressor thermistor 109, i.e., the relationship between the housing temperature of the compressor 1 and the outside air temperature.The high-pressure switch 107 and the thermal protector 108 are disposed on the power supply line for supplying the inverter 103 and the inverter controller 104 with power from the controller power supply generating circuit 105. As described above, although a determination is made based on different parameters which are the pressure and the temperature, the high-pressure switch 107 and the thermal protector 108 may perform a same protected operation to cut off energization of the inverter controller 104 and the inverter 103 to stop the compressor 1. In the present embodiment, therefore, the high-pressure switch 107 and the thermal protector 108 are connected in series via the line and thus use a common line. Thereby, the heat pump apparatus 100 can use a conventional specification for the control board 9, and can use a combination of the conventional specification of the control board 9 and at least one of the specification of the high-pressure switch 107 and the specification of the heat protector 108 selected depending on the application. The heat pump apparatus 100 may have a configuration that does not include the high-pressure switch 107, depending on its application.Further, the heat pump apparatus 100 can reduce or prevent an increase in board component area resulting from the addition of connectors to the control board 9. In addition, compared with a case where the high-pressure switch 107 and the thermal protector 108 are disposed on different pipes, the heat pump apparatus 100 can shorten the total pipe length and can reduce the cost and reduce or prevent malfunction due to the influence of noise.In the heat pump apparatus 100 having the above-described configuration, when the discharge pressure of the compressor 1 has reached a preset pressure such as 30 kg / cm 2, or more, the high-pressure switch 107 switches and power supply to the inverter controller 104 and the inverter 103 is interrupted. This enables the heat pump apparatus 100 to reliably stop the compressor 1 even in a case where the inverter controller 104 cannot operate normally due to an outlier or the like.In the heat pump apparatus 100 having the above-described configuration, when the casing temperature of the compressor 1 has reached a preset temperature such as 125 ° C. or more, the heat protector 108 switches and power supply to the inverter controller 104 and the investor 103 is interrupted. This enables the heat pump apparatus 100 to reliably stop the compressor 1 even in a case where the inverter controller 104 cannot operate normally due to an outlier or the like.While in the present embodiment, the heat pump apparatus 100 interrupts power supply to the inverter controller 104 and the inverter 103 to stop the compressor 1, the interruption is not limited thereto. The heat pump apparatus 100 may cut off power supply of either the inverter controller 104 or the inverter 103 to stop the compressor 1. In particular, the high pressure switch 107 and the thermal protection device 108 interrupt at least one of:a connection point between the control power supply generation circuit 105 that supplies control power to the inverter 103 and the inverter 103; anda connection point between the control power supply generation circuit 105 that supplies control power to the inverter controller 104 and the inverter controller 104.In the present embodiment, in order to stop the compressor 1 more reliably, the heat pump apparatus 100 interrupts power supply to the inverter controller 104 and the inverter 103 to stop the compressor 1.Furthermore, while the inverter controller 104 controls only the inverter 103 in the present embodiment, the inverter controller 104 may control an inverter for driving a blower motor, an active converter, and the like. In this case, the heat pump apparatus 100 can stop the inverter 103, the inverter for driving the blower motor, the active converter, and the like, which are controlled by the inverter controller 104, by cutting off power supply to the inverter controller 104. This configuration enables the creation of a system with higher reliability and quality.Next, a hardware configuration of the inverter controller 104 of the control board 9 included in the heat pump apparatus 100 will be described. FIG. 4 is a diagram showing an example of the hardware configuration for implementing the inverter controller 104 of the control board 9 included in the heat pump apparatus 100 according to the first embodiment. The inverter controller 104 of the control board 9 is implemented by a processor 201 and a memory 202.The processor 201 is a central processing unit (CPU; also referred to as a central processing device, a processing device, a computing device, a microprocessor, a microcomputer, a processor or a digital signal processor (DSP)), or a highly integrated system (LSI). Examples of the memory 202 may include nonvolatile or volatile semiconductor memories such as a random access memory (RAM), a read only memory (ROM), a flash memory, an EPROM (erasable programmable read only memory), and an EEPROM (registered trademark) (electrically erasable programmable read only memory). Alternatively, the memory 202 is not limited thereto, and may be a magnetic disk, an optical disk, a compact disk, a mini disk, or a digital versatile disk (DVD).Second Embodiment.In a second embodiment, a case where a part of control performed by the inverter controller 104 in the first embodiment is performed by another control will be described.FIG. 5 is a diagram showing a circuit configuration of the control board 9 included in the heat pump apparatus 100 according to the second embodiment. The control board 9 additionally includes a system controller 106, as compared with the control board 9 of the first embodiment shown in FIG. 2. In the present embodiment, the heat pump apparatus 100 has a configuration including the inverter controller 104 and the system controller 106, i.e., two controllers, so that control of some targets controlled by the inverter controller 104 is transferred to the system controller 106.The system controller 106 is a host controller that controls the operation of the entire heat pump apparatus 100. Specifically, the system controller 106 controls the circulation direction of the four-way valve 2, the opening degree of the expander 4, the speed of a not-shown fan for cooling the heat exchanger 5, and the like, so that the heat pump apparatus 100 reaches a desired operating state. The system controller 106 also outputs operation commands to the inverter controller 104 so that the motor 8 of the compressor 1 operates at a desired speed. The inverter controller 104 controls the motor 8 according to the operation commands from the system controller 106.In the second embodiment, the control power supply generation circuit 105 also generates a control power supply to be supplied to the system controller 106, and supplies control power to the inverter 103 and the inverter controller 104 through paths different from each other.Therefore, the heat pump apparatus 100 can power the system controller 106 even in a state in which power supply to the inverter controller 104 and the inverter 103 is cut off. Furthermore, the system controller 106 may recognize that the high-pressure switch 107 or the thermal protector 108 has switched.For example, in the heat pump apparatus 100, in the heat protector 108, the period from a power cut of the inverter controller 104 and the inverter 103 to the power restoration is normally several 10 minutes, whereas in the high-pressure switch 107, it is several seconds, which is a great difference. Therefore, the system controller 106 can determine who has switched by measuring the duration from a power interruption of the inverter controller 104 and the inverter 103 until the power restoration. The period from a power supply interruption to the power supply restoration is referred to as a power supply interruption period. Alternatively, the system controller 106 may determine that the thermal protector 108 has switched when a predetermined time has elapsed after an interruption, rather than making a power recovery decision.The method for detecting a disconnection of a power supply may be such that the system controller 106 may directly detect a voltage or detect a signal indicating a disconnection of a power supply via a photo coupler, a transistor, or the like.Alternatively, the system controller 106 may make a determination based on the casing temperature, pressure information, or the like of the compressor 1 upon occurrence of disconnection or recovery in addition to the duration, and the determination based on the combination enables more accurate determination on who has switched the high-pressure switch 107 and the thermal protector 108. Specifically, the system controller 106 determines who has switched from the high pressure switch 107 and the thermal protector 108 using the detection value from the compressor thermistor 109 and / or the energization cut period.FIG. 6 is a flowchart showing the operation of the system controller 106 included in the heat pump apparatus 100 according to the second embodiment. The system controller 106 determines whether or not the duration from interruption of a control power supply to its recovery is less than one minute (step S1). As described above, this is based on the characteristic that it normally takes about several 10 minutes to restore when the high-pressure switch 107 is switched, whereas it normally takes several seconds to restore when the thermal protection device 108 is switched. When the duration from suspension of a control power supply to its restoration is less than one minute (step S 1: YES), the system controller 106 determines whether or not the casing temperature of the compressor 1 upon restoration of the control power supply is less than 100° C. (step S 2). When the casing temperature of the compressor 1 upon restoration of the control power supply is less than 100° C. (step S 2: YES), the system controller 106 determines whether or not the casing temperature of the compressor 1 upon restoration of the control power supply is greater than 80° C. (step S 3).In step S 2 and step S 3, when the switch-back temperature for the thermal protector 108 is set to 90° C., when the temperature is different by ±10% C. or more, the system controller 106 determines that it is not the thermal protector 108 but the high-pressure switch 107 that has switched. Note that the switch-back temperature does not need to be set in consideration of differences in detected temperatures caused by the positions at which the thermal protector 108 and the compressor thermistor 109 are mounted, their characteristics, and the like. When the casing temperature of the compressor 1 is greater than 80° C. upon restoration of the control power supply (step S 3: YES), the system controller 106 determines that the thermal protector 108 has switched (step S 4). When the duration from suspension of a control power supply to its recovery is equal to or greater than one minute (step S 1: NO), the system controller 106 determines that the thermal protector 108 has switched (step S 4). When the casing temperature of the compressor 1 at restoration of the control power supply is equal to or higher than 100° C. (step S 2: NO) or when the casing temperature of the compressor 1 at restoration of the control power supply is equal to or lower than 80° C. (step S 3: NO), the system controller 106 determines that the high-pressure switch 107 has switched (step S 5).The system controller 106 may perform a three minute restart prevention mode through the actions described above. Thereby, even when the high pressure switch 107 has switched, the heat pump apparatus 100 can prevent activation in a state in which the pressure difference is large, and can reduce or prevent damage caused by pipe vibration or the like, thereby making it possible to form a system with high reliability.In the present embodiment, the heat pump apparatus 100 includes two separate controllers, which are the system controller 106 and the inverter controller 104. Therefore, the heat pump apparatus 100 can be implemented by a microcomputer, which involves low cost with low arithmetic processing performance and a small number of pins even in a complicated system.While in the present embodiment, the heat pump apparatus 100 includes two separate controllers, which are the system controller 106 and the inverter controller 104, this is an example, and three or more controllers may be included. In this case, the heat pump apparatus 100 can constitute a more reliable system by constituting a system in which the controllers are mutually monitored.Further, because the heat pump apparatus 100 can determine which of the high-pressure switch 107 and the heat protector 108 has switched, a system having high utility and maintainability can be achieved.Further, in the heat pump apparatus 100, temperature detection means is not limited to the compressor thermistor 109, and the casing temperature of the compressor 1 can be estimated based on output information of the inverter 103, an ambient temperature of the compressor 1, an outside air temperature, and the like.Furthermore, the inverter controller 104 and the system controller 106 may be mounted on different control boards. In this case, when the system controller 106 and the control power supply generation circuit 105 are installed on a single control board, it is easy to form paths for interrupting power supply to the inverter controller 104 and the inverter 103.Although the control power supply for the inverter controller 104 and the inverter 103 is a single power supply from the control power supply generation circuit 105, a voltage of a control power supply is often 3.3 V or 5 V in a case where the inverter 103 is an intelligent power module (IPM), for example. Therefore, the heat pump apparatus 100 can supply control power supplies to the inverter controller 104 and the inverter 103 from control power supply generation circuits different from each other. The control power supply generation circuit 105 may generate control power supplies for the inverter controller 104 and the inverter 103 from a single power supply, or a power-down circuit, not shown, may decrease the voltage of the control power supply of the inverter 103 and supply the resultant control power supply to the inverter controller 104. The power-down circuit, not shown, reduces the voltage of a control power supply of 15 V for the inverter 103 to generate a control power supply of 3.3 V or 5 V. In this case, it is relatively easy to simultaneously cut off the control power supplies of the inverter controller 104 and the inverter 103.Note that the hardware configuration of the system controller 106 of the control board 9 included in the heat pump apparatus 100 is also constituted by the processor 201 and the memory 202 in a manner similar to the inverter controller 104.Third Embodiment.In a third embodiment, a heat pump system including the heat pump apparatus 100 will be described. Examples of the heat pump system include, but are not limited to, an air conditioner, a heat pump water heater, a refrigerator, and a chiller.FIG. 7 is a diagram showing an example of a configuration of a heat pump system 150 including the heat pump apparatus 100 according to the third embodiment. FIG. 8 is a Mollier diagram of the state of a refrigerant in the heat pump apparatus 100 according to the third embodiment. In FIG. 8, the horizontal axis represents a specific enthalpy and the vertical axis represents a refrigerant pressure.The heat pump apparatus 100 of the present embodiment includes a main refrigerant circuit 58 in which a compressor 51, a heat exchanger 52, an expander 53, a receiver 54, an internal heat exchanger 55, an expander 56, and a heat exchanger 57 are connected by pipes in series, and through which a refrigerant circulates. The main refrigerant circuit 58 includes a four-way valve 59 on an output side of the compressor 51 which enables switching of the circulation direction of the refrigerant. Further, the main refrigerant circuit 58 includes a blower 60 in the vicinity of the heat exchanger 57. note that the compressor 51 shown in FIG. 7 corresponds to the compressor 1 described in the first and second embodiments and includes the motor 8 driven by the inverter 103 and the compressor 7. For convenience of description, the control board 9 and the like are not shown in the heat pump system 150 shown in FIG. 7. In the description below, the heat exchanger 52 may be referred to as a first heat exchanger, and the heat exchanger 57 may be referred to as a second heat exchanger.Further, the heat pump apparatus 100 also includes an injection circuit 62 which is connected between the header 54 and the internal heat exchanger 55 via pipes to an injection pipe of the compressor 51. The expander 61 and the internal heat exchanger 55 are connected in series to the injection circuit 62. A water circuit 63 through which water circulates is connected to the heat exchanger 52. A fluid-using apparatus 64 using water such as a water heater, a radiator, a radiator for floor heating, or the like is connected to the water circuit 63. The fluid-using device 64 included in the heat pump system 150 is a device that uses a fluid resulting from heat exchange performed by the heat exchanger 52.First, the operation of the heat pump apparatus 100 of the present embodiment during a heating operation will be described. During the heating operation, the four-way valve 59 is set in the direction of the solid lines. Note that the heating operation includes not only heating using an air conditioner, but also a hot water supply that heats water to generate hot water.Gas-phase refrigerant (item 1 in FIG. 8 ) having high temperature and pressure in the compressor 51 is discharged from the compressor 51, subjected to heat exchange through the heat exchanger 52 which is a condenser and serves as a radiator, and therefore liquefied (item 2 in FIG. 8 ). In this process, the water circulating through the water circuit 63 is heated by heat discharged from the refrigerant, and used for heating, warm water supply, and the like.The liquid-phase refrigerant resulting from the liquefaction in the heat exchanger 52 is reduced in pressure by the expander 53, and thus enters a gas-liquid two-phase state (point 3 in FIG. 8 ). The refrigerant having entered the gas-liquid two-phase state by the expander 53 is subjected to heat exchange with a refrigerant drawn into the compressor 51 at the receiver 54, and therefore cooled and liquefied (point 4 in FIG. 8 ). The liquid-phase refrigerant resulting from the liquefaction in the receiver 54 is divided into a flow through the main refrigerant circuit 58 and a flow through the injection circuit 62.The liquid phase refrigerant which is separated by the refrigerant gas.When the main refrigerant circuit 58 flows, the refrigerant is reduced in pressure by the expander 61, and heat-exchanged with the refrigerant that has turned into the gas-liquid two-phase state and flows through the injection circuit 62 at the internal heat exchanger 55, and is thus cooled (point 5 in FIG. 8 ). The liquid-phase refrigerant resulting from cooling in the internal heat exchanger 55 is reduced in pressure by the expander 56, and thus enters a gas-liquid two-phase state (point 6 in FIG. 8 ). The refrigerant that has turned into the gas-liquid two-phase state by the expander 56 is subjected to heat exchange with outside air at the heat exchanger 57 serving as an evaporator, and therefore heated (point 7 in FIG. 8 ). The refrigerant heated by the heat exchanger 57 is then further heated at the receiver 54 (point 8 in FIG. 8 ) and drawn into the compressor 51.Meanwhile, the refrigerant flowing through the injection circuit 62 is reduced in pressure by the expander 61 (point 9 in FIG. 8 ) and subjected to heat exchange at the internal heat exchanger 55 (point 10 in FIG. 8 ) as described above. The refrigerant in the gas-liquid two-phase state resulting from the heat exchange at the internal heat exchanger 55, i.e., injection refrigerant, flows into the compressor 51 through the injection pipe of the compressor 55, thereby maintaining the gas-liquid two-phase state.In the compressor 51, the refrigerant sucked from the main refrigerant circuit 58 (point 8 in FIG. 8 ) is compressed to an intermediate pressure and heated (point 11 in FIG. 8 ). The refrigerant that has been compressed to the medium pressure and heated (point 11 in FIG. 8 ) is merged with the injection refrigerant (point 10 in FIG. 8 ) and is therefore lowered in temperature (point 12 in FIG. 8 ). The temperature-lowered refrigerant (point 12 in FIG. 8 ) is then further compressed, and heated to a high temperature and a high pressure and discharged (point 1 in FIG. 8 ).Note that when the heat pump apparatus 100 does not perform the injection operation, the opening degree of the expansion device 61 is set to be fully closed. In other words, the opening degree of the expansion device 61 is larger than a predetermined opening degree when the heat pump apparatus 100 performs the injection operation, and when the heat pump apparatus 100 does not perform the injection operation, the opening degree of the expansion device 61 is set to be smaller than the predetermined opening degree. Therefore, the refrigerant does not flow into the injection pipe of the compressor 51.Note that the opening degree of the expander 61 is electronically controlled by a controller such as a microcomputer.Next, the operation of the heat pump apparatus 100 of the present embodiment during a cooling operation will be described. During the cooling operation, the four-way valve 59 is set in the direction of the broken lines. Note that the cooling operation includes not only cooling used by an air conditioner, but also dissipating heat from water to make cold water, refrigeration, and the like.Gas-phase refrigerant (item 1 in FIG. 8 ) having high temperature and pressure in the compressor 51 is discharged from the compressor 51, subjected to heat exchange by the heat exchanger 57 which is a condenser and serves as a radiator, and therefore liquefied (item 2 in FIG. 8 ). The liquid-phase refrigerant resulting from the liquefaction in the heat exchanger 57 is reduced in pressure by the expansion device 56 and thus enters a gas-liquid two-phase state (point 3 in FIG. 8 ). The refrigerant that has turned into the gas-liquid two-phase state by the expander 56 is subjected to heat exchange in the internal heat exchanger 55, and therefore cooled and liquefied (point 4 in FIG. 8 ). In the internal heat exchanger 55, heat exchange is performed between the refrigerant that has transitioned to the gas-liquid two-phase state by the expander 56 and the refrigerant that has transitioned to the gas-liquid two-phase state (point 9 in FIG. 8 ) obtained by reducing the liquid-phase refrigerant that results from the liquefaction in the internal heat exchanger 55 in pressure by the expander 61. The liquid-phase refrigerant (point 4 in FIG. 8 ) resulting from the heat exchange in the internal heat exchanger 55 is divided into a flow through the main refrigerant circuit 58 and a flow through the injection circuit 62.The liquid-phase refrigerant flowing through the main refrigerant circuit 58 is subjected to heat exchange with the refrigerant drawn into the compressor 51 at the receiver 54, and therefore is further cooled (point 5 in FIG. 8 ). The liquid-phase refrigerant resulting from the cooling in the accumulator 54 is reduced in pressure by the expander 53, and thus enters the gas-liquid two-phase state (point 6 in FIG. 8 ). The refrigerant that has turned into the gas-liquid two-phase state by the expander 53 is subjected to heat exchange at the heat exchanger 52 serving as an evaporator, and is therefore heated (point 7 in FIG. 8 ). In this process, the refrigerant absorbs heat to cool the water circulating through the water circuit 63 which is used for cooling, refrigeration, and the like. As described above, the heat pump apparatus 100 according to the present embodiment constitutes the heat pump system 150 together with the fluid using apparatus 64 using water, i.e., a fluid circulating through the water circuit 63. The heat pump system 150 may be used in an air conditioner, a heat pump water heater, a refrigerator, a chiller, and the like.The refrigerant heated by the heat exchanger 52 is then further heated at the accumulator 54 (point 8 in FIG. 8 ) and drawn into the compressor 51.Meanwhile, the refrigerant flowing through the injection circuit 62 is reduced in pressure by the expander 61 (point 9 in FIG. 8 ) and subjected to heat exchange at the internal heat exchanger 55 (point 10 in FIG. 8 ) as described above. The refrigerant (injection refrigerant) in the gas-liquid two-phase state resulting from the heat exchange in the internal heat exchanger 55 flows into the compressor 51 through the injection pipe, thereby maintaining the gas-liquid two-phase state. The compression operation in the compressor 51 is the same as that during the heating operation.Note that when the heat pump apparatus 100 does not perform the injection operation, the opening degree of the expander 61 is set to be fully closed so that the refrigerant does not flow into the injection pipe of the compressor 51, which is the same as the operation in the heating operation.Further, in the above description, the heat exchanger 52 is described as a plate heat exchanger type heat exchanger that provides heat exchange between the refrigerant and the water circulating through the water circuit 63. The heat exchanger 52 is not limited thereto, and may provide heat exchange between the refrigerant and air. Further, regarding the water circuit 63, instead of the circuit through which water circulates, a circuit through which another fluid circulates may be used.As described above, the heat pump apparatus 100 can be used for heat pump apparatuses including an inverter compressor such as an air conditioner, a heat pump water heater, a refrigerator, and a chiller.The configurations presented in the above embodiments are examples and may be combined with other known technologies or with each other, or may be partially omitted or modified without departing from the spirit.List of reference characters1, 51 Compressor; 2, 59 Four-way valve; 3, 5, 52, 57 Heat exchanger; 4, 53, 56, 61 Expander; 6 Refrigerant pipe; 7 Compressor; 8 Motor; 9 Control board; 54 Collector; 55 Internal heat exchanger; 58 Main refrigerant circuit; 60 Blower; 62 Injection circuit; 63 Water circuit; 64 Fluid-using apparatus; 100 Heat pump apparatus; 101 Rectifier; 102 Smoothing capacitor; 103 Inverter; 104 Inverter controller; 105 Control power supply generation circuit; 106 System controller; 107 High-pressure switch; 108 Heat protector; 109 Compressor thermistor; 150 Heat pump system.

Claims

A heat pump apparatus (100) comprising: a compressor (1) including a compressor (7) that compresses a refrigerant and a motor (8) that drives the compressor (7); an inverter (103) that applies a desired voltage to the motor (8); an inverter controller (104) that controls the inverter (103); a control power supply generation circuit (105) that supplies control power to the inverter (103) and the inverter controller (104); a high-pressure switch (107) that switches when an output pressure of the compressor (1) reaches a preset pressure or more; A thermal switch (108) that switches when a temperature of the compressor (1) reaches a preset temperature or more, wherein the high-pressure switch (107) and the thermal switch (108) are installed on a power supply line for supplying power to the inverter (103), are connected in series via a line, and are connected via a single connector to a control board (9) on which at least one of the inverter controller (104) and the control power supply generation circuit (105) is mounted, and wherein the high-pressure switch (107) is opened when the output pressure of the compressor (1) reaches the preset pressure or more, or the thermal switch (108) is opened when the temperature of the compressor (1) reaches the preset temperature or more to cut off power supply to the inverter (103).The heat pump apparatus according to claim 1, wherein the high-pressure switch (107) and the heat switch (108) interrupt at least one of a connection point between the control power supply generation circuit (105) that supplies control power to the inverter (103) and the inverter (103) and a connection point between the control power supply generation circuit (105) that supplies control power to the inverter controller (104) and the inverter controller (104).The heat pump apparatus according to claim 1 or 2, comprising: a host controller (106) that outputs an operation command to the inverter controller (104).The heat pump apparatus according to claim 3, wherein the inverter controller (104) controls the motor (8) based on the operation command from the host controller (106).The heat pump apparatus according to claim 3 or 4, wherein the host controller (106) determines which of the high-pressure switch (107) and the heat switch (108) cuts off a power supply of the inverter (103).The heat pump apparatus according to claim 5, wherein the host controller (106) measures a power supply suspension period from a power supply suspension of the inverter (103) to a power supply restoration.The heat pumping apparatus according to claim 6, comprising: a compressor temperature detector (109) that detects the temperature of the compressor (1), wherein the host controller (106) determines who of the high pressure switch (107) and the heat switch (108) switches using at least one of a detection value from the compressor temperature detector (109) and the energization cut period.The heat pumping apparatus according to any one of claims 1 to 6, comprising a compressor temperature detector (109) that detects the temperature of the compressor (1).A heat pumping system (150) comprising: the heat pumping apparatus (100) according to any one of claims 1 to 8 having a refrigerant circuit (58) in which a compressor (51), a first heat exchanger (52), an expander (53; 56), and a second heat exchanger (57) are connected via pipes; and a fluid-using apparatus (64) that uses a fluid resulting from heat exchange performed by the first heat exchanger (52).An air conditioner comprising the heat pump apparatus (100) according to any one of claims 1 to 8.A refrigeration machine comprising the heat pump apparatus (100) according to any one of claims 1 to 8.

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