Control systems, heat pumps, control methods, control programs

Abstract

The system accurately detects the induced voltage of the motor corresponding to the temperature of the magnet. [Solution] The first sensor (41) is provided to detect the voltage applied to the electric motor (51). In the first process, the control unit (45) drives the stopped electric motor (51) under first conditions in which the value of the first temperature (T1), which changes in accordance with the driving of the compressor (21), and the value of the second temperature (T2) around the compressor (21) can be considered to be substantially the same as each other. Then, under second conditions in which the value of the first temperature (T1) can be considered to have not substantially changed from the value of the first temperature (T1) under first conditions, the control unit (45) drives the electric motor (51) to inertial rotation and inputs the output of the first sensor (41) during the inertial rotation of the electric motor (51) under second conditions.

Description

[Technical Field]

[0001] This disclosure relates to technology for controlling heat pump systems. [Background technology]

[0002] Patent Document 1 discloses a method for controlling the rotation of an electric motor by energizing it, then removing the energizer to allow it to rotate by inertia, and measuring the induced voltage during inertia. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-191769 [Overview of the project] [Problems that the invention aims to solve]

[0004] To accurately estimate the characteristics of the magnets installed in an electric motor, it is conceivable to accurately detect the induced voltage of the motor corresponding to the temperature of the magnets. However, Patent Document 1 does not disclose or suggest any such method. [Means for solving the problem]

[0005] A first aspect of the present disclosure relates to a control system for controlling a heat pump system (10) including a compressor (21) having an electric motor (51) having a magnet (53b) and a compression mechanism (55) driven by the electric motor (51), wherein the control system is: A first sensor (41) is provided to detect the voltage applied to the electric motor (51), A second sensor (42) is provided to detect a first temperature (T1), which is a temperature related to the compressor (21) and changes in accordance with the operation of the compressor (21), A third sensor (43) is provided to detect a second temperature (T2), which is the temperature around the compressor (21) and is different from the first temperature (T1), The system includes a control unit (45) that initiates the first process when a first start condition for initiating the first process is met, In the first process, the control unit (45) drives the stopped motor (51) under a first condition in which the value of the first temperature (T1) and the value of the second temperature (T2) can be considered to be substantially the same as each other, and then releases the drive of the motor (51) under a second condition in which the value of the first temperature (T1) can be considered to have not substantially changed from the value of the first temperature (T1) under the first condition, thereby allowing the motor (51) to rotate by inertia, and inputs the output of the first sensor (41) while the motor (51) is rotating by inertia under the second condition.

[0006] In the first embodiment, if the value of the first temperature (T1) and the value of the second temperature (T2) can be considered to be substantially the same, then the internal temperature of the compressor (21) is substantially uniform when the compressor (21) is stopped, and the "value of the first temperature (T1)", the "value of the second temperature (T2)", and the "value of the temperature of the magnet (53b) of the motor (51) provided in the compressor (21)" can be considered to be substantially the same. Therefore, the first and second conditions can be considered to be conditions under which the temperature of the magnet (53b) can be considered to be known. Accordingly, based on the output of the first sensor (41) input during the inertial rotation of the motor (51) under the second condition, the induced voltage of the motor (51) can be detected under conditions under which the temperature of the magnet (53b) can be considered to be known. This makes it possible to accurately detect the induced voltage of the motor (51) corresponding to the temperature of the magnet (53b).

[0007] A second aspect of this disclosure relates to the control system of the first aspect, The first temperature (T1) is the temperature of the discharge pipe (29) provided for discharging the fluid compressed by the compression mechanism (55) from the compressor (21). The second temperature (T2) is the temperature of the air surrounding the compressor (21). It is a control system.

[0008] In the second embodiment, the temperature of the discharge pipe (29) changes in accordance with the operation of the compressor (21). When the temperature value of the discharge pipe (29) and the temperature value of the air surrounding the compressor (21) can be considered to be substantially the same, the temperature inside the compressor (21) is substantially uniform when the compressor (21) is stopped, and the "temperature value of the discharge pipe (29)", the "temperature value of the air surrounding the compressor (21)", and the "temperature value of the magnet (53b) of the electric motor (51) provided in the compressor (21)" can be considered to be substantially the same.

[0009] A third aspect of this disclosure relates to a control system of the first or second aspect, The inertial rotation of the electric motor (51) in the first process is one rotation or more. It is a control system.

[0010] In the third embodiment, the induced voltage of the electric motor (51) can be accurately detected based on the output of the first sensor (41) which is input during the inertial rotation of the electric motor (51) for one or more revolutions.

[0011] A fourth aspect of this disclosure relates to a control system in any one of the first to third aspects, The first process is performed during a trial run conducted after the installation of the compressor (21). It is a control system.

[0012] In the fourth embodiment, the trial run is performed before normal operation. Therefore, the induced voltage corresponding to the temperature of the magnet (53b) of the electric motor (51) can be accurately detected before normal operation is performed.

[0013] A fifth aspect of this disclosure relates to a control system in any one of the first to fourth aspects, In the first process, the timing at which the driving of the motor (51) is released to cause coasting rotation of the motor (51) is the timing at which the load torque of the compressor (21) becomes lower than the average of the load torque in one cycle of the compressor (21). It is a control system.

[0014] In the fifth aspect, in a situation where the influence of the load torque of the compressor (21) (the influence on the coasting rotation of the motor (51)) is relatively small, the output of the first sensor (41) can be input during the coasting rotation of the motor (51). Thereby, the detection accuracy of the induced voltage of the motor (51) corresponding to the temperature of the magnet (53b) can be improved.

[0015] The sixth aspect of the present disclosure is in any one of the control systems of the first to fifth aspects, In the first process, the control unit (45) is based on any one of the first temperature (T1) under the first condition, the second temperature (T2) under the first condition, the first temperature (T1) under the second condition, and the second temperature (T2) under the second condition, and the amplitude and frequency of the induced voltage of the motor (51) detected during the coasting rotation of the motor (51) under the second condition. Estimate the relationship between the magnetic flux and temperature of the magnet (53b). It is a control system.

[0016] In the sixth aspect, the relationship between the magnetic flux of the magnet (53b) and the temperature of the magnet (53b) can be accurately estimated.

[0017] The seventh aspect of the present disclosure is in any one of the control systems of the first to sixth aspects, The control unit (45) performs the first process and the second process, After the first process is performed, when the second start condition for starting the second process is satisfied, the second process is performed, In the second process, the control unit (45) After driving the motor (51) which is stopped under the first condition, the motor (51) is allowed to rotate by inertia by releasing the drive to the motor (51) under the second condition. Based on the amplitude and frequency of the induced voltage of the motor (51) detected during the inertial rotation of the motor (51) under the second condition, and the amplitude and frequency of the induced voltage of the motor (51) detected during the inertial rotation of the motor (51) under the second condition in the first process, the degree of demagnetization of the magnet (53b) is estimated. It is a control system.

[0018] In the seventh embodiment, the degree of demagnetization of the magnet (53b) can be estimated with high accuracy.

[0019] An eighth aspect of this disclosure is a heat pump system comprising a control system of any one of the first to seventh aspects.

[0020] A ninth aspect of the present disclosure relates to a control method for controlling a heat pump system (10) including a compressor (21) having an electric motor (51) having a magnet (53b) and a compression mechanism (55) driven by the electric motor (51), wherein the control method is: A first step (ST21, ST22) is to drive the stopped motor (51) under a first condition in which the value of a first temperature (T1), which is a temperature related to the compressor (21) and a temperature that changes in accordance with the driving of the compressor (21), and the value of a second temperature (T2), which is the temperature around the compressor (21) and a temperature different from the first temperature (T1), can be considered to be substantially the same as each other, and then to release the drive of the motor (51) under a second condition in which the value of the motor (51) can be considered to have not substantially changed from the value of the first temperature (T1) under the first condition, thereby allowing the motor (51) to rotate by inertia, The system includes a second step (ST23) of detecting the voltage applied to the electric motor (51) during the inertial rotation of the electric motor (51) under the second condition.

[0021] In the ninth aspect, if the value of the first temperature (T1) and the value of the second temperature (T2) can be considered to be substantially the same, then the internal temperature of the compressor (21) is substantially uniform when the compressor (21) is stopped, and the "value of the first temperature (T1)", the "value of the second temperature (T2)", and the "value of the temperature of the magnet (53b) of the motor (51) provided in the compressor (21)" can be considered to be substantially the same. Therefore, the first and second conditions can be considered to be conditions under which the temperature of the magnet (53b) can be considered to be known. Accordingly, based on the output of the first sensor (41) input during the inertial rotation of the motor (51) under the second condition, the induced voltage of the motor (51) can be detected under conditions under which the temperature of the magnet (53b) can be considered to be known. This makes it possible to accurately detect the induced voltage of the motor (51) corresponding to the temperature of the magnet (53b).

[0022] The tenth aspect is a control program that causes a computer to execute the control method of the ninth aspect. [Brief explanation of the drawing]

[0023] [Figure 1] Figure 1 is a schematic diagram illustrating the configuration of a heat pump system according to an embodiment. [Figure 2] Figure 2 is a longitudinal cross-sectional view illustrating the configuration of a compressor. [Figure 3] Figure 3 is a graph illustrating the relationship between magnetic flux and magnetic temperature as shown in the magnetic properties map. [Figure 4] Figure 4 is a flowchart illustrating the flow of processing, including the first process. [Figure 5] Figure 5 is a graph illustrating the correction of the magnetic property map in the first processing step. [Figure 6] Figure 6 is a timing chart illustrating the changes in various parameters during the first process. [Figure 7] Figure 7 is a flowchart illustrating the flow of processing including the second process. [Figure 8]Figure 8 is a flowchart illustrating the flow of the operation restriction process. [Figure 9] Figure 9 is a flowchart illustrating the flow of the model correction process. [Figure 10] Figure 10 is a timing chart illustrating the changes in various parameters during the model correction process. [Modes for carrying out the invention]

[0024] The embodiments will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated. Furthermore, this disclosure is not limited to the embodiments shown below, and various modifications are possible without departing from the technical idea of ​​this disclosure. Since the drawings are for conceptual explanation of this disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for ease of understanding.

[0025] (Heat pump system) Figure 1 illustrates the configuration of a heat pump system (10) according to an embodiment. The heat pump system (10) comprises a refrigerant circuit (20) and a control system (30). In this example, the heat pump system (10) comprises an outdoor unit (11) installed outdoors and an indoor unit (12) installed indoors. The outdoor unit (11) functions as a heat source unit, and the indoor unit (12) functions as a utilization unit. The refrigerant circuit (20) is formed by connecting the outdoor unit (11) and the indoor unit (12) with refrigerant pipes.

[0026] In this example, the heat pump system (10) is an air conditioning system that provides air conditioning for the room. This heat pump system (10) is capable of selectively performing cooling and heating operations.

[0027] [Refrigerant circuit] The refrigerant circuit (20) performs a refrigeration cycle by circulating the refrigerant filled in the refrigerant circuit (20). In this example, the refrigerant circuit (20) includes a compressor (21), a four-way switching valve (22), a heat source heat exchanger (23), an expansion valve (24), and a utilization heat exchanger (25). Near the heat source heat exchanger (23), a heat source fan (26) is provided to transport the heat source air (outdoor air in this example) so that it passes through the heat source heat exchanger (23). Near the utilization heat exchanger (25), a utilization fan (27) is provided to transport the utilization air (indoor air in this example) so that it passes through the utilization heat exchanger (25).

[0028] The compressor (21), four-way switching valve (22), heat source heat exchanger (23), and heat source fan (26) are installed inside the casing (not shown) of the outdoor unit (11). The expansion valve (24), utilization heat exchanger (25), and utilization fan (27) are installed inside the casing (not shown) of the indoor unit (12).

[0029] The compressor (21) draws in refrigerant, compresses the drawn-in refrigerant, and discharges the compressed refrigerant. In this example, the compressor (21) is connected to an intake pipe (28) and a discharge pipe (29). The compressor (21) draws in refrigerant from the intake pipe (28) and discharges the refrigerant through the discharge pipe (29). Refrigerant is an example of a fluid that is compressed by the compressor (21). The configuration of the compressor (21) will be explained in detail later.

[0030] The four-way switching valve (22) has a first port (P1), a second port (P2), a third port (P3), and a fourth port (P4). The four-way switching valve (22) is switchable between a first state in which the first port (P1) and the fourth port (P4) are in communication and the second port (P2) and the third port (P3) are in communication, and a second state in which the first port (P1) and the third port (P3) are in communication and the second port (P2) and the fourth port (P4) are in communication.

[0031] In this example, the first port (P1) is connected to the discharge pipe (29). The second port (P2) is connected to the suction pipe (28). The third port (P3) is connected to the gas end of the utilization heat exchanger (25). The fourth port (P4) is connected to the gas end of the heat source heat exchanger (23).

[0032] The heat source heat exchanger (23) exchanges heat between the refrigerant flowing through the heat source heat exchanger (23) and the heat source air transported by the heat source fan (26). The heat source air that has undergone heat exchange in the heat source heat exchanger (23) is returned to the outside. For example, the heat source heat exchanger (23) is a fin-and-tube type heat exchanger. In this example, the liquid end of the heat source heat exchanger (23) is connected to the liquid end of the utilization heat exchanger (25) via an expansion valve (24).

[0033] The expansion valve (24) reduces the refrigerant pressure by expanding the refrigerant flowing through it. For example, the expansion valve (24) is an electrically operated valve with an adjustable opening. The expansion valve (24) is an example of a pressure reducing mechanism that reduces the refrigerant pressure.

[0034] The utilization heat exchanger (25) exchanges heat between the refrigerant flowing through the utilization heat exchanger (25) and the utilization air transported by the utilization fan (27). The utilization air that has undergone heat exchange in the utilization heat exchanger (25) is returned to the room. For example, the utilization heat exchanger (25) is a fin-and-tube type heat exchanger.

[0035] When cooling operation is performed in the heat pump system (10), the four-way switching valve (22) is set to the first state and the compressor (21) is driven. As a result, the heat source heat exchanger (23) becomes a heat radiator and the utilization heat exchanger (25) becomes an evaporator. In this way, the utilization air (indoor air) is cooled in the utilization heat exchanger (25) and the room is cooled.

[0036] When heating operation is performed in the heat pump system (10), the four-way switching valve (22) is set to the second state and the compressor (21) is driven. As a result, the utilization heat exchanger (25) becomes a heat radiator and the heat source heat exchanger (23) becomes an evaporator. In this way, the utilization air (indoor air) is heated in the utilization heat exchanger (25) and the room is heated.

[0037] Hereinafter, the term "refrigeration cycle operation" will be used to refer to both the cooling and heating operations performed by the refrigeration cycle of the refrigerant circuit (20), the refrigeration cycle operation performed experimentally after the installation of the compressor (21) will be referred to as "test run," and the normal refrigeration cycle operation performed after the test run will be referred to as "normal operation." The test run is performed before the normal operation. Test runs include test runs performed after the compressor (21) is installed in the outdoor unit (11) (test runs performed at the factory before shipment from the factory), and test runs performed after the installation of the heat pump system (10) (test runs performed at the installation site after shipment from the factory).

[0038] [Compressor configuration] Figure 2 illustrates the configuration of the compressor (21). In this example, the compressor (21) is a high-pressure dome-type compressor and comprises a casing (50), an electric motor (51), a compression mechanism (55), and a drive shaft (56).

[0039] The casing (50) houses the electric motor (51), the compression mechanism (55), and the drive shaft (56). In this example, the casing (50) is formed in a cylindrical shape that extends vertically and is closed at both ends. The casing (50) is connected to an intake pipe (28) and a discharge pipe (29). The intake pipe (28) passes through the body of the casing (50) and is connected to the compression mechanism (55). The discharge pipe (29) passes through the top of the casing (50) and communicates with the internal space of the casing (50).

[0040] The electric motor (51) has a stator (52) and a rotor (53). In this example, the electric motor (51) is an embedded magnet type electric motor. The stator (52) has a cylindrical stator core (52a) and a plurality of coils (52b). The plurality of coils (52b) are wound around a plurality of teeth (not shown) formed on the stator core (52a). The rotor (53) is positioned radially inside the stator (52) and faces the stator (52) radially across a predetermined air gap. The rotor (53) has a cylindrical rotor core (53a) and a plurality of magnets (53b). The plurality of magnets (53b) are permanent magnets and are inserted into a plurality of slots (not shown) formed on the rotor core (53a).

[0041] The compression mechanism (55) compresses the refrigerant. In this example, the compression mechanism (55) is located below the electric motor (51). The compression mechanism (55) compresses the refrigerant drawn in through the suction pipe (28) and discharges the compressed refrigerant into the internal space of the casing (50). The fluid discharged into the internal space of the casing (50) is discharged through the discharge pipe (29). In this example, the compression mechanism (55) is a rotary compression mechanism.

[0042] The drive shaft (56) connects the electric motor (51) and the compression mechanism (55). The rotor (53) of the electric motor (51) is fixed to the drive shaft (56). In this example, the drive shaft (56) extends in the vertical direction. The electric motor (51) rotates the drive shaft (56). The rotational drive of the drive shaft (56) drives the compression mechanism (55).

[0043] [Control System] The control system (30) controls the heat pump system (10). As shown in Figure 1, in this example, the control system (30) includes a power converter (35), various sensors (40), a memory unit (44), and a control unit (45).

[0044] [Power converter] The power converter (35) converts the power supply voltage supplied from the power source (5) into an output AC voltage having a predetermined frequency and amplitude, and drives the motor (51) included in the compressor (21) by supplying the output AC voltage to the motor (51). In this example, the power converter (35) has a converter (36), a DC section (37), and an inverter (38). In this example, the power source (5) is a single-phase AC power source, and the output AC voltage is a three-phase AC voltage.

[0045] The converter (36) rectifies the power supply voltage supplied from the power supply (5). In this example, the converter (36) full-wave rectifies the AC power supply voltage supplied from the power supply (5). For example, the converter (36) is composed of a diode bridge circuit in which multiple rectifier diodes are connected in a bridge configuration.

[0046] The DC section (37) generates a DC voltage corresponding to the power supply voltage supplied from the power supply (5). In this example, the DC section (37) has a capacitor and generates the DC voltage by smoothing the output of the converter (36).

[0047] The inverter (38) has multiple switching elements, and the switching operation of the multiple switching elements converts the output of the DC section (37) into an output AC voltage having a predetermined frequency and amplitude. The inverter (38) is an example of a conversion unit that converts the DC voltage generated by the DC section (37) into an AC voltage by switching operation.

[0048] For example, the inverter (38) has six bridge-connected switching elements and six freewheeling diodes connected in antiparallel to each of the six switching elements. More specifically, the inverter (38) has three switching legs, each consisting of two switching elements connected in series. The midpoints of the three switching legs (specifically, the connection points between the switching elements on the upper arm and the switching elements on the lower arm) are connected to three types of coils (U-phase, V-phase, and W-phase coils) of the motor (51), respectively.

[0049] [Various sensors] Various sensors (40) are provided to detect various physical quantities in the heat pump system (10). Various information (detected values) detected by the various sensors (40) is transmitted to the control unit (45). The various sensors (40) include a first sensor (41), a second sensor (42), and a third sensor (43).

[0050] The first sensor (41) is provided to detect the voltage applied to the motor (51). In this example, the first sensor (41) is a voltage sensor that detects the line voltage of the motor (51). The voltage applied to the motor (51) is the line voltage of the motor (51). This "voltage applied to the motor (51)" includes the induced voltage generated in the motor (51) in accordance with the rotation of the motor (51).

[0051] The second sensor (42) is provided to detect the first temperature (T1). The first temperature (T1) is a temperature related to the compressor (21) and is a temperature that changes in accordance with the operation of the compressor (21). In this example, the second sensor (42) is composed of a temperature sensor that detects the temperature of the discharge pipe (29) connected to the compressor (21). The first temperature (T1) is the temperature of the discharge pipe (29).

[0052] The third sensor (43) is provided to detect the second temperature (T2). The second temperature (T2) is the temperature around the compressor (21) and is different from the first temperature (T1). Specifically, the type of the second temperature (T2) is different from the type of the first temperature (T1), but the value of the second temperature (T2) can be the same as the value of the first temperature (T1). In this example, the third sensor (43) is a temperature sensor that detects the temperature of the heat source air (outdoor air) being transported to the heat source heat exchanger (23). The second temperature (T2) is the temperature of the heat source air being transported toward the heat source heat exchanger (23) by the heat source fan (26). The temperature of the heat source air being transported toward the heat source heat exchanger (23) is the temperature of the heat source air before it passes through the heat source heat exchanger (23), and is an example of the temperature of the air around the compressor (21). Note that the temperature around the compressor (21) is the temperature inside the casing that houses the compressor (21) (in this example, the casing of the outdoor unit (11)).

[0053] In the following explanation, for the sake of simplicity, the "value of the first temperature (T1)" will simply be referred to as "first temperature (T1)," and the "value of the second temperature (T2)" will simply be referred to as "second temperature (T2)."

[0054] The temperature inside the casing may include the temperature detected by a sensor located outside the casing (e.g., the temperature of the air). The temperature detected by the sensor may be considered to be substantially the same as the temperature inside the casing. The temperature around the compressor (21) may include the temperature detected by the sensor.

[0055] In this example, the various sensors (40) include sensors provided to detect physical quantities used to control the operation of the refrigeration cycle (specifically, physical quantities used in the operation control processing described later). Examples of such physical quantities include the rotational speed and rotational angle of the electric motor (51), the DC voltage in the DC section (37), the voltage applied to the electric motor (51), the current flowing through the electric motor (51), the pressure and temperature of the refrigerant (low-pressure refrigerant in the refrigerant circuit (20)) drawn into the compressor (21), the pressure and temperature of the refrigerant (high-pressure refrigerant in the refrigerant circuit (20)) discharged from the compressor (21), the temperature of the heat source air transported toward the heat source heat exchanger (23), and the temperature of the utilization air transported toward the utilization heat exchanger (25). Sensors provided to detect these physical quantities may be used in conjunction with any one of the first sensor (41), second sensor (42), and third sensor (43) described above.

[0056] In this example, the various sensors (40) include sensors provided to detect "physical quantities related to the compressor (21)" which are input to the estimation model described later. In this example, the physical quantities related to the compressor (21) include the rotational speed of the electric motor (51) and the temperature of the discharge pipe (29). The sensors provided to detect these "physical quantities related to the compressor (21)" may be used as one of the first sensor (41), second sensor (42), and third sensor (43) described above, or they may be used as one of the sensors used to detect physical quantities used to control the operation of the refrigeration cycle.

[0057] The various sensors (40) described above may be sensors provided to directly detect the physical quantities described above, or sensors provided to indirectly detect or estimate the physical quantities described above.

[0058] [Storage section] The memory unit (44) stores various information and data. In this example, the memory unit (44) stores information and data used for controlling the heat pump system (10) (e.g., setting values ​​such as thresholds, data structures such as characteristic maps and calculation models), information obtained by various sensors (40) installed in the heat pump system (10) (e.g., measured values), and information obtained by the control unit (45) (e.g., calculation results). In this example, the memory unit (44) also stores a magnet characteristic map and an estimation model.

[0059] [Magnetic Properties Map] The magnet characteristic map shows the relationship between the "magnetic flux" of the magnet (53b) contained in the electric motor (51) and the "magnetic temperature" of the magnet (53b). As shown in Figure 3, the magnet characteristic map displays a characteristic curve (L) that shows the relationship between the magnetic flux and the magnetic temperature.

[0060] The characteristic curve (L) may be represented by a lookup table that associates magnetic flux with magnetic temperature, or by a formula that allows the magnetic temperature to be derived by substituting the magnetic flux.

[0061] As the temperature of the magnet (53b) increases, the residual magnetic flux density of the magnet (53b) decreases, resulting in a decrease in the magnetic flux of the magnet (53b). The magnet (53b) has this characteristic. The characteristic curve (L) showing the relationship between the magnetic flux of the magnet and the temperature of the magnet is determined by the material that makes up the magnet (53b).

[0062] Furthermore, variations in the manufacturing of the magnets (53b) and changes in the internal state of the compressor (21) (manufacturing variations and deterioration) can alter the relationship between the magnet flux and the magnet temperature. Therefore, it is important to correct (calibrate) the magnet characteristic map for each compressor (21).

[0063] Also, if the magnet temperature and the magnetic flux of the magnet at that magnet temperature can be found, the relationship between the magnet temperature and the magnetic flux (specifically, the characteristic curve (L)) can be uniquely determined. Therefore, by accurately estimating the magnetic flux corresponding to the magnet temperature, it becomes possible to accurately estimate the relationship between the magnet temperature and the magnetic flux.

[0064] 〔Estimation Model〕 The estimation model is generated to estimate the temperature of the magnet (53b) based on the physical quantities related to the compressor (21). In this example, the above-mentioned "physical quantities related to the compressor (21)" include the rotational speed of the electric motor (51) and the temperature of the discharge pipe (29).

[0065] Also, in this example, the estimation model is a regression equation (multiple regression equation) generated using "multiple regression analysis", which is a type of regression analysis method. Specifically, the estimation model uses the "rotational speed of the electric motor (51)" and the "temperature of the discharge pipe (29)" as explanatory variables, and the "temperature of the magnet (53b)" as the objective variable, and performs multiple regression analysis on the explanatory variables and the objective variable to generate a regression equation (multiple regression equation). The data (explanatory variables and objective variable) used in the multiple regression analysis can be obtained from the results of tests using an actual machine (the actually installed heat pump system (10)), the results of simulations performed on a computer, etc.

[0066] The regression equation that is the estimation model is represented by the following equation. In the following equation, "T m " represents the magnet temperature (Tm), "R" represents the rotational speed of the electric motor (51), "T t " represents the temperature of the discharge pipe (29), and "K n (n is an integer)" represents a coefficient.

[0067] T m =K1×T t +K2×(R-K3)×(T t -K4)+K5×(R-K6) 2 +K7×(T t -K8) 2 +K9

[0068] The estimation model may be a pre-trained model generated using AI (Artificial Intelligence). Specifically, the estimation model may be a pre-trained model that uses "the rotational speed of the electric motor (51)" and "the temperature of the discharge pipe (29)" as explanatory variables and "the temperature of the magnet (53b)" as the dependent variable, and is machine-trained based on known data of the explanatory and dependent variables. The above known data (explanatory and dependent variables) can be obtained from the results of tests using an actual machine (an actually installed heat pump system (10)), the results of simulations performed on a computer, etc. An example of machine learning is deep learning.

[0069] The pre-trained model, which is an estimation model, takes "the rotational speed of the electric motor (51)" and "the temperature of the discharge pipe (29)" as input data and outputs "the temperature of the magnet (53b)" as output data.

[0070] [Control Unit] The control unit (45) receives (acquires) information and data from various parts of the heat pump system (10). The control unit (45) also receives various instructions. Examples of instructions received by the control unit (45) include an operation start instruction to start the refrigeration cycle operation and an operation stop instruction to end the refrigeration cycle operation. These various instructions may be transmitted to the control unit (45) from an operation unit (not shown) provided in the heat pump system (10). The operation unit transmits various instructions to the control unit (45) in response to operations entered by the operator. For example, the operation unit is a remote controller having operators such as operation buttons.

[0071] The control unit (45) then performs various processes by controlling each part of the heat pump system (10) based on information and data input from each part of the heat pump system (10) and instructions input to the control unit (45).

[0072] For example, the control unit (45) is composed of a computer (microcomputer) including a processor, memory, input / output interfaces, etc. The memory is electrically connected to the processor and stores programs and data for operating the processor. The various processes (functions) of the control unit (45) are realized when the program is executed by the processor. The control unit (45) also includes control components (e.g., electrical circuits and electronic circuits).

[0073] In this example, the control unit (45) performs operation control processing, first processing, second processing, operation limiting processing, and model correction processing. The processing performed by the control unit (45) is an example of a control method. The control unit (45) (processor) is an example of a computer that executes the control method. The program stored in the memory of the control unit (45) is an example of a control program that causes the computer to execute the above control method.

[0074] [Operation control processing] The operation control process is a process for controlling the refrigeration cycle operation performed in the heat pump system (10). The operation control process is performed during normal operation and trial operation. In the operation control process, the control unit (45) controls each part of the heat pump system (10) so that the desired refrigeration cycle operation is performed.

[0075] In this example, the control unit (45) controls the voltage supplied from the power converter (35) to the motor (51) by controlling the switching operation of the inverter (38) of the power converter (35) during the operation control process. This controls the current flowing to the motor (51) and the rotational speed of the motor (51). As a result, the pressure of the refrigerant discharged from the compressor (21) is controlled. The control unit (45) also controls the opening degree of the expansion valve (24), the starting and stopping of the heat source fan (26), the starting and stopping of the utilization fan (27), and the switching of the four-way switching valve (22) during the operation control process. These controls are well known controls related to refrigeration cycle operation.

[0076] [First process] The first process is to input the output of the first sensor (41) while the motor (51) is inertially rotating under predetermined conditions that allow the temperature of the magnet (53b) to be estimated. In this example, the first process is a process (calibration process) to correct the magnet characteristic map using the output of the first sensor (41). The first process is performed during trial operation (specifically at the start of trial operation).

[0077] Next, with reference to Figure 4, the processing flow including the first process will be explained. In this example, the control unit (45) performs the processing shown in Figure 4 when the condition that the setting (calibration) of the magnet characteristic map is not yet complete is met.

[0078] For example, when the control unit (45) has finished setting the magnet characteristic map, it sets a setting completion flag. Setting the flag is equivalent to changing the value of a variable stored in the memory unit (44). The control unit (45) determines whether or not the setting of the magnet characteristic map has been completed by referring to the setting completion flag.

[0079] Note that the following steps (ST21~ST26) are examples of the first process. Steps (ST21, ST22) are examples of the first step, and step (ST23) is an example of the second step.

[0080] <Step (ST11)> The control unit (45) determines whether or not an operation start instruction has been input. If an operation start instruction has been input, the process in step (ST12) is performed.

[0081] <Step (ST12)> When an operation start instruction is input, the control unit (45) determines whether the operation stop time is equal to or greater than a predetermined time. If the operation stop time is equal to or greater than a predetermined time, the process in step (ST13) is performed; otherwise, the process in step (ST15) is performed.

[0082] The shutdown time is the time from the time the refrigeration cycle was last stopped until the present time. When the control unit (45) stops the refrigeration cycle, it starts measuring the shutdown time. The predetermined time is set to a time when sufficient time has elapsed since the last refrigeration cycle was last stopped, so that the pressure inside the heat pump system (10) has stabilized (equalized pressure), and the temperatures related to the compressor (21) (specifically, the first temperature (T1), the second temperature (T2), and the temperature of the magnet (53b)) can be considered to be substantially the same.

[0083] Furthermore, if the refrigeration cycle has not been operated up to this point, the shutdown time is set to a time longer than the predetermined time in step (S12) (the time that serves as the threshold for deciding whether or not to perform the processing in step (ST13)). In other words, the initial value of the shutdown time is set to a time longer than the predetermined time mentioned above, and thereafter, each time the refrigeration cycle is stopped, the shutdown time is reset to zero and measurement of the shutdown time begins. With this setting and control, even if the refrigeration cycle has not been operated up to this point, the processing from step (S13) onward can be performed.

[0084] <Step (S13)> The control unit (45) detects a first temperature (T1) based on the output of the second sensor (42) and detects a second temperature (T2) based on the output of the third sensor (43). The control unit (45) then determines whether the first temperature (T1) and the second temperature (T2) can be considered to be substantially the same. If the first temperature (T1) and the second temperature (T2) can be considered to be substantially the same, the process of step (ST21) is performed; otherwise, the process of step (ST15) is performed.

[0085] Furthermore, the state in which "the first temperature (T1) and the second temperature (T2) can be considered to be substantially the same" means, for example, that "the difference between the first temperature (T1) and the second temperature (T2) is less than or equal to a predetermined error (for example, 1°C or less)."

[0086] <Step (ST15)> If an operation start instruction is received but the operation stop time is not longer than a predetermined time, or if an operation start instruction is received but the first temperature (T1) and the second temperature (T2) cannot be considered to be substantially the same, the control unit (45) starts the operation control process without performing the first process.

[0087] <Step (ST21)> In this example, the first start condition is met when all of the following conditions are met: the magnet characteristic map has not been set up (the start condition for the process shown in Figure 4), an operation start instruction is entered (YES in step (ST11)), the operation stop time is longer than a predetermined time (YES in step (ST12)), and the first temperature (T1) and the second temperature (T2) are substantially the same (YES in step (ST13)). The first start condition is the condition for starting the first process.

[0088] When the first start condition is met, the control unit (45) drives the stopped motor (51) under the first condition in which the first temperature (T1) and the second temperature (T2) can be considered to be substantially the same. Specifically, the control unit (45) drives the stopped motor (51) by controlling the inverter (38) of the power converter (35) so that voltage is supplied from the power converter (35) to the motor (51).

[0089] In this example, if the first start condition is met, the first condition is also met. The processing of step (ST21) may start simultaneously with the meeting of the first start condition, or it may start during the period from when the first start condition is met until when the first condition is no longer met (the period during which the first condition is met). Alternatively, the control unit (45) may determine whether the first condition is met after the first start condition is met, and the processing of step (ST21) may start after it is determined that the first condition is met.

[0090] <Step (ST22)> Next, the control unit (45) allows the motor (51) to rotate by inertia by releasing the drive of the motor (51) under the second condition in which the first temperature (T1) can be considered to have not changed substantially from the first temperature (T1) under the first condition. Specifically, the control unit (45) releases the drive of the motor (51) by controlling the inverter (38) of the power converter (35) so that the supply of voltage from the power converter (35) to the motor (51) is stopped.

[0091] Furthermore, the state in which "the first temperature (T1) can be considered to have not substantially changed from the first temperature (T1) under the first conditions" means, for example, that "the difference between the first temperature (T1) at the present time and the first temperature (T1) under the first conditions is less than or equal to a predetermined error (for example, 1°C or less)."

[0092] In this example, the control unit (45) also deactivates the motor (51) during the low-torque period when the load torque of the compressor (21) is lower than the average load torque of the compressor (21) over one cycle. In other words, the point at which the motor (51) is deactivated in order to allow the motor (51) to rotate by inertia in the first process is when the load torque of the compressor (21) is lower than the average load torque of the compressor (21) over one cycle.

[0093] The "average load torque" mentioned above may be a value measured during the operation of the compressor (21), or a value estimated based on the operating conditions of the compressor (21). For example, the "average load torque" mentioned above may be the average load torque of the compressor (21) over one cycle obtained when the motor (51) is rotated at the same rotational speed as the motor (51) at the start of its inertial rotation for one or more rotations.

[0094] Furthermore, the load torque of the compressor (21) changes in accordance with the change in the rotation angle (electrical angle) of the electric motor (51). Therefore, the period of low torque can be estimated based on the rotation angle of the electric motor (51). For example, the control unit (45) determines whether the current time falls within the low torque period based on the rotation angle of the electric motor (51).

[0095] In this example, the inertial rotation of the electric motor (51) in the first process is one rotation or more. In the first process, the control unit (45) releases the drive of the electric motor (51) so that the rotational speed of the electric motor (51) when the drive of the electric motor (51) is released is "a rotational speed that allows the electric motor (51) to rotate one rotation or more by inertial rotation".

[0096] In this example, the driving time and rotational speed of the motor (51) in the first process are set to a time and rotational speed that substantially maintain the first temperature (T1) from the first temperature (T1) under the first conditions. The control unit (45) drives the motor (51) in the first process so that the first temperature (T1) does not substantially change from the first temperature (T1) under the first conditions. For example, the time and rotational speed that substantially maintain the first temperature (T1) from the first temperature (T1) under the first conditions are a few seconds and 16 rps.

[0097] <Step (ST23)> Next, the control unit (45) inputs the output of the first sensor (41) while the motor (51) is inertially rotating under the second condition. Specifically, the control unit (45) continues to input the output of the first sensor (41) in such a way that it obtains the "output of the first sensor (41) within a predetermined time" necessary to detect the induced voltage of the motor (51). The time for which the output of the first sensor (41) is input is at least the predetermined time.

[0098] <Step (ST24)> Next, the control unit (45) detects the induced voltage of the motor (51) based on the output of the first sensor (41) input during the inertial rotation of the motor (51) under the second condition. In this example, the control unit (45) detects the "line voltage of the motor (51)" obtained by the voltage sensor, which is the first sensor (41), as the induced voltage of the motor (51).

[0099] <Step (ST25)> Next, the control unit (45) estimates the magnetic flux (Aa), which is the magnetic flux of the magnet (53b) included in the motor (51), based on the amplitude and frequency of the induced voltage of the motor (51) detected in step (ST24). In this example, the control unit (45) estimates the magnetic flux (Aa) by substituting the above-mentioned amplitude and frequency of the induced voltage into the following calculation formula. In the following calculation formula, “A a " indicates the magnetic flux (Aa), and "V a " indicates the amplitude of the induced voltage, and "f a " indicates the frequency of the induced voltage.

[0100] A a =V a / (√2(2π×f a ))

[0101] Furthermore, the control unit (45) estimates the magnet temperature (Tm), which is the temperature of the magnet (53b) included in the electric motor (51), based on one of the following: "first temperature (T1) under first conditions", "second temperature (T2) under first conditions", "first temperature (T1) under second conditions", and "second temperature (T2) under second conditions". In this example, the control unit (45) estimates one of the above four temperatures as the "magnet temperature (Tm)".

[0102] The control unit (45) then estimates the relationship between the magnetic flux (Aa) and the magnetic temperature (Tm) based on the magnetic flux (Aa) and the magnetic temperature (Tm).

[0103] Specifically, as shown in Figure 5, the control unit (45) determines a characteristic curve (L) that shows the relationship between magnetic flux (Aa) and magnetic temperature (Tm) in a planar coordinate system (graph) where the flux axis showing magnetic flux (Aa) and the temperature axis showing magnetic temperature (Tm) are orthogonal, such that the estimated point (Q) plotted based on the estimated magnetic flux (Aa) and magnetic temperature (Tm) is placed on the characteristic curve (L). For example, the control unit (45) selects a magnetic characteristic map from among several pre-prepared magnetic characteristic maps that allows the estimated point (Q) to be placed on the characteristic curve (L) (or a magnetic characteristic map that represents the characteristic curve (L) that is closest to the estimated point (Q)).

[0104] <Step (ST26)> Next, the control unit (45) corrects the magnet characteristic map stored in the memory unit (44) based on the estimated relationship between the magnet flux (Aa) and the magnet temperature (Tm) in step (ST25).

[0105] As shown in Figure 5, if the characteristic curve (L) (shown as a dashed line) represented in the magnet characteristic map (hereinafter referred to as the "default magnet characteristic map"), which is actually used in various processes such as the model correction process described later, deviates from the characteristic curve (L) (shown as a solid line) estimated in step (ST25), the control unit (45) corrects the default magnet characteristic map so that the characteristic curve (L) represented in the default magnet characteristic map becomes the characteristic curve (L) estimated in step (ST25). For example, the control unit (45) sets the magnet characteristic map selected in step (ST25) from among a plurality of pre-prepared magnet characteristic maps as the "default magnet characteristic map".

[0106] <Step (ST27)> Next, the control unit (45) completes the first process and starts the operation control process.

[0107] [Specific example of the first process] Next, with reference to Figure 6, the changes in various parameters in the process including the first process will be explained in detail. Figure 6 illustrates various parameters, including the rotational speed of the electric motor (51), the induced voltage of the electric motor (51), and the temperatures related to the compressor (21) (first temperature (T1), second temperature (T2), and magnet temperature (Tm)).

[0108] At time (t1), the control unit (45) controls the power converter (35) so that the voltage supply from the power converter (35) to the motor (51) is stopped. As a result, the drive of the motor (51) is released and the motor (51) begins to rotate by inertia. The rotational speed of the motor (51) gradually decreases from the rotational speed (R0) in the operation control process, becomes zero at time (t2), and the motor (51) stops.

[0109] When the electric motor (51) stops, the compressor (21) also stops. As a result, the pressure within the heat pump system (10) approaches a stable state (equal pressure state), and the temperatures associated with the compressor (21) (specifically, the first temperature (T1), the second temperature (T2), and the magnet temperature (Tm)) approach substantially the same temperature. Finally, the first temperature (T1), the second temperature (T2), and the magnet temperature (Tm) can be considered to be substantially the same.

[0110] At time (t3), an operation start instruction is input to the control unit (45). In this example, the operation stop time (specifically, the length of time from time (t1) to time (t3)) is greater than or equal to a predetermined time. Also, at time (t3), the first temperature (T1) and the second temperature (T2) can be considered to be substantially the same. As a result, the first start condition is met, and the first process begins.

[0111] Furthermore, time (t3) is the time under the first condition in which the first temperature (T1) and the second temperature (T2) can be considered to be substantially the same. When the first process starts at time (t3), the control unit (45) controls the power converter (35) so that it starts supplying voltage from the power converter (35) to the motor (51). As a result, the motor (51) starts to drive under the first condition. The rotational speed of the motor (51) gradually increases and reaches the first rotational speed (R1) at time (t4).

[0112] Time (t4) is the time under the second condition in which the first temperature (T1) can be considered to have not substantially changed from the first temperature (T1) under the first condition (the first temperature (T1) at time (t3) in the example of Figure 6). Then, at time (t4), the control unit (45) controls the power converter (35) so that the supply of voltage from the power converter (35) to the motor (51) is stopped. As a result, the drive of the motor (51) is released under the second condition, and the motor (51) begins to rotate by inertia. The rotational speed of the motor (51) gradually decreases from the first rotational speed (R1), becomes zero at time (t5), and the motor (51) stops.

[0113] The period from time (t4) to time (t5) is a period under second conditions in which the first temperature (T1) can be considered to have not substantially changed from the first temperature (T1) under first conditions (in the example of Figure 6, the first temperature (T1) at time (t3)). During the period from time (t4) to time (t5), the control unit (45) receives the output of the first sensor (41). This allows the control unit (45) to receive the output of the first sensor (41) while the motor (51) is inertially rotating under second conditions. Based on the output of the first sensor (41), the processing of steps (ST24~ST26) is performed.

[0114] At time (t6), the processing of step (ST27) (operation control processing) begins.

[0115] [Second process] The second process is to input the output of the first sensor (41) during the inertial rotation of the electric motor (51) under predetermined conditions that allow for the estimation of the temperature of the magnet (53b). In this example, the second process is a process (demagnetization estimation process) to estimate the degree of demagnetization of the magnet (53b) using the output of the first sensor (41). The second process is performed during trial operation and normal operation (specifically at the start of trial operation and normal operation).

[0116] Next, referring to Figure 7, the process including the second processing by the control unit (45) will be described. In this example, the control unit (45) performs the processing shown in Figure 7 when the condition that the setting of the magnet characteristic map is complete is met. The following steps (ST41 to ST46) are an example of the second processing.

[0117] <Steps (ST31~ST33, ST35)> The processing in steps (ST31-ST33, ST35) is the same as the processing in steps (ST11-ST13, ST15) shown in Figure 4.

[0118] <Steps (ST41~ST44)> In this example, the second start condition is met when all of the following conditions are met: the magnet characteristic map has been set up (the start condition for the process shown in Figure 7), an operation start instruction has been entered (YES in step (ST31)), the operation stop time is longer than a predetermined time (YES in step (ST32)), and the first temperature (T1) and the second temperature (T2) are substantially the same (YES in step (ST33)). The second start condition is the condition for starting the second process.

[0119] When the second start condition is met, the processes in steps (ST41 to ST44) are executed in order. Note that the processes in steps (ST41 to ST44) are the same as the processes in steps (ST21 to ST24) shown in Figure 4.

[0120] <Step (ST45)> Next, the control unit (45) estimates the magnetic flux (Aa) in the second process based on the amplitude and frequency of the induced voltage of the motor (51) detected in step (ST44). Specifically, similar to the process in step (ST25), the control unit (45) estimates the magnetic flux (Aa) in the second process by substituting the above-mentioned amplitude and frequency of the induced voltage into the calculation formula (the calculation formula in the process of step (ST25)).

[0121] Furthermore, the control unit (45) estimates the magnetic flux (Aa) in the first process based on the amplitude and frequency of the induced voltage of the motor (51) detected during the inertial rotation of the motor (51) under the second condition in the first process. Specifically, the memory unit (44) stores the amplitude and frequency of the induced voltage of the motor (51) detected during the inertial rotation of the motor (51) under the second condition in the first process. The control unit (45) estimates the magnetic flux (Aa) in the first process by substituting the above-mentioned amplitude and frequency of the induced voltage stored in the memory unit (44) into the above-mentioned calculation formula (the calculation formula in the process of step (ST25)).

[0122] The control unit (45) then estimates the degree of demagnetization of the magnet (53b) contained in the electric motor (51) based on the difference between the magnetic flux (Aa) in the second process and the magnetic flux (Aa) in the first process. In this example, the control unit (45) estimates the degree of demagnetization of the magnet (53b) as the amount of magnetic flux obtained by subtracting the magnetic flux (Aa) in the second process from the magnetic flux (Aa) in the first process.

[0123] <Step (ST46)> Next, the control unit (45) performs processing according to the estimated degree of demagnetization of the magnet (53b) in step (ST45).

[0124] In this example, the control unit (45) selectively performs operation control processing and demagnetization countermeasure processing depending on the degree of demagnetization of the magnet (53b) estimated in step (ST45). Specifically, if the degree of demagnetization (magnetic flux) of the magnet (53b) exceeds a predetermined threshold, demagnetization countermeasure processing is performed; otherwise, operation control processing is performed.

[0125] The demagnetization handling process includes a notification process to notify that the degree of demagnetization of the magnet (53b) exceeds a threshold (for example, an allowable value in the compressor (21)). For example, in the notification process, the control unit (45) displays a notification image on a display (not shown) to notify that the degree of demagnetization of the magnet (53b) exceeds a threshold. Alternatively, in the notification process, the control unit (45) outputs a notification sound from a speaker (not shown) to notify that the degree of demagnetization of the magnet (53b) exceeds a threshold. Alternatively, in the notification process, the control unit (45) transmits notification information to an external device (not shown) such as a database or server via a network (not shown) to notify that the degree of demagnetization of the magnet (53b) exceeds a threshold.

[0126] [Operation restriction processing] The operation restriction process is a process to limit the operating conditions during normal operation (operation control process) in order to suppress the overheating of the magnet (53b). The operation restriction process is performed during normal operation.

[0127] Next, with reference to Figure 8, the operation restriction processing by the control unit (45) will be described. In this example, the control unit (45) repeatedly performs the following processing at predetermined intervals during normal operation.

[0128] <Step (ST51)> The control unit (45) estimates the magnet temperature (Tm) from the "physical quantities related to the compressor (21)" detected by various sensors (40) based on the estimation model stored in the memory unit (44). Specifically, the control unit (45) derives the magnet temperature (Tm) by inputting the "physical quantities related to the compressor (21)" detected by various sensors (40) into the estimation model.

[0129] <Step (ST52)> Next, the control unit (45) determines whether the magnet temperature (Tm) estimated in step (ST51) is above a predetermined temperature. If the magnet temperature (Tm) is above the predetermined temperature, the process in step (ST53) is performed.

[0130] <Step (ST53)> If the magnet temperature (Tm) is above a predetermined temperature, the control unit (45) restricts the operating conditions in the operation control process so as to suppress the overheating of the magnet (53b). In this example, the control unit (45) reduces the current supplied to the motor (51) in the operation control process. Alternatively, the control unit (45) reduces the rotational speed of the motor (51) in the operation control process. The current supplied to the motor (51) and the rotational speed of the motor (51) are examples of operating conditions in the operation control process.

[0131] [Model Correction Process] The model correction process is a process to correct the estimated model according to the difference between the temperature of the magnet (53b) estimated based on the magnet property map and the temperature of the magnet (53b) estimated based on the estimated model. The model correction process is performed during normal operation (in this example, at the end of normal operation).

[0132] Next, the model correction process performed by the control unit (45) will be explained with reference to Figure 9. In this example, the control unit (45) performs the process shown in Figure 9 during normal operation.

[0133] <Step (ST61)> The control unit (45) determines whether or not an operation stop instruction has been input. If an operation stop instruction has been input, the process in step (ST62) is performed.

[0134] <Step (ST62)> When a stop command is input, the control unit (45) releases the drive of the motor (51) during the low-torque period when the load torque of the compressor (21) is lower than the average load torque of the compressor (21) over one cycle, thereby allowing the motor (51) to rotate by inertia. In other words, the point at which the drive of the motor (51) is released in order to allow the motor (51) to rotate by inertia during the model correction process is the point at which the load torque of the compressor (21) is lower than the average load torque of the compressor (21) over one cycle.

[0135] <Step (ST63)> Next, the control unit (45) inputs the output of the first sensor (41) while the motor (51) is inertial. Specifically, similar to step (ST23), the control unit (45) continues to input the output of the first sensor (41) so that the "output of the first sensor (41) within a predetermined time" necessary for detecting the induced voltage of the motor (51) is obtained. The time for which the output of the first sensor (41) is input is at least a predetermined time.

[0136] <Step (ST64)> Next, the control unit (45) detects the induced voltage of the motor (51) based on the output of the first sensor (41) that is input while the motor (51) is rotating by inertia. In this example, similar to step (ST24), the control unit (45) detects the "line voltage of the motor (51)" obtained by the voltage sensor, which is the first sensor (41), as the induced voltage of the motor (51).

[0137] <Step (ST65)> Next, the control unit (45) estimates the magnetic flux (Aa) based on the amplitude and frequency of the induced voltage of the motor (51) detected in step (ST64). Specifically, similar to the process in step (ST25), the control unit (45) estimates the magnetic flux (Aa) by substituting the above-mentioned amplitude and frequency of the induced voltage into the calculation formula (the calculation formula in the process of step (ST25)).

[0138] The control unit (45) then estimates the magnet temperature (Tm) from the magnet flux (Aa) based on the magnet characteristic map. Hereafter, this magnet temperature (Tm) will be referred to as "magnet temperature (Tm) based on the magnet characteristic map". Note that the above magnet characteristic map is the magnet characteristic map that has been corrected (calibrated) in the first process.

[0139] <Step (ST66)> Furthermore, the control unit (45) derives the magnet temperature (Tm) from physical quantities related to the compressor (21) based on the estimation model. Specifically, the control unit (45) derives the magnet temperature (Tm) by inputting the "physical quantities related to the compressor (21)" detected by various sensors (40) into the estimation model. Hereafter, this magnet temperature (Tm) will be referred to as the "magnet temperature (Tm) based on the estimation model".

[0140] <Step (ST67)> Next, the control unit (45) corrects the estimation model according to the difference between the "magnet temperature (Tm) based on the magnet characteristic map" obtained in step (ST65) and the "magnet temperature (Tm) based on the estimation model" obtained in step (ST66).

[0141] Specifically, the control unit (45) selects from among a plurality of pre-prepared estimation models the estimation model that minimizes (preferably zero) the difference between the magnet temperature (Tm) based on the magnet characteristic map and the magnet temperature (Tm) based on the estimation model, and sets the selected estimation model as the estimation model actually used in various processes such as model correction processing (hereinafter referred to as the "default estimation model").

[0142] For example, if the estimation model is a "regression equation," the control unit (45) may adjust the various coefficients included in the regression equation, which is the estimation model, so that the difference between the magnet temperature (Tm) based on the magnet characteristic map and the magnet temperature (Tm) based on the estimation model becomes small (preferably zero).

[0143] Furthermore, if the estimation model is a "trained model," the control unit (45) may retrain the trained model, which is the estimation model, by performing transfer learning based on new training data in which the "physical quantities related to the compressor (21)" input to the estimation model in step (ST66) are explanatory variables and the "magnet temperature (Tm) based on the magnet property map" estimated in step (ST65) is the target variable, so that the difference between the magnet temperature (Tm) based on the magnet property map and the magnet temperature (Tm) based on the estimation model becomes small (preferably zero).

[0144] [Specific examples of model correction processing] Next, with reference to Figure 10, we will specifically explain the changes in various parameters during the process, including the model correction process. Figure 10 illustrates examples of various parameters, including the rotational speed of the motor (51), the induced voltage of the motor (51), and the load torque of the compressor (21).

[0145] As shown in Figure 10, the compressor (21) periodically repeats the suction stroke and the compression stroke. Therefore, the load torque of the compressor (21) changes periodically.

[0146] At time (t1), a stop command is input to the control unit (45). Time (t1) is not included in the low-torque period when the load torque of the compressor (21) is lower than the average load torque (TRave) of the compressor (21) over one cycle. Therefore, the control unit (45) does not release the drive of the motor (51). Specifically, the control unit (45) continues to control the power converter (35) (specifically, the operation control process) so that the supply of voltage from the power converter (35) to the motor (51) continues.

[0147] Subsequently, when the time (t2) falls within the low-torque period, the control unit (45) controls the power converter (35) so that the voltage supply from the power converter (35) to the motor (51) is stopped. This causes the motor (51) to be disengaged during the low-torque period, and the motor (51) begins to rotate by inertia. The rotational speed of the motor (51) gradually decreases from the rotational speed (R0) in the operation control processing.

[0148] During the period from time (t2) to time (t3), the control unit (45) receives the output of the first sensor (41). Based on the output of the first sensor (41), the processing steps (ST64 to ST67) are performed.

[0149] [Effects of the Embodiment] As described above, in the heat pump system (10) of the embodiment, the control unit (45) drives the stopped motor (51) in the first process under first conditions in which the first temperature (T1) and the second temperature (T2) can be considered to be substantially the same as each other, and then drives the motor (51) by releasing the drive under second conditions in which the first temperature (T1) can be considered to have not substantially changed from the first temperature (T1) under first conditions, thereby allowing the motor (51) to rotate by inertia, and inputs the output of the first sensor (41) while the motor (51) is rotating by inertia under second conditions.

[0150] In the above configuration, if the first temperature (T1) and the second temperature (T2) can be considered to be substantially the same, then the internal temperature of the compressor (21) is substantially uniform when the compressor (21) is stopped, and the temperature of the magnet (53b) of the motor (51) provided in the compressor (21) can be considered to be substantially the same. Therefore, the first and second conditions can be said to be conditions under which the temperature of the magnet (53b) can be considered to be known. Accordingly, based on the output of the first sensor (41) input during the inertial rotation of the motor (51) under the second condition, the induced voltage of the motor (51) can be detected under conditions under which the temperature of the magnet (53b) can be considered to be known. This makes it possible to accurately detect the induced voltage of the motor (51) corresponding to the temperature of the magnet (53b).

[0151] Furthermore, since the induced voltage of the motor (51) corresponding to the temperature of the magnet (53b) can be detected with high accuracy, the relationship between the temperature of the magnet (53b) and the magnetic flux of the magnet (53b) (characteristic curve (L)) can be estimated with high accuracy. As a result, the process of estimating the temperature of the magnet (53b) from the magnetic flux of the magnet (53b) based on the relationship between the temperature of the magnet (53b) and the magnetic flux of the magnet (53b) (characteristic curve (L)) can be performed with high accuracy.

[0152] Furthermore, since the temperature of the magnet (53b) can be accurately estimated from the magnetic flux of the magnet (53b), the estimated model can be accurately corrected during the model correction process. As a result, even if the relationship between the temperature of the magnet (53b) and the magnetic flux of the magnet (53b) (characteristic curve (L)) changes due to manufacturing variations of the magnet (53b) or changes in the internal state of the compressor (21) (manufacturing variations and deterioration), the estimated model can be corrected to match that relationship (characteristic curve (L)). In this way, the magnet characteristic map showing the characteristic curve (L) and the estimated model for estimating the temperature of the magnet (53b) based on physical quantities related to the compressor (21) can be appropriately corrected (calibrated) for each compressor (21).

[0153] Furthermore, in the heat pump system (10) of the embodiment, the first temperature (T1) is the temperature of the discharge pipe (29) provided for discharging the fluid compressed by the compression mechanism (55) from the compressor (21). The second temperature (T2) is the temperature of the air surrounding the compressor (21).

[0154] In the above configuration, the temperature of the discharge pipe (29) changes in accordance with the operation of the compressor (21). If the temperature of the discharge pipe (29) and the temperature of the air surrounding the compressor (21) can be considered to be substantially the same, then when the compressor (21) is stopped, the temperature inside the compressor (21) can be considered to be substantially uniform, and the temperature of the discharge pipe (29), the temperature of the air surrounding the compressor (21), and the temperature of the magnet (53b) of the electric motor (51) provided in the compressor (21) can be considered to be substantially the same.

[0155] Furthermore, in the heat pump system (10) of the embodiment, the inertial rotation of the electric motor (51) in the first process is one rotation or more.

[0156] In the above configuration, the induced voltage of the electric motor (51) can be accurately detected based on the output of the first sensor (41) which is input during the inertial rotation of the electric motor (51) for one or more revolutions.

[0157] Furthermore, in the heat pump system (10) of the embodiment, the first process is performed during a trial run conducted after the installation of the compressor (21).

[0158] In the above configuration, the trial run is performed before normal operation. Therefore, the induced voltage corresponding to the temperature of the magnet (53b) of the motor (51) can be accurately detected before normal operation begins. This allows the relationship between the temperature of the magnet (53b) and the induced voltage of the motor (51) detected during the trial run to be used in the control of normal operation, which is performed after the trial run.

[0159] Furthermore, in the heat pump system (10) of the embodiment, the point at which the drive of the electric motor (51) is released in order to allow the electric motor (51) to rotate by inertia in the first process is the point at which the load torque of the compressor (21) becomes lower than the average load torque of the compressor (21) over one cycle.

[0160] In the above configuration, the output of the first sensor (41) can be input during the inertial rotation of the motor (51) under conditions where the influence of the load torque of the compressor (21) (its influence on the inertial rotation of the motor (51)) is relatively small. This improves the detection accuracy of the induced voltage of the motor (51) corresponding to the temperature of the magnet (53b).

[0161] Furthermore, in the heat pump system (10) of the embodiment, the control unit (45) estimates the relationship between the magnetic flux of the magnet (53b) and the temperature in the first process based on one of the first temperature (T1) under the first conditions, the second temperature (T2) under the first conditions, the first temperature (T1) under the second conditions, and the second temperature (T2) under the second conditions, as well as the amplitude and frequency of the induced voltage of the motor (51) detected during the inertial rotation of the motor (51) under the second conditions.

[0162] In the above configuration, the relationship between the magnetic flux of the magnet (53b) and the temperature of the magnet (53b) can be estimated with high accuracy.

[0163] Furthermore, in the heat pump system (10) of the embodiment, the control unit (45) performs a first process and a second process. After the first process is performed, if the second start condition for starting the second process is met, the second process is performed. In the second process, the control unit (45) drives the motor (51) which is stopped under the first condition, and then releases the drive of the motor (51) under the second condition to allow the motor (51) to rotate by inertia. Based on the amplitude and frequency of the induced voltage of the motor (51) detected during the inertial rotation of the motor (51) under the second condition and the amplitude and frequency of the induced voltage of the motor (51) detected during the inertial rotation of the motor (51) under the second condition in the first process, the control unit (45) estimates the degree of demagnetization of the magnet (53b).

[0164] With the above configuration, the degree of demagnetization of the magnet (53b) can be estimated with high accuracy.

[0165] (Other embodiments) In the above explanation, the following configuration or processing may be used.

[0166] As an example of the first process, a set of steps (ST21~ST26) was given, but it is not limited to this. For example, the first process may include only the set of steps (ST21~ST23), or it may include a set of steps (ST21~ST23) and another process (a process different from the steps (ST24~ST26)). In other words, the first process is a process that includes the process of "driving the motor (51) which is stopped under the first condition, then releasing the drive of the motor (51) under the second condition to allow the motor (51) to rotate by inertia, and inputting the output of the first sensor (41) while the motor (51) is rotating by inertia under the second condition."

[0167] As an example of the first temperature (T1), the temperature of the discharge pipe (29) was given, but it is not limited to this. Other examples of the first temperature (T1) include the temperature of the stator core (52a), the temperature of the coil (52b), and the temperature of the casing (50) of the compressor (21).

[0168] As an example of the second temperature (T2), the temperature of the heat source air delivered to the heat source heat exchanger (23), which is housed in the casing of the outdoor unit (11) together with the compressor (21), was given, but is not limited to this. Other examples of the second temperature (T2) include the temperature of the heat source heat exchanger (23) and the temperature of the electrical component box (not shown) housed in the casing of the outdoor unit (11). Examples of the temperature of the electrical component box include the temperature of the heat sink (not shown) provided in the electrical component box, the temperature of the electrical component circuit board housed in the electrical component box, and the temperature of the refrigerant jacket (not shown) provided in the electrical component box. Examples of the temperature of the electrical component circuit board include the temperature of the intelligent power module (not shown) provided in the electrical component circuit board and the temperature of the reactor (not shown) provided in the electrical component circuit board.

[0169] The "physical quantities relating to the compressor (21)" input to the estimation model may include, in addition to the rotational speed of the electric motor (51) and the temperature of the discharge pipe (29), at least one of the following physical quantities.

[0170] (1) Current flowing through the electric motor (51) (2) At least one of the following pressures: the "suction pressure," which is the pressure of the refrigerant drawn into the compressor (21), and the "discharge pressure," which is the pressure of the refrigerant discharged from the compressor (21), or a physical quantity correlated with at least one of the suction pressure and discharge pressure. (3) Ambient temperature of the compressor (21) (4) The amount of refrigerant oil flowing through the internal space of the compressor (21), or a physical quantity correlated with the amount of refrigerant oil flowing through the internal space of the compressor (21) (5) Total operating time of the compressor (21) (6) The temperature of the inhalation tube (28), or a physical quantity correlated with the temperature of the inhalation tube (28) (7) The amount of heat generated by the coil (52b) of the electric motor (51), or a physical quantity correlated with the amount of heat generated by the coil (52b) of the electric motor (51) The "physical quantity correlated with at least one of the suction pressure and discharge pressure" mentioned above includes the temperature of the refrigerant in a gas-liquid mixture, or a physical quantity correlated with the temperature of the refrigerant in a gas-liquid mixture. The "physical quantity correlated with the amount of heat generated by the coil (52b) of the motor (51)" mentioned above includes the surface temperature of the coil (52b), the resistance of the coil (52b), and the current flowing through the coil (52b).

[0171] As an example of the compression mechanism (55), a rotary type compression mechanism was given, but it is not limited to this. For example, the compression mechanism (55) may be a swing type, scroll type, screw type, turbo type, or other type of compression mechanism.

[0172] The control unit (45) may be located inside the casing housing the compressor (21) (for example, the casing of the outdoor unit (11)), or it may be located outside the casing housing the compressor (21). Furthermore, the control unit (45) may consist of a single processor or multiple processors. The multiple processors may be grouped together in one casing, or they may be located in separate casings. Similarly, the storage unit (44) may consist of a single memory or multiple memories.

[0173] The designations such as "1st," "2nd," and "3rd" mentioned above are used to distinguish between the terms to which these designations are attached, and do not limit the number or order of those terms.

[0174] Furthermore, while embodiments and modifications have been described, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. In addition, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. [Industrial applicability]

[0175] As described above, this disclosure is useful as a technology for controlling heat pump systems. [Explanation of Symbols]

[0176] 10 Heat pump systems 11 Outdoor Unit 12 Indoor Units 20 Refrigerant Circuit 21 Compressor 22 Four-way switching valve 23 Heat source heat exchanger 24 Expansion valve 25 Utilization heat exchanger 26 Heat source fan 27 Users 28 Suction pipe 29 Discharge pipe 30 Control Systems 35 Power converter 40 Various Sensors 41 First Sensor 42. Second Sensor 43 Third Sensor 44 Storage section 45 Control Unit 50 casing 51 Electric motor 52 Stator 53 Rotor 53b Magnet 55 Compression mechanism 56 Drive shaft T1 1st temperature T2 2nd temperature Tm magnet temperature Aa Magnetic flux

Claims

1. A control system for controlling a heat pump system (10) including a compressor (21) having an electric motor (51) having a magnet (53b) and a compression mechanism (55) driven by the electric motor (51), A first sensor (41) is provided to detect the voltage applied to the electric motor (51), A second sensor (42) is provided to detect a first temperature (T1), which is a temperature related to the compressor (21) and changes in accordance with the operation of the compressor (21), A third sensor (43) is provided to detect a second temperature (T2), which is the temperature around the compressor (21) and is different from the first temperature (T1), The system includes a control unit (45) that initiates the first process when a first start condition for initiating the first process is met, In the first process, the control unit (45) drives the stopped motor (51) under a first condition in which the value of the first temperature (T1) and the value of the second temperature (T2) can be considered to be substantially the same as each other, and then releases the drive of the motor (51) under a second condition in which the value of the first temperature (T1) can be considered to have not substantially changed from the value of the first temperature (T1) under the first condition, thereby allowing the motor (51) to rotate by inertia, and inputs the output of the first sensor (41) while the motor (51) is rotating by inertia under the second condition. Control system.

2. In the control system of claim 1, The first temperature (T1) is the temperature of the discharge pipe (29) provided for discharging the fluid compressed by the compression mechanism (55) from the compressor (21), The second temperature (T2) is the temperature of the air surrounding the compressor (21). Control system.

3. In the control system of claim 1, The inertial rotation of the electric motor (51) in the first process is one rotation or more. Control system.

4. In the control system of claim 1, The first process is performed during a trial run conducted after the installation of the compressor (21). Control system.

5. In the control system of claim 1, In the first process, the point at which the drive of the electric motor (51) is released in order to allow the electric motor (51) to rotate by inertia is the point at which the load torque of the compressor (21) becomes lower than the average load torque of the compressor (21) over one cycle. Control system.

6. In the control system of claim 1, In the first process, the control unit (45) estimates the relationship between the magnetic flux of the magnet (53b) and the temperature based on one of the first temperature (T1) under the first conditions, the second temperature (T2) under the first conditions, the first temperature (T1) under the second conditions, and the amplitude and frequency of the induced voltage of the motor (51) detected during the inertial rotation of the motor (51) under the second conditions. Control system.

7. In the control system of claim 1, The control unit (45) performs the first process and the second process, After the first process is performed, if the second start condition for starting the second process is met, the second process is performed. The control unit (45) in the second process, After driving the motor (51) which is stopped under the first condition, the motor (51) is allowed to rotate by inertia by releasing the drive to the motor (51) under the second condition. Based on the amplitude and frequency of the induced voltage of the motor (51) detected during the inertial rotation of the motor (51) under the second condition, and the amplitude and frequency of the induced voltage of the motor (51) detected during the inertial rotation of the motor (51) under the second condition in the first process, the degree of demagnetization of the magnet (53b) is estimated. Control system.

8. A heat pump system comprising any one of claims 1 to 7.

9. A control method for controlling a heat pump system (10) including a compressor (21) having an electric motor (51) having a magnet (53b) and a compression mechanism (55) driven by the electric motor (51), A first step (ST21, ST22) is to drive the stopped motor (51) under a first condition in which the value of a first temperature (T1), which is a temperature related to the compressor (21) and a temperature that changes in accordance with the driving of the compressor (21), and the value of a second temperature (T2), which is the temperature around the compressor (21) and a temperature different from the first temperature (T1), can be considered to be substantially the same as each other, and then to release the drive of the motor (51) under a second condition in which the value of the motor (51) can be considered to have not substantially changed from the value of the first temperature (T1) under the first condition, thereby allowing the motor (51) to rotate by inertia, The method comprises a second step (ST23) of detecting the voltage applied to the electric motor (51) during the inertial rotation of the electric motor (51) under the second condition described above. Control method.

10. A control program that causes a computer to execute the control method of claim 9.

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