Compressor performance testing device

Abstract

This disclosure provides a compressor performance testing apparatus capable of quickly converging the temperature in a tank in which an evaporator is located and which is filled with a secondary refrigerant. [Solution] A performance testing apparatus for a compressor, comprising: a tank filled with a secondary refrigerant heated by a heater; a condenser supplied with refrigerant discharged from the compressor and cooling the refrigerant; an expansion valve that reduces the pressure of the refrigerant discharged from the condenser; an evaporator located in the tank and supplied with the refrigerant discharged from the expansion valve and heated by the secondary refrigerant; and a control unit that adjusts the heater output of the heater and the valve opening degree of the expansion valve based on the temperature of the tank.

Description

Technical Field

[0001] The present disclosure relates to a performance test apparatus for a compressor.

Background Art

[0002] Patent Document 1 discloses a compressor capacity test apparatus that compresses a refrigerant with a compressor, condenses it with a condenser, expands it with an expansion valve, evaporates it with an evaporator, and circulates it back to the compressor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a performance test apparatus for a compressor used in a refrigeration device or the like, a secondary refrigerant type performance test apparatus is known. The secondary refrigerant type performance test apparatus controls so that each of the discharge pressure, suction pressure, temperature before the expansion valve, and suction temperature in the refrigeration cycle becomes constant under certain conditions. Then, the secondary refrigerant type performance test apparatus calculates the performance of the compressor from the heater input required for the heat balance of the evaporator when each of the discharge pressure, suction pressure, temperature before the expansion valve, and suction temperature in the refrigeration cycle becomes constant.

[0005] In a secondary refrigerant type performance test apparatus, a tank in which an evaporator is arranged and filled with a secondary refrigerant is used. In the tank filled with the secondary refrigerant, it is required to shorten the time until the temperature converges to a desired temperature.

[0006] The present disclosure provides a performance test apparatus for a compressor capable of converging the temperature in a tank in which an evaporator is arranged and filled with a secondary refrigerant in a short time.

Means for Solving the Problems

[0007] The performance testing apparatus from the first perspective is: A compressor performance testing device, A tank for filling with a secondary refrigerant that is heated by a heater, A condenser is supplied with refrigerant discharged from the compressor and used to cool the refrigerant, An expansion valve is provided which the refrigerant discharged from the condenser is depressurized, An evaporator is located inside the tank and is supplied with the refrigerant discharged from the expansion valve, and heats the refrigerant with the secondary refrigerant. A control unit that adjusts the heater output of the heater and the valve opening degree of the expansion valve based on the temperature of the tank, It is equipped with.

[0008] According to the performance test apparatus described in the first perspective, it is possible to accelerate the convergence of the tank temperature, which is the rate-limiting factor in the stabilization of the conditions.

[0009] The performance test apparatus from the second perspective is the performance test apparatus from the first perspective in which the control unit adjusts the heater output based on the intake temperature in the compressor.

[0010] According to the performance testing apparatus from the second perspective, it is possible to accelerate the convergence of the tank temperature, which is the rate-limiting factor in the stabilization of the conditions.

[0011] The third performance test apparatus is a first or second performance test apparatus in which the control unit controls the expansion valve to a second valve opening that is lower than the first valve opening corresponding to the target pressure of the suction pressure in the compressor when the temperature of the secondary refrigerant is a first temperature or higher than the target temperature, and then controls the expansion valve to the first valve opening.

[0012] According to the third-party performance testing apparatus, the convergence of the tank temperature, which is the rate-limiting factor in stabilizing the conditions, can be accelerated.

[0013] The performance test apparatus of the fourth perspective is a performance test apparatus of the third perspective in which the control unit controls the expansion valve to open to the second valve, and then controls the expansion valve to open to the first valve when the temperature of the secondary refrigerant falls to or below the second temperature, which is closer to the target temperature than the first temperature.

[0014] According to the performance testing apparatus from the fourth perspective, it is possible to accelerate the convergence of the tank temperature, which is the rate-limiting factor in the stabilization of the conditions.

[0015] The fifth performance test apparatus is a third or fourth performance test apparatus in which the control unit controls the heater so that the output corresponds to the evaporation temperature of the refrigerant at the second valve opening when the expansion valve is open to the second valve opening, and controls the heater so that the output corresponds to the evaporation temperature of the refrigerant at the first valve opening when the expansion valve is open to the first valve opening.

[0016] According to the performance test apparatus described in the fifth perspective, it is possible to accelerate the convergence of the tank temperature, which is the rate-limiting factor in the stabilization of the conditions.

[0017] The performance test apparatus of the sixth perspective is a performance test apparatus of any of the first to fifth perspectives, in which the control unit controls the heater in the evaporator to achieve a predetermined degree of superheating.

[0018] According to the performance testing apparatus of the sixth perspective, the degree of overheating can be further controlled.

[0019] The performance test apparatus of the seventh aspect is a performance test apparatus of any of the first to sixth aspects, wherein the condenser is cooled by a coolant controlled to a predetermined temperature.

[0020] According to the performance test apparatus in the seventh aspect, the condenser can stably cool the refrigerant.

[0021] The performance test apparatus of the eighth aspect is the performance test apparatus of the seventh aspect, further comprising a control valve for controlling the flow rate of the coolant.

[0022] According to the performance test apparatus of the eighth aspect, in the condenser, the refrigerant can be stably cooled.

[0023] The performance test apparatus of the ninth aspect is the performance test apparatus of any one of the first aspect to the eighth aspect, further comprising a temperature adjustment unit that adjusts the temperature of the refrigerant supplied to the expansion valve.

[0024] According to the performance test apparatus of the ninth aspect, the superheat degree can be controlled.

[0025] The performance test apparatus of the tenth aspect is the performance test apparatus of the ninth aspect, wherein the temperature adjustment unit includes a water tank that stores a second coolant and a second heater that heats the second coolant.

[0026] According to the performance test apparatus of the tenth aspect, the superheat degree can be controlled.

[0027] The performance test apparatus of the eleventh aspect is the performance test apparatus of any one of the first aspect to the tenth aspect, wherein the control unit controls the valve opening degree of the expansion valve by model predictive control.

[0028] According to the performance test apparatus of the eleventh aspect, the convergence of the tank temperature, which is the rate-determining factor for conditional stability, can be accelerated.

[0029] The performance test apparatus of the twelfth aspect is the performance test apparatus of the eleventh aspect, wherein the control unit determines the operation amount of the actuator that controls the opening degree of the expansion valve by model predictive control.

[0030] According to the performance test apparatus of the twelfth aspect, the convergence of the tank temperature, which is the rate-determining factor for conditional stability, can be accelerated.

[0031] The performance test apparatus of the thirteenth aspect is the performance test apparatus of the eleventh aspect, wherein the control unit determines the target value of the actuator that controls the opening degree of the expansion valve by model predictive control, and the operation amount of the actuator is determined by PID control.

[0032] According to the performance test apparatus described in the 13th perspective, the convergence of the tank temperature, which is the rate-limiting factor in stabilizing the conditions, can be accelerated.

[0033] The performance test apparatus of the 14th viewpoint is a performance test apparatus of either the 11th viewpoint or the 13th viewpoint that uses a model that predicts changes in state between the manipulated variables and the controlled variables, with the valve opening and heater output being manipulated variables and the intake pressure, intake temperature and tank temperature being controlled variables in the model predictive control.

[0034] According to the performance test apparatus described in the 14th perspective, the convergence of the tank temperature, which is the rate-limiting factor in stabilizing the conditions, can be accelerated. [Brief explanation of the drawing]

[0035] [Figure 1] Figure 1 is a schematic diagram of a performance testing apparatus according to the first embodiment. [Figure 2] Figure 2 is a hardware configuration diagram illustrating the hardware configuration of the control unit in the performance test apparatus according to the first embodiment. [Figure 3] Figure 3 is a flowchart illustrating the processing of the control unit in the performance test apparatus according to the first embodiment. [Figure 4] Figure 4 is a diagram illustrating the operation of the performance testing apparatus according to the first embodiment. [Figure 5] Figure 5 is a flowchart illustrating the processing of the control unit in the performance test apparatus according to the second embodiment. [Figure 6] Figure 6 is a diagram illustrating the operation of the performance testing apparatus according to the second embodiment. [Modes for carrying out the invention]

[0036] <First Embodiment> A specific example of a performance testing apparatus according to the first embodiment will be described below with reference to the drawings. However, this disclosure is not limited to these examples, and all modifications within the meaning and scope of the claims are intended to be included.

[0037] In addition, regarding the descriptions and drawings of each embodiment, components having substantially the same or corresponding functional configurations may be denoted by the same reference numerals, thereby omitting redundant explanations. Furthermore, for ease of understanding, the scale of each part in the drawings may differ from the actual scale.

[0038] A performance testing apparatus according to the first embodiment will now be described. The performance testing apparatus according to the first embodiment is a performance testing apparatus for a compressor used in a refrigerator or the like. The performance testing apparatus according to the first embodiment includes a tank filled with a secondary refrigerant heated by a heater, a condenser to which refrigerant discharged from the compressor is supplied and which cools the refrigerant, and an expansion valve to which the refrigerant discharged from the condenser is depressurized. The performance testing apparatus according to the first embodiment also includes an evaporator located inside the tank and to which refrigerant discharged from the expansion valve is supplied and which heats the refrigerant with the secondary refrigerant, and a control unit that adjusts the heater output of the heater and the valve opening degree of the expansion valve based on the temperature of the tank.

[0039] Figure 1 is a schematic diagram of a performance testing apparatus 1, which is an example of a performance testing apparatus according to the first embodiment.

[0040] Performance test apparatus 1 is a performance test apparatus for testing the performance of a compressor DUT. The compressor DUT inhales refrigerant R in a low-pressure gaseous state. The compressor DUT then compresses the inhaled refrigerant R and discharges it as a high-pressure gaseous state. Examples of compressor DUTs include rotary compressors, scroll compressors, screw compressors, and turbo compressors.

[0041] The performance test apparatus 1 comprises a condenser 10, an expansion valve 20, and an evaporator 30. The performance test apparatus 1 forms a refrigeration cycle by circulating the refrigerant R through the compressor DUT, condenser 10, expansion valve 20, and evaporator 30. The performance test apparatus 1 also comprises a tank 40 and a temperature control unit 50. Furthermore, the performance test apparatus 1 comprises a thermometer 61, a pressure gauge 62, a thermometer 63, a pressure gauge 64, and a thermometer 65. The performance test apparatus 1 also comprises a control unit 80 that controls the entire performance test apparatus 1.

[0042] The individual components of the performance testing apparatus 1 will be described in detail below.

[0043] (Condenser 10) The condenser 10 cools the high-pressure gaseous refrigerant R supplied from the compressor DUT. The gaseous refrigerant R condenses into a liquid state when cooled in the condenser 10. The condenser 10 performs heat exchange between the refrigerant R and the coolant W1. The condenser 10 cools the refrigerant R by performing heat exchange between the refrigerant R and the coolant W1.

[0044] The coolant W1 is controlled to a predetermined temperature in order to cool the refrigerant R. The flow rate of the coolant W1 is also regulated by a control valve 11. The valve opening of the control valve 11 is controlled by a control unit 80. The coolant W1 can be, for example, water or brine.

[0045] (Expansion valve 20) The expansion valve 20 reduces the pressure of the refrigerant R, which has been condensed into a liquid state by the condenser 10. The expansion valve 20 is, for example, an electrically operated valve with an adjustable opening. The valve opening of the expansion valve 20 is controlled by the control unit 80. The flow rate of the refrigerant R is controlled by the opening of the expansion valve 20.

[0046] (Evaporator 30) The evaporator 30 heats the refrigerant R discharged from the expansion valve 20. The liquid refrigerant R is heated in the evaporator 30, causing it to evaporate and become a gaseous refrigerant R.

[0047] The evaporator 30 is placed inside the tank 40. The evaporator 30 is composed of, for example, direct expansion coils. The evaporator 30 may also be composed of parallel direct expansion coils. The secondary refrigerant R2 is filled into the tank 40. The evaporator 30 performs heat exchange between the refrigerant R and the secondary refrigerant R2. The evaporator 30 heats the refrigerant R by performing heat exchange between the refrigerant R and the secondary refrigerant R2.

[0048] (Tank 40) Tank 40 is an airtight tank filled with secondary refrigerant R2. Tank 40 is also an insulated tank. The secondary refrigerant R2 is, for example, R134a.

[0049] Tank 40 contains an evaporator 30 and a heater 41. The evaporator 30 is located at the top of tank 40. The heater 41 is located at the bottom of tank 40 so as to be sufficiently submerged below the liquid level of the secondary refrigerant R2. In other words, the tank 40 is filled with enough secondary refrigerant R2 to sufficiently submerge the heater 41 below the liquid level.

[0050] The power supply unit 42 supplies power to the heater 41. The heater 41 heats the secondary refrigerant R2 using the power supplied from the power supply unit 42. The heater output of the heater 41 is controlled by the power supplied from the power supply unit 42. The power supplied to the heater 41 by the power supply unit 80 is controlled by the power supply unit 42.

[0051] (Temperature adjustment section 50) The temperature control unit 50 cools the liquid refrigerant R discharged from the condenser 10. The temperature control unit 50 cools the refrigerant R so that its degree of subcooling reaches a desired degree.

[0052] The temperature control unit 50 comprises a water tank 51, a heater 52, and a power supply unit 53. The water tank 51 stores the coolant W2.

[0053] The temperature control unit 50 performs heat exchange between the refrigerant R and the coolant W2 in the water tank 51. The temperature control unit 50 cools the refrigerant R by performing heat exchange between the refrigerant R and the coolant W2.

[0054] The coolant W2 is controlled to a predetermined temperature by the heater 52. The power supply unit 53 supplies power to the heater 52. The heater 52 heats the coolant W2 with the power supplied from the power supply unit 53. The heater output of the heater 52 is controlled by the power supplied from the power supply unit 53. The power supplied to the heater 52 by the control unit 80 is controlled by the power supply unit 53. The coolant W2 is, for example, water, brine, etc.

[0055] Note that coolant W2 is an example of a second coolant, and heater 52 is an example of a second heater.

[0056] (thermometer 61) The thermometer 61 measures the temperature of the tank 40. The thermometer 61 outputs the measured temperature of the tank 40 to the control unit 80.

[0057] (Pressure gauge 62) The pressure gauge 62 measures the pressure (discharge pressure) of the refrigerant R discharged from the compressor DUT. The pressure gauge 62 outputs the measured discharge pressure to the control unit 80.

[0058] (thermometer 63) The thermometer 63 measures the temperature of the refrigerant R supplied to the expansion valve 20 (temperature before the expansion valve). The thermometer 63 outputs the measured temperature of the refrigerant R supplied to the expansion valve 20 to the control unit 80.

[0059] (Pressure gauge 64) The pressure gauge 64 measures the pressure (suction pressure) of the refrigerant R drawn into the compressor DUT. The pressure gauge 64 outputs the measured suction pressure to the control unit 80.

[0060] (thermometer 65) The thermometer 65 measures the temperature of the refrigerant R (intake temperature) drawn into the compressor DUT. The thermometer 65 outputs the measured intake temperature to the control unit 80.

[0061] (Control unit 80) The control unit 80 controls the entire performance test apparatus 1. The control unit 80 controls the control valve 11, the expansion valve 20, the power supply unit 42, and the power supply unit 53. The control unit 80 also acquires measurement results from the thermometer 61, pressure gauge 62, thermometer 63, pressure gauge 64, and thermometer 65.

[0062] The hardware configuration of the control unit 80 will now be described. Figure 2 is a hardware configuration diagram illustrating the hardware configuration of the control unit 80 in the performance test apparatus 1, which is an example of a performance test apparatus according to the first embodiment.

[0063] The control unit 80 comprises a control unit 81, a RAM (Random Access Memory) 82, and a ROM (Read Only Memory) 83. The control unit 80 also includes a storage interface 84 and an external interface 85. The control unit 81, RAM 82, ROM 83, storage interface 84, and external interface 85 are each connected to bus B1.

[0064] For example, a storage medium 84a is connected to the storage I / F 84. For example, the control valve 11, the expansion valve 20, the power supply unit 42, and the power supply unit 53 are each connected to the external I / F 85.

[0065] The control unit 81 is a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 81 may also be an ASIC (application specific integrated circuit) or an FPGA (Field-Programmable Gate Array). The control unit 81 executes a program, thereby performing each of the processes described herein. The control unit 81 is an arithmetic unit that reads a program (app, application) from a storage device such as a ROM 83 or a storage medium 84a onto the RAM 82 and executes the processing. The control unit 81, RAM 82, and ROM 83 constitute a computer that controls the performance test device 1.

[0066] RAM82 is a volatile semiconductor memory that temporarily holds programs (apps, applications), for example.

[0067] ROM83 is a non-volatile semiconductor memory that can retain programs (apps, applications, etc.) even when the power is turned off. ROM83 stores programs such as the BIOS (Basic Input / Output System) that are executed at startup, as well as various settings such as OS (Operating System) settings and network settings.

[0068] The storage I / F84 is an interface with external storage devices such as storage medium 84a.

[0069] Storage media 84a include, for example, SD (Secure Digital) memory cards, USB (Universal Serial Bus) memory, HDDs (Hard Disk Drives), and SSDs (Solid State Drives).

[0070] The external interface 85 is an interface that connects peripheral devices to the control unit 81. Through the external interface 85, the control unit 81 connects to the control valve 11, the expansion valve 20, the power supply unit 42, and the power supply unit 53, respectively.

[0071] Next, the processing performed by the control unit 81 in the control unit 80 will be described. Figure 3 is a flowchart illustrating the processing performed by the control unit 81 in the performance test apparatus 1, which is an example of a performance test apparatus according to the first embodiment. Figure 4 is a diagram illustrating the operation of the performance test apparatus 1, which is an example of a performance test apparatus according to the first embodiment.

[0072] In Figure 4(a), the horizontal axis represents time, and the vertical axis represents the suction pressure at the compressor DUT. Pressure Pt represents the target suction pressure. In Figure 4(b), the horizontal axis represents time, and the vertical axis represents the valve opening at the expansion valve 20. Valve opening VD1 represents the valve opening when the suction pressure is pressure Pt. In Figure 4(c), the horizontal axis represents time, and the vertical axis represents the tank temperature at the tank 40. Temperature Tt represents the target tank temperature. In Figures 4(a), (b), and (c), the horizontal axis represents time.

[0073] The following explanation describes the case where the temperature of the tank 40 is above a first temperature, which is higher than the target temperature for the tank temperature, and the control unit 80 controls the tank to lower the tank temperature.

[0074] (Step S10) The control unit 81 controls the valve opening of the expansion valve 20 so that the discharge pressure in the compressor DUT, as measured by the pressure gauge 64, becomes less than the target value. Specifically, as shown in Figure 4(b), the control unit 81 controls the valve opening of the expansion valve 20 to a valve opening VD2 which is smaller than the valve opening VD1, so that the suction pressure becomes lower than the target pressure Pt.

[0075] Furthermore, when the valve opening of the expansion valve 20 is at valve opening VD2, the control unit 81 controls the heater 41 by controlling the power supply unit 42 so that the heater output corresponds to the evaporation temperature of the refrigerant R at valve opening VD2. The control unit 81 controls the heater 41 by controlling the power supply unit 42 so that the evaporator 30 reaches a predetermined degree of superheating.

[0076] The control unit 81 controls the expansion valve 20 so that the valve opening VD2 is smaller than the valve opening VD1, as shown by line L2 in Figure 4(b). When the valve opening of the expansion valve 20 is set to valve opening VD2, the suction pressure becomes lower than the target pressure Pt, as shown by line L1 in Figure 4(a). By lowering the suction pressure in the compressor DUT, heat exchange between the refrigerant R and the secondary refrigerant R2 in the evaporator 30 is promoted. By promoting heat exchange between the refrigerant R and the secondary refrigerant R2 in the evaporator 30, the temperature of the tank 40 can be lowered more quickly, as shown by line L3 in Figure 4(c).

[0077] In Figure 4(b), as shown by line L2z, the suction pressure when the valve opening of the expansion valve 20 is controlled to valve opening VD1 from the beginning is shown by line L1z in Figure 4(a). Also, in Figure 4(b), as shown by line L2z, the tank temperature when the valve opening of the expansion valve 20 is controlled to valve opening VD1 from the beginning is shown by line L3z in Figure 4(c).

[0078] As is clear from comparing lines L3 and L3z in Figure 4(c), by setting the valve opening of the expansion valve 20 to a valve opening VD2 which is smaller than the valve opening VD1, the tank temperature in the tank 40 can be stabilized more quickly. In other words, the performance test apparatus 1 can converge the temperature in the tank 40 in a short time by setting the valve opening of the expansion valve 20 to a valve opening VD2 which is smaller than the valve opening VD1.

[0079] Note that valve opening VD1 is an example of the first valve opening, and valve opening VD2 is an example of the second valve opening.

[0080] (Step S20) Next, the control unit 81 determines whether the tank temperature in the tank 40 is within predetermined conditions. Specifically, the control unit 81 obtains the tank temperature in the tank 40 from the thermometer 61. Then, the control unit 81 determines whether the obtained tank temperature is within predetermined conditions. For example, the control unit 81 determines whether the temperature is within a predetermined temperature range with respect to the target tank temperature Tt, for example, whether it is below a second temperature that is lower than a first temperature but higher than the target temperature.

[0081] If the tank temperature is within the predetermined conditions (YES in step S20), the control unit 81 proceeds to step S30. If the tank temperature is not within the predetermined conditions (NO in step S20), the control unit 81 returns to step S10 and repeats the process.

[0082] (Step S30) If the tank temperature is within the predetermined conditions (YES in step S20), the control unit 81 controls the valve opening of the expansion valve 20 so that the discharge pressure in the compressor DUT, as measured by the pressure gauge 64, approaches the target value. Specifically, as shown in Figure 4(b), the valve opening of the expansion valve 20 is controlled to a valve opening VD1 so that the suction pressure becomes the target pressure Pt.

[0083] Furthermore, when the valve opening of the expansion valve 20 is at valve opening VD1, the control unit 81 controls the heater 41 by controlling the power supply unit 42 so that the heater output corresponds to the evaporation temperature of the refrigerant R at valve opening VD1. The control unit 81 controls the heater 41 by controlling the power supply unit 42 so that the evaporator 30 reaches a predetermined degree of superheating.

[0084] As shown by line L2 in Figure 4(b), at time t1, the control unit 81 controls the expansion valve 20 to change the valve opening of the expansion valve 20 from valve opening VD2 to valve opening VD1.

[0085] (Step S40) Next, the control unit 81 determines whether the tank temperature and suction pressure in the tank 40 are within predetermined conditions. Specifically, the control unit 81 obtains the tank temperature in the tank 40 from the thermometer 61. Then, the control unit 81 determines whether the obtained tank temperature is within predetermined conditions. For example, the control unit 81 determines whether the target tank temperature, temperature Tt, is within a predetermined temperature range. The control unit 81 also obtains the suction pressure in the compressor DUT from the pressure gauge 64. Then, the control unit 81 determines whether the obtained suction pressure is within predetermined conditions.

[0086] If both the tank temperature and the suction pressure are within the predetermined conditions (YES in step S40), the control unit 81 terminates the process. If at least one of the tank temperature and the suction pressure is not within the predetermined conditions (NO in step S40), the control unit 81 returns to step S30 and repeats the process.

[0087] As is clear from comparing lines L1 and L1z in Figure 4(a), the suction pressure can be stabilized quickly by first setting the valve opening of the expansion valve 20 to a smaller valve opening VD2 than the valve opening VD1, and then to VD1. In other words, the performance test device 1 can converge the suction pressure in the compressor DUT in a short time by first setting the valve opening of the expansion valve 20 to a smaller valve opening VD2 than the valve opening VD1, and then to VD1.

[0088] According to the performance test apparatus of the first embodiment, the convergence of the tank temperature can be accelerated.

[0089] <Second Embodiment> A performance testing apparatus according to the second embodiment will now be described. In the performance testing apparatus according to the second embodiment, the control unit performs control by model predictive control, in addition to the control unit in the performance testing apparatus according to the first embodiment.

[0090] Since the processing in the control unit of the performance test apparatus according to the second embodiment differs from that of the performance test apparatus according to the first embodiment, the processing related to the performance test apparatus according to the second embodiment will be explained using the control unit 81 of the performance test apparatus 1.

[0091] Figure 5 is a flowchart illustrating the processing of the control unit in the performance test apparatus according to the second embodiment. Here, the control unit 81 in the performance test apparatus 1 will be used as the basis for the explanation.

[0092] (Step S110) First, the control unit 81 obtains the discharge pressure in the compressor DUT from the pressure gauge 62.

[0093] (Step S120) Next, the control unit 81 obtains the suction pressure in the compressor DUT from the pressure gauge 64.

[0094] (Step S130) Next, the control unit 81 obtains the temperature in front of the expansion valve 20 from the thermometer 63.

[0095] (Step S140) Next, the control unit 81 obtains the suction temperature in the compressor DUT from the thermometer 65.

[0096] (Step S150) Next, the control unit 81 obtains the tank temperature in the tank 40 from the thermometer 61.

[0097] (Step S160) Next, the control unit 81 determines whether all state quantities acquired in each of steps S110, S120, S130, S140, and S150 fall within the set error range. If all state quantities fall within the set error range (YES in step S160), the control unit 81 terminates the process. If at least one of the state quantities does not fall within the set error range (NO in step S160), the control unit 81 proceeds to step S170.

[0098] (Step S170) The control unit 81 simultaneously determines the manipulated variables using model predictive control, utilizing all state variables acquired in each of steps S110, S120, S130, S140, and S150. Specifically, the control unit 81 controls the valve opening of the expansion valve 20, the valve opening of the control valve 11, the heater output of the heater 41, and the heater output of the heater 52, respectively, using model predictive control. In other words, in model predictive control, the control unit 81 uses all state variables acquired in each of steps S110, S120, S130, S140, and S150 as manipulated variables. Furthermore, in model predictive control, the control unit 81 uses the valve opening of the expansion valve 20, the valve opening of the control valve 11, the heater output of the heater 41, and the heater output of the heater 52 as controlled variables. The control unit 81 then performs model predictive control using a model that predicts the change in state between the manipulated variables and the controlled variables.

[0099] Model-based predictive control models the behavior resulting from the operation of multiple actuators and simultaneously determines the manipulated variable according to the current state variable.

[0100] Once the control unit 81 has determined the manipulated variable, it proceeds to step S180.

[0101] (Step S180) The control unit 81 controls the valve opening of the expansion valve 20 to the valve opening determined in step S170.

[0102] (Step S190) Next, the control unit 81 controls the valve opening of the control valve 11 to the valve opening determined in step S170.

[0103] (Step S200) Next, the control unit 81 controls the heater output of the heater 41 to the heater output determined in step S170.

[0104] (Step S210) Next, the control unit 81 controls the heater output of the heater 52 to the heater output determined in step S170. Then, the control unit 81 returns to step S110 and repeats the process.

[0105] Next, the operation of the performance testing apparatus according to the second embodiment will be described. Figure 6 is a diagram illustrating the operation of the performance testing apparatus according to the second embodiment.

[0106] In Figure 6, the horizontal axis represents time (in minutes (min)) and the vertical axis represents intake temperature (in degrees Celsius (°C)). Line L4 shows the operating results of the performance test apparatus according to the second embodiment, and line L4z shows the operating results of the performance test apparatus of the reference example. In the performance test apparatus of the reference example, state variables are controlled by each actuator.

[0107] As shown by line L4, the settling time A can be reduced to half compared to the settling time Az in the reference example. Similarly, the stabilization time B can also be reduced to half compared to the stabilization time Bz due to the reduction in hunting.

[0108] In the performance test apparatus 1, the valve opening of the expansion valve 20, the valve opening of the control valve 11, the heater output of the heater 41, and the heater output of the heater 52 may interfere with each other. In other words, the performance test apparatus 1 is a system in which mutual interference occurs.

[0109] In the performance test apparatus 1, which is a system of mutual interference, if the actuators are controlled individually to control each state variable so that it becomes a desired state variable, it takes a long time for the system to converge.

[0110] In the performance testing apparatus according to the second embodiment, the convergence of the system can be improved by performing control using model predictive control. Furthermore, in the performance testing apparatus according to the second embodiment, the allowable error can be reduced by performing control using model predictive control.

[0111] In the example above, the control unit 81 controlled the valve opening of the expansion valve 20, the valve opening of the control valve 11, the heater output of the heater 41, and the heater output of the heater 52, respectively. However, target values ​​may be determined, and the operating values ​​may be determined by PID control.

[0112] Although embodiments have been described above, it will be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims. Various modifications and improvements are possible, such as combinations or substitutions with parts or all of other embodiments. [Explanation of Symbols]

[0113] 1. Performance testing equipment 10 Condenser 11 Control valve 20 Expansion valve 30 Evaporator 40 tanks 41 Heater 42 Power Supply Units 50 Temperature control section 51 Aquariums 52 Heater 53 Power supply unit 61, 63, 65 thermometer 64, 62 Pressure gauge 80 Control Unit 81 Control Unit DUT Compressor R refrigerant R2 Secondary refrigerant VD1, VD2 valve opening W1, W2 Coolant

Claims

1. A performance test apparatus (1) for a compressor (DUT), A tank (40) for filling with secondary refrigerant (R2) heated by a heater (41), A condenser (10) is supplied with refrigerant (R) discharged from the compressor (DUT) and cools the refrigerant (R), An expansion valve (20) in which the refrigerant (R) discharged from the condenser (10) is depressurized, An evaporator (30) is located inside the tank (40) and is supplied with the refrigerant (R) discharged from the expansion valve (20), and heats the refrigerant (R) with the secondary refrigerant (R2), A control unit (81) adjusts the heater output of the heater (41) and the valve opening degree of the expansion valve (20) based on the temperature of the tank (40), Equipped with, Performance testing apparatus (1).

2. The control unit (81) adjusts the heater output based on the suction temperature in the compressor (DUT). The performance testing apparatus (1) according to claim 1.

3. When the temperature of the secondary refrigerant (R2) is above a first temperature which is higher than the target temperature, the control unit (81) controls the expansion valve (20) so that the valve opening is lower than a second valve opening (VD2) which is lower than a first valve opening (VD1) which corresponds to the target pressure of the suction pressure in the compressor (DUT), and then controls the expansion valve (20) so that it is the first valve opening (VD1). The performance testing apparatus (1) according to claim 1.

4. The control unit (81) controls the expansion valve (20) to the second valve opening (VD2), and then controls the expansion valve (20) to the first valve opening (VD1) when the temperature of the secondary refrigerant (R2) falls below the second temperature, which is closer to the target temperature than the first temperature. The performance testing apparatus (1) according to claim 3.

5. The control unit (81) When the opening of the expansion valve (20) is at the second valve opening (VD2), the heater (41) is controlled to produce an output corresponding to the evaporation temperature of the refrigerant (R) at the second valve opening (VD2). When the opening of the expansion valve (20) is at the first valve opening (VD1), the heater (41) is controlled to produce an output corresponding to the evaporation temperature of the refrigerant (R) at the first valve opening (VD1). The performance testing apparatus (1) according to claim 3.

6. The control unit (81) controls the heater (41) in the evaporator (30) to achieve a predetermined degree of superheating. The performance testing apparatus (1) according to claim 1.

7. The condenser (10) is cooled by a coolant (W1) controlled to a predetermined temperature. The performance testing apparatus (1) according to claim 1.

8. The system further includes a control valve (11) for controlling the flow rate of the coolant (W1). The performance testing apparatus (1) according to claim 7.

9. The system further includes a temperature control unit (50) for adjusting the temperature of the refrigerant (R) supplied to the expansion valve (20). The performance testing apparatus (1) according to claim 1.

10. The temperature control unit (50) includes a water tank (51) for storing a second coolant (W2) and a second heater (52) for heating the second coolant (W2). The performance testing apparatus (1) according to claim 9.

11. The control unit (81) controls the valve opening degree of the expansion valve (20) by model predictive control. A performance testing apparatus (1) according to any one of claims 1 to 10.

12. The control unit (81) determines the amount of operation of the actuator that controls the opening degree of the expansion valve (20) by model predictive control. The performance testing apparatus (1) according to claim 11.

13. The control unit (81) determines the target value of the actuator that controls the opening degree of the expansion valve (20) by model predictive control, and the amount of the actuator to be operated is determined by PID control. The performance testing apparatus (1) according to claim 11.

14. In the aforementioned model predictive control, the valve opening and heater output are used as manipulated variables, and the intake pressure, intake temperature, and tank temperature are used as controlled variables. A model is used to predict the change in state between the manipulated variables and the controlled variables. The performance testing apparatus (1) according to claim 11.

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