Compressor control system and control method thereof

Abstract

The application discloses a compressor control system and a control method in a refrigeration system, the refrigeration system comprising a compressor and an economizer, wherein the compressor comprises a slide valve, the economizer has an inlet pipe, a gas outlet pipe and a liquid outlet pipe, the compressor control system comprises: an inlet pipe sensor; a gas outlet pipe sensor; a liquid outlet pipe sensor; and a control device configured to: receive pressure parameters and temperature parameters of the inlet pipe, the gas outlet pipe and the liquid outlet pipe; control the movement of the slide valve based on the pressure parameters and the temperature parameters, so as to adjust the position of the slide valve. The application reflects the change of the actual volume ratio of the compressor through the change of the mass and density of the refrigerant discharged from the exhaust port of the compressor. The influence of the pressure drop of the economizer pipeline design is avoided, so that the calibration result of the volume ratio of the compressor is more accurate and reliable.

Description

Technical Field

[0001] This application relates to the field of refrigeration systems, and in particular to a compressor control system and control method in a refrigeration system. Background Technology

[0002] Screw compressors are common components in refrigeration systems. A screw compressor utilizes the meshing of the toothed volumes of a pair of screw rotors, creating changes in the volume of the basic unit space formed by the toothed spaces to complete the process of gas intake, compression, and discharge. The internal volume ratio Vi (Vi = Vs / Vd) is an important operating parameter of the screw compressor, where Vs is the rotor intake chamber volume and Vd is the rotor discharge chamber volume. The internal volume ratio Vi can be adjusted by changing the position of the slide valve to regulate the size of the rotor discharge chamber volume.

[0003] Depending on the different operating conditions of the refrigeration system, the system has different external volume ratios Vi. sys Ideally, the internal volume ratio Vi of the compressor should be similar to the external volume ratio Vi of the refrigeration system. sys The compressor is matched so that the pressure in the compressor's rotor discharge chamber is equal to the discharge pressure of the refrigeration system, thereby avoiding the extra power consumption caused by over-compression or under-compression and ensuring that the compressor operates at its optimal efficiency. Summary of the Invention

[0004] At least one objective of this application in a first aspect is to provide a compressor control system in a refrigeration system, the refrigeration system including a compressor and an economizer, wherein the compressor includes a slide valve, the economizer having an inlet pipe, a gas outlet pipe, and a liquid outlet pipe, the compressor control system including: an inlet pipe sensor for detecting pressure and temperature parameters of the inlet pipe; a gas outlet pipe sensor for detecting pressure and temperature parameters of the gas outlet pipe; a liquid outlet pipe sensor for detecting pressure and temperature parameters of the liquid outlet pipe; and a control device configured to: receive pressure and temperature parameters of the inlet pipe, the gas outlet pipe, and the liquid outlet pipe; and control the movement of the slide valve based on the pressure and temperature parameters, thereby adjusting the position of the slide valve.

[0005] According to the first aspect above, the inlet pipe sensor includes an inlet pipe pressure sensor and an inlet pipe temperature sensor, the inlet pipe pressure sensor and the inlet pipe temperature sensor being configured to detect the pressure parameter and temperature parameter of the inlet pipe, respectively; the gas outlet pipe sensor includes a gas outlet pipe pressure sensor and a gas outlet pipe temperature sensor, the gas outlet pipe pressure sensor and the gas outlet pipe temperature sensor being configured to detect the pressure parameter and temperature parameter of the gas outlet pipe, respectively; the liquid outlet pipe sensor includes a liquid outlet pipe pressure sensor and a liquid outlet pipe temperature sensor, the liquid outlet pipe pressure sensor and the liquid outlet pipe temperature sensor being configured to detect the pressure parameter and temperature parameter of the liquid outlet pipe, respectively.

[0006] According to the first aspect above, the refrigeration system has an external volume ratio Vi sys The compressor has an internal volume ratio Vi, the slide valve is used to adjust the internal volume ratio Vi of the compressor, and the control device is configured to: receive various pressure parameters and various temperature parameters of the inlet pipe, the gas outlet pipe, and the liquid outlet pipe; calculate the calibration coefficient A of the compressor based on the various pressure parameters and various temperature parameters; and adjust the external volume ratio Vi according to the external volume ratio Vi. sys The internal volume ratio Vi of the compressor is calculated using the calibration coefficient A; the position of the slide valve is adjusted according to the internal volume ratio Vi.

[0007] According to the first aspect above, the compressor further includes a drive device communicatively connected to the control device; the slide valve has a first position corresponding to the minimum internal volume ratio of the compressor and a second position corresponding to the maximum internal volume ratio of the compressor; wherein the drive device is configured to drive the slide valve to move between the first position and the second position to adjust the internal volume ratio of the compressor.

[0008] According to the first aspect above, the compressor has an intake pipe and an exhaust pipe; the compressor control system further includes: an intake pressure sensor configured to detect pressure parameters of the intake pipe; and an exhaust pressure sensor configured to detect pressure parameters of the exhaust pipe; wherein the control device is configured to calculate the external volume ratio Vi based on the pressure parameters of the intake pipe and the pressure parameters of the exhaust pipe. sys .

[0009] According to the first aspect above, the calculation of the calibration coefficient A of the compressor based on various pressure parameters and various temperature parameters includes: calculating the enthalpy H1 of the inlet refrigerant in the inlet pipe based on the pressure and temperature parameters of the inlet pipe; calculating the enthalpy H2 of the liquid refrigerant in the liquid outlet pipe based on the pressure and temperature parameters of the liquid outlet pipe; calculating the enthalpy H3 of the gaseous refrigerant in the gas outlet pipe based on the pressure and temperature parameters of the gas outlet pipe; and obtaining the calibration coefficient A according to the following formula: A = (H1 - H2) / (H3 - H1).

[0010] According to the first aspect above, the control device is configured to calculate the internal volume ratio Vi according to the following formula: Vi = Vi sys / (1+A).

[0011] At least one objective of the second aspect of this application is to provide a control method for a compressor control system in a refrigeration system, the refrigeration system including a compressor and an economizer, wherein the compressor includes a slide valve, and the economizer has an inlet pipe, a gas outlet pipe, and a liquid outlet pipe, the control method comprising the steps of: receiving pressure parameters and temperature parameters of the inlet pipe, the gas outlet pipe, and the liquid outlet pipe; and controlling the movement of the slide valve based on the respective pressure parameters and the respective temperatures, thereby adjusting the position of the slide valve.

[0012] According to the second aspect above, the refrigeration system has an external volume ratio Vi sys The compressor has an internal volume ratio Vi, and the slide valve is used to control the internal volume ratio Vi of the compressor; controlling the movement of the slide valve based on various pressure parameters and various temperatures includes: calculating the calibration coefficient A of the compressor based on various pressure parameters and various temperature parameters; and adjusting the external volume ratio Vi according to the external volume ratio Vi. sys The internal volume ratio Vi of the compressor is calculated using the calibration coefficient A; the position of the slide valve is adjusted according to the internal volume ratio Vi.

[0013] According to the second aspect above, the compressor has an intake pipe and an exhaust pipe, wherein the external volume ratio Vi is calculated based on the pressure parameters of the intake pipe and the pressure parameters of the exhaust pipe. sys .

[0014] According to the second aspect above, the enthalpy H1 of the inlet refrigerant in the inlet pipe is calculated based on the pressure and temperature parameters of the inlet pipe; the enthalpy H2 of the liquid refrigerant in the liquid outlet pipe is calculated based on the pressure and temperature parameters of the liquid outlet pipe; the enthalpy H3 of the gas refrigerant in the gas outlet pipe is calculated based on the pressure and temperature parameters of the gas outlet pipe; and the calibration coefficient A is calculated according to the following formula: A = (H1 - H2) / (H3 - H1).

[0015] Based on the second aspect above, the content product ratio Vi is calculated using the following formula: Vi = Vi sys / (1+A).

[0016] Other features, advantages, and embodiments of this application may be set forth or become apparent upon consideration of the following detailed description, accompanying drawings, and claims. Furthermore, it should be understood that the above description and the following detailed description are exemplary and intended to provide further explanation, without limiting the scope of the claimed application. However, the detailed description and specific examples merely indicate preferred embodiments of this application. Various changes and modifications within the spirit and scope of this application will become apparent to those skilled in the art through these detailed descriptions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a refrigeration system according to an embodiment of this application;

[0018] Figure 2A This is a schematic diagram of the compressor when the slide valve is in the first position.

[0019] Figure 2B This is a schematic diagram of the compressor when the slide valve is in the second position.

[0020] Figures 3A-3C This is a block diagram of the control device.

[0021] Figures 4A-4C This is a flowchart of the control method. Detailed Implementation

[0022] Various specific embodiments of this application will now be described with reference to the accompanying drawings, which form part of this specification. It should be understood that although directional terms such as "front," "rear," "upper," "lower," "left," "right," "top," and "bottom" are used in this application to describe various exemplary structural parts and elements, their use is merely for illustrative purposes and is based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in this application can be arranged in different orientations, these directional terms are for illustrative purposes only and should not be considered as limiting.

[0023] Figure 1 A schematic diagram of the refrigeration system 110 according to this application is shown. Figure 1 As shown, the refrigeration system 110 includes a compressor 100, a condenser 101, an economizer 103, a throttling device 104, and an evaporator 102 that are in sequential fluid communication.

[0024] The high-temperature, high-pressure gaseous refrigerant discharged from the exhaust port 107 of the compressor 100 enters the condenser 101, releases heat to condense into liquid refrigerant, and then enters the economizer 103. In the economizer 103, a portion of the liquid refrigerant exchanges heat with another portion of the liquid refrigerant. One portion of the liquid refrigerant evaporates into gaseous refrigerant and returns to the compressor 100, while the other portion of the liquid refrigerant is cooled into subcooled liquid refrigerant and enters the throttling device 104. In the throttling device 104, it is throttled into low-pressure two-phase refrigerant and then enters the evaporator 102. In the evaporator 102, it absorbs heat to evaporate into gaseous refrigerant and finally returns to the compressor 100 through the suction port 106, completing the refrigerant circulation. Although not shown in the figure, those skilled in the art will understand that the refrigerant used for evaporation also needs to undergo throttling.

[0025] The refrigeration system 110 also includes a compressor control system, which includes a control device 120. The compressor control system controls the internal volume ratio of the compressor, ensuring that the compressor's rotor discharge chamber pressure (i.e., internal pressure) matches the refrigeration system's discharge pressure (i.e., external pressure), thereby preventing over-compression or under-compression. By adjusting the compressor's internal volume ratio in real time according to the operating conditions of the refrigeration system 110, the operating efficiency of the refrigeration system can be improved, and energy consumption reduced.

[0026] In the refrigeration system 110 of this application, which includes an economizer 103, the change in the density of the refrigerant gas in the compressor's exhaust chamber is used to represent the change in the compressor's internal volume ratio Vi. Furthermore, a calibration coefficient A is obtained using the conservation of heat transfer energy in the economizer, thereby calibrating the internal volume ratio Vi to an equivalent internal volume ratio Vi*. Then, the control device 120 sets the equivalent internal volume ratio Vi* to be equal to the external volume ratio Vi of the refrigeration system. sysThen, based on the external volume ratio Vi of the refrigeration system 110 sys The internal volume ratio Vi of compressor 100 is derived from the calibration coefficient A, and finally the compressor slide valve 232 is adjusted according to the internal volume ratio Vi (see...). Figure 2A and Figure 2B The position shown allows the rotor exhaust chamber pressure of compressor 100 to match the exhaust pressure of refrigeration system 110, thereby avoiding over-compression or under-compression.

[0027] Specifically, the compressor control system includes a suction pressure sensor 127 and a discharge pressure sensor 128. The suction pressure sensor 127 is installed on the suction pipe 111 between the suction port 106 of the compressor 100 and the evaporator 102, and the discharge pressure sensor 128 is installed on the discharge pipe 112 between the discharge port 107 of the compressor 100 and the condenser 101. The suction pressure sensor 127 and the discharge pressure sensor 128 are communicatively connected to the control device 120 and are used to detect the suction pressure Ps in the suction pipe 111 and the discharge pressure Pd in ​​the discharge pipe 112, respectively, and obtain their respective pressure parameters. The external volume ratio Vi of the refrigeration system can be calculated using the suction pressure Ps and the discharge pressure Pd. sys .

[0028] Economizer 103 is fluidly connected to condenser 101 via inlet pipe 113, fluidly connected to compressor 100's gas supply port 108 via gas outlet pipe 114, and fluidly connected to throttling device 104 via liquid outlet pipe 115. The compressor control system also includes inlet pipe sensors, gas outlet pipe sensors, and liquid outlet pipe sensors. These sensors are also communicatively connected to control device 120. The inlet pipe sensor is installed on inlet pipe 113 to detect the pressure and temperature in inlet pipe 113 and obtain their respective pressure and temperature parameters. In this embodiment, the inlet pipe sensor includes inlet pipe pressure sensor 122 and inlet pipe temperature sensor 121. The gas outlet pipe sensor is installed on gas outlet pipe 114 to detect the pressure and temperature in gas outlet pipe 114 and obtain their respective pressure and temperature parameters. In this embodiment, the gas outlet pipe sensor includes gas outlet pipe pressure sensor 124 and gas outlet pipe temperature sensor 123. The liquid outlet pipe sensor is installed on liquid outlet pipe 115 to detect the pressure and temperature in liquid outlet pipe 115 and obtain their respective pressure and temperature parameters. In this embodiment, the liquid outlet pipe sensor includes a liquid outlet pipe pressure sensor 126 and a liquid outlet pipe temperature sensor 125.

[0029] By detecting the pressure and temperature in each pipe of the economizer 103, the enthalpy H1 of the inlet refrigerant entering the economizer 103 from the inlet pipe 113, the enthalpy H2 of the liquid refrigerant flowing out of the economizer 103 from the liquid outlet pipe 115, and the enthalpy H3 of the gaseous refrigerant flowing out of the economizer 103 from the gas outlet pipe 114 can be obtained. Based on the enthalpy H1 of the inlet refrigerant, the enthalpy H2 of the liquid refrigerant, and the enthalpy H3 of the gaseous refrigerant, a calibration coefficient A can be calculated. This calibration coefficient A reflects the change in the compressor's exhaust chamber density caused by the economizer's gas injection.

[0030] Based on the external volume ratio Vi of the refrigeration system sys The internal volume ratio of the compressor, Vi, is calculated by reverse calculation using the compressor's calibration coefficient A. sys ×(1+A).

[0031] Figure 2A and Figure 2B A schematic diagram of the compressor structure is shown, in which... Figure 2A This shows the state of the slide valve when it is in the first position. Figure 2B This shows the spool valve in its second position. (Example:) Figure 2A and Figure 2B As shown, the compressor 100 includes an intake chamber 236, an exhaust chamber 237, and a compression chamber 231. The intake chamber 236 is fluidly connected to the intake pipe 111 via an intake port 106, and the exhaust chamber 237 is fluidly connected to the exhaust pipe 112 via an exhaust port 107. The compression chamber 231 is formed by the tooth slots of a pair of screw rotors, and the compression chamber 231 is fluidly connected to the intake chamber 236 and the exhaust chamber 237. A make-up air port 108 is fluidly connected to the compression chamber 231. Thus, the refrigerant in the intake pipe 111 can enter the intake chamber 236 through the intake port 106 and then enter the compression chamber 231 for compression. The refrigerant in the gas outlet pipe 114 can also flow into the compression chamber 231 through the make-up air port 108 for compression. After both parts of the refrigerant are compressed, they enter the exhaust chamber 237 together and are finally discharged into the exhaust pipe 112 through the exhaust port 107, completing the compression process of the compressor 100.

[0032] The compressor 100 also includes a slide valve 232 and a drive unit 233. The drive unit 233 is mechanically connected to the slide valve 232 to drive the slide valve 232 to move. The drive unit 233 is also communicatively connected to the control unit 120. The slide valve 232 has a first position corresponding to the minimum internal volume ratio of the compressor 100 and a second position corresponding to the maximum internal volume ratio of the compressor 100. Specifically, when the slide valve 232 moves to such a position... Figure 2A When the leftmost position (i.e., the first position) is shown, the exhaust chamber 237 has the largest exhaust chamber volume, and therefore the smallest internal volume ratio. When the slide valve 232 moves to... Figure 2BIn the rightmost position shown (i.e., the second position), the exhaust chamber 237 has the smallest exhaust chamber volume, and therefore the largest internal volume ratio. The drive unit 233 controls the movement of the slide valve 232 between the first and second positions to adjust the volume of the exhaust chamber 237, thereby adjusting the internal volume ratio Vi of the compressor 100. Those skilled in the art will understand that the drive unit 233 may include a position sensor (not shown) for detecting the position of the slide valve to control the movement position of the slide valve 232.

[0033] Compared to a refrigeration system excluding the economizer, even if the system operating conditions and the position of the slide valve 232 remain unchanged, the actual internal volume ratio of the compressor 100 will change due to the refrigerant entering the compression chamber 231 from the gas filler port 108. Therefore, if the external volume ratio Vi of the refrigeration system 110 is... sys Adjusting the position of the slide valve 232 will change the ratio of the actual internal volume Vi of the compressor 100 to the ratio of the external volume Vi of the refrigeration system 110. sys Inconsistent.

[0034] In the compressor control system of this application, the calibrated equivalent internal volume ratio Vi* is set to be equal to the external volume ratio Vi. sys Then, based on the compressor's calibration coefficient A, the internal volume ratio Vi of the compressor is calculated, and the position of the slide valve 232 is adjusted according to the internal volume ratio Vi, so that the actual internal volume ratio of the compressor 100 is equal to the external volume ratio Vi of the refrigeration system 110. sys Consistent.

[0035] More specifically, the external volume of the refrigeration system is greater than Vi. sys = (Pd / Ps)^(1 / k), where k is the adiabatic index of the refrigerant at the compressor suction port.

[0036] The equivalent internal volume ratio of compressor 100 is Vi*=ρd* / ρs, where ρd* represents the discharge density of the compressor and ρs represents the intake density of the compressor.

[0037] And ρs = m2 / Vs, ρd* = (m2 + m3) / Vd. Here, m2 represents the mass of liquid refrigerant flowing out of liquid outlet pipe 115, i.e., the compressor's suction volume, and m3 represents the mass of gaseous refrigerant flowing out of economizer gas outlet pipe 114, i.e., the economizer's make-up gas volume. Vs represents the suction chamber volume, and Vd represents the discharge chamber volume. Thus, the calibration formula for the compressor's internal volume ratio Vi is obtained, that is, the relationship between the compressor's equivalent internal volume ratio Vi and the internal volume ratio Vi is: Vi* = [(m2 + m3) / m2] × Vi.

[0038] Control device 120 sets the equivalent internal volume ratio Vi* of compressor 100 and the external volume ratio Vi of system. sysConsistent. That is to say, Vi sys =Vi*=[(m2+m3) / m2]×Vi. Therefore, we can deduce that Vi=Vi sys ×[m2 / (m2+m3)].

[0039] Furthermore, since the refrigerant entering the economizer 103 from the inlet pipe 113 undergoes heat exchange inside the economizer 103, according to the energy conservation of the economizer, the refrigerant satisfies m3×(H3-H1)=m2×(H1–H2). Here, m1 represents the total mass of the inlet refrigerant entering the economizer 103 from the inlet pipe 113.

[0040] Therefore, Vi sys =[(m2+m3) / m2]×Vi=(1+m3 / m2)×Vi=(1+A)×Vi. The compressor calibration coefficient A=(H1-H2) / (H3-H1).

[0041] Therefore, it is possible to determine the external volume ratio Vi of the refrigeration system. sys The internal volume ratio of the compressor, Vi = Vi, is calculated using the compressor's calibration coefficient A. sys / (1+A).

[0042] Figures 3A-3C A structural block diagram of the control device 120 is shown. Figure 3A As shown, the control device 120 includes a bus 341, a processor 342, an input interface 343, an output interface 344, and a memory 345 containing a control program 346. Each component of the control device 120, including the processor 342, input interface 343, output interface 344, and memory 345, is communicatively connected to the bus 341, enabling the processor 342 to control the operation of the input interface 343, output interface 344, and memory 345. Specifically, the memory 345 stores programs, instructions, and data, while the processor 342 reads programs, instructions, and data from the memory 345 and can write data to the memory 345. By executing the programs and instructions read from the memory 345, the processor 342 controls the operation of the input interface 343 and output interface 344.

[0043] like Figures 3A-3CAs shown, input interface 343 is communicatively connected via connection 347 to inlet pipe temperature sensor 121 and inlet pipe pressure sensor 122, gas outlet pipe temperature sensor 123 and gas outlet pipe pressure sensor 124, liquid outlet pipe temperature sensor 125 and liquid outlet pipe pressure sensor 126, and suction pressure sensor 127 and exhaust pressure sensor 128 to receive pressure and / or temperature parameters from each sensor and store these pressure and / or temperature parameters in memory 345. Output interface 344 is communicatively connected via connection 348 to drive unit 233 of compressor 100. By executing program 346 in memory 345, control unit 120 controls the position of slide valve 232 by controlling drive unit 233.

[0044] Figures 4A-4C This is a flowchart of the control method for a compressor control system.

[0045] At step 450, the program begins.

[0046] At step 451, the control device 120 executes step 452 to obtain the external volume ratio Vi of the refrigeration system. sys And perform step 453 to obtain the compressor calibration coefficient A.

[0047] At step 454, the control device 120 determines the external volume ratio Vi based on the obtained data. sys The internal volume ratio Vi of the compressor is calculated using the calibration coefficient A.

[0048] At step 455, the control device 120 controls the drive device 233 to move according to the internal volume ratio Vi, so as to adjust the position of the slide valve 232.

[0049] At step 456, the control device 120 determines whether the refrigeration system 110 has stopped operating. If the refrigeration system 110 has stopped operating, step 457 is executed. If the refrigeration system 110 has not stopped operating, the process returns to step 451.

[0050] The program ends at step 457.

[0051] Step 452 includes steps 461 and 462. In step 461, the control device 120 receives pressure parameters from the intake pressure sensor 127 and the exhaust pressure sensor 128.

[0052] In step 462, the control device 120 calculates the external volume ratio Vi. sys .

[0053] Step 453 includes steps 464, 465, and 466. In step 464, the control device 120 receives pressure and temperature parameters from the inlet pipe temperature sensor 121 and the inlet pipe pressure sensor 122, the gas outlet pipe temperature sensor 123 and the gas outlet pipe pressure sensor 124, and the liquid outlet pipe temperature sensor 125 and the liquid outlet pipe pressure sensor 126.

[0054] In step 465, the control device 120 calculates the enthalpy H1 of the refrigerant in the inlet pipe 113, the enthalpy H2 of the refrigerant in the liquid outlet pipe 115, and the enthalpy H3 of the refrigerant in the gas outlet pipe 114.

[0055] In step 466, the control device 120 calculates the calibration coefficient A.

[0056] When the refrigeration system does not include an economizer, the compressor's rotor discharge chamber pressure can be made consistent with the refrigeration system's discharge pressure by matching the compressor's internal volume ratio with the refrigeration system's external volume ratio. However, when the refrigeration system includes an economizer, the refrigerant discharged from the discharge port 107 includes refrigerant drawn in from both the suction port 106 and the make-up port 108. Therefore, compared to a refrigeration system without an economizer, when the compressor's slide valve is in the same position, under the same system operating conditions and suction pressure, the volume of refrigerant discharged from the discharge port 107 remains unchanged, while its mass and density increase. This causes the compressor's rotor discharge chamber pressure to exceed the refrigeration system's discharge pressure, resulting in undesirable overcompression of the refrigeration system.

[0057] If the external volume ratio Vi of the refrigeration system is calibrated by replacing the gas outlet pressure of the economizer with the suction pressure Ps of the refrigeration system. sys Then, the compressor slider position is set so that the internal volume ratio Vi of the compressor is equal to the calibrated external volume ratio Vi. sys Consistent. This calibration method, which uses pressure substitution to reflect the impact of the economizer, is greatly affected by pipeline design and pressure drop, resulting in inaccurate calibration results.

[0058] In this application, the internal volume ratio Vi of the compressor is calibrated to the external volume ratio Vi of the system by measuring the changes in the mass and density of the refrigerant discharged from the compressor's discharge port, as well as the operating conditions of the economizer. sys With an equal equivalent internal volume ratio Vi*, the calibration results are more accurate and reliable. The calibration method in this application is only related to the enthalpy values ​​at each connection pipe of the economizer, and is independent of pipe design and pressure drop, thus avoiding the influence of pressure drop. Based on the calibration results, the compressor control system of this application can, during the operation of the refrigeration system, adjust the system's external volume ratio Vi*. sysBy adjusting the compressor's internal volume ratio Vi in real time, the operating efficiency of the refrigeration system is improved, and energy consumption is reduced.

[0059] Furthermore, in this application, when calculating the calibration coefficient A, it is not necessary to directly detect the mass or pressure. Instead, the calibration coefficient A is obtained by converting the mass ratio into an enthalpy value, making the calculation method simpler and more accurate.

[0060] Furthermore, since the compressor control system of this application only needs to calculate the enthalpy values ​​at the inlet and each outlet of the economizer, it is also suitable for controlling compressors with multiple gas inlets.

[0061] Although this disclosure has been described in conjunction with examples of the embodiments outlined above, various alternatives, modifications, variations, improvements, and / or substantially equivalents, whether known or now or soon to be foreseen, will likely be apparent to those skilled in the art. Therefore, the examples of embodiments of this disclosure set forth above are intended to be illustrative rather than restrictive. Various changes can be made without departing from the spirit or scope of this disclosure. Therefore, this disclosure is intended to include all known or previously developed alternatives, modifications, variations, improvements, and / or substantially equivalents. The technical effects and problems described in this specification are exemplary rather than restrictive. It should be noted that the embodiments described in this specification may have other technical effects and may solve other technical problems.

Claims

1. A compressor control system in a refrigeration system (110), the refrigeration system (110) comprising a compressor (100) and an economizer (103), wherein the compressor (100) includes a slide valve (232), the economizer (103) has an inlet pipe (113), a gas outlet pipe (114) and a liquid outlet pipe (115), and the refrigeration system (110) has an external volume ratio Vi sys The compressor (100) has an internal volume ratio Vi, and the slide valve (232) is used to adjust the internal volume ratio Vi of the compressor (100), characterized in that... The compressor control system includes: Inlet pipe sensors (121, 122) are used to detect pressure and temperature parameters in the inlet pipe (113); Gas outlet pipe sensors (123, 124) are used to detect pressure and temperature parameters in the gas outlet pipe (114); Liquid outlet pipe sensors (125, 126) are used to detect pressure and temperature parameters in the liquid outlet pipe (115); and Control device (120), the control device (120) being configured to: Receive pressure and temperature parameters from the inlet pipe (113), the gas outlet pipe (114), and the liquid outlet pipe (115); The calibration coefficient A of the compressor (100) is calculated based on each pressure parameter and each temperature parameter. According to the external volume ratio Vi sys The internal volume ratio Vi of the compressor (100) is calculated using the calibration coefficient A; The position of the slide valve (232) is adjusted by controlling the movement of the slide valve (232) according to the volume ratio Vi.

2. The compressor control system in the refrigeration system according to claim 1, characterized in that: The inlet pipe sensors (121, 122) include an inlet pipe pressure sensor (122) and an inlet pipe temperature sensor (121), which are configured to detect pressure and temperature parameters in the inlet pipe (113), respectively. The gas outlet pipe sensor (123, 124) includes a gas outlet pipe pressure sensor (124) and a gas outlet pipe temperature sensor (123), which are configured to detect pressure and temperature parameters in the gas outlet pipe (114), respectively. The liquid outlet pipe sensor (125, 126) includes a liquid outlet pipe pressure sensor (126) and a liquid outlet pipe temperature sensor (125), which are configured to detect pressure and temperature parameters in the liquid outlet pipe (115), respectively.

3. The compressor control system in the refrigeration system according to claim 1, characterized in that: The compressor (100) further includes a drive unit (233), which is communicatively connected to the control unit (120); The slide valve (232) has a first position corresponding to the minimum internal volume ratio of the compressor (100) and a second position corresponding to the maximum internal volume ratio of the compressor (100); The drive unit (233) is configured to drive the slide valve (232) to move between the first position and the second position to adjust the internal volume ratio of the compressor (100).

4. The compressor control system in the refrigeration system according to claim 1, characterized in that: The compressor (100) has an intake pipe (111) and an exhaust pipe (112); The compressor control system also includes: An inhalation pressure sensor (127) is configured to detect pressure parameters in the inhalation conduit (111); An exhaust pressure sensor (128) is configured to detect pressure parameters in the exhaust pipe (112); The control device (120) is configured to calculate the external volume ratio Vi based on the pressure parameters in the intake pipe (111) and the pressure parameters in the exhaust pipe (112). sys .

5. The compressor control system in the refrigeration system according to claim 4, characterized in that: The calculation of the calibration coefficient A of the compressor (100) based on various pressure and temperature parameters includes: The enthalpy H1 of the inlet refrigerant in the inlet pipe (113) is calculated based on the pressure and temperature parameters in the inlet pipe (113); The enthalpy H2 of the liquid refrigerant in the liquid outlet pipe (115) is calculated based on the pressure and temperature parameters in the liquid outlet pipe (115); The enthalpy H3 of the gas refrigerant in the gas outlet pipe (114) is calculated based on the pressure and temperature parameters in the gas outlet pipe (114); The calibration coefficient A is obtained using the following formula: A = (H1-H2) / (H3-H1).

6. The compressor control system in the refrigeration system according to claim 5, characterized in that: The control device (120) is configured to calculate the content area ratio Vi according to the following formula: You=You sys / (1+A).

7. A control method for a compressor control system in a refrigeration system, the refrigeration system (110) comprising a compressor (100) and an economizer (103), wherein the compressor (100) includes a slide valve (232), the economizer (103) has an inlet pipe (113), a gas outlet pipe (114), and a liquid outlet pipe (115), and the refrigeration system (110) has an external volume ratio Vi sys The compressor (100) has an internal volume ratio Vi, and the slide valve (232) is used to control the internal volume ratio Vi of the compressor (100), characterized in that... The control method includes the following steps: Receive pressure and temperature parameters from the inlet pipe (113), the gas outlet pipe (114), and the liquid outlet pipe (115); The calibration coefficient A of the compressor (100) is calculated based on each pressure parameter and each temperature parameter. According to the external volume ratio Vi sys The internal volume ratio Vi of the compressor (100) is calculated using the calibration coefficient A; The position of the slide valve (232) is adjusted by controlling the movement of the slide valve (232) according to the volume ratio Vi.

8. The control method for the compressor control system according to claim 7, characterized in that: The compressor (100) has an intake pipe (111) and an exhaust pipe (112), wherein the external volume ratio Vi is calculated based on the pressure parameters in the intake pipe (111) and the pressure parameters in the exhaust pipe (112). sys .

9. The control method for the compressor control system according to claim 7, characterized in that: The enthalpy H1 of the inlet refrigerant in the inlet pipe (113) is calculated based on the pressure and temperature parameters in the inlet pipe (113); The enthalpy H2 of the liquid refrigerant in the liquid outlet pipe (115) is calculated based on the pressure and temperature parameters in the liquid outlet pipe (115); The enthalpy H3 of the gas refrigerant in the gas outlet pipe (114) is calculated based on the pressure and temperature parameters in the gas outlet pipe (114); The calibration coefficient A is calculated using the following formula: A = (H1 - H2) / (H3 - H1).

10. The control method for the compressor control system according to claim 7, characterized in that: The content product ratio Vi is calculated using the following formula: You=You sys / (1+A).

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