Air conditioning unit electronic expansion valve adjustment control method and system and air conditioning unit

Abstract

The invention discloses an air conditioning unit electronic expansion valve adjustment control method and system and an air conditioning unit, and the method comprises the steps that state parameters of a compressor in the air conditioning unit are collected, and the state parameters comprise a first state parameter related to temperature control and a plurality of second state parameters related to safety protection control of the compressor; calculating a first adjustment value for adjusting the valve opening of the electronic expansion valve at present based on the first state parameter and a corresponding first set value; calculating a second adjustment value for adjusting the valve opening of the electronic expansion valve based on the second state parameter and a corresponding second set value; and adjusting the valve opening degree of the electronic expansion valve based on a comprehensive calculation value of the first adjustment value and the second adjustment value. Based on the method, the electronic expansion valve can be efficiently, accurately and stably controlled, and the diversity of various customer working conditions is met; and under special working conditions, the safety of the compressor and other core components can be guaranteed, and safe and stable operation of the unit can be guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning control, and in particular to an adjustment control method and system for an electronic expansion valve of an air conditioning unit, and an air conditioning unit. Background Art

[0002] In the design and application of air conditioning systems, the adjustment and control of electronic expansion valves is crucial to the performance and safety of the unit. Traditional chillers usually use proportional integral differential (PID) algorithms to control electronic expansion valves. However, PID control has many limitations when dealing with complex operating conditions.

[0003] When the unit's operating conditions exceed the normal operating range of the compressor, the electronic expansion valve needs to perform a protective action. However, the traditional control method usually forces the PID algorithm to switch to program manual control, that is, to achieve this by periodically adjusting the opening of the electronic expansion valve. This method of frequently switching between PID automatic control and manual on / off valves can temporarily ensure the safety range of certain parameters, but it is easy to cause unstable operation of the unit. This instability not only affects the performance of the air conditioning system, but may also cause noise and vibration problems, thereby affecting the user's comfort and long-term safety.

[0004] A more complicated problem is that when the unit needs to deal with multiple operating conditions at the same time, such as some parameters need valve opening protection, while other parameters need valve closing protection, the traditional control method only executes one of the protection measures by priority. This one-sided and single protection measure cannot comprehensively judge the overall operating status of the unit, which may cause other parameters to deteriorate and aggravate the instability of unit operation.

[0005] In addition, as the demand for chillers in different industries continues to develop, users have higher and higher requirements for the diversity of unit operating conditions. The traditional approach of only being able to meet specific customer needs by customizing protection parameters has become inadequate. Therefore, the existing electronic expansion valve control method is difficult to adapt to the diverse needs of the market. Summary of the invention The purpose of the present invention is to solve the above-mentioned technical problems and to provide an electronic expansion valve adjustment control method, system and air-conditioning unit for an air-conditioning unit, which can comprehensively judge the valve opening of the electronic expansion valve based on various state parameters of the compressor so that the electronic expansion valve can adapt to a variety of different working conditions.

[0006] In order to achieve the above object, the present invention provides an adjustment and control method of an electronic expansion valve of an air conditioning unit, which comprises: Collecting state parameters of a compressor in an air-conditioning unit, the state parameters including a first state parameter related to temperature control and a plurality of second state parameters related to safety protection control of the compressor; Calculating a first adjustment value for adjusting the valve opening of the electronic expansion valve based on the first state parameter and a preset first setting value corresponding to the first state parameter; Calculating a second adjustment value for adjusting the valve opening of the electronic expansion valve based on the second state parameter and a preset second setting value corresponding to the second state parameter; The first adjustment value and the second adjustment value reflect the direction and the number of steps for adjusting the valve opening of the electronic expansion valve; The valve opening of the electronic expansion valve is adjusted based on a comprehensive calculation value of the first adjustment value and the second adjustment value.

[0007] Preferably, the first state parameter includes suction superheat, and the first adjustment value A is calculated based on the following formula: ; in, is the current suction superheat of the compressor, is the suction superheat degree related to the target temperature. 1 is the automatic control adjustment coefficient.

[0008] Preferably, the second state parameter includes the low pressure value of the low pressure side of the compressor, and the second adjustment value B1 related to the low pressure too high protection is calculated based on the following formula, and the second adjustment value B2 related to the low pressure too low protection is calculated: ; ; When B1>0, adjust B1 to 0; when B2<0, adjust B2 to 0; in, is a preset temperature value related to the low pressure over-high protection value of the compressor, is a preset temperature value related to the low pressure protection value of the compressor, is the evaporation temperature obtained by converting the currently collected pressure on the low-pressure side of the compressor, 2 is the low voltage over-high protection adjustment coefficient, It is the low voltage protection adjustment coefficient.

[0009] Preferably, the second state parameter includes the exhaust gas superheat of the compressor, and the second adjustment value B3 is calculated based on the following formula: ; When B3>0, adjust B3 to 0; in, is the current exhaust gas superheat of the compressor, is the exhaust superheat protection value of the compressor set, It is the exhaust superheat protection adjustment coefficient.

[0010] Preferably, the second state parameter includes the pressure difference between the high-pressure side and the low-pressure side of the compressor, and the second adjustment value B4 is calculated based on the following formula: ; When B4>0, adjust B4 to 0; in, is the current pressure difference between the high-pressure side and the low-pressure side of the compressor, is the protection value of the pressure difference between the high-pressure side and the low-pressure side of the compressor, It is the pressure difference protection adjustment coefficient.

[0011] Preferably, the state parameter further includes a third state parameter related to the load of the air-conditioning unit, and a third adjustment value for adjusting the valve opening of the electronic expansion valve is calculated based on the third state parameter and a preset third setting value corresponding to the third state setting parameter; The third adjustment value C is calculated based on the following formula: ; in, is the current difference between the compressor in the current acquisition cycle and the previous acquisition cycle, is the load change valve opening adjustment coefficient.

[0012] Preferably, before the compressor is started, the electronic expansion valve operates at a basic valve opening, and the basic valve opening D is dynamically adjusted according to the following formula: ; in, is the preset valve opening corresponding to the reference ambient temperature, is the current ambient temperature, is the reference ambient temperature; is the pre-opening adjustment coefficient.

[0013] The present invention also provides an air conditioning unit, comprising a controller, a compressor and an electronic expansion valve connected to the compressor, wherein the controller controls the valve opening of the electronic expansion valve based on the air conditioning unit electronic expansion valve adjustment control method as described above.

[0014] The present invention also provides an air-conditioning unit electronic expansion valve adjustment control system, which comprises: one or more processors; Memory; and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the programs include instructions for executing the air conditioning unit electronic expansion valve adjustment control method as described above.

[0015] The present invention also provides a computer-readable storage medium, which includes a computer program, and the computer program can be executed by a processor to implement the air-conditioning unit electronic expansion valve adjustment control method as described above.

[0016] Compared with the prior art, the electronic expansion valve adjustment control method for air-conditioning units provided by the above technical solution of the present invention collects the state parameters of the compressor in the air-conditioning unit under various states, and respectively calculates the valve opening of the electronic expansion valve under each state parameter, and then comprehensively calculates the adjustment value of the total valve opening. Therefore, this control method can improve the response speed and control accuracy of the compressor. This precise control ensures that the compressor can maintain the best operating state under various complex working conditions. In addition, the method particularly considers the safety under special working conditions, that is, under special working conditions, the method can automatically adjust the opening of the electronic expansion valve to protect the core components such as the compressor to prevent overload or damage. Furthermore, by setting the adjustment valve opening of the electronic expansion valve to a comprehensive calculation value, the control process is simplified. There is no need for human judgment and setting of the entry and exit conditions of various states, which reduces the complexity of operation and human errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of the electronic expansion valve adjustment control method for an air-conditioning unit in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0019] This embodiment discloses an electronic expansion valve adjustment control method for an air-conditioning unit, which is used to automatically adjust the valve opening of an electronic expansion valve connected to a compressor in the air-conditioning unit, thereby ensuring the working performance of the compressor and the safety performance of the compressor. Figure 1 , the control method comprises the following steps: S1: collecting state parameters of a compressor in an air-conditioning unit, wherein the state parameters include a first state parameter related to temperature control and a plurality of second state parameters related to safety protection control of the compressor.

[0020] S20: Calculating a first adjustment value for adjusting the valve opening of the electronic expansion valve based on the first state parameter and a preset first setting value corresponding to the first state parameter.

[0021] S21: Calculating a second adjustment value for adjusting the valve opening of the electronic expansion valve based on the second state parameter and a preset second setting value corresponding to the second state parameter.

[0022] The first adjustment value and the second adjustment value reflect the direction and the number of steps for adjusting the valve opening of the electronic expansion valve.

[0023] S3: adjusting the valve opening of the electronic expansion valve based on a comprehensive calculation value of the first adjustment value and the second adjustment value.

[0024] For example, in the current adjustment cycle, the first adjustment value is 100 and the second adjustment value is -50. The adjustment value of the valve opening is a positive value, which means that the valve opening operation is performed in the current state. The adjustment value of the valve opening is a negative value, which means that the valve closing operation is performed in the current state. In this regard, since the comprehensive calculation value of the first adjustment value and the second adjustment value is 50, in the current adjustment cycle, the electronic expansion valve is opened 50 steps to increase the valve opening of the electronic expansion valve.

[0025] In addition, in the current adjustment cycle, the first adjustment value is -100 and the second adjustment value is 50. The comprehensive calculation value of the first adjustment value and the second adjustment value is -50. In the current adjustment cycle, the electronic expansion valve is closed for 50 steps to reduce the valve opening of the electronic expansion valve.

[0026] Furthermore, in the current adjustment cycle, the first adjustment value is -100 and the second adjustment value is 100. The comprehensive calculation value of the first adjustment value and the second adjustment value is 0. In the current adjustment cycle, the electronic expansion valve is not operated, so that the valve opening of the electronic expansion valve remains in the current state.

[0027] On the other hand, the first state parameter is used to adjust the electronic expansion valve when the compressor is operating normally, so that the temperature of the air outlet of the air conditioning unit is within the set target range. For this purpose, the first state parameter can be suction superheat, evaporator liquid level, condenser liquid level, exhaust superheat, etc. Taking suction superheat as the first state parameter as an example, the first adjustment value A is calculated based on the following formula: ; in, is the current suction superheat of the compressor, is the suction superheat degree related to the target temperature. 1 is the automatic control adjustment coefficient. 1 is 10.

[0028] On the other hand, the second state parameter includes any one or more of a low pressure value of the low pressure side of the compressor, an exhaust gas superheat of the compressor, and a pressure difference between the high pressure side and the low pressure side of the compressor.

[0029] Specifically, when the low pressure value on the low pressure side of the compressor is used as the second state parameter, the electronic expansion valve is adjusted and controlled from two aspects: low pressure too high protection and low pressure too low protection. In this regard, the second adjustment value B1 related to low pressure too high protection is calculated based on the following formula, and the second adjustment value B2 related to low pressure too low protection is calculated: ; ; in, is a preset temperature value related to the low pressure over-high protection value of the compressor, is a preset temperature value related to the low pressure protection value of the compressor, is the evaporation temperature obtained by converting the currently collected pressure on the low-pressure side of the compressor, 2 is the low voltage over-high protection adjustment coefficient, It is the low voltage protection adjustment factor. For example, 2 is 90, is 80.

[0030] During the operation of the air conditioning unit, if the actual evaporation temperature is greater than the low pressure over-protection value and exceeds the normal operating range set by the compressor, the electronic expansion valve needs to be closed to reduce the evaporation temperature to prevent the compressor from operating beyond the operating range. Therefore, B1 must be less than 0. If the calculated B1 is greater than 0, adjust B1 to 0.

[0031] Similarly, during the operation of the air conditioning unit, if the actual evaporation temperature is less than the low pressure protection value, this state exceeds the normal operating range of the compressor setting, and the electronic expansion valve needs to be opened to increase the evaporation temperature to prevent the compressor from operating beyond the operating range. Therefore, B2 must be greater than 0. If the calculated B2 is less than 0, adjust B2 to 0.

[0032] In this embodiment, when the compressor enters the low pressure too low or low pressure too high protection state, the adjustment value of the corresponding electronic expansion valve is calculated, and then comprehensively calculated with the adjustment values ​​calculated based on other state parameters.

[0033] When the exhaust gas superheat of the compressor is used as the second state parameter, the second adjustment value B3 is calculated based on the following formula: ; in, is the current exhaust gas superheat of the compressor, is the exhaust superheat protection value of the compressor set, is the exhaust superheat protection adjustment coefficient. Specifically, is 75.

[0034] In this embodiment, during the operation of the air conditioning unit, if the actual exhaust superheat is less than the exhaust superheat protection value, this state will affect the safety of the compressor, such as liquid return, oil leakage, etc., and the electronic expansion valve needs to be closed and the exhaust superheat is increased to prevent this unsafe state. Therefore, if the calculated B3>0, B3 is adjusted to 0.

[0035] When the pressure difference between the high-pressure side and the low-pressure side of the compressor is used as the second state parameter, the second adjustment value B4 is calculated based on the following formula: ; in, is the current pressure difference between the high-pressure side and the low-pressure side of the compressor, is the protection value of the pressure difference between the high-pressure side and the low-pressure side of the compressor, is the pressure difference protection adjustment coefficient. Specifically, is 80.

[0036] In this embodiment, during the operation of the air conditioning unit, if the actual high and low pressure difference is less than the high and low pressure difference protection value, this state will cause the compressor to return oil in time and damage the compressor. The electronic expansion valve needs to be closed to increase the high and low pressure difference to prevent this unsafe state. Therefore, if the calculated B4>0, B4 is adjusted to 0.

[0037] On the other hand, the state parameters also include a third state parameter related to the load of the air-conditioning unit, and a third adjustment value for adjusting the valve opening of the electronic expansion valve is calculated based on the third state parameter and a preset third setting value corresponding to the third state setting parameter.

[0038] Then, in this embodiment, the third adjustment value C is calculated based on the following formula: ; in, is the current difference between the compressor in the current acquisition cycle and the previous acquisition cycle, is the load change valve opening adjustment coefficient. is 20.

[0039] In summary, when multiple adjustment values ​​are calculated according to various state parameters, for example, when A, B1 or B2, B3, B4, C are calculated, the total number of steps required for adjustment is comprehensively calculated as Z=A+B1(B2)+B3+B4+C.

[0040] On the other hand, the calculated extreme value of the total number of steps Z that need to be adjusted in the current cycle can also be limited to ensure that the adjustment steps can be fully executed within a single cycle, avoiding the adjustment of the next cycle before it is fully executed, resulting in the electronic expansion valve step program calculated value being inconsistent with the actual valve body.

[0041] Specifically, Z satisfies the following constraints: -N≤Z≤N; N = W * P; Wherein, W is the opening calculation period of the electronic expansion valve, and P is the step frequency of the electronic expansion valve. For example, if W is 2S and P is 250 steps / S, then -250≤Z≤250.

[0042] Then, when the total number of steps Z calculated comprehensively is greater than 250 or less than -250, Z is adjusted to 250 or -250.

[0043] On the other hand, in general, air conditioning units preset a fixed valve opening of the electronic expansion valve before starting the compressor, and then start the compressor to adjust the valve opening. However, this method cannot cope with the changing external environment. For example, the ambient temperature of the air-cooled chilled water refrigeration unit is -5℃ and the ambient temperature is 35℃ all year round. If the same method is used, it will definitely not be applicable and cannot take into account the two conditions at the same time.

[0044] In this regard, in an embodiment of the present invention, before the compressor is started, the electronic expansion valve operates at a basic valve opening, and after the compressor is started, the electronic expansion valve is adjusted based on the basic valve opening. The basic valve opening D is dynamically adjusted using the following formula: ; in, is the preset valve opening corresponding to the reference cooling medium temperature, is the current cooling medium temperature, is the reference cooling medium temperature, is the pre-opening adjustment coefficient. Specifically, is 20.

[0045] When the air conditioning unit is an air-cooled chiller, is the preset valve opening corresponding to the reference ambient temperature, is the current ambient temperature, is the reference ambient temperature.

[0046] When the air conditioning unit is a water-cooled chiller, is the preset valve opening corresponding to the reference cooling water temperature, is the current cooling water temperature, is the reference cooling water temperature.

[0047] In summary, the present invention discloses an adjustment control method for an electronic expansion valve of an air-conditioning unit, which collects state parameters of a compressor in an air-conditioning unit under various states, and respectively calculates the valve opening of the adjusted electronic expansion valve under each state parameter, and then comprehensively calculates the adjustment value of the total valve opening. Thus, this control method can improve the response speed and control accuracy of the compressor. This precise control ensures that the compressor can maintain the best operating state under various complex working conditions. In addition, the method particularly considers the safety under special working conditions, that is, under special working conditions, the method can automatically adjust the opening of the electronic expansion valve to protect core components such as the compressor from overload or damage. Furthermore, by setting the adjustment valve opening of the electronic expansion valve to a comprehensive calculation value, the control process is simplified. There is no need for manual judgment and setting of entry and exit conditions for various states, which reduces the complexity of operation and human errors.

[0048] In another preferred embodiment of the present invention, an air-conditioning unit is disclosed, which includes a controller, a compressor and an electronic expansion valve connected to the compressor, and the controller controls the valve opening of the electronic expansion valve based on the air-conditioning unit electronic expansion valve adjustment control method in the above embodiment.

[0049] The present invention also discloses another air-conditioning unit electronic expansion valve adjustment control system, which includes one or more processors, a memory and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the program includes instructions for executing the air-conditioning unit electronic expansion valve adjustment control method as described above. The processor can adopt a general central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits, which are used to execute relevant programs to realize the functions required to be executed by the modules in the control system of the embodiment of the present application, or to execute the control method of the method embodiment of the present application.

[0050] The present invention also discloses a computer-readable storage medium, which includes a computer program, and the computer program can be executed by a processor to complete the above-mentioned air conditioning unit electronic expansion valve adjustment control method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, a data center, etc. that includes one or more available media integrated. The available medium can be a read-only memory (ROM), or a random access memory (RAM), or a magnetic medium, such as a floppy disk, a hard disk, a tape, a magnetic disk, or an optical medium, such as a digital versatile disc (DVD), or a semiconductor medium, such as a solid state disk (SSD), etc.

[0051] The embodiment of the present application also discloses a computer program product or a computer program, which includes a computer instruction stored in a computer-readable storage medium. A processor of an electronic device reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the electronic device executes the above-mentioned air conditioning unit electronic expansion valve adjustment control method.

[0052] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A method for adjusting and controlling an electronic expansion valve of an air conditioning unit, characterized in that: include: Collecting state parameters of a compressor in an air-conditioning unit, the state parameters including a first state parameter related to temperature control and a plurality of second state parameters related to safety protection control of the compressor; Calculating a first adjustment value for adjusting the valve opening of the electronic expansion valve based on the first state parameter and a preset first setting value corresponding to the first state parameter; Calculating a second adjustment value for adjusting the valve opening of the electronic expansion valve based on the second state parameter and a preset second setting value corresponding to the second state parameter; The first adjustment value and the second adjustment value reflect the direction and the number of steps for adjusting the valve opening of the electronic expansion valve; The valve opening of the electronic expansion valve is adjusted based on a comprehensive calculation value of the first adjustment value and the second adjustment value.

2. The method for adjusting and controlling the electronic expansion valve of an air conditioning unit according to claim 1, characterized in that: The first state parameter includes suction superheat, and the first adjustment value A is calculated based on the following formula: ； in, is the current suction superheat of the compressor, is the suction superheat degree related to the target temperature. 1 Adjustment factor for automatic control.

3. The method for adjusting and controlling the electronic expansion valve of an air conditioning unit according to claim 1, characterized in that: The second state parameter includes the low pressure value of the low pressure side of the compressor. The second adjustment value B1 related to the low pressure too high protection is calculated based on the following formula, and the second adjustment value B2 related to the low pressure too low protection is calculated: ； ； When B1>0, adjust B1 to 0; When B2<0, adjust B2 to 0; in, is a preset temperature value related to the low pressure over-high protection value of the compressor, is a preset temperature value related to the low pressure protection value of the compressor, is the evaporation temperature obtained by converting the currently collected pressure on the low-pressure side of the compressor, 2 It is the low voltage over-high protection adjustment coefficient. It is the low voltage protection adjustment coefficient.

4. The air conditioning unit electronic expansion valve adjustment control method according to claim 1, characterized in that: The second state parameter includes the exhaust gas superheat of the compressor, and the second adjustment value B3 is calculated based on the following formula: ； When B3>0, adjust B3 to 0; in, is the current exhaust gas superheat of the compressor, is the exhaust gas superheat protection value of the compressor set, It is the exhaust superheat protection adjustment coefficient.

5. The air conditioning unit electronic expansion valve adjustment control method according to claim 1, characterized in that: The second state parameter includes the pressure difference between the high-pressure side and the low-pressure side of the compressor. The second adjustment value B4 is calculated based on the following formula: ； When B4>0, adjust B4 to 0; in, is the current pressure difference between the high-pressure side and the low-pressure side of the compressor, is the protection value of the pressure difference between the high-pressure side and the low-pressure side of the compressor, It is the pressure difference protection adjustment coefficient.

6. The method for adjusting and controlling the electronic expansion valve of an air conditioning unit according to claim 1, characterized in that: The state parameter further includes a third state parameter related to the load of the air conditioning unit, and a third adjustment value for adjusting the valve opening of the electronic expansion valve is calculated based on the third state parameter and a preset third setting value corresponding to the third state setting parameter; The third adjustment value C is calculated based on the following formula: ； in, is the current difference between the compressor in the current acquisition cycle and the previous acquisition cycle, is the load change valve opening adjustment coefficient.

7. The method for adjusting and controlling an electronic expansion valve of an air conditioning unit according to claim 1, characterized in that: Before the compressor is started, the electronic expansion valve operates at a basic valve opening, and the basic valve opening D is dynamically adjusted according to the following formula: ； in, is the preset valve opening corresponding to the reference ambient temperature, is the current ambient temperature, is the reference ambient temperature; is the pre-opening adjustment coefficient.

8. An air conditioning unit, characterized in that: It comprises a controller, a compressor and an electronic expansion valve connected to the compressor, wherein the controller controls the valve opening of the electronic expansion valve based on the air conditioning unit electronic expansion valve adjustment control method according to any one of claims 1 to 7.

9. An electronic expansion valve adjustment control system for an air conditioning unit, characterized in that: include: one or more processors; Memory; And one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the programs include instructions for executing the air conditioning unit electronic expansion valve adjustment control method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: It includes a computer program, which can be executed by a processor to complete the air-conditioning unit electronic expansion valve adjustment control method as described in any one of claims 1 to 7.

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