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

Abstract

The application discloses an air conditioning unit electronic expansion valve adjustment control method and system and an air conditioning unit. The method comprises the following steps: collecting state parameters of a compressor in the air conditioning unit, wherein the state parameters comprise first state parameters 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 a valve opening degree of the electronic expansion valve based on the first state parameters and corresponding first set values; calculating a second adjustment value for adjusting the valve opening degree of the electronic expansion valve based on the second state parameters and corresponding second set values; 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 above method, the electronic expansion valve can be efficiently, accurately and stably controlled to meet the diversity of various customer working conditions. Moreover, in special working conditions, the safety of core components such as the compressor can be ensured, and the safe and stable operation of the unit can also be ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning control, and particularly relates to an air conditioning unit electronic expansion valve adjustment control method and system and an air conditioning unit. BACKGROUND

[0002] In the design and application process of an air conditioning system, the adjustment control of an electronic expansion valve is crucial to the performance and safety of the unit. Traditional water chillers usually use a proportional-integral-derivative (PID) algorithm to control the electronic expansion valve. However, the PID control has many limitations when dealing with complex operating condition changes.

[0003] When the operating condition of the unit exceeds the normal operating range of the compressor, the electronic expansion valve needs to take 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 valve switching, although it can temporarily ensure the safety range of certain parameters, can easily lead to unstable operation of the unit. This instability not only affects the performance of the air conditioning system, but also can cause noise and vibration problems, thereby affecting the comfort and long-term safety of the user.

[0004] A more complex problem is that when the unit needs to cope with multiple operating conditions at the same time, such as some parameters needing to open the valve for protection, while other parameters needing to close the valve for 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 state of the unit, and can cause other parameters to deteriorate, exacerbating the instability of the unit operation.

[0005] In addition, as the demand for water chillers in different industries continues to develop, users have increasingly high requirements for the diversity of unit operating conditions. The traditional method of customizing protection parameters to meet the needs of specific customers has become inadequate. Therefore, the existing electronic expansion valve control method is difficult to adapt to the diversified needs of the market, SUMMARY

[0006] The purpose of the present application is to provide an air conditioning unit electronic expansion valve adjustment control method and system and an air conditioning unit that can comprehensively judge the valve opening of the electronic expansion valve based on various state parameters of the compressor to make the electronic expansion valve self-adapt to multiple different operating conditions.

[0007] To achieve the above purpose, the present application provides an air conditioning unit electronic expansion valve adjustment control method, which comprises:

[0008] Collecting state parameters of a compressor in an air conditioning unit, the state parameters including first state parameters related to temperature control and second state parameters related to safety protection control of the compressor;

[0009] Calculating a first adjustment value for adjusting the valve opening degree of the electronic expansion valve based on the first state parameters and preset first set values corresponding to the first state parameters;

[0010] Calculating a second adjustment value for adjusting the valve opening degree of the electronic expansion valve based on the second state parameters and preset second set values corresponding to the second state parameters;

[0011] The first adjustment value and the second adjustment value reflect the direction and number of steps for adjusting the valve opening degree of the electronic expansion valve;

[0012] 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.

[0013] Preferably, the first state parameters include suction superheat, and the first adjustment value A is calculated based on the following formula:

[0014] ;

[0015] Wherein, is the current suction superheat of the compressor, the current suction superheat of the compressor is collected, is the set suction superheat related to the target temperature, 1 is an automatic control adjustment coefficient.

[0016] Preferably, the second state parameters include the low pressure value of the low pressure side of the compressor, the second adjustment value B1 related to low pressure overhigh protection is calculated based on the following formula, and the second adjustment value B2 related to low pressure underprotection is calculated:

[0017] ;

[0018] ;

[0019] When B1>0, B1 is adjusted to 0; when B2<0, B2 is adjusted to 0;

[0020] Wherein, is the preset temperature value related to the low pressure overhigh protection value of the compressor, is the preset temperature value related to the low pressure underprotection value of the compressor, is the evaporation temperature converted from the current collected pressure of the low pressure side of the compressor, 2 is a low pressure overhigh protection adjustment coefficient, is a low pressure over low protection adjustment coefficient.

[0021] Preferably, the second state parameter comprises a discharge superheat of the compressor, and the second adjustment value B3 is calculated based on the following formula:

[0022] ;

[0023] When B3>0, B3 is adjusted to 0;

[0024] wherein, is a current discharge superheat of the compressor, is a set discharge superheat protection value of the compressor, is a discharge superheat protection adjustment coefficient.

[0025] Preferably, the second state parameter comprises a pressure difference between a high pressure side and a low pressure side of the compressor, and the second adjustment value B4 is calculated based on the following formula:

[0026] ;

[0027] When B4>0, B4 is adjusted to 0;

[0028] wherein, is a current pressure difference between a high pressure side and a low pressure side of the compressor, is a set pressure difference protection value between a high pressure side and a low pressure side of the compressor, is a pressure difference protection adjustment coefficient.

[0029] Preferably, the state parameter further comprises a third state parameter related to a load of the air conditioning unit, and a third adjustment value for adjusting the valve opening degree of the electronic expansion valve is calculated based on the third state parameter and a third set value corresponding to the third state parameter.

[0030] The third adjustment value C is calculated based on the following formula:

[0031] ;

[0032] wherein, is a current load change valve opening adjustment coefficient, is a load change valve opening adjustment coefficient.

[0033] Preferably, before the compressor is started, the electronic expansion valve works at a basic valve opening degree, and the basic valve opening degree D is dynamically adjusted based on the following formula:

[0034] ;

[0035] wherein, is a preset valve opening degree corresponding to the reference ambient temperature, is a current ambient temperature, is the reference ambient temperature; is a preset opening degree adjustment coefficient.

[0036] The present application also provides an air conditioning unit, which comprises a controller, a compressor and an electronic expansion valve connected to the compressor, wherein the controller controls the valve opening degree of the electronic expansion valve based on the air conditioning unit electronic expansion valve adjustment control method as described above.

[0037] The present application also provides an air conditioning unit electronic expansion valve adjustment control system, which comprises:

[0038] one or more processors;

[0039] a memory;

[0040] and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the programs comprise instructions for executing the air conditioning unit electronic expansion valve adjustment control method as described above.

[0041] The present application also provides a computer readable storage medium comprising a computer program, which can be executed by a processor to complete the air conditioning unit electronic expansion valve adjustment control method as described above.

[0042] Compared with the prior art, the air conditioning unit electronic expansion valve adjustment control method provided by the above technical solution of the present application collects the state parameters of the compressor in the air conditioning unit under various states, respectively calculates the adjustment valve opening degree of the electronic expansion valve under each state parameter, and then comprehensively calculates the adjustment value of the total valve opening degree. Thus, this control method can improve the response speed and control accuracy of the compressor. This accurate control ensures that the compressor can maintain the best operating state under various complex working conditions. In addition, this method particularly considers the safety under special working conditions, that is, under special working conditions, the method can automatically adjust the opening degree of the electronic expansion valve to protect the core components such as the compressor and prevent overloading or damage. Furthermore, by setting the adjustment valve opening degree of the electronic expansion valve as the comprehensive calculation value, the control process is simplified. There is no need for artificial judgment and setting of the entry and exit conditions of various states, which reduces the operation complexity and human error. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a flowchart of the air conditioning unit electronic expansion valve adjustment control method in the embodiments of the present application. DETAILED DESCRIPTION

[0044] To explain the technical content, structural features, achieved purposes and effects of the present application in detail, the following will be described in detail in combination with the embodiments and the accompanying drawings.

[0045] The present embodiment discloses an electronic expansion valve adjustment control method for air conditioning unit, which is used to automatically adjust the valve opening of the electronic expansion valve connected with the compressor in the air conditioning unit, to ensure the working performance of the compressor and the safety performance of the compressor. For this purpose, the control method comprises the following steps: Figure 1

[0046] S1: Collecting the state parameters of the compressor in the air conditioning unit, which include the first state parameters related to temperature control and several second state parameters related to the safety protection control of the compressor.

[0047] S20: Calculating the first adjustment value for adjusting the valve opening of the electronic expansion valve based on the first state parameters and the preset first set value corresponding to the first state parameters.

[0048] S21: Calculating the second adjustment value for adjusting the valve opening of the electronic expansion valve based on the second state parameters and the preset second set value corresponding to the second state parameters.

[0049] 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.

[0050] S3: Adjusting the valve opening of the electronic expansion valve based on the comprehensive calculation value of the first adjustment value and the second adjustment value.

[0051] For example, in the current adjustment period, the first adjustment value is 100, and the second adjustment value is -50. The adjustment value of the valve opening is positive, which represents the execution of the valve opening operation in the current state. The adjustment value of the valve opening is negative, which represents the execution of the valve closing operation in the current state. For this purpose, since the comprehensive calculation value of the first adjustment value and the second adjustment value is 50, in the current adjustment period, the valve opening operation of 50 steps is executed on the electronic expansion valve to increase the valve opening of the electronic expansion valve.

[0052] In addition, in the current adjustment period, 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 period, the valve closing operation of 50 steps is executed on the electronic expansion valve to reduce the valve opening of the electronic expansion valve.

[0053] Furthermore, in the current adjustment period, 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 period, no operation is executed on the electronic expansion valve, so that the valve opening of the electronic expansion valve remains in the current state.​

[0054] On the other hand, the first state parameter is used for adjustment of the electronic expansion valve in the normal operation state of the compressor, so that the temperature at the air outlet of the air conditioning unit is within the set target range. The first state parameter can be suction superheat, evaporator liquid level, condenser liquid level, discharge superheat, etc. Taking the suction superheat as the first state parameter as an example, the first adjustment value A is calculated based on the following formula:

[0055] ;

[0056] wherein, is the current suction superheat of the compressor, the is the set suction superheat related to the target temperature, 1 is an automatic control adjustment coefficient. In the present embodiment, 1 is 10.

[0057] On the other hand, the second state parameter includes any one or more of the low pressure value of the low pressure side of the compressor, the discharge superheat of the compressor, and the pressure difference between the high pressure side and the low pressure side of the compressor.

[0058] Specifically, when the low pressure value of the low pressure side of the compressor is taken as the second state parameter, adjustment control of the electronic expansion valve is performed from both the low pressure overhigh protection and the low pressure overlow protection. For this purpose, the second adjustment value B1 related to the low pressure overhigh protection is calculated based on the following formula, and the second adjustment value B2 related to the low pressure overlow protection is calculated:

[0059] ;

[0060] ;

[0061] wherein, is a preset temperature value related to the low pressure overhigh protection value of the compressor, is a preset temperature value related to the low pressure overlow protection value of the compressor, is the evaporation temperature converted from the current collected pressure of the low pressure side of the compressor, 2 is a low pressure overhigh protection adjustment coefficient, is a low pressure overlow protection adjustment coefficient. For example, 2 is 90, is 80.

[0062] In the operation of the air conditioning unit, if the actual evaporation temperature > low pressure over high protection value, exceeding the normal operating range of the compressor set, the electronic expansion valve needs to be closed to reduce the evaporation temperature, to prevent the compressor from running out of the operating range. Therefore, B1 must be less than 0, if the calculated B1 > 0, adjust B1 to 0.

[0063] Similarly, in the operation of the air conditioning unit, if the actual evaporation temperature < low pressure over low protection value, this state exceeds the normal operating range of the compressor set, the electronic expansion valve needs to be opened to increase the evaporation temperature, to prevent the compressor from running out of the operating range. Therefore, B2 must be greater than 0, if the calculated B2 < 0, adjust B2 to 0.

[0064] In this embodiment, when the compressor enters the low pressure over low or low pressure over high protection state, the corresponding electronic expansion valve adjustment value is calculated, and then the adjustment value calculated based on other state parameters is comprehensively calculated.

[0065] When the discharge superheat of the compressor is taken as the second state parameter, the second adjustment value B3 is calculated based on the following formula:

[0066] ;

[0067] Wherein, is the current discharge superheat of the compressor, is the set discharge superheat protection value of the compressor, is the discharge superheat protection adjustment coefficient. Specifically, is 75.

[0068] In this embodiment, in the operation of the air conditioning unit, if the actual discharge superheat < discharge superheat protection value, this state will affect the safety of the compressor, such as liquid return, oil running, etc., the electronic expansion valve needs to be closed to increase the discharge superheat, to prevent this unsafe state. Therefore, if the calculated B3 > 0, adjust B3 to 0.

[0069] When the pressure difference between the high pressure side and the low pressure side of the compressor is taken as the second state parameter, the second adjustment value B4 is calculated based on the following formula:

[0070] ;

[0071] Wherein, is the current pressure difference between the high pressure side and the low pressure side of the compressor, is the set pressure difference protection value between the high pressure side and the low pressure side of the compressor, is the pressure difference protection adjustment coefficient. Specifically, is 80.

[0072] In the embodiment, if the actual high-low pressure difference < the high-low pressure difference protection value during the operation of the air conditioning unit, this state will cause the compressor to return oil not in time and damage the compressor, and the electronic expansion valve needs to be closed to increase the high-low pressure difference to prevent this unsafe state. Therefore, if B4 > 0 is calculated, B4 is adjusted to 0.

[0073] On the other hand, the state parameters further include a third state parameter related to the load of the air conditioning unit, and a third adjustment value for adjusting the valve opening degree of the electronic expansion valve is calculated based on the third state parameter and a preset third set value corresponding to the third state set parameter.

[0074] Then, in the embodiment, the third adjustment value C is calculated based on the following formula:

[0075] ;

[0076] wherein, is the current cycle and the previous cycle of the compressor current difference, is the load change valve opening degree adjustment coefficient. Specifically, the is 20.

[0077] In summary, when multiple adjustment values are calculated according to various state parameters, for example, A, B1 or B2, B3, B4, C, the total step number Z = A + B1(B2) + B3 + B4 + C is calculated.

[0078] On the other hand, the extreme value of the total step number Z of the current cycle calculated can also be limited to ensure that the adjustment step number can be executed in place within a single cycle, avoiding the execution of the next cycle adjustment without being executed in place, causing the valve body actual value to be inconsistent with the program calculation value of the electronic expansion valve step number.

[0079] Specifically, Z satisfies the following limit condition:

[0080] -N ≤ Z ≤ N;

[0081] N = W * P;

[0082] wherein, W is the opening degree calculation period of the electronic expansion valve, and P is the step frequency of the electronic expansion valve. For example, W is 2S, and P is 250 steps / S, then -250 ≤ Z ≤ 250.

[0083] Then, when the total step number Z calculated is greater than 250 or less than -250, Z is adjusted to 250 or -250.

[0084] In another aspect, a general air conditioning unit presets a fixed valve opening degree of an electronic expansion valve before starting a compressor, and then starts the compressor to adjust the valve opening degree. However, this method cannot cope with various working conditions of external environment, for example, the air-cooled chilled water unit has an environment temperature of -5℃ and an environment temperature of 35℃. If the same method is used, it is certainly not applicable, and cannot take into account both conditions.

[0085] To this end, in the embodiment of the present application, before the compressor is started, the electronic expansion valve works at a basic valve opening degree, and after the compressor is started, the basic valve opening degree is adjusted. The basic valve opening degree D is dynamically adjusted according to the following formula:

[0086] ;

[0087] Wherein, is a preset valve opening degree corresponding to a reference cooling medium temperature, is a current cooling medium temperature, is the reference cooling medium temperature, is a pre-opening adjustment coefficient. Specifically, is 20.

[0088] When the air conditioning unit is an air-cooled chilled water unit, is a preset valve opening degree corresponding to a reference environment temperature, is a current environment temperature, is the reference environment temperature.

[0089] When the air conditioning unit is a water-cooled chilled water unit, is a preset valve opening degree corresponding to a reference cooling water temperature, is a current cooling water temperature, is the reference cooling water temperature.

[0090] In summary, the present application discloses an air conditioning unit electronic expansion valve adjustment control method, which collects state parameters of the compressor in various states of the air conditioning unit, and calculates the valve opening degree of the electronic expansion valve under each state parameter, and then comprehensively calculates the adjustment value of the total valve opening degree. Thus, this control method can improve the response speed and control accuracy of the compressor. This accurate control ensures that the compressor can maintain the best operating state under various complex working conditions. In addition, this method particularly considers the safety under special working conditions, that is, under special working conditions, the method can automatically adjust the opening degree of the electronic expansion valve to protect the core components such as the compressor and prevent overloading or damage. Furthermore, by setting the adjustment valve opening degree of the electronic expansion valve to the comprehensive calculation value, the control process is simplified. There is no need for artificial judgment and setting of the entry and exit conditions of various states, which reduces the operation complexity and human error.

[0091] In another preferred embodiment of the present application, an air conditioning unit is disclosed, which comprises a controller, a compressor, and an electronic expansion valve connected to the compressor, and the controller controls the valve opening degree of the electronic expansion valve based on the electronic expansion valve adjustment control method of the air conditioning unit in the above-mentioned embodiments.

[0092] The present application also discloses another air conditioning unit electronic expansion valve adjustment control system, which comprises one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the programs comprise instructions for executing the air conditioning unit electronic expansion valve adjustment control method as described above. The processor can be a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits, for executing relevant programs to achieve the functions required by the modules in the control system of the embodiments of the present application, or to execute the control method of the method embodiments of the present application.

[0093] The present application also discloses a computer-readable storage medium comprising a computer program, which can be executed by a processor to complete the air conditioning unit electronic expansion valve adjustment control method as described above. The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server, data center, etc. integrated with one or more available media. 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 magnetic tape, a magnetic disc, or an optical medium such as a digital versatile disc (DVD), or a semiconductor medium such as a solid state disk (SSD), etc.

[0094] The embodiments of the present application also disclose a computer program product or a computer program, which comprises computer instructions stored in a computer-readable storage medium. The processor of an electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions to make the electronic device execute the air conditioning unit electronic expansion valve adjustment control method as described above.

[0095] The above disclosure is merely the preferred embodiments of the present application and is not intended to limit the scope of the present application. Any equivalent changes made according to the patentable scope of the present application shall still fall within the scope of the present application.

Claims

1. An electronic expansion valve adjustment control method for an air conditioning unit, characterized by, Comprising: collecting state parameters of a compressor in an air conditioning unit, the state parameters including first state parameters related to temperature control and second state parameters related to safety protection control of the compressor; calculating a first adjustment value for adjusting the valve opening degree of the electronic expansion valve based on the first state parameters and preset first set values corresponding to the first state parameters; calculating a second adjustment value for adjusting the valve opening degree of the electronic expansion valve based on the second state parameters and preset second set values corresponding to the second state parameters; the first adjustment value and the second adjustment value reflect the direction and number of steps for adjusting the valve opening degree of the electronic expansion valve; adjusting the valve opening degree of the electronic expansion valve based on the comprehensive calculation value of the first adjustment value and the second adjustment value; the second state parameters include a low pressure value of the low pressure side of the compressor, the second adjustment value B1 related to low pressure over-protection is calculated based on the following formula, and the second adjustment value B2 related to low pressure under-protection is calculated: when B1>0, B1 is adjusted to 0; when B2<0, B2 is adjusted to 0; wherein, T is a preset temperature value related to the low pressure over high protection value of the compressor, T is a preset temperature value related to the low pressure over low protection value of the compressor, 蒸发 X1 is the evaporation temperature converted from the current collected pressure on the low pressure side of the compressor, X2 is a low pressure over high protection adjustment coefficient, and X3 is a low pressure over low protection adjustment coefficient.

2. The air handling unit electronic expansion valve adjustment control method of claim 1, wherein, the first state parameters include suction superheat, and the first adjustment value A is calculated based on the following formula: A = (ΔT 吸气 - ΔT 设定吸气 )*X1; where ΔT 吸气 is the current suction superheat of the compressor, ΔT 设定吸气 is a set suction superheat related to a target temperature, and X1 is an automatic control adjustment coefficient.

3. The air handling unit electronic expansion valve adjustment control method of claim 1, wherein, the second state parameters include discharge superheat of the compressor, and the second adjustment value B3 is calculated based on the following formula: B3 = (ΔT 排气 - ΔT 设定排气 )* X4; when B3>0, B3 is adjusted to 0; where ΔT 排气 is the current discharge superheat of the compressor, ΔT 设定排气 is a set discharge superheat protection value of the compressor, and X4 is a discharge superheat protection adjustment coefficient.

4. The air handling unit electronic expansion valve adjustment control method of claim 1, wherein, the second state parameters include 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: B4 = (ΔF - ΔF 设定 )*X5; when B4>0, B4 is adjusted to 0; wherein ΔF is the current pressure difference between the high and low pressure sides of the compressor, ΔF 设定 is a set protection value for the pressure difference between the high and low pressure sides of the compressor, and X5 is a pressure difference protection adjustment coefficient.

5. The air handling unit electronic expansion valve adjustment control method of claim 1, wherein, the state parameters further include third state parameters related to the load of the air conditioning unit, and a third adjustment value for adjusting the valve opening degree of the electronic expansion valve is calculated based on the third state parameters and preset third set values corresponding to the third state set parameters; the third adjustment value C is calculated based on the following formula: C=ΔI*X6; wherein ΔI is the current cycle and the previous cycle of the compressor current difference value, and X6 is the load change valve opening degree adjustment coefficient.

6. The air handling unit electronic expansion valve adjustment control method of claim 1, wherein, Before the compressor starts, the electronic expansion valve works at a basic valve opening degree, and the basic valve opening degree D is dynamically adjusted according to the following formula: D = D0+ (T 当前 - T 参考 )* X7; wherein D0 is a preset valve opening degree corresponding to a reference ambient temperature, T 当前 is a current ambient temperature, T 参考 is the reference ambient temperature; and X7 is a pre-opening degree adjustment coefficient.

7. An air conditioning unit characterized by, Comprising a controller, a compressor and an electronic expansion valve connected with the compressor, the controller controls the valve opening degree of the electronic expansion valve based on the air conditioning unit electronic expansion valve adjustment control method of any one of claims 1 to 6.

8. An air handling unit electronic expansion valve trim control system, comprising: Comprising: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for executing the air conditioning unit electronic expansion valve adjustment control method of any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, Comprising a computer program, the computer program can be executed by a processor to complete the air conditioning unit electronic expansion valve adjustment control method of any one of claims 1 to 6.

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