Adjustment methods for the initial, operational, and shut-off phases of an electronic expansion valve.

Abstract

This invention relates to the field of electronic expansion valve regulation technology, specifically to a method for regulating the initial, operational, and closing stages of an electronic expansion valve. The invention includes the following steps: S1, acquiring the current ambient temperature and the current actual water temperature; S2, inputting the acquired ambient temperature and actual water temperature into a preset initial opening calculation model to obtain the initial opening value of the electronic expansion valve; S3, adjusting the initial opening of the electronic expansion valve according to the acquired initial opening value. This invention, by dynamically calculating the initial opening of the electronic expansion valve, avoids the regulation lag caused by a fixed opening, shortens the system's time from startup to stability, thereby ensuring rapid response and stable operation under extreme conditions such as high-temperature cooling and low-temperature heating, and overcoming the limitations of traditional fixed opening control.

Description

Technical Field

[0001] This invention relates to the field of electronic expansion valve adjustment technology, specifically to adjustment methods for the initial, operation, and closing stages of an electronic expansion valve. Background Technology

[0002] In air conditioning system design, the electronic expansion valve, as an electronic control element, controls its opening degree by controlling the system superheat to achieve the purpose of controlling the compressor exhaust temperature. Due to its advantages such as high precision, fast and accurate operation, and significant energy-saving effect, it is widely used in refrigeration and air conditioning.

[0003] Current methods for controlling the opening of the electronic expansion valve in variable frequency air conditioning units primarily involve directly presetting a fixed initial opening at startup, and then using conventional adjustment strategies to control the valve's operating opening by adjusting the predetermined range of increase or decrease. However, in actual operation, when the air conditioning unit is used for heating in low-temperature environments and cooling in high-temperature environments, the ambient temperature fluctuates significantly, ranging from approximately -35°C to 43°C. Furthermore, during startup, the water temperature of the air conditioning unit is approximately between 10°C and 60°C. If the electronic expansion valve maintains a fixed opening in the initial stage under different operating conditions, it will obviously lead to a prolonged time required for the air conditioning unit to stabilize from startup in most situations. Therefore, a solution is urgently needed. Summary of the Invention

[0004] To avoid and overcome the technical problems existing in the prior art, the present invention provides a method for adjusting the initial stage, operation stage and closing stage of an electronic expansion valve. By dynamically calculating the initial opening degree of the electronic expansion valve, the adjustment lag caused by the fixed opening degree is avoided, and the time from system start-up to stability is shortened, thereby ensuring rapid response and stable operation under extreme conditions such as high temperature cooling and low temperature heating, and overcoming the limitations of traditional fixed opening degree control.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The initial adjustment method for an electronic expansion valve includes the following steps:

[0007] S1. Obtain the current ambient temperature and the current actual water temperature;

[0008] S2. Input the acquired ambient temperature and actual water temperature into the preset initial opening calculation model to obtain the initial opening value of the electronic expansion valve.

[0009] The initial opening calculation model is as follows:

[0010] P EXVE1 =EXV1+(T wJ -T w )*P+(T a -TaJ )*M

[0011] In the formula: P EXVE1 This represents the initial opening value of the electronic expansion valve, in pls.

[0012] EXV1 is the rated opening, in pls;

[0013] T wJ The water temperature is the baseline, and the unit is °C.

[0014] T win The actual current water temperature, in °C;

[0015] T a The current ambient temperature is expressed in °C.

[0016] T aJ The ambient temperature is the baseline, and the unit is °C.

[0017] P is the water temperature influence coefficient;

[0018] M is the environmental temperature influence coefficient;

[0019] S3. Adjust the initial opening of the electronic expansion valve according to the obtained initial opening value.

[0020] The adjustment method during the operation phase applies the initial adjustment method of the electronic expansion valve described above. After the unit starts up, the initial opening value is maintained for a fixed adjustment cycle; the compressor discharge temperature T is continuously acquired. d 1. Compressor fin temperature T def The superheat of the compressor's exhaust gas, T dsh and the current opening value P of the electronic expansion valve i And before each fixed adjustment cycle of the subsequent electronic expansion valve, the predetermined opening increase or decrease range of the electronic expansion valve is generated according to the conventional adjustment strategy;

[0021] Before each subsequent fixed adjustment cycle, first determine T. d and T dsh If the range is abnormal, adjust the electronic expansion valve according to the exhaust anomaly strategy and the superheat anomaly strategy respectively; otherwise, determine T. def Is it an abnormal interval? If T def If it is in an abnormal range, adjust the electronic expansion valve according to the fin abnormality strategy; if T def If it is not in an abnormal range, adjust the electronic expansion valve according to the optimization and adjustment strategy;

[0022] In addition, if the compressor frequency changes within each fixed adjustment cycle, the frequency opening increment or decrement is generated according to the conventional frequency adjustment strategy, and the opening of the electronic expansion is adjusted according to the frequency opening increment or decrement before each fixed adjustment cycle.

[0023] As a further aspect of the present invention: the optimized adjustment strategy specifically involves: obtaining the cumulative continuous increase or decrease of several prior fixed adjustment cycles, and obtaining the exhaust temperature difference between the end of the previous fixed adjustment cycle and the beginning of the previous fixed adjustment cycle; subsequently, determining the current opening value P of the electronic expansion valve. i The system checks whether the cumulative continuous decrease or increase in exhaust temperature difference falls within the set range. If it does not exceed the decrease threshold or increase threshold corresponding to the set range, the electronic expansion valve is directly adjusted according to the predetermined opening increment / decrease. If it exceeds the decrease threshold, the electronic expansion valve is limited to opening the valve for several fixed adjustment cycles. If it exceeds the increase threshold, the system further checks whether the exhaust temperature difference exceeds the temperature increase threshold. If it does, the electronic expansion valve is limited to opening the valve for several fixed adjustment cycles. If it does not exceed the temperature increase threshold, the electronic expansion valve is limited to closing the valve for several fixed adjustment cycles.

[0024] As a further aspect of the present invention: in the optimization and adjustment strategy:

[0025] When P i When the temperature difference is greater than 240 pls, the exhaust temperature difference of the previous fixed adjustment cycle is within the full range, and the reduction threshold is 8% of the current opening; the increase threshold is 6% of the current opening.

[0026] When 160pls≤P i When the exhaust temperature difference is ≤240pls, the exhaust temperature difference of the previous fixed adjustment cycle is within the full range, and the reduction threshold is 6% of the current opening degree; when the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 4℃, the increase threshold is 5% of the current opening degree; when the exhaust temperature difference of the previous fixed adjustment cycle is greater than 4℃, the increase threshold is 4% of the current opening degree.

[0027] When P iWhen the temperature difference is less than 160 pls, if the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 1℃, the reduction threshold is 6% of the current opening; if the temperature increase of the previous fixed adjustment cycle is greater than 1℃, the reduction threshold is 5% of the current opening. If the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 1.5℃, the increase threshold is 5% of the current opening; if the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 2.5℃ and greater than or equal to 1.5℃, the increase threshold is 4% of the current opening; if the exhaust temperature difference of the previous fixed adjustment cycle is greater than 2.5℃, the increase threshold is 3% of the current opening.

[0028] As a further aspect of the present invention: in the optimization and adjustment strategy:

[0029] When P i >240pls, and the electronic expansion valve opening was decreasing in the previous fixed adjustment cycle:

[0030] If the exhaust temperature difference is less than or equal to 2℃, then in a subsequent fixed adjustment cycle, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0031] If the exhaust temperature difference is greater than 2℃ and less than or equal to 4℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0032] If the exhaust temperature difference is greater than 4℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve will be limited to performing adjustment operations with a predetermined opening degree increase or decrease of only the valve opening range.

[0033] When P i >240pls, and the electronic expansion valve opening was increasing in the previous fixed adjustment cycle:

[0034] The temperature rise threshold at this time is 2℃. If the exhaust temperature difference is less than or equal to 2℃, then in the next two fixed cycles, the electronic expansion valve is limited to performing the predetermined opening increase or decrease range adjustment operation of closing the valve.

[0035] If the exhaust temperature difference is greater than 2℃ and less than or equal to 5℃, then in a subsequent fixed cycle, the electronic expansion valve is limited to performing only the predetermined opening adjustment operation.

[0036] If the exhaust temperature difference is greater than 5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increase or decrease range of opening the valve.

[0037] When 160pls≤P i ≤240pls, and the opening of the electronic expansion valve was decreasing in the previous fixed adjustment cycle;

[0038] If the exhaust temperature difference is less than or equal to 2℃, then in a subsequent fixed adjustment cycle, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0039] If the exhaust temperature difference is greater than 2℃ and less than or equal to 3℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0040] If the exhaust temperature difference is greater than 3℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening degree increase or decrease range of opening the valve.

[0041] When 160pls≤P i ≤240pls, and the electronic expansion valve opening was increasing in the previous fixed adjustment cycle;

[0042] The temperature rise threshold at this time is 1.5℃. If the exhaust temperature difference is less than or equal to 1.5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing the adjustment operation of closing the valve only by the predetermined opening increase or decrease range.

[0043] If the exhaust temperature difference is greater than 1.5℃ and less than or equal to 4℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0044] If the exhaust temperature difference is greater than 4℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increase or decrease range of opening the valve.

[0045] When P i <160pls, and the electronic expansion valve opening was decreasing in the previous fixed adjustment cycle:

[0046] If the exhaust temperature difference is less than or equal to 1℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0047] If the exhaust temperature difference is greater than 1℃ and less than or equal to 2.5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening degree increase or decrease of only the valve opening range.

[0048] If the exhaust temperature difference is greater than 2.5℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening degree increase or decrease range of opening the valve.

[0049] When P i <160pls, and the electronic expansion valve opening was increasing in the previous fixed adjustment cycle:

[0050] The temperature rise threshold at this time is 1.5℃. If the exhaust temperature difference is less than or equal to 1.5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing the adjustment operation of closing the valve only by the predetermined opening increase or decrease range.

[0051] If the exhaust temperature difference is greater than 1.5℃ and less than or equal to 2.5℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0052] If the exhaust temperature difference is greater than 2.5℃, then in the subsequent two fixed adjustment cycles, if the predetermined opening increment or decrement is equal to the valve opening increment, the electronic expansion valve is limited to performing adjustment operations with the predetermined opening increment or decrement being equal to the valve opening.

[0053] As a further aspect of the present invention: the execution condition of the superheat anomaly strategy is T dsh Minimum exhaust superheat T dshmin The specific exhaust anomaly strategy is as follows: In subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations where the valve is closed only if the predetermined opening increase or decrease range is reached, until T... dsh ≥Minimum exhaust superheat T dshmin .

[0054] As a further aspect of the present invention: the execution condition of the exhaust anomaly strategy is T d For temperatures ≥105℃, the specific exhaust abnormality strategy is as follows: Obtain the first opening value of the electronic expansion valve at this time. In subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increase or decrease of the valve opening range until the exhaust temperature drops and the exhaust temperature is <100℃. At this time, the second opening value of the electronic expansion valve is obtained, and the difference between the second opening value and the first opening value is obtained. In subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increase or decrease of the valve closing range until the cumulative decrease of the electronic expansion valve in this stage is greater than or equal to 0.4 times the aforementioned difference. Two fixed adjustment cycles of the electronic expansion valve are taken as one actual adjustment cycle. After three actual adjustment cycles, the fixed adjustment cycle is restored.

[0055] As a further aspect of the present invention: the execution condition of the fin anomaly strategy is T def <Target fin temperature at the start of defrosting +2℃. The specific fin anomaly strategy is as follows: In subsequent fixed adjustment cycles, the electronic expansion valve is limited to adjusting only by a predetermined opening increment / decrement, and the opening increment / decrement is 1.5 times the predetermined opening increment / decrement, until T... dsh ≥Target fin temperature at the start of defrosting +2℃.

[0056] The adjustment method for the shutdown phase applies the adjustment method for the operation phase. When the compressor receives a shutdown command, the electronic expansion valve maintains its current opening. After the compressor shuts down to a frequency of 0Hz, the opening of the electronic expansion valve is adjusted to 80pls and maintained for 120 seconds. After that, the opening of the electronic expansion valve is adjusted to 200pls until the next start-up adjustment command is received. Then, the initial opening of the electronic expansion valve is adjusted according to the initial opening adjustment method of the electronic expansion valve.

[0057] Compared with the prior art, the beneficial effects of the present invention are:

[0058] 1. By obtaining different current actual water temperatures and current ambient temperatures, the initial opening degree of the electronic expansion valve can be specifically determined. In practical demonstration, for routine adjustments under normal conditions, different initial opening degrees were used for the electronic expansion valve, resulting in different stabilization times. Furthermore, the initial opening degree of the electronic expansion valve, which is close to the initial opening degree calculated by the aforementioned initial opening degree calculation model, resulted in the shortest time from start-up to system stabilization. This also proves that calculating the initial opening degree of the electronic expansion valve according to the initial opening degree calculation model obtained in this application can reduce the adjustment time during the process from unit start-up to system stabilization, avoid adjustment lag caused by a fixed opening degree, and shorten the system's time from start-up to stabilization. This ensures rapid response and stable operation under extreme conditions such as high-temperature cooling and low-temperature heating, overcoming the limitations of traditional fixed opening degree control.

[0059] 2. Before each fixed adjustment cycle, after generating the predetermined increase or decrease range of the electronic expansion valve opening according to the existing conventional adjustment strategy, a tiered judgment of abnormal conditions is adopted. Priority is given to addressing exhaust superheat anomalies that may cause unit runaway exhaust temperature or compressor damage to ensure system safety; secondly, fin temperature anomalies are addressed to avoid accidental defrosting; when no anomalies are found, an optimized adjustment strategy is employed to achieve precise and stable operation control. Overall, this approach balances safety, prevention of misoperation, and energy efficiency optimization.

[0060] 3. When the current opening value of the electronic expansion valve and the exhaust temperature difference are in different set ranges, this application compares the cumulative continuous decrease and cumulative continuous increase of the valve step of the electronic expansion valve with the decrease threshold and increase threshold, respectively.

[0061] If the reduction threshold is exceeded, the electronic expansion valve will be limited to performing only the predetermined opening increase or decrease range for several subsequent fixed adjustment cycles. This prevents the cumulative continuous reduction of the electronic expansion valve in adjacent cycles from causing the exhaust temperature to rise too much in subsequent fixed adjustment cycles, ensuring that the exhaust temperature is within a reasonable and stable fluctuation range, avoiding repeated adjustments of the electronic expansion valve, and enabling the system to enter the stable operation stage more quickly.

[0062] If the temperature rise threshold is exceeded, further assessment is made as to whether the exhaust temperature difference exceeds the temperature rise threshold. If it does, it indicates that the exhaust temperature rise rate is still high. Therefore, in the subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing only the predetermined opening adjustment, further reducing the exhaust temperature rise rate. If it does not exceed the threshold, it indicates that the exhaust temperature rise rate is adjusted too low. In the subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing only the predetermined opening adjustment, ensuring that the exhaust temperature remains within a reasonable and stable fluctuation range, avoiding repeated adjustments of the electronic expansion valve, and allowing the system to enter a stable operating phase more quickly.

[0063] 4. This application sets the current opening value of the electronic expansion valve to three numerical ranges: high, medium, and low. It also sets the exhaust temperature difference to three numerical ranges: high, medium, and low. When the current opening value of the electronic expansion valve and the exhaust temperature difference are in different numerical ranges, the difference between the increase threshold and the decrease threshold is optimized to ensure that the exhaust temperature fluctuation is more stable, so that the system can enter the stable operation stage more quickly.

[0064] 5. Based on the above, when the current opening value of the electronic expansion valve and the difference between the exhaust temperature are in different ranges, the number of cycles is further limited to ensure that the fluctuation of the exhaust temperature is more stable, so that the system can enter the stable operation stage more quickly.

[0065] 6. The exhaust anomaly strategy adopts a smoother adjustment method, which makes the valve closing range smaller when the electronic expansion valve is closed, thus avoiding repeated triggering of excessively high exhaust temperature and causing the system to be unable to operate stably.

[0066] 7. During the unit shutdown phase, first reduce the opening of the electronic expansion valve and hold it for a period of time, then increase it and hold it. This can prevent the electronic expansion valve from opening too much during the initial shutdown phase, which would cause a large amount of refrigerant to flow to the low-pressure side. Consequently, when restarting, the refrigerant on the low-pressure side would instantly vaporize and carry away a large amount of refrigeration oil, resulting in oil shortage. Attached Figure Description

[0067] Figure 1 This is a flowchart illustrating the initial stage of the electronic expansion valve in this invention.

[0068] Figure 2 This is a flowchart illustrating the workflow of the electronic expansion valve in this invention, which optimizes and adjusts the strategy.

[0069] Figure 3 A flowchart illustrating the workflow for obtaining a predetermined increase or decrease in opening degree in existing technologies. Detailed Implementation

[0070] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0071] For ease of understanding, the specific structure and operation of the present invention will be further described below with reference to the accompanying drawings:

[0072] The present invention mainly includes: a method for adjusting the electronic expansion valve in the initial stage of the start-up phase of a variable frequency air conditioning unit, a method for adjusting the electronic expansion valve in the operation phase of the operation phase of a variable frequency air conditioning unit, and a method for adjusting the electronic expansion valve in the closing phase of the shutdown phase of a variable frequency air conditioning unit.

[0073] in:

[0074] I. For example Figure 1 As shown, the adjustment method for the electronic expansion valve in the initial stage includes the following steps:

[0075] S1. Obtain the current ambient temperature and the current actual water temperature;

[0076] S2. Input the acquired ambient temperature and actual water temperature into the preset initial opening calculation model to obtain the initial opening value of the electronic expansion valve.

[0077] The initial opening calculation model is as follows:

[0078] P EXVE1 =EXV1+(T wJ -T w )*N+(T a -T aJ )*M

[0079] In the formula: R EXVE1 This represents the initial opening value of the electronic expansion valve, in pls.

[0080] EXV1 is the rated opening, in pls;

[0081] T wJ The water temperature is the baseline, and the unit is °C.

[0082] T win The actual current water temperature, in °C;

[0083] T a The current ambient temperature is expressed in °C.

[0084] T aJ The ambient temperature is the baseline, and the unit is °C.

[0085] N is the water temperature influence coefficient;

[0086] M is the environmental temperature influence coefficient;

[0087] S3. Adjust the initial opening of the electronic expansion valve according to the obtained initial opening value.

[0088] In the above initial opening calculation model, the reference water temperature is 41℃ and the reference ambient temperature is 7℃.

[0089] Furthermore, at the current ambient temperature T a The values ​​of the environmental temperature influence coefficient M are shown in Table 1 below, and the values ​​of the rated opening EXV1 are shown in Table 3 below, for different ambient temperature reference values; at the current ambient temperature T a Under different ambient temperature comparison values ​​and the current actual water temperature T win The values ​​of the water temperature influence coefficient N are shown in Table 2 below for different water temperature control values.

[0090] Table 1: Values ​​of Ambient Temperature Influence Coefficient M

[0091]

[0092] Table 2: Values ​​of Water Temperature Influence Coefficient N

[0093]

[0094] Table 3: Values ​​of Rated Point Valve Opening EXV1

[0095]

[0096] In Tables 1-3 above, M1~M3, N1~N9, and P1~P3 are all obtained using interpolation.

[0097] Specifically, this interpolation method is existing technology. For ease of understanding, we will take the interpolation value of the ambient temperature influence coefficient M1 when the current ambient temperature is -25℃ as an example:

[0098] M1 = M value when the ambient temperature reference value is -30℃ + (current ambient temperature -25℃ - ambient temperature reference value -30℃) * (M value when the ambient temperature reference value is -20℃ - M value when the ambient temperature reference value is -30℃) / (ambient temperature reference value -20℃ - ambient temperature reference value -30℃)

[0099] =1.5 + (-25 + 30) * (2.1 - 1.5) / (-20 + 30)

[0100] =1.5 + 0.3

[0101] =1.8.

[0102] Similarly, the formula for calculating the water temperature influence coefficient N is to first determine the range of the water temperature influence coefficient N by using the current ambient temperature and the current actual water temperature. For example, when the ambient temperature is 25℃ and the water temperature is 35℃, the value of the water temperature influence coefficient N is N8. The solution is similar to the interpolation method mentioned above, except that the water temperature reference value is used as the solution reference for the interpolation method to solve the value of N8.

[0103] N8 = N value when the water temperature reference value is 30℃ + (current actual water temperature 35℃ - water temperature reference value 30℃) * (N value when the water temperature reference value is 45℃ - N value when the water temperature reference value is 30℃) / (water temperature reference value 45℃ - water temperature reference value 30℃)

[0104] =4.5 + (35 - 30) * (3.5 - 4.5) / (45 - 30)

[0105] ≈4.17.

[0106] To verify the application effect of the electronic expansion valve at the initial opening obtained from the above calculation model:

[0107] In Practice 1, under the operating conditions of an ambient temperature of -12℃ and an actual water temperature of 41℃, the initial opening degree of the electronic expansion valve, calculated according to the initial opening degree calculation model, is 147pls.

[0108] During the test, under the above operating conditions, after the unit was started, the electronic expansion valve was adjusted to different opening degrees, and then subsequent adjustments were made according to the conventional adjustment method under normal conditions (not the adjustment method for the operating stage described later in this application; a comparison between the specific conventional adjustment and the adjustment for the operating stage of this application will be made later). The results are as follows:

[0109] After the unit is started, the electronic expansion valve starts to adjust after maintaining an initial opening of 170pls. After 28 minutes, when the system is running stably (the valve opening remains unchanged), the valve step finally stabilizes at 160pls.

[0110] After the unit is started, the electronic expansion valve begins to adjust after maintaining an initial opening of 147 pls. After 25 minutes, once the system is running stably (with the valve opening remaining unchanged), the valve step eventually stabilizes at 160 pls.

[0111] After the unit is started, the electronic expansion valve starts to adjust after maintaining an initial opening of 130 pls. After 27 minutes, when the system is running stably (the valve opening remains unchanged), the valve step finally stabilizes at 160 pls.

[0112] In Practice 2, under the operating conditions of an ambient temperature of -12℃ and an actual water temperature of 55℃, the initial opening degree of the electronic expansion valve, calculated according to the initial opening degree calculation model, is 119pls.

[0113] During the test, under the above operating conditions, after the unit was started, the electronic expansion valve was adjusted to different opening degrees, and subsequent adjustments were made according to the conventional adjustment method under normal conditions. The results are as follows:

[0114] After the unit is started, the electronic expansion valve starts to adjust after maintaining an initial opening of 150 pls. After 29 minutes, when the system is running stably (with the valve opening remaining unchanged), the valve step finally stabilizes at 135 pls.

[0115] After the unit is started, the electronic expansion valve starts to adjust after maintaining an initial opening of 119 pls. After 27 minutes, after the system is running stably (the valve opening remains unchanged), the valve step finally stabilizes at 135 pls.

[0116] After the unit is started, the electronic expansion valve starts to adjust after maintaining an initial opening of 110 pls. After 45 minutes, after the system is running stably (the valve opening remains unchanged), the valve step is too small to meet the defrosting adjustment, which leads to defrosting. After defrosting, the valve is readjusted. After a total of 45 minutes from start-up to stabilization, the system is running stably (the valve opening remains unchanged), and the valve step finally stabilizes at 135 pls.

[0117] Clearly, the results of Practice 1 and Practice 2 above show that, for normal regulation under normal conditions, different initial openings of the electronic expansion valve result in different stabilization times. Furthermore, when the initial opening of the electronic expansion valve is close to the initial opening calculated by the aforementioned initial opening calculation model, the time required from start-up to system stabilization is the shortest. This also proves that opening the electronic expansion valve according to the initial opening calculation model obtained in this application can reduce the regulation time during the process from unit start-up to system stabilization, avoid regulation lag caused by fixed opening, shorten the time from system start-up to stabilization, thereby ensuring rapid response and stable operation under extreme conditions such as high-temperature cooling and low-temperature heating, and overcoming the limitations of traditional fixed opening control.

[0118] The adjustment method for the operation phase applies the adjustment method used for the initial stage of the electronic expansion valve.

[0119] The existing adjustment method is as follows: after the unit starts up, the initial opening value is maintained for a fixed adjustment cycle, and the compressor's discharge temperature T is continuously acquired. d 1. Compressor fin temperature T def The superheat of the compressor's exhaust gas, T dsh and the current opening value P of the electronic expansion valve iBefore each fixed adjustment cycle of the subsequent electronic expansion valve, a predetermined increase or decrease in the opening degree of the electronic expansion valve is generated according to a conventional adjustment strategy. This conventional adjustment strategy generates the predetermined increase or decrease in the opening degree of the electronic expansion valve, and its adjustment strategy is as follows: Figure 3 As shown, this part is a conventional strategy in the prior art. This application does not elaborate on the detailed PID calculation process of the electronic expansion valve adjustment value, but only further controls it based on the calculated result of the predetermined opening degree increase or decrease.

[0120] Based on the above, before each subsequent fixed adjustment cycle, first determine T. d and T dsh If the range is abnormal, adjust the electronic expansion valve according to the exhaust anomaly strategy and the superheat anomaly strategy, respectively, to prevent the unit from running out of control due to excessively high exhaust temperature and to protect the compressor; if not, then determine T. def Is it an abnormal interval? If T def If it falls within the abnormal range, adjust the electronic expansion valve according to the fin abnormality strategy to prevent the electronic expansion valve from undergoing defrosting due to excessively low fin temperature caused by inaccurate traditional PID calculation and adjustment; if T def If it is not in an abnormal range, the electronic expansion valve is adjusted according to the optimized adjustment strategy. In addition, if the compressor frequency changes within each fixed adjustment cycle, the frequency opening increase or decrease is generated according to the conventional frequency adjustment strategy, and the opening of the electronic expansion valve is adjusted according to the frequency opening increase or decrease before each fixed adjustment cycle.

[0121] This application employs a tiered approach to assessing abnormal conditions. It prioritizes addressing exhaust superheat anomalies that could lead to uncontrolled exhaust temperature or compressor damage, ensuring system safety. Next, it addresses fin temperature anomalies to prevent accidental defrosting. In the absence of anomalies, an optimized adjustment strategy is used to achieve precise and stable operational control. Overall, it balances safety, prevention of misoperation, and energy efficiency optimization.

[0122] Based on the above, such as Figure 2 As shown, the optimization and adjustment strategy is as follows: obtain the cumulative continuous increase or decrease of several previous fixed adjustment cycles, and obtain the exhaust temperature difference between the end of the previous fixed adjustment cycle and the beginning of the previous fixed adjustment cycle; then, first determine the current opening value P of the electronic expansion valve. i The system determines whether the cumulative continuous decrease or increase in temperature exceeds the corresponding decrease or increase threshold of the set range. If it does not exceed the threshold, the electronic expansion valve is adjusted directly according to the predetermined opening increment or decrement, which is the traditional method of adjusting the electronic expansion valve according to the predetermined opening increment or decrement.

[0123] In the initial fixed adjustment cycle, the opening of the electronic expansion valve is reduced to increase the rate of increase in exhaust temperature. If the reduction threshold is exceeded, in subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing only the predetermined opening adjustment operation. This prevents the cumulative continuous reduction of the electronic expansion valve in adjacent cycles from further expanding, which would lead to an excessive rate of increase in exhaust temperature in subsequent fixed adjustment cycles. This ensures that the exhaust temperature is within a reasonable and stable fluctuation range, avoids repeated adjustments of the electronic expansion valve, and allows the system to enter a stable operating phase more quickly.

[0124] In the initial fixed adjustment cycle, the electronic expansion valve's opening is increased to reduce the rate of increase in exhaust temperature. If the increase threshold is exceeded, the exhaust temperature difference is further checked to see if it exceeds the temperature rise threshold. If it does, it indicates that the exhaust temperature rise rate is still too high. Therefore, in subsequent fixed adjustment cycles, the electronic expansion valve is limited to opening only by a predetermined opening increment / decrement to further reduce the exhaust temperature rise rate. If it does not exceed the threshold, it indicates that the exhaust temperature rise rate is adjusted too low. In subsequent fixed adjustment cycles, the electronic expansion valve is limited to closing only by a predetermined opening increment / decrement to ensure that the exhaust temperature remains within a reasonable and stable fluctuation range, avoiding repeated adjustments of the electronic expansion valve and allowing the system to enter a stable operating phase more quickly.

[0125] Based on the above, the strategy is optimized and adjusted as follows:

[0126] When P i When the temperature difference is greater than 240 pls, the exhaust temperature difference of the previous fixed adjustment cycle is within the full range, and the reduction threshold is 8% of the current opening; the increase threshold is 6% of the current opening.

[0127] When 160pls≤P i When the exhaust temperature difference is ≤240pls, the exhaust temperature difference of the previous fixed adjustment cycle is within the full range, and the reduction threshold is 6% of the current opening degree; when the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 4℃, the increase threshold is 5% of the current opening degree; when the exhaust temperature difference of the previous fixed adjustment cycle is greater than 4℃, the increase threshold is 4% of the current opening degree.

[0128] When P iWhen the temperature difference is less than 160 pls, if the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 1℃, the reduction threshold is 6% of the current opening; if the temperature increase of the previous fixed adjustment cycle is greater than 1℃, the reduction threshold is 5% of the current opening. If the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 1.5℃, the increase threshold is 5% of the current opening; if the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 2.5℃ and greater than or equal to 1.5℃, the increase threshold is 4% of the current opening; if the exhaust temperature difference of the previous fixed adjustment cycle is greater than 2.5℃, the increase threshold is 3% of the current opening.

[0129] Because a larger opening degree of the electronic expansion valve results in a larger medium flow rate, and consequently a greater range of changes in the exhaust temperature, this application specifies the current opening degree P of the electronic expansion valve. i The values ​​are set to high, medium, and low, and the exhaust temperature difference is also set to high, medium, and low. The current opening value P of the electronic expansion valve is also specified. i When the difference between the exhaust temperature and the exhaust temperature is in different ranges, optimize the difference in the increase or decrease threshold to ensure that the exhaust temperature fluctuation is more stable, so that the system can enter the stable operation stage more quickly.

[0130] Based on the above, the strategy is optimized and adjusted as follows:

[0131] When P i >240pls, and the electronic expansion valve opening was decreasing in the previous fixed adjustment cycle:

[0132] If the exhaust temperature difference is less than or equal to 2℃, then in a subsequent fixed adjustment cycle, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0133] If the exhaust temperature difference is greater than 2℃ and less than or equal to 4℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0134] If the exhaust temperature difference is greater than 4℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve will be limited to performing adjustment operations with a predetermined opening degree increase or decrease of only the valve opening range.

[0135] When P i >240pls, and the electronic expansion valve opening was increasing in the previous fixed adjustment cycle:

[0136] The temperature rise threshold at this time is 2℃. If the exhaust temperature difference is less than or equal to 2℃, then in the next two fixed cycles, the electronic expansion valve is limited to performing the predetermined opening increase or decrease range adjustment operation of closing the valve.

[0137] If the exhaust temperature difference is greater than 2℃ and less than or equal to 5℃, then in a subsequent fixed cycle, the electronic expansion valve is limited to performing only the predetermined opening adjustment operation.

[0138] If the exhaust temperature difference is greater than 5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increase or decrease range of opening the valve.

[0139] When 160pls≤P i ≤240pls, and the opening of the electronic expansion valve was decreasing in the previous fixed adjustment cycle;

[0140] If the exhaust temperature difference is less than or equal to 2℃, then in a subsequent fixed adjustment cycle, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0141] If the exhaust temperature difference is greater than 2℃ and less than or equal to 3℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0142] If the exhaust temperature difference is greater than 3℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening degree increase or decrease range of opening the valve.

[0143] When 160pls≤P i ≤240pls, and the electronic expansion valve opening was increasing in the previous fixed adjustment cycle;

[0144] The temperature rise threshold at this time is 1.5℃. If the exhaust temperature difference is less than or equal to 1.5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing the adjustment operation of closing the valve only by the predetermined opening increase or decrease range.

[0145] If the exhaust temperature difference is greater than 1.5℃ and less than or equal to 4℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0146] If the exhaust temperature difference is greater than 4℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increase or decrease range of opening the valve.

[0147] When P i <160pls, and the electronic expansion valve opening was decreasing in the previous fixed adjustment cycle:

[0148] If the exhaust temperature difference is less than or equal to 1℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0149] If the exhaust temperature difference is greater than 1℃ and less than or equal to 2.5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening degree increase or decrease of only the valve opening range.

[0150] If the exhaust temperature difference is greater than 2.5℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening degree increase or decrease range of opening the valve.

[0151] When P i <160pls, and the electronic expansion valve opening was increasing in the previous fixed adjustment cycle:

[0152] The temperature rise threshold at this time is 1.5℃. If the exhaust temperature difference is less than or equal to 1.5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing the adjustment operation of closing the valve only by the predetermined opening increase or decrease range.

[0153] If the exhaust temperature difference is greater than 1.5℃ and less than or equal to 2.5℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening.

[0154] If the exhaust temperature difference is greater than 2.5℃, then in the subsequent two fixed adjustment cycles, if the predetermined opening increment or decrement is equal to the valve opening increment, the electronic expansion valve is limited to performing adjustment operations with the predetermined opening increment or decrement being equal to the valve opening.

[0155] This application will specify the current opening value P of the electronic expansion valve. i The values ​​are set to high, medium, and low, and the exhaust temperature difference is also set to high, medium, and low. The current opening value P of the electronic expansion valve is also specified. i When the temperature difference between the exhaust and the exhaust is within a different range, the number of cycles is further limited to ensure that the exhaust temperature fluctuations are more stable, so that the system can enter a stable operating phase more quickly.

[0156] In practice, under the conditions of an ambient temperature of -12℃ and an outlet water temperature of 41℃,

[0157] Controlled according to the optimization and adjustment strategy of this application:

[0158] After startup, the initial opening of the electronic expansion valve is 147 pls. After 20 minutes, the unit stabilizes at 160 pls. The minimum valve step during operation is 135 pls, and the maximum valve step is 175 pls.

[0159] However, without the aforementioned optimization and adjustment strategies:

[0160] After startup, the initial opening of the electronic expansion valve is 147 pls. After 25 minutes, the unit stabilizes at 160 pls. The minimum valve step during operation is 120 pls, and the maximum valve step is 180 pls.

[0161] Based on the valve step operation data above, using the above-mentioned optimization and adjustment strategy, the unit requires less time to achieve stable operation, the valve step adjustment is more stable, and the fluctuation range is smaller.

[0162] Based on the above, the execution condition for the overheating anomaly strategy is T. dsh Minimum exhaust superheat T dshmin In actual implementation, to meet the compressor reliability requirements, the minimum exhaust superheat T dshmin Generally, a value not lower than 15℃ is sufficient to meet the minimum oil temperature superheat requirement. Of course, under different refrigerant requirements, the minimum exhaust superheat T will vary. dshmin The values ​​may vary; set them according to the actual requirements of the compressor. The specific exhaust anomaly strategy is as follows: In subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations where the valve is closed only after a predetermined opening increase or decrease range, until T... dsh ≥Minimum exhaust superheat T dshmin This conventional frequency regulation strategy is an existing technology. The increase or decrease in frequency opening is obtained by multiplying the frequency change value by the valve step adjustment coefficient. This regulation method prevents the exhaust superheat value from becoming too low, effectively protecting the compressor.

[0163] The execution condition for the exhaust anomaly strategy is T. d For temperatures ≥105℃, the specific exhaust abnormality strategy is as follows: Obtain the first opening value of the electronic expansion valve at this time. In subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening until the exhaust temperature drops and the exhaust temperature is <100℃. At this time, the second opening value of the electronic expansion valve is obtained, and the difference between the second opening value and the first opening value is obtained. In subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve closing until the cumulative decrease of the electronic expansion valve in this stage is greater than or equal to 0.4 times the difference in the increase or decrease. Two fixed adjustment cycles of the electronic expansion valve are taken as one actual adjustment cycle. After three actual adjustment cycles, the fixed adjustment cycle is restored.

[0164] In practice, under operating conditions of an ambient temperature of -25℃ and an outlet water temperature of 50℃, the following are comparisons of adjusting the opening of the electronic expansion valve according to the abnormal exhaust temperature strategy of this application and adjusting the opening of the electronic expansion valve according to the conventional adjustment strategy:

[0165] When implementing the exhaust anomaly strategy, if the exhaust temperature Td ≥ 105℃, and the predetermined opening increment / decrement of the electronic expansion valve is +20pls, +15pls, and +15pls in the subsequent three fixed adjustment cycles, the difference in opening is 50pls. A 0.4 times difference in opening is 20pls. When valve closure is detected (i.e., exhaust temperature decrease), and the predetermined opening increment / decrement is -15pls and -10pls in the subsequent two fixed adjustment cycles, closing the valve twice according to this predetermined opening increment / decrement satisfies the requirement that the cumulative decrease in electronic expansion valve opening of 25pls is greater than 0.4 times the difference in opening. Afterward, the valve is closed once every 2*TM cycles, with three consecutive actual adjustment cycles showing valve closure increments of 7pls, 5pls, and 3pls, before resuming the fixed adjustment cycle. At this point, T... d <105℃;

[0166] Without adopting the above-mentioned exhaust anomaly strategy, when the exhaust temperature Td ≥ 105℃, the predetermined opening increment / decrement of the electronic expansion valve in the subsequent three fixed adjustment cycles is +20pls, +15pls, and +15pls. When the need to close the valve is detected, i.e., when the exhaust temperature decreases, in the subsequent adjustment cycles, the valve is closed continuously for -15pls, -10pls, -10pls, -10pls, and -9pls respectively. Then, when the exhaust temperature Td ≥ 105℃ again, the valve opening increment is +20pls, +15pls, and +13pls, repeatedly triggering excessively high exhaust temperatures and resulting in unstable operation.

[0167] Compared with the above actual operating conditions, when the exhaust temperature changes drastically, it is easier to control the unit's stable operation by adopting an exhaust anomaly strategy logic control.

[0168] The execution condition for the fin anomaly strategy is T. def <Target fin temperature at the start of defrosting +2℃. The specific fin anomaly strategy is as follows: In subsequent fixed adjustment cycles, the electronic expansion valve is limited to adjusting only by a predetermined opening increment / decrement, and the opening increment / decrement is 1.5 times the predetermined opening increment / decrement, until T... def ≥Target fin temperature at the start of defrosting + 2℃, at the compressor fin temperature T def If the temperature is about to fall below the target fin temperature for defrosting, increasing the opening of the electronic expansion valve can prevent the electronic expansion valve from defrosting due to the inaccuracy of traditional PID calculation and adjustment.

[0169] The adjustment method for the shutdown phase applies the same method as during operation. When the compressor receives a shutdown command, the electronic expansion valve maintains its current opening. After the compressor shuts down to 0Hz, the electronic expansion valve opening is adjusted to 80pls and maintained for 120 seconds. Then, the opening is adjusted to 200pls until the next startup command is received, at which point the initial opening of the electronic expansion valve is adjusted according to the initial opening method. This adjustment method prevents the electronic expansion valve from opening too wide immediately after shutdown, which would cause a large amount of refrigerant to flow to the low-pressure side, resulting in a sudden vaporization of the refrigerant on the low-pressure side upon restarting, carrying away a large amount of refrigeration oil and causing oil shortage.

[0170] Of course, those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0171] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0172] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A method for adjusting an electronic expansion valve during its initial and operational phases, characterized in that, Includes the following steps: S1. Obtain the current ambient temperature and the current actual water temperature; S2. Input the acquired ambient temperature and actual water temperature into the preset initial opening calculation model to obtain the initial opening value of the electronic expansion valve. The initial opening calculation model is as follows: In the formula: This represents the initial opening value of the electronic expansion valve, in pls. This is the rated opening, measured in pls. The water temperature is the baseline, and the unit is °C. The actual current water temperature, in °C; The current ambient temperature is expressed in °C. The ambient temperature is the baseline, and the unit is °C. This is the water temperature influence coefficient; The environmental temperature influence coefficient; S3. Adjust the initial opening of the electronic expansion valve according to the obtained initial opening value; After the unit starts up, maintain the initial opening value for one fixed adjustment cycle; continuously acquire the compressor's discharge temperature. Outdoor heat exchanger fin temperature compressor exhaust superheat and the current opening value of the electronic expansion valve And before each fixed adjustment cycle of the subsequent electronic expansion valve, the predetermined opening increase or decrease range of the electronic expansion valve is generated according to the conventional adjustment strategy; Before each subsequent fixed adjustment cycle, first determine and If the range is abnormal, adjust the electronic expansion valve according to the exhaust anomaly strategy and the superheat anomaly strategy respectively; otherwise, determine the next step. Is it an abnormal range? If it is in an abnormal range, adjust the electronic expansion valve according to the fin abnormality strategy; if If it is not in an abnormal range, adjust the electronic expansion valve according to the optimization and adjustment strategy; In addition, if the compressor frequency changes within each fixed adjustment cycle, the frequency opening increment or decrement is generated according to the conventional frequency adjustment strategy, and the opening of the electronic expansion valve is adjusted according to the frequency opening increment or decrement before each fixed adjustment cycle.

2. The adjustment method for the electronic expansion valve in the initial and operational stages according to claim 1, characterized in that, The optimization and adjustment strategy specifically involves: obtaining the cumulative continuous increase or decrease over several previous fixed adjustment cycles, and obtaining the exhaust temperature difference between the end of the previous fixed adjustment cycle and the beginning of the previous fixed adjustment cycle; subsequently, determining the current opening value of the electronic expansion valve. The system determines whether the cumulative continuous decrease or increase in temperature exceeds the corresponding decrease or increase threshold of the set range. If it does not exceed the threshold, the electronic expansion valve is adjusted directly according to the predetermined opening degree. If the decrease threshold is exceeded, the electronic expansion valve will be limited to opening the valve for several fixed adjustment cycles. If the increase threshold is exceeded, it will be further determined whether the exhaust temperature difference exceeds the temperature increase threshold. If it does, the electronic expansion valve will be limited to opening the valve for several fixed adjustment cycles. If it does not exceed the threshold, the electronic expansion valve will be limited to closing the valve for several fixed adjustment cycles.

3. The adjustment method for the electronic expansion valve in the initial and operational stages according to claim 2, characterized in that, In the aforementioned optimization and adjustment strategy: when When the temperature difference is greater than 240 pls, the exhaust temperature difference of the previous fixed adjustment cycle is within the full range, and the reduction threshold is 8% of the current opening; the increase threshold is 6% of the current opening. When 160pls≤ When the exhaust temperature difference is ≤240pls, the exhaust temperature difference of the previous fixed adjustment cycle is within the full range, and the reduction threshold is 6% of the current opening. When the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 4℃, the increase threshold is 5% of the current opening. When the exhaust temperature difference of the previous fixed adjustment cycle is greater than 4℃, the increase threshold is 4% of the current opening. when When the temperature difference is less than 160 pls, if the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 1℃, the reduction threshold is 6% of the current opening; if the temperature increase of the previous fixed adjustment cycle is greater than 1℃, the reduction threshold is 5% of the current opening. If the exhaust temperature difference of the previous fixed adjustment cycle is less than 1.5℃, the increase threshold is 5% of the current opening; if the exhaust temperature difference of the previous fixed adjustment cycle is less than or equal to 2.5℃ and greater than or equal to 1.5℃, the increase threshold is 4% of the current opening; if the exhaust temperature difference of the previous fixed adjustment cycle is greater than 2.5℃, the increase threshold is 3% of the current opening.

4. The adjustment method for the electronic expansion valve in the initial and operational stages according to claim 2, characterized in that, In the aforementioned optimization and adjustment strategy: when >240pls, and the electronic expansion valve opening was decreasing in the previous fixed adjustment cycle: If the exhaust temperature difference is less than or equal to 2℃, then in a subsequent fixed adjustment cycle, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening. If the exhaust temperature difference is greater than 2℃ and less than or equal to 4℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening. If the exhaust temperature difference is greater than 4℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve will be limited to performing adjustment operations with a predetermined opening degree increase or decrease of only the valve opening range. when >240pls, and the electronic expansion valve opening was increasing in the previous fixed adjustment cycle: The temperature rise threshold at this time is 2℃. If the exhaust temperature difference is less than or equal to 2℃, then in the next two fixed cycles, the electronic expansion valve is limited to performing the predetermined opening increase or decrease range adjustment operation of closing the valve. If the exhaust temperature difference is greater than 2℃ and less than or equal to 5℃, then in a subsequent fixed cycle, the electronic expansion valve is limited to performing only the predetermined opening adjustment operation. If the exhaust temperature difference is greater than 5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increase or decrease range of opening the valve. When 160pls≤ ≤240pls, and the opening of the electronic expansion valve was decreasing in the previous fixed adjustment cycle; If the exhaust temperature difference is less than or equal to 2℃, then in a subsequent fixed adjustment cycle, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening. If the exhaust temperature difference is greater than 2℃ and less than or equal to 3℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening. If the exhaust temperature difference is greater than 3℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening degree increase or decrease range of opening the valve. When 160pls≤ ≤240pls, and the electronic expansion valve opening was increasing in the previous fixed adjustment cycle; The temperature rise threshold at this time is 1.5℃. If the exhaust temperature difference is less than or equal to 1.5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing the adjustment operation of closing the valve only by the predetermined opening increase or decrease range. If the exhaust temperature difference is greater than 1.5℃ and less than or equal to 4℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening. If the exhaust temperature difference is greater than 4℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increase or decrease range of opening the valve. when <160pls, and the electronic expansion valve opening was decreasing in the previous fixed adjustment cycle: If the exhaust temperature difference is less than or equal to 1℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening. If the exhaust temperature difference is greater than 1℃ and less than or equal to 2.5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening degree increase or decrease of only the valve opening range. If the exhaust temperature difference is greater than 2.5℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening degree increase or decrease range of opening the valve. when <160pls, and the electronic expansion valve opening was increasing in the previous fixed adjustment cycle: The temperature rise threshold at this time is 1.5℃. If the exhaust temperature difference is less than or equal to 1.5℃, then in the subsequent two fixed adjustment cycles, the electronic expansion valve is limited to performing the adjustment operation of closing the valve only by the predetermined opening increase or decrease range. If the exhaust temperature difference is greater than 1.5℃ and less than or equal to 2.5℃, then in the subsequent three fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increment or decrement of the valve opening. If the exhaust temperature difference is greater than 2.5℃, then in the subsequent two fixed adjustment cycles, if the predetermined opening increment or decrement is equal to the valve opening increment, the electronic expansion valve is limited to performing adjustment operations with the predetermined opening increment or decrement being equal to the valve opening.

5. The adjustment method for the electronic expansion valve in the initial and operational stages according to claim 1, characterized in that, The execution conditions for the superheat anomaly strategy are as follows: Minimum exhaust superheat The specific superheat anomaly strategy is as follows: In subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations where the valve is closed only if the predetermined opening increase or decrease range is reached, until... ≥Minimum exhaust superheat .

6. The adjustment method for the electronic expansion valve in the initial and operational stages according to claim 1, characterized in that, The execution conditions for the exhaust anomaly strategy are as follows: For temperatures ≥105℃, the specific exhaust abnormality strategy is as follows: Obtain the first opening value of the electronic expansion valve at this time. In subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increase or decrease of the valve opening range until the exhaust temperature drops and the exhaust temperature is <100℃. At this time, the second opening value of the electronic expansion valve is obtained, and the difference between the second opening value and the first opening value is obtained. In subsequent fixed adjustment cycles, the electronic expansion valve is limited to performing adjustment operations with a predetermined opening increase or decrease of the valve closing range until the cumulative decrease of the electronic expansion valve in this stage is greater than or equal to 0.4 times the aforementioned difference. Two fixed adjustment cycles of the electronic expansion valve are taken as one actual adjustment cycle. After three actual adjustment cycles, the fixed adjustment cycle is restored.

7. The adjustment method for the electronic expansion valve in the initial and operational stages according to claim 1, characterized in that, The execution conditions for the fin anomaly strategy are as follows: <Target fin temperature at the start of defrosting +2℃. The specific fin anomaly strategy is as follows: In subsequent fixed adjustment cycles, the electronic expansion valve is limited to adjusting only by a predetermined opening increment / decrement, and the opening increment / decrement is 1.5 times the predetermined opening increment / decrement, until... ≥Target fin temperature at the start of defrosting +2℃.

8. A method for adjusting the shut-off phase, wherein the method for adjusting the shut-off phase applies the method for adjusting the initial and operational phases of an electronic expansion valve as described in any one of claims 1-6, characterized in that, When the compressor receives a shutdown command, the electronic expansion valve maintains its current opening. After the compressor shuts down to a frequency of 0Hz, the opening of the electronic expansion valve is adjusted to 80pls and held for 120 seconds. After that, the opening of the electronic expansion valve is adjusted to 200pls. The initial opening of the electronic expansion valve is adjusted according to the initial opening adjustment method of the electronic expansion valve after the next start-up adjustment command is received.

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