An electronic expansion valve adaptive superheat control method

Abstract

The application discloses an adaptive superheat control method of an electronic expansion valve, which realizes accurate control of superheat of a heat pump system in all working conditions through the synergistic effect of superheat calculation through multi-sensor fusion, dynamic target superheat generation, segmented asymmetric proportional regulation and feedforward compensation. In the method, exhaust temperature and return air and coil temperature are weighted and fused, the weight is adaptively switched according to the sensor state, fault tolerance robustness is improved, multi-dimensional information such as operation mode, ambient temperature and compressor start is fused to dynamically generate a target superheat, the target superheat is adapted to variable working condition requirements, then an asymmetric regulation strategy with a gain in the under-heat area being greater than that in the over-heat area is adopted to preferentially inhibit the risk of liquid hammer and avoid oscillation, and finally, feedforward compensation is superimposed on disturbances such as compressor start and stop and defrosting switching to shorten the recovery time. The scheme can guarantee the safe operation of the compressor and the energy efficiency of the system.

Description

Technical Field

[0001] This invention relates to the field of intelligent control technology for heat pump systems, and in particular to an adaptive overheat control method for an electronic expansion valve. Background Technology

[0002] Air source heat pump systems, with their advantages of high efficiency, energy saving, and dual heating and cooling capabilities, have been widely used in high-precision constant temperature control scenarios such as mushroom cultivation cabins. These scenarios have extremely high requirements for temperature control accuracy and operational reliability. The system needs to frequently switch between heating and cooling modes and is affected by factors such as day-night temperature differences and the linkage between fresh air and dehumidification, resulting in drastic fluctuations in operating conditions.

[0003] The electronic expansion valve is the core actuator for regulating refrigerant flow in a heat pump system. It adjusts the evaporator superheat (SH) by controlling the valve opening. The accuracy of superheat control directly determines the compressor's operational safety and system energy efficiency. If it is too low, it can easily cause liquid slugging and damage the compressor; if it is too high, energy efficiency will decrease, exhaust temperature will exceed the limit, and aging will be accelerated.

[0004] Currently, the mainstream control methods for electronic expansion valves in the industry mainly rely on fixed-parameter PID control and lookup table methods, calculating superheat solely based on return gas temperature and coil temperature, and using a fixed target value for feedback regulation. For variable operating condition control requirements, existing technologies mainly focus on two improvement directions: one is to correct the target superheat by introducing ambient temperature and load-side parameters, and the other is to suppress superheat measurement oscillations through filtering algorithms or model predictive control. However, the above solutions still have the following drawbacks in scenarios with frequent changing operating conditions, multiple disturbances, and high reliability requirements:

[0005] First, the sensing layer lacks fault tolerance. The superheat calculation relies solely on two sensors: the return gas sensor and the coil sensor. It does not integrate system operating parameters such as exhaust temperature for cross-validation and weighted fusion. When any sensor fails, the calculation results are directly distorted, and there is no automatic degradation mechanism, making it difficult to meet the reliability requirements for long-term continuous operation.

[0006] Second, the target superheat adaptation dimensions are limited. Existing dynamic target superheat solutions are mostly based on indoor cooling load correction, and do not adapt to typical operating conditions such as heating / cooling mode switching, low ambient temperature operation, and compressor start-up shock, resulting in a low degree of matching between the target value and the actual operating state.

[0007] Third, the adjustment strategies do not differentiate between safety priorities and lack dead zones. Existing solutions mostly use symmetrical adjustment parameters, failing to distinguish between the safety priorities of underheating (liquid slugging risk) and overheating (energy efficiency reduction). At the same time, most solutions lack adjustment dead zones, and even minor measurement fluctuations can trigger frequent valve actions, shortening the lifespan of the stepper motor.

[0008] Fourth, the control layer lacks an active disturbance rejection mechanism. Existing controls are all pure feedback regulation, which only passively corrects after the superheat deviation occurs. For predictable system disturbances such as compressor start-up and shutdown, four-way valve reversal for defrosting, and fan start-up and shutdown, there is no feedforward compensation in advance, resulting in a long recovery period after the disturbance. Summary of the Invention

[0009] In view of the above background technology, the present invention proposes an adaptive overheat control method for electronic expansion valves, which aims to solve the technical problems of insufficient fault tolerance of the sensing layer, poor adaptation to target overheat conditions, lack of safety priority distinction in the adjustment strategy, and lack of feedforward anti-disturbance mechanism in the existing overheat control.

[0010] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0011] An adaptive overheat control method for an electronic expansion valve includes the following steps:

[0012] Real-time acquisition of evaporator return gas temperature, evaporator coil temperature, compressor discharge temperature, outdoor ambient temperature, and cabin ambient temperature;

[0013] The basic superheat is calculated based on the evaporator return gas temperature and the evaporator coil temperature. A benchmark target exhaust temperature is preset according to the current operating mode. The exhaust correction is calculated using the benchmark target exhaust temperature and the compressor exhaust temperature. The weighting weights corresponding to the basic superheat and the exhaust correction are configured according to the detection status of each temperature sensor. The control superheat is obtained after weighted fusion.

[0014] The correction values ​​corresponding to the operating mode, outdoor ambient temperature and compressor running time are obtained respectively. Based on the preset reference superheat, the correction values ​​are superimposed on the preset reference superheat, and the dynamic target superheat is obtained after upper and lower limit processing.

[0015] Calculate the deviation between the control superheat and the dynamic target superheat, and match the corresponding asymmetric adjustment gain according to the underheating or overheating range where the deviation is located. The adjustment gain matched in the underheating range is greater than the adjustment gain matched in the overheating range. The basic opening adjustment amount is calculated using the matched adjustment gain.

[0016] Identify preset operating condition disturbance events, match the corresponding feedforward compensation opening degree according to the type of the operating condition disturbance event, wherein the direction and / or amplitude of the feedforward compensation opening degree corresponding to different types of operating condition disturbance events are different, and the feedforward compensation opening degree is superimposed on the basic opening degree adjustment amount to obtain the total opening degree adjustment amount.

[0017] The total opening adjustment amount is used to generate an electronic expansion valve drive signal to control the electronic expansion valve to adjust the valve opening.

[0018] In some implementations, the weighting of the baseline superheat and the exhaust correction is set as follows:

[0019] When the return gas temperature sensor, evaporator coil temperature sensor, and exhaust temperature sensor are all normal, the weight of the base superheat is 0.7, and the weight of the exhaust correction is 0.3.

[0020] When the exhaust temperature sensor fails, the weight of the exhaust correction is reset to 0, and the weight of the base superheat is reset to 1.

[0021] When the evaporator coil temperature sensor fails, the weighted fusion is stopped and the system enters a degraded operation mode.

[0022] In some implementations, the method for determining the correction amount includes:

[0023] The correction value is +1℃ when the operating mode is heating mode, -0.5℃ when it is cooling mode, and 0℃ when it is constant temperature mode.

[0024] When the outdoor ambient temperature is ≤5℃, the corresponding correction is +2℃; when 5℃ < outdoor ambient temperature ≤10℃, the corresponding correction is +1℃; when the outdoor ambient temperature >10℃, the corresponding correction is 0℃.

[0025] The correction amount for the compressor running time is ΔTSH_start = 2×(1 - t_run / 180), where t_run is the cumulative number of seconds the compressor runs, and the correction amount is valid for 180 seconds after the compressor starts.

[0026] In some implementations, the upper and lower limit processing is to limit the dynamic target superheat to a range of 2°C to 12°C.

[0027] In some embodiments, matching the corresponding asymmetric adjustment gain according to the underheating or overheating range where the deviation is located includes:

[0028] When the deviation e ≤ -1℃, the matching adjustment gain Kp = 3;

[0029] When -1℃ < e ≤ 0℃, the matching adjustment gain Kp = 2;

[0030] When 0℃<e≤1℃, the matching adjustment gain Kp=1;

[0031] When e > 1℃, the matching adjustment gain Kp = 0.5.

[0032] In some embodiments, before calculating the base opening adjustment amount using the matched adjustment gain, the method further includes:

[0033] Determine whether the absolute value of the deviation is greater than a preset dead zone threshold. If yes, calculate the basic opening adjustment amount; otherwise, set the basic opening adjustment amount to zero.

[0034] In some implementations, the preset dead zone threshold is 0.3°C.

[0035] In some embodiments, the exhaust correction amount is:

[0036] SH_exh = α × (Td - Td_ref),

[0037] Wherein, Td is the compressor exhaust temperature, Td_ref is the reference target exhaust temperature, and α is the exhaust correction coefficient, with a value ranging from 0.1 to 0.3.

[0038] In some implementations, the preset operating condition disturbance events include compressor start-up, compressor shutdown, entering defrost mode, exiting defrost mode, outdoor fan start-up, outdoor fan shutdown, and exhaust fan start-up. The feedforward compensation settings corresponding to each operating condition disturbance event are as follows:

[0039] The compressor starts with +30 steps, which last for 3 seconds and then linearly decrease to 0.

[0040] The compressor stops in step -20, and returns to zero after 5 seconds.

[0041] Enter the corresponding +80 steps for defrosting, which will cover the entire defrosting process;

[0042] Exit defrost (step 80), and immediately reset to zero upon exit.

[0043] Starting the outdoor fan corresponds to +15 steps, and turning off the outdoor fan corresponds to -10 steps, both lasting for 10 seconds before decreasing.

[0044] Turning on the dehumidification fan requires 10 steps and remains effective during dehumidification operation.

[0045] In some implementations, the unit of the total opening adjustment is the number of steps, and each step of the electronic expansion valve corresponds to 0.1% of the valve opening.

[0046] The beneficial effects of this invention are as follows: Through the synergistic effect of multi-sensor fusion superheat calculation, dynamic target superheat generation, segmented asymmetric proportional adjustment, and feedforward compensation, precise superheat control of the heat pump system under all operating conditions is achieved. Specifically, a weighted fusion of exhaust temperature, return gas temperature, and coil temperature is introduced, with weights adaptively switching according to sensor status to improve fault tolerance and robustness. The target superheat is dynamically generated by fusing multi-dimensional information such as operating mode, ambient temperature, and compressor start-up to adapt to varying operating conditions. Then, an asymmetric adjustment strategy with a gain greater than that in the underheated zone is adopted to prioritize suppressing liquid slugging risk and avoid oscillations. Finally, feedforward compensation is superimposed to address disturbances such as compressor start-up / shutdown and defrosting switching, shortening recovery time. This solution ensures compressor operation safety and system energy efficiency. Attached Figure Description

[0047] Figure 1 This is a schematic flowchart of the adaptive overheat control method for electronic expansion valves disclosed in an embodiment of the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the content of this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to this invention are shown in the accompanying drawings, not all of them.

[0049] This embodiment proposes an adaptive overheat control method for electronic expansion valves, such as... Figure 1 As shown, it includes the following steps:

[0050] Step 1, Data Acquisition: Real-time acquisition of evaporator return gas temperature, evaporator coil temperature, compressor exhaust temperature, outdoor ambient temperature, and cabin ambient temperature.

[0051] In one example, the air source heat pump system used in this embodiment mainly includes a compressor, a four-way valve, an outdoor heat exchanger (condenser), an electronic expansion valve, an indoor heat exchanger (evaporator), and a gas-liquid separator. Each component is connected in sequence according to the heat pump system circulation loop.

[0052] The evaporator return gas temperature sensor is installed on the pipeline between the evaporator outlet and the compressor suction port to detect the refrigerant vapor temperature at the evaporator outlet; the evaporator coil temperature sensor is installed on the surface of the evaporator heat exchange coil to detect the evaporator coil wall temperature; the compressor discharge temperature sensor is installed on the pipeline between the compressor discharge port and the four-way valve to detect the compressor discharge temperature; the outdoor ambient temperature sensor is installed on the air inlet side of the outdoor heat exchanger to detect the outdoor ambient temperature; and the cabin ambient temperature sensor is installed at the return air vent inside the cabin to detect the cabin air temperature.

[0053] Step 2, Multi-sensor fusion superheat calculation: Calculate the basic superheat based on the evaporator return gas temperature and the evaporator coil temperature. Preset the benchmark target exhaust temperature according to the current operating mode. Calculate the exhaust correction amount using the benchmark target exhaust temperature and the compressor exhaust temperature. Configure the weighting weights corresponding to the basic superheat and the exhaust correction amount according to the detection status of each temperature sensor. After weighted fusion, the control superheat is obtained.

[0054] This step introduces exhaust temperature into the superheat weighted fusion, which can automatically switch weights when the exhaust sensor malfunctions, thus improving the fault tolerance and robustness of superheat measurement.

[0055] Specifically, the calculation method for the basic superheat is as follows: SH = T_S - T_E,

[0056] Where T_S is the evaporator return gas temperature and T_E is the evaporator coil temperature.

[0057] Specifically, in heating mode, the baseline target exhaust temperature Td_ref can be set to 85℃, and in cooling mode, Td_ref can be set to 75℃.

[0058] In one example, the exhaust correction is: SH_exh = α × (Td - Td_ref),

[0059] Where Td is the compressor exhaust temperature, Td_ref is the reference target exhaust temperature, and α is the exhaust correction coefficient, which ranges from 0.1 to 0.3, preferably α=0.15.

[0060] In this embodiment, the method for calculating the superheat is SH_ctrl = w1×SH + w2×SH_exh, where w1 is the weighted weight of the basic superheat and w2 is the weighted weight of the exhaust correction amount.

[0061] The weighting method for the base superheat and exhaust correction is as follows:

[0062] When the return gas temperature sensor, evaporator coil temperature sensor and exhaust temperature sensor are all normal, the weight w1 of the basic superheat is 0.7 and the weight w2 of the exhaust correction is 0.3.

[0063] When the exhaust temperature sensor fails, the weight w2 of the exhaust correction is set to 0, and the weight w1 of the base superheat is set to 1.

[0064] When the evaporator coil temperature sensor malfunctions, the baseline superheat (SH) becomes unavailable, weighted fusion stops, and the system enters a degraded operation mode. For example, the degraded operation mode may adjust to a fixed opening degree or based on exhaust temperature limits.

[0065] Step 3, Dynamic target superheat generation: Obtain the correction values ​​corresponding to the operating mode, outdoor ambient temperature and compressor running time respectively. Based on the preset benchmark superheat, add each correction value to the preset benchmark superheat, and obtain the dynamic target superheat after upper and lower limit processing.

[0066] In one example, the preset baseline superheat TSH_base = 5℃, which can be set to a range of 2℃ to 8℃.

[0067] The methods for determining the correction amount include:

[0068] When the operating mode is heating mode, the corresponding correction is +1℃, i.e., ΔTSH_mode = +1℃; when it is cooling mode, the corresponding correction is -0.5℃, i.e., ΔTSH_mode = -0.5℃; when it is constant temperature mode, the corresponding correction is 0℃, i.e., ΔTSH_mode = 0℃.

[0069] When the outdoor ambient temperature is ≤5℃, the corresponding correction is +2℃, i.e., ΔTSH_amb = +2℃; when 5℃ < outdoor ambient temperature ≤10℃, the corresponding correction is +1℃, i.e., ΔTSH_amb = +1℃; when the outdoor ambient temperature >10℃, the corresponding correction is 0℃, i.e., ΔTSH_amb = 0℃.

[0070] The correction amount for the compressor running time is ΔTSH_start = 2×(1 - t_run / 180), where t_run is the cumulative number of seconds the compressor runs. The correction amount is valid for 180 seconds after the compressor starts and then returns to zero.

[0071] Therefore, the dynamic target superheat TSH = TSH_base + ΔTSH_mode + ΔTSH_amb + ΔTSH_start. The upper and lower limit processing is as follows: the dynamic target superheat is limited to the range of 2℃ to 12℃, i.e., TSH_min = 2℃, TSH_max = 12℃.

[0072] Step 4, Segmented Asymmetric Proportional Adjustment: Calculate the deviation between the control superheat and the dynamic target superheat. Match the corresponding asymmetric adjustment gain according to the underheating or superheating range where the deviation is located. The adjustment gain matched in the underheating range is greater than the adjustment gain matched in the superheating range. Use the matched adjustment gain to calculate the basic opening adjustment amount.

[0073] This step uses asymmetric gain configuration to make the adjustment force greater in the underheated state than in the overheated state, thus prioritizing the suppression of liquid slugging risk while avoiding overheating oscillations.

[0074] In this step, the aforementioned deviation e = SH_ctrl - TSH.

[0075] The corresponding asymmetric adjustment gain is matched according to whether the deviation is in the underheating or overheating range. The corresponding relationship of the segmented proportional control is as follows:

[0076] When the deviation e ≤ -1℃ (severe underheating, risk of liquid slugging), the matching adjustment gain Kp = 3, and the electronic expansion valve is quickly closed.

[0077] When -1℃ < e ≤ 0℃ (slight underheating), the matching adjustment gain Kp = 2, and the electronic expansion valve is appropriately closed;

[0078] When 0℃<e≤1℃ (slight overheating), the matching adjustment gain Kp=1, and the electronic expansion valve is opened appropriately;

[0079] When e > 1℃ (severe overheating), the matching adjustment gain Kp = 0.5, and the electronic expansion valve is opened slowly to prevent excessive opening and liquid return.

[0080] In one example, the basic opening adjustment amount ΔP = Kp×e, where the unit of ΔP is the number of steps.

[0081] Before calculating the base opening adjustment amount using the adjustment gain obtained from the matching, the dead-zone adjustment step is also included:

[0082] The system determines whether the absolute value of the deviation is greater than a preset dead zone threshold, which can be selected as 0.3℃. If yes, the system calculates the basic opening adjustment amount; if no (i.e., |e| ≤ 0.3℃), the system sets the basic opening adjustment amount to zero and does not output any adjustment action to prevent frequent adjustments of the electronic expansion valve caused by minor fluctuations.

[0083] Step 5, Feedforward Compensation: Identify preset operating condition disturbance events, match the corresponding feedforward compensation opening degree according to the type of operating condition disturbance event. The direction and / or amplitude of the feedforward compensation opening degree corresponding to different types of operating condition disturbance events are different. The feedforward compensation opening degree is superimposed on the basic opening degree adjustment amount to obtain the total opening degree adjustment amount.

[0084] This step, by superimposing feedforward compensation, adjusts the opening degree in advance before the system disturbance occurs, thus shortening the recovery time after the disturbance.

[0085] Specifically, the preset operating condition disturbance events include compressor start-up, compressor shutdown, entering defrost mode, exiting defrost mode, outdoor fan start-up, outdoor fan shutdown, and exhaust fan start-up. The feedforward compensation settings corresponding to each operating condition disturbance event are as follows:

[0086] The compressor starts up in +30 steps, that is, the feedforward compensation opening ΔP_ff = +30 steps, which continues for 3 seconds and then linearly decays to 0.

[0087] The compressor stops in -20 steps, i.e., ΔP_ff = -20 steps, which lasts for 5 seconds and then returns to zero.

[0088] Enter the defrost corresponding step +80, that is, ΔP_ff = +80 steps, which runs through the entire defrost process, and operates at a fixed defrost opening during the defrost period;

[0089] Exiting defrost corresponds to -80 steps, i.e., ΔP_ff = -80 steps. The value immediately returns to zero upon exiting defrost. Furthermore, after exiting defrost, the opening returns to the initial value and the feedback adjustment is added.

[0090] Starting the outdoor fan corresponds to +15 steps, i.e., ΔP_ff = +15 steps; turning off the outdoor fan corresponds to -10 steps, i.e., ΔP_ff = -10 steps. Both of these steps decay after 10 seconds.

[0091] The dehumidification fan starts with +10 steps, i.e., ΔP_ff = +10 steps, and remains effective during dehumidification operation.

[0092] In one example, the total opening adjustment ΔP_total = ΔP + ΔP_ff, in steps, and each step of the electronic expansion valve corresponds to 0.1% of the valve opening, with a total stroke of 0 to 500 steps.

[0093] Step 6, Execution Output: Generate an electronic expansion valve drive signal based on the total opening adjustment amount, which is used to control the electronic expansion valve to adjust the valve opening.

[0094] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An adaptive overheat control method for an electronic expansion valve, characterized in that, Includes the following steps: Real-time acquisition of evaporator return gas temperature, evaporator coil temperature, compressor discharge temperature, outdoor ambient temperature, and cabin ambient temperature; The basic superheat is calculated based on the evaporator return gas temperature and the evaporator coil temperature. A benchmark target exhaust temperature is preset according to the current operating mode. The exhaust correction is calculated using the benchmark target exhaust temperature and the compressor exhaust temperature. The weighting weights corresponding to the basic superheat and the exhaust correction are configured according to the detection status of each temperature sensor. The control superheat is obtained after weighted fusion. The correction values ​​corresponding to the operating mode, outdoor ambient temperature and compressor running time are obtained respectively. Based on the preset reference superheat, the correction values ​​are superimposed on the preset reference superheat, and the dynamic target superheat is obtained after upper and lower limit processing. Calculate the deviation between the control superheat and the dynamic target superheat, and match the corresponding asymmetric adjustment gain according to the underheating or overheating range where the deviation is located. The adjustment gain matched in the underheating range is greater than the adjustment gain matched in the overheating range. The basic opening adjustment amount is calculated using the matched adjustment gain. Identify preset operating condition disturbance events, match the corresponding feedforward compensation opening degree according to the type of the operating condition disturbance event, wherein the direction and / or amplitude of the feedforward compensation opening degree corresponding to different types of operating condition disturbance events are different, and the feedforward compensation opening degree is superimposed on the basic opening degree adjustment amount to obtain the total opening degree adjustment amount. The total opening adjustment amount is used to generate an electronic expansion valve drive signal to control the electronic expansion valve to adjust the valve opening.

2. The adaptive overheat control method for an electronic expansion valve according to claim 1, characterized in that, The weighting method for the base superheat and the exhaust correction is as follows: When the return gas temperature sensor, evaporator coil temperature sensor, and exhaust temperature sensor are all normal, the weight of the base superheat is 0.7, and the weight of the exhaust correction is 0.

3. When the exhaust temperature sensor fails, the weight of the exhaust correction is reset to 0, and the weight of the base superheat is reset to 1. When the evaporator coil temperature sensor fails, the weighted fusion is stopped and the system enters a degraded operation mode.

3. The adaptive overheat control method for an electronic expansion valve according to claim 1, characterized in that, The method for determining the correction amount includes: The correction value is +1℃ when the operating mode is heating mode, -0.5℃ when it is cooling mode, and 0℃ when it is constant temperature mode. When the outdoor ambient temperature is ≤5℃, the corresponding correction is +2℃; when 5℃ < outdoor ambient temperature ≤10℃, the corresponding correction is +1℃; when the outdoor ambient temperature >10℃, the corresponding correction is 0℃. The correction amount for the compressor running time is ΔTSH_start = 2×(1 - t_run / 180), where t_run is the cumulative number of seconds the compressor runs, and the correction amount is valid for 180 seconds after the compressor starts.

4. The adaptive overheat control method for an electronic expansion valve according to claim 1, characterized in that, The upper and lower limit processing is to limit the dynamic target overheating within the range of 2°C to 12°C.

5. The adaptive overheat control method for an electronic expansion valve according to claim 1, characterized in that, The step of matching the corresponding asymmetric adjustment gain according to the underheating or overheating range of the deviation includes: When the deviation e ≤ -1℃, the matching adjustment gain Kp = 3; When -1℃ < e ≤ 0℃, the matching adjustment gain Kp = 2; When 0℃<e≤1℃, the matching adjustment gain Kp=1; When e > 1℃, the matching adjustment gain Kp = 0.

5.

6. The adaptive overheat control method for an electronic expansion valve according to claim 1, characterized in that, Before calculating the base opening adjustment amount using the adjustment gain obtained by matching, the method further includes: Determine whether the absolute value of the deviation is greater than a preset dead zone threshold. If yes, calculate the basic opening adjustment amount; otherwise, set the basic opening adjustment amount to zero.

7. The adaptive overheat control method for an electronic expansion valve according to claim 6, characterized in that, The preset dead zone threshold is 0.3℃.

8. The adaptive overheat control method for an electronic expansion valve according to claim 1, characterized in that, The exhaust correction amount is: SH_exh = α × (Td - Td_ref), Wherein, Td is the compressor exhaust temperature, Td_ref is the reference target exhaust temperature, and α is the exhaust correction coefficient, with a value ranging from 0.1 to 0.

3.

9. The adaptive overheat control method for an electronic expansion valve according to claim 1, characterized in that, The preset operating condition disturbance events include compressor start-up, compressor shutdown, entering defrost mode, exiting defrost mode, outdoor fan start-up, outdoor fan shutdown, and exhaust fan start-up. The feedforward compensation settings corresponding to each operating condition disturbance event are as follows: The compressor starts with +30 steps, which last for 3 seconds and then linearly decrease to 0. The compressor stops in step -20, and returns to zero after 5 seconds. Enter the corresponding +80 steps for defrosting, which will cover the entire defrosting process; Exit defrost (step 80), and immediately reset to zero upon exit. Starting the outdoor fan corresponds to +15 steps, and turning off the outdoor fan corresponds to -10 steps, both lasting for 10 seconds before decreasing. Turning on the dehumidification fan requires 10 steps and remains effective during dehumidification operation.

10. The adaptive overheat control method for an electronic expansion valve according to claim 1, characterized in that, The unit of the total opening adjustment is the number of steps, and each step of the electronic expansion valve corresponds to 0.1% of the valve opening.

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