Method and device for controlling electronic expansion valve, electronic equipment and storage medium

Abstract

The invention provides a method and device for controlling an electronic expansion valve, electronic equipment and a storage medium, the method is applied to the technical field of air conditioner control, and the method comprises the steps that under the condition that an air conditioner system is in a target working mode, the current refrigerant temperature of an air cooler outlet of the air conditioner system is obtained; based on the target working mode and the current refrigerant temperature, target exhaust pressure of a compressor of the air conditioning system is determined; wherein the efficiency of the air conditioning system under the target exhaust pressure is larger than a preset efficiency threshold value; the pressure difference value between the target exhaust pressure and the current actual exhaust pressure of the compressor is calculated; according to the pressure difference value, the target opening degree of the electronic expansion valve is calculated; and controlling the electronic expansion valve based on the target opening degree. The method can improve the performance of the carbon dioxide heat pump air-conditioning system and reduce the energy consumption of the air-conditioning system.

Description

Technical Field

[0001] The present application relates to the field of air-conditioning control technology, and more specifically, to a method, device, electronic device and storage medium for controlling an electronic expansion valve in the field of air-conditioning control technology. Background Art

[0002] New energy vehicles have developed rapidly in recent years, and heat pump air conditioning systems have become standard for new energy vehicles. Traditional heat pump air conditioning systems usually use refrigerants such as R-134a and R-1234yf, which show good energy efficiency and stability under mild climate conditions. However, in extremely cold environments (such as temperatures below -15°C), traditional heat pump air conditioning systems have problems such as insufficient heating capacity and slow heating speed.

[0003] In order to overcome the performance limitations of traditional refrigerants in extremely cold environments, carbon dioxide heat pump air conditioning systems came into being. Carbon dioxide heat pump air conditioners can operate efficiently in extremely cold environments of -35°C, and can effectively solve problems such as insufficient heating capacity and slow heating speed when using refrigerants such as R-134a and R-1234yf.

[0004] The traditional heat pump air conditioning system controls the evaporator outlet superheat or condenser outlet subcooling by controlling the opening of the electronic expansion valve, so that the system operates in a stable and efficient range. When the electronic expansion valve of the carbon dioxide heat pump system is controlled in the same way as the traditional heat pump system, the carbon dioxide heat pump system may operate outside the efficient range, resulting in the problem that the performance of the carbon dioxide heat pump system cannot be fully utilized. Summary of the invention

[0005] The present application provides a method, device, electronic device and storage medium for controlling an electronic expansion valve. The method can be applied to a carbon dioxide heat pump air conditioning system to improve the performance of the carbon dioxide heat pump air conditioning system and reduce the energy consumption of the air conditioning system.

[0006] In a first aspect, a method for controlling an electronic expansion valve is provided, the method comprising: when the air-conditioning system is in a target operating mode, obtaining a current refrigerant temperature at an air cooler outlet of the air-conditioning system; determining a target exhaust pressure of a compressor of the air-conditioning system based on the target operating mode and the current refrigerant temperature; wherein the efficiency of the air-conditioning system at the target exhaust pressure is greater than a preset efficiency threshold; calculating a pressure difference between the target exhaust pressure and a current actual exhaust pressure of the compressor; calculating a target opening of the electronic expansion valve based on the pressure difference; and controlling the electronic expansion valve based on the target opening.

[0007] In the above technical scheme, a target exhaust pressure is calculated by the current refrigerant temperature so that the efficiency of the compressor of the air-conditioning system is greater than a preset efficiency threshold, and a target opening of the electronic expansion valve is calculated based on the pressure difference between the target exhaust pressure and the current actual exhaust pressure to control the electronic expansion valve, thereby realizing the use of the target exhaust pressure to control the electronic expansion valve. The efficiency of the air-conditioning system at the target exhaust pressure is greater than the preset efficiency threshold. This method utilizes the target exhaust pressure of the carbon dioxide heat pump air-conditioning system in the transcritical cycle to make the efficiency of the air-conditioning system greater than the preset efficiency threshold to control the electronic expansion valve. This method can be better applied to the carbon dioxide heat pump air-conditioning system to ensure that the efficiency of the carbon dioxide heat pump air-conditioning system is maintained within a range greater than the preset efficiency threshold, thereby improving the performance of the carbon dioxide heat pump system and reducing the energy consumption of the vehicle.

[0008] In combination with the first aspect, in some possible implementations, the target exhaust pressure of the compressor of the air-conditioning system is determined based on the target operating mode and the current refrigerant temperature, including: determining a target coefficient and a target constant; wherein the target coefficient corresponds to the target operating mode and the current refrigerant temperature, and the target constant corresponds to the target operating mode and the current refrigerant temperature; multiplying the target coefficient by the current refrigerant temperature to obtain an intermediate value; adding the intermediate value and the target constant to obtain the target exhaust pressure.

[0009] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, before controlling the electronic expansion valve based on the target opening, the method also includes: processing the target opening based on a preset anti-shake opening and a preset rounding opening to obtain a processed target opening, so that the processed target opening is greater than or equal to the preset anti-shake opening and the processed target opening is an integer multiple of the preset rounding opening, wherein the preset rounding opening is smaller than the preset anti-shake opening; controlling the electronic expansion valve based on the target opening, including: controlling the electronic expansion valve based on the processed target opening.

[0010] In the above technical solution, the target opening is processed based on the preset anti-shake opening, which avoids the frequent switching of the electronic expansion valve within a small opening range, reduces the jitter of the electronic expansion valve, reduces mechanical wear, and improves the stability of the system. The target opening is processed based on the preset rounded opening to ensure that the opening of the electronic expansion valve is always within the range that the system can accurately control, reduce unnecessary fine-tuning, and extend the service life of the electronic expansion valve components.

[0011] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the electronic expansion valve is controlled based on the processed target opening, including: determining the opening difference according to the processed target opening and the current opening of the electronic expansion valve; determining the opening difference threshold based on the preset anti-shake opening; when the absolute value of the opening difference is greater than the opening difference threshold, determining the opening change rate corresponding to the opening difference, wherein the larger the absolute value of the opening difference, the larger the absolute value of the determined opening change rate; when the absolute value of the opening difference is less than or equal to the opening difference threshold, determining the opening change rate based on the preset rate; and controlling the electronic expansion valve based on the opening change rate.

[0012] In the above technical scheme, when the absolute value of the opening difference between the target opening and the actual opening is greater than the opening difference threshold, a larger opening change rate is determined for a larger opening difference, which can ensure that the air-conditioning system responds quickly based on a larger opening change rate and achieves rapid adjustment. A smaller opening change rate is determined for a smaller opening difference, which can ensure that the air-conditioning system is slowly adjusted based on a smaller opening change rate to ensure system stability.

[0013] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the target opening of the electronic expansion valve is calculated according to the pressure difference, including: determining the proportional coefficient and the integral coefficient of the PI controller based on the target operating mode and the pressure difference; multiplying the proportional coefficient by the pressure difference to obtain the proportional value; integrating the pressure difference based on the integral coefficient to obtain the integral value; and determining the target opening according to the proportional value and the integral value.

[0014] In the above technical solution, by determining the proportional coefficient and integral coefficient of the PI controller, the electronic expansion valve is PI-adjusted to determine the target opening. The proportional term can respond quickly and the integral term eliminates static errors, thereby achieving both the stability and response speed of the air-conditioning system. The PI controller only contains two items, proportional and integral. Compared with the PID controller, it reduces the number of parameters that need to be adjusted and reduces the complexity of parameter calibration.

[0015] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, when the air-conditioning system is in a target operating mode, the method also includes: determining a target outlet air temperature corresponding to the target operating mode; calculating the temperature difference between the actual outlet air temperature of the air-conditioning system and the target outlet air temperature; determining a feedforward value of the PI controller based on the temperature difference and the current ambient temperature; determining a target opening according to a proportional value and an integral value, including: adding the proportional value, the integral value and the feedforward value to obtain the target opening.

[0016] In the above technical solution, the feedforward value is determined by the temperature difference between the actual outlet air temperature and the target outlet air temperature and the ambient temperature, and the feedforward value is incorporated into the control logic of the PI controller to improve the response speed of the air conditioning system. Feedforward control can compensate for changes in the working state of the air conditioning system in advance, reduce the accumulation of errors, thereby avoiding over-adjustment and oscillation, and enhancing the robustness and stability of the air conditioning system.

[0017] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, before obtaining the current refrigerant temperature of the air cooler outlet of the air-conditioning system when the air-conditioning system is in the target operating mode, the method also includes: when it is determined that the air-conditioning system needs to be started and operates based on the target operating mode, judging whether the air-conditioning system is in a cold start scenario according to the operating status of the air-conditioning system; when it is determined that the air-conditioning system is in a cold start scenario, determining the cold start opening of the electronic expansion valve based on the current ambient temperature; based on the cold start opening, controlling the cold start of the air-conditioning system; when it is determined that the air-conditioning system has completed the cold start, controlling the air-conditioning system to enter the target operating mode.

[0018] In the above technical scheme, when it is determined that the air-conditioning system is in a cold start scenario, the corresponding cold start opening is determined based on the ambient temperature, and the electronic expansion valve is directly controlled based on the determined cold start opening to achieve a cold start. The cold start opening is a preset fixed opening of the electronic expansion valve. The opening of the electronic expansion valve determines the refrigerant flow rate. Cold starting the air-conditioning system based on the preset fixed opening of the electronic expansion valve can ensure that there is sufficient refrigerant flow rate at the initial stage of the cold start of the air-conditioning system, thereby protecting the compressor and improving the stability of the system, avoiding the lag and uncertainty of PID control during cold start, which results in too little circulating refrigerant in the air-conditioning system at the initial stage of cold start, too little return oil, and the compressor cannot be effectively cooled and is damaged by dry grinding, thereby increasing the service life of the compressor.

[0019] In summary, the present application calculates the target opening of the electronic expansion valve based on the pressure difference between the target exhaust pressure and the current actual exhaust pressure, and utilizes the performance control of the electronic expansion valve that the efficiency of the air conditioning system is greater than the preset efficiency threshold value when the target exhaust pressure exists in the transcritical cycle of the carbon dioxide heat pump air conditioning system, which can be better applied to the carbon dioxide heat pump air conditioning system, improve the performance of the carbon dioxide heat pump system, and reduce the energy consumption of the vehicle. The target opening is processed based on the preset anti-shake opening and the preset rounded opening, which avoids the frequent switching of the electronic expansion valve within a small opening range, reduces the jitter of the electronic expansion valve, reduces mechanical wear, reduces unnecessary fine-tuning, extends the service life of the electronic expansion valve components, and improves the stability of the system. For a larger opening difference, a larger opening change rate is determined, which can ensure that the air conditioning system responds quickly based on a larger opening change rate and achieves rapid adjustment. For a smaller opening difference, a smaller opening change rate is determined, which can ensure that the air conditioning system is slowly adjusted based on a smaller opening change rate, ensuring system stability. PI adjustment of the electronic expansion valve reduces the number of parameters that need to be adjusted compared to the PID controller, and reduces the complexity of parameter calibration. A fixed cold start opening is determined based on the ambient temperature to perform a cold start, ensuring that the air conditioning system has sufficient refrigerant flow at the initial cold start, thereby protecting the compressor and improving the stability of the system.

[0020] In a second aspect, a device for controlling an electronic expansion valve is provided, the device comprising: a temperature acquisition module, for acquiring the current refrigerant temperature of an air cooler outlet of the air-conditioning system when the air-conditioning system is in a target operating mode; an exhaust pressure calculation module, for determining a target exhaust pressure of a compressor of the air-conditioning system based on the target operating mode and the current refrigerant temperature; wherein the efficiency of the air-conditioning system at the target exhaust pressure is greater than a preset efficiency threshold; a pressure difference calculation module, for calculating the pressure difference between the target exhaust pressure and the current actual exhaust pressure of the compressor; a target opening calculation module, for calculating the target opening of the electronic expansion valve according to the pressure difference; and an electronic expansion valve control module, for controlling the electronic expansion valve based on the target opening.

[0021] In combination with the second aspect, in some possible implementations, the exhaust pressure calculation module is specifically used to determine a target coefficient and a target constant; wherein the target coefficient corresponds to the target operating mode and the current refrigerant temperature, and the target constant corresponds to the target operating mode and the current refrigerant temperature; the target coefficient is multiplied by the current refrigerant temperature to obtain an intermediate value; the intermediate value and the target constant are added to obtain the target exhaust pressure.

[0022] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the device also includes: a processing module, used to process the target opening based on a preset anti-shake opening and a preset rounding opening to obtain a processed target opening, so that the processed target opening is greater than or equal to the preset anti-shake opening and the processed target opening is an integer multiple of the preset rounding opening, wherein the preset rounding opening is smaller than the preset anti-shake opening; the electronic expansion valve control module is specifically used to control the electronic expansion valve based on the processed target opening.

[0023] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the electronic expansion valve control module is specifically used to determine the opening difference based on the processed target opening and the current opening of the electronic expansion valve; determine the opening difference threshold based on the preset anti-shake opening; when the absolute value of the opening difference is greater than the opening difference threshold, determine the opening change rate corresponding to the opening difference, wherein the larger the absolute value of the opening difference, the larger the absolute value of the determined opening change rate; when the absolute value of the opening difference is less than or equal to the opening difference threshold, determine the opening change rate based on the preset rate; and control the electronic expansion valve based on the opening change rate.

[0024] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the target opening calculation module is specifically used to determine the proportional coefficient and integral coefficient of the PI controller based on the target operating mode and the pressure difference; multiply the proportional coefficient by the pressure difference to obtain the proportional value; integrate the pressure difference based on the integral coefficient to obtain the integral value; and determine the target opening based on the proportional value and the integral value.

[0025] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the device also includes: a feedforward value determination module, used to determine the target outlet air temperature corresponding to the target operating mode; calculate the temperature difference between the actual outlet air temperature of the air-conditioning system and the target outlet air temperature; based on the temperature difference and the current ambient temperature, determine the feedforward value of the PI controller; the target opening calculation module is specifically used to add the proportional value, the integral value and the feedforward value to obtain the target opening.

[0026] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the device also includes: a cold start module, which is used to determine whether the air-conditioning system is in a cold start scenario according to the operating status of the air-conditioning system when it is determined that the air-conditioning system needs to be started and operates based on the target working mode; when it is determined that the air-conditioning system is in a cold start scenario, determine the cold start opening of the electronic expansion valve based on the current ambient temperature; based on the cold start opening, control the cold start of the air-conditioning system; when it is determined that the air-conditioning system has completed the cold start, control the air-conditioning system to enter the target working mode.

[0027] In a third aspect, an electronic device is provided, comprising a memory and a processor. The memory is used to store executable program code, and the processor is used to call and run the executable program code from the memory, so that the electronic device executes the method in the first aspect or any possible implementation of the first aspect.

[0028] In a fourth aspect, a computer program product is provided, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method in the first aspect or any possible implementation of the first aspect.

[0029] In a fifth aspect, a computer-readable storage medium is provided, which stores a computer program code. When the computer program code runs on a computer, the computer executes the method in the above-mentioned first aspect or any possible implementation manner of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flow chart of a method for controlling an electronic expansion valve provided in an embodiment of the present application.

[0031] Figure 2 It is a flow chart of another method for controlling an electronic expansion valve provided in an embodiment of the present application.

[0032] Figure 3 It is a structural schematic diagram of a device for controlling an electronic expansion valve provided in an embodiment of the present application.

[0033] Figure 4 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] The technical solution in the present application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0035] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0036] New energy vehicles have developed rapidly in recent years, and heat pump air conditioning systems have become their standard. Traditional heat pump air conditioning systems usually use refrigerants such as R-134a and R-1234yf, which show good energy efficiency and stability under mild climate conditions. However, in extremely cold environments (such as temperatures below -15°C), traditional heat pump air conditioning systems have obvious performance problems, which are as follows:

[0037] 1. Insufficient heating capacity: In low temperature environments, the evaporation temperature of traditional refrigerants is low, resulting in a significant reduction in the heating capacity of the system.

[0038] 2. When there is no PTC (Positive Temperature Coefficient) coupling system, the heating speed is slow: Due to insufficient heating capacity, the temperature inside the car rises slowly, affecting the comfort of passengers.

[0039] Existing Technology In order to overcome the performance limitations of traditional refrigerants in extremely cold environments, carbon dioxide heat pump air conditioning systems came into being. As a natural refrigerant, carbon dioxide has a wide operating temperature range, allowing carbon dioxide heat pump air conditioners to operate efficiently in extremely cold environments of -35°C. Compared with traditional refrigerants, carbon dioxide has higher energy efficiency under low temperature conditions, can provide more sufficient heating capacity, and provide a faster heating rate.

[0040] The traditional electronic expansion valve control method mainly maintains the stable operation of the system by adjusting the superheat of the evaporator outlet or the subcooling of the condenser outlet. However, the CO2 heat pump air conditioning system operates in a transcritical cycle most of the time, and the compressor exhaust pressure has a great impact on the energy efficiency of the entire system. In the transcritical cycle, the traditional electronic expansion valve control method may cause the system to be unable to operate in the optimal energy efficiency range. It is easy to affect the energy efficiency and stability of the CO2 heat pump air conditioning system.

[0041] Since there is an optimal compressor exhaust pressure in the transcritical cycle of the carbon dioxide heat pump air conditioning system, the energy efficiency of the system can be optimized under this pressure. Based on this, the present application proposes a method for controlling an electronic expansion valve, which is applied to the carbon dioxide heat pump air conditioning system, and controls the electronic expansion valve based on the compressor exhaust pressure to ensure that the energy efficiency of the carbon dioxide heat pump air conditioning system is maintained at the optimal level.

[0042] Figure 1 It is a flow chart of a method for controlling an electronic expansion valve provided in an embodiment of the present application.

[0043] For example, Figure 1 As shown, the method 100 includes:

[0044] Step 101, when the air conditioning system is in a target working mode, obtaining a current refrigerant temperature at an air cooler outlet of the air conditioning system;

[0045] Step 102, determining a target exhaust pressure of a compressor of the air-conditioning system based on a target operating mode and a current refrigerant temperature; wherein the efficiency of the air-conditioning system at the target exhaust pressure is greater than a preset efficiency threshold;

[0046] Step 103, calculating the pressure difference between the target exhaust pressure and the current actual exhaust pressure of the compressor;

[0047] Step 104, calculating the target opening of the electronic expansion valve according to the pressure difference;

[0048] Step 105: Control the electronic expansion valve based on the target opening.

[0049] exist Figure 1 In the shown embodiment, a target exhaust pressure is calculated by the current refrigerant temperature so that the efficiency of the compressor of the air-conditioning system is greater than a preset efficiency threshold, and a target opening of the electronic expansion valve is calculated based on the pressure difference between the target exhaust pressure and the current actual exhaust pressure to control the electronic expansion valve, thereby realizing the use of the target exhaust pressure to control the electronic expansion valve. The efficiency of the air-conditioning system at the target exhaust pressure is greater than the preset efficiency threshold. This method utilizes the target exhaust pressure of the carbon dioxide heat pump air-conditioning system in the transcritical cycle to control the electronic expansion valve so that the efficiency of the air-conditioning system is greater than the preset efficiency threshold. This method can be better applied to the carbon dioxide heat pump air-conditioning system to ensure that the efficiency of the carbon dioxide heat pump air-conditioning system is maintained within a range greater than the preset efficiency threshold, thereby improving the performance of the carbon dioxide heat pump system and reducing the energy consumption of the vehicle.

[0050] Below Figure 1 The specific implementation of each step in the embodiment shown is described in detail:

[0051] In step 101, the air conditioning system is specifically a carbon dioxide heat pump air conditioning system, and the refrigerant of the carbon dioxide heat pump air conditioning system is carbon dioxide. The air conditioning system can be a vehicle air conditioning system, or an air conditioning system in a home or industrial scenario.

[0052] It is understandable that the air conditioning system generally includes multiple working modes to meet the needs of users under different environmental conditions. Specifically, the air conditioning system may include multiple working modes: shutdown mode, ventilation mode, cooling mode, heating mode, and dehumidification mode.

[0053] Among them, the shutdown mode means that the air conditioning system completely stops running and does not perform any cooling, heating or ventilation operations. It is used in scenarios where air conditioning is not needed. The ventilation mode means that the air conditioning system only starts the fan and does not perform cooling or heating operations to circulate indoor air and maintain air circulation. It is used in scenarios where the indoor temperature is suitable but air circulation needs to be improved. The cooling mode is used in high-temperature scenarios, where the refrigerant absorbs heat to lower the temperature. The heating mode is used in low-temperature scenarios, where the refrigerant dissipates heat to increase the temperature. The dehumidification mode is used in scenarios with high humidity, where the refrigerant absorbs moisture in the air, condenses the water vapor into water droplets and discharges them.

[0054] The target working mode can be any one of the cooling mode, the heating mode or the dehumidification mode. The air conditioning system needs to use refrigerant in the target working mode, so it is necessary to adjust the refrigerant flow by controlling the opening of the electronic expansion valve to optimize the energy efficiency of the air conditioning system.

[0055] An air cooler is a device used in air conditioning systems to cool high-temperature and high-pressure gaseous carbon dioxide to lower its temperature. The air cooler includes an inlet and an outlet. The inlet of the air cooler is where the high-temperature and high-pressure gaseous refrigerant enters the air cooler. In a carbon dioxide refrigeration system, after being compressed by a compressor, the gaseous carbon dioxide enters the air cooler through the inlet of the air cooler for cooling; the outlet of the air cooler is where the cooled gaseous refrigerant leaves the air cooler. The refrigerant temperature at the outlet is usually lowered, close to the ambient temperature or the set cooling temperature, and the refrigerant output from the outlet of the air cooler is used to adjust the temperature.

[0056] The air conditioning system may be provided with a temperature sensor at the air cooler outlet to collect the refrigerator temperature at the air cooler outlet. When it is determined that the air conditioning system is in the target working mode, the current refrigerant temperature collected by the temperature sensor provided at the air cooler outlet may be obtained.

[0057] In the prior art, air conditioning systems usually completely use a set of control methods to control electronic expansion valves, such as completely using PID to control electronic expansion valves. If the air conditioning system still uses PID to control the electronic expansion valve during cold start, it is easy to cause the air conditioning system to have too little circulating refrigerant and too little return oil at the beginning of cold start, resulting in the compressor not being effectively cooled and being damaged by dry grinding. The lower the ambient temperature of the air conditioning system, the greater the impact. Based on this, the present application proposes a method for controlling an electronic expansion valve to solve the above problems, as shown in the following embodiments:

[0058] In one possible implementation, when the air-conditioning system is in a target operating mode, before obtaining the current refrigerant temperature at the air cooler outlet of the air-conditioning system, the method also includes: when it is determined that the air-conditioning system needs to be started and operates based on the target operating mode, judging whether the air-conditioning system is in a cold start scenario according to the operating status of the air-conditioning system; when it is determined that the air-conditioning system is in a cold start scenario, determining the cold start opening of the electronic expansion valve based on the current ambient temperature; based on the cold start opening, controlling the cold start of the air-conditioning system; when it is determined that the air-conditioning system has completed the cold start, controlling the air-conditioning system to enter the target operating mode.

[0059] When the air-conditioning system is an air-conditioning system for home or industrial scenarios, the air-conditioning system generally includes a controller, which may include a button for turning on or off the air-conditioning system, and buttons for the above-mentioned multiple working modes. The user can control the air-conditioning system to turn on by using the button for turning on the air-conditioning system in the controller, and control the air-conditioning system to enter the target working mode by using the buttons for cooling mode, heating mode or dehumidification mode in the controller.

[0060] When the air conditioning system is a vehicle-mounted air conditioning system, the user can control the air conditioning system to start through the large screen of the vehicle or the control panel of the air conditioning system on an electronic device such as a mobile phone connected to the vehicle. The air conditioning system can collect relevant sensor values ​​and user operation data to calculate the working mode that the air conditioning system needs to operate. Among them, the user operation data may include: data such as the target air outlet temperature and target air volume set by the user in the control panel for the operation of the air conditioning system. In the following embodiments of this application, the air conditioning system is taken as an example of a vehicle-mounted air conditioning system.

[0061] Exemplarily, the relevant sensor values ​​collected by the air conditioning system may include data such as the temperature in the vehicle and the humidity in the vehicle. The air conditioning system may determine the working mode of the air conditioning system through data such as the target air outlet temperature, the temperature in the vehicle and the humidity in the vehicle. For example, the air conditioning system may determine that the working mode of the air conditioning system is the cooling mode when the target air outlet temperature is lower than the temperature in the vehicle. When the target air outlet temperature is higher than the temperature in the vehicle, the working mode of the air conditioning system is determined to be the heating mode. When the target air outlet temperature is equal to the temperature in the vehicle and the humidity in the vehicle is higher than the preset humidity threshold, the working mode of the air conditioning system is determined to be the dehumidification mode.

[0062] When the air conditioning system determines that the working mode to be entered is any one of the cooling mode, the heating mode or the dehumidification mode, it can be determined that the air conditioning system needs to be started and operated based on the target working mode. At this time, the operating status of the air conditioning system is obtained to determine whether the air conditioning system is in a cold start scenario.

[0063] Among them, the obtained operating status of the air-conditioning system may include obtaining the interval time between the current startup of the air-conditioning system and the last shutdown and the current external ambient temperature of the vehicle. When the interval time is greater than the preset time and / or the current external ambient temperature is lower than the preset temperature, it can be determined that the air-conditioning system is in a cold start scenario.

[0064] The ambient temperature is specifically the ambient temperature outside the vehicle, and the cold start opening is the fixed opening of the electronic expansion valve when the air conditioning system is started at a certain ambient temperature set in advance. At this fixed opening, the refrigerant flow is usually greater than the preset flow to ensure sufficient refrigerant flow during cold start.

[0065] It is understandable that the fixed opening of the electronic expansion valve when starting the air-conditioning system under different ambient temperatures can be set in advance to obtain a first mapping table, and the first mapping table is stored in the air-conditioning system.

[0066] Table 1

[0067] Ambient temperature (℃) [0，-10) [-10,-20) [-20,-30) [-30,-40) ... Fixed opening (degrees) 5 6 7 8 ...

[0068] Exemplarily, the first mapping table is shown in Table 1, where the ambient temperature [0°C, -10°C) corresponds to a fixed opening of 5 degrees, the ambient temperature [-10°C, -20°C) corresponds to a fixed opening of 6 steps, the ambient temperature [-20°C, -30°C) corresponds to a fixed opening of 7 steps, and the ambient temperature [-30°C, -40°C) corresponds to a fixed opening of 8 steps.

[0069] When it is determined that the air-conditioning system is in a cold start scenario, the first mapping table can be searched based on the current ambient temperature outside the vehicle, and the fixed opening of the electronic expansion valve corresponding to the current ambient temperature outside the vehicle can be determined as the cold start opening. The opening of the electronic expansion valve is then controlled to be the cold start opening so that the air-conditioning system starts running based on the cold start opening, that is, starts a cold start.

[0070] For example, the current ambient temperature outside the vehicle is -15°C, and Table 1 is checked to determine that -15°C is within the ambient temperature range of [-10°C, -20°C), and the cold start opening corresponding to the ambient temperature -15°C can be determined to be a fixed opening 6 steps corresponding to [-10°C, -20°C). Then, the electronic expansion valve is controlled to open to the cold start opening 6 steps, so that the air conditioning system starts to operate based on the cold start opening 6 steps, that is, the cold start is started.

[0071] After the air-conditioning system runs for a period of time (for example, two minutes) based on the cold start opening, it is determined whether the cold start is completed based on the state jump condition of the air-conditioning system. Among them, the state jump condition can be: the refrigerant temperature on the high-pressure side of the air-conditioning system compressor is greater than the preset temperature and the exhaust pressure is greater than the preset pressure. The high-pressure side of the compressor is the outlet side of the compressor. Specifically, the refrigerant temperature and exhaust pressure on the outlet side of the compressor can be obtained after the air-conditioning system runs for two minutes based on the cold start opening. When it is determined that the refrigerant temperature is greater than the preset temperature and the exhaust pressure is greater than the preset pressure, it is determined that the air-conditioning system has completed the cold start. After determining that the air-conditioning system has completed the cold start, the flag signal of the operating mode of the air-conditioning system is set to the signal of the target working mode, and the vehicle is controlled to enter the target working mode.

[0072] In some embodiments, when the calculated working mode that the air-conditioning system needs to enter is the shutdown mode or the ventilation mode, no subsequent operation is performed and the working mode calculation is restarted.

[0073] In some embodiments, when the air-conditioning system runs for a period of time (for example, two minutes) based on the cold start opening and it is determined that the air-conditioning system has not completed the cold start, it returns to the previous step, re-searches the first mapping table based on the ambient temperature outside the vehicle, obtains the fixed opening of the electronic expansion valve to obtain a new cold start opening, and controls the air-conditioning system to perform a cold start based on the new cold start opening again.

[0074] In the above method, when it is determined that the air-conditioning system is in a cold start scenario, the corresponding cold start opening is determined based on the ambient temperature, and the electronic expansion valve is directly controlled based on the determined cold start opening to achieve a cold start. The cold start opening is a preset fixed opening of the electronic expansion valve. The opening of the electronic expansion valve determines the refrigerant flow rate. Cold starting the air-conditioning system based on the preset fixed opening of the electronic expansion valve can ensure that there is sufficient refrigerant flow rate at the initial stage of the cold start of the air-conditioning system, thereby protecting the compressor and improving the stability of the system, avoiding the lag and uncertainty of PID control during cold start, which may result in too little circulating refrigerant in the air-conditioning system at the initial stage of cold start, too little return oil, and the compressor cannot be effectively cooled and is damaged by dry grinding, thereby increasing the service life of the compressor.

[0075] In step 102, the target exhaust pressure may also be referred to as the optimal exhaust pressure, and the preset efficiency threshold is used to determine whether the energy efficiency of the air conditioning system is optimal. If it is determined that the efficiency of the air conditioning system is greater than the preset efficiency threshold, it can be determined that the energy efficiency of the air conditioning system is optimal. The energy efficiency of the air conditioning system is optimal at the target exhaust pressure.

[0076] There is a fitted linear relationship between the refrigerant temperature at the air cooler outlet and the optimal exhaust pressure of the compressor under the target working mode. Therefore, based on the current refrigerant temperature and the target working mode, the optimal exhaust pressure of the compressor of the air-conditioning system under the current refrigerant temperature and the target working mode can be calculated to obtain the target exhaust pressure.

[0077] In one possible implementation, based on the target operating mode and the current refrigerant temperature, the target exhaust pressure of the compressor of the air-conditioning system is determined, including: determining a target coefficient and a target constant; wherein the target coefficient corresponds to the target operating mode and the current refrigerant temperature, and the target constant corresponds to the target operating mode and the current refrigerant temperature; multiplying the target coefficient by the current refrigerant temperature to obtain an intermediate value; adding the intermediate value and the target constant to obtain the target exhaust pressure.

[0078] Among them, the target coefficient and target constant are two parameters used to calculate the target exhaust pressure. The target coefficient is a proportional factor that indicates the rate of change of the target exhaust pressure with the refrigerant temperature. The target constant is an offset that indicates the reference exhaust pressure at a certain refrigerant temperature.

[0079] In the same working mode, there is a certain fitting relationship between the refrigerant temperature and the target exhaust pressure of the air-conditioning system. Specifically, the fitting relationship between the refrigerant temperature and the target exhaust pressure in the same working mode can be represented by multiple linear segments (i.e., broken lines), each of which corresponds to a coefficient and a constant. In different working modes, the fitting relationship between the refrigerant temperature and the target exhaust pressure of the air-conditioning system is different.

[0080] The air-conditioning system may store a second mapping table between different operating modes and refrigerant temperatures and coefficients of the fitted linear segment. Based on the target operating mode and the current refrigerant temperature, the second mapping table may be searched to determine the target coefficient corresponding to the target operating mode and the current refrigerant temperature.

[0081] Table 2

[0082] (0℃,20℃] (20℃,50℃] (50℃,65℃] (65℃,75℃] ... Cooling mode 0.2 0.13 0.7 0.3 ... Heating mode 0.1 0.5 0.4 0.2 ... Dehumidification mode 0.3 0.2 0.6 0.4 ...

[0083] The second mapping table is shown in Table 2. The cooling working mode and the refrigerant temperature range [0°C, 20°C] correspond to a coefficient of 0.2, the cooling working mode and the refrigerant temperature range [20°C, 50°C] correspond to a coefficient of 0.13, the cooling working mode and the refrigerant temperature range [50°C, 65°C] correspond to a coefficient of 0.7, and the cooling working mode and the refrigerant temperature range [65°C, 75°C] correspond to a coefficient of 0.3. The heating working mode and the refrigerant temperature range [0°C, 20°C] correspond to a coefficient of 0.1, and the heating working mode and the refrigerant temperature range [20°C, 50°C] correspond to The coefficient is 0.5, the heating working mode and the refrigerant temperature range [50℃, 65℃] correspond to the coefficient 0.4, and the heating working mode and the refrigerant temperature range [65℃, 75℃] correspond to the coefficient 0.2. The dehumidification working mode and the refrigerant temperature range [0℃, 20℃] correspond to the coefficient 0.3, the dehumidification working mode and the refrigerant temperature range [20℃, 50℃] correspond to the coefficient 0.2, the dehumidification working mode and the refrigerant temperature range [50℃, 65℃] correspond to the coefficient 0.6, and the dehumidification working mode and the refrigerant temperature range [65℃, 75℃] correspond to the coefficient 0.4.

[0084] Exemplarily, the target working mode is the cooling mode, and the current refrigerant temperature is 35° C., which is within the range of (20° C., 50° C.). Lookup Table 2 can determine that the target coefficient corresponding to the cooling mode and the current refrigerant temperature of 35° C. is 0.13.

[0085] The air-conditioning system may store a third mapping table between different operating modes and refrigerant temperatures and constants of the fitted linear segment. Based on the target operating mode and the current refrigerant temperature, the third mapping table may be searched to determine the target constant corresponding to the target operating mode and the current refrigerant temperature.

[0086] Table 3

[0087] (0℃,20℃] (20℃,50℃] (50℃,65℃] (65℃,75℃] ... Cooling mode 3 5 5 4 ... Heating mode 1 5 2 3 ... Dehumidification mode 2 4 5 7 ...

[0088] The third mapping table is shown in Table 3. The cooling working mode and the refrigerant temperature range [0°C, 20°C] correspond to constant 3, the cooling working mode and the refrigerant temperature range [20°C, 50°C] correspond to constant 5, the cooling working mode and the refrigerant temperature range [50°C, 65°C] correspond to constant 5, and the cooling working mode and the refrigerant temperature range [65°C, 75°C] correspond to constant 4. The heating working mode and the refrigerant temperature range [0°C, 20°C] correspond to constant 1, the heating working mode and the refrigerant temperature range [20°C, 50°C] correspond to constant 5. The corresponding constant is 5. The heating working mode and the refrigerant temperature range [50℃, 65℃] correspond to constant 2. The heating working mode and the refrigerant temperature range [65℃, 75℃] correspond to constant 3. The dehumidification working mode and the refrigerant temperature range [0℃, 20℃] correspond to constant 2. The dehumidification working mode and the refrigerant temperature range [20℃, 50℃] correspond to constant 4. The dehumidification working mode and the refrigerant temperature range [50℃, 65℃] correspond to constant 5. The dehumidification working mode and the refrigerant temperature range [65℃, 75℃] correspond to constant 7.

[0089] Exemplarily, the target working mode is the cooling mode, and the current refrigerant temperature is 35° C., which is within the range of (20° C., 50° C.). Lookup Table 3 can determine that the target constant corresponding to the cooling mode and the current refrigerant temperature of 35° C. is 5.

[0090] After obtaining the target coefficient and the target constant, the target coefficient can be multiplied by the current refrigerant temperature to obtain an intermediate value, and then the intermediate value and the target constant are added to obtain the target exhaust pressure. In some embodiments, the target coefficient is called a target constant coefficient, and the target constant is called a target offset constant.

[0091] The formula for calculating the target exhaust pressure is shown in the following formula (1):

[0092] P opt =K*T gc,out +C offset (1)

[0093] Among them, P in formula (1) opt is the target exhaust pressure, in MPa; K is the target constant coefficient, i.e. the target coefficient; T gc，out is the current refrigerant temperature at the air cooler outlet; C offset is the target offset constant, that is, the target constant, K*T gc,out That is the intermediate value mentioned above.

[0094] For example, the target coefficient is 0.13, the target constant is 5, and the current refrigerant temperature is 35°C. Substituting the target coefficient 0.13, the target constant 5, and the current refrigerant temperature 35°C into formula (1), the target exhaust pressure P can be calculated. opt=0.13*35+5=9.55MPa.

[0095] In step 103, a pressure sensor may be provided in the compressor of the air conditioning system to collect the actual exhaust pressure of the compressor. After the target exhaust pressure is calculated, the actual exhaust pressure currently collected by the pressure sensor may be obtained. The target exhaust pressure is subtracted from the actual exhaust pressure to obtain a pressure difference.

[0096] As in the above embodiment, the target exhaust pressure is P opt , the actual exhaust pressure can be recorded as P act , the target exhaust pressure P opt Subtract the actual exhaust pressure P act The pressure difference is recorded as P err .

[0097] In step 104, the pressure difference can be used as a control error, and the opening of the electronic expansion valve that needs to be adjusted can be calculated using the control error and a control algorithm preset by the air conditioning system (such as a PID control algorithm or a PI control algorithm) to obtain a target opening.

[0098] The following embodiment introduces the detailed implementation process of calculating the target opening based on the PI control algorithm:

[0099] In one possible implementation, the target opening of the electronic expansion valve is calculated according to the pressure difference, including: determining the proportional coefficient and integral coefficient of the PI controller based on the target operating mode and the pressure difference; multiplying the proportional coefficient by the pressure difference to obtain the proportional value; integrating the pressure difference based on the integral coefficient to obtain the integral value; and determining the target opening according to the proportional value and the integral value.

[0100] The PI controller consists of two parts: the proportional term and the integral term. The proportional term is the most direct part of the PI controller, which is used to proportionally adjust the control output (i.e., the target opening) according to the current error (i.e., the pressure difference mentioned above), and has the characteristics of fast response. The proportional coefficient determines the response strength of the proportional term to the error, and choosing the appropriate proportional coefficient is crucial to the performance of the system.

[0101] Specifically, a suitable proportional coefficient can be determined based on the target working mode and pressure difference of the air conditioning system. For example, the proportional coefficient can be gradually increased until the controller starts to oscillate continuously, and the critical gain and oscillation period at this time are recorded. Then, based on these parameters, a suitable proportional coefficient can be selected according to certain rules.

[0102] Although the proportional term can quickly reduce the error, it cannot completely eliminate the static error. The integral term can be used to eliminate the static error accumulated by the proportional term in the past and gradually adjust the control output. The integral coefficient determines the speed and strength of the integral term to accumulate and eliminate static errors. Choosing a suitable integral coefficient is crucial to the stability, response speed and control accuracy of the system.

[0103] After determining the proportional coefficient, the integral coefficient can be gradually increased from 0. By limiting the maximum absolute value of the integral term accumulation value, the opening of the adjusted electronic expansion valve is limited to not more than 2 / 3 of the effective throttling section to obtain the integral coefficient. Among them, the maximum value can be preset, and the effective throttling section refers to the valve core part of the electronic expansion valve that actually participates in the throttling effect. When the valve core is opened, the refrigerant flows through the gap between the valve core and the valve seat, forming a throttling effect, thereby reducing the pressure of the refrigerant and regulating the flow.

[0104] The principle of integral coefficient adjustment is that after the system is relatively stable, the oscillation frequency cannot be too high and the amplitude cannot be too large. In addition, the overshoot after the first amplitude cannot cause significant changes in the compressor exhaust pressure and outlet air temperature, so that the heat pump system can operate stably.

[0105] After determining the proportional coefficient and the integral coefficient, the proportional coefficient can be multiplied by the pressure difference to obtain the proportional value; the integral coefficient can be multiplied by the pressure difference and integrated to obtain the integral value; the proportional value and the integral value can be added to obtain the target opening.

[0106] The formula for calculating the target opening is shown in the following formula (2):

[0107]

[0108] Among them, EXV_P in formula (2) cal is the calculated output value of the PI controller, i.e. the target opening; K p is the proportional coefficient of the PI controller, P err for Pressure difference; K p (t)*P err (t) is the ratio value; K i is the integral coefficient of the PI controller, and is the integral value.

[0109] In the above method, by determining the proportional coefficient and integral coefficient of the PI controller, the electronic expansion valve is adjusted by PI to determine the target opening. The proportional term can respond quickly and the integral term eliminates static errors, thereby achieving both the stability and response speed of the air-conditioning system. The PI controller only contains two items, proportional and integral. Compared with the PID controller, it reduces the number of parameters that need to be adjusted and reduces the complexity of parameter calibration.

[0110] In one possible implementation, when the air-conditioning system is in a target operating mode, the method also includes: determining a target outlet air temperature corresponding to the target operating mode; calculating the temperature difference between the actual outlet air temperature of the air-conditioning system and the target outlet air temperature; determining a feedforward value of a PI controller based on the temperature difference and the current ambient temperature; and determining a target opening according to a proportional value and an integral value, including: adding the proportional value, the integral value, and the feedforward value to obtain the target opening.

[0111] The target air outlet temperature refers to the air temperature set by the user as the desired air output by the air conditioning system, which is the air outlet temperature that the air conditioning system needs to reach. For example, in the above embodiment, the target air outlet temperature is set by the user based on the control panel. The target air outlet temperature set by the user can be obtained and recorded as T airout，tar .

[0112] The actual air outlet temperature refers to the actual air temperature output by the air conditioning system. A temperature sensor can be set at the air outlet of the air conditioning system to collect the actual air outlet temperature of the air conditioning system in real time. The actual air outlet temperature collected by the temperature sensor can be obtained and recorded as T airout，act .

[0113] The target air outlet temperature T airout，tar Subtract the actual outlet temperature T airout，act , get the temperature difference, and record the temperature difference as T airout，err .

[0114] The ambient temperature is the current ambient temperature outside the vehicle. The air conditioning system may store a fourth mapping table that contains mapping relationships between temperature difference and ambient temperature and feedforward value. After obtaining the temperature difference, the fourth mapping table may be searched based on the temperature difference to obtain the feedforward value corresponding to the temperature difference.

[0115] Table 4

[0116] 2℃ 4℃ 6℃ 8℃ ... 10℃ 4 4.5 5 5.5 15℃ 5 5.5 6 6.5 20℃ 6 6.5 7 7.5 ...

[0117] Exemplarily, the fourth mapping table is shown in Table 4, the temperature difference includes: 2°C, 4°C, 6°C and 8°C, etc., and the ambient temperature includes: 10°C, 15°C, 20°C, etc. The ambient temperature of 10°C and the temperature difference of 2°C correspond to 4 steps of feedforward value; the ambient temperature of 10°C and the temperature difference of 4°C correspond to 4.5 steps of feedforward value; the ambient temperature of 10°C and the temperature difference of 6°C correspond to 5 steps of feedforward value; the ambient temperature of 10°C and the temperature difference of 8°C correspond to 5.5 steps of feedforward value. The ambient temperature of 15°C and the temperature difference of 2°C correspond to 5 steps of feedforward value; the ambient temperature of 15°C and the temperature difference of 4°C correspond to 5.5 steps of feedforward value; the ambient temperature of 15°C and the temperature difference of 6°C correspond to 6 steps of feedforward value; the ambient temperature of 15°C and the temperature difference of 8°C correspond to 6.5 steps of feedforward value. The ambient temperature is 20℃ and the temperature difference is 2℃, corresponding to a feedforward value of 6 steps; the ambient temperature is 20℃ and the temperature difference is 4℃, corresponding to a feedforward value of 6.5 steps; the ambient temperature is 20℃ and the temperature difference is 6℃, corresponding to a feedforward value of 7 steps; the ambient temperature is 20℃ and the temperature difference is 8℃, corresponding to a feedforward value of 7.5 steps, and so on.

[0118] For example, the target air outlet temperature T airout，tar The actual air outlet temperature is 28℃. airout，act is 22℃, 28℃-22℃=6℃, and the temperature difference T is obtained airout，err By looking up Table 4, it can be determined that the feedforward value corresponding to the ambient temperature of 10°C and the temperature difference of 6°C is 5 steps.

[0119] After obtaining the feedforward value, the proportional value, integral value and feedforward value can be added together to obtain the target opening. The calculation formula is shown in the following formula (3):

[0120]

[0121] EXV_P in formula (3) pre is the feedforward value.

[0122] In the above method, the feedforward value is determined by the temperature difference between the actual outlet air temperature and the target outlet air temperature and the ambient temperature, and the feedforward value is incorporated into the control logic of the PI controller to improve the response speed of the air conditioning system. Feedforward control can compensate for changes in the working state of the air conditioning system in advance, reduce the accumulation of errors, thereby avoiding over-adjustment and oscillation, and enhancing the robustness and stability of the air conditioning system.

[0123] In step 105, after obtaining the target opening, the calculated target opening can be used as a control signal, and a control instruction including the control signal can be sent to an actuator of the electronic expansion valve (such as a stepper motor), so that the actuator can achieve precise opening control of the electronic expansion valve based on the control signal, thereby achieving regulation of the refrigerant flow and the actual exhaust pressure of the compressor.

[0124] In one possible implementation, before controlling the electronic expansion valve based on the target opening, the method also includes: processing the target opening based on a preset anti-shake opening and a preset rounding opening to obtain a processed target opening, so that the processed target opening is greater than or equal to the preset anti-shake opening and the processed target opening is an integer multiple of the preset rounding opening, wherein the preset rounding opening is smaller than the preset anti-shake opening; controlling the electronic expansion valve based on the target opening, including: controlling the electronic expansion valve based on the processed target opening.

[0125] The preset anti-shake opening is a pre-set minimum opening threshold for adjusting the electronic expansion valve, which is used to prevent the electronic expansion valve from frequently switching on and off (ie, "shaking") within a smaller opening range.

[0126] Processing the target opening based on the preset anti-shake opening includes: determining whether the target opening is less than the preset anti-shake opening; if the target opening is less than the preset anti-shake opening, adjusting the target opening to at least equal the preset anti-shake opening to avoid unnecessary small adjustments.

[0127] Exemplarily, the preset anti-shake opening is 10 steps, the target opening is 9 steps, and 9 steps is smaller than the preset anti-shake opening of 10 steps, then the target opening is adjusted to an opening greater than or equal to 10 steps, such as 10 steps, 11 steps, 12 steps, etc.

[0128] It is understandable that if the anti-shake processing is performed only on the target opening, usually when the target opening is smaller than the preset anti-shake opening, the target opening is adjusted to the size of the preset anti-shake opening.

[0129] The preset rounding opening is a fixed step size or increment set in advance, which is used to adjust the target opening to an integer multiple of the step size to reduce unnecessary fine-tuning of the electronic expansion valve when adjusting the target opening. The preset rounding opening is usually smaller than the preset anti-shake opening.

[0130] Processing the target opening based on the preset rounded opening includes: dividing the target opening by the preset rounded opening to obtain a target opening including multiples of the preset rounded opening, taking the integer multiple closest to the multiple, multiplying the integer multiple by the preset rounded opening, and obtaining the processed target opening.

[0131] Exemplarily, the preset rounded opening is 5 steps, the target opening is 12 steps, the target opening 12 steps divided by 5 steps, the multiple obtained is 2.4, the closest integer multiple of 2.4 is 2, the preset rounded opening 5 steps is multiplied by the integer multiple of 2, and the target opening is 10 steps.

[0132] When the target opening is processed based on the preset anti-shake opening and the preset rounding opening at the same time, the processed target opening must be greater than or equal to the preset anti-shake opening and be an integer multiple of the preset rounding opening.

[0133] Exemplarily, the preset anti-shake opening is 10 steps, the preset rounding opening is 5 steps, and the target opening is 9 steps. If 9 steps is smaller than the preset anti-shake opening of 10 steps, the target opening is adjusted to an opening greater than or equal to 10 steps, such as 10 steps, 11 steps, 12 steps, etc., wherein the minimum opening that is not smaller than the preset anti-shake opening and is an integer multiple of the preset rounding opening is 10, and the target opening is determined to be 10 steps.

[0134] In the above method, the target opening is processed based on the preset anti-shake opening, which avoids the frequent switching of the electronic expansion valve within a small opening range, reduces the jitter of the electronic expansion valve, reduces mechanical wear, and improves the stability of the system. The target opening is processed based on the preset rounded opening to ensure that the opening of the electronic expansion valve is always within the range that the system can accurately control, reduce unnecessary fine-tuning, and extend the service life of the electronic expansion valve components.

[0135] In one possible implementation, the electronic expansion valve is controlled based on a processed target opening, including: determining an opening difference according to the processed target opening and the current opening of the electronic expansion valve; determining an opening difference threshold based on a preset anti-shake opening; when the absolute value of the opening difference is greater than the opening difference threshold, determining an opening change rate corresponding to the opening difference, wherein the greater the absolute value of the opening difference, the greater the absolute value of the determined opening change rate; when the absolute value of the opening difference is less than or equal to the opening difference threshold, determining the opening change rate based on a preset rate; and controlling the electronic expansion valve based on the opening change rate.

[0136] The electronic expansion valve may be provided with a position sensor for measuring the actual opening of the electronic expansion valve. After obtaining the processed target opening, the actual opening of the electronic expansion valve measured by the position sensor is obtained to obtain the current opening.

[0137] The target opening after processing is still recorded as EXV_P cal , the current opening can be recorded as EXV_P current , the processed target opening EXV_P cal Subtract the current opening EXV_P current , get the opening difference, and record the opening difference as EXV_P err .

[0138] The process of determining the opening difference threshold based on the preset anti-shake opening is specifically as follows: the preset anti-shake opening is divided by the preset value to obtain the opening difference threshold. The preset value may be 2, 3, etc. Assuming the preset value is 2 and the preset anti-shake opening is 10 steps, the opening difference threshold = 10 / 2 = 5 steps.

[0139] It can be understood that the opening difference threshold is determined based on a preset anti-shake opening, and when the preset anti-shake opening is different, the determined opening difference threshold is also different.

[0140] Determine the relationship between the absolute value of the opening difference and the opening difference threshold. When it is determined that the absolute value of the opening difference is greater than the opening difference threshold, it can be determined that the electronic expansion valve needs to be adjusted more. At this time, the opening change rate corresponding to the opening difference is determined, wherein the larger the absolute value of the opening difference, the larger the absolute value of the determined opening change rate.

[0141] It can be understood that the opening difference between the target opening and the current opening can be positive or negative. When the opening difference is positive, the opening change rate determined based on the opening difference is the opening increase rate. When the opening difference is negative, the opening change rate determined based on the opening difference is the opening decrease rate.

[0142] Table 5

[0143]

[0144] As shown in Table 5, when the opening difference is positive, the adjustment range of the electronic expansion valve is 0 to 1000 (steps). When the opening difference is greater than the opening difference threshold 5, the opening increase rate gradually increases with the increase of the opening difference. Specifically, when the opening difference is in the range of (5,30], the corresponding opening increase rate is 5 steps / s; when the opening difference is in the range of (30,80], the corresponding opening increase rate is 10 steps / s; when the opening difference is in the range of (80,150], the corresponding opening increase rate is 15 steps / s; when the opening difference is in the range of (150,300], the corresponding opening increase rate is 20 steps / s; when the opening difference is in the range of (300,500], the corresponding opening increase rate is 25 steps / s; when the opening difference is in the range of (500,1000], the corresponding opening increase rate is 30 steps / s.

[0145] Table 6

[0146]

[0147] As shown in Table 6, when the opening difference is a negative value, the adjustment range of the electronic expansion valve is 0 to -1000 (steps). When the absolute value of the opening difference is greater than the opening difference threshold 5, the absolute value of the opening decrease rate gradually increases as the absolute value of the opening difference increases. Specifically, when the opening difference is in the range of [-30,-5), the corresponding opening decrease rate is -5 steps / s; when the opening difference is in the range of [-80,-30), the corresponding opening decrease rate is -10 steps / s; when the opening difference is in the range of [-150,-80), the corresponding opening decrease rate is -15 steps / s; when the opening difference is in the range of [-300,-150), the corresponding opening decrease rate is -20 steps / s; when the opening difference is in the range of [-500,-300), the corresponding opening decrease rate is -25 steps / s; when the opening difference is in the range of [-1000,-500), the corresponding opening decrease rate is -30 steps / s.

[0148] The above Table 5 and Table 6 can be stored in the air-conditioning system. When it is determined that the opening difference is greater than the opening difference threshold, Table 5 or Table 6 can be searched based on the opening difference to determine the opening increase rate or opening decrease rate corresponding to the opening difference to obtain the opening change rate.

[0149] Specifically, when the opening difference is a positive value, look up Table 5 and determine the opening increase rate corresponding to the opening difference based on Table 5; when the opening difference is a negative value, look up Table 6 and determine the opening decrease rate corresponding to the opening difference based on Table 6.

[0150] The preset rate is a fixed opening change rate set in advance, usually a positive value. If the opening difference is positive, when the absolute value of the opening difference is less than the opening threshold, the preset rate is determined as the opening increase rate. If the opening difference is negative, when the absolute value of the opening difference is less than the opening threshold, the negative value of the preset rate is determined as the opening decrease rate.

[0151] Exemplarily, the preset rate is 5 steps / s. When 0≤opening difference≤5, the opening increase rate can be determined to be 5 steps / s; when -5≤opening difference<0, the opening decrease rate can be determined to be -5 steps / s.

[0152] When the determined opening change rate is the opening increase rate, the opening of the electronic expansion valve is controlled to gradually increase based on the opening increase rate; when the determined opening change rate is the opening decrease rate, the opening of the electronic expansion valve is controlled to gradually decrease based on the opening decrease rate.

[0153] In the above method, when the absolute value of the opening difference between the target opening and the actual opening is greater than the opening difference threshold, a larger opening change rate is determined for a larger opening difference, which can ensure that the air-conditioning system responds quickly based on a larger opening change rate and achieves rapid adjustment. A smaller opening change rate is determined for a smaller opening difference, which can ensure that the air-conditioning system is slowly adjusted based on a smaller opening change rate to ensure system stability.

[0154] Figure 2 It is a flow chart of another method for controlling an electronic expansion valve provided in an embodiment of the present application.

[0155] For example, Figure 2 As shown, the method 200 includes:

[0156] Step 201, calculating the operating mode that the air conditioning system needs to operate according to the collected relevant sensor values ​​and user operation data;

[0157] The air conditioning system is specifically a carbon dioxide heat pump air conditioning system. The relevant sensor values ​​may include data such as the temperature in the vehicle and the humidity in the vehicle, and the user operation data may include data such as the target air outlet temperature and the target air outlet volume set by the user for the operation of the air conditioning system.

[0158] The process of calculating the working mode that the air-conditioning system needs to operate based on the relevant sensor values ​​and user operation data is as described in the above embodiment and will not be repeated here.

[0159] Step 202, determining whether the working mode is the target working mode; if so, executing step 203, if not, executing step 201;

[0160] The target working mode includes a cooling mode, a heating mode and a dehumidification mode. When the working mode is a shutdown mode or a ventilation mode, it can be determined that the working mode is not a target working mode.

[0161] Step 203, judging whether the air conditioning system needs a cold start based on the operating state of the air conditioning system; if yes, executing step 204, if no, executing step 206;

[0162] Among them, the operating status may include the interval between the current startup of the air-conditioning system and the last shutdown and the current external ambient temperature of the vehicle. When the interval is greater than the preset duration and / or the current external ambient temperature is lower than the preset temperature, it can be determined that the air-conditioning system needs a cold start, that is, in the above embodiment, it is determined that the air-conditioning system is in a cold start scenario.

[0163] Step 204, determining a fixed opening according to the current ambient temperature outside the vehicle, and performing a cold start based on the fixed opening;

[0164] Step 205, after the cold start preset time, determine whether the cold start is completed; if so, execute step 206, if not, execute step 204;

[0165] Step 206, entering the target working mode, selecting the corresponding optimal pressure calculation formula according to the target working mode, substituting the current refrigerant temperature into the optimal pressure calculation formula to obtain the optimal exhaust pressure;

[0166] The optimal pressure calculation formula corresponding to the current operation mode is selected, that is, the target constant and the target coefficient are determined according to the target operation mode and the current refrigerant temperature in the above embodiment. The optimal exhaust pressure is the target exhaust pressure.

[0167] Step 207, calculating the pressure difference between the actual exhaust pressure of the compressor and the optimal exhaust pressure, and calculating the temperature difference between the actual outlet air temperature of the air conditioning system and the target outlet air temperature;

[0168] Among them, the actual exhaust pressure of the compressor and the actual outlet air temperature of the air conditioning system are collected based on the corresponding sensors set.

[0169] Step 208, using the values ​​obtained by looking up the table of the ambient temperature outside the vehicle and the temperature difference as the feedforward value of the PI controller of the electronic expansion valve opening, and using the pressure difference as the control error of the PI controller;

[0170] Step 209, according to the target working mode, determine the proportional coefficient of the proportional term of the PI controller, then adjust the integral term to determine the integral coefficient, perform PI adjustment on the electronic expansion valve, and calculate the target opening of the electronic expansion valve;

[0171] Step 210, determining the opening change rate according to the opening difference between the target opening and the actual opening of the electronic expansion valve;

[0172] The opening difference includes positive and negative values, and the opening change rate includes an opening increase rate and an opening decrease rate. When the opening difference is a positive value, the determined opening change rate is the opening increase rate, and when the opening difference is a negative value, the determined opening change rate is the opening decrease rate.

[0173] When the absolute value of the opening difference is larger, the absolute value of the determined change rate is larger to ensure a quick response of the air-conditioning system. When the absolute value of the opening difference is smaller, the absolute value of the determined change rate is smaller to ensure the stability of the air-conditioning system.

[0174] Step 211, performing rounding and anti-shake processing on the target opening to obtain a processed target opening;

[0175] The target opening is rounded, that is, the target opening is processed to be an integer multiple of a preset rounded opening; the target opening is anti-shake processed, that is, the target opening is processed to be greater than or equal to a preset anti-shake opening value.

[0176] The detailed process of rounding and anti-shake processing the target opening is as described in the above embodiment, which will not be repeated here.

[0177] Step 212: output the processed target opening to the electronic expansion valve actuator to control the electronic expansion valve.

[0178] In summary, the present application calculates the target opening of the electronic expansion valve based on the pressure difference between the target exhaust pressure and the current actual exhaust pressure, and utilizes the performance control of the electronic expansion valve that the efficiency of the air conditioning system is greater than the preset efficiency threshold value when the target exhaust pressure exists in the transcritical cycle of the carbon dioxide heat pump air conditioning system, which can be better applied to the carbon dioxide heat pump air conditioning system, improve the performance of the carbon dioxide heat pump system, and reduce the energy consumption of the vehicle. The target opening is processed based on the preset anti-shake opening and the preset rounded opening, which avoids the frequent switching of the electronic expansion valve within a small opening range, reduces the jitter of the electronic expansion valve, reduces mechanical wear, reduces unnecessary fine-tuning, extends the service life of the electronic expansion valve components, and improves the stability of the system. For a larger opening difference, a larger opening change rate is determined, which can ensure that the air conditioning system responds quickly based on a larger opening change rate and achieves rapid adjustment. For a smaller opening difference, a smaller opening change rate is determined, which can ensure that the air conditioning system is slowly adjusted based on a smaller opening change rate, ensuring system stability. PI adjustment of the electronic expansion valve reduces the number of parameters that need to be adjusted compared to the PID controller, and reduces the complexity of parameter calibration. A fixed cold start opening is determined based on the ambient temperature to perform a cold start, ensuring that the air conditioning system has sufficient refrigerant flow at the initial cold start, thereby protecting the compressor and improving the stability of the system.

[0179] Figure 3 It is a structural schematic diagram of a device for controlling an electronic expansion valve provided in an embodiment of the present application.

[0180] For example, Figure 3 As shown, the device 300 includes:

[0181] The temperature acquisition module 301 is used to acquire the current refrigerant temperature at the outlet of the air cooler of the air conditioning system when the air conditioning system is in the target working mode;

[0182] The exhaust pressure calculation module 302 is used to determine the target exhaust pressure of the compressor of the air-conditioning system based on the target working mode and the current refrigerant temperature; wherein the efficiency of the air-conditioning system at the target exhaust pressure is greater than a preset efficiency threshold;

[0183] The pressure difference calculation module 303 is used to calculate the pressure difference between the target exhaust pressure and the current actual exhaust pressure of the compressor;

[0184] The target opening calculation module 304 is used to calculate the target opening of the electronic expansion valve according to the pressure difference;

[0185] The electronic expansion valve control module 305 is used to control the electronic expansion valve based on the target opening.

[0186] In one possible implementation, the exhaust pressure calculation module 302 is specifically used to determine a target coefficient and a target constant; wherein the target coefficient corresponds to the target operating mode and the current refrigerant temperature, and the target constant corresponds to the target operating mode and the current refrigerant temperature; the target coefficient is multiplied by the current refrigerant temperature to obtain an intermediate value; the intermediate value and the target constant are added to obtain the target exhaust pressure.

[0187] In one possible implementation, the device also includes: a processing module, used to process the target opening based on a preset anti-shake opening and a preset rounding opening to obtain a processed target opening, so that the processed target opening is greater than or equal to the preset anti-shake opening and the processed target opening is an integer multiple of the preset rounding opening, wherein the preset rounding opening is smaller than the preset anti-shake opening; the electronic expansion valve control module 305 is specifically used to control the electronic expansion valve based on the processed target opening.

[0188] In one possible implementation, the electronic expansion valve control module 305 is specifically used to determine the opening difference based on the processed target opening and the current opening of the electronic expansion valve; determine the opening difference threshold based on a preset anti-shake opening; when the absolute value of the opening difference is greater than the opening difference threshold, determine the opening change rate corresponding to the opening difference, wherein the larger the absolute value of the opening difference, the larger the absolute value of the determined opening change rate; when the absolute value of the opening difference is less than or equal to the opening difference threshold, determine the opening change rate based on the preset rate; and control the electronic expansion valve based on the opening change rate.

[0189] In one possible implementation, the target opening calculation module 304 is specifically used to determine the proportional coefficient and integral coefficient of the PI controller based on the target operating mode and the pressure difference; multiply the proportional coefficient by the pressure difference to obtain the proportional value; integrate the pressure difference based on the integral coefficient to obtain the integral value; and determine the target opening based on the proportional value and the integral value.

[0190] In one possible implementation, the device also includes: a feedforward value determination module, used to determine the target outlet air temperature corresponding to the target operating mode; calculate the temperature difference between the actual outlet air temperature of the air-conditioning system and the target outlet air temperature; based on the temperature difference and the current ambient temperature, determine the feedforward value of the PI controller; the target opening calculation module 304 is specifically used to add the proportional value, the integral value and the feedforward value to obtain the target opening.

[0191] In one possible implementation, the device also includes: a cold start module, which is used to determine whether the air-conditioning system is in a cold start scenario based on the operating status of the air-conditioning system when it is determined that the air-conditioning system needs to be started and operates based on a target operating mode; when it is determined that the air-conditioning system is in a cold start scenario, determine the cold start opening of the electronic expansion valve based on the current ambient temperature; based on the cold start opening, control the cold start of the air-conditioning system; when it is determined that the air-conditioning system has completed the cold start, control the air-conditioning system to enter the target operating mode.

[0192] Figure 4 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application.

[0193] For example, Figure 4 As shown, the electronic device 400 includes: a memory 401 and a processor 402, wherein the memory 401 stores an executable program code 4011, and the processor 402 is used to call and execute the executable program code 4011 to perform a method for controlling an electronic expansion valve.

[0194] In addition, an embodiment of the present application also protects a device, which may include a memory and a processor, wherein the memory stores an executable program code, and the processor is used to call and execute the executable program code to execute a method for controlling an electronic expansion valve provided in an embodiment of the present application.

[0195] In this embodiment, the functional modules of the device can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0196] In the case of dividing each functional module according to each function, the device may further include a temperature acquisition module, an exhaust pressure calculation module, a pressure difference calculation module, a target opening calculation module, and an electronic expansion valve control module, etc. It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, and will not be repeated here.

[0197] It should be understood that the device provided in this embodiment is used to execute the above-mentioned method for controlling an electronic expansion valve, and thus can achieve the same effect as the above-mentioned implementation method.

[0198] In the case of an integrated unit, the device may include a processing module and a storage module. When the device is applied to an electronic device, the processing module may be used to control and manage the actions of the electronic device. The storage module may be used to support the electronic device in executing relevant program codes, etc.

[0199] The processing module may be a processor or a controller, which may implement or execute various exemplary logic blocks, modules and circuits shown in conjunction with the disclosure of the present application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module may be a memory.

[0200] In addition, the device provided in the embodiments of the present application may specifically be a chip, a component or a module, and the chip may include a connected processor and a memory; wherein the memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute a method for controlling an electronic expansion valve provided in the above embodiments.

[0201] This embodiment also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is executed on a computer, the computer executes the above-mentioned related method steps to implement a method for controlling an electronic expansion valve provided in the above embodiment.

[0202] This embodiment further provides a computer program product. When the computer program product is run on a computer, the computer is enabled to execute the above-mentioned related steps to implement a method for controlling an electronic expansion valve provided in the above embodiment.

[0203] Among them, the device, computer-readable storage medium, computer program product or chip provided in this embodiment is used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, and will not be repeated here.

[0204] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0205] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0206] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for controlling an electronic expansion valve, characterized in that: The method comprises: When the air conditioning system is in a target working mode, obtaining a current refrigerant temperature at an air cooler outlet of the air conditioning system; Determining a target exhaust pressure of a compressor of the air-conditioning system based on the target operating mode and the current refrigerant temperature; wherein the efficiency of the air-conditioning system at the target exhaust pressure is greater than a preset efficiency threshold; Calculating a pressure difference between the target exhaust pressure and the current actual exhaust pressure of the compressor; Calculating a target opening of the electronic expansion valve according to the pressure difference; Based on the target opening degree, the electronic expansion valve is controlled.

2. The method according to claim 1, characterized in that The step of determining a target exhaust pressure of a compressor of the air conditioning system based on the target operating mode and the current refrigerant temperature includes: Determine a target coefficient and a target constant; wherein the target coefficient corresponds to the target operating mode and the current refrigerant temperature, and the target constant corresponds to the target operating mode and the current refrigerant temperature; Multiplying the target coefficient by the current refrigerant temperature to obtain an intermediate value; The target exhaust pressure is obtained by adding the intermediate value and the target constant.

3. The method according to claim 1 or 2, characterized in that: Before controlling the electronic expansion valve based on the target opening, the method further includes: Processing the target opening based on a preset anti-shake opening and a preset rounding opening to obtain a processed target opening, so that the processed target opening is greater than or equal to the preset anti-shake opening and the processed target opening is an integer multiple of the preset rounding opening, wherein the preset rounding opening is smaller than the preset anti-shake opening; The controlling the electronic expansion valve based on the target opening degree includes: The electronic expansion valve is controlled based on the processed target opening degree.

4. The method according to claim 3, characterized in that The controlling the electronic expansion valve based on the processed target opening degree includes: Determining an opening difference according to the processed target opening and the current opening of the electronic expansion valve; Determining an opening difference threshold based on the preset anti-shake opening; When the absolute value of the opening difference is greater than the opening difference threshold, determining the opening change rate corresponding to the opening difference, wherein the greater the absolute value of the opening difference is, the greater the absolute value of the determined opening change rate is; When the absolute value of the opening difference is less than or equal to the opening difference threshold, determining the opening change rate based on a preset rate; The electronic expansion valve is controlled based on the opening change rate.

5. The method according to claim 1 or 2, characterized in that: Calculating the target opening of the electronic expansion valve according to the pressure difference includes: Determining a proportional coefficient and an integral coefficient of a PI controller based on the target operating mode and the pressure difference; Multiplying the proportionality coefficient by the pressure difference to obtain a proportionality value; Integrating the pressure difference based on the integral coefficient to obtain an integral value; The target opening is determined according to the proportional value and the integral value.

6. The method according to claim 5, characterized in that When the air conditioning system is in the target operating mode, the method further includes: Determining a target air outlet temperature corresponding to the target operating mode; Calculating the temperature difference between the actual air outlet temperature of the air conditioning system and the target air outlet temperature; Determining a feedforward value of the PI controller based on the temperature difference and the current ambient temperature; Determining the target opening according to the proportional value and the integral value includes: The proportional value, the integral value and the feedforward value are added to obtain the target opening.

7. The method according to claim 1 or 2, characterized in that: Before obtaining the current refrigerant temperature at the air cooler outlet of the air conditioning system when the air conditioning system is in the target working mode, the method further includes: In the case where it is determined that the air-conditioning system needs to be started and operates based on the target working mode, judging whether the air-conditioning system is in a cold start scenario according to the operating state of the air-conditioning system; When it is determined that the air conditioning system is in the cold start scenario, determining the cold start opening degree of the electronic expansion valve based on the current ambient temperature; Based on the cold start opening degree, controlling the cold start of the air conditioning system; When it is determined that the air-conditioning system has completed the cold start, the air-conditioning system is controlled to enter the target working mode.

8. A device for controlling an electronic expansion valve, characterized in that: The device comprises: a temperature acquisition module, for acquiring a current refrigerant temperature at an air cooler outlet of the air conditioning system when the air conditioning system is in a target working mode; an exhaust pressure calculation module, configured to determine a target exhaust pressure of a compressor of the air-conditioning system based on the target operating mode and the current refrigerant temperature; wherein the efficiency of the air-conditioning system at the target exhaust pressure is greater than a preset efficiency threshold; A pressure difference calculation module, used to calculate the pressure difference between the target exhaust pressure and the current actual exhaust pressure of the compressor; A target opening calculation module, used for calculating the target opening of the electronic expansion valve according to the pressure difference; The electronic expansion valve control module is used to control the electronic expansion valve based on the target opening.

9. An electronic device, characterized in that: The electronic device comprises: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory, so that the electronic device executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the method according to any one of claims 1 to 7 is implemented.

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