Electronic expansion valve control method based on return air superheat degree and heat pump system

Abstract

The invention relates to an electronic expansion valve control method based on the return air superheat degree and a heat pump system. According to the control method, the return air superheat degree change value of the current valve adjusting period and the last valve adjusting period and the return air superheat degree deviation of the target return air superheat degree are calculated; the corresponding valve adjusting percentage is found out based on the return air superheat degree deviation and the return air superheat degree change value, the target opening degree of the next valve adjusting period is obtained based on the current valve opening degree of the electronic expansion valve and the valve adjusting percentage, and then the opening degree of the electronic expansion valve is adjusted. The opening degree of the electronic expansion valve meets the requirement for refrigerant mass flow, efficient and safe operation of the heat pump system is achieved, and the problems of evaporation performance reduction, system stability reduction, compressor liquid impact and the like are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump control, and in particular to an electronic expansion valve control method based on return air superheat and a heat pump system. Background Art

[0002] The heat pump system is an efficient and environmentally friendly energy utilization technology. Its core working principle is the reverse Carnot cycle. It transfers the heat energy in the low-temperature heat source to the high-temperature environment by consuming a small amount of electricity or other energy to achieve the purpose of heating or cooling. As a type of heat pump system, the air source heat pump system absorbs the low-temperature heat energy in the air with very little electricity, converts it into high-temperature heat energy after compression by the compressor, and then transmits it to the place where heating or cooling is required. It is highly favored by consumers and users and has been widely used in hotels, schools, hospitals, saunas, beauty salons, swimming pools, laundries and other places for refrigeration and hot water supply.

[0003] The same heat pump system has different refrigerant mass flow rates that enable the system to operate safely and efficiently under high ambient temperature and low ambient temperature conditions. The existing technology adjusts the opening of the PID electronic expansion valve according to the deviation between the return gas superheat and the target return gas superheat. When the difference between the return gas superheat and the target superheat is constant, the number of valve adjustment steps of the PID-controlled electronic expansion valve is constant, but for systems with high or low ambient temperatures, the same number of valve adjustment steps has a huge difference in the impact on the system. For example, the number of valve adjustment steps calculated by PID based on the return gas superheat deviation is 10 steps, but for the refrigerant system under high ambient temperature conditions, the impact is negligible, resulting in a low adjustment rate and a long time; but for the refrigerant system under low ambient temperature conditions, the impact is very large, which may cause liquid hammer problems in the system.

[0004] In the prior art, the electronic expansion valve of the heat pump system is adjusted according to the deviation between the return air superheat and the target return air superheat and the change value of the return air superheat. However, the method still adopts that a certain deviation corresponds to a certain number of steps, and a certain change value corresponds to a certain number of steps. The two are added together to calculate the valve adjustment steps of the electronic expansion valve. The above-mentioned high ambient temperature valve adjustment problem and low ambient temperature valve adjustment problem caused by the same valve adjustment steps when the same heat pump system works under high ambient temperature and low ambient temperature conditions also occur.

[0005] The above adjustment method does not take into account the huge difference in the impact of the same number of valve adjustment steps of the electronic expansion valve on the system under high ambient temperature and low ambient temperature conditions. Therefore, it is not possible to accurately control the opening of the electronic expansion valve to match the mass flow rate of the refrigerant with the frequency requirement of the compressor, resulting in the system experiencing problems such as decreased evaporation performance, decreased system stability, and compressor liquid hammer under low or high ambient temperature conditions. Summary of the invention

[0006] Based on this, the purpose of the present invention is to provide an electronic expansion valve control method based on return air superheat to solve the problem of mismatch between the opening adjustment of the electronic expansion valve and the system refrigerant mass flow demand under low ambient temperature and high ambient temperature conditions of the heat pump system.

[0007] A method for controlling an electronic expansion valve based on return air superheat comprises the following steps:

[0008] S10: collecting a number of return air temperatures and a number of low pressures of the refrigerant at a number of moments in the current valve regulating cycle, and calculating an average value of the return air superheat in the current valve regulating cycle;

[0009] S20: Calculate the difference between the average value of the return air superheat degree in the current valve regulating cycle and the average value of the return air superheat degree in the previous valve regulating cycle to obtain the return air superheat degree change value;

[0010] S30: Obtain target return air superheat, calculate the difference between the target return air superheat and the average return air superheat of the current valve adjustment cycle, and obtain the return air superheat deviation;

[0011] S40: determining the valve adjustment percentage of the next valve adjustment cycle according to the return air superheat change value and the return air superheat deviation in the valve adjustment percentage query table;

[0012] S50: Acquire the opening degree of the electronic expansion valve in the current valve regulation cycle, and calculate the target opening degree of the electronic expansion valve in the next valve regulation cycle according to the valve regulation percentage.

[0013] Furthermore, the mean value of the return air superheat degree in the current valve regulating cycle satisfies:

[0014]

[0015] In the formula, Indicates the average value of return air superheat in the current valve regulation cycle. represents the return air temperature collected at the kth sampling point, It represents the evaporation temperature corresponding to the low pressure collected at the kth sampling point, and n represents the total number of sampling points in the current valve regulation cycle.

[0016] Furthermore, the return air superheat change value satisfies:

[0017]

[0018] in,

[0019] Where, Δ(SSH t-1～t ) represents the change value of return air superheat, Indicates the average value of return air superheat in the previous valve adjustment cycle. Indicates the return air temperature collected at the kth sampling point in the previous valve adjustment cycle, Indicates the evaporation temperature corresponding to the low pressure collected at the kth sampling point in the previous valve adjustment cycle;

[0020] The return air superheat deviation satisfies:

[0021]

[0022] Where: Δ(SSH t ) represents the return air superheat deviation, SSH target Indicates the target return air superheat.

[0023] Furthermore, the valve adjustment percentage query table is an N*M-dimensional percentage value p ij matrix:

[0024]

[0025] Where i represents the return air superheat change value Δ(SSH t-1～t ) in the i-th range, i∈(1,N), the return air superheat change value Δ(SSH t-1～t ) has a total of N value ranges; j represents the return air superheat deviation Δ(SSH t ), j∈(1,M), the return gas superheat deviation Δ(SSH t )There are M value ranges in total.

[0026] Furthermore, the target opening degree K of the next valve adjustment cycle is t+1 satisfy:

[0027] K t+1 =K t *(100%-p ij )

[0028] In the formula, K t Indicates the opening degree of the electronic expansion valve in the current valve regulation cycle.

[0029] Furthermore, it also includes using the pressure difference correction factor to correct the valve adjustment percentage, and the target opening K of the next valve adjustment cycle t+1 satisfy:

[0030] K t+1 =K t *(100%-p ij *R)

[0031] in,

[0032] In the formula, Indicates the high pressure of the current valve adjustment cycle. Indicates the low pressure of the current valve adjustment cycle. It indicates the atmospheric pressure of the current valve regulating cycle, and R indicates the pressure difference correction factor.

[0033] Furthermore, it also includes using empirical constants to correct the pressure adjustment percentage, and the target opening K of the next valve adjustment cycle t+1 satisfy:

[0034] K t+1 =K t *(100%-p ij *R*α)

[0035] In the formula, α represents an empirical constant.

[0036] Compared with the prior art, the present invention calculates the return air superheat change value between the current valve adjustment cycle and the previous valve adjustment cycle, and the return air superheat deviation from the target return air superheat, and finds out the corresponding valve adjustment percentage based on the return air superheat deviation and the return air superheat change value, and obtains the target opening of the next valve adjustment cycle based on the current valve opening of the electronic expansion valve and the valve adjustment percentage, and then adjusts the opening of the electronic expansion valve, so that when the heat pump is running at high ambient temperature and low ambient temperature, the opening of the electronic expansion valve meets the refrigerant mass flow requirement, thereby achieving efficient and safe operation of the heat pump system and avoiding problems such as decreased evaporation performance, decreased system stability, and compressor liquid hammer; at the same time, the pressure difference correction factor and the empirical constant are used to correct the valve adjustment percentage, which can further improve the adjustment accuracy of the electronic expansion valve under high ambient temperature and low ambient temperature conditions, and better match the refrigerant mass flow required by the system.

[0037] Meanwhile, the invention also provides a heat pump system.

[0038] A heat pump system comprises a compressor, a four-way valve, a water-side heat exchanger, an electronic expansion valve, an air-side heat exchanger, and a sensor module connected in sequence through a refrigerant circulation pipeline, and a controller electrically and / or communicatively connected to the electronic expansion valve and the sensor module, wherein the controller comprises: a return air superheat average value calculation unit, a return air superheat variation value calculation unit, a return air superheat deviation calculation unit, a valve adjustment percentage query unit, and a valve opening calculation unit:

[0039] The return air superheat average value calculation unit is used to collect a number of return air temperatures and a number of low pressures of the refrigerant at a number of moments in the current valve regulation cycle, and calculate the return air superheat average value of the current valve regulation cycle;

[0040] The return air superheat change value calculation unit is used to calculate the difference between the return air superheat mean value of the current valve adjustment cycle and the return air superheat mean value of the previous valve adjustment cycle to obtain the return air superheat change value;

[0041] The return air superheat deviation calculation unit is used to calculate the difference between the target return air superheat and the average return air superheat of the current valve adjustment cycle to obtain the return air superheat deviation;

[0042] The valve adjustment percentage query unit is used to determine the valve adjustment percentage of the next valve adjustment cycle according to the return air superheat change value and the return air superheat deviation in the valve adjustment percentage query table;

[0043] The valve opening calculation unit is used to obtain the opening of the electronic expansion valve in the current valve regulation cycle, and calculate the target opening of the electronic expansion valve in the next valve regulation cycle according to the valve regulation percentage.

[0044] Furthermore, the controller further comprises a pressure difference correction unit:

[0045] The pressure difference correction unit is used to obtain the high pressure in the current valve adjustment cycle. Calculate the pressure difference correction factor R and use the pressure difference correction factor to adjust the valve percentage p ij Make corrections.

[0046] Furthermore, the controller also includes an empirical constant correction unit:

[0047] The empirical constant correction unit is used to obtain the empirical constant α of the system and use the empirical constant α to adjust the valve percentage p ij Make corrections.

[0048] The beneficial effects of the heat pump system proposed in the present invention are the same as those of the above-mentioned electronic expansion valve control method based on return air superheat, and will not be described in detail here.

[0049] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A schematic diagram of the system structure of an embodiment of the present invention;

[0051] Figure 2 The figure is a flow chart of an electronic expansion valve control method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention.

[0053] In order to solve the problem that under low ambient temperature and high ambient temperature conditions, when the valve adjustment value corresponding to the deviation between the return air superheat and the target return air superheat, and / or the valve adjustment value corresponding to the change value of the return air superheat is used in the prior art to adjust the opening of the electronic expansion valve, the same valve adjustment step number cannot take into account the influence of low ambient temperature and high ambient temperature on the refrigerant mass flow rate in the system, resulting in the inability to accurately control the opening of the electronic expansion valve to match the mass flow rate of the refrigerant with the frequency requirement of the compressor, causing the system to experience problems such as decreased evaporation performance, decreased system stability, and compressor liquid hammer under low ambient temperature or high ambient temperature conditions. The present invention proposes an electronic expansion valve control method based on return air superheat A control method is provided, wherein the control method calculates the return air superheat change value between the current valve adjustment cycle and the previous valve adjustment cycle, and the return air superheat deviation from the target return air superheat, and finds out the corresponding valve adjustment percentage based on the return air superheat deviation and the return air superheat change value, obtains the target opening of the next valve adjustment cycle based on the current valve opening of the electronic expansion valve and the valve adjustment percentage, and then adjusts the opening of the electronic expansion valve, so that when the heat pump is operating at high ambient temperature and low ambient temperature, the opening of the electronic expansion valve meets the demand of the refrigerant mass flow rate, realizes efficient and safe operation of the heat pump system, and avoids problems such as reduced evaporation performance, reduced system stability, and compressor liquid hammer.

[0054] For specific implementation, please refer to Figure 1 The heat pump system proposed in the present invention includes a compressor 10, a four-way valve 20, a water-side heat exchanger 30, an electronic expansion valve 40, an air-side heat exchanger 50, a sensor module 60, a controller (not shown), and other auxiliary pipes connected through a refrigerant pipeline. The controller is electrically connected and / or communicatively connected to the electronic expansion valve 40 and the sensor module 60.

[0055] The sensor module 60 includes a temperature sensor 61 , a first pressure sensor 62 , a second pressure sensor 63 , and a third pressure sensor 64 .

[0056] The temperature sensor 61 is arranged at the return air port of the compressor 10 to collect the return air temperature of the refrigerant. The measured return air temperature transmitted to the controller.

[0057] The first pressure sensor 61 is disposed at the exhaust port of the compressor 10 and is used to collect the high pressure of the refrigerant. The measured high pressure transmitted to the controller.

[0058] The second pressure sensor 62 is disposed at the return air port of the compressor 10 and is used to collect the low pressure of the refrigerant. And the measured low pressure transmitted to the controller.

[0059] The controller includes a return gas superheat average value calculation unit 100 , a return gas superheat variation value calculation unit 200 , a return gas superheat deviation calculation unit 300 , a valve adjustment percentage query unit 400 , and a valve opening calculation unit 500 .

[0060] The return air superheat average value calculation unit 100 is used to execute step S10: collect several return air temperatures of the refrigerant at several moments in the current valve adjustment cycle and several low pressure According to several low pressure Determine the evaporation temperatures corresponding to the refrigerant According to the return air temperature and several evaporation temperatures Calculate the average return air superheat value of the current valve adjustment cycle

[0061]

[0062] Where k represents the kth sampling point in the current valve regulation cycle, n represents the total number of sampling points in the current valve regulation cycle, and t represents the valve regulation cycle, such as 10 seconds, 20 seconds, 30 seconds, etc.

[0063] The duration of the valve regulation cycle and the number of sampling points within the valve regulation cycle are set as needed. The time intervals between sampling points can be set to be equal, to have trend changes, or to be random, and this application does not impose any restrictions.

[0064] Example 1: The valve regulation cycle is set to 30 seconds, that is, the average return air superheat within the valve regulation cycle is calculated every 30 seconds; the return air temperature and low pressure are collected once every 3 seconds, and there are 10 sampling points in total, that is, the average return air superheat is equal to the average value calculated from the data of the 10 sampling points.

[0065] According to several low pressure Determine several evaporation temperatures corresponding to the refrigerant The method may adopt a table lookup method or a formula calculation method, and this application does not make any limitation.

[0066] The return air superheat change value calculation unit 200 is used to execute step S20: calculate the return air superheat mean value of the current valve adjustment cycle The average value of return air superheat in the previous valve adjustment cycle The difference between the return air superheat change Δ(SSH t-1～t ).

[0067] The average return air superheat value SSH of the previous valve adjustment cycle t-1 The return air superheat average value calculation unit 100 calculates:

[0068]

[0069] Return air superheat change value satisfy:

[0070]

[0071] The return air superheat deviation calculation unit 300 is used to execute step S30: obtain the target return air superheat SSH target , calculate the target return air superheat SSH target The average value of return air superheat during the current valve adjustment cycle The difference between the return air superheat deviation Δ(SSH t ).

[0072] Return air superheat deviation Δ(SSH t )satisfy:

[0073]

[0074] The valve adjustment percentage query unit 400 is used to execute step S40: in the valve adjustment percentage query table, according to the return gas superheat change value Δ(SSH t-1～t ) and return gas superheat deviation Δ(SSH t ) Determine the valve adjustment percentage p of the next valve adjustment cycle ij , where i represents the i-th value range interval of the return gas superheat change value, j represents the j-th value range interval of the return gas superheat deviation, i∈(1,N), j∈(1,M).

[0075] The valve adjustment percentage query table P is an N*M-dimensional percentage value p ij Matrix, where: the row labels are the value ranges of the return air superheat change value, there are N value ranges in total, that is, N rows; the column labels are the value ranges of the return air superheat deviation, there are M value ranges in total, that is, M columns.

[0076] The valve adjustment percentage query table P is expressed as:

[0077]

[0078] The valve adjustment percentage query table adjusts the electronic expansion valve to make the refrigerant mass flow of the heat pump system meet the return air superheat change value and the return air superheat deviation tested when the system is running efficiently and safely, according to the valve adjustment percentage corresponding to the high ambient temperature and low ambient temperature of the heat pump.

[0079] Example 2: Return air superheat change Δ(SSH t-1～t ) has five value ranges, namely, (, -2], (-2, -1), [-1, 1], (1, 2), [2,); the return gas superheat deviation Δ (SSH t) has 5 value ranges, namely (, -2], (-2, -1), [-1, 1], (1, 2), [2,); then the corresponding valve adjustment percentage query table has 5*5=25 percentage values ​​p, see Table 1.

[0080] Table 1

[0081]

[0082]

[0083] The valve opening calculation unit 500 is used to execute step S50: obtain the opening K of the electronic expansion valve in the current valve adjustment cycle. t , according to the valve adjustment percentage p ij Calculate the target opening degree K of the next valve adjustment cycle of the electronic expansion valve t+1 .

[0084] The target opening degree K of the next valve adjustment cycle t+1 satisfy:

[0085] K t+1 =K t *(100%-p ij ).

[0086] Since different water temperatures will also have a certain impact under the same ambient temperature, the higher the water temperature, the greater the system pressure difference. Under the same opening of the electronic expansion valve, the greater the system pressure difference, the greater the refrigerant mass flow rate. Therefore, in order to improve the adjustment accuracy of the electronic expansion valve under high and low ambient temperature conditions, in one embodiment, the system pressure difference is used to adjust the valve percentage p ij Make corrections.

[0087] The controller further includes a pressure difference correction unit 600 for executing step S60: obtaining the high pressure in the current valve adjustment cycle Calculate the pressure difference correction factor R and use the pressure difference correction factor to adjust the valve percentage p ij Make corrections.

[0088] The pressure difference correction factor R satisfies:

[0089]

[0090] in, Indicates the atmospheric pressure of the current valve adjustment cycle.

[0091] Then the target opening degree K of the next valve adjustment cycle after pressure difference correction is t+1 satisfy:

[0092] K t+1 =K t *(100%-p ij *R).

[0093] Since other factors such as various components of the system also have a certain influence under the same ambient temperature and the same water temperature, in one embodiment, a correction coefficient is used to characterize the influence of other factors besides the ambient temperature and the water temperature on the opening of the electronic expansion valve.

[0094] The controller further includes an empirical constant correction unit 700, which is used to execute step S70: obtaining the empirical constant α of the system, and using the empirical constant α to adjust the valve percentage p ij Make corrections.

[0095] Then the target opening K of the next valve adjustment cycle after pressure difference correction and empirical constant correction is t+1 satisfy:

[0096] K t+1 =K t *(100%-p ij *R*α).

[0097] Example 3: When the heat pump system is running at a high ambient temperature, a large refrigerant mass flow is required, so the opening of the electronic expansion valve is relatively large. According to Table 1, it is known that the valve needs to be opened by 2%. Assuming that the current ambient temperature is 20 degrees, the opening of the electronic expansion valve is 400Pulse, the pressure difference correction factor R=1, and the empirical constant α=1, the valve is opened at the current 2%, and 8 steps of valves are opened; when the heat pump system is running at a low ambient temperature, a small refrigerant mass flow is required, so the opening of the electronic expansion valve is relatively small. Assuming that the current ambient temperature is -20 degrees, the opening of the electronic expansion valve is 100Pulse, the pressure difference correction factor R=1, and the empirical constant α=1, the valve is opened at the current 2%, and 2 steps of valves are opened. It can be seen that adjusting the valve according to the opening of the electronic expansion valve itself and the percentage of its own opening can better take into account the opening requirements of the electronic expansion valve at high and low ambient temperatures.

[0098] Using the pressure difference correction factor and empirical constant to correct the valve adjustment percentage can further improve the adjustment accuracy of the electronic expansion valve under high and low ambient temperature conditions, and better match it with the refrigerant mass flow required by the system.

[0099] In a specific implementation, the controller is an electronic device, which includes but is not limited to: a memory, a processor, and a network interface that can be interconnected and communicated via a system bus.

[0100] The electronic device may be a computing device such as a rack server, a blade server, a tower server or a cabinet server.

[0101] The memory includes at least one type of readable storage medium, and the readable storage medium includes flash memory, hard disk, multimedia card, card-type memory (for example, SD or DX memory, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disk, etc. The memory can be an internal storage unit of the electronic device, such as a hard disk or memory of the electronic device. The memory can also be an external storage device of the electronic device, such as a plug-in hard disk equipped on the electronic device, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. The memory can also include both the internal storage unit of the electronic device and its external storage device.

[0102] The processor may be a central processing unit (CPU), a microcontroller, a microprocessor, or other data processing chip. The processor is generally used to control the overall operation of the electronic device, such as executing control and processing related to data interaction or communication with the electronic device. The processor is used to run the program code stored in the memory or process data, such as running the electronic expansion valve control method based on return gas superheat, etc.

[0103] The network interface may include a wireless network interface or a wired network interface, which is generally used to establish a communication connection between the electronic device and other electronic devices. For example, the network interface is used to connect the electronic device to an external data platform through a network, and to establish a data transmission channel and a communication connection between the electronic device and the external data platform. The network may be an intranet, the Internet, a global system of mobile communications (GSM), a wideband code division multiple access (WCDMA), a 4G network, a 5G network, Bluetooth, a Wi-Fi or other wireless or wired network.

[0104] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that, unless otherwise specified, "multiple" and "several" refer to two or more; "and / or" refers to and includes any or all possible combinations of one or more associated listed items; "first", "second", "third", etc. are only used to distinguish, rather than to describe a specific order or sequence, and cannot be understood as indicating or implying relative importance. When the above description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of the present application, for those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0105] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and the present invention is also intended to include these modifications and modifications.

Claims

1. An electronic expansion valve control method based on return air superheat, characterized in that: include: S10: collecting a number of return air temperatures and a number of low pressures of the refrigerant at a number of moments in the current valve regulating cycle, and calculating an average value of the return air superheat in the current valve regulating cycle; S20: Calculate the difference between the average value of the return air superheat degree in the current valve regulating cycle and the average value of the return air superheat degree in the previous valve regulating cycle to obtain the return air superheat degree change value; S30: Obtain target return air superheat, calculate the difference between the target return air superheat and the average return air superheat of the current valve adjustment cycle, and obtain the return air superheat deviation; S40: determining the valve adjustment percentage of the next valve adjustment cycle according to the return air superheat change value and the return air superheat deviation in the valve adjustment percentage query table; S50: Acquire the opening degree of the electronic expansion valve in the current valve regulation cycle, and calculate the target opening degree of the electronic expansion valve in the next valve regulation cycle according to the valve regulation percentage.

2. The electronic expansion valve control method according to claim 1, characterized in that: The average value of the return air superheat in the current valve adjustment cycle satisfies: In the formula, Indicates the average value of return air superheat in the current valve regulation cycle. represents the return air temperature collected at the kth sampling point, It represents the evaporation temperature corresponding to the low pressure collected at the kth sampling point, and n represents the total number of sampling points in the current valve regulation cycle.

3. The electronic expansion valve control method according to claim 2, characterized in that: The return air superheat change value satisfies: in, Where, Δ(SSH t-1～t ) represents the change value of return air superheat, Indicates the average value of return air superheat in the previous valve adjustment cycle. Indicates the return air temperature collected at the kth sampling point in the previous valve adjustment cycle, Indicates the evaporation temperature corresponding to the low pressure collected at the kth sampling point in the previous valve adjustment cycle; The return air superheat deviation satisfies: Where: Δ(SSH t ) represents the return air superheat deviation, SSH target Indicates the target return air superheat.

4. The electronic expansion valve control method according to claim 3, characterized in that: The valve adjustment percentage query table is an N*M-dimensional percentage value p ij matrix: Where i represents the return air superheat change value Δ(SSH t-1～t ) in the i-th range, i∈(1,N), the return gas superheat change value Δ(SSH t-1～t ) has a total of N value ranges; j represents the return air superheat deviation Δ(SSH t ), j∈(1,M), the return gas superheat deviation Δ(SSH t )There are M value ranges in total.

5. The electronic expansion valve control method according to claim 4, characterized in that: The target opening degree K of the next valve adjustment cycle t+1 satisfy: K t+1 =K t *(100%-p ij ) In the formula, K t Indicates the opening degree of the electronic expansion valve in the current valve regulation cycle.

6. The electronic expansion valve control method according to claim 5, characterized in that: It also includes using the pressure difference correction factor to correct the valve adjustment percentage, and the target opening K of the next valve adjustment cycle t+1 satisfy: K t+1 =K t *(100%-p ij *R) in, In the formula, Indicates the high pressure of the current valve adjustment cycle. Indicates the low pressure of the current valve adjustment cycle. It indicates the atmospheric pressure of the current valve regulating cycle, and R indicates the pressure difference correction factor.

7. The electronic expansion valve control method according to claim 6, characterized in that: It also includes using empirical constants to correct the pressure adjustment percentage, and the target opening K of the next valve adjustment cycle t+1 satisfy: K t+1 =K t *(100%-p ij *R*a) In the formula, α represents an empirical constant.

8. A heat pump system, comprising a compressor, a four-way valve, a water-side heat exchanger, an electronic expansion valve, an air-side heat exchanger, and a sensor module connected in sequence through a refrigerant circulation pipeline, and a controller electrically and / or communicatively connected to the electronic expansion valve and the sensor module, characterized in that: The controller includes: a return gas superheat mean value calculation unit, a return gas superheat change value calculation unit, a return gas superheat deviation calculation unit, a valve adjustment percentage query unit, and a valve opening calculation unit: The return air superheat average value calculation unit is used to collect a number of return air temperatures and a number of low pressures of the refrigerant at a number of moments in the current valve regulation cycle, and calculate the return air superheat average value of the current valve regulation cycle; The return air superheat change value calculation unit is used to calculate the difference between the return air superheat mean value of the current valve adjustment cycle and the return air superheat mean value of the previous valve adjustment cycle to obtain the return air superheat change value; The return air superheat deviation calculation unit is used to calculate the difference between the target return air superheat and the average return air superheat of the current valve adjustment cycle to obtain the return air superheat deviation; The valve adjustment percentage query unit is used to determine the valve adjustment percentage of the next valve adjustment cycle according to the return air superheat change value and the return air superheat deviation in the valve adjustment percentage query table; The valve opening calculation unit is used to obtain the opening of the electronic expansion valve in the current valve regulation cycle, and calculate the target opening of the electronic expansion valve in the next valve regulation cycle according to the valve regulation percentage.

9. The heat pump system according to claim 8, characterized in that: The controller also includes a pressure difference correction unit: The pressure difference correction unit is used to obtain the high pressure in the current valve adjustment cycle. Calculate the pressure difference correction factor R and use the pressure difference correction factor to adjust the valve percentage p ij Make corrections.

10. The heat pump system according to claim 9, characterized in that: The controller also includes an empirical constant correction unit: The empirical constant correction unit is used to obtain the empirical constant α of the system and use the empirical constant α to adjust the valve percentage p ij Make corrections.

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