Control Method and Device of Heat Pump Equipment, Readable Storage Medium and Heat Pump Equipment

Abstract

The present invention provides a control method and device for a heat pump device, a readable storage medium, and a heat pump device. The method includes: in a defrosting mode, in response to a defrosting end signal, obtaining the outlet water temperature of the heat pump device and the first opening degree of an expansion valve; determining a corresponding coefficient according to the outlet water temperature; determining a second opening degree according to the first opening degree and the coefficient; and controlling the expansion valve to adjust the opening degree according to the second opening degree. By determining the corresponding coefficient based on the real-time outlet water temperature, determining the second opening degree that matches the outlet water temperature according to the coefficient and the first opening degree, and adjusting the opening degree of the expansion valve when exiting the defrosting mode based on the second opening degree, it is possible to ensure an appropriate pressure difference in the refrigerant system, avoid the problems of insufficient liquid supply and low suction pressure on the one hand, and avoid the problem of excessive liquid supply on the other hand, and effectively improve the operating efficiency and reliability of the heat pump device.

Description

Technical Field

[0001] The present invention relates to the technical field of air source heat pumps, and in particular, to a control method and device for a heat pump device, a readable storage medium, and a heat pump device. Background Art

[0002] In the related art, when an air source heat pump operates in the heating mode, frost will form on the outdoor heat exchange fins and defrosting is required. Since the defrosting process is a non-steady-state short-time process, when exiting defrosting, it switches from the refrigeration operation to the heating operation instantaneously. At this time, the electronic expansion valve returns to the opening degree before defrosting. However, if the operating conditions before defrosting are inconsistent with those after defrosting, it may lead to a low suction pressure or an excessive liquid supply, affecting the operation of the system. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related technologies.

[0004] To this end, a first aspect of the present invention provides a control method for a heat pump device.

[0005] A second aspect of the present invention provides a control device for a heat pump device.

[0006] A third aspect of the present invention provides another control device for a heat pump device.

[0007] A fourth aspect of the present invention provides a readable storage medium.

[0008] A fifth aspect of the present invention provides a heat pump device.

[0009] In view of this, a first aspect of the present invention provides a control method for a heat pump device. The heat pump device includes an expansion valve. The method includes: in the defrost mode, in response to a defrost end signal, obtaining the outlet water temperature of the heat pump device and the first opening degree of the expansion valve; determining a corresponding coefficient according to the outlet water temperature; determining a second opening degree according to the first opening degree and the coefficient; and controlling the expansion valve to adjust the opening degree according to the second opening degree.

[0010] In this technical solution, the heat pump device may specifically be an air source heat pump unit, and the heat pump device includes a throttling component, such as an expansion valve. When the heat pump device operates in the heating mode, the temperature of the outdoor heat exchanger is relatively low, and at this time, frost may form on the outdoor heat exchanger. The frost will cause a serious decline in the heat exchange efficiency of the outdoor heat exchanger, so defrosting is required.

[0011] In the defrost mode, the four-way valve of the heat pump device changes direction, that is, it is equivalent to controlling the heat pump device to switch from the heating mode to the refrigeration mode within a short time, and the frost condensed on the outdoor heat exchanger is melted by raising the temperature of the outdoor heat exchanger, thereby achieving defrosting.

[0012] When the heat pump device is in the defrosting mode, if a defrosting end signal is received, that is, the heat pump device is about to exit the defrosting mode and resume normal heating mode operation, the control device of the heat pump device collects the current outlet water temperature of the heat pump device at this time and obtains the first opening degree corresponding to the expansion valve. Among them, the first opening degree is specifically the opening degree of the heat pump device before entering the defrosting mode.

[0013] According to the current outlet water temperature, determine the corresponding coefficient. Among them, this coefficient is used to adjust the first opening degree, that is, to adjust the opening degree of the expansion valve before entering the defrosting mode, so as to obtain the second opening degree, and adjust the opening degree of the expansion valve based on the second opening degree, so as to exit the defrosting mode.

[0014] Specifically, the above coefficient is related to the outlet water temperature, and the outlet water temperature is related to the exhaust pressure of the compressor in the heat pump device. Among them, if the outlet water temperature is low, it can be determined that the exhaust pressure is low, so the pressure difference of the refrigerant system will also be relatively low. At this time, if the opening degree of the expansion valve is insufficient, it may lead to insufficient liquid supply and too low suction pressure. If the outlet water temperature is high, it can be determined that the exhaust pressure is high, and the pressure difference of the refrigerant system will also be relatively high. At this time, if the opening degree of the expansion valve is too high, it may lead to excessive liquid supply and liquid carrying phenomenon.

[0015] Therefore, by determining the corresponding coefficient based on the real-time outlet water temperature, determining the second opening degree matching the outlet water temperature according to the coefficient and the first opening degree, and adjusting the opening degree of the expansion valve when exiting the defrosting mode based on the second opening degree, it can ensure that the pressure difference of the refrigerant system is appropriate. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operation efficiency and operation reliability of the heat pump device.

[0016] In addition, the control method of the heat pump device in the above technical solution provided by the present invention may also have the following additional technical features:

[0017] In the above technical solution, determining the corresponding coefficient according to the outlet water temperature includes: obtaining preset parameters; calculating the coefficient through the coefficient formula, parameters and outlet water temperature.

[0018] In this technical solution, when determining the coefficient corresponding to the outlet water temperature, the real-time outlet water temperature of the heat pump device and the preset parameters can be brought into the coefficient formula through the preset parameters and the preset coefficient formula, so as to calculate the corresponding coefficient through the coefficient formula. Based on the obtained coefficient and the first opening degree of the expansion valve before the defrosting mode, determine the second opening degree matching the outlet water temperature, and adjust the opening degree of the expansion valve when exiting the defrosting mode based on the second opening degree, which can ensure that the pressure difference of the refrigerant system is appropriate, prevent the problems of too low suction pressure or excessive liquid supply from occurring, ensure the operation reliability of the heat pump device, and ensure the stability of the defrosting mode.

[0019] In any of the above technical solutions, the coefficient formula includes:

[0020] K1 = a × lwt 2 – b × lwt + c

[0021] Wherein, K1 is the coefficient, lwt is the outlet water temperature, and a, b, and c are parameters.

[0022] In this technical solution, the preset parameters specifically include the first parameter a, the second parameter b, and the third parameter c. Among them, the first parameter a, the second parameter b, and the third parameter c are all fitting coefficients, and the first parameter a, the second parameter b, and the third parameter c are constants.

[0023] When calculating the coefficient matching the outlet water temperature, calculate the square value of the outlet water temperature, calculate the first product of the first parameter a and this square value, further calculate the second product of the second parameter b and the outlet water temperature, calculate the difference between the first product and the second product, and then add the third parameter c. The final sum obtained is the above coefficient K1.

[0024] It can be seen from the coefficient formula that the coefficient K1 is only related to the outlet water temperature lwt. Based on the outlet water temperature lwt, the corresponding coefficient K1 is determined. According to the coefficient K1 and the first opening degree, the second opening degree is further determined. By controlling the expansion valve to adjust the opening degree when exiting the defrosting mode through the second opening degree, it is possible to avoid too low suction pressure or too much liquid supply, and ensure the operation stability of the heat pump device.

[0025] In any of the above technical solutions, determining the second opening degree according to the first opening degree and the coefficient includes: calculating the product of the first opening degree and the coefficient, and determining it as the second opening degree.

[0026] In this technical solution, the second opening degree Openness2 is determined by the product of the first opening degree Openness1 and the coefficient K1.

[0027] Specifically, it is calculated by the following formula:

[0028] Openness2 = Openness1 × K1

[0029] Wherein, since the coefficient K1 is related to the outlet water temperature lwt, based on the outlet water temperature lwt, the corresponding coefficient K1 is determined. According to the coefficient K1 and the first opening degree Openness1, the second opening degree Openness2 is further determined. By controlling the expansion valve to adjust the opening degree to exit the defrosting mode through the second opening degree Openness2, it is possible to prevent problems such as too low suction pressure or too much liquid supply from occurring, and improve the operation reliability of the heat pump device.

[0030] In any of the above technical solutions, controlling the expansion valve to adjust its opening degree according to the second opening degree includes: obtaining the minimum opening degree of the expansion valve; controlling the opening degree of the expansion valve to be adjusted to the larger value between the second opening degree and the minimum opening degree.

[0031] In this technical solution, the above-mentioned minimum opening degree is specifically the lower limit of the opening degree that the expansion valve is allowed to adjust on the premise of ensuring the suction pressure and liquid supply required when exiting the defrosting mode under the condition that the opening degree of the expansion valve is too small before entering the defrosting mode. Therefore, when controlling the expansion valve to adjust its opening degree during the stage of exiting defrosting, in order to ensure the stable operation of the heat pump system, the real-time opening degree of the adjusted expansion valve should not be less than this minimum opening degree.

[0032] Therefore, when adjusting the opening degree of the expansion valve to adapt to the stage of exiting the defrosting mode, the larger opening degree between the second opening degree and the above-mentioned minimum opening degree is used as the target opening degree, and the opening degree of the expansion valve is controlled to be adjusted to the target opening degree.

[0033] Specifically, if the opening degree value of the second opening degree is greater than the opening degree value of the minimum opening degree, then control the expansion valve to adjust the current opening degree to the second opening degree. On the contrary, if the opening degree value of the second opening degree is less than or equal to the opening degree value of the minimum opening degree, then control the expansion valve to adjust the current opening degree to the minimum opening degree, so as to ensure the operation reliability of the heat pump device.

[0034] In any of the above technical solutions, the heat pump device further includes a four-way valve. Before responding to the defrosting end signal, the control method further includes: responding to the defrosting start signal, recording the first opening degree, and controlling the four-way valve to change its direction.

[0035] In this technical solution, for heat pump devices such as air-source heat pump systems, when they are operating in the heating mode, since the outdoor heat exchanger needs to absorb heat from the external environment, the temperature of the outdoor heat exchanger is relatively low, generally lower than 0°C. Therefore, if the humidity of the external environment is relatively high, it will cause frosting on the outdoor heat exchanger, affecting the heating effect. At this time, defrosting of the outdoor heat exchanger is required.

[0036] When it is detected that the outdoor heat exchanger is frosted and defrosting is required, the control system of the heat pump device generates a defrosting start signal. After receiving the defrosting start signal, the heat pump device controls the four-way valve to change its direction. At this time, it is equivalent to switching the heat pump device from the heating mode to the cooling mode. When the four-way valve changes its direction, the temperature of the outdoor heat exchanger will rise, and the frost on the outdoor heat exchanger is melted by releasing heat to achieve defrosting.

[0037] Before controlling the four-way valve to perform commutation, record the first opening degree of the expansion valve before entering the defrosting mode, and when the heat pump device exits the defrosting mode, determine the second opening degree for adjusting the opening degree of the expansion valve when exiting the defrosting mode according to the first opening degree and the coefficient calculated based on the outlet water temperature, so as to ensure the operation reliability and stability of the heat pump device.

[0038] In any of the above technical solutions, after controlling the expansion valve to adjust the opening degree, the method further includes: controlling the four-way valve to commutate again and maintaining the opening degree of the expansion valve within a preset time period.

[0039] In this technical solution, when exiting the defrosting mode, the four-way valve performs commutation, which is equivalent to suddenly switching the heat pump device from the refrigeration mode to the heating mode. Therefore, the unit may be in an unstable and unbalanced state in a short period of time. Therefore, after adjusting the opening degree of the expansion valve, maintaining the current opening degree of the expansion valve for a preset time period, and waiting for the heat pump unit to return to a stable state before exiting the defrosting mode is beneficial to improving the operation stability of the heat pump device.

[0040] In any of the above technical solutions, the value range of a is: greater than or equal to 0.0002 and less than or equal to 0.0004.

[0041] In this technical solution, the value range of the first parameter a in the coefficient formula is: 0.0002 ≤ a ≤ 0.0004. By reasonably setting the first parameter a, the accuracy of the coefficient K1 can be improved, thereby improving the reliability of adjusting the expansion valve when exiting the defrosting mode. Therefore, it can effectively ensure that the pressure difference of the refrigerant system is appropriate when exiting the defrosting mode. On the one hand, it can avoid problems such as insufficient liquid supply and low suction pressure, and on the other hand, it can avoid problems of excessive liquid supply, and can effectively improve the operation efficiency and operation reliability of the heat pump device.

[0042] In any of the above technical solutions, the value range of b is: greater than or equal to 0.0517 and less than or equal to 0.0687.

[0043] In this technical solution, the value range of the second parameter b in the coefficient formula is: 0.0517 ≤ b ≤ 0.0687. By reasonably setting the second parameter b, the accuracy of the coefficient K1 can be improved, thereby improving the reliability of adjusting the expansion valve when exiting the defrosting mode. Therefore, it can effectively ensure that the pressure difference of the refrigerant system is appropriate when exiting the defrosting mode. On the one hand, it can avoid problems such as insufficient liquid supply and low suction pressure, and on the other hand, it can avoid problems of excessive liquid supply, and can effectively improve the operation efficiency and operation reliability of the heat pump device.

[0044] In any of the above technical solutions, the value range of c is: greater than or equal to 2.3753 and less than or equal to 2.5773.

[0045] In this technical solution, the value range of the third parameter c in the coefficient formula is: 2.3753 ≤ c ≤ 2.5773. By reasonably setting the third parameter c, the accuracy of the coefficient K1 can be improved, thereby improving the reliability of the expansion valve adjustment when exiting the defrosting mode. Therefore, it can effectively ensure that the pressure difference of the refrigerant system is appropriate when exiting the defrosting mode. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operating efficiency and reliability of the heat pump device.

[0046] The second aspect of the present invention proposes a control device for a heat pump device. The heat pump device includes an expansion valve. The control device includes: an acquisition module, configured to acquire the outlet water temperature of the heat pump device and the first opening degree of the expansion valve in response to a defrosting end signal in the defrosting mode; a determination module, configured to determine a corresponding coefficient according to the outlet water temperature; determine a second opening degree according to the first opening degree and the coefficient; an adjustment module, configured to control the expansion valve to adjust the opening degree according to the second opening degree.

[0047] In this technical solution, the heat pump device may specifically be an air source heat pump unit, and the heat pump device includes a throttling component, such as an expansion valve. When the heat pump device operates in the heating mode, the temperature of the outdoor heat exchanger is relatively low. At this time, the outdoor heat exchanger may frost, and the frosting will cause a serious decline in the heat exchange efficiency of the outdoor heat exchanger. Therefore, defrosting is required.

[0048] In the defrosting mode, the four-way valve of the heat pump device changes direction, which is equivalent to controlling the heat pump device to switch from the heating mode to the cooling mode within a short time, and melts the frost condensed on the outdoor heat exchanger by raising the temperature of the outdoor heat exchanger, thereby realizing defrosting.

[0049] When the heat pump device is in the defrosting mode, if a defrosting end signal is received, that is, the heat pump device is about to exit the defrosting mode and resume normal heating mode operation, the control device of the heat pump device collects the current outlet water temperature of the heat pump device at this time, and obtains the first opening degree corresponding to the expansion valve. Among them, the first opening degree is specifically the opening degree of the heat pump device before entering the defrosting mode.

[0050] According to the current outlet water temperature, a corresponding coefficient is determined. The coefficient is used to adjust the first opening degree, that is, to adjust the opening degree of the expansion valve before entering the defrosting mode, so as to obtain a second opening degree, and adjust the opening degree of the expansion valve based on the second opening degree, thereby exiting the defrosting mode.

[0051] Specifically, the above coefficients are related to the outlet water temperature, and the outlet water temperature is related to the discharge pressure of the compressor in the heat pump device. Among them, if the outlet water temperature is low, it can be determined that the discharge pressure is low, so the pressure difference of the refrigerant system will also be relatively low. At this time, if the opening of the expansion valve is insufficient, it may cause insufficient liquid supply and too low suction pressure. If the outlet water temperature is high, it can be determined that the discharge pressure is high, and the pressure difference of the refrigerant system will also be relatively high. At this time, if the opening of the expansion valve is too high, it may cause excessive liquid supply and liquid-carrying phenomenon.

[0052] Therefore, by determining the corresponding coefficient based on the real-time outlet water temperature, determining the second opening degree matching the outlet water temperature according to the coefficient and the first opening degree, and adjusting the opening degree of the expansion valve when exiting the defrosting mode based on the second opening degree, it can ensure that the pressure difference of the refrigerant system is appropriate. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operation efficiency and operation reliability of the heat pump device.

[0053] The third aspect of the present invention proposes a control device for a heat pump device, including: a memory for storing programs or instructions; a processor for implementing the steps of the control method of the heat pump device provided in any of the above technical solutions when executing the programs or instructions. Therefore, the control device of the heat pump device also includes all the beneficial effects of the control method of the heat pump device provided in any of the above technical solutions. To avoid repetition, it will not be elaborated here.

[0054] The fourth aspect of the present invention proposes a readable storage medium, on which programs or instructions are stored, and when the programs or instructions are executed by a processor, the steps of the control method of the heat pump device provided in any of the above technical solutions are implemented. Therefore, the readable storage medium also includes all the beneficial effects of the control method of the heat pump device provided in any of the above technical solutions. To avoid repetition, it will not be elaborated here.

[0055] The fifth aspect of the present invention proposes a heat pump device, including the control device of the heat pump device provided in any of the above technical solutions; and / or the readable storage medium provided in any of the above technical solutions. Therefore, the heat pump device also includes all the beneficial effects of the control device of the heat pump device provided in any of the above technical solutions and / or the readable storage medium provided in any of the above technical solutions. To avoid repetition, it will not be elaborated here.

[0056] In the above technical solution, the heat pump device further includes: a refrigerant circuit; an expansion valve provided on the refrigerant circuit; a four-way valve provided on the refrigerant circuit.

[0057] In this technical solution, the heat pump device includes a refrigerant circuit, an expansion valve, and a four-way valve. Among them, the refrigerant circuit is connected to an indoor heat exchanger, a compressor, and an outdoor heat exchanger, and both the expansion valve and the four-way valve are arranged on the refrigerant circuit. When entering the defrosting mode, record the first opening degree of the expansion valve at this time and control the four-way valve to reverse. When exiting the defrosting mode, collect the outlet water temperature of the compressor, calculate a coefficient based on the outlet water temperature, determine a second opening degree based on the coefficient and the first opening degree, and adjust the opening degree of the expansion valve when exiting the defrosting mode according to the second opening degree, which can ensure an appropriate pressure difference in the refrigerant system. On the one hand, it can avoid problems such as insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operation efficiency and operation reliability of the heat pump device. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0059] Figure 1 The flowchart of the control method of the heat pump device according to an embodiment of the present invention is shown;

[0060] Figure 2 The structural block diagram of the control device of the heat pump device according to an embodiment of the present invention is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0061] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0062] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention may be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0063] The following refers to Figure 1 and Figure 2 to describe the control method and device, readable storage medium, and heat pump device of the heat pump device according to some embodiments of the present invention.

[0064] Embodiment 1

[0065] In some embodiments of the present invention, a control method of a heat pump device is provided. The heat pump device includes an expansion valve. Figure 1 The flowchart of the control method of the heat pump device according to an embodiment of the present invention is shown, as Figure 1 shown, the method includes:

[0066] Step 102: When in the defrosting mode, obtain the defrosting end signal;

[0067] Step 104: According to the defrosting end signal, collect the outlet water temperature of the heat pump device and determine the first opening degree of the expansion valve;

[0068] Step 106: Determine the corresponding coefficient according to the outlet water temperature;

[0069] Step 108: Determine the second opening degree according to the first opening degree and the coefficient;

[0070] Step 110: Control the expansion valve to adjust the opening degree according to the second opening degree.

[0071] In the embodiment of the present invention, the heat pump device may specifically be an air source heat pump unit, and the heat pump device includes a throttling component, such as an expansion valve. When the heat pump device operates in the heating mode, the temperature of the outdoor heat exchanger is relatively low, and at this time, the outdoor heat exchanger may frost. Frosting will cause a serious decline in the heat exchange efficiency of the outdoor heat exchanger, so defrosting is required.

[0072] In the defrosting mode, the four-way valve of the heat pump device changes direction, which is equivalent to controlling the heat pump device to switch from the heating mode to the cooling mode within a short time, and melting the frost condensed on the outdoor heat exchanger by raising the temperature of the outdoor heat exchanger, so as to achieve defrosting.

[0073] When the heat pump device is in the defrosting mode, if a defrosting end signal is received, that is, the heat pump device is about to exit the defrosting mode and resume normal heating mode operation, the control device of the heat pump device collects the current outlet water temperature of the heat pump device at this time and obtains the first opening degree corresponding to the expansion valve. Among them, the first opening degree is specifically the opening degree of the heat pump device before entering the defrosting mode.

[0074] According to the current outlet water temperature, determine the corresponding coefficient. The coefficient is used to adjust the first opening degree, that is, to adjust the opening degree of the expansion valve before entering the defrosting mode, so as to obtain the second opening degree, and adjust the opening degree of the expansion valve based on the second opening degree, so as to exit the defrosting mode.

[0075] Specifically, the above coefficient is related to the outlet water temperature, and the outlet water temperature is related to the discharge pressure of the compressor in the heat pump device. Among them, if the outlet water temperature is relatively low, it can be determined that the discharge pressure is relatively low, so the pressure difference of the refrigerant system will also be relatively low. At this time, if the opening degree of the expansion valve is insufficient, it may lead to insufficient liquid supply and too low suction pressure. If the outlet water temperature is relatively high, it can be determined that the discharge pressure is relatively high, and the pressure difference of the refrigerant system will also be relatively high. At this time, if the opening degree of the expansion valve is too high, it may lead to excessive liquid supply and liquid-carrying phenomenon.

[0076] Therefore, by determining the corresponding coefficient based on the real-time outlet water temperature, determining the second opening degree that matches the outlet water temperature according to the coefficient and the first opening degree, and adjusting the opening degree of the expansion valve when exiting the defrosting mode based on the second opening degree, it is possible to ensure that the pressure difference of the refrigerant system is appropriate. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, effectively improving the operation efficiency and reliability of the heat pump equipment.

[0077] In some embodiments of the present invention, determining the corresponding coefficient according to the outlet water temperature includes: obtaining preset parameters; calculating the coefficient through a coefficient formula, the parameters, and the outlet water temperature.

[0078] In the embodiments of the present invention, when determining the coefficient corresponding to the outlet water temperature, the real-time outlet water temperature of the heat pump equipment and the preset parameters can be substituted into the coefficient formula through the preset parameters and the preset coefficient formula, so as to calculate the corresponding coefficient through the coefficient formula. Based on the obtained coefficient and the first opening degree of the expansion valve before the defrosting mode, the second opening degree that matches the outlet water temperature is determined, and the opening degree of the expansion valve when exiting the defrosting mode is adjusted based on the second opening degree, which can ensure that the pressure difference of the refrigerant system is appropriate, prevent the problems of too low suction pressure or excessive liquid supply from occurring, ensure the operation reliability of the heat pump equipment, and ensure the stability of the defrosting mode.

[0079] In some embodiments of the present invention, the coefficient formula includes:

[0080] K1 = a × lwt 2 –b × lwt + c

[0081] Wherein, K1 is the coefficient, lwt is the outlet water temperature, and a, b, and c are parameters.

[0082] In the embodiments of the present invention, the preset parameters specifically include the first parameter a, the second parameter b, and the third parameter c. Among them, the first parameter a, the second parameter b, and the third parameter c are all fitting coefficients, and the first parameter a, the second parameter b, and the third parameter c are constants.

[0083] When calculating the coefficient that matches the outlet water temperature, calculate the square value of the outlet water temperature, calculate the first product of the first parameter a and this square value, further calculate the second product of the second parameter b and the outlet water temperature, calculate the difference between the first product and the second product, and then add the third parameter c. The final sum obtained is the above coefficient K1.

[0084] According to the coefficient formula, the coefficient K1 is only related to the outlet water temperature lwt. Based on the outlet water temperature lwt, the corresponding coefficient K1 is determined. According to the coefficient K1 and the first opening degree, the second opening degree is further determined. By controlling the expansion valve to adjust the opening degree when exiting the defrosting mode through the second opening degree, it is possible to avoid too low suction pressure or too much liquid supply, and ensure the stable operation of the heat pump device.

[0085] In some embodiments of the present invention, determining the second opening degree according to the first opening degree and the coefficient includes: calculating the product of the first opening degree and the coefficient, and determining it as the second opening degree.

[0086] In the embodiments of the present invention, the second opening degree Openness2 is determined by multiplying the first opening degree Openness1 and the coefficient K1.

[0087] Specifically, it is calculated by the following formula:

[0088] Openness2 = Openness1 × K1

[0089] Wherein, since the coefficient K1 is related to the outlet water temperature lwt, based on the outlet water temperature lwt, the corresponding coefficient K1 is determined. According to the coefficient K1 and the first opening degree Openness1, the second opening degree Openness2 is further determined. By controlling the expansion valve to adjust the opening degree to exit the defrosting mode through the second opening degree Openness2, it is possible to prevent the problems of too low suction pressure or too much liquid supply from occurring, and improve the operation reliability of the heat pump device.

[0090] In some embodiments of the present invention, controlling the expansion valve to adjust the opening degree according to the second opening degree includes: obtaining the minimum opening degree of the expansion valve; controlling the opening degree of the expansion valve to be adjusted to the larger value of the second opening degree and the minimum opening degree.

[0091] In the embodiments of the present invention, the above-mentioned minimum opening degree is specifically the lower limit of the opening degree that the expansion valve is allowed to adjust on the premise of ensuring the suction pressure and liquid supply required when exiting the defrosting mode under the condition that the opening degree of the expansion valve is too small before entering the defrosting mode. Therefore, when controlling the expansion valve to adjust the opening degree in the stage of exiting the defrosting, in order to ensure the stable operation of the heat pump system, the real-time opening degree of the adjusted expansion valve should not be less than the minimum opening degree.

[0092] Therefore, when adjusting the opening degree of the expansion valve to adapt to the stage of exiting the defrosting mode, the larger opening degree of the second opening degree and the above-mentioned minimum opening degree is used as the target opening degree, and the opening degree of the expansion valve is controlled to be adjusted to the target opening degree.

[0093] Specifically, if the opening value of the second opening is greater than the opening value of the minimum opening, the expansion valve is controlled to adjust the current opening to the second opening. Conversely, if the opening value of the second opening is less than or equal to the opening value of the minimum opening, the expansion valve is controlled to adjust the current opening to the minimum opening, thereby ensuring the operation reliability of the heat pump device.

[0094] In some embodiments of the present invention, the heat pump device further includes a four-way valve. Before responding to the defrost end signal, the control method further includes: in response to the defrost start signal, recording the first opening and controlling the four-way valve to reverse.

[0095] In the embodiments of the present invention, for heat pump devices such as air source heat pump systems, when they operate in the heating mode, since the outdoor heat exchanger needs to absorb heat from the external environment, the temperature of the outdoor heat exchanger is relatively low, generally below 0°C. Therefore, if the humidity of the external environment is relatively high, it will cause the outdoor heat exchanger to frost, affecting the heating effect. At this time, it is necessary to defrost the outdoor heat exchanger.

[0096] When it is detected that the outdoor heat exchanger is frosted and defrosting is required, the control system of the heat pump device generates a defrost start signal. After receiving the defrost start signal, the heat pump device controls the four-way valve to execute a reverse operation. At this time, it is equivalent to switching the heat pump device from the heating mode to the cooling mode. When the four-way valve reverses, the temperature of the outdoor heat exchanger will rise, and the frost on the outdoor heat exchanger is melted by releasing heat to achieve defrosting.

[0097] Before controlling the four-way valve to execute a reverse operation, record the first opening of the expansion valve before entering the defrost mode, and when the heat pump device exits the defrost mode, determine the second opening for adjusting the opening of the expansion valve when exiting the defrost mode according to the first opening and the coefficient calculated based on the water outlet temperature, thereby ensuring the operation reliability and stability of the heat pump device.

[0098] In some embodiments of the present invention, after controlling the expansion valve to adjust the opening, the method further includes: controlling the four-way valve to reverse again and maintaining the opening of the expansion valve within a preset time period.

[0099] In the embodiments of the present invention, since when exiting the defrost mode, the four-way valve executes a reverse operation, which is equivalent to controlling the heat pump device to suddenly switch from the cooling mode to the heating mode, the unit may be in an unstable and unbalanced state within a short period of time. Therefore, after adjusting the opening of the expansion valve, maintaining the current opening of the expansion valve for a preset time period and then exiting the defrost mode after the heat pump unit returns to a stable state is beneficial to improving the operation stability of the heat pump device.

[0100] In some embodiments of the present invention, the value range of a is: greater than or equal to 0.0002 and less than or equal to 0.0004.

[0101] In the embodiments of the present invention, the value range of the first parameter a in the coefficient formula is: 0.0002 ≤ a ≤ 0.0004. By reasonably setting the first parameter a, the accuracy of the coefficient K1 can be improved, thereby improving the reliability of the expansion valve adjustment when exiting the defrosting mode. Therefore, it can effectively ensure that the pressure difference of the refrigerant system is appropriate when exiting the defrosting mode. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operating efficiency and operating reliability of the heat pump device.

[0102] In some embodiments of the present invention, the value range of b is: greater than or equal to 0.0517 and less than or equal to 0.0687.

[0103] In the embodiments of the present invention, the value range of the second parameter b in the coefficient formula is: 0.0517 ≤ b ≤ 0.0687. By reasonably setting the second parameter b, the accuracy of the coefficient K1 can be improved, thereby improving the reliability of the expansion valve adjustment when exiting the defrosting mode. Therefore, it can effectively ensure that the pressure difference of the refrigerant system is appropriate when exiting the defrosting mode. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operating efficiency and operating reliability of the heat pump device.

[0104] In some embodiments of the present invention, the value range of c is: greater than or equal to 2.3753 and less than or equal to 2.5773.

[0105] In the embodiments of the present invention, the value range of the third parameter c in the coefficient formula is: 2.3753 ≤ c ≤ 2.5773. By reasonably setting the third parameter c, the accuracy of the coefficient K1 can be improved, thereby improving the reliability of the expansion valve adjustment when exiting the defrosting mode. Therefore, it can effectively ensure that the pressure difference of the refrigerant system is appropriate when exiting the defrosting mode. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operating efficiency and operating reliability of the heat pump device.

[0106] Embodiment 2

[0107] In some embodiments of the present invention, a control device for a heat pump device is proposed. The heat pump device includes an expansion valve. Figure 2 The structural block diagram of the control device of the heat pump device according to the embodiment of the present invention is shown, as Figure 2 shown, the control device 200 includes:

[0108] An acquisition module 202, configured to, in a defrosting mode, in response to a defrosting end signal, acquire the outlet water temperature of the heat pump device and the first opening degree of the expansion valve; a determination module 204, configured to determine a corresponding coefficient according to the outlet water temperature; determine a second opening degree according to the first opening degree and the coefficient; an adjustment module 206, configured to control the expansion valve to adjust the opening degree according to the second opening degree.

[0109] In an embodiment of the present invention, the heat pump device may specifically be an air source heat pump unit, and the heat pump device includes a throttling assembly, such as an expansion valve. When the heat pump device operates in a heating mode, the temperature of the outdoor heat exchanger is relatively low, and at this time, the outdoor heat exchanger may frost, and the frosting will cause a serious decline in the heat exchange efficiency of the outdoor heat exchanger. Therefore, defrosting is required.

[0110] In the defrosting mode, the four-way valve of the heat pump device commutes, which is equivalent to controlling the heat pump device to switch from the heating mode to the cooling mode within a short time, and melting the frost condensed on the outdoor heat exchanger by increasing the temperature of the outdoor heat exchanger, thereby realizing defrosting.

[0111] When the heat pump device is in the defrosting mode, if a defrosting end signal is received, that is, the heat pump device is about to exit the defrosting mode and resume normal heating mode operation, the control device of the heat pump device acquires the current outlet water temperature of the heat pump device at this time, and obtains the first opening degree corresponding to the expansion valve, where the first opening degree is specifically the opening degree of the heat pump device before entering the defrosting mode.

[0112] Determine a corresponding coefficient according to the current outlet water temperature, where the coefficient is used to adjust the first opening degree, that is, adjust the opening degree of the expansion valve before entering the defrosting mode, so as to obtain a second opening degree, and adjust the opening degree of the expansion valve based on the second opening degree, thereby exiting the defrosting mode.

[0113] Specifically, the above coefficient is related to the outlet water temperature, and the outlet water temperature is related to the exhaust pressure of the compressor in the heat pump device. Among them, if the outlet water temperature is relatively low, it can be determined that the exhaust pressure is relatively low, so the pressure difference of the refrigerant system will also be relatively low. At this time, if the opening degree of the expansion valve is insufficient, it may cause insufficient liquid supply and too low suction pressure. If the outlet water temperature is relatively high, it can be determined that the exhaust pressure is relatively high, and the pressure difference of the refrigerant system will also be relatively high. At this time, if the opening degree of the expansion valve is too high, it may cause excessive liquid supply and liquid carrying phenomenon.

[0114] Therefore, by determining the corresponding coefficient based on the real-time outlet water temperature, determining the second opening degree that matches the outlet water temperature according to the coefficient and the first opening degree, and adjusting the opening degree of the expansion valve when exiting the defrosting mode based on the second opening degree, it is possible to ensure an appropriate pressure difference in the refrigerant system. On the one hand, it can avoid problems such as insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, effectively improving the operating efficiency and reliability of the heat pump device.

[0115] In some embodiments of the present invention, the acquisition module is further configured to acquire preset parameters; the control device further includes: a calculation module, configured to calculate the coefficient through a coefficient formula, parameters, and the outlet water temperature.

[0116] In the embodiments of the present invention, when determining the coefficient corresponding to the outlet water temperature, the real-time outlet water temperature of the heat pump device and the preset parameters can be substituted into the coefficient formula through the preset parameters and the preset coefficient formula, so as to calculate the corresponding coefficient through the coefficient formula. Based on the obtained coefficient and the first opening degree of the expansion valve before the defrosting mode, the second opening degree that matches the outlet water temperature is determined, and the opening degree of the expansion valve when exiting the defrosting mode is adjusted based on the second opening degree, which can ensure an appropriate pressure difference in the refrigerant system, prevent problems such as too low suction pressure or excessive liquid supply from occurring, ensure the operating reliability of the heat pump device, and ensure the stability of the defrosting mode.

[0117] In some embodiments of the present invention, the coefficient formula includes:

[0118] K1 = a × lwt 2 –b × lwt + c

[0119] Wherein, K1 is the coefficient, lwt is the outlet water temperature, and a, b, and c are parameters.

[0120] In the embodiments of the present invention, the preset parameters specifically include a first parameter a, a second parameter b, and a third parameter c. Among them, the first parameter a, the second parameter b, and the third parameter c are all fitting coefficients, and the first parameter a, the second parameter b, and the third parameter c are constants.

[0121] When calculating the coefficient that matches the outlet water temperature, calculate the square value of the outlet water temperature, calculate the first product of the first parameter a and this square value, further calculate the second product of the second parameter b and the outlet water temperature, calculate the difference between the first product minus the second product, and then add the third parameter c. The final sum obtained is the above coefficient K1.

[0122] According to the coefficient formula, the coefficient K1 is only related to the outlet water temperature lwt. Based on the outlet water temperature lwt, the corresponding coefficient K1 is determined. According to the coefficient K1 and the first opening degree, the second opening degree is further determined. By controlling the expansion valve to adjust the opening degree when exiting the defrosting mode through the second opening degree, it is possible to avoid too low suction pressure or too much liquid supply, and ensure the operation stability of the heat pump device.

[0123] In some embodiments of the present invention, the calculation module is further configured to calculate the product of the first opening degree and the coefficient, and determine it as the second opening degree.

[0124] In an embodiment of the present invention, the second opening degree Openness2 is determined by the product of the first opening degree Openness1 and the coefficient K1.

[0125] Specifically, it is calculated by the following formula:

[0126] Openness2 = Openness1 × K1

[0127] Wherein, since the coefficient K1 is related to the outlet water temperature lwt, based on the outlet water temperature lwt, the corresponding coefficient K1 is determined. According to the coefficient K1 and the first opening degree Openness1, the second opening degree Openness2 is further determined. By controlling the expansion valve to adjust the opening degree to exit the defrosting mode through the second opening degree Openness2, it is possible to prevent the problems of too low suction pressure or too much liquid supply from occurring, and improve the operation reliability of the heat pump device.

[0128] In some embodiments of the present invention, the acquisition module is further configured to acquire the minimum opening degree of the expansion valve; the adjustment module is further configured to control the opening degree of the expansion valve to be adjusted to the larger value of the second opening degree and the minimum opening degree.

[0129] In an embodiment of the present invention, the above-mentioned minimum opening degree is specifically the lower limit of the opening degree allowed for the expansion valve on the premise of ensuring the suction pressure and liquid supply required when exiting the defrosting mode under the condition that the opening degree of the expansion valve is too small before entering the defrosting mode. Therefore, when controlling the expansion valve to adjust the opening degree in the stage of exiting the defrosting, in order to ensure the stable operation of the heat pump system, the real-time opening degree of the adjusted expansion valve should not be less than the minimum opening degree.

[0130] Therefore, when adjusting the opening degree of the expansion valve to adapt to the stage of exiting the defrosting mode, the larger opening degree of the second opening degree and the above-mentioned minimum opening degree is used as the target opening degree, and the opening degree of the expansion valve is controlled to be adjusted to the target opening degree.

[0131] Specifically, if the opening value of the second opening is greater than the opening value of the minimum opening, the expansion valve is controlled to adjust the current opening to the second opening. Conversely, if the opening value of the second opening is less than or equal to the opening value of the minimum opening, the expansion valve is controlled to adjust the current opening to the minimum opening, thereby ensuring the operation reliability of the heat pump device.

[0132] In some embodiments of the present invention, the heat pump device further includes a four-way valve, and the control device further includes: a control module, configured to record the first opening in response to a defrost start signal and control the four-way valve to change direction.

[0133] In the embodiments of the present invention, for heat pump devices such as air source heat pump systems, when operating in the heating mode, since the outdoor heat exchanger needs to absorb heat from the external environment, the temperature of the outdoor heat exchanger is relatively low, generally lower than 0°C. Therefore, if the humidity of the external environment is relatively high, it will cause frosting on the outdoor heat exchanger, affecting the heating effect, and at this time, defrosting of the outdoor heat exchanger is required.

[0134] When it is detected that the outdoor heat exchanger is frosted and defrosting is required, the control system of the heat pump device generates a defrost start signal. After receiving the defrost start signal, the heat pump device controls the four-way valve to change direction. At this time, it is equivalent to switching the heat pump device from the heating mode to the cooling mode. After the four-way valve changes direction, the temperature of the outdoor heat exchanger will rise, and the frost on the outdoor heat exchanger is melted by releasing heat to achieve defrosting.

[0135] Before controlling the four-way valve to change direction, record the first opening of the expansion valve before entering the defrost mode, and when the heat pump device exits the defrost mode, determine the second opening for adjusting the opening of the expansion valve when exiting the defrost mode according to the first opening and the coefficient calculated based on the outlet water temperature, thereby ensuring the operation reliability and stability of the heat pump device.

[0136] In some embodiments of the present invention, the control module is further configured to control the four-way valve to change direction again and maintain the opening of the expansion valve within a preset duration.

[0137] In the embodiments of the present invention, since when exiting the defrost mode, the four-way valve changes direction, which is equivalent to controlling the heat pump device to suddenly switch from the cooling mode to the heating mode, the unit may be in an unstable and unbalanced state within a short period of time. Therefore, after adjusting the opening of the expansion valve, maintaining the expansion valve at the current opening for a preset duration, and then exiting the defrost mode after the heat pump unit returns to a stable state is beneficial to improving the operation stability of the heat pump device.

[0138] In some embodiments of the present invention, the value range of a is: greater than or equal to 0.0002 and less than or equal to 0.0004.

[0139] In the embodiments of the present invention, the value range of the first parameter a in the coefficient formula is: 0.0002 ≤ a ≤ 0.0004. By reasonably setting the first parameter a, the accuracy of the coefficient K1 can be improved, thereby improving the reliability of the expansion valve adjustment when exiting the defrosting mode. Therefore, it can effectively ensure that the pressure difference of the refrigerant system is appropriate when exiting the defrosting mode. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operation efficiency and operation reliability of the heat pump device.

[0140] In some embodiments of the present invention, the value range of b is: greater than or equal to 0.0517 and less than or equal to 0.0687.

[0141] In the embodiments of the present invention, the value range of the second parameter b in the coefficient formula is: 0.0517 ≤ b ≤ 0.0687. By reasonably setting the second parameter b, the accuracy of the coefficient K1 can be improved, thereby improving the reliability of the expansion valve adjustment when exiting the defrosting mode. Therefore, it can effectively ensure that the pressure difference of the refrigerant system is appropriate when exiting the defrosting mode. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operation efficiency and operation reliability of the heat pump device.

[0142] In some embodiments of the present invention, the value range of c is: greater than or equal to 2.3753 and less than or equal to 2.5773.

[0143] In the embodiments of the present invention, the value range of the third parameter c in the coefficient formula is: 2.3753 ≤ c ≤ 2.5773. By reasonably setting the third parameter c, the accuracy of the coefficient K1 can be improved, thereby improving the reliability of the expansion valve adjustment when exiting the defrosting mode. Therefore, it can effectively ensure that the pressure difference of the refrigerant system is appropriate when exiting the defrosting mode. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operation efficiency and operation reliability of the heat pump device.

[0144] Embodiment Three

[0145] In some embodiments of the present invention, a control device for a heat pump device is provided, including: a memory for storing programs or instructions; a processor for implementing the steps of the control method of the heat pump device provided in any of the above embodiments when executing the programs or instructions. Therefore, the control device of the heat pump device also includes all the beneficial effects of the control method of the heat pump device provided in any of the above embodiments. To avoid repetition, it will not be elaborated here.

[0146] Embodiment Four

[0147] In some embodiments of the present invention, a readable storage medium is provided, on which a program or instructions are stored. When the program or instructions are executed by a processor, the steps of the control method of the heat pump device provided in any of the above embodiments are implemented. Therefore, this readable storage medium also includes all the beneficial effects of the control method of the heat pump device provided in any of the above embodiments. To avoid repetition, they will not be elaborated herein.

[0148] Embodiment Five

[0149] In some embodiments of the present invention, a heat pump device is provided, including the control device of the heat pump device provided in any of the above embodiments; and / or the readable storage medium provided in any of the above embodiments. Therefore, this heat pump device also includes all the beneficial effects of the control device of the heat pump device and / or the readable storage medium provided in any of the above embodiments. To avoid repetition, they will not be elaborated herein.

[0150] In some embodiments of the present invention, the heat pump device further includes: a refrigerant circuit; an expansion valve provided on the refrigerant circuit; a four-way valve provided on the refrigerant circuit.

[0151] In the embodiments of the present invention, the heat pump device includes a refrigerant circuit, an expansion valve and a four-way valve. Among them, the refrigerant circuit communicates with an indoor heat exchanger, a compressor and an outdoor heat exchanger, and both the expansion valve and the four-way valve are arranged on the refrigerant circuit. When entering the defrosting mode, record the first opening degree of the expansion valve at this time, and control the four-way valve to change its direction. When exiting the defrosting mode, collect the outlet water temperature of the compressor, calculate a coefficient based on the outlet water temperature, determine a second opening degree based on the coefficient and the first opening degree, and adjust the opening degree of the expansion valve when exiting the defrosting mode according to the second opening degree, which can ensure that the pressure difference of the refrigerant system is appropriate. On the one hand, it can avoid the problems of insufficient liquid supply and low suction pressure, and on the other hand, it can avoid the problem of excessive liquid supply, and can effectively improve the operation efficiency and operation reliability of the heat pump device.

[0152] In the description of the present invention, the term "plurality" refers to two or more, unless otherwise clearly defined. The orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention; the terms "connection", "installation", "fixation", etc. should all be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0153] In the description of the present invention, the descriptions of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In the present invention, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0154] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A control method for a heat pump device, characterized in that, The heat pump device includes an expansion valve, and the method includes: In the defrosting mode, in response to a defrosting end signal, obtain the water outlet temperature of the heat pump device and the first opening degree of the expansion valve; Determine a corresponding coefficient according to the water outlet temperature; Determine a second opening degree according to the first opening degree and the coefficient; Control the expansion valve to adjust the opening degree according to the second opening degree; The determining a corresponding coefficient according to the water outlet temperature includes: Obtain preset parameters; Calculate the coefficient through a coefficient formula, the parameters, and the water outlet temperature; The coefficient formula includes: K1 = a × lwt 2 – b × lwt + c wherein, K1 is the coefficient, lwt is the outlet water temperature, a , b and c are the parameters; The determining a second opening degree according to the first opening degree and the coefficient includes: Calculate the product of the first opening degree and the coefficient, and determine it as the second opening degree; The controlling the expansion valve to adjust the opening degree according to the second opening degree includes: Obtain the minimum opening degree of the expansion valve; Control the opening degree of the expansion valve to be adjusted to the larger value of the second opening degree and the minimum opening degree; a The value range is: greater than or equal to 0.0002 and less than or equal to 0.0004; b The value range is: greater than or equal to 0.0517 and less than or equal to 0.0687; c The value range is: greater than or equal to 2.3753 and less than or equal to 2.5773; The first opening degree is the opening degree of the heat pump device before entering the defrosting mode; The minimum opening degree is the lower limit of the opening degree that the expansion valve is allowed to adjust on the premise of ensuring the suction pressure and liquid supply required when exiting the defrosting mode when the opening degree of the expansion valve is too small before entering the defrosting mode.

2. The control method according to claim 1, characterized in that The heat pump device further includes a four-way valve. Before the response to the defrosting end signal, the control method further includes: In response to a defrosting start signal, record the first opening degree and control the four-way valve to change direction.

3. The control method according to claim 2, characterized in that, After the controlling the expansion valve to adjust the opening degree, the method further includes: Control the four-way valve to change direction again and maintain the opening degree of the expansion valve within a preset time period.

4. A control device for a heat pump device, characterized in that, The heat pump device includes an expansion valve, and the control device includes: An acquisition module, configured to obtain the water outlet temperature of the heat pump device and the first opening degree of the expansion valve in the defrosting mode in response to a defrosting end signal; A determination module, configured to determine a corresponding coefficient according to the water outlet temperature; determine a second opening degree according to the first opening degree and the coefficient; An adjustment module, configured to control the expansion valve to adjust the opening degree according to the second opening degree; The acquisition module is further configured to obtain preset parameters; the control device further includes: a calculation module, configured to calculate the coefficient through a coefficient formula, parameters, and the water outlet temperature; the coefficient formula includes: K1 = a × lwt 2 – b × lwt + c Among them, K1 is a coefficient, lwt is the outlet water temperature, and a, b, and c are parameters; the calculation module is further configured to calculate the product of the first opening degree and the coefficient, and determine it as the second opening degree; the acquisition module is further configured to acquire the minimum opening degree of the expansion valve; the adjustment module is further configured to control the opening degree of the expansion valve to be adjusted to the larger value of the second opening degree and the minimum opening degree; the value range of a is: greater than or equal to 0.0002 and less than or equal to 0.0004; the value range of b is: greater than or equal to 0.0517 and less than or equal to 0.0687; the value range of c is: greater than or equal to 2.3753 and less than or equal to 2.5773; the first opening degree is the opening degree of the heat pump device before entering the defrosting mode; the minimum opening degree is the lower limit of the opening degree allowed for the expansion valve on the premise of ensuring the suction pressure and liquid supply required when exiting the defrosting mode in the case where the opening degree of the expansion valve is too small before entering the defrosting mode.

5. A control device for a heat pump device, characterized in that, Comprising: A memory for storing programs or instructions; A processor for implementing the control method according to any one of claims 1 to 3 when executing the program or instructions.

6. A readable storage medium having a program or instructions stored thereon, characterized in that, The program or instructions, when executed by the processor, implement the control method according to any one of claims 1 to 3.

7. A heat pump device, characterized in that, Comprising: The control device according to claim 4 or 5; And / or The readable storage medium according to claim 6.

8. The heat pump device according to claim 7, characterized in that, Further comprising: A refrigerant circuit; An expansion valve provided on the refrigerant circuit; A four-way valve provided on the refrigerant circuit.

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