Control Method, Control Device, Heat Pump System and Storage Medium of Heat Pump System

Abstract

The present invention provides a control method, a control device, a heat pump system and a storage medium for a heat pump system. The control method includes: obtaining the current opening degree of the electronic expansion valve; obtaining the upper water temperature, the lower water temperature of the water tank and the exhaust gas temperature of the compressor, and obtaining the exhaust gas superheat degree according to the upper water temperature, the lower water temperature and the exhaust gas temperature; correcting the current opening degree according to the upper water temperature, the lower water temperature and the exhaust gas superheat degree; According to the technical solution of the embodiment of the present invention, not only can the reliable operation of the heat pump system be ensured, but also the uniformity of the water temperature inside the water tank can be effectively improved, thereby improving the hot water output rate of the heat pump system and better meeting the actual hot water usage needs of users.

Description

Technical Field

[0001] The present invention relates to the field of heat pump systems, and particularly to a control method, a control device, a heat pump system and a storage medium for a heat pump system. Background Art

[0002] Currently, an air source heat pump system usually uses an electronic expansion valve to adjust the refrigerant flow rate in the refrigerant circulation loop. In related technologies, the electronic expansion valve is generally controlled by the suction superheat. For the case where the heat pump system is equipped with a water tank, during the static water heating process, as the water temperature inside the water tank continuously rises, the heating load continuously changes, and the output of the heat pump system changes dynamically. Since the refrigerant flow direction in the condensation heat exchange process of the water tank is generally from top to bottom, the water temperature at the upper part of the water tank usually condenses and exchanges heat first, which will cause uneven heating of the hot water inside the water tank. As a result, the water temperature at the upper part reaches the set temperature and the system shuts down, while the water temperature at the lower part has not been heated to the required temperature, thus reducing the hot water output rate of the heat pump system. If a single suction superheat control method is adopted, the problem of uneven water temperature inside the water tank cannot be effectively solved, it is difficult to meet the actual hot water usage requirements of users, and the user experience is reduced. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. For this purpose, the present invention provides a control method, a control device, a heat pump system and a storage medium for a heat pump system, which can not only ensure the reliable operation of the heat pump system, but also effectively improve the uniformity of the water temperature inside the water tank, thereby increasing the hot water output rate of the heat pump system and better meeting the actual hot water usage requirements of users.

[0004] In a first aspect, an embodiment of the present invention provides a control method for a heat pump system. The heat pump system includes a compressor, a water tank and an electronic expansion valve. The water tank is provided with a heat exchange coil. The exhaust port of the compressor is connected to the inlet of the heat exchange coil, and the outlet of the heat exchange coil is connected to the suction port of the compressor through the electronic expansion valve. The control method includes:

[0005] Obtain the current opening degree of the electronic expansion valve;

[0006] Obtain the upper water temperature, the lower water temperature of the water tank and the exhaust temperature of the compressor, and obtain the exhaust superheat according to the upper water temperature, the lower water temperature and the exhaust temperature;

[0007] Correct the current opening degree according to the upper water temperature, the lower water temperature and the exhaust superheat.

[0008] The control method of the heat pump system provided by the embodiment of the present invention has at least the following beneficial effects: By obtaining the superheat degree of exhaust based on the upper water temperature, lower water temperature inside the water tank and the exhaust temperature of the compressor, the superheat degree of exhaust can reflect both the working reliability of the heat pump system and fully consider the hot water heating situation inside the water tank. And the current opening degree of the electronic expansion valve is corrected according to the upper water temperature, lower water temperature and superheat degree of exhaust. Since the upper water temperature, lower water temperature and superheat degree of exhaust are added to correct and adjust the current opening degree, comprehensively considering the water temperature stratification situation inside the water tank and the influence of the superheat degree of exhaust on the reliability of the heat pump system, it can not only ensure the reliable operation of the heat pump system, but also effectively improve the uniformity of the water temperature inside the water tank, thereby improving the hot water output rate of the heat pump system, being able to better meet the actual hot water usage needs of users, and being beneficial to improving the user experience.

[0009] In the above control method of the heat pump system, the correcting the current opening degree according to the upper water temperature, the lower water temperature and the superheat degree of exhaust includes:

[0010] Calculating the water temperature difference between the upper water temperature and the lower water temperature;

[0011] Correcting the current opening degree according to the water temperature difference and the superheat degree of exhaust.

[0012] In this embodiment, by calculating the water temperature difference between the upper water temperature and the lower water temperature, the temperature difference situation of the hot water inside the water tank can be determined, and the current opening degree is corrected according to the water temperature difference and the superheat degree of exhaust. Through the superheat degree of exhaust, the working reliability situation of the heat pump system can be determined, and through the water temperature difference, the actual heating situation of the hot water inside the water tank can be determined. Combining the water temperature difference and the superheat degree of exhaust can better perform coupled control on the current opening degree of the electronic expansion valve, so that the current opening degree of the electronic expansion valve can fall within a suitable opening range, thereby better improving the uneven hot water heating situation inside the water tank, being beneficial to improving the hot water output rate of the heat pump system, and facilitating better meeting the actual hot water usage needs of users.

[0013] In the above control method of the heat pump system, the correcting the current opening degree according to the water temperature difference and the superheat degree of exhaust includes:

[0014] When the water temperature difference is greater than a first preset value and the superheat degree of exhaust is greater than a second preset value, increasing the current opening degree;

[0015] When the water temperature difference is greater than a first preset value, and the superheat degree of exhaust is greater than a third preset value and less than or equal to the second preset value, maintaining the current opening degree;

[0016] When the water temperature difference is greater than a first preset value and the superheat degree of exhaust is less than or equal to the third preset value, decreasing the current opening degree;

[0017] Wherein, the second preset value is greater than the third preset value.

[0018] In this embodiment, when it is detected that the water temperature difference is greater than the first preset value, it means that the water temperature difference between the upper and lower water temperatures in the water tank is too large. In this case, when the exhaust superheat is greater than the second preset value, it is considered that the current exhaust superheat is too large, and the current opening of the electronic expansion valve can be increased, which can increase the refrigerant flow rate in the refrigerant circulation loop, thereby effectively improving the heat exchange of the water at the lower part of the water tank, and then reducing the water temperature difference inside the water tank and effectively improving the hot water output rate of the heat pump system; when the exhaust superheat is greater than the third preset value and less than or equal to the second preset value, it is considered that the current exhaust superheat is within a suitable range and meets the reliability requirements of the heat pump system, and the current opening can be maintained, that is, there is no need to adjust the current opening of the electronic expansion valve; when the exhaust superheat is less than or equal to the third preset value, it is considered that the current exhaust superheat is too small. If the exhaust superheat is insufficient, there is a risk of liquid return, which affects the reliability of the compressor operation. Then, the current opening of the electronic expansion valve can be reduced, thereby increasing the exhaust superheat and ensuring the stable and reliable operation of the heat pump system.

[0019] In the control method of the above heat pump system, when the water temperature difference is greater than the first preset value and the exhaust superheat is greater than the second preset value, the increasing of the current opening includes:

[0020] Adding a preset first opening adjustment value on the basis of the current opening;

[0021] Or, multiplying the current opening by a preset first opening adjustment coefficient to increase the current opening, and the first opening adjustment coefficient is greater than 1.

[0022] In this embodiment, when the water temperature difference is greater than the first preset value and the exhaust superheat is greater than the second preset value, it means that the water temperature difference inside the water tank is too large and the exhaust superheat is too large. Then, a preset first opening adjustment value can be added on the basis of the current opening to increase the current opening of the electronic expansion valve, or the current opening can be multiplied by a preset first opening adjustment coefficient to increase the current opening of the electronic expansion valve. By increasing the current opening, the water temperature difference inside the water tank can be reduced, and the hot water output rate of the heat pump system can be effectively improved.

[0023] In the control method of the above heat pump system, when the water temperature difference is greater than the first preset value and the exhaust superheat is less than or equal to the third preset value, the decreasing of the current opening includes:

[0024] Subtracting a preset second opening adjustment value from the current opening;

[0025] Alternatively, multiply the current opening degree by a preset second opening degree adjustment coefficient to reduce the current opening degree, where the second opening degree adjustment coefficient is greater than 0 and less than 1.

[0026] In this embodiment, when the water temperature difference is greater than a first preset value and the exhaust superheat degree is less than or equal to a third preset value, it indicates that the water temperature difference inside the water tank is too large and the exhaust superheat degree is insufficient. Then, a preset second opening degree adjustment value can be subtracted from the current opening degree to reduce the current opening degree of the electronic expansion valve, or the current opening degree can be multiplied by a preset second opening degree adjustment coefficient to reduce the current opening degree of the electronic expansion valve. By reducing the current opening degree, the exhaust superheat degree can be increased to ensure the stable and reliable operation of the heat pump system.

[0027] In the control method of the above heat pump system, the step of correcting the current opening degree according to the water temperature difference and the exhaust superheat degree further includes:

[0028] When the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is greater than the third preset value, maintain the current opening degree;

[0029] When the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is less than or equal to the third preset value, reduce the current opening degree.

[0030] In this embodiment, when it is detected that the water temperature difference is less than or equal to the first preset value, it indicates that the water temperature difference is within a reasonable range. In this case, when the exhaust superheat degree is greater than the third preset value, it is considered that the exhaust superheat degree is still within the range allowed by the heat pump system. Although the exhaust superheat degree is slightly large at this time, it does not affect the working reliability of the heat pump system. At the same time, since the water temperature difference is already within a reasonable range, there is no need to further adjust the water temperature inside the water tank, so the current opening degree is maintained, that is, there is no need to adjust the current opening degree of the electronic expansion valve; when the exhaust superheat degree is less than or equal to the third preset value, it is considered that the current exhaust superheat degree is too small. If the exhaust superheat degree is insufficient, it will affect the running reliability of the compressor. Then, the current opening degree of the electronic expansion valve can be reduced, so that the exhaust superheat degree can be increased to ensure the stable and reliable operation of the heat pump system.

[0031] In the control method of the above heat pump system, when the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is less than or equal to the third preset value, the step of reducing the current opening degree includes:

[0032] Subtract a preset third opening degree adjustment value from the current opening degree;

[0033] Alternatively, multiply the current opening degree by a preset third opening degree adjustment coefficient to reduce the current opening degree, where the third opening degree adjustment coefficient is greater than 0 and less than 1.

[0034] In this embodiment, when the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is less than or equal to the third preset value, it means that the water temperature difference is within a reasonable range and the exhaust superheat degree is insufficient. Then, the current opening of the electronic expansion valve can be reduced by subtracting the preset third opening adjustment value from the current opening, or the current opening can be multiplied by the preset third opening adjustment coefficient to reduce the current opening of the electronic expansion valve. By reducing the current opening, the exhaust superheat degree can be increased to ensure the stable and reliable operation of the heat pump system.

[0035] In the control method of the above heat pump system, the obtaining of the exhaust superheat degree according to the upper water temperature, the lower water temperature and the exhaust temperature includes:

[0036] Calculating the average water temperature of the upper water temperature and the lower water temperature;

[0037] Subtracting the average water temperature from the exhaust temperature to obtain the exhaust superheat degree.

[0038] In this embodiment, the average water temperature of the upper water temperature and the lower water temperature is calculated. By using the average water temperature, it can be closer to the saturation temperature corresponding to the compressor. Then, subtracting the average water temperature from the exhaust temperature can obtain the exhaust superheat degree. There is no need to additionally set a pressure sensor, which can effectively save costs. In addition, since the exhaust superheat degree is obtained in this way, it can better reflect the hot water heating situation inside the water tank, so as to better meet the hot water use needs of users.

[0039] In the control method of the above heat pump system, before obtaining the current opening of the electronic expansion valve, the control method further includes:

[0040] Obtaining the suction superheat degree and controlling the current opening of the electronic expansion valve according to the suction superheat degree so that the suction superheat degree falls within a preset range; wherein, the suction superheat degree is obtained by subtracting the evaporation temperature of the evaporator from the suction temperature of the compressor.

[0041] In this embodiment, first, the current opening of the electronic expansion valve is controlled according to the suction superheat degree, so that the suction superheat degree falls within a preset range. By preferentially adjusting the current opening of the electronic expansion valve by using the suction superheat degree, the opening adjustment efficiency can be improved, so that the current opening of the electronic expansion valve can quickly reach the opening range corresponding to meeting the normal operation requirements of the heat pump system. Then, the current opening is corrected according to the upper water temperature, the lower water temperature and the exhaust superheat degree, which can solve the problem of uneven hot water heating inside the water tank. In addition, by using the method of subtracting the evaporation temperature of the evaporator from the suction temperature of the compressor to obtain the suction superheat degree, the cost can be greatly reduced.

[0042] In the control method of the above heat pump system, the controlling the current opening of the electronic expansion valve according to the suction superheat degree includes:

[0043] When the suction superheat degree is greater than the upper limit value of the preset range, increase the current opening degree of the electronic expansion valve;

[0044] When the suction superheat degree is less than the lower limit value of the preset range, decrease the current opening degree of the electronic expansion valve.

[0045] In this embodiment, when the suction superheat degree is greater than the upper limit value of the preset range, it indicates that the current suction superheat degree is too large. Then, increasing the current opening degree of the electronic expansion valve can increase the refrigerant flow rate in the refrigerant circulation loop, thereby appropriately reducing the suction superheat degree and ensuring that the suction superheat degree can fall within the preset range; when the suction superheat degree is less than the lower limit value of the preset range, it indicates that the current suction superheat degree is too small. Then, decreasing the current opening degree of the electronic expansion valve can reduce the refrigerant flow rate in the refrigerant circulation loop, thereby appropriately increasing the suction superheat degree and ensuring that the suction superheat degree can fall within the preset range.

[0046] In a second aspect, an embodiment of the present invention provides an operation control device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. The processor executes the program to implement the control method described in the first aspect embodiment above.

[0047] According to the operation control device provided by the embodiment of the present invention, it has at least the following beneficial effects: The discharge superheat degree can be obtained based on the upper water temperature, lower water temperature inside the water tank, and the discharge temperature of the compressor, which can make the discharge superheat degree reflect both the working reliability of the heat pump system and fully consider the hot water heating situation inside the water tank. And the current opening degree of the electronic expansion valve is corrected according to the upper water temperature, lower water temperature, and discharge superheat degree. Since the upper water temperature, lower water temperature, and discharge superheat degree are added to correct and adjust the current opening degree, comprehensively considering the influence of the water temperature stratification inside the water tank and the discharge superheat degree on the reliability of the heat pump system, it can not only ensure the reliable operation of the heat pump system, but also effectively improve the uniformity of the water temperature inside the water tank, thereby improving the hot water output rate of the heat pump system, better meeting the actual hot water usage needs of users, and being beneficial to improving the user experience.

[0048] In a third aspect, an embodiment of the present invention provides a heat pump system, including the operation control device described in the second aspect embodiment above.

[0049] The heat pump system provided by the embodiment of the present invention has at least the following beneficial effects: The superheat degree of exhaust can be obtained based on the upper water temperature, lower water temperature inside the water tank, and the exhaust temperature of the compressor. This enables the superheat degree of exhaust to not only reflect the working reliability of the heat pump system but also fully consider the hot water heating situation inside the water tank. Moreover, the current opening degree of the electronic expansion valve is corrected according to the upper water temperature, lower water temperature, and superheat degree of exhaust. Since the correction adjustment of the current opening degree is increased by the upper water temperature, lower water temperature, and superheat degree of exhaust, comprehensively considering the water temperature stratification situation inside the water tank and the influence of the superheat degree of exhaust on the reliability of the heat pump system, it can not only ensure the reliable operation of the heat pump system but also effectively improve the uniformity of the water temperature inside the water tank, thereby increasing the hot water output rate of the heat pump system, better meeting the actual hot water usage needs of users, and being beneficial to improving the user experience.

[0050] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium storing computer-executable instructions for causing a computer to execute the control method described in the first aspect embodiment above.

[0051] The computer-readable storage medium provided by the embodiment of the present invention has at least the following beneficial effects: The superheat degree of exhaust can be obtained based on the upper water temperature, lower water temperature inside the water tank, and the exhaust temperature of the compressor. This enables the superheat degree of exhaust to not only reflect the working reliability of the heat pump system but also fully consider the hot water heating situation inside the water tank. Moreover, the current opening degree of the electronic expansion valve is corrected according to the upper water temperature, lower water temperature, and superheat degree of exhaust. Since the correction adjustment of the current opening degree is increased by the upper water temperature, lower water temperature, and superheat degree of exhaust, comprehensively considering the water temperature stratification situation inside the water tank and the influence of the superheat degree of exhaust on the reliability of the heat pump system, it can not only ensure the reliable operation of the heat pump system but also effectively improve the uniformity of the water temperature inside the water tank, thereby increasing the hot water output rate of the heat pump system, better meeting the actual hot water usage needs of users, and being beneficial to improving the user experience.

[0052] Other features and advantages of the present invention will be described in the subsequent description, and some will become obvious from the description or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The present invention will be further described below in conjunction with the drawings and embodiments;

[0054] Figure 1 It is a schematic structural diagram of the heat pump system provided by Embodiment 1 of the present invention.

[0055] Figure 2It is the flowchart of the control method of the heat pump system provided in the second embodiment of the present invention;

[0056] Figure 3 It is the flowchart of the control method of the heat pump system provided in the third embodiment of the present invention;

[0057] Figure 4 It is the flowchart of the control method of the heat pump system provided in the fourth embodiment of the present invention;

[0058] Figure 5 It is the flowchart of the control method of the heat pump system provided in the fifth embodiment of the present invention;

[0059] Figure 6 It is the flowchart of the control method of the heat pump system provided in the sixth embodiment of the present invention;

[0060] Figure 7 It is the flowchart of the control method of the heat pump system provided in the seventh embodiment of the present invention;

[0061] Figure 8 It is the overall flowchart of the control method of the heat pump system provided in the eighth embodiment of the present invention;

[0062] Figure 9 It is the structural schematic diagram of the operation control device provided in the ninth embodiment of the present invention. Detailed implementation manners

[0063] This part will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the drawings. The function of the drawings is to supplement the description of the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the protection scope of the present invention.

[0064] It should be understood that in the description of the embodiments of the present invention, if there is a description of "first", "second", etc., it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features. "At least one" means one or more, "a plurality" means two or more, greater than, less than, exceeding, etc. are understood as not including the number itself, above, below, within, etc. are understood as including the number itself, the meaning of "several" is one or more, unless otherwise clearly and specifically defined. "And / or" describes the association relationship of associated objects and indicates that three relationships can exist. It can be understood that A and / or B can represent the situation of A existing alone, A and B existing simultaneously, and B existing alone. Where A and B can be singular or plural.

[0065] In addition, unless otherwise clearly specified and defined, the term "connected" should be understood in a broad sense. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection or a connection capable of mutual communication; it can be directly connected or indirectly connected through an intermediate medium. It should be noted that although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from that in the flowchart.

[0066] It should be noted that the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0067] The control method, control device, heat pump system and storage medium provided by the embodiments of the present invention can not only ensure the reliable operation of the heat pump system, but also effectively improve the uniformity of the water temperature inside the water tank, thereby improving the hot water output rate of the heat pump system and better meeting the actual hot water use needs of users.

[0068] The following further elaborates on the embodiments of the present invention with reference to the accompanying drawings.

[0069] As Figure 1 shown, the heat pump system provided by the embodiments of the present invention includes a compressor 100, a water tank 200 and an electronic expansion valve 300. The water tank 200 is provided with a heat exchange coil 400, and the heat exchange coil 400 can be wound around the periphery of the water tank 200. The exhaust port a of the compressor 100 is connected to the inlet of the heat exchange coil 400, and the outlet of the heat exchange coil 400 is connected to the suction port b of the compressor 100 through the electronic expansion valve 300. The compressor 100 can discharge the high-temperature and high-pressure gaseous refrigerant from the exhaust port a and input it into the heat exchange coil 400, and the refrigerant can exchange heat with the water in the water tank 200, thereby heating the water in the water tank 200. By providing an electronic expansion valve 300 on the refrigerant circulation circuit of the heat pump system, the refrigerant flow rate in the refrigerant circulation circuit can be adjusted.

[0070] It should be noted that the heat pump system further includes a four-way valve 500 and an evaporator 600. When the heat pump system operates in heating mode, the refrigerant flow direction is as follows: the high-temperature and high-pressure gaseous refrigerant compressed by the compressor 100 is discharged from the exhaust port a, then sequentially passes through the first end c and the second end d of the four-way valve 500, and then is input into the heat exchange coil 400 through the inlet of the heat exchange coil 400. After liquefying and releasing heat through the heat exchange coil 400, it flows downward to condense and heat the water in the water tank 200, and then flows out from the outlet of the heat exchange coil 400. After throttling by the electronic expansion valve 300, it reaches the evaporator 600 for vaporization and heat absorption, and finally returns to the suction port b of the compressor 100 sequentially through the third end e and the fourth end f of the four-way valve 500.

[0071] It should be noted that the heat pump system may further include an exhaust gas temperature sensor 710 for detecting the exhaust gas temperature of the compressor 100, a suction gas temperature sensor 720 for detecting the suction gas temperature of the compressor 100, an upper temperature sensor 730 for detecting the water temperature at the upper part of the water tank 200, a lower temperature sensor 740 for detecting the water temperature at the lower part of the water tank 200, and an evaporator temperature sensor 750 for detecting the evaporation temperature of the evaporator 600.

[0072] Those skilled in the art can understand that Figure 1 the heat pump system shown in does not limit the embodiments of the present invention, and may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0073] As Figure 2 shown, an embodiment of the first aspect of the present invention provides a control method for a heat pump system, including but not limited to steps S110 to S130:

[0074] Step S110: Obtain the current opening degree of the electronic expansion valve;

[0075] It should be noted that since the refrigerant flowing through the heat exchange coil exchanges heat with the water in the water tank and the water in the water tank is always in a static state, this heating method belongs to static heating. During the static water heating process, it is often necessary to use an electronic expansion valve to adjust the refrigerant flow rate in the refrigerant circulation loop. The current opening degree can be understood as the opening degree of the electronic expansion valve in the current operating state, which can meet the normal working requirements of the heat pump system.

[0076] Step S120: Obtain the upper water temperature, lower water temperature of the water tank, and the exhaust gas temperature of the compressor, and obtain the exhaust gas superheat degree based on the upper water temperature, lower water temperature, and exhaust gas temperature;

[0077] Based on the characteristic that the flow direction of the refrigerant during the condensation heat exchange process is generally from top to bottom, there is usually a certain difference between the upper water temperature and the lower water temperature of the water tank, which will cause uneven heating of the hot water inside the water tank, that is, the problem of water temperature stratification inside the water tank. By obtaining the upper water temperature and the lower water temperature of the water tank, the problem of water temperature stratification inside the water tank can be fully considered, and the exhaust gas superheat degree is obtained based on the upper water temperature, lower water temperature, and exhaust gas temperature. This exhaust gas superheat degree can not only reflect the reliability of the heat pump system, but also effectively reflect the hot water heating situation inside the water tank, so as to better meet the hot water usage needs of users.

[0078] Step S130: Correct the current opening degree according to the upper water temperature, lower water temperature, and exhaust gas superheat degree.

[0079] It should be noted that during the operation of the heat pump system, the current opening degree of the electronic expansion valve may not meet the actual hot water usage requirements of users. By combining the upper water temperature, lower water temperature, and exhaust superheat degree to correct the current opening degree, the current opening degree of the electronic expansion valve can be coupledly controlled, which can not only ensure the reliable operation of the compressor but also effectively optimize the problem of uneven hot water heating inside the water tank.

[0080] It should be noted that specifically, correcting the current opening degree can be increasing the current opening degree, or decreasing the current opening degree, or maintaining the current opening degree. The embodiments of the present invention do not make specific limitations on this.

[0081] The control method of the heat pump system provided by the first aspect of the above embodiments can obtain the exhaust superheat degree according to the upper water temperature, lower water temperature inside the water tank, and the exhaust temperature of the compressor. This can make the exhaust superheat degree not only reflect the working reliability of the heat pump system but also fully consider the hot water heating situation inside the water tank, and correct the current opening degree of the electronic expansion valve according to the upper water temperature, lower water temperature, and exhaust superheat degree. Since the upper water temperature, lower water temperature, and exhaust superheat degree are added to correct and adjust the current opening degree, comprehensively considering the influence of the water temperature stratification inside the water tank and the exhaust superheat degree on the reliability of the heat pump system, it can not only ensure the reliable operation of the heat pump system but also effectively improve the uniformity of the water temperature inside the water tank, thereby increasing the hot water output rate of the heat pump system and being able to better meet the actual hot water usage requirements of users, which is beneficial to improving the user experience.

[0082] It should be noted that when the electronic expansion valve is working normally at the current opening degree, there may be a situation of uneven hot water heating inside the water tank, resulting in a decrease in the hot water output rate due to the water temperature stratification inside the water tank. The embodiments of the present invention realize the coupled control of the current opening degree of the electronic expansion valve by combining the upper water temperature, lower water temperature, and exhaust superheat degree. This can not only ensure that the exhaust superheat degree of the compressor meets the reliability requirements of the heat pump system but also more effectively solve the problem of water temperature stratification in the water tank, facilitating the better realization of the uniformity of the hot water distribution inside the water tank. Without increasing costs, it can increase the hot water output rate of the heat pump system, thereby greatly improving the market competitiveness of the heat pump system.

[0083] It can be understood that for the method of controlling the opening of the electronic expansion valve by using the suction superheat degree in the related technology, although the current opening of the electronic expansion valve can ensure the reliability of the heat pump system operation, it cannot reflect the hot water heating situation inside the water tank. In the process of condensation heat exchange in the water tank, the refrigerant flow direction is generally from top to bottom, so there will often be an obvious problem of water temperature stratification inside the water tank. The solution adopted in the embodiment of the present invention is different from that in the related technology. By introducing the discharge superheat degree and combining the upper water temperature and the lower water temperature to correct the current opening of the electronic expansion valve, it is possible to optimize the problem of uneven hot water heating inside the water tank on the premise of ensuring the stable reliability of the heat pump system, and reduce the situations where the water temperature changes too much and the water consumption is insufficient during the actual use of hot water by users.

[0084] As Figure 3 shown, in the above control method of the heat pump system, in step S130, correcting the current opening according to the upper water temperature, the lower water temperature and the discharge superheat degree includes, but is not limited to, step S210 and step S220:

[0085] Step S210: Calculate the water temperature difference between the upper water temperature and the lower water temperature;

[0086] Step S220: Correct the current opening according to the water temperature difference and the discharge superheat degree.

[0087] It should be noted that since the refrigerant flow direction in the water tank during the condensation heat exchange process is generally from top to bottom, the water at the upper part of the water tank usually condenses and exchanges heat preferentially, which will lead to uneven hot water heating inside the water tank. The upper water temperature is usually higher than the lower water temperature, and it is easy to have a too large water temperature difference between the upper and lower parts. As a result, the system will stop when the upper water temperature reaches the set temperature, while the lower water temperature has not been heated to the required temperature, resulting in a significant reduction in the actual hot water supply of the water tank.

[0088] In this embodiment, by calculating the water temperature difference between the upper water temperature and the lower water temperature, the temperature difference situation of the hot water inside the water tank can be determined, and the current opening is corrected according to the water temperature difference and the discharge superheat degree. The working reliability situation of the heat pump system can be determined through the discharge superheat degree, and the actual heating situation of the hot water inside the water tank can be determined through the water temperature difference. Combining the water temperature difference and the discharge superheat degree can better perform coupled control on the current opening of the electronic expansion valve, so that the current opening of the electronic expansion valve can fall within a suitable opening range, thereby better improving the uneven hot water heating situation inside the water tank, being beneficial to improving the hot water output rate of the heat pump system, and being convenient to better meet the actual hot water use requirements of users.

[0089] As Figure 4 shown, in the above control method of the heat pump system, in step S220, correcting the current opening according to the water temperature difference and the discharge superheat degree may include, but is not limited to, step S310 to step S330:

[0090] Step S310: When the water temperature difference is greater than a first preset value and the exhaust superheat is greater than a second preset value, increase the current opening degree;

[0091] Step S320: When the water temperature difference is greater than a first preset value, and the exhaust superheat is greater than a third preset value and less than or equal to the second preset value, maintain the current opening degree;

[0092] Step S330: When the water temperature difference is greater than a first preset value and the exhaust superheat is less than or equal to the third preset value, decrease the current opening degree.

[0093] Wherein, the second preset value is greater than the third preset value.

[0094] In this embodiment, when it is detected that the water temperature difference is greater than the first preset value, it means that the water temperature difference between the upper water temperature and the lower water temperature of the water tank is too large. In this case, when the exhaust superheat is greater than the second preset value, it is considered that the current exhaust superheat is too large, and the current opening degree of the electronic expansion valve can be increased, which can increase the refrigerant flow rate in the refrigerant circulation loop, thereby effectively improving the heat exchange of the lower water in the water tank, and then reducing the water temperature difference inside the water tank and effectively improving the hot water output rate of the heat pump system; when the exhaust superheat is greater than the third preset value and less than or equal to the second preset value, it is considered that the current exhaust superheat is within a suitable range and meets the reliability requirements of the heat pump system, and the current opening degree can be maintained, that is, there is no need to adjust the current opening degree of the electronic expansion valve; when the exhaust superheat is less than or equal to the third preset value, it is considered that the current exhaust superheat is too small. If the exhaust superheat is not enough, there is a risk of liquid return, which affects the reliability of the compressor operation. Therefore, the current opening degree of the electronic expansion valve can be reduced, thereby increasing the exhaust superheat and ensuring the stable and reliable operation of the heat pump system.

[0095] It can be understood that, when the water temperature difference is greater than the first preset value, the current opening degree of the electronic expansion valve is determined whether to be corrected based on the exhaust superheat. When it is determined that the exhaust superheat is too large and it is considered that the exhaust temperature of the compressor has a surplus at this time, the situation of too large water temperature difference can be preferentially solved. By increasing the current opening degree of the electronic expansion valve, the exhaust temperature of the compressor can be appropriately reduced, thereby slowing down the rate of condensation heat exchange of the upper water in the water tank, making more refrigerant flow to the lower part of the water tank, thereby accelerating the rate of condensation heat exchange of the lower water in the water tank, and then being able to reduce the water temperature difference inside the water tank, which is beneficial to improving the uniformity of the water temperature inside the water tank.

[0096] It should be noted that when the water temperature difference is greater than the first preset value and the exhaust superheat degree is determined to be too small, in order to avoid the risk of liquid return, the operation reliability of the compressor can be prioritized. By reducing the current opening degree of the electronic expansion valve, the exhaust temperature of the compressor can be appropriately increased, thereby increasing the exhaust superheat degree and ensuring the stable and reliable operation of the heat pump system.

[0097] In the control method of the above heat pump system, when the water temperature difference is greater than the first preset value and the exhaust superheat degree is greater than the second preset value, increasing the current opening degree in step S310 includes:

[0098] Adding a preset first opening degree adjustment value on the basis of the current opening degree;

[0099] Or, multiplying the current opening degree by a preset first opening degree adjustment coefficient to increase the current opening degree, and the first opening degree adjustment coefficient is greater than 1.

[0100] In this embodiment, when the water temperature difference is greater than the first preset value and the exhaust superheat degree is greater than the second preset value, it means that the water temperature difference inside the water tank is too large and the exhaust superheat degree is too large. Then, a preset first opening degree adjustment value can be added on the basis of the current opening degree to increase the current opening degree of the electronic expansion valve, or the current opening degree can be multiplied by a preset first opening degree adjustment coefficient to increase the current opening degree of the electronic expansion valve. By increasing the current opening degree, the water temperature difference inside the water tank can be reduced, and the hot water output rate of the heat pump system can be effectively improved.

[0101] It should be noted that the first opening degree adjustment value is a positive value, the first opening degree adjustment coefficient is greater than 1, and both the first opening degree adjustment value and the first opening degree adjustment coefficient are used to correct the current opening degree of the electronic expansion valve. The specific values of the first opening degree adjustment value and the first opening degree adjustment coefficient can be set according to actual needs, and the embodiments of the present invention do not make specific limitations.

[0102] In the control method of the above heat pump system, when the water temperature difference is greater than the first preset value and the exhaust superheat degree is less than or equal to the third preset value, reducing the current opening degree in step S330 includes:

[0103] Subtracting a preset second opening degree adjustment value from the current opening degree;

[0104] Or, multiplying the current opening degree by a preset second opening degree adjustment coefficient to reduce the current opening degree, and the second opening degree adjustment coefficient is greater than 0 and less than 1.

[0105] In this embodiment, when the water temperature difference is greater than the first preset value and the exhaust superheat degree is less than or equal to the third preset value, it indicates that the water temperature difference inside the water tank is too large and the exhaust superheat degree is insufficient. Then, the current opening of the electronic expansion valve can be reduced by subtracting a preset second opening adjustment value from the current opening, or the current opening can be multiplied by a preset second opening adjustment coefficient to reduce the current opening of the electronic expansion valve. By reducing the current opening, the exhaust superheat degree can be increased to ensure the stable and reliable operation of the heat pump system.

[0106] It should be noted that the second opening adjustment value is a positive value, the second opening adjustment coefficient is greater than 0 and less than 1. Both the second opening adjustment value and the second opening adjustment coefficient are used to correct the current opening of the electronic expansion valve. The specific values of the second opening adjustment value and the second opening adjustment coefficient can be set according to actual needs, and the embodiments of the present invention do not make specific limitations.

[0107] As Figure 5 shown, in the above control method of the heat pump system, when correcting the current opening according to the water temperature difference and the exhaust superheat degree in step S220, it further includes but is not limited to step S410 and step S420:

[0108] Step S410: When the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is greater than the third preset value, maintain the current opening;

[0109] Step S420: When the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is less than or equal to the third preset value, reduce the current opening.

[0110] In this embodiment, when it is detected that the water temperature difference is less than or equal to the first preset value, it indicates that the water temperature difference is within a reasonable range. In this case, when the exhaust superheat degree is greater than the third preset value, it is considered that the exhaust superheat degree is still within the range allowed by the heat pump system. Although the exhaust superheat degree is slightly large at this time, it does not affect the working reliability of the heat pump system. At the same time, since the water temperature difference is already within a reasonable range, there is no need to further adjust the water temperature inside the water tank, so the current opening is maintained, that is, there is no need to adjust the current opening of the electronic expansion valve; when the exhaust superheat degree is less than or equal to the third preset value, it is considered that the current exhaust superheat degree is too small. If the exhaust superheat degree is insufficient, it will affect the running reliability of the compressor. Then, the current opening of the electronic expansion valve can be reduced, so that the exhaust superheat degree can be increased to ensure the stable and reliable operation of the heat pump system.

[0111] In the above control method of the heat pump system, when the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is less than or equal to the third preset value, reducing the current opening in step S420 includes:

[0112] Subtracting a preset third opening adjustment value from the current opening;

[0113] Alternatively, multiply the current opening degree by a preset third opening degree adjustment coefficient to reduce the current opening degree, where the third opening degree adjustment coefficient is greater than 0 and less than 1.

[0114] In this embodiment, when the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is less than or equal to the third preset value, it indicates that the water temperature difference is within a reasonable range and the exhaust superheat degree is insufficient. Then, the current opening degree of the electronic expansion valve can be reduced by subtracting a preset third opening degree adjustment value from the current opening degree, or the current opening degree of the electronic expansion valve can be reduced by multiplying the current opening degree by a preset third opening degree adjustment coefficient. By reducing the current opening degree, the exhaust superheat degree can be increased, ensuring the stable and reliable operation of the heat pump system.

[0115] It should be noted that the third opening degree adjustment value is a positive value, the third opening degree adjustment coefficient is greater than 0 and less than 1, and both the third opening degree adjustment value and the third opening degree adjustment coefficient are used to correct the current opening degree of the electronic expansion valve. The specific values of the third opening degree adjustment value and the third opening degree adjustment coefficient can be set according to actual needs, and are not specifically limited in the embodiments of the present invention.

[0116] In one embodiment, if the calculated current opening degree is greater than the preset maximum opening degree of the electronic expansion valve, the current opening degree of the electronic expansion valve is no longer adjusted, and the electronic expansion valve can be directly controlled to operate at the maximum opening degree; if the calculated current opening degree is less than the preset minimum opening degree of the electronic expansion valve, the current opening degree of the electronic expansion valve is no longer adjusted, and the electronic expansion valve can be directly controlled to operate at the minimum opening degree. It can be understood that by controlling the current opening degree of the electronic expansion valve within the range between the minimum opening degree and the maximum opening degree, the reliability of the electronic expansion valve can be ensured.

[0117] As Figure 6 shown, in the control method of the above heat pump system, obtaining the exhaust superheat degree according to the upper water temperature, the lower water temperature, and the exhaust temperature in step S120 includes, but is not limited to, step S510 and step S520:

[0118] Step S510: Calculate the average water temperature of the upper water temperature and the lower water temperature;

[0119] Step S520: Subtract the average water temperature from the exhaust temperature to obtain the exhaust superheat degree.

[0120] In this embodiment, the average water temperature of the upper water temperature and the lower water temperature is calculated. By using the average water temperature, it can be closer to the saturation temperature corresponding to the compressor. Then, subtracting the average water temperature from the exhaust temperature can obtain the exhaust superheat degree, without the need to additionally set a pressure sensor, which can effectively save costs. In addition, since the exhaust superheat degree is obtained in this way, it can better reflect the hot water heating situation inside the water tank, so as to better meet the hot water usage needs of users.

[0121] In the control method of the above heat pump system, before obtaining the current opening degree of the electronic expansion valve in step S110, the control method of the heat pump system further includes, but is not limited to, step S610:

[0122] Step S610: Obtain the superheat of the suction gas, and control the current opening degree of the electronic expansion valve according to the superheat of the suction gas so that the superheat of the suction gas falls within a preset range; wherein, the superheat of the suction gas is obtained by subtracting the evaporation temperature of the evaporator from the suction gas temperature of the compressor.

[0123] In this embodiment, first, the current opening degree of the electronic expansion valve is controlled according to the superheat of the suction gas, so that the superheat of the suction gas falls within a preset range. By preferentially adjusting the current opening degree of the electronic expansion valve using the superheat of the suction gas, the opening degree adjustment efficiency can be improved, so that the current opening degree of the electronic expansion valve can quickly reach the opening degree range corresponding to the normal operation requirements of the heat pump system. Furthermore, by correcting the current opening degree according to the upper water temperature, lower water temperature, and superheat of the exhaust gas, the problem of uneven hot water heating inside the water tank can be solved. In addition, by obtaining the superheat of the suction gas by subtracting the evaporation temperature of the evaporator from the suction gas temperature of the compressor, the cost can be greatly reduced.

[0124] It should be noted that different from the method of solely controlling the current opening degree of the electronic expansion valve by the superheat of the suction gas, in the embodiment of the present invention, by adding the upper water temperature, lower water temperature of the water tank, and the exhaust gas temperature of the compressor, and correcting the current opening degree of the electronic expansion valve according to the upper water temperature, lower water temperature, and superheat of the exhaust gas, not only the reliable operation of the compressor can be ensured, but also the uniformity of the water temperature inside the water tank can be effectively improved, avoiding the situation of excessive water temperature change and insufficient hot water volume during the actual use by users, which is beneficial to improving the user experience.

[0125] As Figure 7 shown, in the control method of the above heat pump system, controlling the current opening degree of the electronic expansion valve according to the superheat of the suction gas in step S610 includes, but is not limited to, step S710 and step S720:

[0126] Step S710: When the superheat of the suction gas is greater than the upper limit value of the preset range, increase the current opening degree of the electronic expansion valve;

[0127] Step S720: When the superheat of the suction gas is less than the lower limit value of the preset range, decrease the current opening degree of the electronic expansion valve.

[0128] In this embodiment, when the suction superheat degree is greater than the upper limit value of the preset range, indicating that the current suction superheat degree is too large, the current opening degree of the electronic expansion valve is increased, which can increase the refrigerant flow rate in the refrigerant circulation loop, thereby appropriately reducing the suction superheat degree and ensuring that the suction superheat degree can fall within the preset range; when the suction superheat degree is less than the lower limit value of the preset range, indicating that the current suction superheat degree is too small, the current opening degree of the electronic expansion valve is reduced, which can reduce the refrigerant flow rate in the refrigerant circulation loop, thereby appropriately increasing the suction superheat degree and ensuring that the suction superheat degree can fall within the preset range; by making the suction superheat degree within the preset range, the reliability of the heat pump system operation can be ensured.

[0129] In one embodiment, after the electronic expansion valve operates at the current actual opening degree for a preset duration, the current opening degree, the upper water temperature of the water tank, the lower water temperature, and the exhaust gas temperature of the compressor are acquired again, and the new exhaust superheat degree is calculated. The current opening degree is corrected according to the new upper water temperature, the new lower water temperature, and the new exhaust superheat degree, which can timely adjust the operation state of the electronic expansion valve, avoid the situation of too large water temperature change and insufficient hot water volume during the actual use by the user, and is beneficial to improving the user experience.

[0130] To more clearly elaborate on the control method of the heat pump system of the present invention, the following will be further introduced with an overall embodiment.

[0131] As Figure 8 shown, the control method of the heat pump system of the present invention is specifically as follows:

[0132] 1. Acquire the suction superheat degree;

[0133] 2. Control the current opening degree of the electronic expansion valve according to the suction superheat degree so that the suction superheat degree falls within the preset range;

[0134] 3. Acquire the current opening degree EXV1, the upper water temperature Twater_U of the water tank, the lower water temperature Twater_L, and the exhaust gas temperature Tp of the compressor;

[0135] 4. Calculate the exhaust superheat degree; specifically, the average water temperature of the upper water temperature and the lower water temperature can be calculated, and the exhaust superheat degree is obtained by subtracting the average water temperature from the exhaust gas temperature. The exhaust superheat degree can be expressed as Tp - Ave{Twater_U, Twater_L}, where Ave{Twater_U, Twater_L} represents the average water temperature;

[0136] 5. Calculate the water temperature difference between the upper water temperature and the lower water temperature; among them, the water temperature difference can be expressed as Twater_U - Twater_L;

[0137] 6. Compare the temperature difference of the water temperature with the value of A; if Twater_U - Twater_L > A, it means the temperature difference of the water temperature is too large, and step 7 is executed; otherwise, step 12 is executed; where A is the first preset value;

[0138] 7. Compare the superheat of the exhaust gas with the value of C; if Tp - Ave{Twater_U, Twater_L} > C, step 8 is executed; otherwise, step 9 is executed; where C is the second preset value;

[0139] 8. EXV2 = EXV1 + K1; where K1 represents the first opening adjustment value, and EXV2 is the corrected current opening; by increasing K1 on the basis of EXV1, the current opening of the electronic expansion valve can be increased;

[0140] 9. Compare the superheat of the exhaust gas with the value of B; if Tp - Ave{Twater_U, Twater_L} ≤ B, step 10 is executed; otherwise, step 11 is executed; where B is the third preset value;

[0141] 10. EXV2 = EXV1 - K2; where K2 represents the second opening adjustment value, and EXV2 is the corrected current opening; by subtracting K2 from EXV1, the current opening of the electronic expansion valve can be decreased;

[0142] 11. Maintain EXV1; it should be noted that maintaining EXV1 means that there is no need to adjust the current opening of the electronic expansion valve;

[0143] 12. Compare the superheat of the exhaust gas with the value of B; if Tp - Ave{Twater_U, Twater_L} ≤ B, step 13 is executed; otherwise, step 14 is executed;

[0144] 13. EXV2 = EXV1 - K3; where K3 represents the third opening adjustment value, and EXV2 is the corrected current opening; by subtracting K3 from EXV1, the current opening of the electronic expansion valve can be decreased;

[0145] 14. Maintain EXV1; it should be noted that maintaining EXV1 means that there is no need to adjust the current opening of the electronic expansion valve.

[0146] Specifically, the value range of A is preferably 8°C to 12°C, the value range of B is preferably 8°C to 12°C, and the value range of C is preferably 12°C to 20°C, where C > B. It should be noted that the values of A, B, and C can be set accordingly according to the type of the compressor, and the embodiments of the present invention do not make specific limitations.

[0147] The control method of the heat pump system provided by this embodiment preferentially controls the current opening degree of the electronic expansion valve according to the superheat degree of the return gas, so that the superheat degree of the return gas falls within a preset range, and then corrects and adjusts the current opening degree according to the upper water temperature, the lower water temperature and the superheat degree of the exhaust gas, which can not only ensure the reliable operation of the compressor, but also effectively improve the uniformity of the water temperature inside the water tank. Specifically, in the case where the water temperature difference of the water tank is detected to be too large, if the superheat degree of the exhaust gas is too large, the current opening degree of the electronic expansion valve can be appropriately increased, so as to reduce the water temperature difference inside the water tank and effectively improve the hot water output rate of the heat pump system; if the superheat degree of the exhaust gas is within a suitable range, there is no need to adjust the current opening degree of the electronic expansion valve; if the superheat degree of the exhaust gas is too small, the current opening degree of the electronic expansion valve can be reduced, so as to increase the superheat degree of the exhaust gas and ensure the stable and reliable operation of the heat pump system; in the case where the water temperature difference of the water tank is detected to be within a reasonable range, if the superheat degree of the exhaust gas is slightly large, since the water temperature difference is already within a reasonable range, there is no need to further adjust the water temperature inside the water tank, that is, there is no need to adjust the current opening degree of the electronic expansion valve; if the superheat degree of the exhaust gas is too small, the current opening degree of the electronic expansion valve can be reduced, so as to ensure the stable and reliable operation of the heat pump system.

[0148] As Figure 9 shown, the second aspect embodiment of the present invention provides an operation control device 900, including a memory 910, a processor 920, and a computer program stored on the memory 910 and operable on the processor 920; the processor 920 and the memory 910 can be connected through a bus or other means, Figure 9 and an example of connection through a bus is shown. The processor 920 executes the above computer program to implement the control method of the heat pump system in the first aspect embodiment as above. For example, execute the Figure 2 method steps S110 to S130 in the above description, Figure 3 method steps S210 and S220 in the above description, Figure 4 method steps S310 to S330 in the above description, Figure 5 method steps S410 and S420 in the above description, Figure 6 method steps S510 and S520 in the above description, Figure 7 method steps S710 and S720 in the above description, and Figure 8Method steps. The superheat degree of exhaust can be obtained based on the upper water temperature, lower water temperature inside the water tank, and the exhaust temperature of the compressor, which can make the superheat degree of exhaust reflect both the working reliability of the heat pump system and fully consider the hot water heating inside the water tank, and correct the current opening degree of the electronic expansion valve according to the upper water temperature, lower water temperature, and superheat degree of exhaust. Since the upper water temperature, lower water temperature, and superheat degree of exhaust are added to correct and adjust the current opening degree, comprehensively considering the water temperature stratification inside the water tank and the influence of the superheat degree of exhaust on the reliability of the heat pump system, it can not only ensure the reliable operation of the heat pump system, but also effectively improve the uniformity of the water temperature inside the water tank, thereby improving the hot water output rate of the heat pump system, better meeting the actual hot water usage needs of users, and being beneficial to improving the user experience.

[0149] The third aspect embodiment of the present invention provides a heat pump system, including an operation control device as in the second aspect embodiment above. The heat pump system of the embodiment of the present invention can obtain the superheat degree of exhaust based on the upper water temperature, lower water temperature inside the water tank, and the exhaust temperature of the compressor, which can make the superheat degree of exhaust reflect both the working reliability of the heat pump system and fully consider the hot water heating inside the water tank, and correct the current opening degree of the electronic expansion valve according to the upper water temperature, lower water temperature, and superheat degree of exhaust. Since the upper water temperature, lower water temperature, and superheat degree of exhaust are added to correct and adjust the current opening degree, comprehensively considering the water temperature stratification inside the water tank and the influence of the superheat degree of exhaust on the reliability of the heat pump system, it can not only ensure the reliable operation of the heat pump system, but also effectively improve the uniformity of the water temperature inside the water tank, thereby improving the hot water output rate of the heat pump system, better meeting the actual hot water usage needs of users, and being beneficial to improving the user experience.

[0150] The fourth aspect embodiment of the present invention provides a computer-readable storage medium, which stores computer-executable instructions. The computer-executable instructions can be used to make a computer execute the control method of the heat pump system in the first aspect embodiment above. For example, execute the method steps S110 to S130 described above Figure 2 in the method steps S110 to S130, Figure 3 in the method steps S210 and S220, Figure 4 in the method steps S310 to S330, Figure 5 in the method steps S410 and S420, Figure 6 in the method steps S510 and S520, Figure 7 in the method steps S710 and S720, and Figure 8Method steps. The superheat degree of the exhaust can be obtained based on the upper water temperature, lower water temperature inside the water tank, and the exhaust temperature of the compressor, so that the superheat degree of the exhaust can not only reflect the working reliability of the heat pump system, but also fully consider the hot water heating situation inside the water tank, and correct the current opening degree of the electronic expansion valve according to the upper water temperature, lower water temperature, and superheat degree of the exhaust. Since the upper water temperature, lower water temperature, and superheat degree of the exhaust are added to correct and adjust the current opening degree, the temperature stratification situation inside the water tank and the influence of the superheat degree of the exhaust on the reliability of the heat pump system are comprehensively considered. It can not only ensure the reliable operation of the heat pump system, but also effectively improve the uniformity of the water temperature inside the water tank, thereby increasing the hot water output rate of the heat pump system, better meeting the actual hot water usage needs of users, and being beneficial to improving the user experience.

[0151] Those of ordinary skill in the art can understand that all or some of the steps and systems disclosed in the above methods can be implemented as software, firmware, hardware, and their appropriate combinations. Some physical components or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include a computer storage medium or a non-transitory medium and a communication medium or a transitory medium. As is well known to those of ordinary skill in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory, or other memory technologies, CD-ROM, digital versatile disc (DVD), or other optical disc storage, magnetic cassette, tape, magnetic disk storage, or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, as is well known to those of ordinary skill in the art, communication media typically includes computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and can include any information delivery medium.

[0152] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the technical field, various changes can be made without departing from the gist of the present invention.

Claims

1. A control method for a heat pump system, characterized in that, The heat pump system includes a compressor, a water tank, and an electronic expansion valve. The water tank is provided with a heat exchange coil. The exhaust port of the compressor is connected to the inlet of the heat exchange coil, and the outlet of the heat exchange coil is connected to the suction port of the compressor through the electronic expansion valve. The control method includes: Obtain the current opening degree of the electronic expansion valve; Obtain the upper water temperature, lower water temperature of the water tank, and the exhaust temperature of the compressor, and obtain the exhaust superheat degree according to the upper water temperature, the lower water temperature, and the exhaust temperature; Correct the current opening degree according to the upper water temperature, the lower water temperature, and the exhaust superheat degree; Wherein: The correcting the current opening degree according to the upper water temperature, the lower water temperature, and the exhaust superheat degree includes: Calculate the water temperature difference between the upper water temperature and the lower water temperature; Correct the current opening degree according to the water temperature difference and the exhaust superheat degree; The obtaining the exhaust superheat degree according to the upper water temperature, the lower water temperature, and the exhaust temperature includes: Calculate the average water temperature of the upper water temperature and the lower water temperature; Subtract the average water temperature from the exhaust temperature to obtain the exhaust superheat degree.

2. The control method according to claim 1, wherein The correcting the current opening degree according to the water temperature difference and the exhaust superheat degree includes: When the water temperature difference is greater than a first preset value and the exhaust superheat degree is greater than a second preset value, increase the current opening degree; When the water temperature difference is greater than the first preset value, and the exhaust superheat degree is greater than a third preset value and less than or equal to the second preset value, maintain the current opening degree; When the water temperature difference is greater than the first preset value and the exhaust superheat degree is less than or equal to the third preset value, decrease the current opening degree; Wherein, the second preset value is greater than the third preset value.

3. The control method according to claim 2, wherein When the water temperature difference is greater than the first preset value and the exhaust superheat degree is greater than the second preset value, the increasing the current opening degree includes: Increase a preset first opening degree adjustment value on the basis of the current opening degree; Or, multiply the current opening degree by a preset first opening degree adjustment coefficient to increase the current opening degree, and the first opening degree adjustment coefficient is greater than 1.

4. The control method according to claim 2, wherein When the water temperature difference is greater than the first preset value and the exhaust superheat degree is less than or equal to the third preset value, the decreasing the current opening degree includes: Subtract a preset second opening degree adjustment value from the current opening degree; Or, multiply the current opening degree by a preset second opening degree adjustment coefficient to decrease the current opening degree, and the second opening degree adjustment coefficient is greater than 0 and less than 1.

5. The control method according to claim 1, characterized in that The correcting the current opening degree according to the water temperature difference and the exhaust superheat degree further includes: When the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is greater than the third preset value, maintain the current opening degree; When the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is less than or equal to the third preset value, decrease the current opening degree.

6. The control method according to claim 5, wherein When the water temperature difference is less than or equal to the first preset value and the exhaust superheat degree is less than or equal to the third preset value, the decreasing the current opening degree includes: Subtract a preset third opening degree adjustment value from the current opening degree; Alternatively, multiply the current opening degree by a preset third opening degree adjustment coefficient to reduce the current opening degree, where the third opening degree adjustment coefficient is greater than 0 and less than 1.

7. The control method according to claim 1, characterized in that Before obtaining the current opening degree of the electronic expansion valve, the control method further includes: Obtaining the superheat of the return gas, and controlling the current opening degree of the electronic expansion valve according to the superheat of the return gas so that the superheat of the return gas falls within a preset range; where the superheat of the return gas is obtained by subtracting the evaporation temperature of the evaporator from the return gas temperature of the compressor.

8. The control method according to claim 7, characterized in that Controlling the current opening degree of the electronic expansion valve according to the superheat of the return gas includes: When the superheat of the return gas is greater than the upper limit value of the preset range, increasing the current opening degree of the electronic expansion valve; When the superheat of the return gas is less than the lower limit value of the preset range, reducing the current opening degree of the electronic expansion valve.

9. An operation control device, characterized in that, Comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the program to implement the control method according to any one of claims 1 to 8.

10. A heat pump system, characterized in that, Comprising the operation control device according to claim 9.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to execute the control method according to any one of claims 1 to 8.

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