Heat pump water heater electronic expansion valve control method, device and system and water heater

Abstract

The invention discloses a heat pump water heater electronic expansion valve control method, device and system and a water heater, and belongs to the field of heat pump systems. During starting, the initial electronic expansion valve step number of the electronic expansion valve is determined according to the environment temperature and the water temperature of the water tank, and the step number of the electronic expansion valve is controlled to be the initial electronic expansion valve step number. In this way, it is guaranteed that the initial electronic expansion valve step number of the electronic expansion valve conforms to the current working condition, and the reliability and performance of the heat pump system during starting are guaranteed. After the step number for controlling the electronic expansion valve is the initial step number of the electronic expansion valve and the duration is the first preset duration, the electronic expansion valve is adjusted according to the preset control scheme, and when the electronic expansion valve is adjusted according to the preset control scheme, the adjustment interval duration of the electronic expansion valve is determined based on the actual valve step number and the target valve step number; the electronic expansion valve can be timely adjusted, and the system is fast and stable.

Description

Technical Field

[0001] The present application relates to the technical field of heat pump systems, and in particular, to a heat pump water heater electronic expansion valve control method, device, system and water heater. Background Art

[0002] In a variable frequency heat pump water heater, when an electronic expansion valve is used to regulate and control the heat pump system, an initial valve opening is usually required at each startup. After the heat pump system runs for a period of time according to the initial valve opening, it enters the normal regulation process and performs real-time adjustments to ensure stable and efficient operation of the heat pump system.

[0003] Currently in heat pump water heaters, the electronic expansion valve of the heat pump system is usually set to a fixed value after startup and its adjustment cycle during normal adjustment is also a fixed value, which cannot meet actual needs. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present application provides a heat pump water heater electronic expansion valve control method, device, system and water heater to solve the problem that in the current heat pump water heater, the electronic expansion valve of the heat pump system is usually set to a fixed value after startup and its adjustment period is also a fixed value during normal adjustment, which cannot meet actual needs.

[0005] The technical solution adopted by this application to solve its technical problem is:

[0006] In a first aspect, a method for controlling an electronic expansion valve of a heat pump water heater is provided, comprising:

[0007] When receiving the power-on command, obtain the ambient temperature and the water temperature of the water tank;

[0008] determining an initial electronic expansion valve step number of the electronic expansion valve based on the ambient temperature and the water temperature of the water tank;

[0009] After the number of steps of controlling the electronic expansion valve is equal to the initial number of steps of the electronic expansion valve and the duration is equal to the first preset duration, adjusting the electronic expansion valve according to a preset control scheme;

[0010] When the electronic expansion valve is adjusted according to a preset control scheme, the adjustment interval duration of the electronic expansion valve is determined based on the actual valve steps and the target valve steps of the electronic expansion valve, and the electronic expansion valve is adjusted according to the adjustment interval duration.

[0011] Further, determining the adjustment interval duration of the electronic expansion valve based on the actual valve step number and the target valve step number of the electronic expansion valve includes:

[0012] Calculating the step difference between the actual valve step number and the target valve step number at intervals of a second preset time length;

[0013] If the absolute value of the step difference is greater than the preset step difference, the adjustment interval of the electronic expansion valve is determined to be the first preset adjustment interval; if the absolute value of the step difference is less than or equal to the preset step difference, the adjustment interval of the electronic expansion valve is determined to be the second preset adjustment interval;

[0014] The first preset adjustment interval duration is shorter than the second preset adjustment interval duration.

[0015] Further, determining the adjustment interval duration of the electronic expansion valve based on the actual valve steps and the target valve steps of the electronic expansion valve includes:

[0016] Calculating the step difference between the actual valve step number and the target valve step number at intervals of a second preset time length;

[0017] The adjustment interval duration of the electronic expansion valve is calculated using the following formula:

[0018] Adjustment interval length = 1 / absolute value of step difference*A, where A is the preset basic coefficient.

[0019] Further, the obtaining of the ambient temperature and the water temperature of the water tank includes:

[0020] Obtaining the stabilization time of the ambient temperature and the water temperature of the water tank;

[0021] The ambient temperature and the water temperature of the water tank are obtained when the stabilization time of the ambient temperature and the water temperature of the water tank is respectively greater than the preset stabilization time.

[0022] Furthermore, it also includes:

[0023] When the difference between the current ambient temperature and the previous ambient temperature is within the preset ambient temperature difference range, the ambient temperature is judged to be stable; when the difference between the current tank water temperature and the previous tank water temperature is within the preset tank water temperature difference range, the tank water temperature is judged to be stable.

[0024] Furthermore, it also includes:

[0025] When the ratio of the current ambient temperature to the previous ambient temperature is within the preset ambient temperature ratio range, the ambient temperature is judged to be stable; when the ratio of the current tank water temperature to the previous tank water temperature is within the preset tank water temperature ratio range, the tank water temperature is judged to be stable.

[0026] Further, the determining of the initial electronic expansion valve step number of the electronic expansion valve based on the ambient temperature and the water temperature of the water tank comprises:

[0027] Determining the ambient temperature interval based on the ambient temperature, and determining the water tank water temperature interval based on the water tank water temperature;

[0028] An initial electronic expansion valve step number of the electronic expansion valve is determined according to a preset corresponding relationship, wherein in the preset corresponding relationship, a group of ambient temperature intervals and water tank water temperature intervals correspond to one electronic expansion valve step number.

[0029] In a second aspect, a heat pump water heater electronic expansion valve control device is provided, comprising:

[0030] The temperature parameter acquisition module is used to obtain the ambient temperature and the water temperature of the water tank when receiving the power-on command;

[0031] An initial step number determination module, used to determine an initial electronic expansion valve step number of the electronic expansion valve based on the ambient temperature and the water temperature of the water tank;

[0032] A normal operation control module, configured to adjust the electronic expansion valve according to a preset control scheme after the number of steps of controlling the electronic expansion valve is equal to the initial number of steps of the electronic expansion valve and the duration is equal to a first preset duration;

[0033] An adjustment interval determination module is used to determine the adjustment interval duration of the electronic expansion valve based on the actual valve steps and the target valve steps of the electronic expansion valve when adjusting the electronic expansion valve according to a preset control scheme, and adjust the electronic expansion valve according to the adjustment interval duration.

[0034] In a third aspect, a heat pump water heater electronic expansion valve control system is provided, comprising:

[0035] at least one processor and at least one memory;

[0036] The memory stores executable instructions of the processor;

[0037] The processor is configured to execute the above-mentioned heat pump water heater electronic expansion valve control method.

[0038] In a fourth aspect, a water heater is provided, which uses the above-mentioned heat pump water heater electronic expansion valve control method.

[0039] Beneficial effects:

[0040] The technical solution of the present application provides a method for controlling an electronic expansion valve of a heat pump water heater. When the system is turned on, the initial number of steps of the electronic expansion valve is determined according to the ambient temperature and the water temperature of the water tank, and the number of steps of the electronic expansion valve is controlled to be the initial number of steps of the electronic expansion valve. In this way, the initial number of steps of the electronic expansion valve is ensured to meet the current working conditions, and the reliability and performance of the heat pump system when it is turned on are ensured. After the number of steps of the electronic expansion valve is controlled to be the initial number of steps of the electronic expansion valve and the duration is the first preset duration, the electronic expansion valve is adjusted according to the preset control scheme. When the electronic expansion valve is adjusted according to the preset control scheme, the adjustment interval duration of the electronic expansion valve is determined based on the actual number of steps of the valve and the target number of steps of the valve, so as to ensure that the electronic expansion valve is adjusted in a timely manner and the system is quickly stabilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 This is a flow chart of a heat pump water heater electronic expansion valve control method provided in an embodiment of the present application;

[0043] Figure 2 This is a specific heat pump water heater electronic expansion valve control flow chart provided in an embodiment of the present application;

[0044] Figure 3 It is a structural schematic diagram of an electronic expansion valve control device for a heat pump water heater provided in an embodiment of the present application;

[0045] Figure 4 It is a schematic diagram of the structure of an electronic expansion valve control system of a heat pump water heater provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application is described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other implementation methods obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0047] The operating conditions of existing heat pump water heaters vary greatly throughout the year. The number of steps of the electronic expansion valve at the time of startup under different conditions has a certain impact on the reliability and performance of the system. For the process of the electronic expansion valve adjusting from the initial valve step number to the normal valve step number level after startup, if the initial opening of the electronic expansion valve is too large, the heat pump system will have the risk of adjustment delay, suction and liquid, etc. If the initial opening of the electronic expansion valve is too small, the heat pump system will have the problems of too low low pressure, long time to establish balance, and performance deterioration.

[0048] During normal adjustment after startup, the adjustment period is a fixed value. If the adjustment period is set to be short, the adjustment will be frequent, resulting in unnecessary waste. If the adjustment period is set to be long, the adjustment will be slow under some working conditions, affecting the system's responsiveness.

[0049] To solve this problem, refer to Figure 1 , the embodiment of the present application provides a heat pump water heater electronic expansion valve control method, comprising:

[0050] S11: When receiving the power-on command, obtain the ambient temperature and the water tank temperature. The ambient temperature is the temperature obtained by the temperature sensor installed at the outdoor unit of the heat pump system. Since the outdoor unit is generally installed outdoors, the outdoor temperature can be directly used instead, that is, the outdoor temperature obtained by other equipment can be used as the ambient temperature. The water tank temperature is the temperature obtained by the temperature sensor installed in the water tank of the water heater.

[0051] As a preferred implementation of the present application, obtaining the ambient temperature and the water temperature of the water tank includes:

[0052] Obtaining the stabilization time of the ambient temperature and the water temperature of the water tank;

[0053] The ambient temperature and the water temperature in the water tank are obtained when the stabilization time of the ambient temperature and the water temperature in the water tank is greater than the preset stabilization time. That is, in order to ensure the accuracy of the subsequent initial electronic expansion valve steps, it is necessary to ensure that the obtained ambient temperature and the water temperature in the water tank are accurate. Therefore, it is necessary to obtain the ambient temperature and the water temperature in the water tank when they are stable.

[0054] In one embodiment, when the difference between the ambient temperature at a current moment and the ambient temperature at a previous moment is within a preset ambient temperature difference range, the ambient temperature is judged to be stable; when the difference between the water temperature of the water tank at a current moment and the water temperature of the water tank at a previous moment is within a preset water tank water temperature difference range, the water tank water temperature is judged to be stable.

[0055] In another embodiment, when the ratio of the ambient temperature at the current moment to the ambient temperature at the previous moment is within a preset ambient temperature ratio range, the ambient temperature is judged to be stable; when the ratio of the water temperature of the water tank at the current moment to the water temperature of the water tank at the previous moment is within a preset water tank water temperature ratio range, the water tank water temperature is judged to be stable.

[0056] It should be noted that, in general, the ambient temperature and water tank temperature are relatively stable after startup. At this time, the ambient temperature and water tank temperature at multiple times can be averaged, or the ambient temperature and water tank temperature at any time can be obtained (because the subsequent determination of the initial number of steps of the electronic expansion valve is determined based on the range of the ambient temperature and the water tank temperature, so the values ​​at different times are not exactly the same and do not affect the subsequent determination of the initial number of steps of the electronic expansion valve).

[0057] S12: determining an initial electronic expansion valve step number of the electronic expansion valve based on the ambient temperature and the water temperature of the water tank;

[0058] As a preferred implementation of the embodiment of the present application, determining the initial electronic expansion valve step number of the electronic expansion valve based on the ambient temperature and the water temperature of the water tank includes:

[0059] Determining the ambient temperature interval based on the ambient temperature, and determining the water tank water temperature interval based on the water tank water temperature;

[0060] An initial electronic expansion valve step number of the electronic expansion valve is determined according to a preset corresponding relationship, wherein in the preset corresponding relationship, a group of ambient temperature intervals and water tank water temperature intervals correspond to one electronic expansion valve step number.

[0061] Exemplarily, the preset corresponding relationship is a preset table, as shown in Table 1.

[0062] Table 1

[0063]

[0064] S13: After the number of steps of controlling the electronic expansion valve is equal to the initial number of steps of the electronic expansion valve and the duration is equal to the first preset duration, adjusting the electronic expansion valve according to a preset control scheme.

[0065] The preset control scheme adjusts the electronic expansion valve to determine the target valve step number of the electronic expansion valve according to certain parameters (such as suction pressure, ambient temperature, superheat, etc.), and then controls the opening of the electronic expansion valve to be the target valve step number. Because this application does not improve it, it is not limited to this. The parameters can be selected according to actual needs to determine the target valve step number.

[0066] S14: When adjusting the electronic expansion valve according to a preset control scheme, determining an adjustment interval duration of the electronic expansion valve based on an actual valve step number and a target valve step number of the electronic expansion valve, and adjusting the electronic expansion valve according to the adjustment interval duration.

[0067] Because in actual control, as the environment and working conditions change, the target valve steps will be adjusted continuously during the entire operation of the heat pump unit for the control strategy based on superheat; therefore, the target valve steps are not necessarily the same as the actual valve steps. If the target valve steps differ greatly from the actual valve steps, and the adjustment interval is long, the output of the heat pump system may not meet the demand.

[0068] Therefore, in one embodiment, determining the adjustment interval duration of the electronic expansion valve based on the actual valve step number and the target valve step number of the electronic expansion valve includes:

[0069] Calculating the step difference between the actual valve step number and the target valve step number at intervals of a second preset time length;

[0070] If the absolute value of the step difference is greater than the preset step difference, the adjustment interval of the electronic expansion valve is determined to be the first preset adjustment interval; if the absolute value of the step difference is less than or equal to the preset step difference, the adjustment interval of the electronic expansion valve is determined to be the second preset adjustment interval;

[0071] The first preset adjustment interval duration is shorter than the second preset adjustment interval duration.

[0072] In another embodiment, determining the adjustment interval duration of the electronic expansion valve based on the actual valve step number and the target valve step number of the electronic expansion valve includes:

[0073] Calculating the step difference between the actual valve step number and the target valve step number at intervals of a second preset time length;

[0074] The adjustment interval duration of the electronic expansion valve is calculated using the following formula:

[0075] Adjustment interval length = 1 / absolute value of step difference*A, where A is the preset basic coefficient.

[0076] In actual control, the adjustment interval length = 1 / absolute value of the step difference*A+B, where B is a preset constant.

[0077] The electronic expansion valve control method for a heat pump water heater provided in an embodiment of the present application determines the initial electronic expansion valve step number of the electronic expansion valve according to the ambient temperature and the water temperature of the water tank when the water is turned on, and controls the step number of the electronic expansion valve to be the initial electronic expansion valve step number. In this way, it is ensured that the initial electronic expansion valve step number of the electronic expansion valve meets the current working conditions, and the reliability and performance of the heat pump system when it is turned on are ensured. After the step number of the electronic expansion valve is controlled to be the initial electronic expansion valve step number and the duration is the first preset duration, the electronic expansion valve is adjusted according to the preset control scheme. When the electronic expansion valve is adjusted according to the preset control scheme, the adjustment interval duration of the electronic expansion valve is determined based on the actual valve step number and the target valve step number, so as to ensure that the electronic expansion valve is adjusted in time and the system is quickly stabilized.

[0078] In order to more clearly illustrate the present application scheme, a specific implementation method is provided below:

[0079] like Figure 2 As shown, the electronic expansion valve optimization control process mainly includes a two-level optimization control process, wherein the first-level optimization process mainly includes steps S101 to S105, and the second-level optimization process mainly includes steps S106 to S109. Among them, the first-level optimization process can achieve matching a more optimal initial valve step number of the electronic expansion valve according to different working conditions at the time of unit startup to optimize the operating state of the unit during the initial non-steady-state period. The second-level optimization process can achieve that during the operation of the unit, the electronic expansion valve can adapt to the adjustment speed according to the deviation between the actual valve step number and the target valve step number, so that the electronic expansion valve can reach an opening level suitable for the unit more quickly.

[0080] The specific implementation is as follows: When the unit is started, the electronic expansion valve control preferentially enters the first-level optimization.

[0081] Step S101: the unit detects the ambient temperature Th and the water tank temperature Ts.

[0082] Step S102: When it is detected that the ambient temperature Th remains stable for 10 seconds and the water temperature remains stable for 10 seconds, the process proceeds to step S103.

[0083] Step S103: If it is detected that the ambient temperature Th and the water temperature Ts do not meet the stability condition, proceed to step S102 to perform ambient temperature and water temperature detection.

[0084] In the step S103, the initial number of electronic expansion valve steps in the corresponding temperature range is selected according to Table 1 based on the detected stable ambient temperature Th and water temperature Ts, and then the next step S104 is entered.

[0085] Step S104: Detect the maintenance time of the initial valve steps of the electronic expansion valve, and enter step S105 when the maintenance time is greater than 200s.

[0086] Step S105: Control according to the normal operation logic of the electronic expansion valve. After entering the normal operation logic control of the electronic expansion valve in S105, the electronic expansion valve secondary optimization control is immediately entered.

[0087] Step S106: Detect the actual valve steps and the target valve steps of the electronic expansion valve every 5 seconds, and then proceed to step S107.

[0088] Step S107: Calculate the detected target valve steps and the actual valve steps. When the absolute difference between the two is greater than 10B, proceed to the next step S109; when the absolute difference between the target valve steps and the actual valve steps is less than or equal to 10B, proceed to the next step S108.

[0089] Step S108: The electronic expansion valve will adjust the valve steps at a frequency of 30s / time.

[0090] Step S109: the electronic expansion valve will adjust the valve steps at a frequency of 10s / time.

[0091] In the whole process of adjusting the electronic expansion valve, the maximum value of the initial electronic expansion valve step is controlled to be less than 95% of the total opening, and the minimum value is controlled to be greater than 20% of the total opening. The total opening refers to the maximum opening of the electronic expansion valve.

[0092] The specific heat pump water heater electronic expansion valve control method provided in the embodiment of the present application matches different initial valve steps of the electronic expansion valve according to different ambient temperatures and water temperature segments, and starts to enter normal regulation control according to the suction superheat after the initial valve step control is completed, wherein the maximum value of the initial valve step of the electronic expansion valve is controlled to be less than 95% of the total opening, and the minimum value is controlled to be greater than 20% of the total opening, and after the electronic expansion valve enters the normal control process, the valve step regulation rate is adjusted in real time according to the deviation between the actual valve step and the target valve step, and the electronic expansion valve optimization control method can enable the heat pump system to quickly establish a balance, so that the heat pump system can quickly enter a stable and reliable optimal operating state.

[0093] Based on the same inventive concept, Figure 3 As shown, the present application also provides a heat pump water heater electronic expansion valve control device 30, comprising:

[0094] The temperature parameter acquisition module 31 is used to acquire the ambient temperature and the water temperature of the water tank when receiving the power-on instruction; wherein, acquiring the ambient temperature and the water temperature of the water tank includes:

[0095] Obtaining the stabilization time of the ambient temperature and the water temperature of the water tank;

[0096] The ambient temperature and the water temperature of the water tank are obtained when the stabilization time of the ambient temperature and the water temperature of the water tank is respectively greater than the preset stabilization time.

[0097] In one embodiment, when the difference between the ambient temperature at a current moment and the ambient temperature at a previous moment is within a preset ambient temperature difference range, the ambient temperature is judged to be stable; when the difference between the water temperature of the water tank at a current moment and the water temperature of the water tank at a previous moment is within a preset water tank water temperature difference range, the water tank water temperature is judged to be stable.

[0098] In another embodiment, when the ratio of the ambient temperature at the current moment to the ambient temperature at the previous moment is within a preset ambient temperature ratio range, the ambient temperature is judged to be stable; when the ratio of the water temperature of the water tank at the current moment to the water temperature of the water tank at the previous moment is within a preset water tank water temperature ratio range, the water tank water temperature is judged to be stable.

[0099] An initial step number determination module 32, used to determine an initial electronic expansion valve step number of the electronic expansion valve based on the ambient temperature and the water temperature of the water tank;

[0100] Wherein, determining the initial electronic expansion valve step number of the electronic expansion valve based on the ambient temperature and the water temperature of the water tank includes:

[0101] Determining the ambient temperature interval based on the ambient temperature, and determining the water tank water temperature interval based on the water tank water temperature;

[0102] An initial electronic expansion valve step number of the electronic expansion valve is determined according to a preset corresponding relationship, wherein in the preset corresponding relationship, a group of ambient temperature intervals and water tank water temperature intervals correspond to one electronic expansion valve step number.

[0103] The normal operation control module 33 is used to adjust the electronic expansion valve according to a preset control scheme after the number of steps of controlling the electronic expansion valve is the initial number of steps of the electronic expansion valve and the duration is the first preset duration.

[0104] The adjustment interval determination module 34 is used to determine the adjustment interval duration of the electronic expansion valve based on the actual valve steps and the target valve steps of the electronic expansion valve when adjusting the electronic expansion valve according to a preset control scheme, and adjust the electronic expansion valve according to the adjustment interval duration.

[0105] In one embodiment, determining the adjustment interval duration of the electronic expansion valve based on the actual valve steps and the target valve steps of the electronic expansion valve includes:

[0106] Calculating the step difference between the actual valve step number and the target valve step number at intervals of a second preset time length;

[0107] If the absolute value of the step difference is greater than the preset step difference, the adjustment interval of the electronic expansion valve is determined to be the first preset adjustment interval; if the absolute value of the step difference is less than or equal to the preset step difference, the adjustment interval of the electronic expansion valve is determined to be the second preset adjustment interval;

[0108] The first preset adjustment interval duration is shorter than the second preset adjustment interval duration.

[0109] In another embodiment, determining the adjustment interval duration of the electronic expansion valve based on the actual valve steps and the target valve steps of the electronic expansion valve includes:

[0110] Calculating the step difference between the actual valve step number and the target valve step number at intervals of a second preset time length;

[0111] The adjustment interval duration of the electronic expansion valve is calculated using the following formula:

[0112] Adjustment interval length = 1 / absolute value of step difference*A, where A is the preset basic coefficient.

[0113] The electronic expansion valve control device for a heat pump water heater provided in an embodiment of the present application determines the initial electronic expansion valve step number of the electronic expansion valve according to the ambient temperature and the water temperature of the water tank when the device is turned on, and controls the step number of the electronic expansion valve to be the initial electronic expansion valve step number. This ensures that the initial electronic expansion valve step number of the electronic expansion valve meets the current working conditions, and ensures the reliability and performance of the heat pump system when it is turned on. After the step number of the electronic expansion valve is controlled to be the initial electronic expansion valve step number and the duration is the first preset duration, the electronic expansion valve is adjusted according to the preset control scheme. When the electronic expansion valve is adjusted according to the preset control scheme, the adjustment interval duration of the electronic expansion valve is determined based on the actual valve step number and the target valve step number, to ensure that the electronic expansion valve is adjusted in a timely manner and the system is quickly stabilized.

[0114] Based on the same inventive concept, Figure 4 As shown, the present application also provides a heat pump water heater electronic expansion valve control system 40, comprising:

[0115] at least one processor 41 and at least one memory 42;

[0116] The memory stores executable instructions of the processor;

[0117] The processor is configured to execute the heat pump water heater electronic expansion valve control method provided in the above embodiment.

[0118] The heat pump water heater electronic expansion valve control system provided in the embodiment of the present application stores executable instructions of the processor in a memory. When the executable instructions are executed, the processor can determine the initial electronic expansion valve step number of the electronic expansion valve according to the ambient temperature and the water temperature of the water tank when the system is turned on, and control the step number of the electronic expansion valve to be the initial electronic expansion valve step number. In this way, it is ensured that the initial electronic expansion valve step number of the electronic expansion valve meets the current working conditions, and the reliability and performance of the heat pump system when it is turned on are ensured. After the step number of the electronic expansion valve is controlled to be the initial electronic expansion valve step number and the duration is the first preset duration, the electronic expansion valve is adjusted according to the preset control scheme. When the electronic expansion valve is adjusted according to the preset control scheme, the adjustment interval duration of the electronic expansion valve is determined based on the actual valve step number and the target valve step number, so as to ensure that the electronic expansion valve is adjusted in time and the system is quickly stabilized.

[0119] Based on the same inventive concept, Figure 4 As shown, the present application also provides a water heater, which applies the electronic expansion valve control method of the heat pump water heater provided in the above embodiment.

[0120] The water heater provided by the present application, by applying the heat pump water heater electronic expansion valve control method provided by the above embodiment, can determine the initial electronic expansion valve step number of the electronic expansion valve according to the ambient temperature and the water temperature of the water tank when starting up, and control the step number of the electronic expansion valve to be the initial electronic expansion valve step number. In this way, it is ensured that the initial electronic expansion valve step number of the electronic expansion valve meets the current working conditions, and the reliability and performance of the heat pump system when starting up is ensured. After the step number of the electronic expansion valve is controlled to be the initial electronic expansion valve step number and the duration is the first preset duration, the electronic expansion valve is adjusted according to the preset control scheme. When the electronic expansion valve is adjusted according to the preset control scheme, the adjustment interval duration of the electronic expansion valve is determined based on the actual valve step number and the target valve step number, so as to ensure that the electronic expansion valve is adjusted in time and the system is quickly stabilized.

[0121] It should be noted that, in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0122] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

Claims

1. A heat pump water heater electronic expansion valve control method, characterized in that: include: When receiving the power-on command, obtain the ambient temperature and the water temperature of the water tank; Determining an initial electronic expansion valve step number of the electronic expansion valve based on the ambient temperature and the water temperature of the water tank; After the number of steps of controlling the electronic expansion valve is equal to the initial number of steps of the electronic expansion valve and the duration is equal to the first preset duration, adjusting the electronic expansion valve according to a preset control scheme; When the electronic expansion valve is adjusted according to a preset control scheme, the adjustment interval duration of the electronic expansion valve is determined based on the actual valve steps and the target valve steps of the electronic expansion valve, and the electronic expansion valve is adjusted according to the adjustment interval duration.

2. The method according to claim 1, characterized in that: The determining the adjustment interval duration of the electronic expansion valve based on the actual valve steps and the target valve steps of the electronic expansion valve comprises: Calculating the step difference between the actual valve step number and the target valve step number at intervals of a second preset time length; If the absolute value of the step difference is greater than the preset step difference, the adjustment interval of the electronic expansion valve is determined to be the first preset adjustment interval; if the absolute value of the step difference is less than or equal to the preset step difference, the adjustment interval of the electronic expansion valve is determined to be the second preset adjustment interval; The first preset adjustment interval duration is shorter than the second preset adjustment interval duration.

3. The method according to claim 1, characterized in that: The determining the adjustment interval duration of the electronic expansion valve based on the actual valve steps and the target valve steps of the electronic expansion valve comprises: Calculating the step difference between the actual valve step number and the target valve step number at intervals of a second preset time length; The adjustment interval duration of the electronic expansion valve is calculated using the following formula: Adjustment interval length = 1 / absolute value of step difference*A, where A is the preset basic coefficient.

4. The method according to claim 1, characterized in that: The step of obtaining the ambient temperature and the water temperature of the water tank includes: Obtaining the stabilization time of the ambient temperature and the water temperature of the water tank; The ambient temperature and the water temperature of the water tank are obtained when the stabilization time of the ambient temperature and the water temperature of the water tank is respectively greater than the preset stabilization time.

5. The method according to claim 4, characterized in that Also includes: When the difference between the current ambient temperature and the previous ambient temperature is within a preset ambient temperature difference range, the ambient temperature is determined to be stable; When the difference between the current tank water temperature and the previous tank water temperature is within a preset tank water temperature difference range, it is determined that the tank water temperature is stable.

6. The method according to claim 4, characterized in that Also includes: When the ratio of the current ambient temperature to the previous ambient temperature is within the preset ambient temperature ratio range, the ambient temperature is judged to be stable; when the ratio of the current tank water temperature to the previous tank water temperature is within the preset tank water temperature ratio range, the tank water temperature is judged to be stable.

7. The method according to claim 1, characterized in that: The step of determining the initial number of electronic expansion valve steps of the electronic expansion valve based on the ambient temperature and the water temperature of the water tank comprises: Determining the ambient temperature interval based on the ambient temperature, and determining the water tank water temperature interval based on the water tank water temperature; An initial electronic expansion valve step number of the electronic expansion valve is determined according to a preset corresponding relationship, wherein in the preset corresponding relationship, a group of ambient temperature intervals and water tank water temperature intervals correspond to one electronic expansion valve step number.

8. An electronic expansion valve control device for a heat pump water heater, characterized in that: include: The temperature parameter acquisition module is used to obtain the ambient temperature and the water temperature of the water tank when receiving the power-on command; An initial step number determination module, used to determine an initial electronic expansion valve step number of the electronic expansion valve based on the ambient temperature and the water temperature of the water tank; A normal operation control module, configured to adjust the electronic expansion valve according to a preset control scheme after the number of steps of controlling the electronic expansion valve is equal to the initial number of steps of the electronic expansion valve and the duration is equal to a first preset duration; An adjustment interval determination module is used to determine the adjustment interval duration of the electronic expansion valve based on the actual valve steps and the target valve steps of the electronic expansion valve when adjusting the electronic expansion valve according to a preset control scheme, and adjust the electronic expansion valve according to the adjustment interval duration.

9. A heat pump water heater electronic expansion valve control system, characterized in that: include: at least one processor and at least one memory; The memory stores executable instructions of the processor; The processor is configured to execute the method according to any one of claims 1 to 7.

10. A water heater, characterized in that: The method according to any one of claims 1 to 7 is used.

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