Control method for heat pump system, heat pump system, and storage medium

Abstract

The application discloses a kind of control method of heat pump system, heat pump system and storage medium.Therein, the heat pump system includes refrigerant main road and refrigerant branch connected with the refrigerant main road, the refrigerant main road includes indoor unit, outdoor unit and respectively with the compressor connected with indoor unit and outdoor unit, the refrigerant branch includes energy storage device, the method includes: control the heat pump system runs preset mode, obtains the pressure characteristic of the heat pump system;The energy storage device is in heat storage state in the preset mode, and the outdoor heat exchanger in the outdoor unit is in evaporation state;When the pressure characteristic is greater than first preset pressure characteristic, control the outdoor fan corresponding to the outdoor heat exchanger reduces operating speed.The present application aims at reducing the energy consumption of outdoor fan during the operation of heat pump system in the sole heat storage mode.

Description

Technical Field

[0001] This invention relates to the field of heat pump technology, and more particularly to a control method for a heat pump system, a heat pump system, and a storage medium. Background Technology

[0002] In addition to using energy to regulate the indoor environment, heat pump systems also include energy storage devices such as water tanks to provide energy for other needs. Typically, heat pump systems have a separate heat storage mode, in which indoor air conditioning is stopped, and heat is stored solely in the energy storage device.

[0003] However, in the standalone heat storage mode of a heat pump system, the speed of the outdoor fan is generally adjusted according to the outdoor ambient temperature. Since the outdoor ambient temperature is generally relatively stable during the operation of the heat pump system, the outdoor fan will maintain a fixed speed, which can easily lead to excessively high outdoor fan speed and energy waste. Summary of the Invention

[0004] The main objective of this invention is to provide a control method for a heat pump system, a heat pump system, and a storage medium, with the aim of reducing the energy consumption of the outdoor fan during the operation of the heat pump system in standalone heat storage mode.

[0005] To achieve the above objectives, the present invention provides a control method for a heat pump system. The heat pump system includes a refrigerant main circuit and refrigerant branch circuits connected to the refrigerant main circuit. The refrigerant main circuit includes an indoor unit, an outdoor unit, and compressors connected to the indoor unit and the outdoor unit respectively. The refrigerant branch circuits include an energy storage device. The control method for the heat pump system includes the following steps:

[0006] The heat pump system is controlled to operate in a preset mode, and the pressure characteristics representing the system pressure of the heat pump system are obtained; in the preset mode, the energy storage device is in a heat storage state, and the outdoor heat exchanger in the outdoor unit is in an evaporation state.

[0007] When the pressure characteristic is greater than the first preset pressure characteristic, the outdoor fan corresponding to the outdoor heat exchanger is controlled to reduce its operating speed.

[0008] Optionally, the step of controlling the outdoor fan corresponding to the outdoor heat exchanger to reduce its operating speed when the pressure characteristic is greater than the first preset pressure characteristic includes:

[0009] When the pressure characteristic is greater than the first preset pressure characteristic and the pressure characteristic is less than the second preset pressure characteristic, a first speed adjustment value is determined based on the pressure difference between the first preset pressure characteristic and the pressure characteristic, and the outdoor fan is controlled to reduce its operating speed based on the first speed adjustment value.

[0010] When the pressure characteristic is greater than or equal to the second preset pressure characteristic, and when the pressure characteristic is less than the third preset pressure characteristic, the outdoor fan speed is reduced according to a preset rate.

[0011] When the pressure characteristic is greater than or equal to the third preset pressure characteristic, the outdoor fan is controlled to reduce its speed to the minimum.

[0012] Wherein, the first preset pressure feature is less than the second preset pressure feature, and the second preset pressure feature is less than the third preset pressure feature.

[0013] Optionally, after the step of controlling the outdoor fan to reduce its operating speed to the minimum, the method further includes:

[0014] The outdoor fan is controlled to maintain the minimum speed until the current pressure characteristic of the heat pump system, which represents the current system pressure, is less than or equal to the fourth preset pressure characteristic. Then, the process returns to the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristic of the heat pump system.

[0015] The fourth preset pressure feature is smaller than the second preset pressure feature.

[0016] Optionally, after the step of obtaining the pressure characteristics of the heat pump system, the method further includes:

[0017] When the pressure characteristic is less than or equal to the target pressure characteristic of the heat pump system, the outdoor fan is controlled to increase its operating speed.

[0018] When the pressure characteristic is greater than the target pressure characteristic, and the pressure characteristic is less than or equal to the first preset pressure characteristic, the outdoor fan is controlled to maintain the current speed.

[0019] The target pressure feature is less than the first preset pressure feature.

[0020] Optionally, after the step of controlling the outdoor fan corresponding to the outdoor heat exchanger to reduce its operating speed when the pressure characteristic is greater than the first preset pressure characteristic, the method further includes:

[0021] When the current speed of the outdoor fan is greater than the preset speed, the process returns to the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristics of the heat pump system that represent the system pressure after a first time interval.

[0022] When the current speed of the outdoor fan is less than or equal to the preset speed, the process returns to the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristics of the heat pump system that characterize the system pressure after a second time interval.

[0023] Wherein, the first duration is longer than the second duration.

[0024] Optionally, the control method for the heat pump system further includes:

[0025] The heat pump system is controlled to start the preset mode to obtain the outdoor ambient temperature and the frequency characteristic value of the compressor.

[0026] The initial rotational speed of the outdoor fan is determined based on the outdoor ambient temperature and the frequency characteristic value.

[0027] When the outdoor fan is controlled to run at the initial speed until the first preset condition is met, the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristics of the heat pump system that characterize the system pressure is executed.

[0028] Optionally, the frequency characteristic value includes the ratio of the compressor's target frequency to the compressor's maximum frequency; and / or,

[0029] The first preset condition includes one of the following conditions:

[0030] The startup duration of the preset mode is greater than or equal to the first preset duration;

[0031] The startup duration of the preset mode is greater than or equal to the second preset duration, and the current pressure characteristic of the heat pump system, which represents the current system pressure, is greater than or equal to the fifth preset pressure characteristic, wherein the second preset duration is less than the first preset duration.

[0032] Optionally, the step of determining the initial rotational speed of the outdoor fan based on the outdoor ambient temperature and the frequency characteristic value includes:

[0033] When the outdoor ambient temperature is less than or equal to the preset ambient temperature, the maximum rotational speed is determined to be the initial rotational speed;

[0034] When the outdoor ambient temperature is greater than the preset ambient temperature, the initial rotational speed is determined within a rotational speed range less than the maximum rotational speed based on the outdoor ambient temperature and the frequency characteristic value.

[0035] Optionally, the heat pump system includes more than one indoor unit, and the control method of the heat pump system further includes:

[0036] The heat pump system is controlled to operate in a preset mode. When the number of indoor units that are turned on in more than one indoor unit changes, the initial speed of the outdoor fan and the energy demand parameters of the indoor units that currently have energy demand from the energy storage device are obtained. The initial speed is determined based on the outdoor ambient temperature and the frequency characteristic value of the compressor.

[0037] When the energy demand parameters and the initial speed meet the second preset condition, the outdoor fan is controlled to run at the initial speed.

[0038] When the energy demand parameter and the initial rotation speed do not meet the second preset condition, the step of obtaining the pressure characteristics of the heat pump system to characterize the system pressure is executed.

[0039] The second preset condition includes the increase in the energy demand parameter being greater than or equal to a preset value, and the initial rotational speed being greater than or equal to the current rotational speed of the outdoor fan.

[0040] Optionally, the steps for obtaining energy demand parameters include:

[0041] Obtain the total energy demand of all indoor units that currently require energy from the energy storage device and the capacity of the outdoor unit;

[0042] The energy demand parameter is determined based on the ratio of the total energy demand to the capacity.

[0043] In addition, to achieve the above objectives, this application also proposes a heat pump system, which includes a control device, a refrigerant main circuit and a refrigerant branch circuit connected to the refrigerant main circuit. The refrigerant main circuit includes an indoor unit, an outdoor unit and a compressor connected to the indoor unit and the outdoor unit respectively. The refrigerant branch circuit includes an energy storage device.

[0044] The compressor and the outdoor fan in the outdoor unit are connected to the control device, which includes a memory, a processor, and a control program for the heat pump system stored in the memory and executable on the processor. When the control program for the heat pump system is executed by the processor, it implements the steps of the control method for the heat pump system as described in any of the above claims.

[0045] In addition, to achieve the above objectives, this application also proposes a storage medium storing a control program for a heat pump system, which, when executed by a processor, implements the steps of the control method for the heat pump system as described in any of the preceding claims.

[0046] This invention proposes a control method for a heat pump system. Based on a heat pump system with a refrigerant branch equipped with an energy storage device, this method allows the outdoor fan to operate without adjusting according to the outdoor ambient temperature when the energy storage device is storing heat and the outdoor heat exchanger is evaporating. The pressure characteristic, which characterizes the system pressure of the heat pump system, can accurately reflect the condensation effect of the heat pump system. An excessively high pressure characteristic indicates that the outdoor heat exchanger has absorbed too much heat from the outdoor environment, exceeding the actual heat storage requirements of the energy storage device, and the outdoor fan speed is too high. At this time, the outdoor fan speed is reduced to decrease the heat absorbed by the outdoor heat exchanger from the outdoor environment, thereby meeting the actual heat storage requirements of the energy storage device and reducing the energy consumption of the outdoor fan. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the refrigerant system structure of an embodiment of the heat pump system of the present invention;

[0048] Figure 2 This is a schematic diagram of the hardware structure involved in the operation of an embodiment of the heat pump system of the present invention;

[0049] Figure 3 This is a flowchart illustrating an embodiment of the control method for the heat pump system of the present invention;

[0050] Figure 4 This is a schematic flowchart of another embodiment of the control method for the heat pump system of the present invention;

[0051] Figure 5 This is a flowchart illustrating another embodiment of the control method for the heat pump system of the present invention;

[0052] Figure 6 This is a flowchart illustrating another embodiment of the control method for the heat pump system of the present invention;

[0053] Figure 7 This is a schematic flowchart of another optional embodiment of the control method for the heat pump system of the present invention.

[0054] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0055] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0056] This invention provides a heat pump system.

[0057] In this embodiment of the invention, reference is made to Figure 1 and Figure 2 The heat pump system includes a control device 100, a refrigerant main circuit, and refrigerant branch circuits connected to the refrigerant main circuit. The refrigerant main circuit includes a compressor 1, an indoor unit, an outdoor heat exchanger 3, a throttling device 4, and a reversing assembly 5. The refrigerant branch circuits include an energy storage device 7 and a first control valve 8. The indoor unit, the reversing assembly 5, the compressor 1, the throttling device 4, and the first control valve 8 are all connected to the control device 100. The heat pump system also includes an outdoor unit, which includes an outdoor heat exchanger 3 and a corresponding outdoor fan. The compressor 1 can also be built into the outdoor unit.

[0058] In this embodiment, the energy storage device 7 includes a water tank, and external water-using equipment can be connected to the water tank to utilize the water containing energy stored in the energy storage device 7. In other embodiments, the energy storage device 7 may also include other types of devices with energy storage functions. When the refrigerant in the refrigerant branch flows through the energy storage device 7, it can exchange heat with the energy storage material therein, and the energy storage material can absorb and store the energy flowing through the refrigerant.

[0059] In one implementation of this embodiment, one end of the refrigerant branch is connected to the exhaust port of the compressor 1, and the pipeline between the indoor unit and the outdoor heat exchanger 3 is connected to the other end of the refrigerant branch.

[0060] In another implementation of this embodiment, the heat pump system may also be equipped with a flow direction regulating component. The pipeline between the indoor unit and the outdoor heat exchanger 3 is connected to the second end of the refrigerant branch. The return port of the compressor 1, the exhaust port of the compressor 1, and the first end of the refrigerant branch are all connected to the flow direction regulating component. The refrigerant branch switches between two states: being connected to the return port of the compressor 1 and being connected to the exhaust port of the compressor 1, through the flow direction regulating component. One end of the refrigerant branch is connected to the exhaust port of the compressor 1.

[0061] In this embodiment, there is more than one indoor unit, which can be connected in parallel. In other embodiments, there may be only one indoor unit.

[0062] The indoor unit includes an indoor heat exchanger 21 and a second control valve 22 connected in series with the indoor heat exchanger 21. The second control valve 22 is connected to a control device 100, which can be used to control the refrigerant flow through the indoor heat exchanger 21.

[0063] The indoor unit, throttling device 4, and outdoor heat exchanger 3 are connected in sequence. The pipe between the throttling device 4 and the indoor unit is connected to one end of the refrigerant branch. The exhaust port of the indoor unit, outdoor heat exchanger 3, and compressor 1, as well as the return port of compressor 1, are all connected to the reversing assembly 5. The reversing assembly 5 can be used to switch the connection status between the indoor unit and outdoor heat exchanger 3 and the exhaust port and return port of compressor 1.

[0064] In this embodiment, the reversing assembly 5 includes a first reversing valve 51 and a second reversing valve 52. The exhaust port of the compressor 1, the return port of the compressor 1, and the indoor unit are respectively connected to different valve ports of the first reversing valve 51, and the exhaust port of the compressor 1, the return port of the compressor 1, and the outdoor heat exchanger 3 are respectively connected to different valve ports of the second reversing valve 52. In one implementation of this embodiment, the first reversing valve 51 is a first four-way valve, and the second reversing valve 52 is a second four-way valve. In another implementation of this embodiment, the first reversing valve 51 is a first three-way valve, and the second reversing valve 52 is a second three-way valve.

[0065] The first reversing valve 51 has a first valve position and a second valve position. In the first valve position, the return port of the compressor 1 is connected to the indoor heat exchanger 21, and the exhaust port of the compressor 1 is blocked from the indoor heat exchanger 21. In the second valve position, the return port of the compressor 1 is blocked from the indoor heat exchanger 21, and the exhaust port of the compressor 1 is connected to the indoor heat exchanger 21.

[0066] The second reversing valve 52 has a third valve position and a fourth valve position. In the third valve position, the exhaust port of the compressor 1 is connected to the outdoor heat exchanger 3, and the return port of the compressor 1 is blocked from the outdoor heat exchanger 3. In the fourth valve position, the exhaust port of the compressor 1 is blocked from the outdoor heat exchanger 3, and the return port of the compressor 1 is connected to the outdoor heat exchanger 3.

[0067] In some embodiments, the reversing assembly 5 may further include a switching valve (not shown), which can be used to switch the connection state between the energy storage device 7 and the discharge port and return port of the compressor 1. The switching valve can be a three-way valve or a four-way valve, and the switching valve includes a first switching state and a second switching state; when the switching valve is in the first switching state, the return port of the compressor 1 is connected to the energy storage device 7; when the switching valve is in the second switching state, the discharge port of the compressor 1 is connected to the energy storage device 7.

[0068] Through the adjustment of the first reversing valve 51, the second reversing valve 52, the first control valve 8, and the second control valve 22, the operating modes of the heat pump system include, but are not limited to, the following modes:

[0069] In the first mode, refer to Figure 1 The first reversing valve 51 operates in the first valve position, the second reversing valve 52 operates in the fourth valve position, the second control valve 22 is closed, and the first control valve 8 is open. If the reversing assembly 5 includes a switching valve, the switching valve is in the second switching state. The exhaust port of the compressor 1 is connected to the energy storage device 7. All the refrigerant discharged by the compressor 1 flows into the refrigerant branch. The refrigerant flowing into the refrigerant branch stores heat in the energy storage device 7 as it flows through it. The refrigerant flowing out of the refrigerant branch flows through the throttling device 4 and the outdoor heat exchanger 3 in sequence before returning to the compressor 1. In the first mode, the indoor heat exchanger 21 stops exchanging heat, the outdoor heat exchanger 3 is in an evaporating state, and the energy storage device 7 is in a condensing state. All heat is used for heat storage in the energy storage device 7. In the first mode, the energy storage device 7 can store heat independently.

[0070] In the second mode, the first reversing valve 51 operates in the first valve position, the second reversing valve 52 operates in the third valve position, the first control valve 8 is open, and the second control valve 22 is open. If the reversing assembly 5 includes a switching valve, the switching valve is in the second switching state. The exhaust port of the compressor 1 is connected to the energy storage device 7. A portion of the refrigerant discharged by the compressor 1 flows sequentially through the outdoor heat exchanger 3 and the throttling device 4. Another portion of the refrigerant discharged by the compressor 1 flows into the refrigerant branch. The refrigerant flowing into the refrigerant branch stores heat in the energy storage device 7 as it flows through it. The refrigerant flowing out of the refrigerant branch merges with the refrigerant flowing out of the throttling device 4 and then flows into the indoor unit for evaporation before returning to the compressor 1. In the second mode, the indoor heat exchanger 21 is in the evaporation state, and the outdoor heat exchanger 3 is in the condensation state. In the second mode, when the indoor space regulated by the indoor unit has a heat exchange requirement, the indoor fan in the indoor unit can be turned on to drive the indoor air to exchange heat with the indoor heat exchanger 21; when the indoor space regulated by the indoor unit does not have a heat exchange requirement, the indoor fan in the indoor unit can be turned off. In the second mode, the heat absorbed by the outdoor heat exchanger 3 from its environment can be stored in the energy storage device 7. In the second mode, the energy storage device 7 can store heat during the cooling process of the indoor environment, or the oil in the compressor 1 in the refrigerant branch can be returned to the compressor 1 while the energy storage device 7 stores heat.

[0071] In the third mode, the first reversing valve 51 operates in the first valve position, the second reversing valve 52 operates in the fourth valve position, the first control valve 8 is open, and the second control valve 22 operates at a throttling rate. If the reversing assembly 5 includes a switching valve, the switching valve is in the second switching state. The exhaust port of the compressor 1 is connected to the energy storage device 7. All the refrigerant discharged by the compressor 1 flows into the refrigerant branch. The heat of the refrigerant flowing into the refrigerant branch is stored in the energy storage device 7 as it flows through the energy storage device 7. A portion of the refrigerant flowing out of the refrigerant branch flows through the throttling device 4 and the outdoor heat exchanger 3 in sequence before returning to the compressor 1. Another portion of the refrigerant flowing out of the refrigerant branch flows through the second control valve 22 and the indoor heat exchanger 21 in sequence before returning to the compressor 1. In the third mode, both the indoor heat exchanger 21 and the outdoor heat exchanger 3 are in an evaporating state. In the third mode, when the indoor space regulated by the indoor unit has a heat exchange requirement, the indoor fan in the indoor unit can be turned on to drive the indoor air to exchange heat with the indoor heat exchanger 21; when the indoor space regulated by the indoor unit does not have a heat exchange requirement, the indoor fan in the indoor unit can be turned off. In the third mode, the heat absorbed by the indoor heat exchanger 21 and the outdoor heat exchanger 3 from their respective environments can be stored in the energy storage device 7. In the third mode, the indoor environment can be cooled while the energy storage device 7 stores heat.

[0072] In the fourth mode, the first reversing valve 51 operates in the first valve position, the second reversing valve 52 operates in the third valve position, the first control valve 8 is closed, and the second control valve 22 is open. The refrigerant discharged from the compressor 1 flows sequentially through the outdoor heat exchanger 3, the throttling device 4, the second control valve 22, and the indoor heat exchanger 21 before returning to the compressor 1. In the fourth mode, the indoor heat exchanger 21 is in an evaporating state, and the outdoor heat exchanger 3 is in a condensing state. When the indoor space regulated by the indoor unit in the fourth mode has a heat exchange requirement, the indoor fan in the indoor unit can be turned on to drive the indoor air to exchange heat with the indoor heat exchanger 21; when the indoor space regulated by the indoor unit in the fourth mode does not have a heat exchange requirement, the indoor fan in the indoor unit can be turned off. In the fourth mode, the indoor environment can be cooled while the energy storage device 7 stops storing heat.

[0073] In other embodiments, the reversing assembly 5 may also include a third four-way valve, with the exhaust port of the compressor 1, the return port of the compressor 1, the indoor heat exchanger 21 and the outdoor heat exchanger 3 respectively connected to different ports of the third four-way valve.

[0074] Furthermore, refer to Figures 1 to 2 The heat pump system also includes a pressure characteristic sensor 03, which is connected to the control device 100. The pressure characteristic sensor 03 is used to detect the pressure characteristics of the heat pump system. In this embodiment, the pressure characteristic sensor 03 is located on the exhaust side of the compressor 1 to detect the high-pressure characteristics of the heat pump system. In this embodiment, the pressure characteristic sensor 03 is a temperature sensor used to detect the condensing temperature of the heat pump system (or condenser), which characterizes the condensing pressure of the system; alternatively, the pressure characteristic sensor 03 can also be used to detect the exhaust temperature of the compressor 1, and the control device 100 can determine the high-pressure characteristics based on the exhaust temperature. In other embodiments, the pressure characteristic sensor 03 can be a pressure sensor.

[0075] Furthermore, refer to Figure 2 The heat pump system also includes an environmental monitoring module 02, which is connected to the control device 100. The environmental monitoring module 02 can be located in the outdoor environment and is used to monitor the outdoor ambient temperature.

[0076] In this embodiment of the invention, reference is made to Figure 2 The control unit of the heat pump system includes a processor 1001, such as a CPU, a memory 1002, and a timer 1003. These components communicate with each other via a communication bus. The memory 1002 can be high-speed RAM or non-volatile memory, such as disk storage. Optionally, the memory 1002 can also be a storage device independent of the aforementioned processor 1001.

[0077] Those skilled in the art will understand that Figure 2The device structure shown does not constitute a limitation on the device and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0078] like Figure 2 As shown, the memory 1002, which serves as a computer storage medium, may include a control program for a heat pump system.

[0079] exist Figure 2 In the device shown, the processor 1001 can be used to call the control program of the heat pump system stored in the memory 1002 and execute the relevant steps of the control method of the heat pump system in the following embodiments.

[0080] This invention also provides a control method for a heat pump system, applied to the aforementioned heat pump system.

[0081] Reference Figure 3 This application proposes an embodiment of a control method for a heat pump system. In this embodiment, the control method for the heat pump system includes:

[0082] Step S10: Control the heat pump system to operate in a preset mode and obtain the pressure characteristics of the heat pump system that represent the system pressure; in the preset mode, the energy storage device is in a heat storage state and the outdoor heat exchanger in the outdoor unit is in an evaporation state.

[0083] In this embodiment, one end of the refrigerant branch is connected to the compressor's exhaust port, and the preset mode is the first mode mentioned above, which is the independent heat storage mode. The heat pump system can be put into the independent heat storage mode by adjusting the reversing component mentioned above.

[0084] In this embodiment, the pressure characteristics include high-pressure characteristics that characterize the high-pressure pressure of the system. In other embodiments, the pressure characteristics may also be original characteristics that characterize the low-pressure pressure of the heat pump system or the pressure at other locations, such as pressure characteristics that characterize the inlet pressure or outlet pressure of the energy storage device, the inlet pressure or outlet pressure of the outdoor heat exchanger, and so on.

[0085] The pressure characteristics can be detected by the detection module in the heat pump system, or determined based on the data detected by the detection module in the heat pump system. In this embodiment, the pressure characteristics include exhaust temperature or exhaust pressure or the saturation temperature corresponding to the exhaust pressure; the pressure characteristics can also be the condensation temperature.

[0086] During operation in the preset mode, data detected by the pressure characteristic sensor can be acquired in real time or at set intervals to obtain the pressure characteristics.

[0087] Step S20: When the pressure characteristic is greater than the first preset pressure characteristic, control the outdoor fan corresponding to the outdoor heat exchanger to reduce the operating speed.

[0088] The first preset pressure characteristic is specifically the minimum pressure characteristic reached when the outdoor heat exchanger of the pre-set heat pump system absorbs more ambient heat than the heat storage device requires in the preset mode.

[0089] When the pressure characteristic is greater than the first preset pressure characteristic, it indicates that the heat pump system absorbs more heat than the energy storage device needs in the preset mode. When the pressure characteristic is less than or equal to the first preset pressure characteristic, it indicates that the heat pump system absorbs less heat than the energy storage device needs in the preset mode.

[0090] During the process of reducing the operating speed of the outdoor fan: the outdoor fan speed is reduced according to a pre-set fixed speed adjustment value, or the outdoor fan speed is reduced according to the speed adjustment value determined by the actual operating status parameters of the heat pump system (e.g., the pressure difference between the first preset pressure characteristic and the pressure characteristic), or the outdoor fan speed is reduced according to a pre-set fixed speed, or the outdoor fan speed is controlled to be reduced to a pre-set target speed (e.g., minimum speed), etc.

[0091] Furthermore, after step S20, you can return to execute step S10.

[0092] This invention proposes a control method for a heat pump system. Based on a heat pump system with a refrigerant branch equipped with an energy storage device, this method allows the outdoor fan to operate without adjusting according to the outdoor ambient temperature when the energy storage device is storing heat and the outdoor heat exchanger is evaporating. The pressure characteristic representing the system pressure of the heat pump system can accurately reflect the condensation effect of the heat pump system. An excessively high pressure characteristic indicates that the outdoor heat exchanger has absorbed too much heat from the outdoor environment, exceeding the actual heat storage requirements of the energy storage device, and the outdoor fan speed is too high. At this time, the outdoor fan speed is reduced to decrease the heat absorbed by the outdoor heat exchanger from the outdoor environment, thereby meeting the actual heat storage requirements of the energy storage device and reducing the energy consumption of the outdoor fan.

[0093] Furthermore, based on the above embodiments, another embodiment of the control method for the heat pump system of this application is proposed. In this embodiment, reference is made to... Figure 4 Step S20 includes:

[0094] Step S21: When the pressure feature is greater than the first preset pressure feature and the pressure feature is less than the second preset pressure feature, a first speed adjustment value is determined based on the pressure difference between the first preset pressure feature and the pressure feature, and the outdoor fan is controlled to reduce its operating speed based on the first speed adjustment value.

[0095] Specifically, a correspondence between pressure difference and first speed adjustment value can be established in advance (e.g., calculation formula, mapping relationship, etc.), and the speed adjustment value corresponding to the current pressure difference can be determined based on this correspondence.

[0096] Furthermore, there are more than one pre-set correspondence between the pressure difference and the first speed adjustment value. The target correspondence can be determined based on the temperature change rate of the energy storage device and / or the temperature of the refrigerant heat dissipation module set between the first control valve and the throttling device. The first speed adjustment value corresponding to the pressure difference is determined based on the target correspondence.

[0097] The first speed adjustment value can be either the speed adjustment range or the speed adjustment coefficient. In this embodiment, the first speed adjustment value is the speed adjustment range. The sum of the current speed of the outdoor fan and the speed adjustment range is used as the target speed of the outdoor fan, and the outdoor fan is controlled to operate at the target speed.

[0098] When the pressure characteristic is greater than the first preset pressure characteristic and the pressure characteristic is less than the second preset pressure characteristic, the step of determining the first speed adjustment value based on the pressure difference between the first preset pressure characteristic and the pressure characteristic, and controlling the outdoor fan to reduce the operating speed based on the first speed adjustment value (step S21) is executed periodically, and the period can be 40 seconds.

[0099] Step S22: When the pressure characteristic is greater than or equal to the second preset pressure characteristic and the pressure characteristic is less than the third preset pressure characteristic, the outdoor fan is controlled to reduce its operating speed according to a preset rate.

[0100] The second preset pressure characteristic is a pre-set critical value that distinguishes the degree to which the outdoor heat exchanger absorbs more ambient heat than the energy storage device requires in a preset mode. The second preset pressure characteristic can be a fixed value or a value determined based on the actual operating conditions of the heat pump system (e.g., outdoor ambient temperature and / or the temperature of the energy storage device).

[0101] In this embodiment, the preset rate is a pre-set fixed rate. For example, the outdoor fan speed is reduced by 30% every 40 seconds.

[0102] When the pressure characteristic is greater than or equal to the second preset pressure characteristic, and the pressure characteristic is less than the third preset pressure characteristic, the step of controlling the outdoor fan to reduce its operating speed at a preset rate (step S22) is executed periodically, and the period can be 40 seconds.

[0103] In other embodiments, the preset rate can be determined from more than one preset fixed frequency based on the actual operating parameters of the heat pump system (e.g., outdoor ambient temperature and / or the temperature of the energy storage device).

[0104] Step S23: When the pressure characteristic is greater than or equal to the third preset pressure characteristic, control the outdoor fan to reduce its speed to the minimum; wherein, the first preset pressure characteristic is less than the second preset pressure characteristic, and the second preset pressure characteristic is less than the third preset pressure characteristic.

[0105] The third preset pressure characteristic is specifically a critical pressure characteristic value used to distinguish whether there is a reliability risk in the heat pump system. The second preset pressure characteristic can be a pre-set fixed value or a value determined based on the actual operating conditions of the heat pump system (e.g., outdoor ambient temperature and / or the temperature of the energy storage device and / or the compressor frequency, etc.).

[0106] When the pressure characteristic is greater than or equal to the third preset pressure characteristic, the step of controlling the outdoor fan to reduce its speed to the minimum (step S23) is executed immediately. In another embodiment, when the pressure characteristic is greater than or equal to the third preset pressure characteristic, the time for executing the step of controlling the outdoor fan to reduce its speed to the minimum (step S23) is less than a preset value, which is less than the execution cycle of steps S21 and S22.

[0107] It should be noted that the execution order of steps S21 to S23 is not specifically limited.

[0108] In this embodiment, when the pressure characteristic is greater than the first preset pressure characteristic but less than the second preset pressure characteristic, it indicates that the outdoor heat exchanger absorbs less ambient heat than the energy storage device requires. At this point, the outdoor fan speed is reduced by adjusting the speed according to the pressure difference. The outdoor fan can be finely adjusted intermittently to adapt to the pressure difference, ensuring that the outdoor fan speed adjustment reduces energy consumption while maintaining the energy storage efficiency of the energy storage device. When the pressure characteristic is greater than the first preset pressure characteristic, and greater than or equal to the second preset pressure characteristic but less than the third preset temperature, it indicates that the outdoor heat exchanger absorbs significantly more ambient heat than the energy storage device requires, but the heat pump system does not pose a risk of unreliable operation. At this point, the outdoor fan speed is reduced according to a preset rate, allowing the fan speed to decrease continuously. This helps to quickly reduce outdoor fan energy consumption while ensuring that the heat required by the energy storage device and the ambient heat absorbed by the outdoor heat exchanger can quickly reach a matching state, thus ensuring energy storage effectiveness while further reducing outdoor fan energy consumption. When the pressure characteristic is greater than or equal to the third preset pressure characteristic, it indicates that the heat pump system has a risk of unreliable operation. At this time, the outdoor fan is directly controlled to run at the lowest speed to minimize the amount of ambient heat absorbed by the outdoor heat exchanger, thereby rapidly reducing the system condensing pressure and improving the operational reliability of the heat pump system.

[0109] Furthermore, in this embodiment, after the step of controlling the outdoor fan to reduce its speed to the minimum, the method further includes: controlling the outdoor fan to maintain the minimum speed until the current pressure characteristic of the heat pump system is less than or equal to the fourth preset pressure characteristic, and returning to the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristic of the heat pump system; wherein the fourth preset pressure characteristic is less than the second preset pressure characteristic.

[0110] The fourth preset pressure characteristic is a critical pressure characteristic value used to distinguish whether the reliability risk of the heat pump system has been completely eliminated.

[0111] In this embodiment, the outdoor fan maintains its lowest speed until the pressure characteristics decrease sufficiently to effectively eliminate the risk of reliability issues. Then, the speed of the outdoor fan is readjusted to adapt to the pressure characteristics, thereby further reducing the energy consumption of the outdoor fan while improving the operational reliability of the heat pump system.

[0112] In other embodiments, the outdoor fan may be controlled to maintain the minimum speed for a preset time before returning to step S10.

[0113] Furthermore, based on any of the above embodiments, another embodiment of the control method for the heat pump system of this application is proposed. In this embodiment, reference is made to... Figure 5 After step S10, the method further includes:

[0114] Step S30: When the pressure characteristic is less than or equal to the target pressure characteristic of the heat pump system, control the outdoor fan to increase its operating speed;

[0115] The target pressure characteristic is the minimum pressure characteristic allowed when the heat pump system meets the heat storage requirements of the energy storage device.

[0116] In this embodiment, the target pressure characteristic can be determined based on the temperature of the energy storage device. Different energy storage temperatures correspond to different target pressure characteristics. In this embodiment, the energy storage temperature and the target pressure characteristic are positively correlated. A correspondence between energy storage temperature and target pressure characteristic is established in advance. This correspondence may include quantitative relationships, mapping relationships, etc., and the target pressure characteristic corresponding to the current energy storage temperature can be determined based on this correspondence.

[0117] During the process of increasing the operating speed of the outdoor fan: the outdoor fan speed is increased according to a pre-set fixed speed adjustment value, or the outdoor fan speed is increased according to the speed adjustment value determined by the actual operating status parameters of the heat pump system (such as the difference between the first preset pressure characteristic and the pressure characteristic), or the outdoor fan speed is increased according to a pre-set fixed speed, or the outdoor fan is controlled to increase to the pre-set target speed, etc.

[0118] Step S40: When the pressure characteristic is greater than the target pressure characteristic and the pressure characteristic is less than or equal to the first preset pressure characteristic, control the outdoor fan to maintain the current speed; wherein the target pressure characteristic is less than the first preset pressure characteristic.

[0119] Among them, the first preset pressure feature can be obtained by increasing the target pressure feature according to the preset value.

[0120] In this embodiment, when the pressure characteristic is less than or equal to the target pressure characteristic of the heat pump system, it indicates that the heat pump system is unable to meet the heat storage requirements of the energy storage device. At this time, the speed of the outdoor fan is increased in time to increase the heat absorbed by the outdoor heat exchanger, thereby ensuring that there is enough heat to meet the heat storage requirements of the energy storage device. When the pressure characteristic is greater than the target pressure characteristic but less than or equal to the first preset pressure characteristic, the outdoor fan is in a relatively energy-saving state while meeting the heat storage requirements of the energy storage device. At this time, the outdoor fan maintains the current speed, which is beneficial to improving the operational stability of the outdoor fan.

[0121] Furthermore, in this embodiment, after step S20, the following steps are also included:

[0122] When the current speed of the outdoor fan is greater than the preset speed, the process returns to the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristics of the heat pump system that represent the system pressure after a first time interval.

[0123] When the current speed of the outdoor fan is less than or equal to the preset speed, the process returns to the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristics of the heat pump system to represent the system pressure after a second time interval; wherein, the first time interval is longer than the second time interval.

[0124] The outdoor fan speed can be reduced to a minimum of 0. In this embodiment, the preset speed is 0. In other embodiments, the preset speed may also be other values ​​greater than 0.

[0125] The first and second durations can be preset fixed durations, such as a first duration of 40 seconds and a second duration of 20 seconds. Alternatively, the first and second durations can be determined based on the actual operating parameters of the heat pump system, such as the compressor's operating frequency and / or the energy storage temperature of the energy storage device.

[0126] In this embodiment, when the outdoor fan operates at very low speed or even stops, the outdoor fan is readjusted based on pressure characteristics at short intervals; when the outdoor fan operates at high speed, the outdoor fan is readjusted based on pressure characteristics at longer intervals. This helps to avoid the outdoor fan operating at low speed or being shut down for extended periods, which could affect the thermal storage efficiency of the energy storage device, thereby effectively improving the thermal storage performance of the energy storage device.

[0127] Furthermore, based on any of the above embodiments, another embodiment of the control method for the heat pump system of this application is proposed. In this embodiment, reference is made to... Figure 6 The control method for the heat pump system further includes:

[0128] Step S01: Control the heat pump system to start the preset mode and obtain the outdoor ambient temperature and the frequency characteristic value of the compressor;

[0129] In this embodiment, the frequency characteristic value includes the ratio of the target frequency of the compressor to the maximum frequency of the compressor. The target frequency can be determined based on the temperature difference between the temperature of the energy storage device and the set energy storage temperature, and the maximum frequency can be determined based on the outdoor ambient temperature.

[0130] In other embodiments, the frequency characteristic value may also include the actual operating frequency of the compressor.

[0131] Step S02: Determine the initial rotational speed of the outdoor fan based on the outdoor ambient temperature and the frequency characteristic value;

[0132] Different outdoor ambient temperatures and different frequency characteristic values ​​correspond to different initial rotational speeds. The correspondence between outdoor ambient temperature, frequency characteristic value, and initial rotational speed can be preset. This correspondence can include calculation formulas, mapping relationships, etc. Based on this correspondence, the initial rotational speed corresponding to the current outdoor ambient temperature and frequency characteristic value can be determined.

[0133] In this embodiment, when the outdoor ambient temperature is less than or equal to a preset ambient temperature (e.g., 20°C in the table below), the maximum rotational speed is determined as the initial rotational speed; when the outdoor ambient temperature is greater than the preset ambient temperature, the initial rotational speed is determined within a rotational speed range less than the maximum rotational speed based on the outdoor ambient temperature and the frequency characteristic value. Specifically, the initial rotational speed can be determined based on the temperature range of the outdoor ambient temperature and the numerical range of the frequency characteristic value.

[0134] For example, the correspondence between outdoor ambient temperature T4, frequency characteristic value n, and speed characteristic value X corresponding to the initial speed is shown in the table below:

[0135]

[0136] The table above shows the rotational speed characteristic value X corresponding to the current outdoor ambient temperature and frequency characteristic values. The initial rotational speed of the outdoor fan can then be calculated using the rotational speed characteristic value X.

[0137] In other embodiments, the initial rotational speed of the outdoor fan can also be calculated using the outdoor ambient temperature and frequency characteristic values.

[0138] Step S03: When the outdoor fan is controlled to run at the initial speed until the first preset condition is met, the step of obtaining the pressure characteristics of the heat pump system to characterize the system pressure is executed.

[0139] The first preset condition is specifically the condition that the operating parameters of the heat pump system must meet when the heat storage capacity of the energy storage device is greater than or equal to the preset heat capacity but the target heat capacity is not reached.

[0140] In this embodiment, the first preset condition includes one of the following conditions:

[0141] The startup duration of the preset mode is greater than or equal to the first preset duration;

[0142] The startup duration of the preset mode is greater than or equal to the second preset duration, and the current pressure characteristic of the heat pump system, which represents the current system pressure, is greater than or equal to the fifth preset pressure characteristic, wherein the second preset duration is less than the first preset duration.

[0143] The fifth preset pressure characteristic is specifically smaller than the third preset pressure characteristic mentioned above.

[0144] The first preset duration and the second preset duration are fixed values ​​that are preset. For example, the first preset duration is 2 minutes and the second preset duration is 20 seconds.

[0145] In this embodiment, during the startup phase of the preset mode, the initial speed of the outdoor fan is controlled according to the outdoor ambient temperature and the frequency characteristic value of the compressor. This helps ensure that the system can provide sufficient heat to rapidly raise the temperature of the energy storage device, thereby effectively improving the energy storage performance. Specifically, when the outdoor ambient temperature is low, the outdoor fan operates at its maximum speed, which helps the outdoor heat exchanger recover as much outdoor ambient heat as possible for use in the energy storage device, improving heat storage efficiency. When the outdoor ambient temperature is high, the initial speed of the outdoor fan is determined according to the outdoor ambient temperature and the frequency characteristic value of the compressor, which helps to meet the heat storage requirements while reducing energy consumption.

[0146] Furthermore, based on any of the above embodiments, another optional embodiment of the control method for the heat pump system of this application is proposed. In this embodiment, the heat pump system includes more than one indoor unit, referring to... Figure 7 The control method for the heat pump system further includes:

[0147] Step S50: Control the heat pump system to operate in a preset mode. When the number of indoor units that are turned on in more than one indoor unit changes, obtain the initial speed of the outdoor fan and the energy demand parameters of the indoor units that currently have energy demand from the energy storage device. The initial speed is determined based on the outdoor ambient temperature and the frequency characteristic value of the compressor.

[0148] The process for determining the initial rotational speed can be found in the above embodiments, and will not be repeated here.

[0149] When the number of indoor units turned on increases or decreases, the initial rotational speed and energy demand parameters can be obtained here.

[0150] The initial speed is determined based on the current outdoor ambient temperature and the current compressor frequency characteristic value.

[0151] Indoor units that require energy from energy storage devices refer to indoor units that regulate the indoor space to meet the energy needs of the energy storage devices, adapting to the actual needs of users. At the same time, there may be one or more indoor units that require energy from energy storage devices.

[0152] The energy demand parameter specifically refers to the state parameters that characterize the energy storage device's demand on the compressor's output capacity in a preset mode when the indoor unit has a capacity requirement for the energy storage device. The energy demand parameter can be determined based on the detection data inside the energy storage device and / or the detection data of the environment where the heat pump system is located and / or the number of indoor units that have an energy demand for the energy storage device and / or the compressor's operating parameters, etc.

[0153] Step S60: When the energy demand parameter and the initial rotation speed meet the second preset condition, control the outdoor fan to operate at the initial rotation speed; the second preset condition includes the increase in the energy demand parameter being greater than or equal to a preset value, and the initial rotation speed being greater than or equal to the current rotation speed of the outdoor fan;

[0154] Step S70: When the energy demand parameter and the initial rotation speed do not meet the second preset condition, the step of obtaining the pressure characteristics of the heat pump system to characterize the system pressure is executed; the second preset condition includes the increase of the energy demand parameter being greater than or equal to a preset value, and the initial rotation speed being greater than or equal to the current rotation speed of the outdoor fan.

[0155] The second preset condition includes the increase in the energy demand parameter being greater than or equal to a preset value, and the initial rotational speed being greater than or equal to the current rotational speed of the outdoor fan.

[0156] It should be noted that during the execution of steps S10 and S20, before step S10 or after step S20, the number of indoor units turned on can be detected in real time to see if it changes. When it changes, the control method of the outdoor fan is determined by adapting to the initial speed and energy demand parameters.

[0157] In this embodiment, when the number of indoor units activated changes, if the energy demand increases significantly and the initial rotational speed is higher than the current rotational speed of the outdoor fan, a higher initial rotational speed is used to control the outdoor fan's operation. This ensures that the energy storage device's energy can accurately meet the needs of the newly added indoor units. When the number of indoor units activated changes, if the energy demand increases only slightly, decreases, or the initial rotational speed is lower than the current rotational speed of the outdoor fan, the outdoor fan's rotational speed is determined according to the pressure characteristics as described in the above embodiment. This helps to meet the indoor energy storage device's usage needs while reducing energy consumption.

[0158] Furthermore, in this embodiment, the step of obtaining the energy demand parameter includes: obtaining the total energy demand value of all indoor units that currently have energy demand for the energy storage device and the capacity of the outdoor unit; and determining the energy demand parameter based on the ratio of the total energy demand value to the capacity.

[0159] In this embodiment, the capacity here refers to the rated capacity. In other embodiments, the capacity may be determined based on the operating frequency of the outdoor unit.

[0160] Obtain the actual energy demand of the energy storage device under the current operating conditions and the rated energy demand of the energy storage device; determine the total energy demand based on the actual energy demand and the rated energy demand.

[0161] Actual energy demand is related to the actual operating conditions of the energy storage device and can vary with changes in actual operating conditions. Rated energy demand is related to the inherent properties of the energy storage device and does not change with changes in actual operating conditions.

[0162] In this embodiment, the sum of the actual energy demand and the rated energy demand is determined as the total energy demand. In other embodiments, the rated energy demand can be used to determine a correction factor, and the actual energy demand can be corrected according to the correction factor to obtain the total energy demand.

[0163] The process of obtaining the actual energy demand is as follows: obtain the energy storage temperature of the energy storage device and the outdoor ambient temperature corresponding to the heat pump system; determine the actual energy demand based on the energy storage temperature and the outdoor ambient temperature.

[0164] The energy storage temperature is detected by the aforementioned temperature sensor. The outdoor ambient temperature is detected by the aforementioned environmental monitoring module.

[0165] Different energy storage temperatures and different outdoor ambient temperatures correspond to different actual energy demands. Actual energy demand is negatively correlated with outdoor ambient temperature, and also negatively correlated with energy storage temperature.

[0166] Specifically, a correspondence between energy storage temperature, outdoor ambient temperature and actual energy demand can be established in advance. This correspondence can include calculation formulas, mapping relationships, etc. Based on this correspondence, the actual energy demand corresponding to the current energy storage temperature and outdoor ambient temperature can be determined.

[0167] Furthermore, there can be more than one pre-set correspondence between energy storage temperature, outdoor ambient temperature and actual energy demand. The target correspondence can be determined from the more than one correspondence based on the operating speed of the outdoor fan corresponding to the outdoor heat exchanger and the temperature difference between the energy storage temperature and the target temperature. Based on the target correspondence, the actual energy demand corresponding to the current energy storage temperature and outdoor ambient temperature can be determined.

[0168] Here, combining the outdoor ambient temperature and the energy storage temperature can accurately reflect the operating conditions of the preset mode. Therefore, adapting the outdoor ambient temperature and the energy storage temperature to determine the actual energy demand value is beneficial to ensuring that the actual energy demand value can accurately reflect the actual energy demand of the energy storage device under the current operating conditions. This is conducive to further improving the accuracy of compressor frequency operation control and improving the energy storage efficiency of the energy storage device.

[0169] In other implementation methods, the actual energy demand can be determined based on either the outdoor ambient temperature or the energy storage temperature, or based on other parameters besides the outdoor ambient temperature and the energy storage temperature. These other parameters could be, for example, the temperature difference between the energy storage temperature and the set temperature of the energy storage device, and / or the temperature change rate of the outdoor heat exchanger, and / or the temperature difference between the inner and outer surface temperatures of the energy storage device, and / or the temperature change rate between the inner and outer surface temperatures of the energy storage device, etc.

[0170] In other implementation methods, either the actual energy requirement or the rated energy requirement can be used as the total energy requirement.

[0171] In this embodiment, the energy demand parameter is determined based on the ratio of the total energy demand to the capacity. This helps to accurately reflect the degree of matching between the compressor's output capacity and the demand when the indoor unit has a demand for the energy storage device. Therefore, the outdoor fan is regulated based on the energy demand parameter determined in this way and the initial speed. This helps to further meet the indoor demand for the energy storage device while reducing the energy consumption of the outdoor fan and improving the operational stability of the heat pump system.

[0172] Furthermore, embodiments of the present invention also propose a storage medium storing a control program for a heat pump system. When the control program for the heat pump system is executed by a processor, it implements the relevant steps of any embodiment of the control method for the heat pump system described above.

[0173] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0174] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0175] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, heat pump system, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0176] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A control method for a heat pump system, characterized in that, The heat pump system includes a refrigerant main circuit and refrigerant branch circuits connected to the refrigerant main circuit. The refrigerant main circuit includes an indoor unit, an outdoor unit, and compressors connected to the indoor unit and the outdoor unit respectively. The refrigerant branch circuits include an energy storage device. The control method of the heat pump system includes the following steps: The heat pump system is controlled to operate in a preset mode, and the pressure characteristics representing the system pressure of the heat pump system are obtained; in the preset mode, the energy storage device is in a heat storage state, and the outdoor heat exchanger in the outdoor unit is in an evaporation state. When the pressure characteristic is greater than the first preset pressure characteristic, the outdoor fan corresponding to the outdoor heat exchanger is controlled to reduce its operating speed. The step of controlling the outdoor fan corresponding to the outdoor heat exchanger to reduce its operating speed when the pressure characteristic is greater than the first preset pressure characteristic includes: When the pressure characteristic is greater than the first preset pressure characteristic and the pressure characteristic is less than the second preset pressure characteristic, a first speed adjustment value is determined based on the pressure difference between the first preset pressure characteristic and the pressure characteristic, and the outdoor fan is controlled to reduce its operating speed based on the first speed adjustment value. When the pressure characteristic is greater than or equal to the second preset pressure characteristic, and when the pressure characteristic is less than the third preset pressure characteristic, the outdoor fan speed is reduced according to a preset rate. When the pressure characteristic is greater than or equal to the third preset pressure characteristic, the outdoor fan is controlled to reduce its speed to the minimum. Wherein, the first preset pressure feature is less than the second preset pressure feature, and the second preset pressure feature is less than the third preset pressure feature.

2. The control method for a heat pump system as described in claim 1, characterized in that, After the step of controlling the outdoor fan to reduce its speed to the minimum, the method further includes: The outdoor fan is controlled to maintain the minimum speed until the current pressure characteristic of the heat pump system, which represents the current system pressure, is less than or equal to the fourth preset pressure characteristic. Then, the process returns to the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristic of the heat pump system, which represents the current system pressure. The fourth preset pressure feature is smaller than the second preset pressure feature.

3. The control method for a heat pump system as described in claim 1, characterized in that, After the step of obtaining the pressure characteristics of the heat pump system, the method further includes: When the pressure characteristic is less than or equal to the target pressure characteristic of the heat pump system, the outdoor fan is controlled to increase its operating speed. When the pressure characteristic is greater than the target pressure characteristic, and the pressure characteristic is less than or equal to the first preset pressure characteristic, the outdoor fan is controlled to maintain the current speed. The target pressure feature is less than the first preset pressure feature.

4. The control method for a heat pump system as described in claim 1, characterized in that, After the step of controlling the outdoor fan corresponding to the outdoor heat exchanger to reduce its operating speed when the pressure characteristic is greater than the first preset pressure characteristic, the method further includes: When the current speed of the outdoor fan is greater than the preset speed, the process returns to the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristics of the heat pump system that represent the system pressure after a first time interval. When the current speed of the outdoor fan is less than or equal to the preset speed, the process returns to the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristics of the heat pump system that characterize the system pressure after a second time interval. Wherein, the first duration is longer than the second duration.

5. The control method for a heat pump system as described in claim 1, characterized in that, The control method for the heat pump system also includes: The heat pump system is controlled to start the preset mode to obtain the outdoor ambient temperature and the frequency characteristic value of the compressor. The initial rotational speed of the outdoor fan is determined based on the outdoor ambient temperature and the frequency characteristic value. When the outdoor fan is controlled to run at the initial speed until the first preset condition is met, the step of controlling the heat pump system to operate in the preset mode and obtaining the pressure characteristics of the heat pump system that characterize the system pressure is executed.

6. The control method for a heat pump system as described in claim 5, characterized in that, The frequency characteristic value includes the ratio of the compressor's target frequency to the compressor's maximum frequency; and / or, The first preset condition includes one of the following conditions: The startup duration of the preset mode is greater than or equal to the first preset duration; The startup duration of the preset mode is greater than or equal to the second preset duration, and the current pressure characteristic of the heat pump system, which represents the current system pressure, is greater than or equal to the fifth preset pressure characteristic, wherein the second preset duration is less than the first preset duration.

7. The control method for a heat pump system as described in claim 5, characterized in that, The step of determining the initial rotational speed of the outdoor fan based on the outdoor ambient temperature and the frequency characteristic value includes: When the outdoor ambient temperature is less than or equal to the preset ambient temperature, the maximum rotational speed is determined to be the initial rotational speed; When the outdoor ambient temperature is greater than the preset ambient temperature, the initial rotational speed is determined within a rotational speed range less than the maximum rotational speed based on the outdoor ambient temperature and the frequency characteristic value.

8. The control method for a heat pump system as described in claim 1, characterized in that, The heat pump system includes more than one indoor unit, and the control method for the heat pump system further includes: The heat pump system is controlled to operate in a preset mode. When the number of indoor units that are turned on in more than one indoor unit changes, the initial speed of the outdoor fan and the energy demand parameters of the indoor units that currently have energy demand from the energy storage device are obtained. The initial speed is determined based on the outdoor ambient temperature and the frequency characteristic value of the compressor. When the energy demand parameters and the initial speed meet the second preset condition, the outdoor fan is controlled to run at the initial speed. When the energy demand parameter and the initial rotation speed do not meet the second preset condition, the step of obtaining the pressure characteristics of the heat pump system to characterize the system pressure is executed. The second preset condition includes the increase in the energy demand parameter being greater than or equal to a preset value, and the initial rotational speed being greater than or equal to the current rotational speed of the outdoor fan.

9. The control method for a heat pump system as described in claim 8, characterized in that, The steps to obtain energy demand parameters include: Obtain the total energy demand of all indoor units that currently require energy from the energy storage device and the capacity of the outdoor unit; The energy demand parameter is determined based on the ratio of the total energy demand to the capacity.

10. A heat pump system, characterized in that, The heat pump system includes a control device, a refrigerant main circuit, and refrigerant branch circuits connected to the refrigerant main circuit. The refrigerant main circuit includes an indoor unit, an outdoor unit, and compressors connected to the indoor unit and the outdoor unit respectively. The refrigerant branch circuits include an energy storage device. The compressor and the outdoor fan in the outdoor unit are connected to the control device, which includes a memory, a processor, and a control program for the heat pump system stored in the memory and executable on the processor. When the control program for the heat pump system is executed by the processor, it implements the steps of the control method for the heat pump system as described in any one of claims 1 to 9.

11. A storage medium, characterized in that, The storage medium stores a control program for a heat pump system, which, when executed by a processor, implements the steps of the control method for a heat pump system as described in any one of claims 1 to 9.

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