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

Abstract

The invention discloses a control method of a heat pump system, the heat pump system and a storage medium. The heat pump system comprises a refrigerant main path, a refrigerant branch path and a switching assembly, the refrigerant branch path comprises an energy storage device, a pipeline between a throttling device and an indoor unit is connected with the first end of the refrigerant branch path, and the second end of the refrigerant branch path, an exhaust port of a compressor and an air return port of the compressor are all connected with the switching assembly. The method comprises the steps that the reversing assembly is controlled to operate in a first state so that the indoor unit can communicate with the exhaust port, the outdoor heat exchanger can communicate with the air return port, and the switching assembly is controlled to operate in a third state so that the second end of the refrigerant branch can communicate with the exhaust port. And when the operation of the heat pump system reaches the defrosting starting condition, the reversing assembly is controlled to operate in a second state so that the outdoor heat exchanger can communicate with the exhaust port, and the switching assembly is controlled to operate in a fourth state so that the second end of the refrigerant branch can communicate with the air return port. The invention aims to improve the indoor comfort and defrosting efficiency during defrosting operation of the heat pump system.

Description

Technical Field

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

[0002] In addition to providing energy for indoor environmental regulation, the heat pump system can also be equipped with energy storage devices to meet other temperature regulation needs. When the heat pump system is in heating operation, the indoor heat exchanger is in a condensing state and the outdoor heat exchanger is in an evaporating state. When the outdoor ambient temperature is low, the outdoor heat exchanger will frost and the heat pump system needs to switch to defrosting operation.

[0003] However, when the heat pump system is currently defrosting, the outdoor heat exchanger is in a condensing state and the indoor heat exchanger needs to be switched to an evaporating state to absorb heat. However, this can easily cause indoor temperature fluctuations and affect indoor comfort during the defrosting process. Summary of the invention

[0004] The main purpose of the present invention is to provide a control method for a heat pump system, a heat pump system and a storage medium, aiming to improve indoor comfort and defrosting efficiency during defrosting operation of the heat pump system.

[0005] To achieve the above-mentioned object, the present invention provides a control method for a heat pump system, the heat pump system comprising a refrigerant main circuit, a refrigerant branch circuit and a switching component, the refrigerant main circuit comprising an indoor unit, a throttling device, an outdoor heat exchanger, a reversing component and a compressor, the indoor unit, the throttling device and the outdoor heat exchanger are connected in sequence, the refrigerant branch circuit comprises an energy storage device, a pipeline between the throttling device and the indoor unit is connected to a first end of the refrigerant branch circuit, a second end of the refrigerant branch circuit, an exhaust port of the compressor and an air return port of the compressor are all connected to the switching component, and the control method for the heat pump system comprises the following steps:

[0006] Control the reversing component to operate in a first state so that the indoor unit is connected to the exhaust port and the outdoor heat exchanger is connected to the return air port, and control the switching component to operate in a third state so that the second end of the refrigerant branch is connected to the exhaust port;

[0007] When the heat pump system reaches the defrost start condition, the reversing component is controlled to operate in the second state to connect the outdoor heat exchanger with the exhaust port, and the switching component is controlled to operate in the fourth state to connect the second end of the refrigerant branch with the return air port.

[0008] Optionally, the process of controlling the reversing component to operate in the second state so that the outdoor heat exchanger is connected to the exhaust port, and controlling the switching component to operate in the fourth state so that the second end of the refrigerant branch is connected to the return air port, further includes:

[0009] The operation of the compressor is controlled according to the energy demand parameter of the energy storage device and / or the pressure characteristic of the heat pump system representing the system pressure.

[0010] Optionally, the step of controlling the operation of the compressor according to the pressure characteristic representing the system pressure of the heat pump system comprises:

[0011] When the pressure characteristic is less than or equal to a preset pressure characteristic, controlling the operation of the compressor according to the pressure characteristic and a target pressure characteristic;

[0012] When the pressure characteristic is greater than the preset pressure characteristic, the compressor is restricted from operating at an increased frequency, or the compressor is controlled to operate at a reduced frequency, or the compressor is controlled to stop.

[0013] Optionally, the step of controlling the operation of the compressor according to the pressure characteristic and the target pressure characteristic includes:

[0014] determining a pressure characteristic difference between the pressure characteristic and the target pressure characteristic;

[0015] When the pressure characteristic difference is greater than a first preset threshold, controlling the compressor to operate at a reduced frequency;

[0016] When the pressure characteristic difference is less than or equal to a second preset threshold, controlling the compressor to increase the frequency of operation;

[0017] The second preset threshold is less than or equal to the first preset threshold.

[0018] Optionally, the step of limiting the compressor to increase frequency or controlling the compressor to decrease frequency or controlling the compressor to stop includes:

[0019] When the pressure characteristic is less than or equal to a first pressure characteristic threshold, executing the step of limiting the compressor up-frequency operation;

[0020] When the pressure characteristic is greater than the first pressure characteristic threshold and less than or equal to the second pressure characteristic threshold, executing the step of controlling the compressor to operate at reduced frequency;

[0021] When the pressure characteristic is greater than the second pressure characteristic threshold, executing the step of stopping the compressor;

[0022] Among them, the first pressure characteristic threshold is greater than the preset pressure characteristic, and the second pressure characteristic threshold is greater than the first pressure characteristic threshold.

[0023] Optionally, the step of limiting the compressor from running at an increased frequency comprises:

[0024] When the pressure characteristic is less than or equal to a third pressure characteristic threshold, controlling the compressor to increase frequency and operate at a rate less than a preset rate;

[0025] When the pressure characteristic is greater than the third pressure characteristic threshold and the pressure characteristic is less than or equal to the first pressure characteristic threshold, controlling the compressor to maintain the current frequency operation;

[0026] Among them, the third pressure characteristic threshold is greater than the preset pressure characteristic, and the third pressure characteristic threshold is less than the first pressure characteristic threshold.

[0027] Optionally, the step of controlling the compressor to operate at reduced frequency includes:

[0028] determining a frequency adjustment value according to the pressure characteristic;

[0029] controlling the compressor to reduce the current operating frequency according to the frequency adjustment value;

[0030] Wherein, the frequency adjustment value is positively correlated with the pressure characteristic.

[0031] Optionally, the step of controlling the operation of the compressor according to the energy demand parameter of the energy storage device includes:

[0032] Correcting the energy demand parameter according to the target correction value to obtain the target frequency of the compressor;

[0033] controlling the compressor to operate at the target frequency;

[0034] Wherein, the target correction value is determined according to the exhaust parameter of the compressor.

[0035] Optionally, before the step of controlling the operation of the compressor according to the energy demand parameter of the energy storage device and / or the pressure characteristic of the heat pump system characterizing the system pressure, the step further includes:

[0036] In the process of the reversing component operating in the second state and the switching component operating in the fourth state, obtaining an actual energy requirement value of the energy storage device under the current working condition and a rated energy requirement value of the energy storage device;

[0037] The energy demand parameter is determined according to the actual energy demand value and the rated energy demand value.

[0038] Optionally, the step of obtaining the actual energy requirement value of the energy storage device under the current working condition includes:

[0039] Acquire the energy storage temperature of the energy storage device and the outdoor ambient temperature corresponding to the heat pump system;

[0040] The actual energy requirement value is determined according to the energy storage temperature and the outdoor ambient temperature.

[0041] Optionally, the step of obtaining the rated energy requirement value of the energy storage device includes:

[0042] Obtaining the volume of the energy storage device for storing energy storage material;

[0043] The rated energy demand is determined based on the volume.

[0044] Optionally, the step of controlling the operation of the compressor according to the energy demand parameter of the energy storage device and / or the pressure characteristic of the heat pump system characterizing the system pressure includes:

[0045] Controlling the operation of the compressor according to the energy demand parameter;

[0046] When the operation of the heat pump system reaches a preset condition, the operation of the compressor is controlled according to the pressure characteristic.

[0047] Optionally, the preset condition includes at least one of the following conditions:

[0048] The operation time of the reversing component operating in the second state and the switching component operating in the fourth state is greater than a preset time;

[0049] The pressure characteristic of the heat pump system currently representing the system pressure is greater than a fourth pressure characteristic threshold.

[0050] Optionally, the control method of the heat pump system further includes:

[0051] When the reversing component operates in the second state and the switching component operates in the fourth state, the control valve in the indoor unit is controlled to be closed.

[0052] In addition, in order to achieve the above-mentioned purpose, the present application also proposes a heat pump system, which includes: a memory, a processor, and a control program of the heat pump system stored in the memory and executable on the processor, and when the control program of the heat pump system is executed by the processor, the steps of the control method of the heat pump system as described in any of the above items are implemented.

[0053] In addition, in order to achieve the above-mentioned purpose, the present application also proposes a storage medium, on which a control program of a heat pump system is stored. When the control program of the heat pump system is executed by a processor, the steps of the control method of the heat pump system as described in any of the above items are implemented.

[0054] The present invention proposes a control method for a heat pump system, wherein the heat pump system heats the indoor room while an energy storage device stores heat through the operation coordination of the first operating state of the reversing component and the third state of the switching component. When the operation reaches the defrost start condition, the exhaust heat of the compressor is used to melt the frost by the outdoor heat exchanger through the operation coordination of the second state of the reversing component and the fourth state of the switching component. At the same time, the throttled refrigerant after heat exchange in the outdoor heat exchanger can flow through the energy storage device to absorb heat and then flow back to the compressor. During the defrost process, the amount of low-temperature refrigerant flowing into the indoor unit can be effectively reduced, which can effectively reduce indoor temperature fluctuations, and a large amount of heat can be absorbed from the energy storage device, which can effectively improve the defrost efficiency of the outdoor heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A schematic diagram of the refrigerant pipeline structure of an embodiment of a heat pump system of the present invention and a schematic diagram of the refrigerant flow direction in a first mode;

[0056] Figure 2 A schematic diagram of the refrigerant pipeline structure of an embodiment of a heat pump system of the present invention and a schematic diagram of the refrigerant flow direction in the second mode;

[0057] Figure 3 A schematic diagram of the refrigerant pipeline structure of an embodiment of a heat pump system of the present invention and a schematic diagram of the refrigerant flow direction in a third mode;

[0058] Figure 4 A schematic diagram of the hardware structure involved in the operation of an embodiment of a heat pump system of the present invention;

[0059] Figure 5 A schematic flow chart of an embodiment of a control method for a heat pump system of the present invention;

[0060] Figure 6 A schematic flow chart of another embodiment of a control method for a heat pump system of the present invention;

[0061] Figure 7 A schematic flow chart of another embodiment of a control method for a heat pump system of the present invention;

[0062] Figure 8 This is a flow chart of another embodiment of a control method for a heat pump system of the present invention.

[0063] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0064] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0065] An embodiment of the present invention provides a heat pump system.

[0066] In the embodiment of the present invention, refer to Figures 1 to 4 The heat pump system includes a control device 100, a refrigerant main circuit, a refrigerant branch circuit and a switching component 9. The refrigerant main circuit includes a compressor 1, an indoor unit, an outdoor heat exchanger 3, a throttling device 4 and a reversing component 5. The indoor unit, the outdoor heat exchanger 3 and the throttling device 4 are connected in sequence. The refrigerant branch circuit includes an energy storage device 7 and a first control valve 8. The indoor unit, the reversing component 5, the compressor 1, the throttling device 4, the first control valve 8 and the switching component 9 are all connected to the control device 100. Among them, the heat pump system also includes an outdoor unit, and the outdoor unit includes the above-mentioned outdoor heat exchanger 3, the throttling device 4, the reversing component 5 and the first control valve 8. The throttling device 4 and the first control valve 8 can be electronic expansion valves.

[0067] In this embodiment, the energy storage device 7 includes a water tank. 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.

[0068] The pipeline between the indoor unit and the outdoor heat exchanger 3 is connected to the first end of the refrigerant branch, and the return air port of the compressor 1, the exhaust port of the compressor 1 and the second end of the refrigerant branch are all connected to the switching component 9. The refrigerant branch is switched between the two states of being connected to the return air port of the compressor 1 and being connected to the exhaust port of the compressor 1 through the switching component 9. When the second end of the refrigerant branch is connected to the exhaust port of the compressor 1, the energy storage device 7 is in a heat storage state; when the second end of the refrigerant branch is connected to the return air port of the compressor 1, the energy storage device 7 is in a cold storage state.

[0069] In this embodiment, the number of indoor units is more than one, and more than one indoor units can be connected in parallel, and different indoor units are arranged in different indoor spaces to adjust the indoor environment of different indoor spaces. In other embodiments, the number of indoor units can also be one.

[0070] 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 the control device 100. The second control valve 22 may be an electronic expansion valve. The control device 100 may be used to control the opening of the second control valve 22 to adjust the flow of the refrigerant flowing through the indoor heat exchanger 21. An indoor fan is provided corresponding to the indoor heat exchanger 21. When the indoor fan is turned on, the air in the corresponding indoor environment is driven to exchange heat with the indoor heat exchanger 21; when the indoor fan is turned off, the air in the corresponding indoor environment stops exchanging heat with the indoor heat exchanger 21.

[0071] The indoor unit, the outdoor heat exchanger 3, the exhaust port of the compressor 1 and the return air port of the compressor 1 are all connected to the reversing assembly 5. The reversing assembly 5 can be used to switch the connection state between the indoor unit and the outdoor heat exchanger 3 and the exhaust port of the compressor 1 and the return air port of the compressor 1.

[0072] 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 air 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 air 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.

[0073] The first reversing valve 51 has a first valve position and a second valve position. In the first valve position, the return air 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 air 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.

[0074] 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 air 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 air port of the compressor 1 is connected to the outdoor heat exchanger 3.

[0075] In this embodiment, the switching component 9 is a three-way valve. In other embodiments, the switching component 9 may also be a four-way valve or a combination of more than one one-way valves, etc. The switching component 9 has a fifth valve position and a sixth valve position. In the fifth valve position, the exhaust port of the compressor 1 is connected to the second end of the refrigerant branch; in the sixth valve position, the return port of the compressor 1 is connected to the second end of the refrigerant branch.

[0076] Through the regulation of the first reversing valve 51, the second reversing valve 52, the first control valve 8 and the second control valve 22, the operation modes of the heat pump system include but are not limited to the following modes:

[0077] In the first mode, refer to Figure 1, the first reversing valve 51 operates at the second valve position, the second reversing valve 52 operates at the fourth valve position, the switching assembly 9 operates at the fifth valve position, the first control valve 8 is opened, the second control valve 22 is opened, a part of the refrigerant discharged from the compressor 1 flows through the indoor heat exchanger 21, the second control valve 22, the throttling device 4 and the outdoor heat exchanger 3 in sequence, and then flows back to the compressor 1; another part of the refrigerant discharged from the compressor 1 flows into the refrigerant branch, and the heat is stored in the energy storage device 7 when the refrigerant flows through the energy storage device 7. The refrigerant flowing out of the refrigerant branch merges with the refrigerant flowing out of the indoor unit and flows through the throttling device 4 and the outdoor heat exchanger 3 in sequence, and then flows back to the compressor 1. In the first mode, the indoor heat exchanger 21 is in a condensing state, and the outdoor heat exchanger 3 is in an evaporating state. In the first mode, the indoor environment can be heated while the energy storage device 7 stores heat.

[0078] In the second mode, refer to Figure 2 , the first reversing valve 51 operates at the first valve position, the second reversing valve 52 operates at the third valve position, the switching assembly 9 operates at the fifth valve position, the first control valve 8 is closed, the second control valve 22 is opened, and the refrigerant discharged from the compressor 1 flows through the outdoor heat exchanger 3, the throttling device 4, the second control valve 22, and the indoor heat exchanger 21 in sequence and then flows back to the compressor 1. In the second mode, the indoor heat exchanger 21 is in an evaporating state and the outdoor heat exchanger 3 is in a condensing state. In the second mode, the indoor environment can be cooled or the outdoor heat exchanger 3 can be defrosted.

[0079] In the third mode, refer to Figure 3 , the first reversing valve 51 operates at the second valve position, the second reversing valve 52 operates at the third valve position, the switching assembly 9 operates at the sixth valve position, the first control valve 8 is opened, the second control valve 22 is opened or closed, and the refrigerant discharged from the compressor 1 flows through the outdoor heat exchanger 3 and the throttling device 4 in sequence, and then partially or completely flows into the refrigerant branch. When the refrigerant flows through the energy storage device 7, it absorbs the energy in the energy storage device 7 and then flows back to the compressor 1. When the second control valve 22 is opened, part of the refrigerant flowing out of the throttling device 4 can flow into the indoor heat exchanger 21 and then flow back to the compressor 1. In the third mode, the outdoor heat exchanger 3 can be defrosted or the energy storage device 7 can store cold energy.

[0080] In other embodiments, the reversing assembly 5 may also include a third four-way valve, and the exhaust port of the compressor 1, the return air port of the compressor 1, the indoor heat exchanger 21 and the outdoor heat exchanger 3 are respectively connected to different valve ports of the third four-way valve.

[0081] Further, see Figure 4 The heat pump system further includes an environment detection module 01, which is used to detect the ambient temperature. The environment detection module 01 is connected to the control device 100. The environment detection module 01 may include an indoor sensor and / or an outdoor sensor, the indoor sensor is arranged at the return air outlet of the indoor unit to detect the indoor temperature, and the outdoor heat exchanger 3 is arranged at the housing of the outdoor unit to detect the outdoor temperature.

[0082] Further, see Figure 4 The heat pump system further includes a temperature detection module 02, which is connected to the control device 100. The temperature detection module 02 can be arranged inside the energy storage device 7 to detect the temperature of the energy storage device 7.

[0083] Further, see Figure 4 The heat pump system further includes a pressure characteristic sensor 03, which is connected to the control device 100 and is used to detect the pressure characteristic of the heat pump system. In this embodiment, the pressure characteristic sensor 03 is arranged on the exhaust side of the compressor 1 to detect the high pressure characteristic of the heat pump system. In this embodiment, the pressure characteristic sensor 03 is a temperature sensor, which is used to detect the condensing temperature of the heat pump system, and the condensing temperature is used to characterize the condensing pressure of the system. In other embodiments, the pressure characteristic sensor 03 may be a pressure sensor.

[0084] In the embodiment of the present invention, refer to Figure 4 The control device 100 of the heat pump system includes: a processor 1001, such as a CPU, a memory 1002, and a timer 1003. Among them, these components are connected and communicated through a communication bus. The memory 1002 can be a high-speed RAM memory or a stable memory (non-volatile memory), such as a disk memory. The memory 1002 can also be a storage device independent of the aforementioned processor 1001.

[0085] Those skilled in the art will understand that Figure 4 The device structure shown in the figure does not constitute a limitation of the device, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0086] like Figure 4 As shown, the memory 1002 as a computer storage medium may include a control program for the heat pump system.

[0087] exist Figure 4 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 step operations of the control method of the heat pump system in the following embodiment.

[0088] An embodiment of the present invention further provides a control method for a heat pump system, which is applied to the above-mentioned heat pump system.

[0089] Reference Figure 5 , an embodiment of a control method of a heat pump system of the present application is proposed. In this embodiment, the control method of the heat pump system includes:

[0090] Step S10, controlling the reversing component to operate in a first state so that the indoor unit is connected to the exhaust port and the outdoor heat exchanger is connected to the return air port, and controlling the switching component to operate in a third state so that the second end of the refrigerant branch is connected to the exhaust port.

[0091] In this embodiment, the reversing assembly includes the first reversing valve and the second reversing valve, and the reversing assembly operates in the first state, including the first reversing valve operating in the second valve position and the second reversing valve operating in the fourth valve position, and the heat pump system is in the first mode. In other embodiments, the reversing assembly includes the third four-way valve, and the third four-way valve can operate in the heating valve position to connect the outdoor heat exchanger with the return air port and the exhaust port with the indoor unit.

[0092] In this embodiment, the switching component operating in the third state includes the switching component operating in the fifth valve position mentioned above.

[0093] Wherein, when the heat pump system includes the above-mentioned first control valve and second control valve, during the process in which the reversing component operates in the first state and the switching component operates in the third state, the first control valve and the second control valve are both opened.

[0094] During the operation of the reversing component in the first state and the switching component in the third state, refer to Figure 1 , part of the refrigerant discharged by the compressor flows through the indoor heat exchanger, the second control valve, the throttling device and the outdoor heat exchanger in turn, and then flows back to the compressor; another part of the refrigerant discharged by the compressor flows into the refrigerant branch, and the heat is stored in the energy storage device when the refrigerant flows through the energy storage device. The refrigerant flowing out of the refrigerant branch merges with the refrigerant flowing out of the indoor unit, and then flows through the throttling device and the outdoor heat exchanger in turn, and then flows back to the compressor. In the first mode, the indoor heat exchanger is in a condensing state, the outdoor heat exchanger is in an evaporating state, and the heat discharged by the compressor is stored in the energy storage device.

[0095] Step S20, when the heat pump system reaches the defrost start condition, the reversing component is controlled to operate in the second state to connect the outdoor heat exchanger with the exhaust port, and the switching component is controlled to operate in the fourth state to connect the second end of the refrigerant branch with the return air port.

[0096] The defrost start condition here specifically refers to the operating parameters of the heat pump system itself and / or the environmental parameters of the environment where the heat pump system is located when the outdoor heat exchanger is in a frosted state and needs to be defrosted. For example, the temperature of the outdoor heat exchanger is less than or equal to a preset temperature and lasts for a preset time.

[0097] When the heat pump system reaches the defrost start condition, the indoor fan in the indoor unit can be turned on or off. For example, when the exhaust port of the compressor corresponding to the second state is connected to the indoor unit, or when the return air port of the compressor corresponding to the second state is connected to the indoor unit and the second control valve is closed, the indoor fan can be turned on; when the return air port of the compressor corresponding to the second state is connected to the indoor unit and the second control valve is opened, the indoor fan can be turned off.

[0098] In this embodiment, when the reversing assembly operates in the second state, the indoor heat exchanger is connected to the exhaust port. The reversing assembly includes the first reversing valve and the second reversing valve mentioned above. The reversing assembly operates in the second state including the first reversing valve operating in the second valve position and the second reversing valve operating in the fourth valve position. The heat pump system is in the third mode mentioned above.

[0099] In this embodiment, the switching component operating in the fourth state includes the switching component operating in the aforementioned sixth valve position.

[0100] When the heat pump system includes the first control valve and the second control valve, during the operation of the reversing component in the second state and the operation of the switching component in the fourth state, the first control valve is opened and the second control valve (that is, the control valve in the indoor unit) is closed. The closing of the second control valve is conducive to improving the defrosting efficiency.

[0101] When the reversing component is operating in the second state and the switching component is operating in the fourth state, the refrigerant discharged from the compressor flows through the outdoor heat exchanger and the throttling device in sequence, and then partially or completely flows into the refrigerant branch. When the refrigerant flows through the energy storage device, it absorbs the energy in the energy storage device and then flows back to the compressor. When the second control valve is opened, a part of the refrigerant flowing out of the throttling device can flow into the indoor heat exchanger and then flow back to the compressor. The outdoor heat exchanger can use the heat from the compressor exhaust to melt frost.

[0102] A control method for a heat pump system is proposed in an embodiment of the present invention. The heat pump system stores heat in an energy storage device while heating the room through the operation coordination of the first operation state of the reversing component and the third state of the switching component. When the operation reaches the defrosting start condition, the outdoor heat exchanger can melt the frost by using the exhaust heat of the compressor through the operation coordination of the second state of the reversing component and the fourth state of the switching component. At the same time, the refrigerant after the outdoor heat exchanger heat exchange and throttling can flow through the energy storage device to absorb heat and then return to the compressor. During the defrosting process, the amount of low-temperature refrigerant flowing into the indoor unit can be effectively reduced, which can effectively reduce indoor temperature fluctuations, and a large amount of heat can be absorbed from the energy storage device, which can effectively improve the defrosting efficiency of the outdoor heat exchanger. In addition, the reduction in the amount of refrigerant flowing into the indoor heat exchanger is conducive to reducing the operating noise of the indoor unit.

[0103] In other embodiments, when the reversing assembly operates in the second state, the indoor heat exchanger may be connected to the return air port, for example, the first reversing valve operates in the first valve position, and the second reversing valve operates in the fourth valve position.

[0104] In other embodiments, when the indoor heat exchanger is connected to the compressor exhaust port when the reversing assembly is operating in the second state, the second control valve may also be opened and operated in throttling mode to maintain heat delivery to the room, and the indoor fan operates at the lowest speed, thereby maintaining heat delivery to the room during the defrosting process, achieving defrosting while improving indoor comfort.

[0105] Further, based on the above embodiment, another embodiment of the control method of the heat pump system of the present application is proposed. In this embodiment, referring to Figure 6 , the process of controlling the reversing component to operate in the second state so that the outdoor heat exchanger is connected to the exhaust port, and controlling the switching component to operate in the fourth state so that the second end of the refrigerant branch is connected to the return air port, further includes:

[0106] Step S30: controlling the operation of the compressor according to the energy demand parameter of the energy storage device and / or the pressure characteristic representing the system pressure of the heat pump system.

[0107] In this embodiment, the pressure feature includes a high pressure feature characterizing the high pressure of the system. In other embodiments, the pressure feature may also include a low pressure feature characterizing the low pressure of the system.

[0108] The pressure characteristic can be detected by the detection module in the heat pump system, or can be determined based on the data detected by the detection module in the heat pump system. In this embodiment, the pressure characteristic includes the exhaust temperature or the condensing pressure determined based on the exhaust temperature or the exhaust pressure or the saturation temperature corresponding to the exhaust pressure.

[0109] The energy demand parameter is specifically a state parameter that characterizes the amount of heat demanded by the application subject corresponding to the energy storage device. The energy demand parameter can be determined based on detection data inside the energy storage device and / or detection data of the environment where the heat pump system is located.

[0110] In one implementation of this embodiment, during the operation of the reversing component in the second state and the operation of the switching component in the fourth state, the target frequency of the compressor is determined according to the energy demand parameter, and the compressor is controlled to operate at the determined target frequency, or the current frequency of the compressor is adjusted according to the energy demand parameter. In another implementation of this embodiment, during the operation of the reversing component in the second state and the operation of the switching component in the fourth state, the target frequency of the compressor is determined according to the pressure characteristic, and the compressor is controlled to operate at the determined target frequency, or the current frequency of the compressor is adjusted according to the pressure characteristic. In another implementation of this embodiment, during the operation of the reversing component in the second state and the operation of the switching component in the fourth state, the target frequency of the compressor is determined according to the energy demand parameter and the pressure characteristic, and the compressor is controlled to operate at the determined target frequency, or the current frequency of the compressor is adjusted according to the energy demand parameter and the pressure characteristic. In another implementation of this embodiment, the compressor operating frequency is first controlled according to the energy demand parameter, and then the compressor operating frequency is controlled according to the pressure characteristic, or the compressor operating frequency is first controlled according to the pressure characteristic, and then the compressor operating frequency is controlled according to the energy demand parameter.

[0111] In this embodiment, the defrost process adapts to the energy demand parameters of the energy storage device to control the operating frequency of the compressor, which is beneficial to ensure that the heat of the energy storage device during the defrost process can meet both the defrost demand and the heat demand of the user. The defrost process adapts to the pressure characteristics to control the operating frequency of the compressor, which is beneficial to ensure that the system pressure can be maintained within the range of reliable operation, thereby improving the reliability of system operation during the defrost process.

[0112] Furthermore, in this embodiment, the step of controlling the operation of the compressor according to the energy requirement parameters of the energy storage device includes: correcting the energy requirement parameters according to a target correction value to obtain a target frequency of the compressor; controlling the compressor to operate at the target frequency; wherein the target correction value is determined based on the exhaust parameters of the compressor.

[0113] The exhaust parameters include exhaust pressure and / or exhaust temperature, etc. The exhaust parameters can be specifically obtained by detection by a detection module disposed on the exhaust side of the compressor or calculated based on detection data of the detection module, etc.

[0114] The exhaust parameter may be the current exhaust parameter of the compressor, or may be a parameter determined based on a plurality of exhaust characteristic parameters of the compressor detected after the preset mode is started.

[0115] Different exhaust parameters correspond to different target correction values.

[0116] In this embodiment, the target correction value is a correction coefficient, and the product of the energy requirement parameter and the correction coefficient is used as the target frequency. In other embodiments, the target correction value may also be a correction amplitude, and the sum of the energy requirement parameter and the correction amplitude is used as the target frequency.

[0117] In this embodiment, the energy requirement parameter is corrected according to the target correction value determined by the exhaust parameter of the compressor to obtain the operating frequency of the compressor, which is beneficial to meeting the energy demand of the energy storage device during the defrosting process while improving the operating reliability of the compressor.

[0118] Furthermore, in this embodiment, the step of controlling the operation of the compressor according to the pressure characteristic of the heat pump system characterizing the system pressure includes: when the pressure characteristic is less than or equal to a preset pressure characteristic, controlling the operation of the compressor according to the pressure characteristic and a target pressure characteristic.

[0119] The preset pressure characteristic is less than the protection pressure characteristic of the heat pump system, and the protection pressure characteristic is a preset pressure characteristic critical value used to distinguish whether the heat pump system has a risk of reliability problems. The preset pressure characteristic is used to characterize the preset pressure of the heat pump system, and the preset pressure characteristic can be a preset pressure or a preset temperature corresponding to the preset pressure.

[0120] The target pressure characteristic is specifically a preset target value that the pressure characteristic needs to reach when the energy efficiency is optimal. The target pressure characteristic is used to characterize the target pressure of the heat pump system. The target pressure characteristic can be a target pressure or a target temperature corresponding to the target pressure.

[0121] In one implementation of this embodiment, the pressure characteristic difference between the pressure characteristic and the target pressure characteristic is determined; and the operation of the compressor is controlled according to the pressure characteristic difference. Specifically, when the pressure characteristic difference is greater than a first preset threshold, the compressor is controlled to operate at a reduced frequency; when the pressure characteristic difference is less than or equal to a second preset threshold, the compressor is controlled to operate at an increased frequency; wherein the second preset threshold is less than or equal to the first preset threshold. In this embodiment, the pressure characteristic difference is a calculation result obtained by subtracting the target pressure characteristic from the pressure characteristic. If the second preset threshold is less than the first preset threshold, then when the pressure characteristic difference is greater than the second preset threshold and less than or equal to the first preset threshold, the compressor can be controlled to maintain the current frequency operation.

[0122] For example, the pressure characteristic difference X=Tc-Tc_TARGET, Tc_TARGET is the target pressure characteristic, Tc is the high pressure characteristic of the system, and in this embodiment, Tc is the condensation temperature, then:

[0123] When X>1, the compressor frequency decreases by 5% of the current frequency every 20 seconds;

[0124] When -1<X≤1, the compressor frequency maintains the current frequency;

[0125] When X≤-1, the compressor frequency increases by 3% of the current frequency every 20 seconds.

[0126] In another implementation of this embodiment, when the pressure characteristic is greater than the target pressure characteristic, the compressor may be controlled to reduce the frequency; when the pressure characteristic is less than the target pressure characteristic, the compressor may be controlled to increase the frequency.

[0127] The frequency adjustment value when the compressor reduces the frequency is greater than the frequency adjustment value when the compressor increases the frequency.

[0128] The frequency adjustment value during the process of reducing or increasing the frequency of the compressor can be a preset fixed value, or a value determined according to the actual operation of the heat pump system. For example, it can be determined based on the temperature of the outdoor heat exchanger and / or the outdoor ambient temperature and / or the temperature difference between the temperature of the energy storage device and the set temperature.

[0129] In this embodiment, when the pressure characteristic is less than or equal to the preset pressure characteristic, the system will not have reliability problems. At this time, the operation of the compressor is controlled according to the pressure characteristic and the target pressure characteristic. The operating frequency of the compressor can be increased or decreased to adapt to the actual situation of the pressure characteristic and the target pressure characteristic, so that the pressure characteristic can reach the target pressure characteristic, thereby effectively improving the system energy efficiency while improving the defrosting process and indoor comfort.

[0130] Furthermore, in this embodiment, the step of controlling the operation of the compressor according to the pressure characteristic of the heat pump system includes: when the pressure characteristic is greater than the preset pressure characteristic, limiting the compressor from operating at an increased frequency, controlling the compressor from operating at a reduced frequency, or controlling the compressor to stop.

[0131] Limiting the compressor from increasing the frequency includes: controlling the compressor to operate at a frequency less than or equal to a preset frequency, or controlling the compressor to maintain the current frequency, or controlling the compressor to increase the frequency at a rate less than a preset rate.

[0132] The frequency adjustment value when the compressor is operating at reduced frequency can be a pre-set fixed value, or a value determined according to the actual operating conditions of the heat pump system. For example, it can be determined based on the temperature of the outdoor heat exchanger and / or the outdoor ambient temperature and / or the temperature difference between the temperature of the energy storage device and the set temperature.

[0133] In this embodiment, when the pressure characteristic is greater than the preset pressure characteristic, the system may have reliability problems. At this time, the compressor is limited to increase the frequency of operation or control the compressor to reduce the frequency of operation, thereby avoiding excessive pressure characteristics and improving the reliability of the system operation during the defrost process.

[0134] Furthermore, in this embodiment, the frequency adjustment value is determined according to the pressure characteristic; the compressor is controlled to reduce the current operating frequency according to the frequency adjustment value; wherein the frequency adjustment value is positively correlated with the pressure characteristic. Specifically, the pressure characteristic interval in which the pressure characteristic is located can be determined, and the frequency adjustment value can be determined according to the pressure characteristic interval. Alternatively, the frequency adjustment value can be calculated by the pressure characteristic. The larger the pressure characteristic, the greater the frequency reduction amplitude of the compressor.

[0135] Here, the frequency adjustment value is determined based on the pressure characteristics to control the compressor to reduce the current operating frequency, which is beneficial to further improve the system operation reliability.

[0136] Furthermore, in the present embodiment, the step of limiting the compressor from increasing the frequency or controlling the compressor from decreasing the frequency includes: when the pressure characteristic is less than or equal to a first pressure characteristic threshold, executing the step of limiting the compressor from increasing the frequency; when the pressure characteristic is greater than the first pressure characteristic threshold and less than or equal to a second pressure characteristic threshold, executing the step of controlling the compressor from decreasing the frequency; when the pressure characteristic is greater than the second pressure characteristic threshold, executing the step of stopping the compressor; wherein the first pressure characteristic threshold is greater than the preset pressure characteristic, and the second pressure characteristic threshold is greater than the first pressure characteristic threshold.

[0137] The second pressure characteristic threshold here is the above-mentioned protection pressure characteristic, and the first pressure characteristic threshold is used to distinguish the risk of reliability problems in the heat pump system.

[0138] In this embodiment, when the pressure characteristic is less than or equal to the first pressure characteristic threshold, the probability of the heat pump system having a reliability risk is very low. At this time, limiting the compressor frequency increase is beneficial to reducing unnecessary compressor frequency reduction or shutdown, so as to effectively ensure reliable operation while effectively improving the defrosting effect; when the pressure characteristic is between the first pressure characteristic threshold and the second pressure characteristic threshold, the probability of the heat pump system having a reliability risk is relatively high. At this time, the compressor frequency reduction operation is beneficial to reducing compressor shutdown, so as to ensure reliable system operation while maintaining normal defrosting operation; when the pressure characteristic is greater than the second pressure characteristic threshold, the heat pump system has a reliability problem. At this time, the compressor shutdown is beneficial to protecting the heat pump system.

[0139] Furthermore, in the present embodiment, the step of limiting the frequency increase operation of the compressor includes: when the pressure characteristic is less than or equal to a third pressure characteristic threshold, controlling the compressor to increase the frequency and operate at a rate less than a preset rate; when the pressure characteristic is greater than the third pressure characteristic threshold and the pressure characteristic is less than or equal to the first pressure characteristic threshold, controlling the compressor to maintain the current frequency operation; wherein the third pressure characteristic threshold is greater than the preset pressure characteristic, and the third pressure characteristic threshold is less than the first pressure characteristic threshold.

[0140] The preset rate here can be a pre-set fixed rate, or it can be a rate determined according to the actual operating state of the heat pump system, for example, it can be determined according to the exhaust temperature of the compressor and / or the temperature of the outdoor heat exchanger and / or the outdoor ambient temperature and / or the temperature difference between the energy storage device and the set temperature.

[0141] In this embodiment, when the pressure characteristic is less than or equal to the third pressure characteristic threshold, the risk of reliability problems is extremely low, and the compressor is controlled to meet the frequency increase, which is beneficial to improving the defrost efficiency while ensuring the system operation reliability; when the pressure characteristic is between the third pressure characteristic threshold and the first pressure characteristic threshold, the risk of reliability problems exists but is relatively low. At this time, the compressor is controlled to maintain the current frequency operation, which is beneficial to reduce unavoidable frequency reduction, improve the defrost effect while ensuring the system operation reliability.

[0142] In order to better understand the heat pump control method mentioned in this embodiment, the present embodiment is described below with reference to a specific example:

[0143] When the system high pressure characteristic Tc>56℃, the control method is as follows:

[0144] When 56℃<Tc≤58℃, the compressor increases frequency slowly, increasing by 1 Hz every 60 seconds;

[0145] 58℃<Tc≤60℃, the compressor frequency is maintained and frequency increase is not allowed;

[0146] 60℃<Tc≤62℃, the compressor reduces the current frequency by 15%

[0147] 60℃<Tc≤64℃, the compressor reduces the current frequency by 30%;

[0148] Tc>64℃, protection shutdown;

[0149] Among them, 56°C is the above-mentioned preset pressure characteristic, 58°C is the above-mentioned third pressure characteristic threshold, 60°C is the above-mentioned first pressure characteristic threshold, and 64°C is the above-mentioned second pressure characteristic threshold.

[0150] Further, based on any of the above embodiments, another embodiment of the control method of the heat pump system of the present application is proposed. Figure 7 , before the step of controlling the operation of the compressor according to the energy demand parameter of the energy storage device and / or the pressure characteristics of the system pressure of the heat pump system, it also includes:

[0151] Step S01, when the reversing component operates in the second state and the switching component operates in the fourth state, obtaining an actual energy requirement value of the energy storage device under the current working condition and a rated energy requirement value of the energy storage device;

[0152] The actual energy demand value is related to the actual operating conditions of the energy storage device and may change with the actual operating conditions.

[0153] The rated energy demand is an energy demand value that is related to the inherent properties of the energy storage device and does not change with actual operating conditions.

[0154] Step S02: determining the energy requirement parameter according to the actual energy requirement value and the rated energy requirement value.

[0155] In this embodiment, the sum of the actual energy demand value and the rated energy demand value is determined as the energy demand parameter. In other embodiments, the rated energy demand value can also be used to determine the correction coefficient, and the actual energy demand value is corrected according to the correction coefficient to obtain the energy demand parameter.

[0156] In this embodiment, the energy demand parameters of the energy storage device are determined in combination with the actual energy demand value and the rated energy demand value, which is beneficial to ensure that the determined energy demand parameters can accurately reflect the capacity requirements of the energy storage device in the initial stage, thereby facilitating further improving the accuracy of the adjustment of the compressor operating frequency, thereby further ensuring that the energy demand corresponding to the energy storage device in the defrost stage is met while improving the defrost efficiency and indoor comfort.

[0157] In other embodiments, one of the actual energy demand value and the rated energy demand value may be used as the energy demand parameter.

[0158] Furthermore, in this embodiment, the process of obtaining the actual energy requirement value is as follows: obtaining the energy storage temperature of the energy storage device and the outdoor ambient temperature corresponding to the heat pump system; and determining the actual energy requirement value according to the energy storage temperature and the outdoor ambient temperature.

[0159] The energy storage temperature is detected by the above-mentioned temperature sensor. The outdoor environment temperature is detected by the above-mentioned environment detection module.

[0160] Different energy storage temperatures and different outdoor ambient temperatures correspond to different actual energy demand values. The actual energy demand value is negatively correlated with the outdoor ambient temperature, and the actual energy demand value is negatively correlated with the energy storage temperature.

[0161] Specifically, a correspondence between the energy storage temperature, the outdoor ambient temperature and the actual energy requirement value can be established in advance. The correspondence may include a calculation formula, a mapping relationship, etc. Based on the correspondence, the actual energy requirement value corresponding to the current energy storage temperature and the outdoor ambient temperature can be determined.

[0162] Furthermore, more than one correspondence relationship between the energy storage temperature, the outdoor ambient temperature and the actual energy demand value can be pre-set, and the target correspondence relationship can be determined in more than one correspondence relationship 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, and the actual energy demand value corresponding to the current energy storage temperature and the outdoor ambient temperature is determined based on the target correspondence relationship.

[0163] For example, the corresponding relationship between the outdoor environment temperature T4, the energy storage temperature Tw and the actual energy demand value Aw is shown in Table 1 below:

[0164]

[0165] Table 1

[0166] Based on this, by determining the interval of the outdoor ambient temperature in the above table and the interval of the energy storage temperature in the above table, the energy demand value obtained by matching the two intervals is used as the actual energy demand value.

[0167] In this embodiment, the operating conditions of the defrost mode can be accurately reflected by combining the outdoor ambient temperature and the energy storage temperature. Therefore, the actual energy requirement value is determined according to the outdoor ambient temperature and the energy storage temperature, which is beneficial to ensure that the actual energy requirement value can accurately reflect the actual energy requirement of the energy storage device under the defrost condition, thereby facilitating further improving the accuracy of the compressor frequency operation control, further ensuring that the corresponding energy usage requirements of the energy storage device are met while improving the defrost efficiency and indoor comfort.

[0168] In other embodiments, the actual energy requirement value may also be determined based on one of the outdoor ambient temperature and the energy storage temperature, or based on other parameters other than the outdoor ambient temperature and the energy storage temperature. The other parameters here may 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 surface temperature and the outer surface temperature of the energy storage device and / or the temperature difference change rate between the inner surface temperature and the outer surface temperature of the energy storage device, and / or the temperature difference change rate between the inner surface temperature and the outer surface temperature of the energy storage device, and the like.

[0169] Furthermore, in this embodiment, the volume of the energy storage device for storing energy storage material is obtained, and the rated energy requirement is determined according to the volume. The volume is positively correlated with the rated energy requirement.

[0170] For example, the volume and rated energy demand values ​​can be shown in Table 2 below:

[0171] Volume / L Rated energy demand Hw / kW 150 2.8 200 3.6

[0172] Table 2

[0173] In this embodiment, the rated energy requirement is determined according to the volume of the energy storage device, which is conducive to accurately reflecting the energy requirement required by the properties of the energy storage device itself during the energy storage process, thereby facilitating further improving the accuracy of the compressor frequency operation control, further ensuring that the energy usage requirements corresponding to the energy storage device are met while improving the defrosting efficiency and indoor comfort.

[0174] In other embodiments, the rated energy requirement value here may also be determined according to the shell thickness and material type of the energy storage device.

[0175] Further, based on any of the above embodiments, another embodiment of the control method of the heat pump system of the present application is proposed. In this embodiment, referring to Figure 8 The step of controlling the operation of the compressor according to the energy demand parameter of the energy storage device and / or the pressure characteristic of the heat pump system representing the system pressure comprises:

[0176] Step S31, controlling the operation of the compressor according to the energy demand parameter;

[0177] Step S32: When the operation of the heat pump system reaches a preset condition, the operation of the compressor is controlled according to the pressure characteristic.

[0178] The specific implementation process of controlling the operation of the compressor according to the energy demand parameters and controlling the operation of the compressor according to the pressure characteristics can be found in the above embodiments, which will not be described in detail here.

[0179] The preset conditions are the conditions that need to be met by the heat pump system's own operating parameters and / or the environmental state parameters of the environment in which the heat pump system is located when the reversing component switches to the second state and the compressor control mode needs to be switched after the switching component switches to the fourth state.

[0180] In this embodiment, the preset condition includes at least one of the following conditions:

[0181] Condition 1: the operation time of the reversing component in the second state and the switching component in the fourth state is greater than a preset time;

[0182] Condition 2: The current pressure characteristic of the heat pump system that represents the system pressure is greater than a fourth pressure characteristic threshold.

[0183] Condition 1 indicates whether there is a risk of poor energy efficiency in the heat pump system after the defrost phase, and condition 2 indicates that there is a reliability risk in the heat pump system.

[0184] The fourth pressure characteristic threshold is less than the second pressure characteristic threshold. In this embodiment, the fourth pressure characteristic threshold is equal to the third pressure characteristic threshold. In other embodiments, the fourth pressure characteristic threshold may also be greater than or less than the third pressure characteristic threshold.

[0185] In this embodiment, after the defrosting operation of the heat pump system, the compressor frequency is first controlled according to the energy demand parameters of the energy storage device to reduce the impact on the energy demand of the energy storage device while achieving defrosting to ensure indoor comfort. When the operation meets the preset conditions, indicating that the defrosting energy efficiency is poor or there is a risk of reliable operation, the compressor operation is further controlled according to the pressure characteristics characterizing the system pressure to improve the defrosting efficiency, ensure indoor comfort and improve the reliability of the heat pump system operation.

[0186] In addition, an embodiment of the present invention further proposes a storage medium, on which a control program of a heat pump system is stored. When the control program of the heat pump system is executed by a processor, the relevant steps of any embodiment of the control method of the heat pump system are implemented.

[0187] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0188] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0189] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, including a number of instructions for a terminal device (which can be a mobile phone, computer, server, heat pump system, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0190] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A control method for a heat pump system, characterized in that: The heat pump system comprises a refrigerant main circuit, a refrigerant branch circuit and a switching component, wherein the refrigerant main circuit comprises an indoor unit, a throttling device, an outdoor heat exchanger, a reversing component and a compressor, wherein the indoor unit, the throttling device and the outdoor heat exchanger are connected in sequence, the refrigerant branch circuit comprises an energy storage device, a pipeline between the throttling device and the indoor unit is connected to a first end of the refrigerant branch circuit, a second end of the refrigerant branch circuit, an exhaust port of the compressor and an air return port of the compressor are all connected to the switching component, and the control method of the heat pump system comprises the following steps: Control the reversing component to operate in a first state so that the indoor unit is connected to the exhaust port and the outdoor heat exchanger is connected to the return air port, and control the switching component to operate in a third state so that the second end of the refrigerant branch is connected to the exhaust port; When the heat pump system reaches the defrost start condition, the reversing component is controlled to operate in the second state to connect the outdoor heat exchanger with the exhaust port, and the switching component is controlled to operate in the fourth state to connect the second end of the refrigerant branch with the return air port.

2. The control method of the heat pump system according to claim 1, characterized in that: The process of controlling the reversing component to operate in the second state so that the outdoor heat exchanger is connected to the exhaust port, and controlling the switching component to operate in the fourth state so that the second end of the refrigerant branch is connected to the return air port, further includes: The operation of the compressor is controlled according to the energy demand parameter of the energy storage device and / or the pressure characteristic of the heat pump system representing the system pressure.

3. The control method of the heat pump system according to claim 2, characterized in that: The step of controlling the operation of the compressor according to the pressure characteristic representing the system pressure of the heat pump system comprises: When the pressure characteristic is less than or equal to a preset pressure characteristic, controlling the operation of the compressor according to the pressure characteristic and a target pressure characteristic; When the pressure characteristic is greater than the preset pressure characteristic, the compressor is restricted from operating at an increased frequency, or the compressor is controlled to operate at a reduced frequency, or the compressor is controlled to stop.

4. The control method of the heat pump system according to claim 3, characterized in that: The step of controlling the operation of the compressor according to the pressure characteristic and the target pressure characteristic comprises: determining a pressure characteristic difference between the pressure characteristic and the target pressure characteristic; When the pressure characteristic difference is greater than a first preset threshold, controlling the compressor to operate at a reduced frequency; When the pressure characteristic difference is less than or equal to a second preset threshold, controlling the compressor to increase the frequency of operation; The second preset threshold is less than or equal to the first preset threshold.

5. The control method of the heat pump system according to claim 3, characterized in that: The step of limiting the compressor from running at an increased frequency or controlling the compressor from running at a reduced frequency or controlling the compressor to stop comprises: When the pressure characteristic is less than or equal to a first pressure characteristic threshold, executing the step of limiting the compressor up-frequency operation; When the pressure characteristic is greater than the first pressure characteristic threshold and less than or equal to the second pressure characteristic threshold, executing the step of controlling the compressor to operate at reduced frequency; When the pressure characteristic is greater than the second pressure characteristic threshold, executing the step of stopping the compressor; Among them, the first pressure characteristic threshold is greater than the preset pressure characteristic, and the second pressure characteristic threshold is greater than the first pressure characteristic threshold.

6. The control method of the heat pump system according to claim 5, characterized in that: The step of limiting the compressor from running at an increased frequency comprises: When the pressure characteristic is less than or equal to a third pressure characteristic threshold, controlling the compressor to increase frequency and operate at a rate less than a preset rate; When the pressure characteristic is greater than the third pressure characteristic threshold and the pressure characteristic is less than or equal to the first pressure characteristic threshold, controlling the compressor to maintain the current frequency operation; Among them, the third pressure characteristic threshold is greater than the preset pressure characteristic, and the third pressure characteristic threshold is less than the first pressure characteristic threshold.

7. The control method of the heat pump system according to claim 5, characterized in that: The step of controlling the compressor to operate at reduced frequency comprises: determining a frequency adjustment value according to the pressure characteristic; controlling the compressor to reduce the current operating frequency according to the frequency adjustment value; Wherein, the frequency adjustment value is positively correlated with the pressure characteristic.

8. The control method of the heat pump system according to claim 2, characterized in that: The step of controlling the operation of the compressor according to the energy demand parameter of the energy storage device comprises: Correcting the energy demand parameter according to the target correction value to obtain the target frequency of the compressor; controlling the compressor to operate at the target frequency; Wherein, the target correction value is determined according to the exhaust parameter of the compressor.

9. The control method of the heat pump system according to claim 2, characterized in that: Before the step of controlling the operation of the compressor according to the energy demand parameter of the energy storage device and / or the pressure characteristic of the heat pump system characterizing the system pressure, the method further includes: In the process of the reversing component operating in the second state and the switching component operating in the fourth state, obtaining an actual energy requirement value of the energy storage device under the current working condition and a rated energy requirement value of the energy storage device; The energy demand parameter is determined according to the actual energy demand value and the rated energy demand value.

10. The control method of the heat pump system according to claim 9, characterized in that: The step of obtaining the actual energy demand value of the energy storage device under the current working condition comprises: Acquire the energy storage temperature of the energy storage device and the outdoor ambient temperature corresponding to the heat pump system; The actual energy requirement value is determined according to the energy storage temperature and the outdoor ambient temperature.

11. The control method of the heat pump system according to claim 9, characterized in that: The step of obtaining the rated energy demand value of the energy storage device comprises: Obtaining the volume of the energy storage device for storing energy storage material; The rated energy demand is determined based on the volume.

12. The control method of a heat pump system according to any one of claims 2 to 11, characterized in that: The step of controlling the operation of the compressor according to the energy demand parameter of the energy storage device and / or the pressure characteristic of the heat pump system representing the system pressure comprises: Controlling the operation of the compressor according to the energy demand parameter; When the operation of the heat pump system reaches a preset condition, the operation of the compressor is controlled according to the pressure characteristic.

13. The control method of the heat pump system according to claim 12, characterized in that: The preset condition includes at least one of the following conditions: The operation time of the reversing component operating in the second state and the switching component operating in the fourth state is greater than a preset time; The pressure characteristic of the heat pump system currently representing the system pressure is greater than a fourth pressure characteristic threshold.

14. The control method of a heat pump system according to any one of claims 1 to 11, characterized in that: The control method of the heat pump system further includes: When the reversing component operates in the second state and the switching component operates in the fourth state, the control valve in the indoor unit is controlled to be closed.

15. A heat pump system, characterized in that: The heat pump system includes: a memory, a processor, and a control program of the heat pump system stored in the memory and executable on the processor. When the control program of the heat pump system is executed by the processor, the steps of the control method of the heat pump system as described in any one of claims 1 to 14 are implemented.

16. A storage medium, characterized in that: The storage medium stores a control program of the heat pump system, and when the control program of the heat pump system is executed by the processor, the steps of the control method of the heat pump system according to any one of claims 1 to 14 are implemented.

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