Low-temperature control method and system of heat pump system, storage medium and vehicle

Abstract

The invention provides a low-temperature control method and system of a heat pump system, a storage medium and a vehicle. The method comprises the steps that after a whole vehicle is powered on, the water temperature of an electric drive outlet of an electric drive loop is obtained; when the water temperature of the electrically-driven outlet is lower than a first preset temperature threshold value, electrically-driven active heating is controlled to be started; when a passenger compartment heating request is received, the pressure of an air suction port of a compressor is obtained; and when the pressure of the air suction port is lower than the preset pressure threshold value, the compressor is controlled to enter a compressor pulse starting mode, and the compressor pulse starting mode is started in the mode that the compressor runs for the first duration at the preset low rotating speed and then stops to wait for the second duration. According to the invention, a PTC heater does not need to be additionally arranged, and the R134a heat pump system can be started and continuously and stably operated at the environment temperature of-30 DEG C or above.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a low-temperature control method, system, storage medium and vehicle for a heat pump system. Background Art

[0002] With the development of new energy and the improvement of environmental awareness, the market share of electric vehicles has gradually increased. In order to improve the energy utilization rate of electric vehicles and reduce the energy consumption of the whole vehicle, more and more electric vehicles are equipped with heat pump systems as standard, but most of the heat pump systems using R134a cannot start and continue to operate stably at ambient temperatures of -20℃ or below, and fail to achieve the purpose of reducing energy consumption.

[0003] The current technology is to add a PTC heater (high-pressure liquid or air heater) upstream of the chiller in the coolant loop, and heat the coolant through the PTC heater to increase the refrigerant temperature in the coolant loop, so that the compressor can start in a low-temperature environment. However, if the refrigerant is heated to meet the low-pressure requirement only by the PTC heater, it will take more than 30 minutes to wait, which cannot meet the customer's heating needs, and starting the compressor at an ambient temperature below -20°C / low pressure below 1 bar is likely to cause damage to the compressor. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a low-temperature control method, system, storage medium and vehicle for a heat pump system, which can start and continuously and stably operate an R134a heat pump system at an ambient temperature of -30°C or above without the need for an additional PTC heater.

[0005] One aspect of an embodiment of the present application provides a low-temperature control method for a heat pump system. The method includes: after the vehicle is powered on, obtaining the electric drive outlet water temperature of the electric drive circuit; when the electric drive outlet water temperature is lower than a first predetermined temperature threshold, controlling to start active electric drive heating; when a passenger compartment heating request is received, obtaining the air intake pressure of the compressor; when the air intake pressure is lower than a predetermined pressure threshold, controlling to enter a compressor pulse start mode, wherein the compressor pulse start mode is started by running the compressor at a predetermined low speed for a first time period, and then stopping to wait for a second time period.

[0006] Further, the heat pump system includes a first throttle valve, a second throttle valve, a third throttle valve, a first heat exchanger, a second heat exchanger and a third heat exchanger, one end of the first throttle valve is connected to the exhaust port of the compressor through the first heat exchanger, the other end of the first throttle valve is connected to the intake port of the compressor through the second heat exchanger, the two ends of the second throttle valve are respectively connected to the intake port and the exhaust port of the compressor, one end of the third throttle valve is connected to the second heat exchanger, and the other end of the third throttle valve is connected to the intake port of the compressor through the third heat exchanger, and the method also includes: in the compressor pulse start mode, controlling the first throttle valve to start, and the second throttle valve and the third throttle valve to close.

[0007] Furthermore, the method further comprises: in the compressor pulse start mode, controlling the compressor to run at a predetermined low speed for a first predetermined time, and then stopping and waiting for a second predetermined time, repeating the method for a maximum of a predetermined number of times.

[0008] Furthermore, the method also includes: after the compressor pulse start reaches the predetermined number of times, when the suction port pressure of the compressor is still lower than the predetermined pressure threshold, then after the state of the suction port pressure being lower than the predetermined pressure threshold is maintained for more than a third predetermined time period, controlling to enter the compressor pulse start mode.

[0009] Furthermore, the method also includes: during the operation of the compressor pulse start mode, continuously obtaining the suction port pressure of the compressor; when the suction port pressure is not lower than the predetermined pressure threshold, controlling the determination of entering the heat pump condition; when the heat pump condition is met, controlling entering the heat pump mode.

[0010] Furthermore, when the heat pump condition is met, the control enters the heat pump mode, including: when the suction port pressure is in the range of 0.9 bar-1.1 bar and runs for less than the fourth predetermined time, or the suction port pressure is not less than 1.1 bar, it is determined that the heat pump condition is met, and the control enters the heat pump mode. The method also includes: when the suction port pressure is in the range of 0.9 bar-1.1 bar and runs for more than the fifth predetermined time, the compressor is controlled to stop.

[0011] Furthermore, the method also includes: when the water temperature at the electric drive outlet is higher than a second predetermined temperature threshold, controlling to shut down the active heating of the electric drive; and when the water temperature at the electric drive outlet is not lower than a third predetermined temperature threshold, controlling to determine the conditions for entering the heat pump.

[0012] Furthermore, the method further includes: when the water temperature at the electric drive outlet is not lower than a third predetermined temperature threshold, controlling the determination of entering a heat pump condition.

[0013] Another aspect of an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the low-temperature control method of the heat pump system as described above are implemented.

[0014] Another aspect of the embodiments of the present application provides a low temperature control system for a heat pump system. The maximum vehicle speed control system includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the low temperature control method for the heat pump system as described above when executing the computer program.

[0015] Another aspect of the embodiment of the present application provides a vehicle. The vehicle includes a heat pump system and a low temperature control system of the heat pump system as described above, the heat pump system includes a refrigerant circuit and an electric drive circuit, the refrigerant circuit includes a first refrigerant circuit and a second refrigerant circuit, the first refrigerant circuit includes a compressor, a first heat exchanger, a first throttle valve, a second heat exchanger and a second throttle valve, the exhaust port of the compressor is connected to the first end of the first heat exchanger, the second end of the first heat exchanger is connected to one end of the first throttle valve, the other end of the first throttle valve is connected to the air intake port of the compressor through the second heat exchanger, the two ends of the second throttle valve are respectively connected to the air intake port and the exhaust port of the compressor, the second refrigerant circuit includes a third throttle valve and a third heat exchanger, one end of the third throttle valve is connected to the second end of the second heat exchanger, and the other end of the third throttle valve is connected to the air intake port of the compressor through the third heat exchanger, and the low temperature control system is used to control the heat pump system.

[0016] The low temperature control method of the heat pump system in one or more embodiments of the present application can quickly increase the temperature of the refrigerant in the heat pump system, so that the low pressure can be quickly increased to the pressure requirement for continuous operation, thereby entering the normal heat pump mode more quickly to meet customer heating needs.

[0017] The low temperature control method of the heat pump system of one or more embodiments of the present application can expand the operating temperature of the heat pump to -30°C through electric drive active heating and compressor pulse start mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a heat pump system according to an embodiment of the present application.

[0019] Figure 2 This is a flow chart of a low temperature control method for a heat pump system according to an embodiment of the present application.

[0020] Figure 3 A specific flow chart of the low temperature control method of the heat pump system of the present application.

[0021] Figure 4 This is a schematic structural diagram of a heat pump system in an embodiment of the present application in an electric drive active heating and compressor pulse start mode.

[0022] Figure 5 This is a schematic diagram of the structure of a heat pump system in heat pump mode according to an embodiment of the present application.

[0023] Figure 6 A schematic block diagram of a low-temperature control system of a heat pump system according to an embodiment of the present application. DETAILED DESCRIPTION

[0024] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are merely examples of devices consistent with some aspects of the present application as detailed in the appended claims.

[0025] The low temperature control method, system, storage medium and vehicle of the heat pump system of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments and implementations can be combined with each other.

[0026] Figure 1 The schematic diagram of the structure of a heat pump system 100 according to an embodiment of the present application is disclosed. Figure 1 As shown, the heat pump system 100 includes a refrigerant circuit 110, a passenger compartment circuit 140, a battery circuit 150 and an electric drive circuit 160. The passenger compartment circuit 140 includes a heater water pump HCWP. The battery circuit 150 includes a battery 151 and a battery water pump BCPF. The electric drive circuit 160 includes an electric drive 161 and an electric drive water pump EDCP.

[0027] The refrigerant circuit 110 includes a first refrigerant circuit 120 and a second refrigerant circuit 130. The first refrigerant circuit 120 includes a compressor 111, a first heat exchanger 112, a first throttle valve BEXV, a second heat exchanger 113, and a second throttle valve AEXV. The exhaust port of the compressor 111 is connected to the first end of the first heat exchanger 112, the second end of the first heat exchanger 112 is connected to one end of the first throttle valve BEXV, the other end of the first throttle valve BEXV is connected to the air intake port of the compressor 111 through the second heat exchanger 113, and the two ends of the second throttle valve AEXV are respectively connected to the air intake port and the exhaust port of the compressor 111. The second refrigerant circuit 130 includes a third throttle valve EEXV and a third heat exchanger 114. One end of the third throttle valve EEXV is connected to the second end of the second heat exchanger 113, and the other end of the third throttle valve EEXV is connected to the air intake port of the compressor 111 through the third heat exchanger 114. The first heat exchanger 112 may be a water-cooled condenser, and the third heat exchanger 114 may be an evaporator. The first throttle valve BEXV, the second throttle valve AEXV, and the third throttle valve EEXV may be electronic expansion valves.

[0028] The heat pump system 100 further includes a coolant circuit 180, a nine-way valve 170, and a three-way valve HCTV. The coolant circuit 180 includes a second heat exchanger 113, and both ends of the coolant circuit 180 are respectively connected to two different ports of the nine-way valve 170. The passenger compartment circuit 140 can be connected to the coolant circuit 180 through the nine-way valve 170 and the three-way valve HCTV. Both ends of the battery circuit 150 and both ends of the electric drive circuit 160 are respectively connected to two different ports of the nine-way valve 170.

[0029] The present application provides a low temperature control method for the heat pump system 100 . Figure 2 A flow chart of a low temperature control method for a heat pump system according to an embodiment of the present application is disclosed. Figure 2 As shown, a low temperature control method of a heat pump system according to an embodiment of the present application may include steps S201 to S205.

[0030] In step S201, the vehicle is powered on.

[0031] In step S202, after the vehicle is powered on, the electric drive outlet water temperature Tout of the electric drive circuit is obtained.

[0032] In step S203, when the outlet water temperature Tout of the electric drive is lower than a first predetermined temperature threshold, control is performed to start active heating of the electric drive.

[0033] In step S204 , when a passenger compartment heating request is received, the intake port pressure Pin of the compressor 111 is acquired.

[0034] In step S205, when the suction port pressure Pin is lower than the predetermined pressure threshold, the control enters the compressor pulse start mode. The compressor pulse start mode is that the compressor 111 runs at a predetermined low speed for a first period of time, and then stops and waits for a second period of time to start.

[0035] The low-temperature control method of the heat pump system of the present application can quickly increase the temperature of the refrigerant in the heat pump system, so that the low pressure can be quickly increased to the pressure requirement for continuous operation, thereby entering the normal heat pump mode more quickly and meeting customer heating needs.

[0036] The low temperature control method of the heat pump system of the present application can expand the heat pump operating temperature to -30°C through electric drive active heating and compressor pulse start mode.

[0037] In some embodiments, the low temperature control method of the heat pump system of the present application may further include step S206.

[0038] In step S206 , in the compressor pulse start mode, the first throttle valve BEXV is controlled to start, and the second throttle valve AEXV and the third throttle valve EEXV are controlled to close.

[0039] Optionally, in order to reduce the impact and pressure fluctuation during startup, the first throttle valve BEXV may be controlled to soft-start, and the fluid flow rate may be gradually increased by gradually adjusting the opening of the first throttle valve BEXV.

[0040] Combine the following Figure 3 A specific process of the low temperature control method of the heat pump system of the present application is introduced in detail.

[0041] Figure 3 A specific flow chart of the low temperature control method of the heat pump system of the present application is disclosed. Figure 3 As shown, in step S301, the vehicle is powered on. In step S302, after the vehicle is powered on, the electric drive outlet water temperature Tout is determined. In step S303, when the electric drive outlet water temperature Tout is lower than the first predetermined temperature threshold, for example: Tout≤-15°C, the electric drive active heating is controlled to be started. In step S304, when the electric drive outlet water temperature Tout is higher than the second predetermined temperature threshold, for example: Tout≥0°C, the electric drive active heating is controlled to be turned off. At the same time, in step S305, when the electric drive outlet water temperature Tout is not lower than the third predetermined temperature threshold, for example: Tout≥-18°C, the determination of entering the heat pump condition can be controlled.

[0042] In step S306, there is a request for heating in the passenger compartment. When there is a request for heating in the passenger compartment, the process proceeds to step S307. In step S307, the compressor low pressure is determined, that is, the suction port pressure Pin of the compressor 111 is determined. At an ambient temperature of -30°C, the starting low pressure of the suction port of the compressor 111 is about 0.85 bar. When the suction port pressure Pin of the compressor 111 is lower than the predetermined pressure threshold, for example: 0.85 bar<Pin<0.9 bar, the process proceeds to step S308. In step S308, it is determined whether it is the first start. If it is the first start, the process directly proceeds to step S309. In step S309, the compressor pulse start mode is entered, that is, the compressor 111 is controlled to run at a predetermined low speed for a first time, and then stop and wait for a second time to start, for example: the compressor 111 is controlled to run at 850 rpm (revolutions / minute) for 5s (seconds), then stop, wait for 5s and then start again.

[0043] In order to better protect the compressor 111, the number of pulse starts of the compressor 111 can be limited. In some embodiments, the low temperature control method of the heat pump system of the present application can also include: in the compressor pulse start mode, the compressor 111 is controlled to run at a predetermined low speed for a first predetermined time, and then stopped to wait for a second predetermined time for a maximum of N predetermined times, for example, N = 5.

[0044] In some embodiments, the low temperature control method of the heat pump system of the present application may also include: after the compressor 111 pulse starts for a predetermined number of times N, when the suction port pressure Pin of the compressor 111 is still lower than the predetermined pressure threshold, the state of the suction port pressure Pin lower than the predetermined pressure threshold is maintained for more than the third predetermined time, and the compressor pulse start mode in step S309 can be controlled. Therefore, in step S308, if it is not the first start, it is necessary to further determine whether the low pressure is too low for more than the third predetermined time, and the third predetermined time can be, for example, 1h (hour). That is to say, after the compressor pulse start is repeated for example 5 times, when the suction port pressure Pin of the compressor 111 is still too low (lower than the predetermined pressure threshold, for example <0.9bar), it is necessary to meet the low pressure too low for more than 1h before the process can enter the compressor pulse start mode in step S309. Thereby, it is possible to prevent the compressor 111 from being damaged by the compressor 111 due to the excessively frequent start.

[0045] When the result of the judgment in step S308 is that the condition of "first start, or low pressure is maintained for more than 1 hour" is not satisfied, the process proceeds to step S311. In step S311, the compressor 111 is controlled to stop.

[0046] Figure 4The heat pump system of one embodiment of the present application is disclosed in the structural schematic diagram of the electric drive active heating and compressor pulse start mode. Figure 4 As shown, when the electric drive outlet water temperature Tout is too low, the electric drive can be actively heated to increase the electric drive outlet water temperature Tout. In the compressor pulse start mode, the first throttle valve BEXV is controlled to soft start, the second throttle valve AEXV and the third throttle valve EEXV are closed, and the compressor 111 is started at a low speed.

[0047] In some embodiments, the low-temperature control method of the heat pump system of the present application may also include: during the operation of the compressor pulse start mode, continuously obtaining the suction port pressure Pin of the compressor 111; when the suction port pressure Pin is not lower than a predetermined pressure threshold, controlling the determination of entering the heat pump condition; when the heat pump condition is met, controlling entering the heat pump mode.

[0048] Return to reference Figure 3 As shown, in step S307, the low pressure of the compressor 111 is continuously judged during the operation of the compressor pulse start mode. When the suction port pressure Pin of the compressor 111 is not lower than the predetermined pressure threshold, for example: Pin≥0.9bar, the step S305 can be entered to determine the heat pump condition. When the suction port pressure Pin of the compressor 111 is in the range of 0.9bar-1.1bar, that is, 0.9bar≤Pin<1.1bar, and the operation is less than the fourth predetermined time, or the suction port pressure Pin is not lower than 1.1bar, that is, Pin≥1.1bar, it is determined that the heat pump condition is met, and the process enters step S310. In step S310, the control enters the heat pump mode.

[0049] Figure 5 The structure diagram of a heat pump system in heat pump mode according to an embodiment of the present application is disclosed. Figure 5 As shown, in the heat pump mode, the first throttle valve BEXV and the second throttle valve AEXV are controlled to soft start, the compressor 111 is controlled to soft start, and the opening or closing of the third throttle valve EEXV is controlled based on the evaporator anti-liquid accumulation logic.

[0050] For the refrigerant circuit 110: the low-temperature and low-pressure gaseous refrigerant becomes a high-pressure and high-temperature gaseous refrigerant after the compressor 111 does work, and after the first heat exchanger 112 as a condenser releases heat, the heat is exchanged to the passenger compartment circuit 140, and becomes a high-pressure and high-temperature liquid refrigerant, and then after throttling by the first throttle valve BEXV, it becomes a low-temperature and low-pressure refrigerant, and then passes through the second heat exchanger 113 as a cooler to absorb heat, absorb the heat of the battery circuit 150, and become a low-temperature and low-pressure gaseous refrigerant, and enter the compressor 111 for the next cycle. For the passenger compartment circuit 140: the high-temperature hot water flowing through the first heat exchanger 112 as a condenser flows through the three-way valve HCTV, and then passes through the air conditioning box heat exchanger Hex for heat exchange, and releases heat to the passenger compartment. The low-temperature water that releases heat passes through the warm air water pump HCWP, and then passes through the first heat exchanger 112 as a condenser again for the next cycle. For the electric drive circuit 160: the low-temperature cold water flowing through the second heat exchanger 113 as a cooler passes through the nine-way valve 170, then passes through the electric drive to absorb heat, then passes through the nine-way valve 170, and finally flows back to the second heat exchanger 113 as a cooler to release heat. Thus, the waste heat of the electric drive is transferred to the refrigerant circuit 110, and then transferred to the passenger compartment circuit 140 through the refrigerant circuit 110, so that the passenger compartment can be supplemented with heat.

[0051] In some embodiments, the low temperature control method of the heat pump system of the present application may also include: when the suction port pressure Pin is in the range of 0.9bar-1.1bar, that is, 0.9bar≤Pin<1.1bar and the operation exceeds the fifth predetermined time, then entering step S311, controlling the compressor 111 to stop.

[0052] When the compressor 111 is stopped, if there is a heating request for the passenger compartment, the above logic judgment is repeated.

[0053] The low-temperature control method of the heat pump system of the present application cleverly utilizes the characteristic of the compressor 111 that can operate briefly at extremely low pressure through electric drive active heating and compressor pulse start mode, allowing the refrigerant to flow intermittently, thereby bringing the heat in the second heat exchanger serving as a cooler more fully into the heat pump system.

[0054] The low-temperature control method of the heat pump system of the present application uses electric drive active heating and compressor pulse start mode, without the need for an additional PTC heater. The electric drive active heating is started to increase the refrigerant temperature on the second heat exchanger side, and the heat pump system temperature is increased through the compressor pulse start mode. During the pulse start mode, as long as the low pressure reaches the low pressure requirement for continuous operation, the normal heat pump mode is immediately entered, so that the R134a heat pump system can be started and continuously and stably operated at an ambient temperature of -30°C or above.

[0055] The present application also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the low-temperature control method of the heat pump system described above are implemented.

[0056] The present application also provides a low temperature control system 600 of a heat pump system. Figure 6 A schematic block diagram of a low temperature control system 600 of a heat pump system according to an embodiment of the present application is disclosed. Figure 6 As shown, a low temperature control system 600 of a heat pump system of an embodiment of the present application includes a processor 601, an internal bus 602, a network interface 603, a memory 604, and a non-volatile memory 605, and may also include hardware required for other services. The processor 601 can read the corresponding computer program from the non-volatile memory 605 into the memory 604 and then run it to implement the steps of the low temperature control method of the heat pump system as described above. Of course, in addition to the software implementation, the present application does not exclude other implementation methods, such as logic devices or a combination of software and hardware, etc., that is to say, the execution subject of the following processing flow is not limited to each logic unit, but can also be hardware or logic components.

[0057] The low temperature control system 600 of the heat pump system of the present application can have similar beneficial technical effects as the low temperature control method of the heat pump system described above, so it will not be described in detail here.

[0058] The present application also provides a vehicle. The vehicle includes a heat pump system 100 and a low temperature control system 600 of the heat pump system as described above. The low temperature control system 600 can control the heat pump system 100 .

[0059] The low-temperature control method, system, storage medium and vehicle of the heat pump system provided in the embodiment of the present application are introduced in detail above. Specific examples are used herein to illustrate the low-temperature control method, system, storage medium and vehicle of the heat pump system in the embodiment of the present application. The description of the above embodiments is only used to help understand the core idea of ​​the present application and is not intended to limit the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the spirit and principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications should also fall within the scope of protection of the claims attached to the present application.

Claims

1. A low temperature control method for a heat pump system, characterized in that: The method comprises: After the vehicle is powered on, the water temperature at the electric drive outlet of the electric drive circuit is obtained; When the water temperature at the outlet of the electric drive is lower than a first predetermined temperature threshold, controlling to start active heating of the electric drive; When a passenger compartment heating request is received, obtaining a suction port pressure of the compressor; When the suction port pressure is lower than a predetermined pressure threshold, the control enters a compressor pulse start mode, wherein the compressor pulse start mode is started by running the compressor at a predetermined low speed for a first period of time and then stopping to wait for a second period of time.

2. The method according to claim 1, characterized in that The heat pump system includes a first throttle valve, a second throttle valve, a third throttle valve, a first heat exchanger, a second heat exchanger and a third heat exchanger, one end of the first throttle valve is connected to the exhaust port of the compressor through the first heat exchanger, the other end of the first throttle valve is connected to the intake port of the compressor through the second heat exchanger, the two ends of the second throttle valve are respectively connected to the intake port and the exhaust port of the compressor, one end of the third throttle valve is connected to the second heat exchanger, and the other end of the third throttle valve is connected to the intake port of the compressor through the third heat exchanger, and the method further includes: In the compressor pulse start mode, the first throttle valve is controlled to be started, and the second throttle valve and the third throttle valve are controlled to be closed.

3. The method according to claim 1, characterized in that Also includes: In the compressor pulse start mode, the compressor is controlled to run at a predetermined low speed for a first predetermined time, and then stops and waits for a second predetermined time, which is repeated a maximum of a predetermined number of times.

4. The method according to claim 3, characterized in that Also includes: After the compressor pulse starts for the predetermined number of times, if the suction port pressure of the compressor is still lower than the predetermined pressure threshold, the compressor pulse start mode is controlled to be entered after the state of the suction port pressure being lower than the predetermined pressure threshold is maintained for more than a third predetermined time period.

5. The method according to claim 1, characterized in that Also includes: During the operation of the compressor pulse start mode, continuously obtaining the suction port pressure of the compressor; When the air intake pressure is not lower than the predetermined pressure threshold, the control enters the determination of the heat pump condition; When the heat pump condition is met, the control enters the heat pump mode.

6. The method according to claim 5, characterized in that When the heat pump condition is met, the control enters the heat pump mode, including: When the air inlet pressure is in the range of 0.9 bar-1.1 bar and the operation time is less than the fourth predetermined time, or the air inlet pressure is not less than 1.1 bar, it is determined that the heat pump condition is met, and the control enters the heat pump mode; The method further comprises: When the suction port pressure is within the range of 0.9 bar-1.1 bar and the operation exceeds a fifth predetermined time, the compressor is controlled to stop.

7. The method according to claim 1, characterized in that Also includes: When the water temperature at the outlet of the electric drive is higher than a second predetermined temperature threshold, the electric drive active heating is controlled to be turned off; When the water temperature at the electric drive outlet is not lower than the third predetermined temperature threshold, the control enters the determination of the heat pump condition.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the low-temperature control method of the heat pump system according to any one of claims 1 to 7 are implemented.

9. A low temperature control system for a heat pump system, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the low temperature control method of the heat pump system as described in any one of claims 1 to 7 when executing the computer program.

10. A vehicle, characterized in that: A low-temperature control system comprising a heat pump system and a heat pump system as claimed in claim 9, wherein the heat pump system comprises a refrigerant circuit and an electric drive circuit, the refrigerant circuit comprises a first refrigerant circuit and a second refrigerant circuit, the first refrigerant circuit comprises a compressor, a first heat exchanger, a first throttle valve, a second heat exchanger and a second throttle valve, the exhaust port of the compressor is connected to the first end of the first heat exchanger, the second end of the first heat exchanger is connected to one end of the first throttle valve, the other end of the first throttle valve is connected to the intake port of the compressor through the second heat exchanger, the two ends of the second throttle valve are respectively connected to the intake port and the exhaust port of the compressor, the second refrigerant circuit comprises a third throttle valve and a third heat exchanger, one end of the third throttle valve is connected to the second end of the second heat exchanger, and the other end of the third throttle valve is connected to the intake port of the compressor through the third heat exchanger, and the low-temperature control system is used to control the heat pump system.

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