Low-temperature control method and device for heat pump system, and vehicle

Abstract

A low-temperature control method and device for a heat pump system, and a vehicle. A heat pump system comprises a heat pump circuit (10), the heat pump circuit (10) comprising a compressor (11) and a first throttling element (12), and two ends of the first throttling element (12) respectively being connected to an exhaust port and an intake port of the compressor (11). The method comprises: in response to a start instruction of the heat pump system, controlling the compressor (11) to work, and controlling the opening degree of the first throttling element (12) to adjust the intake pressure of the compressor (11) until there is a suction superheat at the intake port of the compressor (11); and gradually adjusting the rotating speed of the compressor (11), and controlling the opening degree of the first throttling element (12) to adjust the intake pressure of the compressor (11), so as to gradually adjust within a preset intake pressure range the rotating speed of the compressor (11) to a target rotating speed.

Description

Low temperature control method, device and vehicle for heat pump system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application No. 202311613947.5, filed on November 28, 2023, entitled “Low-temperature control method, device and vehicle for heat pump system,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of vehicle technology, and in particular to a low-temperature control method for a heat pump system, a low-temperature control device for a heat pump system, and a vehicle. Background Art

[0004] At present, the market share of new energy electric vehicles is gradually increasing. In order to improve the energy utilization rate of electric vehicles and reduce the power consumption of the entire vehicle, more and more electric vehicles are equipped with heat pump systems as standard.

[0005] To enable heat pump systems to operate at lower ambient temperatures, related technologies include using electric drive heating to increase heat output, and bypassing hot gas from the compressor to increase heat production. However, in low-temperature environments, cold starts often result in problems such as low suction pressure or excessively rapid compressor speed increases, which can damage the compressor.

[0006] Public content

[0007] The present disclosure aims to at least partially address one of the technical problems in the related art. To this end, a first object of the present disclosure is to provide a low-temperature control method for a heat pump system, which can control a first throttling element based on the suction pressure of the compressor, effectively preventing damage to the compressor due to excessively low suction pressure, and adjust the speed based on the compressor's suction pressure feedback, thereby preventing damage to the compressor due to excessively rapid speed increases, which can lead to vacuuming of the compressor.

[0008] A second object of the present disclosure is to provide a heat pump system.

[0009] A third objective of the present disclosure is to provide a low-temperature control device for a heat pump system.

[0010] A fourth object of the present disclosure is to provide a vehicle.

[0011] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present disclosure proposes a low-temperature control method for a heat pump system, wherein the heat pump system includes a heat pump circuit, and the heat pump circuit includes a compressor and a first throttling element, and the two ends of the first throttling element are respectively connected to the exhaust port and the intake port of the compressor. The method includes: responding to the start-up instruction of the heat pump system, controlling the operation of the compressor, and controlling the opening of the first throttling element to adjust the intake pressure of the compressor until there is intake superheat at the intake port of the compressor; gradually adjusting the speed of the compressor, and controlling the opening of the first throttling element to adjust the intake pressure of the compressor, so as to gradually adjust the speed of the compressor to the target speed within the preset intake pressure range.

[0012] According to the low-temperature control method of the heat pump system of the embodiment of the present disclosure, first, in response to the startup instruction of the heat pump system, the operation of the compressor is controlled, and the opening of the first throttling element is controlled to adjust the suction pressure of the compressor until the suction port of the compressor has suction superheat; then, the speed of the compressor is gradually adjusted, and the opening of the first throttling element is controlled to adjust the suction pressure of the compressor, so as to gradually adjust the speed of the compressor to the target speed within a preset suction pressure range. As a result, the method can control the first throttling element based on the suction pressure of the compressor, which can effectively avoid damage to the compressor caused by too low suction pressure, and adjust the speed based on the suction pressure feedback of the compressor, which can avoid damage to the compressor caused by the compressor vacuuming due to too rapid speed increase.

[0013] In addition, the low temperature control method of the heat pump system according to the above embodiment of the present disclosure may also have the following additional technical features:

[0014] According to one embodiment of the present disclosure, controlling the operation of the compressor and controlling the opening of the first throttling element to adjust the suction pressure of the compressor until suction superheat exists at the suction port of the compressor includes: controlling the compressor to operate at a first preset speed, controlling the opening of the first throttling element to be the first preset opening, and obtaining the suction pressure of the compressor; when the suction pressure rises to the first preset suction pressure, reducing the opening of the first throttling element to reduce the suction pressure, and when the suction pressure decreases to a second preset suction pressure, maintaining the opening of the first throttling element unchanged until suction superheat exists at the suction port of the compressor; wherein, the first preset speed is less than the target speed, and the first preset suction pressure is greater than the second preset suction pressure.

[0015] According to one embodiment of the present disclosure, the method further includes: obtaining the suction temperature of the compressor and determining the saturation temperature corresponding to the suction pressure; obtaining the temperature difference between the suction temperature and the saturation temperature corresponding to the suction pressure; and determining that there is suction superheat at the suction port of the compressor when the temperature difference is greater than a preset temperature difference.

[0016] According to one embodiment of the present disclosure, the stepwise adjustment of the speed of the compressor and the control of the opening of the first throttling element to adjust the suction pressure of the compressor, so as to gradually adjust the speed of the compressor to a target speed within a preset suction pressure range, include: increasing the speed of the compressor according to a preset step size and obtaining the suction pressure of the compressor; when the suction pressure reaches the second preset suction pressure, keeping the speed of the compressor unchanged and increasing the opening of the first throttling element to increase the suction pressure; and when the suction pressure increases to the first preset suction pressure, keeping the opening of the first throttling element unchanged and returning to the step of increasing the speed of the compressor according to the preset step size, until the speed of the compressor is gradually adjusted to the target speed.

[0017] According to one embodiment of the present disclosure, the heat pump circuit further includes a first heat exchanger, a second heat exchanger and a second throttling element, wherein the first end of the first heat exchanger is connected to the exhaust port of the compressor, the second end of the first heat exchanger is connected to one end of the second throttling element, the other end of the second throttling element is connected to the first end of the second heat exchanger, and the second end of the second heat exchanger is connected to the intake port of the compressor, wherein, after gradually adjusting the speed of the compressor to the target speed, the method further includes: obtaining the intake superheat of the compressor; and controlling the opening of the second throttling element according to the intake superheat so that the intake superheat is within a preset intake superheat range.

[0018] According to one embodiment of the present disclosure, the opening of the second throttling element is controlled according to the intake superheat so that the intake superheat is within a preset intake superheat range, including: when the intake superheat is greater than a first preset superheat, increasing the opening of the second throttling element; when the intake superheat is less than a second preset superheat, reducing the opening of the second throttling element; wherein the first preset superheat is greater than the second preset superheat.

[0019] According to one embodiment of the present disclosure, after increasing or decreasing the opening of the second throttling element, the method further includes: obtaining the suction pressure of the compressor; and controlling the opening of the first throttling element according to the suction pressure so that the suction pressure is within the preset suction pressure range.

[0020] According to one embodiment of the present disclosure, controlling the opening of the first throttling element according to the intake pressure so that the intake pressure is within the preset intake pressure range includes: reducing the opening of the first throttling element when the intake pressure is greater than a first preset intake pressure; and increasing the opening of the first throttling element when the intake pressure is less than a second preset intake pressure; wherein the first preset intake pressure is greater than the second preset intake pressure.

[0021] To achieve the above-mentioned objectives, the second embodiment of the present disclosure proposes a heat pump system, comprising: a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, the low-temperature control method of the heat pump system mentioned above is implemented.

[0022] According to the heat pump system of the embodiment of the present disclosure, through the above-mentioned low-temperature control method of the heat pump system, the first throttling element can be controlled based on the suction pressure of the compressor, which can effectively avoid damage to the compressor caused by too low suction pressure, and the speed is adjusted based on the suction pressure feedback of the compressor, which can avoid damage to the compressor caused by vacuuming the compressor due to excessively rapid speed increase.

[0023] To achieve the above-mentioned objectives, an embodiment of the third aspect of the present disclosure proposes a low-temperature control device for a heat pump system, wherein the heat pump system includes a heat pump circuit, the heat pump circuit includes a compressor and a first throttling element, and the two ends of the first throttling element are respectively connected to the exhaust port and the intake port of the compressor. The device includes: a first control module, which is used to control the operation of the compressor in response to the start-up instruction of the heat pump system, and control the opening of the first throttling element to adjust the intake pressure of the compressor until the intake port of the compressor has intake superheat; a second control module, which is used to gradually adjust the speed of the compressor after the intake port of the compressor has intake superheat, and control the opening of the first throttling element to adjust the intake pressure of the compressor, so as to gradually adjust the speed of the compressor to the target speed within a preset intake pressure range.

[0024] According to the low-temperature control device of the heat pump system of the embodiment of the present disclosure, the first control module controls the operation of the compressor in response to the startup instruction of the heat pump system, and controls the opening of the first throttling element to adjust the suction pressure of the compressor until the suction port of the compressor has suction superheat; after the suction port of the compressor has suction superheat, the second control module gradually adjusts the speed of the compressor, and controls the opening of the first throttling element to adjust the suction pressure of the compressor, so as to gradually adjust the speed of the compressor to the target speed within the preset suction pressure range. As a result, the device can control the first throttling element based on the suction pressure of the compressor, which can effectively avoid damage to the compressor caused by too low suction pressure, and adjust the speed based on the suction pressure feedback of the compressor, which can avoid damage to the compressor caused by the compressor vacuuming due to too rapid speed increase.

[0025] To achieve the above objectives, a fourth embodiment of the present disclosure proposes a vehicle comprising the above heat pump system, or a low-temperature control device of the above heat pump system.

[0026] According to the vehicle of the embodiment of the present disclosure, the first throttling element can be controlled based on the suction pressure of the compressor through the above-mentioned heat pump system or the low-temperature control device of the heat pump system, which can effectively avoid damage to the compressor caused by too low suction pressure, and adjust the speed based on the suction pressure feedback of the compressor, which can avoid damage to the compressor caused by vacuuming the compressor due to excessively rapid speed increase.

[0027] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a flow chart of a low-temperature control method for a heat pump system according to an embodiment of the present disclosure;

[0029] FIG2 is a schematic structural diagram of a heat pump system according to an embodiment of the present disclosure;

[0030] FIG3 is a flow chart of a low-temperature control method for a heat pump system according to an embodiment of the present disclosure;

[0031] FIG4 is a block diagram of a heat pump system according to an embodiment of the present disclosure;

[0032] FIG5 is a block diagram of a low-temperature control device of a heat pump system according to an embodiment of the present disclosure;

[0033] FIG6 is a block diagram of a vehicle according to an embodiment of the present disclosure;

[0034] FIG7 is a block diagram of a vehicle according to another embodiment of the present disclosure.

[0035] Figure numerals: heat pump circuit 10; compressor 11; first throttling element 12; first heat exchanger 13; second heat exchanger 14; second throttling element 15; warm air circuit 30; nine-way valve 40; three-way valve; battery heat exchange circuit 60; electric drive heat exchange circuit 70; ambient heat exchange circuit 80; heat pump system 200; memory 210; processor 220; low-temperature control device 100 of the heat pump system; first control module 110; second control module 120; vehicle 300. DETAILED DESCRIPTION

[0036] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0037] The following describes a low-temperature control method for a heat pump system, a heat pump system, a low-temperature control device for a heat pump system, and a vehicle according to embodiments of the present disclosure with reference to the accompanying drawings.

[0038] FIG1 is a flow chart of a low-temperature control method for a heat pump system according to an embodiment of the present disclosure.

[0039] In some embodiments of the present disclosure, as shown in FIG2 , a heat pump system includes a heat pump circuit 10, which includes a compressor 11 and a first throttling element 12. The first throttling element 12 has two ends connected to the exhaust port and the intake port of the compressor 11, respectively. The first throttling element may be an expansion valve.

[0040] As shown in FIG1 , the low temperature control method of the heat pump system according to the embodiment of the present disclosure may include the following steps:

[0041] S1, in response to a start-up instruction of the heat pump system, controls the operation of the compressor and controls the opening of the first throttling element to adjust the suction pressure of the compressor until suction superheat exists at the suction port of the compressor.

[0042] S2 gradually adjusts the speed of the compressor and controls the opening of the first throttle element to adjust the suction pressure of the compressor, thereby gradually adjusting the speed of the compressor to a target speed within a preset suction pressure range. The preset suction pressure range can be calibrated based on actual conditions, for example, the preset suction pressure range can be 1.18 bar to 1.22 bar. The target speed is the speed of the compressor corresponding to the heating request of the heat pump system. For example, the controller of the heat pump system can obtain the target temperature of the water-cooled condenser based on the heating request, and then perform a PID calculation based on the target temperature and the current temperature of the water-cooled condenser to obtain the target speed of the compressor.

[0043] Specifically, in a low-temperature environment, upon receiving a start command, the heat pump system's controller controls the compressor to perform a cold start. At this point, the first throttling element is controlled to its maximum opening. At this point, there is essentially no available heat in the heat pump system and the environment, and the compressor's intake port is not superheated. Under these conditions, based on the compressor's preset intake pressure range, the controller controls the compressor to increase its speed, maintaining operation at a lower speed. Refrigerant in the compressor flows from the exhaust port through the first throttling element and enters the intake port. The refrigerant is heated by the compressor's own heat, gradually increasing the intake pressure. When the intake pressure is high, the opening of the first throttling element is appropriately reduced to lower the intake pressure until the compressor's intake port experiences intake superheat.

[0044] When the compressor's suction port is superheated and the compressor has not yet reached the target speed, the controller gradually increases the speed. When the compressor's suction pressure drops to a preset suction pressure range, the compressor speed is controlled to maintain the current speed and the first throttle element is controlled to increase its opening to gradually increase the suction pressure. When the suction pressure is high, the compressor speed is gradually increased. This cycle can be repeated to gradually adjust the compressor speed to the target speed within the preset suction pressure range.

[0045] Therefore, the method disclosed in the present invention can control the first throttling element based on the suction pressure of the compressor, which can effectively avoid damage to the compressor caused by too low suction pressure, and adjust the speed based on the suction pressure feedback of the compressor, which can avoid damage to the compressor caused by vacuuming the compressor due to excessively rapid speed increase.

[0046] In one embodiment of the present disclosure, when the heat pump system is applied to a vehicle, the method further includes: obtaining an ambient temperature and a vehicle standstill time; and when the ambient temperature is less than a preset temperature threshold and the vehicle standstill time is greater than a preset time, controlling the compressor to operate and controlling the opening of the first throttle element to adjust the compressor's suction pressure until suction superheat is achieved at the compressor's suction port. The preset temperature threshold and the preset time can be calibrated based on actual conditions. For example, the preset temperature threshold can be -10°C, and the preset time can be 6 hours.

[0047] Specifically, when the heat pump system is installed on a vehicle, as shown in Figure 2, the heat pump system also includes a warm air circuit 30, a battery heat exchange circuit 60, an electric drive heat exchange circuit 70 and an ambient heat exchange circuit 80. When the heat supply capacity is sufficient, it means that the current heat pump circuit 10 has enough heat to provide heat to the warm air circuit 30, so the remaining heat can be released to one or more of the battery heat exchange circuit 60, the electric drive heat exchange circuit 70 and the ambient heat exchange circuit 80; when the heat supply capacity is insufficient, the warm air circuit 30 or the heat pump circuit 10 can be controlled to absorb heat from at least one of the battery heat exchange circuit 60, the electric drive heat exchange circuit 70 and the ambient heat exchange circuit 80 to supply heat to the passenger compartment. That is, when the heating capacity is insufficient, it means that the heat pump circuit 10 currently does not have enough heat to provide heat to the warm air circuit 30. Therefore, heat can be released to the warm air circuit 30 through one or more of the battery heat exchange circuit 60, the electric drive heat exchange circuit 70, and the ambient heat exchange circuit 80, thereby increasing the heat of the refrigerant in the warm air circuit 30 and providing heat to the passenger compartment. Alternatively, heat can be released to the heat pump circuit 10 through one or more of the battery heat exchange circuit 60, the electric drive heat exchange circuit 70, and the ambient heat exchange circuit 80, thereby providing heat to the warm air circuit and providing heat to the passenger compartment. The heat pump system also includes a nine-way valve 40 and a three-way valve 50, which are connected to the battery heat exchange circuit 60, the electric drive heat exchange circuit 70 and the environmental heat exchange circuit 80 through the nine-way valve 40 and the three-way valve 50; by controlling the nine-way valve 40 and the three-way valve 50, the heat pump circuit 10 can be controlled to provide heat to the warm air circuit 30 to supplement heat for the passenger compartment, and the warm air circuit 30 can be controlled to absorb heat from the battery heat exchange circuit 60 or the electric drive heat exchange circuit 70, or to release heat to at least one of the battery heat exchange circuit 60, the electric drive heat exchange circuit 70 and the environmental heat exchange circuit 80.

[0048] Furthermore, when the ambient temperature is below -10°C and the vehicle has been stationary for more than 6 hours, there is essentially no available heat in the heat pump system's battery heat exchange circuit, electric drive heat exchange circuit, and ambient heat exchange circuit. Upon receiving a start command, the heat pump system's controller controls the compressor for a cold start. At this time, the first throttle element is also opened to its maximum degree, ensuring that the compressor's intake port does not experience overheating. Under these conditions, based on the compressor's preset intake pressure range, the controller increases the compressor speed, maintaining operation at a lower speed. The compressor's own heat heats the refrigerant, and when intake pressure is high, the opening of the first throttle element is appropriately reduced to lower the intake pressure until intake superheat is achieved.

[0049] According to one embodiment of the present disclosure, controlling the operation of a compressor and controlling the opening of a first throttle element to adjust the compressor's suction pressure until suction superheat is present at the compressor's suction port includes: controlling the compressor to operate at a first preset speed, controlling the opening of the first throttle element to the first preset opening, and obtaining the compressor's suction pressure; when the suction pressure increases to the first preset suction pressure, reducing the opening of the first throttle element to lower the suction pressure; and when the suction pressure decreases to a second preset suction pressure, maintaining the opening of the first throttle element unchanged until suction superheat is present at the compressor's suction port; wherein the first preset speed is less than a target speed, and the first preset suction pressure is greater than the second preset suction pressure. For example, the first preset speed may be 3000 rpm, the target speed may be 8000 rpm, the first preset suction pressure may be 1.35 bar, and the second preset suction pressure may be 1.22 bar; and the first preset opening may be a maximum opening.

[0050] Specifically, after receiving a start command, the heat pump system's controller controls the compressor to perform a cold start. At this point, the first throttle element is controlled to its maximum opening (i.e., a first preset opening). At this point, there is essentially no available heat in the heat pump system's battery heat exchange circuit, electric drive heat exchange circuit, and ambient heat exchange circuit, and the compressor's intake port is not overheated. Under these conditions, based on the compressor's preset intake pressure range, the controller controls the compressor to increase its speed to a first preset speed, maintaining the compressor's operation at the first preset speed and heating the refrigerant through the compressor's own heat. When the intake pressure rises to 1.35 bar (the first preset intake pressure), the opening of the first throttle element is reduced, reducing the amount of refrigerant flowing to the compressor's intake port, thereby lowering the intake pressure. When the intake pressure drops to 1.22 bar (the second preset intake pressure), the opening of the first throttle element is maintained unchanged. This cycle continues until the compressor's intake port experiences intake superheat.

[0051] According to one embodiment of the present disclosure, the method further includes: obtaining the suction temperature of the compressor and determining the saturation temperature corresponding to the suction pressure; obtaining the temperature difference between the suction temperature and the saturation temperature corresponding to the suction pressure; and determining that the suction port of the compressor has suction superheat when the temperature difference is greater than a preset temperature difference. The preset temperature difference may be calibrated according to actual conditions.

[0052] Specifically, the controller can obtain the compressor's suction temperature via a temperature sensor installed at the compressor's suction port, obtain the compressor's suction pressure via a pressure sensor installed at the compressor's suction port, and determine the saturation temperature corresponding to the suction pressure by looking up a table. It should be understood that the table looked up is a saturation temperature-pressure table, which refers to the pressure value corresponding to a refrigerant at its saturation temperature. The controller subtracts the suction temperature from the saturation temperature corresponding to the suction pressure to obtain a temperature difference, and compares the temperature difference with a preset temperature difference. If the temperature difference is greater than the preset temperature difference, it can be determined that the compressor's suction port has suction superheat.

[0053] According to one embodiment of the present disclosure, the speed of the compressor is gradually adjusted, and the opening of the first throttling element is controlled to adjust the suction pressure of the compressor, so as to gradually adjust the speed of the compressor to the target speed within the preset suction pressure range, including: increasing the speed of the compressor according to a preset step length, and obtaining the suction pressure of the compressor; when the suction pressure reaches the second preset suction pressure, keeping the speed of the compressor unchanged, and increasing the opening of the first throttling element to increase the suction pressure; and when the suction pressure increases to the first preset suction pressure, keeping the opening of the first throttling element unchanged, and returning to the step of increasing the speed of the compressor according to the preset step length, until the speed of the compressor is gradually adjusted to the target speed. The preset step length can be calibrated according to actual conditions. For example, the preset step length can be 50rpm / s

[0054] Specifically, when the compressor overheats, as the electric drive components operate, heat from the electric drive heat exchange circuit is transferred to the compressor, causing the compressor's suction pressure to increase. When the compressor's suction port experiences suction superheat, the controller controls the compressor to increase its speed from a first preset speed according to a preset step size. As the speed increases, the amount of refrigerant extracted by the compressor after suction increases, and the compressor's suction pressure gradually decreases. When the suction pressure drops to a second preset suction pressure, the compressor speed no longer increases, maintaining the current speed. The opening of the first throttle element is increased to increase the suction pressure until the suction pressure reaches the first preset suction pressure, at which point the opening of the first throttle element remains unchanged. The compressor speed is then controlled to increase from the first preset speed according to a preset step size. When the suction pressure reaches the second preset suction pressure, the compressor speed is maintained unchanged, the opening of the first throttle element is increased to increase the suction pressure, and when the suction pressure reaches the first preset suction pressure, the opening of the first throttle element remains unchanged. This cycle continues until the compressor speed is gradually adjusted to the target speed.

[0055] According to one embodiment of the present disclosure, as shown in FIG2 , the heat pump circuit 10 further includes a first heat exchanger 13, a second heat exchanger 14, and a second throttling element 15. The first end of the first heat exchanger 13 is connected to the exhaust port of the compressor 11, the second end of the first heat exchanger 13 is connected to one end of the second throttling element 15, the other end of the second throttling element 15 is connected to the first end of the second heat exchanger 14, and the second end of the second heat exchanger 14 is connected to the intake port of the compressor 11. After gradually adjusting the compressor speed to a target speed, the method further includes: obtaining the compressor's intake superheat; and controlling the opening of the second throttling element based on the intake superheat so that the intake superheat is within a preset intake superheat range. The preset intake superheat range can be calibrated based on actual conditions. The first heat exchanger can be a water-cooled condenser, and the second throttling element can be an expansion valve.

[0056] Specifically, after the compressor becomes overheated, the controller controls the second throttle element to open to a certain opening, and the compressor suction port also increases. After the compressor speed is gradually adjusted to the target speed through the aforementioned steps, the controller obtains the compressor suction superheat. When the suction superheat is higher than a preset suction superheat range, the controller increases the opening of the second throttle element to increase the suction pressure and reduce the suction superheat. When the suction superheat is lower than the preset suction superheat range, the controller decreases the opening of the second throttle element to reduce the suction pressure and increase the suction superheat, thereby ensuring that the suction superheat is within the preset suction superheat range.

[0057] According to one embodiment of the present disclosure, the opening of the second throttling element is controlled based on the intake air superheat to keep the intake air superheat within a preset intake air superheat range. The control includes: increasing the opening of the second throttling element when the intake air superheat is greater than a first preset superheat; and decreasing the opening of the second throttling element when the intake air superheat is less than a second preset superheat. The first preset superheat is greater than the second preset superheat. The first and second preset superheats can be calibrated based on actual conditions.

[0058] That is to say, when the intake superheat is greater than the first preset superheat, the controller can increase the opening of the second throttling element to increase the intake pressure to reduce the intake superheat; when the intake superheat is less than the second preset superheat, the controller can reduce the opening of the second throttling element to reduce the intake pressure to increase the intake superheat, so that the intake superheat is within the range from the second preset superheat to the first preset superheat.

[0059] According to one embodiment of the present disclosure, after increasing or decreasing the opening of the second throttling element, the method further includes: obtaining the suction pressure of the compressor; and controlling the opening of the first throttling element according to the suction pressure so that the suction pressure is within a preset suction pressure range.

[0060] Further, according to an embodiment of the present disclosure, the opening of the first throttling element is controlled according to the intake pressure so that the intake pressure is within a preset intake pressure range, including: when the intake pressure is greater than a first preset intake pressure, reducing the opening of the first throttling element; when the intake pressure is less than a second preset intake pressure, increasing the opening of the first throttling element; wherein the first preset intake pressure is greater than the second preset intake pressure.

[0061] Specifically, when the intake superheat is greater than a first preset superheat, the controller may increase the opening of the second throttle element, thereby increasing the intake pressure. If the intake pressure is greater than the first preset intake pressure, the controller may decrease the opening of the first throttle element to decrease the intake pressure. If the intake pressure is less than the second preset intake pressure, the controller may increase the opening of the first throttle element to increase the intake pressure. Similarly, when the intake superheat is less than the second preset superheat, the controller may decrease the opening of the second throttle element to decrease the intake pressure. If the intake pressure is less than the second preset intake pressure, the controller may increase the opening of the first throttle element to increase the intake pressure. If the intake pressure is greater than the first preset intake pressure, the controller may decrease the opening of the first throttle element to decrease the intake pressure. When the intake pressure is within the preset intake pressure range, the controller may maintain the opening of the first throttle element unchanged.

[0062] The low-temperature control method of the heat pump system disclosed in the present invention will be described below with reference to FIG3 .

[0063] As a specific example, as shown in FIG3 , the low temperature control method of the heat pump system of the present disclosure may include the following steps:

[0064] S101 , in response to a start-up instruction of a heat pump system, controlling a compressor to operate at a first preset speed.

[0065] S102: Control the opening of the first throttling element to be a first preset opening.

[0066] S103: Obtain the suction pressure of the compressor.

[0067] S104: Determine whether the suction pressure has increased to a first preset suction pressure. If yes, proceed to step S105; if no, proceed to step S106.

[0068] S105: Reduce the opening of the first throttle element to reduce the intake pressure.

[0069] S106: Maintain the opening of the first throttling element unchanged.

[0070] S107: Determine whether the suction pressure has dropped to the second preset suction pressure. If yes, proceed to step S108; if not, return to step S107.

[0071] S108: Maintain the opening of the first throttling element unchanged until the suction port of the compressor has suction superheat.

[0072] S109: Increase the speed of the compressor according to a preset step size.

[0073] S110: Obtain the suction pressure of the compressor.

[0074] S111, determining whether the suction pressure reaches the second preset suction pressure. If yes, proceed to step S112; if no, return to step S109.

[0075] S112: Keep the speed of the compressor unchanged and increase the opening of the first throttling element to increase the suction pressure.

[0076] S113, determining whether the suction pressure reaches the first preset suction pressure. If yes, proceed to step S114; if no, return to step S113.

[0077] S114: Keep the opening of the first throttling element unchanged.

[0078] S115: Determine whether the speed of the compressor has been adjusted to the target speed. If yes, proceed to step S116; if not, return to step S109.

[0079] S116, stop adjusting the speed of the compressor.

[0080] S117: Determine whether the suction air superheat is greater than a first preset superheat. If yes, execute step S118; if not, execute step S124.

[0081] S118, increasing the opening of the second throttling element.

[0082] S119, obtaining the suction pressure of the compressor.

[0083] S120, determining whether the suction pressure is greater than a first preset suction pressure. If yes, proceed to step S121; if no, return to step S120.

[0084] S121, reducing the opening of the first throttling element.

[0085] S122, determining whether the suction pressure is less than a second preset suction pressure. If yes, proceed to step S123; if not, return to step S122.

[0086] S123, increasing the opening of the first throttle element.

[0087] S124: Determine whether the suction air superheat is less than a second preset superheat. If yes, proceed to step S125; if not, return to step S124.

[0088] S125, reduce the opening of the second throttling element, and return to step S119.

[0089] In summary, according to the low-temperature control method of the heat pump system of the embodiment of the present disclosure, first, in response to the start-up instruction of the heat pump system, the operation of the compressor is controlled, and the opening of the first throttling element is controlled to adjust the suction pressure of the compressor until there is suction superheat at the suction port of the compressor; then, the speed of the compressor is gradually adjusted, and the opening of the first throttling element is controlled to adjust the suction pressure of the compressor, so as to gradually adjust the speed of the compressor to the target speed within the preset suction pressure range. As a result, the method can control the first throttling element based on the suction pressure of the compressor, which can effectively avoid damage to the compressor caused by too low suction pressure, and adjust the speed based on the suction pressure feedback of the compressor, which can avoid damage to the compressor caused by the compressor vacuuming due to too rapid speed increase.

[0090] Corresponding to the above embodiments, the present disclosure also proposes a heat pump system.

[0091] FIG4 is a block diagram of a heat pump system according to an embodiment of the present disclosure.

[0092] As shown in FIG4 , the heat pump system 200 of the embodiment of the present disclosure includes: a memory 210, a processor 220, and a program stored in the memory 210 and executable on the processor 220. When the processor 210 executes the program, the low-temperature control method of the heat pump system described above is implemented.

[0093] According to the heat pump system of the embodiment of the present disclosure, through the above-mentioned low-temperature control method of the heat pump system, the first throttling element can be controlled based on the suction pressure of the compressor, which can effectively avoid damage to the compressor caused by too low suction pressure, and the speed is adjusted based on the suction pressure feedback of the compressor, which can avoid damage to the compressor caused by vacuuming the compressor due to excessively rapid speed increase.

[0094] Corresponding to the above embodiment, the present disclosure also proposes a low-temperature control device for a heat pump system.

[0095] FIG5 is a block diagram of a low-temperature control device of a heat pump system according to an embodiment of the present disclosure.

[0096] As shown in Figure 5, the low-temperature control device 100 of the heat pump system of the embodiment of the present disclosure includes a heat pump system including a heat pump circuit, the heat pump circuit including a compressor and a first throttling element, the two ends of the first throttling element are respectively connected to the exhaust port and the intake port of the compressor, and the device 100 may include: a first control module 110 and a second control module 120.

[0097] The first control module 110 is configured to respond to a startup command of the heat pump system, control the operation of the compressor, and control the opening of the first throttle element to adjust the compressor's suction pressure until suction superheat is achieved at the compressor's suction port. The second control module 120 is configured to gradually adjust the compressor's speed after suction superheat is achieved at the compressor's suction port, and control the opening of the first throttle element to adjust the compressor's suction pressure, thereby gradually adjusting the compressor's speed to a target speed within a preset suction pressure range.

[0098] According to one embodiment of the present disclosure, the first control module 110 controls the operation of the compressor and controls the opening of the first throttling element to adjust the suction pressure of the compressor until suction superheat exists at the suction port of the compressor. Specifically, it is used to control the compressor to operate at a first preset speed, control the opening of the first throttling element to be the first preset opening, and obtain the suction pressure of the compressor; when the suction pressure rises to the first preset suction pressure, reduce the opening of the first throttling element to reduce the suction pressure, and when the suction pressure drops to the second preset suction pressure, keep the opening of the first throttling element unchanged until suction superheat exists at the suction port of the compressor; wherein, the first preset speed is less than the target speed, and the first preset suction pressure is greater than the second preset suction pressure.

[0099] According to one embodiment of the present disclosure, the first control module 110 is further used to obtain the suction temperature of the compressor and determine the saturation temperature corresponding to the suction pressure; obtain the temperature difference between the suction temperature and the saturation temperature corresponding to the suction pressure; and when the temperature difference is greater than a preset temperature difference, determine that there is suction superheat at the suction port of the compressor.

[0100] According to one embodiment of the present disclosure, the second control module 120 gradually adjusts the speed of the compressor and controls the opening of the first throttling element to adjust the suction pressure of the compressor, so as to gradually adjust the speed of the compressor to the target speed within a preset suction pressure range. Specifically, it is used to increase the speed of the compressor according to a preset step size and obtain the suction pressure of the compressor; when the suction pressure reaches the second preset suction pressure, the speed of the compressor is kept unchanged, and the opening of the first throttling element is increased to increase the suction pressure; and when the suction pressure increases to the first preset suction pressure, the opening of the first throttling element is kept unchanged, and the step of increasing the speed of the compressor according to the preset step size is returned until the speed of the compressor is gradually adjusted to the target speed.

[0101] According to one embodiment of the present disclosure, the heat pump circuit also includes a first heat exchanger, a second heat exchanger and a second throttling element, the first end of the first heat exchanger is connected to the exhaust port of the compressor, the second end of the first heat exchanger is connected to one end of the second throttling element, the other end of the second throttling element is connected to the first end of the second heat exchanger, and the second end of the second heat exchanger is connected to the intake port of the compressor, wherein, after gradually adjusting the speed of the compressor to the target speed, the second control module 120 is also used to obtain the intake superheat of the compressor; and control the opening of the second throttling element according to the intake superheat so that the intake superheat is within a preset intake superheat range.

[0102] According to one embodiment of the present disclosure, the second control module 120 controls the opening of the second throttling element according to the intake superheat so that the intake superheat is within a preset intake superheat range. Specifically, when the intake superheat is greater than a first preset superheat, the opening of the second throttling element is increased; when the intake superheat is less than a second preset superheat, the opening of the second throttling element is decreased; wherein the first preset superheat is greater than the second preset superheat.

[0103] According to one embodiment of the present disclosure, after increasing or decreasing the opening of the second throttling element, the second control module 120 is further used to obtain the suction pressure of the compressor; and control the opening of the first throttling element according to the suction pressure so that the suction pressure is within a preset suction pressure range.

[0104] According to one embodiment of the present disclosure, the second control module 120 controls the opening of the first throttling element according to the intake pressure so that the intake pressure is within a preset intake pressure range. Specifically, when the intake pressure is greater than the first preset intake pressure, the second control module 120 controls the opening of the first throttling element; when the intake pressure is less than the second preset intake pressure, the second control module 120 controls the opening of the first throttling element; wherein the first preset intake pressure is greater than the second preset intake pressure.

[0105] It should be noted that for details not disclosed in the low-temperature control device of the heat pump system in the embodiment of the present disclosure, please refer to the details disclosed in the low-temperature control method of the heat pump system in the embodiment of the present disclosure, and the details will not be repeated here.

[0106] According to the low-temperature control device of the heat pump system of the embodiment of the present disclosure, the first control module controls the operation of the compressor in response to the startup instruction of the heat pump system, and controls the opening of the first throttling element to adjust the suction pressure of the compressor until the suction port of the compressor has suction superheat; after the suction port of the compressor has suction superheat, the second control module gradually adjusts the speed of the compressor, and controls the opening of the first throttling element to adjust the suction pressure of the compressor, so as to gradually adjust the speed of the compressor to the target speed within the preset suction pressure range. As a result, the device can control the first throttling element based on the suction pressure of the compressor, which can effectively avoid damage to the compressor caused by too low suction pressure, and adjust the speed based on the suction pressure feedback of the compressor, which can avoid damage to the compressor caused by the compressor vacuuming due to too rapid speed increase.

[0107] Corresponding to the above embodiments, the present disclosure also proposes a vehicle.

[0108] As shown in FIG6 , the vehicle 300 according to the embodiment of the present disclosure may include the heat pump system 200 described above. Alternatively, as shown in FIG7 , the vehicle 300 according to the embodiment of the present disclosure may further include the low temperature control device 100 of the heat pump system described above.

[0109] According to the vehicle of the embodiment of the present disclosure, the first throttling element can be controlled based on the suction pressure of the compressor through the above-mentioned heat pump system or the low-temperature control device of the heat pump system, which can effectively avoid damage to the compressor caused by too low suction pressure, and adjust the speed based on the suction pressure feedback of the compressor, which can avoid damage to the compressor caused by vacuuming the compressor due to excessively rapid speed increase.

[0110] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0111] It should be understood that various parts of the present disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0112] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0113] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0114] In this disclosure, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components, unless otherwise expressly limited. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on specific circumstances.

[0115] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A low-temperature control method for a heat pump system, the heat pump system including a heat pump circuit, the heat pump circuit including a compressor and a first throttling element, two ends of the first throttling element being correspondingly connected to an exhaust port and a suction port of the compressor respectively, the method comprises: responding to a start instruction of the heat pump system, controlling the compressor to operate, and performing opening degree control on the first throttling element to adjust the suction pressure of the compressor until there is suction superheat at the suction port of the compressor; gradually adjusting the rotational speed of the compressor, and performing opening degree control on the first throttling element to adjust the suction pressure of the compressor, so as to gradually adjust the rotational speed of the compressor to a target rotational speed within a preset suction pressure range.

2. The method according to claim 1, wherein, the controlling the compressor to operate, and performing opening degree control on the first throttling element to adjust the suction pressure of the compressor until there is suction superheat at the suction port of the compressor, comprises: controlling the compressor to operate at a first preset rotational speed, controlling the opening degree of the first throttling element to be a first preset opening degree, and obtaining the suction pressure of the compressor; when the suction pressure rises to a first preset suction pressure, reducing the opening degree of the first throttling element to lower the suction pressure, and when the suction pressure drops to a second preset suction pressure, keeping the opening degree of the first throttling element unchanged until there is suction superheat at the suction port of the compressor; wherein the first preset rotational speed is less than the target rotational speed, and the first preset suction pressure is greater than the second preset suction pressure.

3. The method according to claim 2, wherein, the method further comprises: obtaining the suction temperature of the compressor, and determining the saturation temperature corresponding to the suction pressure; obtaining the temperature difference between the suction temperature and the saturation temperature corresponding to the suction pressure; when the temperature difference is greater than a preset temperature difference, determining that there is suction superheat at the suction port of the compressor.

4. The method according to claim 2, wherein, the gradually adjusting the rotational speed of the compressor, and performing opening degree control on the first throttling element to adjust the suction pressure of the compressor, so as to gradually adjust the rotational speed of the compressor to a target rotational speed within a preset suction pressure range, comprises: raising the rotational speed of the compressor according to a preset step size, and obtaining the suction pressure of the compressor; when the suction pressure reaches the second preset suction pressure, keeping the rotational speed of the compressor unchanged, increasing the opening degree of the first throttling element to raise the suction pressure, and when the suction pressure rises to the first preset suction pressure, keeping the opening degree of the first throttling element unchanged, and returning to the step of raising the rotational speed of the compressor according to the preset step size until the rotational speed of the compressor is gradually adjusted to the target rotational speed.

5. The method according to any one of claims 1-4, wherein, The heat pump circuit further includes a first heat exchanger, a second heat exchanger, and a second throttling element. A first end of the first heat exchanger is connected to an exhaust port of the compressor, a second end of the first heat exchanger is connected to one end of the second throttling element, the other end of the second throttling element is connected to a first end of the second heat exchanger, and a second end of the second heat exchanger is connected to a suction port of the compressor. Wherein, after gradually adjusting the rotational speed of the compressor to a target rotational speed, the method further includes: Obtaining the suction superheat degree of the compressor; Controlling the opening degree of the second throttling element according to the suction superheat degree so that the suction superheat degree is within a preset suction superheat degree range.

6. The method according to claim 5, wherein, The controlling the opening degree of the second throttling element according to the suction superheat degree so that the suction superheat degree is within a preset suction superheat degree range includes: When the suction superheat degree is greater than a first preset superheat degree, increasing the opening degree of the second throttling element; When the suction superheat degree is less than a second preset superheat degree, decreasing the opening degree of the second throttling element; wherein, the first preset superheat degree is greater than the second preset superheat degree.

7. The method according to claim 6, wherein, After increasing or decreasing the opening degree of the second throttling element, the method further includes: Obtaining the suction pressure of the compressor; Controlling the opening degree of the first throttling element according to the suction pressure so that the suction pressure is within the preset suction pressure range.

8. The method according to claim 7, wherein, The controlling the opening degree of the first throttling element according to the suction pressure so that the suction pressure is within the preset suction pressure range includes: When the suction pressure is greater than a first preset suction pressure, decreasing the opening degree of the first throttling element; When the suction pressure is less than a second preset suction pressure, increasing the opening degree of the first throttling element; wherein, the first preset suction pressure is greater than the second preset suction pressure.

9. A low-temperature control device for a heat pump system, the heat pump system includes a heat pump circuit, the heat pump circuit includes a compressor and a first throttling element, and two ends of the first throttling element are respectively and correspondingly connected to an exhaust port and a suction port of the compressor, the device includes: A first control module, configured to respond to a start instruction of the heat pump system, control the compressor to operate, and control the opening degree of the first throttling element to adjust the suction pressure of the compressor until there is suction superheat degree at the suction port of the compressor; A second control module, configured to gradually adjust the rotational speed of the compressor after there is suction superheat degree at the suction port of the compressor, and control the opening degree of the first throttling element to adjust the suction pressure of the compressor, so as to gradually adjust the rotational speed of the compressor to a target rotational speed within a preset suction pressure range.

10. A vehicle, including the low-temperature control device of the heat pump system according to claim 9.

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