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

Abstract

The application discloses a low-temperature control method and device of a heat pump system and a vehicle, and the heat pump system comprises a heat pump circuit, the heat pump circuit comprises a compressor and a first throttling element, two ends of the first throttling element are connected with a discharge port and a suction port of the compressor respectively, and the method comprises the following steps: in response to a starting instruction of the heat pump system, the compressor is controlled to work, and the opening degree 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; the rotating speed of the compressor is adjusted gradually, and the opening degree of the first throttilling element is controlled to adjust the suction pressure of the compressor, so that the rotating speed of the compressor is adjusted gradually to a target rotating speed in a preset suction pressure range. The method can effectively avoid damage of the compressor caused by too low suction pressure, and can avoid damage of the compressor caused by too fast rotating speed of the compressor.

Description

Technical Field

[0001] This invention 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 Technology

[0002] Currently, 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 overall power consumption, more and more electric vehicles are equipped with heat pump systems as standard.

[0003] In related technologies, to enable heat pump systems to operate at lower ambient temperatures, the electric drive unit's heating technology increases the heat output of the heat pump system, and the compressor's hot gas bypass increases the compressor's heat production. However, in low-temperature environments, problems such as excessively low suction pressure or excessively rapid compressor speed increase often occur during the compressor's cold start process, leading to compressor damage. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in the related art. Therefore, the first objective of this invention is to propose a low-temperature control method for a heat pump system, which can control the first throttling element based on the compressor's suction pressure, effectively preventing damage to the compressor caused by excessively low suction pressure. Furthermore, by adjusting the compressor's rotational speed based on suction pressure feedback, it can prevent damage caused by excessively rapid compressor speed increases leading to vacuuming.

[0005] The second objective of this invention is to provide a heat pump system.

[0006] The third objective of this invention is to provide a cryogenic control device for a heat pump system.

[0007] The fourth objective of this invention is to provide a vehicle.

[0008] To achieve the above objectives, a first aspect of the present invention provides a low-temperature control method for a heat pump system. The heat pump system includes a heat pump circuit, which includes 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. The method includes: responding to a start command of the heat pump system, controlling the compressor to operate, and controlling the opening degree 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 degree of the first throttling element to adjust the intake pressure of the compressor, so as to gradually adjust the speed of the compressor to a target speed within a preset intake pressure range.

[0009] According to the low-temperature control method of the heat pump system of the present invention, in response to the start command of the heat pump system, the compressor is controlled to operate, and the opening degree 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 compressor speed is gradually adjusted, and the opening degree of the first throttling element is controlled to adjust the suction pressure of the compressor, so as to gradually adjust the compressor speed to the target speed within a preset suction pressure range. Therefore, this 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 excessively low suction pressure, and adjust the speed based on the suction pressure feedback, which can avoid damage to the compressor caused by vacuuming due to excessively rapid speed increase.

[0010] In addition, the low-temperature control method for the heat pump system according to the above embodiments of the present invention may also have the following additional technical features:

[0011] According to one embodiment of the present invention, controlling the operation of the compressor and adjusting the opening degree 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 degree of the first throttling element to a first preset opening degree, and acquiring the suction pressure of the compressor; when the suction pressure rises to the first preset suction pressure, reducing the opening degree 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 degree 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.

[0012] According to one embodiment of the present invention, 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.

[0013] According to one embodiment of the present invention, the step of gradually adjusting the compressor speed and controlling the opening degree of the first throttling element to adjust the compressor suction pressure, so as to gradually adjust the compressor speed to the target speed within a preset suction pressure range, includes: increasing the compressor speed by a preset step size and obtaining the compressor suction pressure; when the suction pressure reaches the second preset suction pressure, keeping the compressor speed constant and increasing the opening degree 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 degree of the first throttling element constant and returning to the step of increasing the compressor speed by a preset step size, until the compressor speed is gradually adjusted to the target speed.

[0014] According to one embodiment of the present invention, 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 the 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 the first end of the second heat exchanger, and a second end of the second heat exchanger is connected to the suction port of the compressor. After gradually adjusting the compressor speed to a target speed, the method further includes: obtaining the suction superheat of the compressor; and controlling the opening degree of the second throttling element based on the suction superheat to ensure that the suction superheat is within a preset suction superheat range.

[0015] According to one embodiment of the present invention, controlling the opening of the second throttling element based on the intake superheat to keep the intake superheat within a preset intake superheat range includes: increasing the opening of the second throttling element when the intake superheat is greater than a first preset superheat; and decreasing the opening of the second throttling element when the intake superheat is less than a second preset superheat; wherein the first preset superheat is greater than the second preset superheat.

[0016] According to one embodiment of the present invention, 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.

[0017] According to an embodiment of the present invention, controlling the opening of the first throttling element based on the inhalation pressure to make the inhalation pressure within the preset inhalation pressure range includes: reducing the opening of the first throttling element when the inhalation pressure is greater than a first preset inhalation pressure; and increasing the opening of the first throttling element when the inhalation pressure is less than a second preset inhalation pressure; wherein the first preset inhalation pressure is greater than the second preset inhalation pressure.

[0018] To achieve the above objectives, a second aspect of the present invention provides a heat pump system, comprising: a memory, a processor, and a program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the above-described low-temperature control method for the heat pump system.

[0019] According to the heat pump system of the present invention, the low temperature control method of the heat pump system described above can control the first throttling element based on the suction pressure of the compressor, which can effectively avoid damage to the compressor caused by excessively low suction pressure. Furthermore, the speed can be adjusted based on the suction pressure feedback of the compressor, which can prevent damage to the compressor caused by excessively rapid increase in speed leading to vacuuming.

[0020] To achieve the above objectives, a third aspect of the present invention provides a low-temperature control device for a heat pump system. The heat pump system includes a heat pump circuit, which includes 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. The device includes: a first control module, configured to control the compressor to operate in response to a start command of the heat pump system, and to control the opening degree 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; and a second control module, configured to gradually adjust the speed of the compressor after there is intake superheat at the intake port of the compressor, and to control the opening degree of the first throttling element to adjust the intake pressure of the compressor, so as to gradually adjust the speed of the compressor to a target speed within a preset intake pressure range.

[0021] According to an embodiment of the present invention, a cryogenic control device for a heat pump system includes a first control module that, in response to a start-up command of the heat pump system, controls the compressor to operate and controls the opening degree of a first throttling element to adjust the compressor's suction pressure until suction superheat exists at the compressor's suction port. After suction superheat exists at the compressor's suction port, a second control module gradually adjusts the compressor's speed and controls the opening degree of the first throttling element to adjust the compressor's suction pressure, thereby gradually adjusting the compressor's speed to the target speed within a preset suction pressure range. Thus, this device can control the first throttling element based on the compressor's suction pressure, effectively preventing damage to the compressor caused by excessively low suction pressure. Furthermore, by adjusting the compressor's speed based on suction pressure feedback, it can prevent damage caused by excessively rapid speed increases leading to compressor vacuum.

[0022] To achieve the above objectives, a fourth aspect of the present invention provides a vehicle including the above-described heat pump system, or a cryogenic control device for the above-described heat pump system.

[0023] According to the vehicle of the present invention, the first throttling element can be controlled based on the suction pressure of the compressor by means of the heat pump system or the low temperature control device of the heat pump system, which can effectively avoid damage to the compressor caused by excessively low suction pressure, and the speed can be adjusted based on the suction pressure feedback of the compressor to avoid damage caused by the compressor being vacuumed due to excessively rapid increase in speed.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] Figure 1 A flowchart of a low-temperature control method for a heat pump system according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of a heat pump system according to an embodiment of the present invention;

[0027] Figure 3 A flowchart of a low-temperature control method for a heat pump system according to an embodiment of the present invention;

[0028] Figure 4 This is a block diagram of a heat pump system according to an embodiment of the present invention;

[0029] Figure 5 This is a block diagram of a low-temperature control device for a heat pump system according to an embodiment of the present invention;

[0030] Figure 6 A schematic block diagram of a vehicle according to an embodiment of the present invention;

[0031] Figure 7 This is a block diagram of a vehicle according to another embodiment of the present invention.

[0032] Figure label:

[0033] Heat pump circuit 10; compressor 11; first throttling element 12; first heat exchanger 13; second heat exchanger 14; second throttling element 15;

[0034] Heating 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;

[0035] Heat pump system 200; memory 210; processor 220;

[0036] Low-temperature control device 100 for heat pump system; first control module 110; second control module 120;

[0037] Vehicle 300. Detailed Implementation

[0038] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0039] The following description, with reference to the accompanying drawings, illustrates the cryogenic control method, heat pump system, cryogenic control device, and vehicle for a heat pump system proposed in embodiments of the present invention.

[0040] Figure 1 This is a flowchart of a low-temperature control method for a heat pump system according to an embodiment of the present invention.

[0041] In some embodiments of the present invention, such as Figure 2 As shown, the heat pump system includes a heat pump circuit 10, which includes a compressor 11 and a first throttling element 12. The two ends of the first throttling element 12 are respectively connected to the exhaust port and the intake port of the compressor 11. The first throttling element can be an expansion valve.

[0042] like Figure 1 As shown, the low-temperature control method of the heat pump system in this embodiment of the invention may include the following steps:

[0043] S1, in response to the start command of the heat pump system, controls the compressor to work and controls the opening degree of the first throttling element to adjust the suction pressure of the compressor until there is suction superheat at the suction port of the compressor.

[0044] S2, gradually adjust the compressor speed and control the opening degree of the first throttling element to adjust the compressor's suction pressure, so as to gradually adjust the compressor speed to the target speed within the preset suction pressure range. The preset suction pressure range can be calibrated according to actual conditions; for example, the preset suction pressure range can be 1.18 bar - 1.22 bar. The target speed is the compressor speed corresponding to the heating request of the heat pump system. For example, the heat pump system controller can obtain the target temperature of the water-cooled condenser based on the heating request, and then perform PID calculations based on the target temperature of the water-cooled condenser and the current temperature to obtain the target compressor speed.

[0045] Specifically, in low-temperature environments, after receiving a start-up command, the heat pump system controller controls the compressor to perform a cold start. At this time, it controls the first throttling element to operate at its maximum opening. At this point, there is essentially no usable heat in the heat pump system and the environment, and there is no superheat at the compressor's suction port. Under these conditions, based on the compressor's preset suction pressure range, the controller controls the compressor to increase its speed, allowing it to maintain operation at a lower speed. The refrigerant in the compressor flows out from the discharge port and enters the suction port through the first throttling element. The refrigerant is heated by the compressor's own heat, gradually increasing the suction pressure. When the suction pressure is high, the opening of the first throttling element is appropriately reduced to lower the suction pressure until there is suction superheat at the compressor's suction port.

[0046] If superheating occurs at the compressor's suction port, and the compressor has not yet reached the target speed, the controller gradually increases the speed. When the compressor's suction pressure drops to the preset suction pressure range, the controller can stop increasing the compressor speed, maintain the current speed, and control the first throttling element to increase the opening to gradually increase the suction pressure. When the suction pressure is high, the compressor speed is gradually increased again. This cycle repeats, allowing the compressor speed to be gradually adjusted to the target speed within the preset suction pressure range.

[0047] Therefore, the method of the present invention can control the first throttling element based on the compressor's suction pressure, which can effectively avoid damage to the compressor caused by excessively low suction pressure. Furthermore, by adjusting the speed based on the compressor's suction pressure feedback, it can prevent damage to the compressor caused by excessively rapid speed increase leading to vacuuming.

[0048] In one embodiment of the present invention, when the heat pump system is applied to a vehicle, before controlling the compressor to operate and adjusting the opening degree of the first throttling element to adjust the compressor's suction pressure until suction superheat exists at the compressor's suction port, the method further includes: acquiring the ambient temperature and the vehicle's resting time; when the ambient temperature is lower than a preset temperature threshold and the resting time is greater than a preset time, controlling the compressor to operate and adjusting the opening degree of the first throttling element to adjust the compressor's suction pressure until suction superheat exists at the compressor's suction port. The preset temperature threshold and preset time can be calibrated according to actual conditions; for example, the preset temperature threshold can be -10°C and the preset time can be 6 hours.

[0049] Specifically, when this heat pump system is installed in a vehicle, such as Figure 2 As shown, the heat pump system also includes a heating 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 replenishment capacity is sufficient, it means that the current heat pump circuit 10 has enough heat to provide heat to the heating circuit 30. Therefore, 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 replenishment capacity is insufficient, the heating 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 replenish heat to the passenger compartment. In other words, when the heat replenishment capacity is insufficient, it means that the current heat pump circuit 10 does not have enough heat to provide heat to the heating circuit 30. Therefore, heat can be released to the heating 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, increasing the refrigerant temperature in the heating circuit 30 to replenish heat to the passenger compartment. The system can also release heat to the heat pump circuit 10 through one or more of the battery heat exchange circuit 60, electric drive heat exchange circuit 70, and ambient heat exchange circuit 80, and provide heat to the heating circuit to supplement the crew 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, electric drive heat exchange circuit 70, and ambient heat exchange circuit 80. By controlling the nine-way valve 40 and the three-way valve 50, the system can control the heat pump circuit 10 to provide heat to the heating circuit 30 to supplement the crew compartment, and control the heating circuit 30 to absorb heat from the battery heat exchange circuit 60 or the electric drive heat exchange circuit 70, or release heat to at least one of the battery heat exchange circuit 60, the electric drive heat exchange circuit 70, and the ambient heat exchange circuit 80.

[0050] Furthermore, when the ambient temperature is below -10℃ and the vehicle has been stationary for more than 6 hours, there is essentially no usable heat in the battery heat exchange circuit, electric drive heat exchange circuit, and ambient heat exchange circuit of the heat pump system. Upon receiving the start command, the heat pump system controller controls the compressor to perform a cold start, simultaneously controlling the first throttling element to its maximum opening, ensuring no superheat at the compressor's suction port. Under these conditions, based on the compressor's preset suction pressure range, the controller increases the compressor's speed, maintaining operation at a lower speed. The compressor's own heat is used to heat the refrigerant. When the suction pressure is high, the controller appropriately reduces the opening of the first throttling element to lower the suction pressure until superheat exists at the compressor's suction port.

[0051] According to one embodiment of the present invention, controlling the operation of a compressor and adjusting the suction pressure of the compressor by controlling the opening degree of a first throttling element until suction superheat exists at the compressor's suction port includes: controlling the compressor to operate at a first preset speed, controlling the opening degree of the first throttling element to a first preset opening degree, and acquiring the suction pressure of the compressor; when the suction pressure rises to the 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, maintaining the opening degree of the first throttling element unchanged until suction superheat exists at the compressor's suction port; 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. For example, the first preset speed can be 3000 rpm, the target speed can be 8000 rpm, the first preset suction pressure can be 1.35 bar, and the second preset suction pressure can be 1.22 bar; the first preset opening degree can be the maximum opening degree.

[0052] Specifically, after receiving the start command, the heat pump system controller controls the compressor to perform a cold start. At this time, it controls the first throttling element to operate at its maximum opening (i.e., the first preset opening). At this point, there is essentially no usable heat in the battery heat exchange circuit, electric drive heat exchange circuit, and ambient heat exchange circuit of the heat pump system, and there is no superheat at the compressor's suction port. Under these conditions, based on the compressor's preset suction pressure range, the controller controls the compressor to increase its speed to the first preset speed, maintaining the compressor at this speed and heating the refrigerant using the compressor's own heat. When the suction pressure rises to 1.35 bar (the first preset suction pressure), the opening of the first throttling element is reduced, decreasing the amount of refrigerant flowing to the compressor's suction port, thereby lowering the suction pressure. When the suction pressure drops to 1.22 bar (the second preset suction pressure), the opening of the first throttling element remains unchanged. This cycle continues until there is suction superheat at the compressor's suction port.

[0053] According to one embodiment of the present invention, 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. The preset temperature difference can be calibrated according to actual conditions.

[0054] Specifically, the controller obtains the compressor's suction temperature through a temperature sensor located at the compressor's suction port and its suction pressure through a pressure sensor located at the compressor's suction port. It then determines the saturation temperature corresponding to the suction pressure by looking up a table. It's important to understand that the table used for this lookup 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 value. This temperature difference value is compared with a preset temperature difference value. If the temperature difference value is greater than the preset temperature difference value, it can be determined that there is suction superheat at the compressor's suction port.

[0055] According to one embodiment of the present invention, the compressor speed is gradually adjusted, and the opening degree of the first throttling element is controlled to adjust the compressor's suction pressure, so as to gradually adjust the compressor speed to a target speed within a preset suction pressure range. This includes: increasing the compressor speed by a preset step size and obtaining the compressor's suction pressure; when the suction pressure reaches a second preset suction pressure, keeping the compressor speed constant and increasing the opening degree of the first throttling element to increase the suction pressure; and when the suction pressure rises to the first preset suction pressure, keeping the opening degree of the first throttling element constant and returning to the step of increasing the compressor speed by a preset step size, until the compressor speed is gradually adjusted to the target speed. The preset step size can be calibrated according to actual conditions; for example, the preset step size can be 50 rpm / s.

[0056] Specifically, during the process of compressor superheating, 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 rise. When suction superheat exists at the compressor's suction port, the controller controls the compressor to increase its speed from the first preset speed in preset steps. As the speed increases, the amount of refrigerant drawn from the suction port increases, and the compressor's suction pressure gradually decreases. When the suction pressure drops to the second preset suction pressure, the compressor speed stops increasing, maintaining the current speed, and the opening of the first throttling element is increased to raise the suction pressure until the suction pressure rises to the first preset suction pressure. At this point, the opening of the first throttling element remains unchanged, and the controller again controls the compressor to increase its speed from the first preset speed in preset steps. When the suction pressure reaches the second preset suction pressure, the controller maintains the compressor speed and increases the opening of the first throttling element to raise the suction pressure. This cycle continues until the compressor speed is gradually adjusted to the target speed.

[0057] According to one embodiment of the present invention, such as Figure 2 As shown, the heat pump circuit 10 also 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 suction port of the compressor 11. After gradually adjusting the compressor speed to the target speed, the method further includes: obtaining the compressor's suction superheat; and controlling the opening of the second throttling element based on the suction superheat to ensure that the suction superheat is within a preset suction superheat range. The preset suction superheat range can be calibrated according to actual conditions. The first heat exchanger can be a water-cooled condenser, and the second throttling element can be an expansion valve.

[0058] Specifically, after the compressor experiences superheat, the controller opens the second throttling element to a certain degree, increasing the pressure at the compressor's suction port. After gradually adjusting the compressor speed to the target speed through the aforementioned steps, the controller acquires the compressor's suction superheat. When the suction superheat exceeds a preset range, the controller increases the opening of the second throttling element to increase the suction pressure and reduce the suction superheat. When the suction superheat is below the preset range, the controller decreases the opening of the second throttling element to decrease the suction pressure and increase the suction superheat, thus keeping the suction superheat within the preset range.

[0059] According to one embodiment of the present invention, controlling the opening of a second throttling element based on the intake superheat to keep the intake superheat within a preset intake superheat range includes: increasing the opening of the second throttling element when the intake superheat is greater than a first preset superheat; and decreasing the opening of the second throttling element when the intake superheat is less than the second preset superheat; wherein the first preset superheat is greater than the second preset superheat. The first and second preset superheats can be calibrated according to actual conditions.

[0060] In other words, 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 and reduce the intake superheat; when the intake superheat is less than the second preset superheat, the controller can decrease the opening of the second throttling element to decrease the intake pressure and increase the intake superheat, thereby making the intake superheat fall within the range of the second preset superheat to the first preset superheat.

[0061] According to one embodiment of the present invention, 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.

[0062] Furthermore, according to one embodiment of the present invention, controlling the opening of the first throttling element according to the inhalation pressure to keep the inhalation pressure within a preset inhalation pressure range includes: reducing the opening of the first throttling element when the inhalation pressure is greater than a first preset inhalation pressure; increasing the opening of the first throttling element when the inhalation pressure is less than a second preset inhalation pressure; wherein the first preset inhalation pressure is greater than the second preset inhalation pressure.

[0063] Specifically, when the intake superheat is greater than the first preset superheat, the controller can increase the opening of the second throttling element, thus increasing the intake pressure. If the intake pressure is greater than the first preset intake pressure, the controller can decrease the opening of the first throttling element, thus decreasing the intake pressure. If the intake pressure is less than the second preset intake pressure, the controller can increase the opening of the first throttling element, thus increasing the intake pressure. Similarly, when the intake superheat is less than the second preset superheat, the controller can decrease the opening of the second throttling element, thus decreasing the intake pressure. If the intake pressure is less than the second preset intake pressure, the controller can increase the opening of the first throttling element, thus increasing the intake pressure. If the intake pressure is greater than the first preset intake pressure, the controller can decrease the opening of the first throttling element, thus decreasing the intake pressure. When the intake pressure is within the preset intake pressure range, the controller can maintain the opening of the first throttling element unchanged.

[0064] The following is combined with Figure 3 The present invention describes a low-temperature control method for a heat pump system.

[0065] As a concrete example, such as Figure 3 As shown, the low-temperature control method of the heat pump system of the present invention may include the following steps:

[0066] S101, in response to the start command of the heat pump system, controls the compressor to run at the first preset speed.

[0067] S102, control the opening degree of the first throttling element to the first preset opening degree.

[0068] S103, obtain the compressor's suction pressure.

[0069] S104. Determine whether the inhalation pressure has increased to the first preset inhalation pressure. If yes, proceed to step S105; if no, proceed to step S106.

[0070] S105, reduce the opening of the first throttling element to reduce the intake pressure.

[0071] S106, keep the opening of the first throttling element unchanged.

[0072] S107, determine whether the inhalation pressure has decreased to the second preset inhalation pressure. If yes, proceed to step S108; if no, return to step S107.

[0073] S108, keep the opening of the first throttling element unchanged until there is suction superheat at the compressor's suction port.

[0074] S109, the compressor speed is increased according to the preset step size.

[0075] S110, obtains the compressor's suction pressure.

[0076] S111, determine whether the inhalation pressure has reached the second preset inhalation pressure. If yes, proceed to step S112; otherwise, return to step S109.

[0077] S112, keep the compressor speed constant and increase the opening of the first throttling element to increase the suction pressure.

[0078] S113, determine whether the inhalation pressure has reached the first preset inhalation pressure. If yes, proceed to step S114; otherwise, return to step S113.

[0079] S114, keep the opening of the first throttling element unchanged.

[0080] S115, determine whether the compressor speed has been adjusted to the target speed. If yes, proceed to step S116; otherwise, return to step S109.

[0081] S116, Stop adjusting the compressor speed.

[0082] S117, determine whether the intake superheat is greater than the first preset superheat. If yes, proceed to step S118; if no, proceed to step S124.

[0083] S118, increase the opening degree of the second throttling element.

[0084] S119, obtain the compressor's suction pressure.

[0085] S120: Determine whether the inhalation pressure is greater than the first preset inhalation pressure. If yes, proceed to step S121; otherwise, return to step S120.

[0086] S121, reduce the opening degree of the first throttling element.

[0087] S122, determine whether the inhalation pressure is less than the second preset inhalation pressure. If yes, proceed to step S123; otherwise, return to step S122.

[0088] S123, increase the opening degree of the first throttling element.

[0089] S124, determine whether the intake superheat is less than the second preset superheat. If yes, proceed to step S125; otherwise, return to step S124.

[0090] S125, reduce the opening of the second throttling element and return to step S119.

[0091] In summary, the low-temperature control method for a heat pump system according to an embodiment of the present invention first responds to the start-up command of the heat pump system by controlling the compressor to operate and controlling the opening degree of the first throttling element to adjust the compressor's suction pressure until there is suction superheat at the compressor's suction port; then, the compressor speed is gradually adjusted, and the opening degree of the first throttling element is controlled to adjust the compressor's suction pressure, so as to gradually adjust the compressor speed to the target speed within a preset suction pressure range. Therefore, this method can control the first throttling element based on the compressor's suction pressure, effectively avoiding damage to the compressor caused by excessively low suction pressure, and by adjusting the speed based on the compressor's suction pressure feedback, it can avoid damage caused by the compressor drawing a vacuum due to excessively rapid speed increases.

[0092] Corresponding to the above embodiments, the present invention also proposes a heat pump system.

[0093] Figure 4 This is a block diagram of a heat pump system according to an embodiment of the present invention.

[0094] like Figure 4As shown, the heat pump system 200 of this embodiment 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, it implements the above-described low-temperature control method of the heat pump system.

[0095] According to the heat pump system of the present invention, the low temperature control method of the heat pump system described above can control the first throttling element based on the suction pressure of the compressor, which can effectively avoid damage to the compressor caused by excessively low suction pressure. Furthermore, the speed can be adjusted based on the suction pressure feedback of the compressor, which can prevent damage to the compressor caused by excessively rapid increase in speed leading to vacuuming.

[0096] Corresponding to the above embodiments, the present invention also proposes a low-temperature control device for a heat pump system.

[0097] Figure 5 This is a block diagram of a cryogenic control device for a heat pump system according to an embodiment of the present invention.

[0098] like Figure 5 As shown, the low-temperature control device 100 of the heat pump system of the present invention includes a heat pump circuit, the heat pump circuit includes 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.

[0099] The first control module 110 is used to respond to the start command of the heat pump system, control the compressor to work, and control the opening degree of the first throttling element to adjust the compressor's suction pressure until there is suction superheat at the compressor's suction port. The second control module 120 is used to gradually adjust the compressor speed after suction superheat exists at the compressor's suction port, and control the opening degree of the first throttling element to adjust the compressor's suction pressure, so as to gradually adjust the compressor speed to the target speed within the preset suction pressure range.

[0100] According to one embodiment of the present invention, a first control module 110 controls the compressor to operate and controls the opening degree of a first throttling element to adjust the compressor's suction pressure until suction superheat exists at the compressor's suction port. Specifically, it controls the compressor to operate at a first preset speed, controls the opening degree of the first throttling element to a first preset opening degree, and acquires the compressor's suction pressure; when the suction pressure rises to the first preset suction pressure, it reduces 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, it keeps the opening degree of the first throttling element unchanged until suction superheat exists at the compressor's suction port; 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.

[0101] According to one embodiment of the present invention, the first control module 110 is further configured to: acquire the suction temperature of the compressor and determine the saturation temperature corresponding to the suction pressure; acquire the temperature difference between the suction temperature and the saturation temperature corresponding to the suction pressure; and determine that there is suction superheat at the suction port of the compressor when the temperature difference is greater than a preset temperature difference.

[0102] According to one embodiment of the present invention, the second control module 120 gradually adjusts the compressor speed and controls the opening of the first throttling element to adjust the compressor suction pressure, so as to gradually adjust the compressor speed to the target speed within a preset suction pressure range. Specifically, it is used to: increase the compressor speed according to a preset step size and obtain the compressor suction pressure; when the suction pressure reaches a second preset suction pressure, keep the compressor speed unchanged and increase the opening of the first throttling element to increase the suction pressure; and when the suction pressure increases to the first preset suction pressure, keep the opening of the first throttling element unchanged and return to the step of increasing the compressor speed according to a preset step size, until the compressor speed is gradually adjusted to the target speed.

[0103] According to one embodiment of the present invention, 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 the 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 the first end of the second heat exchanger, and a second end of the second heat exchanger is connected to the suction port of the compressor. After the compressor speed is gradually adjusted to the target speed, the second control module 120 is further configured to acquire the suction superheat of the compressor and control the opening degree of the second throttling element based on the suction superheat, so that the suction superheat is within a preset suction superheat range.

[0104] According to one embodiment of the present invention, the second control module 120 controls the opening of the second throttling element based on the intake superheat, so that the intake superheat is within a preset intake superheat range. Specifically, it is used to increase the opening of the second throttling element when the intake superheat is greater than the first preset superheat, and decrease the opening of the second throttling element when the intake superheat is less than the second preset superheat; wherein the first preset superheat is greater than the second preset superheat.

[0105] According to one embodiment of the present invention, after increasing or decreasing the opening of the second throttling element, the second control module 120 is further configured 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.

[0106] According to one embodiment of the present invention, 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, it is used to: reduce the opening of the first throttling element when the intake pressure is greater than the first preset intake pressure; and increase the opening of the first throttling element when the intake pressure is less than the second preset intake pressure; wherein the first preset intake pressure is greater than the second preset intake pressure.

[0107] It should be noted that for details not disclosed in the low-temperature control device of the heat pump system in this embodiment of the invention, please refer to the details disclosed in the low-temperature control method of the heat pump system in this embodiment of the invention, which will not be repeated here.

[0108] According to an embodiment of the present invention, a cryogenic control device for a heat pump system includes a first control module that, in response to a start-up command of the heat pump system, controls the compressor to operate and controls the opening degree of a first throttling element to adjust the compressor's suction pressure until suction superheat exists at the compressor's suction port. After suction superheat exists at the compressor's suction port, a second control module gradually adjusts the compressor's speed and controls the opening degree of the first throttling element to adjust the compressor's suction pressure, thereby gradually adjusting the compressor's speed to the target speed within a preset suction pressure range. Thus, this device can control the first throttling element based on the compressor's suction pressure, effectively preventing damage to the compressor caused by excessively low suction pressure. Furthermore, by adjusting the compressor's speed based on suction pressure feedback, it can prevent damage caused by excessively rapid speed increases leading to compressor vacuum.

[0109] Corresponding to the above embodiments, the present invention also proposes a vehicle.

[0110] like Figure 6 As shown, the vehicle 300 in this embodiment of the invention may include the heat pump system 200 described above, or, as... Figure 7 As shown, the vehicle 300 in this embodiment of the invention may further include the cryogenic control device 100 of the heat pump system described above.

[0111] According to the vehicle of the present invention, the first throttling element can be controlled based on the suction pressure of the compressor by means of the heat pump system or the low temperature control device of the heat pump system, which can effectively avoid damage to the compressor caused by excessively low suction pressure, and the speed can be adjusted based on the suction pressure feedback of the compressor to avoid damage caused by the compressor being vacuumed due to excessively rapid increase in speed.

[0112] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing 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 (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0113] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0114] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions 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 one or more embodiments or examples.

[0115] 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 indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0116] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0117] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for low-temperature control of a heat pump system, characterized in that, The heat pump system includes a heat pump circuit, the heat pump circuit includes a compressor and a first throttling element, the two ends of the first throttling element being respectively connected to the exhaust port and the intake port of the compressor, and the method includes: In response to the start command of the heat pump system, the compressor is controlled to operate, and the opening degree 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, including: The compressor is controlled to operate at a first preset speed, and the opening degree of the first throttling element is controlled to the first preset opening degree, and the suction pressure of the compressor is obtained; When the suction pressure rises to the first preset suction pressure, the opening of the first throttling element is reduced to lower the suction pressure, and when the suction pressure drops to the second preset suction pressure, the opening of the first throttling element is kept unchanged until there is suction superheat 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; Gradually adjusting the compressor speed and controlling the opening degree of the first throttling element to adjust the compressor's suction pressure, so as to gradually adjust the compressor speed to the target speed within a preset suction pressure range, including: The compressor speed is increased by a preset step size, and the compressor suction pressure is obtained; When the suction pressure reaches the second preset suction pressure, the compressor speed is kept constant, and the opening of the first throttling element is increased to raise the suction pressure. When the suction pressure rises to the first preset suction pressure, the opening of the first throttling element is kept constant, and the process returns to the step of increasing the compressor speed according to a preset step size until the compressor speed is gradually adjusted to the target speed.

2. The method according to claim 1, characterized in that, The method further includes: Obtain the suction temperature of the compressor and determine the saturation temperature corresponding to the suction pressure; Obtain the temperature difference between the inhalation temperature and the saturation temperature corresponding to the inhalation pressure; When the temperature difference is greater than a preset temperature difference, it is determined that there is suction superheat at the compressor's intake port.

3. The method according to any one of claims 1-2, characterized in that, 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 the 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 the first end of the second heat exchanger, and a second end of the second heat exchanger is connected to the intake port of the compressor. The method further includes, after gradually adjusting the compressor speed to the target speed: Obtain the suction superheat of the compressor; The opening degree of the second throttling element is controlled according to the intake superheat, so that the intake superheat is within the preset intake superheat range.

4. The method according to claim 3, characterized in that, The step of controlling the opening degree of the second throttling element based on the intake superheat to keep the intake superheat within a preset intake superheat range includes: When the intake superheat is greater than the first preset superheat, the opening of the second throttling element is increased; When the intake superheat is less than the second preset superheat, the opening of the second throttling element is reduced; wherein the first preset superheat is greater than the second preset superheat.

5. The method according to claim 4, characterized in that, After increasing or decreasing the opening of the second throttling element, the method further includes: Obtain the suction pressure of the compressor; The opening degree of the first throttling element is controlled according to the inhalation pressure so that the inhalation pressure is within the preset inhalation pressure range.

6. The method according to claim 5, characterized in that, The step of controlling the opening degree of the first throttling element according to the inhalation pressure to keep the inhalation pressure within the preset inhalation pressure range includes: When the inhalation pressure is greater than the first preset inhalation pressure, the opening of the first throttling element is reduced; When the inhalation pressure is less than the second preset inhalation pressure, the opening of the first throttling element is increased; wherein the first preset inhalation pressure is greater than the second preset inhalation pressure.

7. A low-temperature control device for a heat pump system, characterized in that, The heat pump system includes a heat pump circuit, the heat pump circuit including a compressor and a first throttling element, the two ends of the first throttling element being respectively connected to the exhaust port and the intake port of the compressor, for implementing the method as described in any one of claims 1-6, the device comprising: The first control module is used to respond to the start command of the heat pump system, control the compressor to work, and control the opening degree of the first throttling element to adjust the suction pressure of the compressor until there is suction superheat at the suction port of the compressor. The second control module is used to gradually adjust the speed of the compressor after there is suction superheat at the suction port of the compressor, and to control the opening degree 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.

8. A vehicle, characterized in that, Includes the cryogenic control device for the heat pump system according to claim 7.

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