Control method and device for low-temperature refrigeration of heat pump unit, heat pump unit and computer readable storage medium

Abstract

The invention relates to the technical field of air conditioners, and discloses a control method for low-temperature refrigeration of a heat pump unit, the heat pump unit is provided with a bypass pipeline, the bypass pipeline is connected with an exhaust port of a compressor and an outlet of a condenser, and the bypass pipeline is provided with a bypass electronic expansion valve; the control method comprises the steps that the current outdoor environment temperature and the current high pressure of the heat pump unit are obtained; under the condition that the current outdoor environment temperature and the current high pressure meet preset conditions, the opening degree and the initial opening degree of the bypass electronic expansion valve are determined; the bypass electronic expansion valve is controlled to be opened to the initial opening degree; and according to the real-time high pressure, the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve are adjusted. According to the method, by adjusting the bypass electronic expansion valve and the outdoor fan, the heat pump unit operates stably, and fluctuation of the indoor temperature is reduced. The invention further discloses a control method and device for low-temperature refrigeration of the heat pump unit, the heat pump unit and a computer readable storage medium.

Description

Technical Field

[0001] The present application relates to the technical field of air conditioners, and for example, relates to a control method and device for low-temperature refrigeration of a heat pump unit, a heat pump unit, and a computer-readable storage medium. Background Art

[0002] In existing air-cooled heat pump units, the lowest refrigeration ambient temperature can reach about 5°C. For low-temperature refrigeration control at -5°C, a scheme of using a variable-frequency fan to reduce the wind speed is mostly adopted, but this scheme will have the phenomenon of frequent start-stop of the fan at low ambient temperatures. This phenomenon will cause the unit state to be unstable and the service life of the fan to be shortened.

[0003] Related technologies disclose an air conditioner and its low-temperature refrigeration control method, and a computer-readable storage medium. The air conditioner includes an outdoor heat exchanger, an indoor heat exchanger, and a compressor, and further includes a bypass circuit that can be controlled to be turned on and off. One end of the bypass circuit is connected to the exhaust port of the compressor, and the other end is connected to the outlet end of the outdoor heat exchanger. The low-temperature refrigeration control method includes: obtaining a current pressure characterization parameter, where the pressure characterization parameter includes at least one of outdoor ambient temperature, outdoor heat exchanger coil temperature, exhaust temperature, indoor heat exchanger coil temperature, high-pressure pressure, and low-pressure pressure; judging whether the air conditioner meets a preset low-pressure condition based on the current pressure characterization parameter; when the air conditioner meets the preset low-pressure condition, judging whether the outdoor fan of the air conditioner is at the lowest wind gear; when the outdoor fan of the air conditioner is at the lowest wind gear, controlling the bypass circuit to be turned on.

[0004] In the process of implementing the embodiments of the present disclosure, it is found that there are at least the following problems in the related technologies:

[0005] When the related technology is in a low-pressure state and the outdoor fan is at the lowest wind gear, the bypass circuit is controlled to be turned on. Although the problem of frequent start-up of the outdoor fan is solved, controlling the turn-on of the bypass circuit in the above scenario will seriously affect the refrigeration effect and cause large fluctuations in the indoor temperature.

[0006] It should be noted that the information disclosed in the above background art section is only used to strengthen the understanding of the background of the present application, and therefore may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0007] To have a basic understanding of some aspects of the disclosed embodiments, a simple summary is given below. The summary is not a general review, nor is it intended to identify key / important constituent elements or delineate the protection scope of these embodiments, but rather serves as a preface to the subsequent detailed description.

[0008] Embodiments of the present disclosure provide a control method and device for low-temperature refrigeration of a heat pump unit, a heat pump unit, and a computer-readable storage medium, so as to reduce the impact on the indoor temperature while avoiding frequent startup of the outdoor fan.

[0009] In some embodiments, the heat pump unit is provided with a bypass pipeline, the bypass pipeline is connected to the compressor exhaust port and the condenser outlet, and a bypass electronic expansion valve is provided on the bypass pipeline; the method includes: obtaining the current outdoor ambient temperature and the current high-pressure of the heat pump unit; determining that the bypass electronic expansion valve is opened and the initial opening degree when the current outdoor ambient temperature and the current high-pressure meet the preset conditions; and controlling the bypass electronic expansion valve to open to the initial opening degree; adjusting the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the real-time high-pressure.

[0010] Optionally, the preset conditions include: the current outdoor ambient temperature is less than or equal to the first temperature, the current high-pressure is less than the first pressure, and the continuous duration is greater than the first duration. In this way, using the current outdoor ambient temperature and the current high-pressure as the preset conditions improves the accuracy of judgment.

[0011] Optionally, determining the initial opening degree of the bypass electronic expansion valve includes: determining the initial opening degree of the bypass electronic expansion valve corresponding to the current high-pressure according to the correspondence between the high-pressure range and the initial opening degree; wherein, the larger the initial opening degree, the larger the value of the corresponding high-pressure range. The overall value of the area where the high-pressure is located is larger, and the corresponding initial opening degree is smaller. In this way, it is avoided that the initial opening degree is too large, which causes too large a fluctuation in the indoor temperature while increasing the pressure.

[0012] Optionally, adjusting the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the real-time high-pressure includes: obtaining the change value of the real-time high-pressure when the real-time high-pressure is greater than the first pressure and less than or equal to the second pressure; adjusting the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the change value of the real-time high-pressure; wherein, the change value of the real-time high-pressure is the difference between the real-time high-pressure of the current detection period and the real-time high-pressure of the previous detection period. In this way, within the pressure range, based on the change value of the real-time high-pressure, the outdoor fan and the bypass electronic expansion valve are adjusted. Thereby reducing the heat exchange between the refrigerant in the condenser and the external environment and increasing the pressure of the refrigerant in the evaporator. Or, while increasing the high-pressure, the impact on the indoor temperature is reduced as much as possible.

[0013] Optionally, according to the change value of the real-time high-pressure pressure, adjust the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve, including: when the change value of the real-time high-pressure pressure is less than or equal to the first threshold, reduce the gear of the outdoor fan according to the first gear range, and increase the opening degree of the bypass electronic expansion valve according to the second step range; when the change value of the real-time high-pressure pressure is greater than the first threshold and less than or equal to the second threshold, keep the gear of the outdoor unit fan and the opening degree of the bypass electronic expansion valve unchanged; when the change value of the real-time high-pressure pressure is greater than the second threshold, increase the gear of the outdoor fan according to the first gear range, and reduce the opening degree of the bypass electronic expansion valve according to the third step range. When the change value of the real-time high-pressure pressure is less than or equal to the first threshold, adjusting in the above manner helps to increase the high-pressure pressure so that the high-pressure pressure is within the range of stable operation of the unit. When the change value of the real-time high-pressure pressure is greater than the first threshold and less than or equal to the second threshold, adjusting in the above manner can slow down the change trend of the high-pressure pressure and avoid large fluctuations in the indoor temperature.

[0014] Optionally, according to the real-time high-pressure pressure, adjusting the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve further includes: when the real-time high-pressure pressure is less than or equal to the first pressure, reduce the gear of the outdoor fan according to the first gear range, and increase the opening degree of the bypass electronic expansion valve according to the first step range; when the real-time high-pressure pressure is greater than the second pressure, increase the gear of the outdoor fan according to the second gear range, and reduce the opening degree of the bypass electronic expansion valve according to the fourth step range; wherein, the second gear range is greater than the first gear range, and the fourth step range is greater than the first step range. When the real-time high-pressure pressure is relatively large or small, adjusting the outdoor fan and the bypass electronic expansion valve based on the real-time high-pressure pressure can achieve rapid adjustment of the high-pressure pressure.

[0015] Optionally, after adjusting the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the real-time high-pressure pressure, it further includes: when the outdoor ambient temperature is greater than the first temperature, control the bypass electronic expansion valve to close. In this way, when the outdoor ambient temperature is greater than the first temperature, control the bypass pipeline to be cut off. Thereby, the operating state of the heat pump unit is stabilized, and the probability of frequent startup of the outdoor fan is reduced.

[0016] In some embodiments, the device includes: a processor and a memory storing program instructions, and the processor is configured to execute the control method for low-temperature refrigeration of the heat pump unit as described above when running the program instructions.

[0017] In some embodiments, the heat pump unit includes: a bypass pipeline provided between the compressor exhaust port and the condenser outlet, and a bypass electronic expansion valve is provided on the bypass pipeline; and the control device for low-temperature refrigeration of the heat pump unit as described above, which is used to control the opening degree of the bypass electronic expansion valve and the gear of the outdoor fan.

[0018] In some embodiments, the computer-readable storage medium stores program instructions that, when running, cause a computer to execute the control method for low-temperature refrigeration of a heat pump unit as described above.

[0019] The control method and device for low-temperature refrigeration of a heat pump unit, the heat pump unit, and the computer-readable storage medium provided by the embodiments of the present disclosure can achieve the following technical effects:

[0020] The heat pump unit is provided with a bypass pipeline and a bypass electronic expansion valve. Based on the current outdoor ambient temperature and the current high pressure, it is determined whether to open the bypass electronic expansion valve and the initial opening degree. After controlling the opening of the bypass electronic expansion valve, based on the real-time high pressure, the outdoor fan speed and the opening degree of the bypass electronic expansion valve are adjusted to ensure the reliable operation of the heat pump unit. In this way, by adjusting the bypass electronic expansion valve and the outdoor fan, the heat pump unit operates stably and reduces the temperature fluctuation in the room.

[0021] The above general description and the following description are only exemplary and explanatory, and are not used to limit the present application. Description of the Drawings

[0022] One or more embodiments are exemplarily illustrated by corresponding drawings. These exemplary illustrations and the drawings do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation, and among them:

[0023] Figure 1 is a schematic structural diagram of a heat pump unit provided by an embodiment of the present disclosure;

[0024] Figure 2 is a schematic diagram of a control method for low-temperature refrigeration of a heat pump unit provided by an embodiment of the present disclosure;

[0025] Figure 3 is a schematic diagram of another control method for low-temperature refrigeration of a heat pump unit provided by an embodiment of the present disclosure;

[0026] Figure 4 is a schematic diagram of another control method for low-temperature refrigeration of a heat pump unit provided by an embodiment of the present disclosure;

[0027] Figure 5 is a schematic diagram of another control method for low-temperature refrigeration of a heat pump unit provided by an embodiment of the present disclosure;

[0028] Figure 6 is a schematic diagram of a control device for low-temperature refrigeration of a heat pump unit provided by an embodiment of the present disclosure;

[0029] Figure 7It is a schematic structural diagram of another heat pump unit provided by an embodiment of the present disclosure.

[0030] Reference numerals:

[0031] 200: Heat pump unit; 100: Control device for low-temperature refrigeration of the heat pump unit;

[0032] 11: Bypass pipeline; 12: Bypass electronic expansion valve; 21: Compressor; 22: Four-way valve; 23: Condenser; 24: Outdoor fan; 25: Main electronic expansion valve; 26: Evaporator; 27: Liquid storage tank; 28: Gas-liquid separator; 29: Oil separator; 31: High-pressure pressure sensor;

[0033] 101: Processor; 103: Communication interface; 102: Memory; 104: Bus. Detailed implementation manners

[0034] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The attached drawings are for reference and illustration purposes only and are not used to limit the embodiments of the present disclosure. In the following technical descriptions, for the sake of explanation, multiple details are provided to give a full understanding of the disclosed embodiments. However, one or more embodiments can still be implemented without these details. In other cases, well-known structures and devices can be shown in a simplified manner to simplify the drawings.

[0035] In the embodiments of the present disclosure, terms such as "first" and "second" in the specification, claims and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so as to implement the embodiments of the present disclosure described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0036] Unless otherwise specified, the term "plurality" means two or more.

[0037] In the embodiments of the present disclosure, the character " / " indicates that the objects before and after are in an "or" relationship. For example, A / B means: A or B.

[0038] The term "and / or" is a description of the association relationship of objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, the three relationships of A and B.

[0039] The term "corresponding" can refer to an association relationship or a binding relationship. A corresponding to B means that there is an association relationship or a binding relationship between A and B.

[0040] Combined with Figure 1As shown, the heat pump unit 200 includes a refrigerant circulation circuit and a bypass pipeline 11. The refrigerant circulation circuit includes a compressor 21, a four-way valve 22, a condenser 23, a main electronic expansion valve 25, and an evaporator 26 connected in sequence. The bypass pipeline 11 is connected between the exhaust port of the compressor 21 and the outlet of the condenser 23. More specifically, one end of the bypass pipeline 11 is connected to the pipeline between the four-way valve 22 and the condenser 23, and the other end is connected to the pipeline between the outlet of the condenser 23 and the main electronic expansion valve 25. A bypass electronic expansion valve 12 is provided on the bypass pipeline 11, and the default state of the bypass electronic expansion valve 12 is the closed state, that is, the bypass pipeline 11 is not conducting. The heat pump unit also includes an outdoor fan 24.

[0041] When the heat pump unit is in low-temperature refrigeration, if the operating parameters and the outdoor ambient temperature meet the preset conditions, the bypass electronic expansion valve is opened. In this way, a part of the high-temperature refrigerant does not flow through the condenser, but flows into the evaporator through the bypass pipeline and then flows back to the compressor. Thereby, the pressure on the low-pressure side of the compressor is increased, the balance of the high and low pressures of the entire system is ensured, and the frequent shutdown of the outdoor fan is avoided. In addition, by adjusting the opening degree of the bypass electronic expansion valve, the amount of bypassed refrigerant is adjusted. While adjusting the system pressure, the indoor refrigeration is taken into account to reduce the fluctuation of the indoor temperature.

[0042] Optionally, a high-pressure pressure sensor 31 is provided on the compressor exhaust pipeline for detecting the high-pressure of the unit. Here, by detecting the high-pressure, it is judged whether the bypass pipeline needs to be opened. It can be understood that when refrigerating in a low-temperature environment (low outdoor ambient temperature), the low-pressure is relatively low, and the high-pressure will also be affected. Therefore, by detecting the high-pressure, the change of the low-pressure can be reflected.

[0043] In addition, a liquid storage tank 27, a gas-liquid separator 28, an oil separator 29, and an oil return capillary are also provided in the refrigerant circulation circuit. Thereby, the amount of refrigerant for the operation of the unit is ensured.

[0044] Based on the above heat pump unit, combined with Figure 2 As shown, an embodiment of the present disclosure provides a control method for low-temperature refrigeration of a heat pump unit, including:

[0045] S101, the processor obtains the current outdoor ambient temperature and the current high-pressure of the heat pump unit.

[0046] S102, when the current outdoor ambient temperature and the current high-pressure meet the preset conditions, the processor determines the opening and the initial opening degree of the bypass electronic expansion valve; and controls the bypass electronic expansion valve to open to the initial opening degree.

[0047] S103, the processor adjusts the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the real-time high-pressure.

[0048] Here, the heat pump unit runs in cooling mode. The current outdoor ambient temperature can be obtained through the temperature sensor of the outdoor unit of the heat pump unit, or the temperature of the location of the heat pump unit can be obtained through the network or other means as the current outdoor ambient temperature. The current high-pressure pressure is obtained through the high-pressure pressure sensor described above. If the current outdoor ambient temperature and the current high-pressure pressure meet the preset conditions, it means that the current low-pressure pressure of the heat pump unit is low, and there is a risk of frequent shutdown of the outdoor fan. At this time, it is determined that the bypass electronic expansion valve needs to be opened. At the same time, the initial opening of the bypass electronic expansion valve can also be determined based on the current operating parameters of the heat pump unit, such as the current high-pressure pressure. Then, the bypass electronic expansion valve is controlled to open to the initial opening. Among them, the initial opening needs to be able to improve the low-pressure pressure, and the indoor temperature must also be taken into account.

[0049] After the bypass line is connected, part of the high-temperature and high-pressure refrigerant does not pass through the condenser for heat exchange, but flows into the evaporator after throttling. Therefore, the refrigerant pressure of the evaporator can be improved and the pressure on the low-pressure side of the heat pump unit can be increased. At the same time, the bypass electronic expansion valve reduces the temperature of the refrigerant throttling, and the refrigerant after cooling flows into the evaporator, which weakens the impact on the indoor refrigeration effect. In order to more accurately adjust the pressure of the heat pump unit, the gear position of the outdoor fan and the opening of the bypass electronic expansion valve are adjusted based on the real-time high-pressure pressure. Specifically, the adjustment scheme can be that the greater the real-time high-pressure pressure, the higher the gear position of the outdoor fan (that is, the greater the wind speed), and the smaller the opening of the bypass electronic expansion valve. Alternatively, the outdoor fan and the bypass electronic expansion valve can be adjusted based on the change of the real-time high-pressure pressure to meet the stable operation of the heat pump unit and reduce the fluctuation of the room temperature at the user end.

[0050] The control method for low-temperature refrigeration of a heat pump unit provided by the embodiment of the present disclosure is provided with a bypass pipeline and a bypass electronic expansion valve. Based on the current outdoor ambient temperature and the current high pressure, it is determined whether to open the bypass electronic expansion valve and the initial opening degree of the opening. After the bypass electronic expansion valve is controlled to open, the outdoor fan gear and the opening degree of the bypass electronic expansion valve are adjusted based on the real-time high pressure to ensure the reliable operation of the heat pump unit. In this way, by adjusting the bypass electronic expansion valve and the outdoor fan, the heat pump unit can operate stably and reduce the fluctuation of the indoor temperature.

[0051] Optionally, the preset conditions in step S102 include:

[0052] The current outdoor ambient temperature is less than or equal to the first temperature, the current high pressure is less than the first pressure, and the durations are both greater than the first duration.

[0053] Here, when the current outdoor ambient temperature continuously remains less than or equal to the first temperature, it indicates that the current outdoor ambient temperature is relatively low, and there is a risk of unstable unit status when the heat pump unit operates in low-temperature environment for refrigeration. At this time, if the high-pressure pressure also continuously remains less than the first pressure, it can be determined that the risk of unstable unit status is relatively high. Therefore, the current conditions meet the preset conditions for opening the bypass pipeline. Among them, the first duration can take values from 5 seconds to 15 seconds, and the limitation of the first duration avoids the influence of accidental factors and improves the reliability of judgment.

[0054] Optionally, in step S102, the processor determines the initial opening degree of the bypass electronic expansion valve, including:

[0055] The processor determines the initial opening degree of the bypass electronic expansion valve corresponding to the current high-pressure pressure according to the corresponding relationship between the high-pressure pressure range and the initial opening degree.

[0056] Among them, the larger the initial opening degree, the smaller the value of the corresponding high-pressure pressure range.

[0057] Here, the high-pressure pressure is divided into multiple ranges, and each range corresponds to an initial opening degree. The larger the value of the pressure range, the smaller the corresponding initial opening degree. As an example, the high-pressure pressure range is divided into three ranges, namely [Pd2, Pd1), [Pd3, Pd2), (-∞, Pd3); the corresponding initial opening degrees are K1, K2, K3 respectively. Among them, K3 > K2, K2 > K1; Pd1 > Pd2, Pd2 > Pd3. And Pd1 ≤ P1, where P1 is the first pressure. The overall larger the value of the area where the high-pressure pressure is located, the smaller the corresponding initial opening degree. In this way, it is avoided that the initial opening degree is too large, which may cause excessive indoor temperature fluctuations while increasing the pressure.

[0058] Combined Figure 3 As shown, another control method for low-temperature refrigeration of a heat pump unit provided by an embodiment of the present disclosure includes:

[0059] S101, the processor obtains the current outdoor ambient temperature and the current high-pressure pressure of the heat pump unit.

[0060] S102, when the current outdoor ambient temperature and the current high-pressure pressure meet the preset conditions, the processor determines the opening and the initial opening degree of the bypass electronic expansion valve; and controls the bypass electronic expansion valve to open to the initial opening degree.

[0061] S131, when the real-time high-pressure pressure is greater than the first pressure and less than or equal to the second pressure, the processor obtains the change value of the real-time high-pressure pressure.

[0062] S132, the processor adjusts the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the change value of the real-time high-pressure pressure.

[0063] Among them, the change value of the real-time high-pressure pressure is the difference between the real-time high-pressure pressure in the current detection period and the real-time high-pressure pressure in the previous detection period.

[0064] Here, after the bypass electronic expansion valve is opened to a preset opening degree, the real-time high-pressure pressure gradually increases. Further combined with the real-time high-pressure pressure, the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve are adjusted. Specifically, when the real-time high-pressure pressure is greater than the first pressure and less than or equal to the second pressure, although the high-pressure pressure of the unit rises, there is still a risk of unstable state in this pressure range. Therefore, in this pressure range, based on the change value of the real-time high-pressure pressure, the outdoor fan and the bypass electronic expansion valve are adjusted. Among them, the change value of the real-time high-pressure pressure is the difference between the real-time high-pressure pressure in the current detection period and the real-time high-pressure pressure in the previous detection period.

[0065] If the change value of the real-time high-pressure pressure is negative, it indicates that the change trend of the real-time high-pressure pressure is a decreasing trend. At this time, it is necessary to increase the opening degree of the bypass electronic expansion valve to increase the high-temperature and high-pressure refrigerant flowing into the evaporator. At the same time, the gear of the outdoor fan can be further reduced, that is, the rotation speed of the outdoor fan is smaller. Thereby reducing the heat exchange between the refrigerant in the condenser and the external environment and increasing the pressure of the refrigerant in the evaporator. Similarly, if the change value of the real-time high-pressure pressure is positive, it indicates that the change trend of the real-time high-pressure pressure is an increasing trend. At this time, the rotation speed of the outdoor fan can be appropriately increased or maintained, and at the same time, the opening degree of the bypass electronic expansion valve is reduced. Thereby while increasing the high-pressure pressure, minimizing the impact on the indoor temperature.

[0066] Optionally, in step S132, the processor adjusts the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the change value of the real-time high-pressure pressure, including:

[0067] When the change value of the real-time high-pressure pressure is less than or equal to the first threshold, the processor reduces the gear of the outdoor fan according to the first gear amplitude and increases the opening degree of the bypass electronic expansion valve according to the second step amplitude.

[0068] When the change value of the real-time high-pressure pressure is greater than the first threshold and less than or equal to the second threshold, the processor maintains the gear of the outdoor unit fan and the opening degree of the bypass electronic expansion valve.

[0069] When the change value of the real-time high-pressure pressure is greater than the second threshold, the processor increases the gear of the outdoor fan according to the first gear amplitude and reduces the opening degree of the bypass electronic expansion valve according to the third step amplitude.

[0070] Here, a first threshold and a second threshold are set to define the change trend and the magnitude of the change value of the real-time high-pressure pressure. Specifically, if the change value of the real-time high-pressure pressure is less than or equal to the first threshold, it indicates that the real-time high-pressure pressure changes slowly and the change amount is small. At this time, the outdoor fan speed is reduced by the first step, and at the same time, the opening degree of the bypass electronic expansion valve is increased by the second step. In this way, it helps to increase the high-pressure pressure and keep the high-pressure pressure within the stable operation range of the unit.

[0071] If the change value of the real-time high-pressure pressure is greater than the first threshold and less than or equal to the second threshold, it indicates that the change trend of the high-pressure pressure is relatively gentle and the change amount is appropriate. At this time, the outdoor fan speed and the opening degree of the bypass electronic expansion valve can be maintained. In this way, it ensures a steady increase in the high-pressure pressure and avoids overshoot. If the change value of the real-time high-pressure pressure is greater than the first threshold, it indicates that the high-pressure pressure increases significantly and the change amount is large. At this time, the outdoor fan speed is increased by the first step, and at the same time, the opening degree of the bypass electronic expansion valve is reduced by the third step. In this way, the change trend of the high-pressure pressure is slowed down and large fluctuations in the indoor temperature are avoided.

[0072] Optionally, after reducing the outdoor fan speed, the latest outdoor fan speed is greater than the minimum speed. Among them, the minimum speed is 0 (0 is the shutdown speed). Here, when reducing the outdoor fan speed, it is necessary to ensure that the adjusted outdoor fan is still in the operating state. That is, the outdoor fan speed is greater than 0. If the adjusted outdoor fan speed is 0, the speed is not adjusted and the current speed of the fan is maintained; or, the speed of the outdoor fan is adjusted so that the fan runs at the minimum speed. In this way, it ensures that the outdoor fan is always in the operating state.

[0073] Optionally, the first step is the minimum adjustment step amplitude of the outdoor fan, and the third step is greater than or equal to the second step. Here, the minimum adjustment step amplitude of the outdoor fan is generally one-step adjustment, so the first step is one step. As an example, the outdoor fan speeds from high to low are 5, 4, 3, 2, 1, and 0. The current outdoor fan speed is 2, and after adjusting the first step, the outdoor fan speed is 1. The third step can be greater than the second step, or the two are equal. In this way, the increasing step amplitude of the bypass electronic expansion valve is inhibited, and the decreasing step amplitude of the bypass electronic expansion valve is promoted to avoid a large impact on indoor refrigeration.

[0074] Combined with Figure 4 As shown, another control method for low-temperature refrigeration of a heat pump unit provided by an embodiment of the present disclosure includes:

[0075] S101, the processor obtains the current outdoor ambient temperature and the current high-pressure pressure of the heat pump unit.

[0076] S102. When the current outdoor ambient temperature and the current high-pressure satisfy the preset conditions, the processor determines to open the bypass electronic expansion valve and its initial opening degree, and controls the bypass electronic expansion valve to open to the initial opening degree.

[0077] S131. When the real-time high-pressure is greater than the first pressure and less than or equal to the second pressure, the processor obtains the change value of the real-time high-pressure.

[0078] S132. The processor adjusts the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the change value of the real-time high-pressure.

[0079] Wherein, the change value of the real-time high-pressure is the difference between the real-time high-pressure of the current detection period and the real-time high-pressure of the previous detection period.

[0080] S133. When the real-time high-pressure is less than or equal to the first pressure, the processor reduces the gear of the outdoor fan by the first gear range and increases the opening degree of the bypass electronic expansion valve by the first step range.

[0081] S134. When the real-time high-pressure is greater than the second pressure, the processor increases the gear of the outdoor fan by the second gear range and reduces the opening degree of the bypass electronic expansion valve by the fourth step range.

[0082] Wherein, the second gear range is greater than the first gear range, and the fourth step range is greater than the first step range.

[0083] Here, when the real-time high-pressure is less than or equal to the first pressure, it indicates that the real-time high-pressure is still on the low side. At this time, there is no need to obtain the change value of the real-time high-pressure, and the gear of the outdoor fan can be directly reduced and the bypass electronic expansion valve can be enlarged. Thus, the high-pressure can be quickly improved and the outdoor fan can be prevented from stopping. Similarly, when the real-time high-pressure is greater than the second pressure, it indicates that the real-time high-pressure is on the high side. At this time, the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve can also be directly adjusted. Thus, the long-term influence on indoor refrigeration can be avoided, and it is difficult for the refrigerating capacity to meet the refrigeration demand. Wherein, the second gear range is greater than the first gear range, and the fourth step range is greater than the first step range. As an example, the second gear range is 2 gears or 3 gears. More preferably, the first step range is greater than the second step range. In this way, the rapid adjustment of the high-pressure is realized, and when the high-pressure is between the first pressure and the second pressure, the slow adjustment is carried out based on the change value.

[0084] Combined with Figure 5 As shown, another control method for low-temperature refrigeration of a heat pump unit provided by an embodiment of the present disclosure includes:

[0085] S101. The processor obtains the current outdoor ambient temperature and the current high-pressure of the heat pump unit.

[0086] S102. When the current outdoor ambient temperature and the current high-pressure satisfy the preset conditions, the processor determines to open the bypass electronic expansion valve and the initial opening degree, and controls the bypass electronic expansion valve to open to the initial opening degree.

[0087] S103. The processor adjusts the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the real-time high-pressure.

[0088] S204. When the outdoor ambient temperature is greater than the first temperature, the processor controls the bypass electronic expansion valve to close.

[0089] Here, during the process of adjusting the high-pressure, even if the high-pressure reaches the stable operation range of the heat pump unit, the bypass electronic expansion valve remains in the open state. This is because when the outdoor ambient temperature is relatively low, if the bypass pipeline is not conducting, there will still be an unstable operation state during the operation of the unit. Therefore, adjusting the opening degree of the bypass electronic expansion valve can maintain the stable operation of the unit at low temperatures. When the outdoor ambient temperature is greater than the first temperature, the bypass pipeline is controlled to be cut off. At this time, the operation state of the heat pump unit is stable, and the probability of frequent startup of the outdoor fan is small. In addition, in order to improve the accuracy of detection, the bypass electronic expansion valve can be closed when the outdoor ambient temperature is greater than the first temperature and after maintaining the second duration. The value range of the second duration is 5 seconds to 15 seconds.

[0090] Combined Figure 6 As shown, the embodiment of the present disclosure provides a control device 100 for low-temperature refrigeration of a heat pump unit, including a processor 101 and a memory 102. Optionally, the device may further include a communication interface 103 and a bus 104. Among them, the processor 101, the communication interface 103, and the memory 102 can complete mutual communication through the bus 104. The communication interface 103 can be used for information transmission. The processor 101 can call the logical instructions in the memory 102 to execute the control method for low-temperature refrigeration of the heat pump unit in the above embodiment.

[0091] In addition, when the logical instructions in the above-mentioned memory 102 are implemented in the form of a software functional unit and sold or used as an independent product, they can be stored in a computer-readable storage medium.

[0092] The memory 102, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as the program instructions / modules corresponding to the method in the embodiment of the present disclosure. The processor 101 executes functional applications and data processing by running the program instructions / modules stored in the memory 102, that is, implements the control method for low-temperature refrigeration of the heat pump unit in the above embodiment.

[0093] The memory 102 may include a program storage area and a data storage area. Among them, the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created according to the use of the terminal device, etc. In addition, the memory 102 may include a high-speed random access memory and may also include a non-volatile memory.

[0094] Combined Figure 7 As shown, an embodiment of the present disclosure provides a heat pump unit 200, including: a refrigerant circulation circuit, a bypass pipeline, and the above-mentioned control device 100 for low-temperature refrigeration of the heat pump unit. The bypass pipeline is arranged between the compressor exhaust port and the condenser outlet, and a bypass electronic expansion valve is provided on the bypass pipeline. The control device 100 for low-temperature refrigeration of the heat pump unit is electrically connected to the bypass electronic expansion valve and the outdoor fan, and is used to control the opening degree of the bypass electronic expansion valve and the gear of the outdoor fan. The installation relationship described here is not limited to being placed inside the heat pump unit, but also includes installation connections with other components, including but not limited to physical connections, electrical connections, or signal transmission connections, etc. Those skilled in the art can understand that the control device 100 for low-temperature refrigeration of the heat pump unit can be adapted to a feasible air-conditioning main body, thereby realizing other feasible embodiments.

[0095] An embodiment of the present disclosure provides a computer-readable storage medium storing computer-executable instructions, and the computer-executable instructions are set to execute the above-mentioned control method for low-temperature refrigeration of the heat pump unit.

[0096] The technical solution of the embodiment of the present disclosure can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes one or more instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the embodiment of the present disclosure. The foregoing storage medium may be a non-transitory storage medium, such as: a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk, or an optical disc, etc., which are various media that can store program codes.

[0097] The above description and the accompanying drawings fully illustrate the embodiments of the present disclosure, enabling those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, process, and other changes. Embodiments only represent possible variations. Unless explicitly required, individual components and functions are optional, and the order of operations may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terms used in this application are only for describing embodiments and do not limit the claims. As used in the description of the embodiments and the claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to also include the plural forms. Similarly, as used in this application, the term "and / or" refers to any and all possible combinations including one or more of the associated listed items. Additionally, when used in this application, the term "comprise" and its variants "comprises" and / or "comprising" etc. mean the presence of the stated features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groupings of these. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, or apparatus comprising the element. Herein, what each embodiment focuses on may be the differences from other embodiments, and the same or similar parts among the embodiments may be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method parts disclosed in the embodiments, the relevant parts may refer to the description of the method parts.

[0098] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner can depend on the specific application and design constraints of the technical solution. The skilled person can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the embodiments of the present disclosure. The skilled person can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated herein.

[0099] In the embodiments disclosed in this document, the disclosed methods, products (including but not limited to devices, equipment, etc.) can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units can be merely a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Additionally, the displayed or discussed couplings or direct couplings or communication connections between each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms. The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to implement this embodiment. Additionally, in the embodiments of the present disclosure, the various functional units can be integrated in one processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit.

[0100] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code that contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions marked in the blocks can occur in a different order than marked in the accompanying drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks can also occur in a different order than disclosed in the description. Sometimes, there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. Each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

Claims

1. A control method for low-temperature refrigeration of a heat pump unit, characterized in that, The heat pump unit is provided with a bypass pipeline, the bypass pipeline connects the compressor exhaust port and the condenser outlet, and a bypass electronic expansion valve is arranged on the bypass pipeline; the control method includes: Obtain the current outdoor ambient temperature and the current high-pressure of the heat pump unit; When the current outdoor ambient temperature and the current high-pressure meet the preset conditions, determine that the bypass electronic expansion valve is opened and the initial opening degree; and, control the bypass electronic expansion valve to open to the initial opening degree; Adjust the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the real-time high-pressure.

2. The method according to claim 1, characterized in that, The preset conditions include: The current outdoor ambient temperature is less than or equal to the first temperature, the current high-pressure is less than the first pressure, and the continuous duration is greater than the first duration.

3. The method according to claim 1, characterized in that Determining the initial opening degree of the bypass electronic expansion valve includes: According to the corresponding relationship between the high-pressure range and the initial opening degree, determine the initial opening degree of the bypass electronic expansion valve corresponding to the current high-pressure; Wherein, the larger the initial opening degree, the larger the value of the corresponding high-pressure range.

4. The method according to any one of claims 1 to 3, characterized in that Adjusting the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the real-time high-pressure includes: When the real-time high-pressure is greater than the first pressure and less than or equal to the second pressure, obtain the change value of the real-time high-pressure; Adjust the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the change value of the real-time high-pressure; Wherein, the change value of the real-time high-pressure is the difference between the real-time high-pressure of the current detection period and the real-time high-pressure of the previous detection period.

5. The method according to claim 4, characterized in that Adjusting the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the change value of the real-time high-pressure includes: When the change value of the real-time high-pressure is less than or equal to the first threshold, reduce the gear of the outdoor fan by the first gear amplitude and increase the opening degree of the bypass electronic expansion valve by the second step amplitude; When the change value of the real-time high-pressure is greater than the first threshold and less than or equal to the second threshold, keep the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve; When the change value of the real-time high-pressure is greater than the second threshold, increase the gear of the outdoor fan by the first gear amplitude and reduce the opening degree of the bypass electronic expansion valve by the third step amplitude.

6. The method according to claim 4, characterized in that Adjusting the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the real-time high-pressure further includes: When the real-time high-pressure is less than or equal to the first pressure, reduce the gear of the outdoor fan by the first gear amplitude and increase the opening degree of the bypass electronic expansion valve by the first step amplitude; When the real-time high-pressure is greater than the second pressure, increase the gear of the outdoor fan by the second gear amplitude and reduce the opening degree of the bypass electronic expansion valve by the fourth step amplitude; Wherein, the second gear amplitude is greater than the first gear amplitude, and the fourth step amplitude is greater than the first step amplitude.

7. The method according to any one of claims 1 to 6, characterized in that, After adjusting the gear of the outdoor fan and the opening degree of the bypass electronic expansion valve according to the real-time high-pressure, it further includes: When the outdoor ambient temperature is greater than the first temperature, control the bypass electronic expansion valve to close.

8. A control device for low-temperature refrigeration of a heat pump unit, comprising a processor and a memory storing program instructions, characterized in that, The processor is configured to execute the control method for low-temperature refrigeration of a heat pump unit according to any one of claims 1 to 7 when running the program instructions.

9. A heat pump unit, characterized in that, Including: A bypass pipeline is arranged between the compressor exhaust port and the condenser outlet, and a bypass electronic expansion valve is provided on the bypass pipeline; The control device for low-temperature refrigeration of a heat pump unit according to claim 8, which is used to control the opening degree of the bypass electronic expansion valve and the gear of the outdoor fan.

10. A computer-readable storage medium storing program instructions, characterized in that, When the program instructions are running, they are used to cause a computer to execute the control method for low-temperature refrigeration of a heat pump unit according to any one of claims 1 to 7.

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