Low-temperature heat pump air conditioner control system and method

Abstract

The invention discloses a low-temperature heat pump air conditioner control system and method. A compressor, a first heat exchanger, a first expansion valve, a second heat exchanger and a gas-liquid separator of the low-temperature heat pump air conditioner control system are sequentially connected, and the compressor is further connected with the gas-liquid separator in an end-to-end mode. The second expansion valve is connected between the input end of the gas-liquid separator and the input end of the first heat exchanger; the first temperature pressure sensor is used for acquiring first pressure information of a pipeline between the second expansion valve and the gas-liquid separator; the environment temperature sensor is used for acquiring environment temperature information; the controller is in communication connection with the first expansion valve, the second expansion valve, the first temperature pressure sensor and the environment temperature sensor and used for controlling the opening degree of the first expansion valve and the opening degree of the second expansion valve according to the obtained first pressure information, environment temperature information and preset target pressure. The low-temperature heat pump air conditioner control system is high in heating speed, low in energy consumption and high in control precision.

Description

Technical Field

[0001] The present invention relates to the technical field of xx, and particularly to a low-temperature heat pump air-conditioning control system and method. Background Art

[0002] At present, the existing heating systems on the market cannot quickly complete the heating of the air-conditioning box at extremely low temperatures, with a slow heating rate, a long time taken to reach the ideal outlet air temperature. If the heating rate of the air-conditioning needs to be increased, electrical components such as high-power heaters need to be added, resulting in higher energy consumption and lower control accuracy. Summary of the Invention

[0003] The present invention provides a low-temperature heat pump air-conditioning control system and method to solve the problems of slow heating speed, high energy consumption, and low control accuracy of the existing heating systems.

[0004] In a first aspect, an embodiment of the present invention provides a low-temperature heat pump air-conditioning control system, including a compressor, a first heat exchanger, a first expansion valve, a second heat exchanger, a gas-liquid separator, a second expansion valve, a first temperature and pressure sensor, an ambient temperature sensor, and a controller;

[0005] The output end of the compressor, the input end of the first heat exchanger, the output end of the first heat exchanger, the input end of the first expansion valve, the output end of the first expansion valve, the first input end of the second heat exchanger, the first output end of the second heat exchanger, the input end of the gas-liquid separator, the output end of the gas-liquid separator, and the input end of the compressor are connected in sequence;

[0006] The second expansion valve is connected between the input end of the gas-liquid separator and the input end of the first heat exchanger;

[0007] The first temperature and pressure sensor is used to obtain the first pressure information of the pipeline between the second expansion valve and the gas-liquid separator;

[0008] The ambient temperature sensor is used to obtain the ambient temperature information;

[0009] The controller is respectively communicatively connected with the first expansion valve, the second expansion valve, the first temperature and pressure sensor, and the ambient temperature sensor, and is used to obtain the first pressure information and the ambient temperature information, and control the opening degrees of the first expansion valve and the second expansion valve according to the first pressure information, the ambient temperature information, and a preset target pressure.

[0010] Optionally, the low-temperature heat pump air-conditioning control system further includes a first switch, a first temperature sensor, and a motor;

[0011] The output terminal of the first switch, the second input terminal of the second heat exchanger, the second output terminal of the second heat exchanger, and the input terminal of the first switch are connected in sequence;

[0012] The motor is located between the second output terminal of the second heat exchanger and the input terminal of the first switch;

[0013] The first temperature sensor is used to obtain the second temperature information on the second output terminal side of the second heat exchanger;

[0014] The first temperature and pressure sensor is also used to obtain the first temperature information of the pipeline between the second expansion valve and the gas-liquid separator;

[0015] The controller is also communicatively connected to the first temperature sensor and the motor respectively, and is used to obtain the second temperature information, and control the locked-rotor power of the motor according to the first temperature information and the second temperature information.

[0016] Optionally, the low-temperature heat pump air-conditioning system further includes a heater;

[0017] The heater is located between the motor and the input terminal of the first switch;

[0018] The controller is also communicatively connected to the heater, and is used to control the power of the heater according to the first temperature information, the second temperature information, and the locked-rotor power.

[0019] Optionally, the low-temperature heat pump air-conditioning system further includes a heater and a second temperature sensor;

[0020] The heater is located between the motor and the input terminal of the first switch;

[0021] The second temperature sensor is used to obtain the third temperature information of the pipeline between the heater and the input terminal of the first switch;

[0022] The controller is also communicatively connected to the second temperature sensor and the heater respectively, and is used to obtain the third temperature information, and control the start-stop state of the motor locked-rotor and / or the start-stop state of the heater according to the third temperature information.

[0023] Optionally, the low-temperature heat pump air-conditioning system further includes a battery, a second switch, a third temperature sensor, and a fourth temperature sensor; the battery includes a first end and a second end;

[0024] The input terminal of the second switch is connected to the second output terminal of the second heat exchanger, the first output terminal of the second switch is connected to the first end, and the second output terminal of the second switch is respectively connected to the input terminal of the first switch and the second end;

[0025] The third temperature sensor is configured to obtain fourth temperature information of the first end side of the battery;

[0026] The fourth temperature sensor is configured to obtain fifth temperature information of the second end side of the battery;

[0027] The controller is further communicatively connected to the second switch, the third temperature sensor, and the fourth temperature sensor respectively, and is configured to obtain the fourth temperature information and the fifth temperature information, and control the state of the second switch according to the third temperature information, the fourth temperature information, and the fifth temperature information.

[0028] Optionally, the low-temperature heat pump air-conditioning system further includes an air outlet temperature sensor, an indoor temperature sensor, and a light intensity sensor;

[0029] The air outlet temperature sensor is configured to obtain air outlet temperature information; the indoor temperature sensor is configured to obtain indoor temperature information; the light intensity sensor is configured to obtain light intensity information;

[0030] The controller is communicatively connected to the air outlet temperature sensor, the indoor temperature sensor, and the light intensity sensor respectively, and is configured to obtain the air outlet temperature information, the indoor temperature information, and the light intensity information, and control the rotation speed and start / stop state of the compressor according to the air outlet temperature information, the indoor temperature information, the light intensity information, and the ambient temperature information.

[0031] Optionally, the low-temperature heat pump air-conditioning system further includes a second temperature and pressure sensor and a first pressure sensor;

[0032] The second temperature and pressure sensor is configured to obtain the suction pressure information of the compressor;

[0033] The first pressure sensor is configured to obtain the discharge pressure information of the compressor;

[0034] The controller is communicatively connected to the second temperature and pressure sensor and the first pressure sensor respectively, and is configured to obtain the suction pressure information and the discharge pressure information, and adjust the rotation speed and start / stop state of the compressor according to the suction pressure information and the discharge pressure information.

[0035] In a second aspect, an embodiment of the present invention provides a low-temperature heat pump air-conditioning control method, which is applied to the low-temperature heat pump air-conditioning control system described in the first aspect. The low-temperature heat pump air-conditioning control method includes:

[0036] Obtain the first pressure information and the ambient temperature information;

[0037] Control the opening degrees of the first expansion valve and the second expansion valve according to the first pressure information, the ambient temperature information, and a preset target pressure.

[0038] Optionally, controlling the opening degree of the first expansion valve according to the first pressure information, the ambient temperature information, and a preset target pressure includes:

[0039] Determine a first proportional gain and a first integral gain according to the difference between the preset target pressure and the first pressure information;

[0040] Determine the initial opening degree of the first expansion valve according to the ambient temperature information;

[0041] Determine the opening degree of the first expansion valve according to the following corresponding relationship:

[0042]

[0043] where S1 represents the opening degree of the first expansion valve, K p1 represents the first proportional gain, P0 represents the preset target pressure, P (n) represents the first pressure information collected by the first temperature and pressure sensor for the nth time, K i1 represents the first integral gain, S 10 represents the initial opening degree of the first expansion valve;

[0044] Controlling the opening degree of the second expansion valve according to the first pressure information, the ambient temperature information, and a preset target pressure includes:

[0045] Determine a second proportional gain and a second integral gain according to the difference between the preset target pressure and the first pressure information;

[0046] Determine the initial opening degree of the second expansion valve according to the ambient temperature information;

[0047] Determine the opening degree of the second expansion valve according to the following corresponding relationship:

[0048]

[0049] where S2 represents the opening degree of the second expansion valve, K p2 represents the second proportional gain, P0 represents the preset target pressure, P (n) represents the first pressure information collected by the first temperature and pressure sensor for the nth time, K i2 represents the second integral gain, S 20 represents the initial opening degree of the second expansion valve.

[0050] Optionally, the low-temperature heat pump air-conditioning control method further includes:

[0051] Obtain the air outlet temperature information, indoor temperature information, and light intensity information;

[0052] Control the rotational speed and start / stop state of the compressor according to the air outlet temperature information, indoor temperature information, light intensity information, and ambient temperature information.

[0053] The technical solution of the embodiment of the present invention is to set a second expansion valve between the input end of the gas-liquid separator and the input end of the first heat exchanger, and control the opening degree of the second expansion valve according to the obtained first pressure information of the pipeline between the second expansion valve and the gas-liquid separator, ambient temperature information, and preset target pressure, that is, control a part of the high-temperature and high-pressure refrigerant gas (hot gas) discharged by the compressor to bypass to the input end side of the compressor, avoiding faults caused by pressure imbalance in the low-temperature heat pump air conditioner at low temperatures, which is beneficial to improving the heating continuity, increasing the heating speed, without the need to add a high-power heater to achieve low-temperature heating, with low energy consumption. At the same time, control the opening degrees of the first expansion valve and the second expansion valve according to the obtained first pressure information of the pipeline between the second expansion valve and the gas-liquid separator, ambient temperature information, and preset target pressure, that is, control the opening degrees of the first expansion valve and the second expansion valve through the coordinated control of the ambient temperature and system parameters, which can significantly improve the energy efficiency and reliability of the low-temperature heat pump air conditioner and is beneficial to improving the control accuracy.

[0054] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0056] Figure 1 It is a schematic structural diagram of a low-temperature heat pump air conditioner control system provided by an embodiment of the present invention;

[0057] Figure 2 It is a schematic structural diagram of another low-temperature heat pump air conditioner control system provided by an embodiment of the present invention;

[0058] Figure 3 It is a schematic structural diagram of yet another low-temperature heat pump air conditioner control system provided by an embodiment of the present invention;

[0059] Figure 4Schematic structural diagram of another low-temperature heat pump air-conditioning control system provided by an embodiment of the present invention;

[0060] Figure 5 Flowchart of a low-temperature heat pump air-conditioning control method provided by an embodiment of the present invention;

[0061] Figure 6 Flowchart of another low-temperature heat pump air-conditioning control method provided by an embodiment of the present invention. Detailed implementation manners

[0062] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0063] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices. The terms "upper", "lower", "left", "right", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to illustrate the relative positional relationship between the components or constituent parts, and do not particularly limit the specific installation orientation of each component or constituent part.

[0064] Figure 1 Schematic structural diagram of a low-temperature heat pump air-conditioning control system provided by an embodiment of the present invention. Refer to Figure 1 , the low-temperature heat pump air-conditioning control system in the embodiments of the present invention includes a compressor 10, a first heat exchanger 20, a first expansion valve 30, a second heat exchanger 40, a gas-liquid separator 50, a second expansion valve 60, a first temperature and pressure sensor 70, an ambient temperature sensor 80, and a controller 90.

[0065] The output end of the compressor 10, the input end of the first heat exchanger 20, the output end of the first heat exchanger 20, the input end of the first expansion valve 30, the output end of the first expansion valve 30, the first input end of the second heat exchanger 40, the first output end of the second heat exchanger 40, the input end of the gas-liquid separator 50, the output end of the gas-liquid separator 50, and the input end of the compressor 10 are connected in sequence. The second expansion valve 60 is connected between the input end of the gas-liquid separator 50 and the input end of the first heat exchanger 20.

[0066] The first temperature and pressure sensor 70 is used to obtain the first pressure information of the pipeline between the second expansion valve 60 and the gas-liquid separator 50. The ambient temperature sensor 80 is used to obtain the ambient temperature information. The controller 90 is communicatively connected to the first expansion valve 30, the second expansion valve 60, the first temperature and pressure sensor 70, and the ambient temperature sensor 80 respectively, and is used to obtain the first pressure information and the ambient temperature information, and control the opening degrees of the first expansion valve 30 and the second expansion valve 60 according to the first pressure information, the ambient temperature information, and the preset target pressure.

[0067] Exemplarily, the low-temperature and low-pressure gaseous refrigerant will be converted into a high-temperature and high-pressure gaseous refrigerant after being compressed by the compressor 10. Then, the high-temperature and high-pressure gaseous refrigerant will enter the first heat exchanger 20 (i.e., the indoor-side heat exchanger, and at this time the first heat exchanger 20 is a condenser) for heat exchange. During this process, heat will be released to the indoor air to increase the indoor temperature, and the high-temperature and high-pressure gaseous refrigerant will be converted into a high-pressure and medium-temperature liquid refrigerant due to heat release. Then, the high-pressure and medium-temperature liquid refrigerant will enter the first expansion valve 30 for throttling. After being throttled by the first expansion valve 30, the high-pressure and medium-temperature liquid refrigerant will be converted into a low-temperature and low-pressure gas-liquid mixed state refrigerant. After that, the low-temperature and low-pressure gas-liquid mixed state refrigerant will enter the second heat exchanger 40 for heat exchange. During this process, the low-temperature and low-pressure gas-liquid mixed state refrigerant will absorb the heat of the coolant in the second heat exchanger 40 and be converted into a low-temperature and low-pressure gaseous refrigerant. Finally, the low-temperature and low-pressure gaseous refrigerant will pass through the gas-liquid separator 50 and enter the compressor 10. It should be noted that the gas-liquid separator 50 is provided to prevent the liquid refrigerant remaining in the low-temperature and low-pressure gaseous refrigerant from entering the compressor 10, causing liquid hammer and thus damaging the compressor 10. When the low-temperature heat pump air conditioner is operating in the heating state, the refrigerant will continuously undergo the above process to achieve the purpose of increasing the indoor temperature.

[0068] The second expansion valve 60 is connected between the input end of the gas-liquid separator 50 and the input end of the first heat exchanger 20. Part of the high-temperature and high-pressure gaseous refrigerant output from the second expansion valve will enter the input end of the gas-liquid separator 50 and be mixed with the low-temperature and low-pressure gaseous refrigerant output from the first output end of the second heat exchanger 40 to increase the pressure of the gaseous refrigerant entering the input end of the compressor 10, prevent the compressor 10 from stopping due to low-pressure alarm, and thus interrupt the heating of the low-temperature heat pump air conditioner, affecting the heating speed.

[0069] The controller 90 is communicatively connected to the first temperature and pressure sensor 70, and can obtain the first pressure information of the pipeline between the second expansion valve 60 and the gas-liquid separator 50 through the first temperature and pressure sensor 70. The controller 90 is also communicatively connected to the ambient temperature sensor 80, and can obtain the ambient temperature information through the ambient temperature sensor 80. The low-temperature heat pump air conditioner control system in the embodiment of the present invention further includes a memory (such as an electrically erasable programmable read-only memory EEROM). The preset target pressure in the embodiment of the present invention can be preset and stored in the memory by those skilled in the art according to actual needs. The controller 90 is also communicatively connected to the memory. When the low-temperature heat pump air conditioner performs heating work, that is, when the low-temperature heat pump air conditioner control system works, the controller 90 will obtain the preset target pressure through the memory. It can be understood that when the ambient temperature is different and the opening degrees of the first expansion valve 30 and the second expansion valve 60 are the same, the time taken to raise the indoor temperature to the same temperature will be different. The lower the ambient temperature, the slower the heating speed. To ensure that the heating rate of the low-temperature heat pump air conditioner remains consistent at different ambient temperatures and prevent the compressor 10 from stopping due to low-pressure alarm, thereby improving the control accuracy of the low-temperature heat pump air conditioner control system, that is, improving the precise control of the indoor temperature, the opening degrees of the first expansion valve 30 and the second expansion valve 60 can be controlled according to the first pressure information, the ambient temperature information, and the preset target pressure, that is, the opening degrees of the first expansion valve 30 and the second expansion valve 60 are controlled by the coordination of the ambient temperature and the system parameters.

[0070] In the embodiment of the present invention, a second expansion valve 60 is provided between the input end of the first heat exchanger 20 and the input end of the gas-liquid separator 50, and the opening degree of the second expansion valve 60 is controlled according to the acquired first pressure information of the pipeline between the second expansion valve 60 and the gas-liquid separator 50, the ambient temperature information, and the preset target pressure, that is, a part of the high-temperature and high-pressure refrigerant gas (hot gas) discharged by the compressor 10 is bypassed to the input end side of the compressor 10, avoiding failures caused by pressure imbalance of the low-temperature heat pump air conditioner at low temperatures, being beneficial to improving the heating continuity, increasing the heating speed, not requiring a large-power heater to be added for realizing low-temperature heating, having low energy consumption, and at the same time, controlling the opening degrees of the first expansion valve 30 and the second expansion valve 60 according to the acquired first pressure information of the pipeline between the second expansion valve 60 and the gas-liquid separator 50, the ambient temperature information, and the preset target pressure, that is, controlling the opening degrees of the first expansion valve 30 and the second expansion valve 60 through the coordination of the ambient temperature and the system parameters, which can significantly improve the energy efficiency and reliability of the low-temperature heat pump air conditioner and is beneficial to improving the control accuracy.

[0071] In a feasible embodiment, the controller 90 can first determine the first proportional gain and the first integral gain according to the difference between the preset target pressure and the first pressure information, and determine the initial opening degree of the first expansion valve 30 according to the ambient temperature information. Finally, the opening degree of the first expansion valve 30 is determined according to the following corresponding relationship:

[0072] wherein, S1 represents the opening degree of the first expansion valve 30, K p1 represents the first proportional gain, P0 represents the preset target pressure, P (n) represents the first pressure information collected by the first temperature and pressure sensor 70 for the nth time, K i1 represents the first integral gain, S 10 represents the initial opening degree of the first expansion valve 30.

[0073] Exemplarily, the first temperature and pressure sensor 70 in the embodiment of the present invention can collect the first pressure information once every 1 second, the preset target pressure can be 0.3 Mpa, and the relationship between the difference between the preset target pressure and the first pressure information (P0 - P (n) ) and the first proportional gain K p1 and the first integral gain K i1 can be as shown in Table 1 below:

[0074] Table 1

[0075] <![CDATA[P0-P (n) > -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 <![CDATA[K p1 > -10 -8 -6 -3 0 2 4 5 6 <![CDATA[K i1 > -4 -3 -2 -1 0 1 2 3 4

[0076] The table 1 can be pre-stored in a memory communicatively connected to the controller 90. The controller 90 can obtain corresponding first proportional gain and first integral gain from the memory according to the difference between the preset target pressure and the first pressure information. The ambient temperature information and the initial opening degree S of the first expansion valve 10 are as shown in Table 2 below:

[0077] Table 2

[0078] Ambient temperature <![CDATA[S 20 > -10℃ 300 steps -15℃ 350 steps -20℃ 400 steps -25℃ 450 steps -30℃ 300 steps

[0079] The table 2 can be pre-stored in a memory communicatively connected to the controller 90. The controller 90 can obtain the initial opening degree of the corresponding first expansion valve 30 from the memory according to the ambient temperature information. It should be noted that when the opening degree of the first expansion valve 30 is 0 steps, it represents that the first expansion valve 30 is fully closed, and when the opening degree of the first expansion valve 30 is 640 steps, it represents that the first expansion valve 30 is fully open. To ensure that the first expansion valve 30 in the embodiments of the present invention can be applied, the maximum opening degree of the opening degree adjustment range of the first expansion valve 30 is set to 640 steps, and the minimum opening degree is set to 300 steps.

[0080] In a feasible embodiment, the controller 90 can first determine the second proportional gain and the second integral gain according to the difference between the preset target pressure and the first pressure information, and determine the initial opening degree of the second expansion valve 60 according to the ambient temperature information. Finally, the opening degree of the second expansion valve 60 is determined according to the following corresponding relationship:

[0081] Among them, S2 represents the opening degree of the second expansion valve 60, and K p2 represents the second proportional gain, P0 represents the preset target pressure, and P (n) represents the first pressure information collected by the first temperature and pressure sensor 70 for the nth time, K i2 represents the second integral gain, and S 20 represents the initial opening degree of the second expansion valve 60.

[0082] Exemplarily, the first temperature and pressure sensor 70 in the embodiments of the present invention can collect the first pressure information once every 1 second. The preset target pressure can be 0.3 Mpa. The relationship between the difference (P0 - P (n) ) between the preset target pressure and the first pressure information and the second proportional gain K p2 and the second integral gain K i2 is as shown in Table 3 below:

[0083] Table 3

[0084] <![CDATA[P0-P (n) > -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 <![CDATA[K p2 > -10 -8 -6 -3 0 2 4 5 6 <![CDATA[K i2 > -4 -3 -2 -1 0 1 2 3 4

[0085] The table 3 can be pre-stored in a memory communicatively connected to the controller 90. The controller 90 can obtain corresponding second proportional gain and second integral gain from the memory according to the difference between the preset target pressure and the first pressure information. The relationship between the ambient temperature information and the initial opening degree S of the second expansion valve 60 20 can be shown in Table 4 as follows:

[0086] Table 4

[0087] Ambient temperature <![CDATA[S 20 > -10℃ 100 steps -15℃ 150 steps -20℃ 200 steps -25℃ 250 steps -30℃ 300 steps

[0088] The table 4 can be pre-stored in a memory communicatively connected to the controller 90. The controller 90 can obtain the initial opening degree of the corresponding second expansion valve 60 from the memory according to the ambient temperature information. It should be noted that when the opening degree of the second expansion valve 60 is 0 steps, it represents that the second expansion valve 60 is fully closed, and when the opening degree of the second expansion valve 60 is 500 steps, it represents that the second expansion valve 60 is fully open. To ensure that the second expansion valve 60 in the embodiments of the present invention can be applied, the maximum opening degree of the opening degree adjustment range of the second expansion valve 60 is set to 500 steps, and the minimum opening degree is set to 100 steps.

[0089] Figure 2 FIG. is a schematic structural diagram of another low-temperature heat pump air-conditioning control system provided by the embodiments of the present invention. Referring to Figure 2 , on the basis of the above embodiments, the low-temperature heat pump air-conditioning control system in the embodiments of the present invention further includes a first switch 100, a first temperature sensor 110, and a motor 120. The output end of the first switch 100, the second input end of the second heat exchanger 40, the second output end of the second heat exchanger 40, and the input end of the first switch 100 are connected in sequence. The motor 120 is located between the second output end of the second heat exchanger 40 and the input end of the first switch 100. The first temperature sensor 110 is used to obtain the second temperature information on the second output end side of the second heat exchanger 40. The first temperature and pressure sensor 70 is further used to obtain the first temperature information of the pipeline between the second expansion valve 60 and the gas-liquid separator 50. The controller 90 is further communicatively connected to the first temperature sensor 110 and the motor 120 respectively, and is used to obtain the second temperature information, and control the stall power of the motor 120 according to the first temperature information and the second temperature information.

[0090] Exemplarily, the high-temperature refrigerant in the second heat exchanger 40 is converted into low-temperature refrigerant after releasing heat. The low-temperature refrigerant absorbs part of the heat generated by the motor 120 due to stall after passing through the motor 120 and is converted into high-temperature refrigerant. Then, the high-temperature refrigerant passes through the input end and the output end of the first switch 100 in sequence and then enters the second heat exchanger 40. It can be understood that different stall powers of the motor 120 result in different amounts of heat generated by the motor 120 due to stall. To ensure that the heat generated by the motor 120 due to stall can meet the requirement of converting the refrigerant in the low-temperature and low-pressure gas-liquid mixed state into the low-temperature and low-pressure gaseous refrigerant, the controller 90 can control the stall power of the motor 120 according to the first temperature information of the pipeline between the second expansion valve 60 and the gas-liquid separator 50 and the second temperature information of the second output end side of the second heat exchanger 40.

[0091] Exemplarily, the controller 90 can determine the stall gear of the motor 120 according to the difference between the second temperature information and the first temperature information (T2 - T1, where T2 represents the second temperature information and T1 represents the first temperature information), and finally determine the stall power of the motor 120 according to the stall gear of the motor 120. It should be noted that there are only two stall gears for the motor 120 in the embodiments of the present invention, namely the first gear and the second gear. When the stall gear of the motor 120 is the first gear, the stall power of the motor 120 is 1.7KW, and when the stall gear of the motor 120 is the second gear, the stall power of the motor 120 is 3.5KW. The difference between the second temperature information and the first temperature information and the stall gear of the motor 120 can be as shown in Table 5 below:

[0092] Table 5

[0093]

[0094] This Table 5 can be pre-stored in the memory communicatively connected to the controller 90. The controller 90 can obtain the corresponding stall gear of the motor 120 from the memory according to the difference between the second temperature information and the first temperature information, and then control the stall power of the motor 120 according to the stall gear of the motor 120.

[0095] Optionally, refer to Figure 2, the low-temperature heat pump air-conditioning control system in the embodiment of the present invention further includes a refrigerant reservoir 270. The input and output ends of the refrigerant reservoir 270 are connected to the input and output ends of the first switch 100. Under normal circumstances, the input and output ends of the first switch 100 are not connected to the output end and the input end of the first switch 100. Only when refrigerant needs to be replenished, the input and output ends of the first switch 100 will be controlled to be connected to the output end of the first switch 100, so that the refrigerant reservoir 270 can output refrigerant to the second heat exchanger 40. Only when refrigerant needs to be discharged, the input and output ends of the first switch 100 will be controlled to be connected to the input end of the first switch 100, so that the refrigerant can be discharged into the refrigerant reservoir 270 through the first switch 100. The first switch 100 can adopt an electronically controlled three-way valve. The controller 90 can be communicatively connected (electrically connected) to the control end of the first switch 100 and can control the on-off state of the first switch 100 according to the refrigerant demand and the working state of the low-temperature heat pump air conditioner.

[0096] Optionally, referring to Figure 2 , the low-temperature heat pump air-conditioning control system in the embodiment of the present invention further includes a first electronic water pump 240, a second electronic water pump 250 and a third switch 260. The first electronic water pump 240 is located between the output end of the first switch 100 and the first input end of the third switch 260. The second electronic water pump 250 is located between the first output end of the third switch 260 and the second input end of the second heat exchanger 40. The second output end of the second heat exchanger 40 is connected to the second input end of the third switch 260. The second output end of the third switch 260 is connected to the input end of the motor 120. The output end of the motor 120 is connected to the input end of the first switch 100. It should be noted that when the low-temperature heat pump is in the working state, the first input end and the first output end of the third switch 260 are connected, and the second input end and the second output end of the third switch 260 are connected. The first electronic water pump 240 and the second electronic water pump 250 are in the working state and can drive the refrigerant to circulate between the second heat exchanger 40, the third switch 260, the motor 120 and the first switch 100. The controller 90 is also communicatively connected (electrically connected) to the control end of the first electronic water pump 240, the control end of the second electronic water pump 250 and the control end of the third switch 260 respectively, and can control the start-stop state of the first electronic water pump 240, the start-stop state of the second electronic water pump 250 and the on-off state of the third switch 260 according to the working state of the low-temperature heat pump air conditioner.

[0097] Figure 3 is a schematic structural diagram of another low-temperature heat pump air-conditioning control system provided by the embodiment of the present invention. Referring to Figure 3, on the basis of the above embodiments, the low-temperature heat pump air-conditioning system in the embodiments of the present invention further includes a heater 130. The heater 130 is located between the motor 120 and the input end of the first switch 100. The controller 90 is also communicatively connected to the heater 130 and is configured to control the power of the heater 130 according to the first temperature information, the second temperature information, and the locked-rotor power.

[0098] It can be understood that in the low-temperature heat pump air conditioner in the embodiments of the present invention, the locked-rotor power of the motor 120 reaches the maximum, but the heat generated by the motor 120 due to blocking still cannot meet the demand for converting the refrigerant in the low-temperature and low-pressure gas-liquid mixed state into the refrigerant in the low-temperature and low-pressure gaseous state. To ensure the smooth progress of heating, a heater 130 can be provided between the motor 120 and the input end of the first switch 100 to heat the coolant input into the second heat exchanger 40. Specifically, the power of the heater 130 can be controlled according to the first temperature information of the pipeline between the second expansion valve 60 and the gas-liquid separator 50, the second temperature information on the second output end side of the second heat exchanger 40, and the locked-rotor power of the motor 120.

[0099] Exemplarily, the controller 90 can control the heater 130 to start after the locked-rotor power of the motor 120 reaches the maximum power and lasts for more than a first preset time (for example, one minute), then determine the third proportional gain and the third integral gain according to the difference between the second temperature information and the first temperature information, and finally determine the power of the heater 130 according to the following corresponding relationship:

[0100] wherein, P1 represents the power of the heater 130, K p3 represents the third proportional gain, T2 (n) represents the second temperature information collected by the second temperature sensor 110 for the nth time, T1 (n) represents the first temperature information collected by the first temperature and pressure sensor 70 for the nth time, K i3 represents the third integral gain.

[0101] The first temperature and pressure sensor 70 in the embodiments of the present invention can collect the first temperature information every 1 second, the first temperature sensor 110 can collect the second temperature information every 1 second, and the difference between the second temperature information and the first temperature information (T2 (n) -T1 (n) ) and the relationship between the third proportional gain K p3 and the third integral gain K i3 can be as shown in Table 6 below:

[0102] Table 6

[0103] <![CDATA[T2 (n) -T1 (n) > 6 7 8 9 10 11 12 13 14 <![CDATA[K p3 > 20 15 10 5 0 -5 -10 -15 -20 <![CDATA[K i3 > 4 3 2 1 0 -2 -3 -4 -5

[0104] The table 6 can be pre-stored in a memory communicatively connected to the controller 90, and the controller 90 can obtain the corresponding third proportional gain and third integral gain from the memory according to the difference between the second temperature information and the first temperature information.

[0105] Figure 4 FIG. is a schematic structural diagram of another low-temperature heat pump air-conditioning control system provided by an embodiment of the present invention. Refer to Figure 4 , on the basis of the above embodiment, the low-temperature heat pump air-conditioning system in the embodiment of the present invention further includes a heater 130 and a second temperature sensor 140. The heater 130 is located between the motor 120 and the input end of the first switch 100. The second temperature sensor 140 is configured to obtain third temperature information of the pipeline between the heater 130 and the input end of the first switch 100. The controller 90 is also communicatively connected to the second temperature sensor 140 and the heater 130 respectively, and is configured to obtain the third temperature information and control the start-stop state of the motor 120 stalling and / or the start-stop state of the heater 130 according to the third temperature information.

[0106] Exemplarily, when the third temperature information of the pipeline between the heater 130 and the input end of the first switch 100 is relatively high, the motor 120 does not stall and the heater 130 does not start, which can meet the requirement of converting the refrigerant in the low-temperature and low-pressure gas-liquid mixed state into the low-temperature and low-pressure gaseous refrigerant. To reduce the energy consumption of the entire low-temperature heat pump air conditioner, the heater 130 and / or the motor 120 stalling can be controlled to stop working.

[0107] Specifically, when the third temperature information of the pipeline between the heater 130 and the input end of the first switch 100 is greater than the first preset temperature (e.g., 50 °C) and the duration exceeds the second preset time (e.g., 5 seconds), first control the power of the heater 130 to drop to 0 and stop working. After the heater 130 stops working for a time exceeding the third preset time (e.g., 1 minute), if the third temperature information of the pipeline between the heater 130 and the input end of the first switch 100 is still greater than the first preset temperature (e.g., 50 °C) and the duration exceeds the second preset time (e.g., 5 seconds), the motor 120 will be controlled to stop stalling. When the third temperature information of the pipeline between the heater 130 and the input end of the first switch 100 is less than the second preset temperature (e.g., 45 °C) and the duration exceeds the second preset time (e.g., 5 seconds), first control the motor 120 to start stalling. After the motor 120 starts stalling for a time exceeding the third preset time (e.g., 1 minute), if the third temperature information of the pipeline between the heater 130 and the input end of the first switch 100 is still less than the second preset temperature (e.g., 45 °C) and the duration exceeds the second preset time (e.g., 5 seconds), the heater 130 will be controlled to start. It should be noted that to avoid the motor 120 from stalling and the heater 130 from starting and stopping repeatedly and frequently due to the change of the third temperature information when the first preset temperature and the second preset temperature are the same, it is necessary to set the first preset temperature different from the second preset temperature, and the first preset temperature is greater than the second preset temperature. The controller 90 can also control the heater 130 to stop working and the motor 120 to stop stalling when the third temperature information is in an intermediate state (e.g., the third temperature information is greater than or equal to 45 °C and less than or equal to 50 °C).

[0108] Continue to refer to Figure 4 , the low-temperature heat pump air-conditioning system further includes a battery 150, a second switch 160, a third temperature sensor 170, and a fourth temperature sensor 180. The battery 150 includes a first end and a second end. The input end of the second switch 160 is connected to the second output end of the second heat exchanger 40. The first output end of the second switch 160 is connected to the first end. The second output end of the second switch 160 is respectively connected to the input end and the second end of the first switch 160. The third temperature sensor 170 is used to obtain the fourth temperature information on the first end side of the battery 150. The fourth temperature sensor 180 is used to obtain the fifth temperature information on the second end side of the battery 150. The controller 90 is also respectively communicatively connected to the second switch 160, the third temperature sensor 170, and the fourth temperature sensor 180, and is used to obtain the fourth temperature information and the fifth temperature information, and control the state of the second switch 160 according to the third temperature information, the fourth temperature information, and the fifth temperature information.

[0109] The battery 150 in the embodiment of the present invention may adopt a lithium-ion battery. The optimal operating temperature of a lithium-ion battery is 0°C to 35°C. In a low-temperature environment, the activity of lithium ions will be reduced, the discharge capacity of the lithium-ion battery will become weaker, and the usage time will be shortened. To ensure that the too low temperature of the battery 150 will not affect the discharge capacity of the battery 150, it is necessary to control the battery 150 to maintain within a suitable temperature range, and the battery 150 needs to be heated. Specifically, the controller 90 can determine whether to heat the battery 150 according to the temperature information on both sides of the battery 150 (i.e., the fourth temperature information and the fifth temperature information) obtained. If it is necessary to heat the battery 150, it will control the input end and the first output end of the second switch 160 to be connected. It can be understood that when the input end and the first output end of the second switch 160 are connected, the battery 150 will absorb heat, thereby reducing the temperature of the coolant input to the motor 120. If the temperature of the coolant input to the second heat exchanger 40 becomes too low due to the heat absorption of the battery 150, that is, the third temperature information of the pipeline between the heater 130 and the input end of the first switch 100 is too low, it is necessary to adjust the amount of coolant input to the battery 150 by controlling the opening degree between the input end and the first output end of the second switch 160.

[0110] Reference Figure 1 , Figure 2 , Figure 3 and Figure 4 , the low-temperature heat pump air-conditioning system further includes an air outlet temperature sensor 190, an indoor temperature sensor 200, and a light intensity sensor 210. The air outlet temperature sensor 190 is used to obtain the air outlet temperature information. The indoor temperature sensor 200 is used to obtain the indoor temperature information. The light intensity sensor 210 is used to obtain the light intensity information. The controller 90 is respectively communicatively connected to the air outlet temperature sensor 190, the indoor temperature sensor 200, and the light intensity sensor 210, and is used to obtain the air outlet temperature information, the indoor temperature information, and the light intensity information, and control the rotation speed and start-stop state of the compressor 10 according to the air outlet temperature information, the indoor temperature information, the light intensity information, and the ambient temperature information.

[0111] The rotation speed of the compressor 10 will affect the air outlet temperature information, and thus affect the indoor temperature information. To achieve precise control of the indoor temperature information, it is necessary to control the rotation speed and start-stop state of the compressor 10 according to the air outlet temperature information and the indoor temperature information. It can be understood that the light intensity information and the ambient temperature information will affect the energy efficiency of the compressor 10, and thus affect the control of the indoor temperature information. To further improve the control accuracy of the indoor temperature information, the rotation speed and start-stop state of the compressor 10 can be controlled according to the air outlet temperature information, the indoor temperature information, the light intensity information, and the ambient temperature information.

[0112] Exemplarily, the controller 90 may first determine the indoor set temperature according to the acquired indoor temperature information, light intensity information, and ambient temperature information, and finally control the start / stop state of the compressor 10 according to the outlet air temperature information, and control the rotation speed of the compressor 10 according to the indoor set temperature, outlet air temperature information, and ambient temperature information when the compressor 10 is in the start state.

[0113] Specifically, when the outlet air temperature information is greater than or equal to a third preset temperature (for example, 70 °C) and the duration reaches a fourth preset time (for example, 10 seconds), the controller 90 turns off the compressor 10. If the outlet air temperature information is less than a fourth preset temperature (for example, 65 °C) and the duration reaches the fourth preset time (for example, 10 seconds), the controller 90 turns on the compressor 10.

[0114] The controller 90 may determine the indoor set temperature according to the indoor temperature information, light intensity information, ambient temperature information, and the following corresponding relationship:

[0115] T s1 = 25 - 2×(A×(T3 - 25) + B×(T4 - 25) + C×T5 - D×(T s0 - 25));

[0116] Wherein, T s1 represents the indoor set temperature, T3 represents the indoor temperature information, T4 represents the ambient temperature information, T5 represents the compensation temperature information corresponding to the light intensity information, and T s0 represents the set temperature (i.e., the temperature set by the user), and A, B, C, and D represent the coefficients of the preset thermal management model.

[0117] When the compressor 10 is in the start state, the controller 90 may first determine the fourth proportional gain and the fourth integral gain according to the difference between the outlet air temperature information and the indoor set temperature, and determine the initial rotation speed of the compressor 10 according to the ambient temperature information. Finally, the rotation speed of the compressor 10 is determined according to the following corresponding relationship:

[0118]

[0119] Wherein, V1 represents the rotation speed of the compressor 10, K p4 represents the fourth proportional gain, T 6(n) represents the outlet air temperature information collected by the outlet air temperature sensor 190 for the nth time, K i4 represents the third integral gain, and V 10 represents the initial rotation speed of the compressor 10.

[0120] In the embodiment of the present invention, the outlet air temperature sensor 190 may collect once every 1 second, and the difference between the outlet air temperature information and the indoor set temperature (T 6(n) - T s1 ) and the fourth proportional gain Kp4 and the fourth integral gain K i4 The relationship is as shown in Table 7 below:

[0121] Table 7

[0122] <![CDATA[T 6(n) -T s1 > -6 -4 -2 0 2 4 6 <![CDATA[K p4 > 45 35 25 0 -25 -30 -35 <![CDATA[K i4 > 10 8 5 0 -5 -5 -5

[0123] This Table 7 can be pre-stored in a memory communicatively connected to the controller 90. The controller 90 can obtain the corresponding fourth proportional gain and fourth integral gain from the memory according to the difference between the air outlet temperature information and the indoor set temperature.

[0124] The relationship between the ambient temperature information and the initial speed V of the compressor 10 10 is as shown in Table 8 below:

[0125] Table 8

[0126] Ambient temperature <![CDATA[V 10 > -10℃ 800 rpm -15℃ 800 rpm -20℃ 1000 rpm -25℃ 1500 rpm -30℃ 1800 rpm

[0127] This Table 8 can be pre-stored in a memory communicatively connected to the controller 90. The controller 90 can obtain the corresponding initial speed of the compressor 10 from the memory according to the ambient temperature information.

[0128] Reference Figure 1 、 Figure 2 、 Figure 3 and Figure 4 In addition, the low-temperature heat pump air-conditioning system further includes a second temperature and pressure sensor 220 and a first pressure sensor 230. The second temperature and pressure sensor 220 is used to obtain the suction pressure information of the compressor 10. The first pressure sensor 230 is used to obtain the discharge pressure information of the compressor 10. The controller 90 is communicatively connected to the second temperature and pressure sensor 220 and the first pressure sensor 230 respectively, and is used to obtain the suction pressure information and the discharge pressure information, and adjust the speed and start-stop state of the compressor 10 according to the suction pressure information and the discharge pressure information.

[0129] It is understandable that too low suction pressure information of the compressor 10, too high discharge pressure information of the compressor 10, or too high compression ratio of the compressor 10 (i.e., discharge pressure information of the compressor 10 / suction pressure information of the compressor) may cause damage to the compressor 10. To avoid this situation, the controller 90 adjusts the rotational speed of the compressor 10 according to the acquired suction pressure information and discharge pressure information to ensure that the suction pressure information of the compressor 10 is not too low, the discharge pressure information of the compressor 10 is not too high, or the compression ratio of the compressor 10 is not too high. Specifically, if P2 (discharge pressure information of the compressor 10) > 3.0 MPa, the compressor 10 is directly shut down, and the compressor 10 will be restarted only when the user needs to start the low-pressure heat pump air conditioner. During the operation of the compressor 10, if the compression ratio of the compressor 10 (P2 / P3, where P3 represents the suction pressure information of the compressor 10) ≥ 13 or 2.5 MPa ≤ P2 ≤ 3.0 MPa, the rotational speed of the compressor 10 will be controlled to decrease by 200 rpm, and after pausing for the fifth preset time, the suction pressure information and discharge pressure information of the compressor 10 will be acquired again. It should be noted that the second temperature and pressure sensor 220 can collect the suction pressure information of the compressor 10 once every 200 ms and take the average value of the 5 times of collection within the fifth preset time range as the suction pressure information of the compressor 10 participating in the control of the compressor rotational speed. The first pressure sensor 230 can collect the discharge pressure information of the compressor 10 once every 200 ms and take the average value of the 5 times of collection within the fifth preset time range as the discharge pressure information of the compressor 10 participating in the control of the compressor rotational speed. If the acquired compression ratio of the compressor 10 (P2 / P3) ≥ 13 or the discharge pressure information P2 of the compressor 10 ≥ 2.5 MPa, the rotational speed of the compressor 10 will be controlled to continue to decrease by 200 rpm, and the above steps will be executed cyclically until the compressor 10 reaches the lowest rotational speed (for example, 1200 rpm). If when the compressor 10 reaches the lowest rotational speed, the acquired compression ratio of the compressor 10 (P2 / P3) ≥ 13 or the discharge pressure information P2 of the compressor 10 ≥ 2.5 MPa, the compressor 10 will be shut down. If 10 ≤ (P2 / P3) < 13 or 2.3 MPa ≤ P2 < 2.5 MPa appears during the process of decreasing the rotational speed of the compressor 10, the rotational speed of the compressor 10 will be maintained unchanged. If P2 < 2.3 Mpa and the compression ratio (P2 / P3) < 10 appear during the process of decreasing the rotational speed of the compressor 10, the rotational speed of the compressor 10 will be controlled to increase by 100 rpm on the premise that it does not exceed the highest rotational speed.

[0130] Optionally, to further protect the compressor 10, it is also necessary to set the maximum rotational speed of the compressor 10 as follows: when P3 < 0.3 Mpa and P2 < 1.8 Mpa, the maximum rotational speed of the compressor 10 is set to 2000 rpm; when P3 < 0.3 Mpa and 1.8 Mpa ≤ P2 ≤ 2.7 Mpa, the maximum rotational speed of the compressor 10 is set to 9000 rpm; when 0.3 Mpa ≤ P3 ≤ 0.6 Mpa and P2 < ((-7 / 2)×P3 + 3.2) Mpa, the maximum rotational speed of the compressor 10 is set to 2000 rpm; when 0.3 Mpa ≤ P3 ≤ 0.6 Mpa and ((-7 / 2)×P3 + 3.2) Mpa ≤ P2 < 2.7 Mpa, the maximum rotational speed of the compressor 10 is set to 9000 rpm.

[0131] The embodiment of the present invention also provides a control method for a low-temperature heat pump air conditioner. This control method for a low-temperature heat pump air conditioner is applied to the low-temperature heat pump air conditioner control system provided in the above embodiment of the present invention. Figure 5 As shown in the flowchart of a control method for a low-temperature heat pump air conditioner provided by an embodiment of the present invention, refer to Figure 5 , the control method for a low-temperature heat pump air conditioner in the embodiment of the present invention includes:

[0132] S101. Obtain the first pressure information and the ambient temperature information.

[0133] Exemplarily, refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 , the controller 90 is communicatively connected to the first temperature and pressure sensor 70, and the first pressure information of the pipeline between the second expansion valve 60 and the gas-liquid separator 50 can be obtained through the first temperature and pressure sensor 70. The controller 90 is communicatively connected to the ambient temperature sensor 80, and the ambient temperature information can be obtained through the ambient temperature sensor 80.

[0134] S102. Control the opening degrees of the first expansion valve and the second expansion valve according to the first pressure information, the ambient temperature information, and the preset target pressure.

[0135] As a feasible implementation manner, controlling the opening degree of the first expansion valve according to the first pressure information, the ambient temperature information, and the preset target pressure includes: determining the first proportional gain and the first integral gain according to the difference between the preset target pressure and the first pressure information; determining the initial opening degree of the first expansion valve according to the ambient temperature information; determining the opening degree of the first expansion valve according to the following corresponding relationship:

[0136]

[0137] wherein, S1 represents the opening degree of the first expansion valve, K p1 represents the first proportional gain, P0 represents the preset target pressure, P(n) represents the first pressure information collected by the first temperature and pressure sensor for the nth time, K i1 represents the first integral gain, S 10 represents the initial opening degree of the first expansion valve.

[0138] As a feasible implementation manner, controlling the opening degree of the second expansion valve according to the first pressure information, the ambient temperature information, and the preset target pressure includes: determining the second proportional gain and the second integral gain according to the difference between the preset target pressure and the first pressure information; determining the initial opening degree of the second expansion valve according to the ambient temperature information; determining the opening degree of the second expansion valve according to the following corresponding relationship:

[0139]

[0140] wherein, S2 represents the opening degree of the second expansion valve, K p2 represents the second proportional gain, P0 represents the preset target pressure, P (n) represents the first pressure information collected by the first temperature and pressure sensor for the nth time, K i2 represents the second integral gain, S 20 represents the initial opening degree of the second expansion valve.

[0141] In the embodiment of the present invention, a second expansion valve 60 is arranged between the input end of the first heat exchanger 20 and the input end of the gas-liquid separator 50, and the opening degree of the second expansion valve 60 is controlled according to the first pressure information, the ambient temperature information, and the preset target pressure of the pipeline between the second expansion valve 60 and the gas-liquid separator 50, that is, controlling a part of the high-temperature and high-pressure refrigerant gas (hot gas) discharged by the compressor 10 to bypass to the input end side of the compressor 10, avoiding faults caused by pressure imbalance of the low-temperature heat pump air conditioner at low temperatures, being beneficial to improving the heating continuity, increasing the heating speed, without the need to add a high-power heater to achieve low-temperature heating, having low energy consumption, and at the same time controlling the opening degrees of the first expansion valve 30 and the second expansion valve 60 according to the first pressure information, the ambient temperature information, and the preset target pressure of the pipeline between the second expansion valve 60 and the gas-liquid separator 50, that is, controlling the opening degrees of the first expansion valve 30 and the second expansion valve 60 through the coordination of the ambient temperature and system parameters, can significantly improve the energy efficiency and reliability of the low-temperature heat pump air conditioner, and is beneficial to improving the control accuracy.

[0142] Figure 6 is a flowchart of another low-temperature heat pump air conditioner control method provided by the embodiment of the present invention, Figure 6 The shown embodiment enriches the process of the low-temperature heat pump air conditioner control method. Referring to Figure 6 , the low-temperature heat pump air conditioner control method in the embodiment of the present invention further includes:

[0143] S201. Obtain the first pressure information and the ambient temperature information.

[0144] S202. Control the opening degrees of the first expansion valve and the second expansion valve according to the first pressure information, the ambient temperature information, and a preset target pressure.

[0145] S203. Obtain the outlet air temperature information, the indoor temperature information, and the light intensity information.

[0146] Exemplarily, referring to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 , the controller 90 is communicatively connected to the outlet air temperature sensor 190, the indoor temperature sensor 200, and the light intensity sensor 210 respectively. The outlet air temperature information can be obtained through the outlet air temperature sensor 190, the indoor temperature information can be obtained through the indoor temperature sensor 200, and the light intensity information can be obtained through the light intensity sensor 210.

[0147] S204. Control the rotation speed and the start / stop state of the compressor according to the outlet air temperature information, the indoor temperature information, the light intensity information, and the ambient temperature information.

[0148] Exemplarily, referring to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 , the controller 90 can first determine the indoor set temperature according to the obtained indoor temperature information, light intensity information, and ambient temperature information, and finally control the start / stop state of the compressor 10 according to the outlet air temperature information, and control the rotation speed of the compressor 10 according to the indoor set temperature, the outlet air temperature information, and the ambient temperature information when the compressor 10 is in the start state.

[0149] In the embodiment of the present invention, by setting to be able to control the rotation speed and the start / stop state of the compressor according to the obtained outlet air temperature information, indoor temperature information, light intensity information, and ambient temperature information, that is, to control the rotation speed and the start / stop state of the compressor through the coordination of the light intensity information, the ambient temperature information, and the system parameters, and then control the indoor temperature, which is beneficial to improving the control accuracy.

[0150] The above specific implementation manners do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A low-temperature heat pump air-conditioning control system, characterized in that, It includes a compressor, a first heat exchanger, a first expansion valve, a second heat exchanger, a gas-liquid separator, a second expansion valve, a first temperature and pressure sensor, an ambient temperature sensor, and a controller; The output end of the compressor, the input end of the first heat exchanger, the output end of the first heat exchanger, the input end of the first expansion valve, the output end of the first expansion valve, the first input end of the second heat exchanger, the first output end of the second heat exchanger, the input end of the gas-liquid separator, the output end of the gas-liquid separator, and the input end of the compressor are connected in sequence; The second expansion valve is connected between the input end of the gas-liquid separator and the input end of the first heat exchanger; The first temperature and pressure sensor is used to obtain the first pressure information of the pipeline between the second expansion valve and the gas-liquid separator; The ambient temperature sensor is used to obtain the ambient temperature information; The controller is respectively communicatively connected with the first expansion valve, the second expansion valve, the first temperature and pressure sensor, and the ambient temperature sensor, and is used to obtain the first pressure information and the ambient temperature information, and control the opening degrees of the first expansion valve and the second expansion valve according to the first pressure information, the ambient temperature information, and a preset target pressure.

2. The low-temperature heat pump air-conditioning control system according to claim 1, wherein The low-temperature heat pump air-conditioning control system further includes a first switch, a first temperature sensor, and a motor; The output end of the first switch, the second input end of the second heat exchanger, the second output end of the second heat exchanger, and the input end of the first switch are connected in sequence; The motor is located between the second output end of the second heat exchanger and the input end of the first switch; The first temperature sensor is used to obtain the second temperature information on the second output end side of the second heat exchanger; The first temperature and pressure sensor is further used to obtain the first temperature information of the pipeline between the second expansion valve and the gas-liquid separator; The controller is further respectively communicatively connected with the first temperature sensor and the motor, and is used to obtain the second temperature information, and control the locked-rotor power of the motor according to the first temperature information and the second temperature information.

3. The low-temperature heat pump air-conditioning control system according to claim 2, wherein The low-temperature heat pump air-conditioning system further includes a heater; The heater is located between the motor and the input end of the first switch; The controller is further communicatively connected with the heater, and is used to control the power of the heater according to the first temperature information, the second temperature information, and the locked-rotor power.

4. The low-temperature heat pump air-conditioning control system according to claim 2, wherein The low-temperature heat pump air-conditioning system further includes a heater and a second temperature sensor; The heater is located between the motor and the input end of the first switch; The second temperature sensor is used to obtain the third temperature information of the pipeline between the heater and the input end of the first switch; The controller is further respectively communicatively connected with the second temperature sensor and the heater, and is used to obtain the third temperature information, and control the start-stop state of the motor locked-rotor and / or the start-stop state of the heater according to the third temperature information.

5. The low-temperature heat pump air-conditioning control system according to claim 4, characterized in that The low-temperature heat pump air-conditioning system further includes a battery, a second switch, a third temperature sensor, and a fourth temperature sensor; the battery includes a first end and a second end; The input end of the second switch is connected to the second output end of the second heat exchanger, the first output end of the second switch is connected to the first end, and the second output end of the second switch is respectively connected to the input end of the first switch and the second end; The third temperature sensor is used to obtain the fourth temperature information on the first end side of the battery; The fourth temperature sensor is used to obtain the fifth temperature information on the second end side of the battery; The controller is also respectively communicatively connected to the second switch, the third temperature sensor and the fourth temperature sensor, and is used to obtain the fourth temperature information and the fifth temperature information, and control the state of the second switch according to the third temperature information, the fourth temperature information and the fifth temperature information.

6. The low-temperature heat pump air-conditioning control system according to claim 1, characterized in that, The low-temperature heat pump air-conditioning system further includes an air outlet temperature sensor, an indoor temperature sensor and a light intensity sensor; The air outlet temperature sensor is used to obtain the air outlet temperature information; the indoor temperature sensor is used to obtain the indoor temperature information; the light intensity sensor is used to obtain the light intensity information; The controller is respectively communicatively connected to the air outlet temperature sensor, the indoor temperature sensor and the light intensity sensor, and is used to obtain the air outlet temperature information, the indoor temperature information and the light intensity information, and control the rotation speed and start-stop state of the compressor according to the air outlet temperature information, the indoor temperature information, the light intensity information and the ambient temperature information.

7. The low-temperature heat pump air-conditioning control system according to claim 6, wherein, The low-temperature heat pump air-conditioning system further includes a second temperature and pressure sensor and a first pressure sensor; The second temperature and pressure sensor is used to obtain the suction pressure information of the compressor; The first pressure sensor is used to obtain the discharge pressure information of the compressor; The controller is respectively communicatively connected to the second temperature and pressure sensor and the first pressure sensor, and is used to obtain the suction pressure information and the discharge pressure information, and adjust the rotation speed and start-stop state of the compressor according to the suction pressure information and the discharge pressure information.

8. A control method for a low-temperature heat pump air conditioner, applied to the low-temperature heat pump air conditioner control system according to any one of claims 1-7, characterized in that, The low-temperature heat pump air-conditioning control method includes: Obtaining the first pressure information and the ambient temperature information; Controlling the opening degrees of the first expansion valve and the second expansion valve according to the first pressure information, the ambient temperature information and a preset target pressure.

9. The low-temperature heat pump air conditioner control method according to claim 8, wherein, Controlling the opening degree of the first expansion valve according to the first pressure information, the ambient temperature information and the preset target pressure includes: Determining a first proportional gain and a first integral gain according to the difference between the preset target pressure and the first pressure information; Determining the initial opening degree of the first expansion valve according to the ambient temperature information; Determining the opening degree of the first expansion valve according to the following corresponding relationship: Among them, S1 represents the opening degree of the first expansion valve, K p1 represents the first proportional gain, P0 represents the preset target pressure, P (n) represents the first pressure information collected by the first temperature and pressure sensor for the nth time, K i1 represents the first integral gain, S 10 represents the initial opening degree of the first expansion valve; Controlling the opening degree of the second expansion valve according to the first pressure information, the ambient temperature information and the preset target pressure includes: Determining a second proportional gain and a second integral gain according to the difference between the preset target pressure and the first pressure information; Determining the initial opening degree of the second expansion valve according to the ambient temperature information; Determining the opening degree of the second expansion valve according to the following corresponding relationship: Among them, S2 represents the opening degree of the second expansion valve, K p2 represents the second proportional gain, P0 represents the preset target pressure, P (n) represents the first pressure information collected by the first temperature and pressure sensor for the nth time, K i2 represents the second integral gain, S 20 represents the initial opening degree of the second expansion valve.

10. The low-temperature heat pump air conditioner control method according to claim 8, characterized in that, The low-temperature heat pump air-conditioning control method further includes: Obtain the air outlet temperature information, indoor temperature information, and light intensity information; Control the rotation speed and start / stop state of the compressor according to the air outlet temperature information, the indoor temperature information, the light intensity information, and the ambient temperature information.

Images