Air conditioning system and control method thereof

Abstract

The invention relates to the technical field of air conditioners, in particular to an air conditioning system and a control method of the air conditioning system.The air conditioning system comprises an outlet of a compressor, a first passage of a four-way valve, a condenser, a first expansion valve, an evaporator, a second passage of the four-way valve and an inlet of the compressor which are sequentially communicated to form a refrigerating loop; and the first branch is communicated between the outlet of the compressor and the inlet of the compressor. The first branch is introduced to increase the exhaust temperature of the compressor, the operation that the frequency of the compressor needs to be increased and the opening degree of the electronic expansion valve needs to be reduced when the exhaust temperature of the air conditioning system is increased is replaced, the frequency increase of the compressor is small, and the higher refrigerating capacity, the higher reliability of the compressor and the higher stability of the air conditioning system are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and particularly to an air conditioning system and a control method thereof. Background Art

[0002] Generally, an air conditioner has insufficient cooling capacity under high temperature conditions (such as above 50°C) during refrigeration. Because when the outdoor temperature is too high, the heat exchange capacity of the condenser decreases, resulting in a higher temperature and pressure of the refrigerant entering the room. This leads to a smaller heat exchange temperature difference between the indoor refrigerant and the air, and a reduced heat absorption space for the indoor-side refrigerant, thus causing a decrease in indoor cooling capacity.

[0003] If we want to improve the cooling capacity of an air conditioner under high temperature conditions, we need to increase the heat exchange amount on the outdoor side, that is, increase the exhaust temperature, thereby increasing the condensation temperature and the heat exchange temperature difference on the outdoor side. Usually, when an air conditioning system increases the exhaust temperature, it can increase the compressor frequency and reduce the opening degree of the electronic expansion valve. However, increasing the frequency has a greater impact on the reliability of the compressor under high temperature conditions. The maximum frequency that the compressor can withstand under high temperature conditions is lower than that under low temperature conditions. At the same time, closing the valve is equivalent to reducing the mass flow rate of the refrigerant entering the indoor unit, which will also affect the heat exchange on the indoor side. Summary of the Invention

[0004] The present invention provides an air conditioning system and a control method thereof to solve one of the defects in the prior art. By introducing a first branch to increase the compressor exhaust temperature, the present invention replaces the operations of increasing the compressor frequency and reducing the opening degree of the electronic expansion valve when the air conditioning system increases the exhaust temperature. The frequency increase of the compressor is small, ensuring higher cooling capacity, the reliability of the compressor, and the stability of the air conditioning system.

[0005] The present invention provides an air conditioning system, including: The outlet of the compressor, the first passage of the four-way valve, the condenser, the first expansion valve, the evaporator, the second passage of the four-way valve, and the inlet of the compressor are sequentially connected to form a refrigeration circuit; A first branch, which is connected between the outlet of the compressor and the inlet of the compressor.

[0006] According to the air conditioning system provided by the present invention, the first branch is provided with a second expansion valve.

[0007] According to the air conditioning system provided by the present invention, it further includes: A second branch, which is connected between the inlet of the second passage of the four-way valve and the inlet of the first expansion valve, and the second branch is adapted to exchange heat with an electronic control component.

[0008] According to the air conditioning system provided by the present invention, the second branch is provided with a heat exchange component.

[0009] An air conditioning system provided by the present invention, a valve body is provided in the second branch.

[0010] An air conditioning system provided by the present invention further includes: A temperature sensor, which is adapted to detect the condensation temperature of the refrigerant in the condenser.

[0011] In an air conditioning system provided by the present invention, a first stop valve is provided on the pipeline where the first expansion valve is communicated with the evaporator; A second stop valve is provided on the pipeline where the evaporator is communicated with the second passage of the four-way valve.

[0012] The present invention also provides a control method for an air conditioning system, which is applied to the air conditioning system as described above, and includes: Obtain the outdoor temperature; Determine that the outdoor temperature is higher than the set outdoor temperature, open the second expansion valve, and connect the inlet of the compressor to the liquid inlet through the first branch; Adjust the opening degree of the second expansion valve until the exhaust temperature of the compressor reaches the set exhaust temperature.

[0013] A control method for an air conditioning system provided by the present invention further includes: Adjust the opening degree of the first expansion valve until the condensation temperature of the refrigerant reaches the set condensation temperature.

[0014] In a control method for an air conditioning system provided by the present invention, the refrigerant flow rate in the first branch at the maximum opening degree of the second expansion valve is less than the refrigerant flow rate of the compressor into the four-way valve.

[0015] The air conditioning system provided by the present invention mainly consists of a compressor, a four-way valve, a condenser, a first expansion valve, an evaporator and a first branch. When the air conditioning system turns on the cooling mode under the condition of a lower external environment temperature or a normal temperature, the outlet of the compressor discharges high-temperature and high-pressure gaseous refrigerant, the first passage of the four-way valve is connected, and the refrigerant enters the heat release passage of the condenser through the first passage of the four-way valve. The refrigerant exchanges heat with the refrigerant in the heat absorption passage in the heat release passage of the condenser. The refrigerant condenses and cools down, flows out of the condenser and then enters the first expansion valve. After being depressurized and cooled again by the first expansion valve, it enters the heat absorption passage of the evaporator. The refrigerant exchanges heat with the air in the heat absorption passage and the heat release passage of the evaporator to cool the air, and then the air conditioning completes the cooling work on the indoor space. The second passage of the four-way valve is connected, and the refrigerant flows out of the evaporator and returns to the inlet of the compressor through the second passage of the four-way valve and enters the compressor. In this cooling mode, no refrigerant flows through the first branch.

[0016] When the air - conditioning system turns on the cooling mode under the condition of a relatively high external environmental temperature, while ensuring that the compressor, four - way valve, condenser, first expansion valve, and evaporator form a refrigeration circuit for refrigeration operation, the outlet and inlet of the compressor are connected through the first branch. This is equivalent to constructing a diversion branch at the outlet of the compressor, dividing the refrigerant discharged from the outlet of the compressor into two parts. One part flows through the four - way valve and then to the condenser to enter the refrigeration circuit, and the other part returns to the inlet of the compressor through the first branch and enters the compressor.

[0017] Thus, the high - temperature refrigerant in the first branch at the inlet of the compressor converges with the low - temperature refrigerant flowing out of the evaporator and flowing out of the first passage of the four - way valve, increasing the overall temperature of the refrigerant returning to the compressor. This further increases the exhaust temperature at the outlet of the compressor, thereby increasing the condensation temperature of the refrigerant at the condenser, increasing the heat - transfer temperature difference on the outdoor side, improving the refrigeration capacity of the air - conditioning system under high - temperature conditions, and ensuring the indoor - side heat - transfer and refrigeration effect under high - temperature conditions. Compared with the traditional air - conditioning system, the present invention introduces the first branch to increase the compressor exhaust temperature, replacing the operations of increasing the compressor frequency and reducing the opening degree of the electronic expansion valve when the air - conditioning system increases the exhaust temperature. The frequency increase of the compressor is relatively small, ensuring higher refrigeration capacity, the reliability of the compressor, and the stability of the air - conditioning system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following - described drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of the liquid distributor provided by the embodiment of the present invention.

[0020] REFERENCE SIGNS 100, compressor; 200, four - way valve; 210, first passage; 220, second passage; 300, condenser; 400, first expansion valve; 500, evaporator; 510, first stop valve; 520, second stop valve; 600, first branch; 610, second expansion valve; 700, second branch; 800, temperature sensor; 900, electronic control component; 910, first pipeline; 920, second pipeline; 930, third pipeline; 940, fourth pipeline; 950, fifth pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] To make the objectives, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the accompanying drawings in the present invention. Apparently, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts belong to the scope of protection of the present invention.

[0022] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0023] In the description of the embodiments of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0024] In the embodiments of the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0025] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0026] As Figure 1 shown, an air-conditioning system provided by an embodiment of the present invention includes an outlet of a compressor 100, a first passage 210 of a four-way valve 200, a condenser 300, a first expansion valve 400, an evaporator 500, a second passage 220 of the four-way valve 200, and an inlet of the compressor 100, which are connected in sequence to form a refrigeration circuit; and a first branch 600, and the first branch 600 is connected between the outlet of the compressor 100 and the inlet of the compressor 100.

[0027] The air-conditioning system of the embodiment of the present invention mainly consists of a compressor 100, a four-way valve 200, a condenser 300, a first expansion valve 400, an evaporator 500, and a first branch 600. When the air-conditioning system is turned on in the refrigeration mode under the condition that the external environmental temperature is relatively low or at a normal temperature, the outlet of the compressor 100 discharges high-temperature and high-pressure gaseous refrigerant, the first passage 210 of the four-way valve 200 is connected, and the refrigerant enters the heat release passage of the condenser 300 through the first passage 210 of the four-way valve 200. The refrigerant exchanges heat with the refrigerant in the heat absorption passage of the condenser 300, the refrigerant condenses and cools down, and after flowing out of the condenser 300, it enters the first expansion valve 400. After being depressurized and cooled again by the first expansion valve 400, it enters the heat absorption passage of the evaporator 500. The refrigerant exchanges heat with the air in the heat release passage of the evaporator 500 to cool the air, and thus completes the refrigeration work of the air conditioner for the indoor space. The second passage 220 of the four-way valve 200 is connected, and the refrigerant flows out of the evaporator 500 and returns to the inlet of the compressor 100 through the second passage 220 of the four-way valve 200 and enters the compressor 100. In this refrigeration mode, no refrigerant flows through the first branch 600.

[0028] When the air-conditioning system is turned on the cooling mode under the condition of high external ambient temperature, while ensuring that the compressor, four-way valve 200, condenser 300, first expansion valve 400 and evaporator 500 form a refrigeration circuit for refrigeration operation, the outlet and inlet of the compressor 100 are connected through the first branch 600, which is equivalent to constructing a diversion branch at the outlet of the compressor 100, dividing the refrigerant discharged from the outlet of the compressor 100 into two parts, one part flows to the condenser 300 through the four-way valve 200 and enters the refrigeration circuit, and the other part flows back to the inlet of the compressor 100 through the first branch 600 and enters the compressor 100.

[0029] Thus, the high-temperature refrigerant of the first branch 600 at the inlet of the compressor 100 merges with the low-temperature refrigerant flowing out of the evaporator 500 and out of the first passage 210 of the four-way valve 200, so that the overall temperature of the refrigerant flowing back to the compressor 100 is increased, and then the exhaust temperature at the outlet of the compressor 100 is increased, thereby increasing the condensation temperature of the refrigerant at the condenser 300, increasing the outdoor heat exchange temperature difference, and improving the refrigeration capacity of the air-conditioning system under high-temperature conditions, thereby ensuring the indoor heat exchange refrigeration effect under high-temperature conditions. Compared with the traditional air-conditioning system, the present invention introduces the first branch 600 to increase the exhaust temperature of the compressor 100, replacing the operation of increasing the frequency of the compressor 100 and reducing the opening of the electronic expansion valve when the air-conditioning system increases the exhaust temperature. The frequency of the compressor 100 is increased less, ensuring a higher refrigeration capacity and reliability of the compressor 100, as well as the stability of the air-conditioning system.

[0030] In this embodiment, the first outlet of the four-way valve 200 is connected to the first inlet to form a first passage 210, the second outlet is connected to the second inlet to form a second passage 220, the first outlet of the four-way valve 200 is connected to the inlet of the heat release passage of the condenser 300, the second outlet of the four-way valve 200 is connected to the inlet of the compressor 100, the first inlet of the four-way valve 200 is connected to the outlet of the compressor 100, and the second inlet of the four-way valve 200 is connected to the outlet of the heat absorption passage of the evaporator 500. The outlet of the compressor 100 is connected to the first inlet of the four-way valve 200 through the first pipeline 910, and the second outlet of the four-way valve 200 is connected to the inlet of the compressor 100 through the second pipeline 920. One end of the first branch 600 is connected to the first pipeline 910, and the other end is connected to the second pipeline 920, that is, the refrigerant is diverted on the first pipeline 910 to provide a confluence for the refrigerant in the second pipeline 920. According to an embodiment provided by the present invention, the first branch 600 is provided with a second expansion valve 610.

[0031] In this embodiment, a second expansion valve 610 is provided on the first branch 600. The second expansion valve 610 can reduce the pressure of the high-temperature and high-pressure gaseous refrigerant flowing out of the outlet of the compressor 100 into the first branch 600 to a certain extent. At the same time, by adjusting the opening degree of the second expansion valve 610, the flow rate and pressure of the refrigerant in the first branch 600 can be controlled.

[0032] When the air-conditioning system is in the cooling mode under high-temperature conditions, the second expansion valve 610 is opened, and the opening degree of the second expansion valve 610 is adjusted until the temperature of the refrigerant discharged from the outlet of the compressor 100 meets the requirements. When the air conditioner is in the cooling mode under low-temperature or normal-temperature conditions, the second expansion valve 610 is completely closed, and all the refrigerant discharged from the outlet of the compressor 100 flows into the refrigeration circuit.

[0033] According to an embodiment provided by the present invention, the air-conditioning system further includes a second branch 700. The second branch 700 is connected between the inlet of the second passage 220 of the four-way valve 200 and the inlet of the first expansion valve 400, and the second branch 700 is adapted to exchange heat with the electronic control component 900.

[0034] In this embodiment, the air-conditioning system mainly consists of a compressor 100, a four-way valve 200, a condenser 300, a first expansion valve 400, an evaporator 500, a first branch 600, and a second branch 700. While ensuring that the compressor, the four-way valve 200, the condenser 300, the first expansion valve 400, and the evaporator 500 form a refrigeration circuit for refrigeration work and the first branch 600 under high-temperature conditions increases the exhaust temperature of the compressor 100, the second branch 700 connects the second inlet of the four-way valve 200 to the inlet of the first expansion valve 400, which is equivalent to constructing a diversion branch at the second inlet of the four-way valve 200, dividing the refrigerant discharged from the outlet of the heat absorption passage of the evaporator 500 into two parts. One part flows through the four-way valve 200 and then returns to the compressor 100, and the other part flows through the second branch 700 to the first expansion valve 400.

[0035] When refrigerating under high-temperature conditions, the temperature of the electronic control component 900 on the outdoor side of the air-conditioning system is also relatively high, and the high-temperature refrigeration poses a greater test to the electronic control component 900. When the air-conditioning system refrigerates at high temperature, it is also necessary to ensure that the electronic control component 900 can operate normally for a long time. Therefore, before the refrigerant flows out of the evaporator 500 and returns to the compressor 100, a part of the low-temperature refrigerant is diverted to exchange heat with the electronic control component 900 on the outdoor side of the air-conditioning system to cool the electronic control component 900 and improve the reliability of the electronic control component 900 at high temperature. The air-conditioning system can introduce the second branch 700 to cool the electronic control component 900 while improving the high-temperature refrigeration capacity. The refrigerant in the second branch 700 enters the refrigeration circuit again through the first expansion valve 400 after heat exchange, maintaining the stability of the refrigerant flow rate in the refrigeration circuit.

[0036] When refrigerating, the second branch 700 can return the refrigerant from the indoor unit to the outdoor unit. At this time, the temperature of the refrigerant is less than 40°C, and it exchanges heat with the electronic control component 900 to cool down the electronic control component 900. At this time, the temperature of the electronic control component 900 is 90 - 100°C, and then it returns to the front of the first expansion valve 400 to converge with the refrigerant in the third pipeline 930, and then throttles through the first expansion valve 400.

[0037] The outlet of the heat absorption path of the evaporator 500 is connected to the second inlet of the four-way valve 200 through the third pipeline 930. The outlet of the heat release path of the condenser 300 is connected to the inlet of the first expansion valve 400 through the fourth pipeline 940. One end of the second branch 700 is connected to the third pipeline 930, and the other end is connected to the fourth pipeline 940, that is, the refrigerant is branched on the third pipeline 930 to provide confluence for the refrigerant in the fourth pipeline 940.

[0038] According to an embodiment provided by the present invention, the second branch 700 is provided with a heat exchange component.

[0039] In this embodiment, a heat exchange component is arranged on the second branch 700. The heat exchange component is arranged near the electronic control component 900. When the refrigerant flows into the heat exchange component through the second branch 700, the heat of the electronic control component 900 can exchange heat with the refrigerant, so as to accurately and directly cool down the electronic control component 900.

[0040] The heat exchange component can be a heat exchange tube, which cooperates with a fan and heat dissipation fins, etc. to exchange heat with the electronic control component 900. In addition to setting a heat exchange component on the second branch 700 to control the heat exchange between the refrigerant in the second branch 700 and the electronic control component 900, the second branch 700 can also be directly configured as a pipeline composed of a capillary tube, which can also achieve the refrigeration effect of the electronic control component 900 through heat exchange. Moreover, the capillary tube as the second branch 700 has a small volume and is more suitable for being arranged between the electronic control components 900, and will not greatly affect the refrigerant flow in the refrigeration circuit, avoiding affecting the refrigeration capacity of the indoor unit when adding the second branch 700.

[0041] According to an embodiment provided by the present invention, the second branch 700 is provided with a valve body.

[0042] In this embodiment, a valve body is arranged on the second branch 700. The valve body can control the opening and closing of the second branch 700. When the air conditioning system is in a low-temperature working condition or a normal-temperature working condition, the valve body can be completely closed, and there is no refrigerant flowing in the second branch 700, and there is no need to cool down the electronic control component 900 through the second branch 700. When the air conditioning system is in a high-temperature working condition, the valve body can be opened, and the refrigerant flows in the second branch 700 to refrigerate the electronic control component 900. The opening and closing control instructions of the valve body can also be set according to the actual temperature of the electronic control component 900.

[0043] In addition to arranging a valve body on the second branch 700 to control the refrigerant flow rate, the second branch 700 can also be directly configured as a pipeline component of a capillary tube, so that the flow rate of the second branch 700 is small and will not significantly affect the refrigerant flow rate in the refrigeration circuit, avoiding affecting the refrigeration capacity of the indoor unit when adding the second branch 700.

[0044] The valve body component can control the opening and closing of the second branch 700, and can also adjust the flow rate of the refrigerant in the second branch 700 by adjusting the opening of the valve body, thereby adjusting the heat exchange amount with the electronic control component 900 and controlling the refrigeration temperature of the electronic control component 900.

[0045] According to an embodiment provided by the present invention, the air conditioning system further includes a temperature sensor 800, and the temperature sensor 800 is adapted to detect the condensation temperature of the refrigerant in the condenser 300.

[0046] In this embodiment, the air conditioning system mainly consists of a compressor 100, a four-way valve 200, a condenser 300, a first expansion valve 400, an evaporator 500, a first branch 600, a second branch 700 and a temperature sensor 800. The temperature sensor 800 can be used to detect the condensation temperature of the refrigerant in the condenser 300. By adjusting the opening of the first expansion valve 400 to make the condensation temperature reach the set condensation temperature, that is, the opening of the first expansion valve 400 is regulated by the condensation temperature.

[0047] By changing the opening of the first expansion valve 400, the pressure at the first expansion valve 400 is adjusted, the pressure of the condenser 300 can be controlled, thereby adjusting the heat exchange situation of the refrigerant in the condenser 300, and further affecting the condensation temperature of the refrigerant in the condenser 300, which is beneficial to more accurately increase the outdoor heat exchange temperature difference, improve the refrigeration capacity of the air conditioning system under high temperature conditions, and further improve the indoor heat exchange and refrigeration effect under high temperature conditions.

[0048] According to an embodiment provided by the present invention, a first stop valve 510 is provided on the pipeline connecting the first expansion valve 400 and the evaporator 500; a second stop valve 520 is provided on the pipeline connecting the evaporator 500 and the second passage 220 of the four-way valve 200.

[0049] In this embodiment, the outlet of the first expansion valve 400 is connected to the inlet of the heat absorption passage of the evaporator 500 through a fifth pipeline 950, and a first stop valve 510 is arranged on the fifth pipeline 950. The outlet of the heat absorption passage of the evaporator 500 is connected to the second inlet of the four-way valve 200 through a third pipeline 930, and a second stop valve 520 is arranged on the third pipeline 930. The first stop valve 510 can adjust the refrigerant flow rate in the fifth pipeline 950, and the second stop valve 520 can adjust the refrigerant flow rate in the third pipeline 930.

[0050] In this embodiment, the first shut-off valve 510 may be a two-way shut-off valve, and the second shut-off valve 520 may be a three-way shut-off valve.

[0051] The air-conditioning system provided by the present invention will be described below. The control methods of the air-conditioning system described below can be referred to each other correspondingly.

[0052] An embodiment of the present invention further provides a control method for an air-conditioning system, which is applied to the air-conditioning system as described in the above embodiment, and includes: Obtain the outdoor temperature; Determine that the outdoor temperature is higher than the set outdoor temperature, open the second expansion valve 610, and connect the inlet of the compressor 100 to the liquid inlet through the first branch 600; Adjust the opening degree of the second expansion valve 610 until the exhaust temperature of the compressor 100 reaches the set exhaust temperature.

[0053] The control method of the air-conditioning system according to the embodiment of the present invention first detects the outdoor temperature, determines whether to enter the high-temperature refrigeration mode based on the outdoor temperature, and determines whether the outdoor temperature is higher than the set outdoor temperature. If the outdoor temperature TC is greater than the set outdoor temperature T1, the air-conditioning system enters the high-temperature refrigeration mode. The second expansion valve 610 is opened, and part of the refrigerant directly flows back from the outlet of the compressor 100 to the inlet of the compressor 100 through the first branch 600. According to the pre-adjustment, a suitable set exhaust temperature, set condensation temperature, and external fan speed can be obtained while ensuring the indoor cooling capacity. Then, by adjusting the opening degree of the second expansion valve 610, the exhaust temperature of the compressor 100 reaches the set exhaust temperature, that is, the opening degree of the second expansion valve 610 is regulated by the exhaust temperature. Through the adjustment of the first branch 600 and the second expansion valve 610, the exhaust temperature can be increased without increasing the frequency of the compressor 100 or minimizing the increase in frequency, ensuring the indoor cooling capacity and improving the operation reliability of the compressor under high-temperature conditions.

[0054] In this embodiment, if the outdoor temperature TC is less than or equal to the set outdoor temperature T1, the air-conditioning system does not enter the high-temperature refrigeration mode, the second expansion valve 610 is fully closed, and the compressor 100 operates according to the set exhaust temperature. The value of the set outdoor temperature T1 can be set according to the actual type of the air-conditioning system, the type of the external environment, etc., such as 50°C.

[0055] In the refrigeration mode when the air-conditioning system is under high-temperature conditions, the opening degree of the second expansion valve 610 is controlled by the set exhaust temperature. If the actual exhaust temperature of the compressor 100 is lower than the set exhaust temperature, the opening degree of the second expansion valve 610 is controlled to become larger; if the actual exhaust temperature of the compressor 100 is higher than the set exhaust temperature, the opening degree of the second expansion valve 610 is controlled to become smaller. The second expansion valve 610 is arranged on the first branch 600. The larger the opening degree of the second expansion valve 610, the more refrigerant enters the inlet from the outlet of the compressor 100. The temperature of the refrigerant discharged from the outlet of the compressor 100 is relatively high. The larger the opening degree of the second expansion valve 610, the higher the suction gas temperature of the compressor 100, and the exhaust temperature of the compressor 100 will also increase. Therefore, increasing the opening degree of the second expansion valve 610 will increase the exhaust temperature.

[0056] The method for adjusting the opening degree of the second expansion valve 610 is realized based on the actual exhaust temperature and the set exhaust temperature of the compressor 100, and can be determined according to the change of the actual exhaust temperature of the compressor 100, or can also be determined according to the change of the difference between the actual exhaust temperature and the set exhaust temperature.

[0057] When it is determined according to the change of the difference between the actual exhaust temperature and the set exhaust temperature, the adjustment amount Δ of the opening degree of the second expansion valve 610 θp = Kp ·( T 0 - T p )+ Ki ·∫( T 0 - T p ) dt , where Kp and Ki are the proportional and integral coefficients, T 0 is the set exhaust temperature, T p is the actual exhaust temperature.

[0058] According to an embodiment provided by the present invention, the control method of the air-conditioning system further includes: Adjusting the opening degree of the first expansion valve 400 until the condensation temperature of the refrigerant reaches the set condensation temperature.

[0059] In this embodiment, by adjusting the opening degree of the first expansion valve 400, the condensation temperature of the refrigerant at the condenser 300 reaches the set condensation temperature, that is, the opening degree of the first expansion valve 400 is regulated by the condensation temperature. Thus, the regulation of the first expansion valve 400 and the second expansion valve 610 is coordinated to ensure the dynamic balance of the refrigerant inside the system during high-temperature refrigeration, and to ensure that the air-conditioning system can improve the heat exchange effect and reliability.

[0060] In the refrigeration mode when the air - conditioning system is in a high - temperature operating condition, the opening degree of the first expansion valve 400 is controlled by the set condensation temperature. If the actual condensation temperature of the refrigerant in the condenser 300 is lower than the set condensation temperature, the opening degree of the first expansion valve 400 is controlled to decrease; if the actual condensation temperature of the refrigerant in the condenser 300 is higher than the set condensation temperature, the opening degree of the first expansion valve 400 is controlled to increase. The smaller the opening degree of the first expansion valve 400, the more refrigerant there is on the condenser 300 side, the condensation pressure will increase, and the corresponding condensation temperature will also increase.

[0061] The method of adjusting the opening degree of the first expansion valve 400 is realized based on the actual condensation temperature and the set condensation temperature, and can be determined according to the change of the actual condensation temperature, or can be determined according to the change of the difference between the actual condensation temperature and the set condensation temperature.

[0062] When it is determined according to the change of the difference between the actual condensation temperature and the set condensation temperature, the opening degree adjustment amount Δ of the first expansion valve 400 θq =- Kq ·( T q - T 1 )- Kj ·∫( T q - T 1 ) dt , where, Kq and Kj are the proportional and integral coefficients, T 1 is the set condensation temperature, T q is the actual condensation temperature.

[0063] According to an embodiment provided by the present invention, the refrigerant flow rate of the first branch 600 at the maximum opening degree of the second expansion valve 610 is less than the refrigerant flow rate of the compressor 100 passing through the four - way valve 200.

[0064] Since the first branch 600 is a shunt at the outlet of the compressor 100, in order to ensure the gas supply volume and gas supply pressure of the compressor 100 to the refrigeration circuit, it is set that the refrigerant flow rate of the first branch 600 at the maximum opening degree of the second expansion valve 610 is also much less than the refrigerant flow rate of the compressor 100 entering the four - way valve 200 and then entering the refrigeration circuit.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An air conditioning system, characterized in that, Comprising: The outlet of the compressor (100), the first passage (210) of the four-way valve (200), the condenser (300), the first expansion valve (400), the evaporator (500), the second passage (220) of the four-way valve (200), and the inlet of the compressor (100) are sequentially connected to form a refrigeration circuit; A first branch (600), which is connected between the outlet of the compressor (100) and the inlet of the compressor (100).

2. The air conditioning system according to claim 1, wherein, The first branch (600) is provided with a second expansion valve (610).

3. The air conditioning system according to claim 2, wherein, Further comprising: A second branch (700), which is connected between the inlet of the second passage (220) of the four-way valve (200) and the inlet of the first expansion valve (400), and the second branch (700) is adapted to exchange heat with the electronic control component (900).

4. The air-conditioning system according to claim 3, wherein The second branch (700) is provided with a heat exchange component.

5. The air conditioning system according to claim 3, characterized in that, The second branch (700) is provided with a valve body.

6. The air conditioning system according to claim 1, wherein Further comprising: A temperature sensor (800), which is adapted to detect the condensation temperature of the refrigerant in the condenser (300).

7. The air-conditioning system according to any one of claims 1 to 6, characterized in that, A first stop valve (510) is provided on the pipeline connecting the first expansion valve (400) and the evaporator (500); A second stop valve (520) is provided on the pipeline connecting the evaporator (500) and the second passage (220) of the four-way valve (200).

8. A control method for an air conditioning system, characterized in that, Applied to the air-conditioning system according to any one of claims 2 to 7, comprising: Obtaining the outdoor temperature; Determining that the outdoor temperature is higher than the set outdoor temperature, opening the second expansion valve (610), and connecting the inlet of the compressor (100) to the liquid inlet through the first branch (600); Adjusting the opening degree of the second expansion valve (610) until the exhaust temperature of the compressor (100) reaches the set exhaust temperature.

9. The control method of the air conditioning system according to claim 8, wherein, Further comprising: Adjusting the opening degree of the first expansion valve (400) until the condensation temperature of the refrigerant reaches the set condensation temperature.

10. The control method of the air conditioning system according to claim 8, characterized in that, The refrigerant flow rate of the first branch (600) at the maximum opening degree of the second expansion valve (610) is less than the refrigerant flow rate of the compressor (100) introduced into the four-way valve (200).

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