WO2018006600A1

WO2018006600A1 - Air conditioning system, scroll compressor and method for adjusting back pressure thereof

Info

Publication number: WO2018006600A1
Application number: PCT/CN2017/073480
Authority: WO
Inventors: 李冬元; 黄柏英
Original assignee: 广东美的暖通设备有限公司; 美的集团股份有限公司
Priority date: 2016-07-08
Filing date: 2017-02-14
Publication date: 2018-01-11

Abstract

Disclosed is an air conditioning system (100), comprising an evaporator (1), a condenser (2), a first electronic expansion valve (3), a second electronic expansion valve (4), a third electronic expansion valve (5) and a scroll compressor (10). One end of the evaporator (1) is in communication with an air-suction opening (7) of the compressor (10), and the other end thereof is connected to the first electronic expansion valve (3) and the third electronic expansion valve (5) respectively. One end of the condenser (2) is in communication with an air exhaust opening (8) of the scroll compressor (10), and the other end thereof is connected to the first electronic expansion valve (3) and the second electronic expansion valve (4) respectively. A medium pressure air guide opening (9) of the scroll compressor (10) connects the second electronic expansion valve (4) and the third electronic expansion valve (5). The air conditioning system (100) further comprises three pressure sensors (11) respectively and correspondingly disposed at the air-suction opening (7), the air exhaust opening (8) and the medium pressure air guide opening (9) of the scroll compressor (10), and further comprises a controller (12) for controlling the opening degree of the first electronic expansion valve (3), the second electronic expansion valve (4) and the third electronic expansion valve (5) according to signal values monitored by the three pressure sensors (11).

Description

Air conditioning system, scroll compressor and back pressure adjustment method thereof

Technical field

The invention relates to the technical field of refrigeration, and in particular to an air conditioning system, a scroll compressor and a back pressure adjusting method thereof.

Background technique

Scroll compressors are widely used in ordinary refrigeration and air conditioning systems due to their simple structure, small size, light weight and high efficiency. Among them, the tightness between the dynamic and static scrolls plays a crucial role in the performance of the compressor, and the main influencing factor of the sealing is the sealing back pressure between the moving and stationary scrolls, and whether the back pressure design is Reasonably directly affect the performance of the compressor under different working conditions. If the back pressure design is too large, there will be a large fit between the moving and stationary scrolls. Although the sealing is ensured, the translation between the movable scroll and the fixed scroll will produce a larger Frictional power consumption, which reduces the efficiency of the compressor. If the back pressure design is too small, the sealing force between the moving and stationary scrolls is insufficient, resulting in leakage of the compression chamber between the moving and stationary scrolls, resulting in a decrease in refrigerant flow rate and an increase in power consumption, thereby reducing the compressor. s efficiency.

The axial gas separation force of the compression chamber between the stationary and the fixed scrolls can be in the form of floating of the movable scroll, that is, the medium pressure gas in the compression chamber is opened by opening a back pressure hole on the movable scroll The back of the orbiting scroll is combined with high-pressure gas to generate back pressure, which is mostly used in high-pressure chamber scroll compressors. The movable scroll floating seal form also has a back pressure form composed of suction pressure and exhaust pressure.

For the floating seal type of the movable scroll, in the prior art, the back pressure type of the combination of the medium pressure and the high pressure is adopted, and the position of the back pressure hole on the movable scroll is fixedly opened, so the connection pressure ratio of the medium pressure is fixed. changing. Therefore, the suitable back pressure can only be designed for a certain working pressure ratio range. In this way, there will be some high load and high pressure ratio working conditions, and the sealing back pressure is too large to generate large frictional power consumption, and some low pressure. Compared with low load conditions, the seal back pressure is too small to cause leakage of the compressor refrigerant.

Summary of the invention

The main object of the present invention is to provide an air conditioning system, a scroll compressor and a back pressure adjusting method thereof, which are intended to realize automatic adjustment of back pressure when the compressor is operated under different working conditions, thereby solving the power increase caused by frictional power consumption or Leakage causes problems with reduced cooling capacity.

To achieve the above object, the present invention provides an air conditioning system including an evaporator, a condenser, a first electronic expansion valve, a second electronic expansion valve, a third electronic expansion valve, and an intake port and an exhaust port. And a scroll compressor of a medium pressure air port, wherein one end of the evaporator is in communication with the air intake port, and the other end is connected to the first electronic expansion valve and the third electronic expansion valve, respectively, the condenser One end is in communication with the exhaust port, and the other end is respectively associated with the a first electronic expansion valve and a second electronic expansion valve are connected, the medium pressure air guiding port is connected to the second electronic expansion valve and the third electronic expansion valve; the air conditioning system further includes a correspondingly disposed at the air inlet, Three pressure sensors at the exhaust port and the medium pressure air port, and controlling the opening of the first electronic expansion valve, the second electronic expansion valve, and the third electronic expansion valve according to signal values monitored by the three pressure sensors Controller.

In some embodiments, the air conditioning system further includes a surge tank having one end in communication with the medium pressure air outlet and the other end connected to the second electronic expansion valve and the third electronic expansion valve, respectively.

In some embodiments, the controller is configured to obtain an inspiratory pressure value at the inhalation port, an exhaust pressure value at the exhaust port, and a pilot gas pressure value at the intermediate pressure air port, according to Calculating a target medium pressure value according to the intake pressure value and the exhaust pressure value, and controlling the first electronic expansion valve to operate normally according to the target medium pressure value, and adjusting the second electronic expansion valve and/or Or the opening degree of the third electronic expansion valve until the value of the air guiding pressure at the medium pressure air guiding port reaches the target medium pressure value.

In some embodiments, the controller is further configured to control the first electronic expansion valve to operate normally according to the target medium pressure value, and adjust an opening degree of the second electronic expansion valve and/or the third electronic expansion valve, And obtaining, in real time, the air pressure value fed back by the pressure sensor at the medium pressure air guiding port, and controlling the third electronic expansion valve to be closed when the difference between the target medium pressure value and the air guiding pressure value is large And increasing an opening degree of the second electronic expansion valve; controlling the second electronic expansion valve to close or reduce the first when the difference between the target intermediate pressure value and the air guiding pressure value is small The opening of the two electronic expansion valve reduces the opening of the third electronic expansion valve.

In some embodiments, the controller is further configured to calculate a pressure ratio between the exhaust pressure value and the intake pressure value, and when the pressure ratio meets a predetermined range, acquire a pressure ratio corresponding to the pressure ratio The target medium pressure value is adjusted according to the target medium pressure value until the air pressure value at the medium pressure air outlet reaches the target medium pressure value.

In some embodiments, the controller is further configured to: when the exhaust pressure value and the inspiratory pressure value meet a predetermined range, acquire a corresponding target medium pressure value, and adjust according to the target medium pressure value The opening degree of the second electronic expansion valve until the value of the air guiding pressure at the intermediate pressure air guiding port reaches the target intermediate pressure value.

To achieve the above object, the present invention also provides a back pressure adjustment method for an air conditioning system, the back pressure adjustment method of the air conditioning system comprising the following steps:

The three pressure sensors of the air conditioning system respectively monitor the pressure values at the suction port, the exhaust port and the medium pressure air port of the scroll compressor, and send the monitored pressure values to the controller;

The controller correspondingly controls the opening degrees of the first electronic expansion valve, the second electronic expansion valve, and/or the third electronic expansion valve according to the pressure value to adjust the magnitude of the centering pressure.

In some embodiments, the controller controls the opening of the first electronic expansion valve, the second electronic expansion valve, and/or the third electronic expansion valve according to the pressure value to adjust the magnitude of the medium pressure. Includes:

The controller acquires an inspiratory pressure value at the intake port, a exhaust pressure value at the exhaust port, and a pilot gas pressure value at the intermediate pressure air port;

Calculating a target medium pressure value according to the inspiratory pressure value and the exhaust pressure value;

Controlling the first electronic expansion valve to operate normally according to the target medium pressure value, and adjusting the opening degree of the second electronic expansion valve and/or the third electronic expansion valve until the air pressure at the medium pressure air guiding port The value reaches the target medium pressure value.

In some embodiments, the first electronic expansion valve is controlled to operate normally according to the target medium pressure value, and the opening degree of the second electronic expansion valve and/or the third electronic expansion valve is adjusted until the middle The steps of the gas pressure value at the pressure guiding port reaching the target medium pressure value include:

Controlling the first electronic expansion valve to operate normally according to the target medium pressure value, adjusting the opening degree of the second electronic expansion valve and/or the third electronic expansion valve, and acquiring the pressure sensor at the medium pressure air guiding port in real time. Feedback air pressure value;

When the difference between the target medium pressure value and the air guiding pressure value is large, controlling the third electronic expansion valve to close, and increasing the opening degree of the second electronic expansion valve;

Controlling the second electronic expansion valve to close or reduce the opening degree of the second electronic expansion valve when the difference between the target intermediate pressure value and the pilot gas pressure value is small, and reducing the third The opening of the electronic expansion valve.

In some embodiments, the controller acquires an inspiratory pressure value at the intake port, a exhaust pressure value at the exhaust port, and a step of a pilot gas pressure value at the intermediate pressure air port. Also includes:

Calculating a pressure ratio between the exhaust pressure value and the inspiratory pressure value;

When the pressure ratio value satisfies a predetermined range, acquiring a target medium pressure value corresponding to the pressure ratio value;

Adjusting the opening degree of the second electronic expansion valve according to the target medium pressure value until the air guiding pressure value at the medium pressure air guiding port reaches the target intermediate pressure value.

When the exhaust pressure value and the inspiratory pressure value satisfy a predetermined range, acquiring a corresponding target medium pressure value;

In order to achieve the above object, the present invention also provides a scroll compressor including a housing and an intake port, an exhaust port, and a medium-pressure air port provided on the housing, the suction The gas port is in communication with one end of an evaporator of the air conditioning system, the exhaust port being in communication with one end of a condenser of the air conditioning system, the medium pressure air port for communicating the evaporator and the other end of the condenser.

The air conditioning system, the scroll compressor and the back pressure regulating method thereof are provided by the evaporator, the one end and the row connected to the first electronic expansion valve and the third electronic expansion valve respectively. a condenser having a gas port connected to the other end and respectively connected to the first electronic expansion valve and the second electronic expansion valve, respectively corresponding to the suction port, Three pressure sensors at the exhaust port and the medium pressure air port, and controlling the opening of the first electronic expansion valve, the second electronic expansion valve, and the third electronic expansion valve according to signal values monitored by the three pressure sensors Controller. In this way, the invention can realize the automatic adjustment of the back pressure when the compressor is operated under different working conditions, thereby solving the problem that the power increase or leakage caused by the friction power consumption causes the cooling capacity to decrease.

DRAWINGS

1 is a schematic view of a circulation system of an embodiment of an air conditioning system of the present invention;

Figure 2 is a cross-sectional view of the scroll compressor of the present invention;

3 is a schematic flow chart of a first embodiment of a method for adjusting back pressure of an air conditioning system according to the present invention;

4 is a first step of the step controller of FIG. 3 for controlling the opening degree of the first electronic expansion valve, the second electronic expansion valve, and/or the third electronic expansion valve according to the pressure value, and adjusting the magnitude of the centering pressure. Schematic diagram of the refinement process of the embodiment;

5 is a step of FIG. 4, according to the target medium pressure value, controlling the first electronic expansion valve to operate normally, and adjusting the opening degree of the second electronic expansion valve and/or the third electronic expansion valve until the medium pressure A schematic diagram of the refinement flow of the gas pressure value at the gas outlet to the target medium pressure value;

6 is a second step of adjusting the opening degree of the first electronic expansion valve, the second electronic expansion valve, and/or the third electronic expansion valve according to the pressure value in the step controller of FIG. 3 to adjust the magnitude of the centering pressure; Schematic diagram of the refinement process of the embodiment;

Figure 7 is a schematic view showing the scroll compressors of the air conditioning system of the present invention according to different ranges of discharge and suction pressure ratios;

8 is a third step of the step controller in FIG. 3 corresponding to controlling the opening degree of the first electronic expansion valve, the second electronic expansion valve, and/or the third electronic expansion valve according to the pressure value, and adjusting the magnitude of the centering pressure Schematic diagram of the refinement process of the embodiment;

Fig. 9 is a schematic view showing the different operating conditions of the scroll compressor of the air conditioning system according to the present invention according to the fixed condensing pressure and the evaporation pressure.

The implementation, functional features, and advantages of the present invention will be further described in conjunction with the embodiments.

detailed description

It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides an air conditioning system, a scroll compressor and a back pressure adjusting method thereof, which respectively detect pressure values of an intake port, an exhaust port and a medium pressure air guide port by using three pressure sensors, and then control by a controller First electron The opening degree of the expansion valve, the second electronic expansion valve, and the third electronic expansion valve, thereby adjusting the intermediate pressure value at the intermediate pressure air port. Therefore, the present invention can realize the automatic adjustment of the back pressure when the compressor is operated under different working conditions, thereby solving the problem that the power increase or leakage caused by the frictional power consumption causes the cooling capacity to decrease.

Referring to FIG. 1, in an embodiment, the air conditioning system 100 includes an evaporator 1, a condenser 2, a first electronic expansion valve 3, a second electronic expansion valve 4, a third electronic expansion valve 5, a surge tank 6, and A scroll compressor 10 having an intake port 7, an exhaust port 8, and a medium-pressure air port 9. One end of the evaporator 1 is connected to the air inlet 7 and the other end is connected to the first electronic expansion valve 3 and the third electronic expansion valve 5, and one end of the condenser 2 and the row The gas port 8 is connected, and the other end is connected to the first electronic expansion valve 3 and the second electronic expansion valve 4 respectively; one end of the surge tank 6 is connected to the medium pressure air port 9 and the other end is respectively associated with the The second electronic expansion valve 4 and the third electronic expansion valve 5 are connected. The surge tank 6 has an inlet and two outlets: an inlet communicates with the second electronic expansion valve 4, an outlet communicates with the medium pressure air outlet 9, and another outlet communicates with the third electronic expansion valve 5, such that When a relatively large medium pressure is required, the third electronic expansion valve 5 is closed to adjust the opening degree of the second electronic expansion valve 4; when a small intermediate pressure is required, the second electronic expansion valve 4 is closed or reduced, The opening degree of the third electronic expansion valve 5 is adjusted.

The air conditioning system 100 further includes three pressure sensors 11 respectively corresponding to the suction port 7, the exhaust port 8, and the intermediate pressure air port 9 (wherein the pressure sensor at the air inlet port 7 is labeled 111, The pressure sensor at the exhaust port 8 is labeled 112, the pressure sensor at the medium pressure air port 9 is labeled 113), and the first electronic expansion valve 3 is controlled according to the signal values monitored by the three pressure sensors 11 The controller 12 of the second electronic expansion valve 4 and the third electronic expansion valve 5 opening degree.

The present invention provides an evaporator 1 which is connected to the first electronic expansion valve 3 and the third electronic expansion valve 5 at one end and is connected to the first electronic expansion valve 3 and the third electronic expansion valve 5, and has one end connected to the exhaust port 8 and the other end respectively connected to the first electron. The expansion valve 3 and the condenser 2 connected to the second electronic expansion valve 4 respectively correspond to the three pressure sensors 11 provided at the suction port 7, the exhaust port 8 and the intermediate pressure air port 9, and according to the three The signal value monitored by the pressure sensor 11 controls the controller 12 of the first electronic expansion valve 3, the second electronic expansion valve 4, and the third electronic expansion valve 5. In this way, the invention can realize the automatic adjustment of the back pressure when the compressor is operated under different working conditions, thereby solving the problem that the power increase or leakage caused by the friction power consumption causes the cooling capacity to decrease.

Further, referring to FIG. 2, the scroll compressor 10 further includes a casing 13 provided with the intake port 7, the exhaust port 8 and the intermediate pressure air port 9, which is disposed in the casing 13 A bracket 14, a compression assembly 15 supported on the upper bracket 14 and a drive assembly 16 that drives the compression assembly 15 to operate.

Specifically, the compression assembly 15 includes a fixed scroll 151 and an orbiting scroll 152 that is eccentrically disposed with respect to the fixed scroll 151 with a phase difference of 180 degrees. The outside of the turbine tooth profile of the orbiting scroll 152 and the inside of the turbine tooth profile of the fixed scroll 151, the inside of the turbine tooth profile of the orbiting scroll 152 and the inside of the fixed scroll 151 A compression chamber 153 is formed outside the turbine tooth profile, and the compression chamber 153 is in communication with the suction port 7.

In this embodiment, the profile of the fixed scroll 151 and the orbiting scroll 152 is an asymmetrical type in which the profile of the fixed scroll 151 is larger than 180° of the profile of the orbiting scroll 152. Line agency. In other embodiments, the line of the fixed scroll 151 may be equal to the symmetrical line mechanism of the profile of the orbiting scroll 152, and the orbiting scroll 152 may be clockwise or counterclockwise. The panning motion of the fixed scroll 151 is performed.

Further, the upper bracket 14 has a support surface 141 for supporting the orbiting scroll 152, and the support surface 141 is recessed into the bottom of the casing 13 at a position corresponding to the outer end of the orbiting scroll 152. The pressure chamber 142 communicates with the medium pressure air port 9 to form a medium pressure Pm.

Further, the drive assembly 16 includes an eccentric crankshaft 161 disposed in the housing 13 along the length of the housing 13 and a motor 162 that drives the rotation of the eccentric crankshaft 161. The orbiting scroll 152 is sleeved. The eccentric crankshaft 161 is driven to rotate the movable scroll 152 in synchronization.

The movable scroll 152 has a sleeve 154 extending toward the bottom of the casing 13 and sleeved on the top end of the eccentric crankshaft 161. The support surface 141 is correspondingly recessed toward the bottom of the casing 13 The casing 154 and the high pressure chamber 143 at the top end of the eccentric crankshaft 161.

Further, the bottom of the casing 13 is provided with an oil chamber 17, an oil guiding assembly 18 whose one end extends into the oil chamber 17 and is connected to the eccentric crankshaft 161, and a lower bracket 19 that fixes the oil guiding assembly 18. An oil guiding groove 20 communicating with the high pressure chamber 143 and the oil guiding assembly 18 is disposed in the eccentric crankshaft 161, and the oil guiding assembly 18 is configured to introduce the freezing oil in the oil chamber 17 into the high pressure chamber 143. , produces high pressure Pd.

Further, a sealing ring 21 and a wave spring (not shown) are further disposed between the movable scroll 152 and the supporting surface 141 of the upper bracket 14 , and the lower portion of the sealing ring 21 passes the waveform The support of the spring acts in close contact with the orbiting scroll 152 to isolate the high pressure chamber 143 and the intermediate pressure chamber 142.

Among them, (Pd × corresponding area) + (Pm × corresponding area) constitutes the back pressure supporting the back of the movable scroll 152, and is mainly used to balance the gas separation force generated during the compression process of the compression chamber 153.

The sealing ring 21 serves to block the high pressure oil (oil and gas mixture) in the high pressure chamber 143 from the medium pressure gas in the intermediate pressure chamber 142 to prevent the high pressure from communicating with the medium pressure gas.

Further, the intermediate pressure chamber 142 is provided with a cross slip ring 23 between the support surface 141 and the movable scroll 152, which can prevent the rotation of the movable scroll 152. In this embodiment, the cross The slip ring 23 can be a European ring.

It should be understood that, when the scroll compressor 10 is in operation, the refrigerant is sucked into the fixed scroll 151 by the suction port 7, and is compressed in the compression chamber 153 formed by the fixed scroll 151 and the movable scroll 152, and compressed. It is discharged from the fixed scroll exhaust port 24 into the sealed space formed by the casing 13, and finally discharged from the exhaust port 8 of the casing 13, completing the process of suction-compression-exhaust. Since the oil chamber 17 communicates with the housing 13, the pressure of the gas discharged from the fixed scroll exhaust port 24 pushes the frozen oil into the high pressure chamber 143 along the oil guiding groove 20, and thus, the high pressure chamber The gas oil pressure in 143 coincides with the pressure at the exhaust port 8. Thus, the back pressure is caused by the high pressure gas in the high pressure chamber 143 and from the surge tank 6 In the case where the pressure guiding port 9 is formed by the medium pressure gas entering the compressor, the present invention only needs to adjust the amount of gas flowing from the surge tank 6 into the intermediate pressure air port 9, and the corresponding medium pressure can be adjusted. Thereby, the adjustment of the back pressure of the scroll compressor 10 is achieved.

As shown in Figure 1, the specific circulation of the refrigerant flows as follows:

The scroll compressor 10 compresses the gaseous low-temperature low-pressure refrigerant sucked into the suction port 7 to the gaseous high-temperature high-pressure refrigerant, and delivers the gaseous high-temperature high-pressure refrigerant to the condenser 2 through the exhaust port 8, and the gaseous high-temperature high-pressure refrigeration After the heat exchange of the condenser 2, the phase changes into a high-pressure liquid refrigerant, and the liquid refrigerant after passing through the condenser 2 is throttled and depressurized through the first electronic expansion valve 3, and then enters the evaporator 1 for heat exchange, and heat exchange is performed. The gaseous low temperature low pressure superheated refrigerant enters the compressor cycle through the suction port 7. The liquid refrigerant passing through the condenser 2 is throttled down to the surge tank 6 through the second electronic expansion valve 4, and enters the compressor cycle through the medium pressure air port 9.

The present invention also provides a back pressure adjustment method for the air conditioning system 100. Referring to FIG. 3, in an embodiment, the back pressure adjustment method of the air conditioning system 100 includes the following steps:

In step S10, the three pressure sensors 11 of the air conditioning system 100 respectively monitor the pressure values at the intake port 7, the exhaust port 8 and the intermediate pressure air port 9 of the scroll compressor 10, and send the monitored pressure values to Controller 12;

In this embodiment, the air conditioning system 100 is respectively provided with a corresponding pressure sensor at the intake port 7, the exhaust port 8 and the intermediate pressure air port 9 of the scroll compressor 10 to transmit the detected pressure value signal. To the controller 12, the controller 12 can adjust the opening degrees of the first electronic expansion valve 3, the second electronic expansion valve 4, and/or the third electronic expansion valve 5 according to the pressure value signal.

In step S20, the controller 12 controls the opening degrees of the first electronic expansion valve 3, the second electronic expansion valve 4, and/or the third electronic expansion valve 5 according to the pressure value to adjust the magnitude of the centering pressure.

In this embodiment, since the surge tank 6 has an inlet and two outlets: an inlet communicates with the second electronic expansion valve 4, an outlet communicates with the intermediate pressure air outlet 9, and another outlet communicates with the third electronic expansion valve 5. In this way, when a large medium pressure is required, the third electronic expansion valve 5 is closed, and the opening degree of the second electronic expansion valve 4 is adjusted; when a small medium pressure is required, the second electron is turned off or reduced. The expansion valve 4 adjusts the opening degree of the third electronic expansion valve 5. In this embodiment, the first electronic expansion valve 3 operates normally. Of course, the opening degree of the first electronic expansion valve 3 can be adjusted according to actual needs.

It should be understood that since the back pressure is composed of the high pressure gas pressure in the high pressure chamber 143 and the medium pressure gas pressure from the surge tank 6 through the medium pressure air port 9 into the compressor. Therefore, the present invention can adjust the corresponding medium pressure by simply adjusting the amount of gas flowing from the surge tank 6 into the intermediate pressure air port 9, thereby achieving adjustment of the back pressure of the scroll compressor 10.

The back pressure regulating method of the air conditioning system 100 provided by the present invention passes through three pressure sensors of the air conditioning system 100 11 respectively monitoring the pressure values at the suction port 7, the exhaust port 8 and the intermediate pressure air port 9 of the scroll compressor 10, and transmitting the monitored pressure values to the controller 12, and then according to the controller 12 The pressure value corresponds to controlling the opening degrees of the first electronic expansion valve 3, the second electronic expansion valve 4, and/or the third electronic expansion valve 5 to adjust the magnitude of the centering pressure. In this way, the invention can realize the automatic adjustment of the back pressure when the compressor is operated under different working conditions, so as to achieve the optimal sealing gas force, thereby solving the problem that the power increase or the leakage caused by the friction power consumption causes the cooling capacity to decrease.

In the first embodiment, as shown in FIG. 4, on the basis of the above-mentioned FIG. 3, the step S20 includes:

Step S201, the controller 12 acquires an inspiratory pressure value at the inhalation port 7, an exhaust pressure value at the exhaust port 8, and a pilot gas pressure value at the intermediate pressure air port 9;

In this embodiment, the controller 12 can receive the gas pressure values sent by the three sensors in real time or at a time, and the controller 12 can also retrieve the gas pressure values in real time or periodically. It should be understood that each pressure sensor may be disposed at a suitable position on the pipeline of the air conditioning system 100, and the comparison of the present invention is not specifically limited.

Step S202, calculating a target medium pressure value according to the inhalation pressure value and the exhaust pressure value;

In this embodiment, the corresponding target back pressure value can be calculated due to the inspiratory pressure value and the exhaust pressure value. Since the gas pressure value in the high pressure chamber 143 is fixed, the target medium pressure value can be calculated. .

Step S203, controlling the first electronic expansion valve 3 to operate normally according to the target medium pressure value, and adjusting the opening degree of the second electronic expansion valve 4 and/or the third electronic expansion valve 5 until the medium pressure guide The air pressure value at the port 9 reaches the target medium pressure value.

In this embodiment, the first electronic expansion valve 3 is always in a normal working state. Of course, the opening degree of the first electronic expansion valve 3 can be adjusted according to actual needs. The opening degrees of the second electronic expansion valve 4 and the third electronic expansion valve 5 are mainly adjusted until the air pressure value at the medium pressure air port 9 reaches the target medium pressure value.

In an embodiment, as shown in FIG. 5, on the basis of the foregoing FIG. 4, the step S203 includes:

Step S2031, controlling the first electronic expansion valve 3 to operate normally according to the target medium pressure value, adjusting the opening degree of the second electronic expansion valve 4 and/or the third electronic expansion valve 5, and acquiring the medium pressure in real time. The air pressure value fed back by the pressure sensor 113 at the air guiding port 9;

In this embodiment, the optimal back pressure is designed mainly for different suction and exhaust pressure changes. The controller 12 can write a program for control. When the controller 12 receives the refrigerant suction pressure Ps and the exhaust pressure Pd signal fed back by the pressure sensor 11, the controller 12 calculates that the compressor satisfies the optimal compression efficiency. The pressure (medium pressure value Pm) controls the first electronic expansion valve 3 and the second electronic expansion valve 4 to operate. After adjusting the opening degree of the second electronic expansion valve 4, a part of the refrigerant is throttled down to the intermediate pressure Pm, and enters the surge tank 6 through the pipeline, wherein the refrigerant gas having a pressure of Pm passes through the pipeline and the medium pressure The air guide port 9 is introduced into the intermediate pressure chamber 142 of the compressor. Medium pressure air inlet 9 front end installation The pressure sensor 11 feeds back a pressure signal to the controller 12 to further adjust the opening degree of the second electronic expansion valve 4 to control the magnitude of the intermediate pressure Pm.

Step S2032, when the difference between the target intermediate pressure value and the air guiding pressure value is large, controlling the third electronic expansion valve 5 to close, and increasing the opening degree of the second electronic expansion valve 4;

Step S2033, when the difference between the target intermediate pressure value and the pilot gas pressure value is small, controlling the second electronic expansion valve 4 to close or reduce the opening degree of the second electronic expansion valve 4, and reduce The opening degree of the third electronic expansion valve 5 is small.

In this embodiment, when the operating condition changes to require a larger medium pressure Pm, that is, when the difference between the target intermediate pressure value and the pilot air pressure value is large, the controller 12 adjusts the opening of the second electronic expansion valve 4. At this time, the third electronic expansion valve 5 is in a closed state. When the operating condition changes requires a small intermediate pressure Pm, the controller 12 controls the third electronic expansion valve 5 to open and adjust the opening degree. At this time, the second electronic expansion valve 4 is in the closed state or reduces the opening degree thereof. The judgment can be made based on the intermediate pressure Pm. I will not repeat them here.

In the second embodiment, as shown in FIG. 6, on the basis of the foregoing FIG. 4, after the step S201, the method further includes:

Step S204, calculating a pressure ratio between the exhaust pressure value and the inspiratory pressure value;

Step S205, when the pressure ratio value satisfies a predetermined range, acquiring a target medium pressure value corresponding to the pressure ratio value;

Step S206, adjusting the opening degree of the second electronic expansion valve 4 according to the target medium pressure value until the air guiding pressure value at the medium pressure air guiding port 9 reaches the target intermediate pressure value.

Referring to FIG. 7, the present embodiment reduces the control difficulty with respect to the first embodiment, and specifically designs the medium voltage control logic according to the compressor in the operating range of the working condition corresponding to different pressure ratio ranges. The compressor operating range is divided into A, B, C, and D regions, including the range of pressure ratios Pd/Ps-1 to Pd/Ps-5. When the working condition is in the A zone, that is, when the pressure ratio is in the range of Pd/Ps-4 to Pd/Ps-5, the target intermediate pressure value Pm can be designed according to Pm=M×Ps (suction pressure), where M It is a value of 1 < M < 2, but it is necessary to ensure M × Ps < Pd (exhaust pressure). Thus, when the compressor operating conditions are in the range of Pd/Ps-4 to Pd/Ps-5, the controller 12 adjusts the opening degree of the second electronic expansion valve 4 according to the information fed back by the respective pressure sensors to ensure Pm= M × Ps. Similarly, when the compressor is operated in the range of B, C, and D respectively, the intermediate pressure Pm can be designed according to Pm=N×Ps, Pm=P×Ps, Pm=Q×Ps, where 1<N<2. 1<P<2, 1<Q<2, but make sure N, P, Q × Ps < Pd. The solution is not limited to the above four areas A, B, C, and D, and more or less areas may be divided according to different situations.

In the third embodiment, as shown in FIG. 8, on the basis of the foregoing FIG. 4, after the step S201, the method further includes:

Step S207, when the exhaust pressure value and the inspiratory pressure value satisfy a predetermined range, acquiring a corresponding target medium pressure value;

Step S208, adjusting the opening degree of the second electronic expansion valve 4 according to the target medium pressure value until the medium pressure air guiding gas The value of the pilot gas pressure at port 9 reaches the target medium pressure value.

Referring to FIG. 9, according to the range of operation of evaporation pressure (suction pressure) and condensing pressure (exhaust pressure), the operating range is divided into four types: A1, B1, C1, and D1 according to a fixed condensing pressure CP and an evaporation pressure EP. region. Among them, CP and EP are set to CP=α(Cmax+Cmin)/2, EP=β(Cmax+Cmin)/2, where 0.5<α<1.5, 0.5<β<1.5. When the working condition is in the range of A1, the target medium pressure value can be designed according to a certain pressure ratio of Ps<Pm<Pd in the range. Thus, when the operating condition is in the range of A1, the controller 12 adjusts the opening degree of the second electronic expansion valve 4 according to the feedback information of the pressure sensor to ensure that Pm is a value of Ps<Pm<Pd, and the solution can be further reduced. The implementation difficulty of the controller 12. Similarly, when the compressor is operated in the range of B1, C1, and D1, the target medium pressure value can be designed according to a certain pressure ratio of Ps<Pm<Pd in the range. The solution is not limited to the above four areas A1, B1, C1, and D1, and more or less areas may be divided according to different situations. It should be understood that, wherein the condensing pressure corresponds to the pressure of the exhaust port 8, and the evaporating pressure corresponds to the pressure of the suction port 7.

The above is only an alternative embodiment of the present invention, and thus does not limit the scope of the invention, and the equivalent structure or equivalent process transformation made by using the specification and the drawings of the present invention, or directly or indirectly applied to other related technologies. The fields are all included in the scope of patent protection of the present invention.

Claims

An air conditioning system, comprising: an evaporator, a condenser, a first electronic expansion valve, a second electronic expansion valve, a third electronic expansion valve, and having an intake port, an exhaust port, and a medium pressure guide a scroll compressor of a gas port, wherein one end of the evaporator is connected to the suction port, and the other end is connected to the first electronic expansion valve and the third electronic expansion valve, respectively, and one end of the condenser is The exhaust port is connected, the other end is respectively connected to the first electronic expansion valve and the second electronic expansion valve, and the medium pressure air guiding port is connected to the second electronic expansion valve and the third electronic expansion valve; The method further includes three pressure sensors respectively corresponding to the air inlet, the air outlet and the medium pressure air outlet, and the first electronic expansion valve and the second according to the signal values monitored by the three pressure sensors. Controller for electronic expansion valve and third electronic expansion valve opening.
The air conditioning system according to claim 1, wherein said air conditioning system further comprises: one end connected to said medium pressure air port and the other end connected to said second electronic expansion valve and said third electronic expansion valve respectively Pressure cans.
The air conditioning system according to claim 1, wherein said controller is configured to acquire an intake pressure value at said intake port, a discharge pressure value at said exhaust port, and said medium pressure air port The air pressure value at the position, the target medium pressure value is calculated according to the suction pressure value and the exhaust pressure value, and the first electronic expansion valve is controlled to operate normally according to the target medium pressure value, The opening of the second electronic expansion valve and/or the third electronic expansion valve is adjusted until the value of the pilot gas pressure at the intermediate pressure air outlet reaches the target intermediate pressure value.
The air conditioning system according to claim 3, wherein said controller is further configured to control said first electronic expansion valve to operate normally according to said target intermediate pressure value, adjust said second electronic expansion valve and/or The opening degree of the three-electron expansion valve, and real-time acquisition of the air-conducting pressure value fed back by the pressure sensor at the medium-pressure air guiding port, when the difference between the target medium-pressure value and the air-conducting pressure value is large, control The third electronic expansion valve is closed, and increases an opening degree of the second electronic expansion valve; and when the difference between the target intermediate pressure value and the air guiding pressure value is small, controlling the second electronic expansion The valve closes or reduces the opening of the second electronic expansion valve and reduces the opening of the third electronic expansion valve.
The air conditioning system according to claim 3 or 4, wherein said controller is further configured to calculate a pressure ratio between said exhaust pressure value and said intake pressure value, wherein said pressure ratio satisfies a predetermined value a range, a target medium pressure value corresponding to the pressure ratio value is obtained, and an opening degree of the second electronic expansion valve is adjusted according to the target medium pressure value until the air pressure value at the medium pressure air outlet reaches the target Pressure value.
The air conditioning system according to claim 3 or 4, wherein the controller is further configured to acquire a corresponding target medium pressure value when the exhaust pressure value and the suction pressure value satisfy a predetermined range, And adjusting the opening degree of the second electronic expansion valve according to the target medium pressure value until the air guiding pressure value at the medium pressure air guiding port reaches the target medium pressure value.
A back pressure regulating method for an air conditioning system, characterized in that the back pressure adjusting method of the air conditioning system comprises the following steps:

The three pressure sensors of the air conditioning system respectively monitor the pressure values at the suction port, the exhaust port and the medium pressure air port of the scroll compressor, and send the monitored pressure values to the controller;

The controller correspondingly controls the opening degrees of the first electronic expansion valve, the second electronic expansion valve, and/or the third electronic expansion valve according to the pressure value to adjust the magnitude of the centering pressure.
The back pressure adjusting method of an air conditioning system according to claim 7, wherein the controller correspondingly controls the first electronic expansion valve, the second electronic expansion valve, and/or the third electronic expansion valve according to the pressure value The opening, the steps of adjusting the size of the centering pressure include:

The controller acquires an inspiratory pressure value at the intake port, a exhaust pressure value at the exhaust port, and a pilot gas pressure value at the intermediate pressure air port;

Calculating a target medium pressure value according to the inspiratory pressure value and the exhaust pressure value;

Controlling the first electronic expansion valve to operate normally according to the target medium pressure value, and adjusting the opening degree of the second electronic expansion valve and/or the third electronic expansion valve until the air pressure at the medium pressure air guiding port The value reaches the target medium pressure value.
The back pressure adjusting method of an air conditioning system according to claim 8, wherein said controlling said first electronic expansion valve to operate normally according to said target intermediate pressure value while adjusting said second electronic expansion valve and/or The opening of the third electronic expansion valve until the air pressure value at the medium pressure air outlet reaches the target medium pressure value includes:

Controlling the first electronic expansion valve to operate normally according to the target medium pressure value, adjusting the opening degree of the second electronic expansion valve and/or the third electronic expansion valve, and acquiring the pressure sensor at the medium pressure air guiding port in real time. Feedback air pressure value;

When the difference between the target medium pressure value and the air guiding pressure value is large, controlling the third electronic expansion valve to close, and increasing the opening degree of the second electronic expansion valve;

Controlling the second electronic expansion valve to close or reduce the opening degree of the second electronic expansion valve when the difference between the target intermediate pressure value and the pilot gas pressure value is small, and reducing the third The opening of the electronic expansion valve.
The back pressure adjusting method of an air conditioning system according to claim 8 or 9, wherein the controller acquires an intake pressure value at the intake port, an exhaust pressure value at the exhaust port, and The step of the gas pressure value at the medium pressure air outlet further includes:

Calculating a pressure ratio between the exhaust pressure value and the inspiratory pressure value;

When the pressure ratio value satisfies a predetermined range, acquiring a target medium pressure value corresponding to the pressure ratio value;

Adjusting the opening degree of the second electronic expansion valve according to the target medium pressure value until the air guiding pressure value at the medium pressure air guiding port reaches the target intermediate pressure value.
The back pressure adjusting method of an air conditioning system according to claim 8 or 9, wherein the controller acquires an intake pressure value at the intake port, an exhaust pressure value at the exhaust port, and The step of the gas pressure value at the medium pressure air outlet further includes:

When the exhaust pressure value and the inspiratory pressure value satisfy a predetermined range, acquiring a corresponding target medium pressure value;

Adjusting the opening degree of the second electronic expansion valve according to the target medium pressure value until the air guiding pressure value at the medium pressure air guiding port reaches the target intermediate pressure value.
A scroll compressor, comprising: a housing; and an air inlet, an exhaust port and a medium pressure air port provided on the housing, the air inlet and the air conditioning system One end of the evaporator is in communication, and the exhaust port is in communication with one end of a condenser of the air conditioning system, the medium pressure air port for communicating the evaporator and the other end of the condenser.