Method and system for restraining temperature-reaching shutdown by using bypass loop

Abstract

The invention provides a method and system for restraining temperature-up shutdown by applying a bypass loop, an exhaust pipe of a compressor is branched, and an expansion valve is arranged on a branch. The method comprises the steps that the room temperature and the exhaust temperature of the compressor are obtained; the current rotating speed of the compressor is obtained, and a first rotating speed is obtained; and the opening degree of the expansion valve is controlled according to the room temperature, the exhaust temperature and the rotating speed. According to the invention, even at low load, the refrigerant circulation amount of the compressor can be ensured, and the temperature-up shutdown can be inhibited at the same time. The indoor temperature change is reduced, and the comfort is prevented from being reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a method and system for suppressing temperature shutdown by using a bypass loop. Background Art

[0002] In air conditioners, the air conditioning capacity increases at low loads, and sometimes the set temperature is exceeded. There is a temperature-controlled shutdown control that stops the air conditioning and restores the exceeded temperature. However, the temperature-controlled shutdown control requires time to restart in order to temporarily stop the air conditioner. Because a certain capacity is output for restarting, the room temperature is unstable, reducing comfort. In modern homes, especially, the insulation performance has been improved, and air conditioners are mostly operated at low loads. Therefore, measures have been taken to reduce the speed of the compressor, reduce the air conditioning capacity, and reduce the frequency of entering the temperature-controlled shutdown. In air conditioners with small capacity, if the speed of the compressor is reduced, the refrigerant circulation volume is too small, so sometimes the heat generated by the compressor motor cannot be completely cooled. As a result, the temperature of the motor rises, sometimes shortening the life of the compressor. Summary of the invention

[0003] Therefore, the embodiment of the present invention provides a method and system for suppressing overtemperature shutdown by using a bypass circuit, which can suppress overtemperature shutdown while ensuring the refrigerant circulation volume of the compressor even at low load, thereby reducing indoor temperature changes and preventing a decrease in comfort.

[0004] To solve the above problems, the present invention provides a method for suppressing temperature shutdown by using a bypass loop, comprising: branching the exhaust pipe of the compressor and setting an expansion valve on the branch; obtaining the room temperature and the exhaust temperature of the compressor; obtaining the current speed of the compressor to obtain a first speed; and controlling the opening of the expansion valve according to the room temperature, exhaust temperature and speed.

[0005] Compared with the prior art, the technical effect achieved by adopting this technical scheme is as follows: by controlling the opening of the expansion valve according to the room temperature, the exhaust temperature and the compressor speed, and by setting the exhaust pipe branch of the compressor, the flow rate of the refrigerant in the compressor can be controlled according to the current environment, thereby making the circulation of the refrigerant more reasonable when the room temperature is unstable and the air conditioner is in a low-load state, while also ensuring the operating stability of the air conditioner, reducing indoor temperature changes, avoiding the situation where the exhaust temperature of the compressor becomes high, and improving the comfort of using the air conditioner.

[0006] In one example of the present invention, controlling the expansion valve according to the room temperature, exhaust temperature and rotation speed also includes: obtaining the minimum rotation speed at which the compressor can operate stably; comparing the minimum rotation speed with the first rotation speed to obtain a comparison result; and controlling the expansion valve according to the comparison result and the room temperature and exhaust temperature.

[0007] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by obtaining the minimum operating speed of the compressor, and then by comparing the minimum speed with the current speed of the compressor, the expansion valve can be controlled when the compressor reaches the lowest operating state, thereby better controlling the flow of the refrigerant, and at the same time avoiding the situation where the heat generated by the compressor motor cannot be completely cooled, thereby ensuring the stable operation of the motor, thereby avoiding shortening the service life of the compressor, and also improving the safety of the air conditioner.

[0008] In one example of the present invention, controlling the expansion valve according to the comparison result and the room temperature and the exhaust temperature also includes: when the first speed is greater than the minimum speed, controlling the expansion valve to be fully closed; when the first speed is equal to the minimum speed, obtaining the current target air-conditioning mode to obtain the target mode; and controlling the expansion valve according to the target mode room temperature and the exhaust temperature.

[0009] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by setting the expansion valve to be fully closed when the first speed is greater than the minimum speed, it is indicated that the current refrigerant circulation is normal and no control is required, and when the first speed is equal to the minimum speed, corresponding control is performed according to the air-conditioning mode, so that the expansion valve is controlled according to different situations, making the control of the expansion valve more precise and in line with reality, thereby making the state control of the compressor in the air-conditioning more reasonable and scientific, avoiding situations that affect the life of the compressor.

[0010] In one example of the present invention, controlling the expansion valve according to the target mode room temperature and exhaust temperature also includes: when the target mode is cooling; obtaining the current opening of the expansion valve as a first opening; obtaining a first room temperature change opening and a first exhaust change opening; and controlling the expansion valve opening according to the first opening, the first room temperature change opening and the first exhaust change opening.

[0011] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: when set in cooling mode, the opening of the expansion valve is controlled by changing the opening of the first room temperature and the opening of the first exhaust, so that the opening control of the expansion valve is more in line with the actual situation, and the room temperature and exhaust temperature can better reflect the current air-conditioning usage, so that the air-conditioning compressor can be better controlled to control the current room temperature, thereby ensuring the stability of the room temperature, ensuring the normal operation of the compressor, and avoiding the situation of temperature shutdown, thereby improving the comfort of the air conditioner.

[0012] In one embodiment of the present invention, controlling the expansion valve opening according to the first opening, the first room temperature change opening, and the first exhaust change opening also includes: setting the room temperature to be achieved in the cooling mode as the first target room temperature; obtaining the room temperature at time t as the first room temperature, and obtaining the room temperature at time t-1 as the second room temperature; then the first target temperature difference at time t = the first target room temperature - the first room temperature, and the second target temperature difference at time t-1 = the first target room temperature - the second room temperature; the first room temperature change opening = Pa × (first target temperature difference - second target temperature difference) + Ia × first target temperature difference; setting the exhaust temperature to be achieved in the cooling mode as The first target exhaust temperature; the exhaust temperature at time t is recorded as the first exhaust temperature, and the exhaust temperature at time t-1 is recorded as the second exhaust temperature; then the first target exhaust temperature difference at time t = the first target exhaust temperature - the first exhaust temperature, and the second target exhaust temperature difference at time t-1 = the first target exhaust temperature - the second exhaust temperature; the first exhaust change opening = Pd×(first target exhaust temperature difference - second target exhaust temperature difference)+Id×first target exhaust temperature difference; then the expansion valve opening = the first opening + (α×first room temperature change opening+β×first exhaust change opening), where α, β, Pa, Ia, Pd, ld>0.

[0013] Compared with the prior art, the technical effect achieved by adopting the technical scheme is as follows: by setting the difference between the room temperature and the target room temperature at two moments, the first room temperature change opening is obtained. In this way, the first room temperature change opening can better fit the actual use of the current compressor, thereby making the subsequent adjustment of the expansion valve more reasonable. At the same time, the difference between the exhaust temperature at two moments and the target exhaust temperature is obtained, and then the first exhaust change opening is calculated, and then the exhaust temperature is used to better reflect the actual operating conditions inside the current air conditioner, so that the expansion valve can be better controlled according to the current situation. At the same time, the two change openings are finally combined to control the expansion valve opening, so that the expansion valve opening control is more reasonable, ensuring the stable operation of the compressor, ensuring the refrigerant circulation volume of the compressor while suppressing the temperature shutdown, reducing the temperature changes in the room, and improving the comfort.

[0014] In one example of the present invention, when the target mode is heating; the current opening of the expansion valve is obtained and recorded as the second opening; the second room temperature change opening and the second exhaust change opening are obtained; the expansion valve opening is controlled according to the second opening, the second room temperature change opening and the second exhaust change opening.

[0015] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by setting different expansion valve opening controls when the target mode is heating, more practical controls can be performed under different circumstances in different modes, making the compressor in the air conditioner run more stably, ensuring that the room temperature does not change too quickly, resulting in a decrease in the user experience.

[0016] In one embodiment of the present invention, controlling the expansion valve opening according to the second opening and the second room temperature change opening and the second exhaust change opening also includes: setting the room temperature to be achieved in the heating mode as the second target room temperature; obtaining the room temperature at time t as the third room temperature, and obtaining the room temperature at time t-1 as the fourth room temperature; then the third target temperature difference at time t = the third room temperature - the second target room temperature, and the fourth target temperature difference at time t-1 = the fourth room temperature - the second target room temperature; the second room temperature change opening = Pa × (third target temperature difference - fourth target temperature difference) + Ia × third target temperature difference; setting the exhaust temperature to be achieved in the heating mode as The second target exhaust temperature; the exhaust temperature at time t is recorded as the third exhaust temperature, and the exhaust temperature at time t-1 is recorded as the fourth exhaust temperature; the third target exhaust temperature difference at time t = the second target exhaust temperature - the third exhaust temperature, and the fourth target exhaust temperature difference at time t-1 = the second target exhaust temperature - the fourth exhaust temperature; the second exhaust change opening = Pd×(the third target exhaust temperature difference - the fourth target exhaust temperature difference)+Id×the third target exhaust temperature difference; the expansion valve opening = the first opening + (α×the second room temperature change opening+β×the second exhaust change opening), where α, β, Pa, Ia, Pd, ld>0.

[0017] Compared with the prior art, the technical effect achieved by adopting this technical scheme is as follows: by setting the difference between the room temperature and the target room temperature at two moments, and then calculating the second room temperature change opening, the compressor refrigerant flow control in the heating mode is more reasonable, and the room temperature stability can be better guaranteed in the heating mode. At the same time, the exhaust temperature difference at two moments is set to be obtained, and then the second exhaust change opening is calculated, so as to calculate and control the expansion valve opening, which ensures the operating stability of the air conditioner in the heating mode, improves the operating stability of the compressor, and can better suppress temperature shutdown.

[0018] The present invention also provides a system that uses a bypass circuit to suppress temperature shutdown. The system is adaptable to any of the methods described above, and the system includes: a compressor; a four-way valve, the four-way valve connecting the compressor and a first heat exchanger, the first heat exchanger is also connected to a second heat exchanger; the second heat exchanger is connected to the compressor via the four-way valve; a bypass circuit, the bypass circuit is provided between the compressor and the second heat exchanger, and the bypass circuit is used to control the refrigerant flow rate.

[0019] Compared with the prior art, the technical effect achieved by adopting this technical solution is: by adding a bypass loop to the system loop formed by the compressor, the four-way valve and the two heat exchangers, the refrigerant discharged from the compressor flows to the indoor unit through the outdoor heat exchanger through the bypass loop, generating two flows, a flow returning to the compressor and a flow through the bypass loop, thereby ensuring that even at low load, the compressor refrigerant circulation volume can be ensured while suppressing temperature shutdown. Reduce indoor temperature changes and prevent a decrease in comfort.

[0020] In one example of the present invention, the first end of the bypass loop is arranged between the compressor and the four-way valve, and the second end is arranged between the second heat exchanger and the compressor. The bypass loop includes: a capillary tube and a valve body, the capillary tube is arranged near the first end, and the valve body is near the second end.

[0021] Compared with the prior art, the technical effect achieved by adopting this technical solution is: by setting a bypass circuit consisting of a capillary tube and a valve body, and the valve body is close to the second end, the valve body can better control the refrigerant flow in the diversion, thereby better ensuring the normal operation of the compressor.

[0022] In one example of the present invention, the valve body may be an expansion valve or a solenoid valve.

[0023] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by providing two options for the valve body, the selection range is wider, and different valve bodies can be selected to adapt to different situations, making it more practical.

[0024] After adopting the technical solution of the present invention, the following technical effects can be achieved:

[0025] (1) By setting the opening of the expansion valve according to the room temperature, the exhaust temperature and the compressor speed, and by setting the exhaust pipe branch of the compressor, the flow of the refrigerant in the compressor can be controlled according to the current environment, so that when the room temperature is unstable and the air conditioner is in a low load state, the circulation of the refrigerant can be more reasonable, and the operation stability of the air conditioner can be guaranteed, the indoor temperature change can be reduced, and the exhaust temperature of the compressor can be avoided from becoming high, thereby improving the comfort of the air conditioner;

[0026] (2) By adding a bypass circuit to the system circuit formed by the compressor, four-way valve and two heat exchangers, the refrigerant discharged from the compressor flows to the indoor unit through the outdoor heat exchanger through the bypass circuit, generating two flows: the flow returning to the compressor and the flow through the bypass circuit. This ensures that even at low loads, the compressor refrigerant circulation volume can be ensured while suppressing over-temperature shutdown. Reduce indoor temperature changes and prevent a decrease in comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1A flowchart of a method for applying a bypass loop to suppress warm shutdown is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] [First embodiment]

[0031] See also Figure 1 The present invention provides a method for suppressing temperature shutdown by using a bypass circuit, wherein an exhaust pipe of a branch compressor is provided with an expansion valve on the branch line, comprising:

[0032] Step S100: Acquire room temperature and exhaust temperature of the compressor;

[0033] Step S200: acquiring the current rotation speed of the compressor to obtain a first rotation speed;

[0034] Step S300: Control the opening of the expansion valve according to the room temperature, exhaust temperature and rotation speed.

[0035] Specifically, the bypass circuit is composed of a circuit in which a capillary tube and an expansion valve are connected in series. In a small-capacity air conditioner (rated cooling capacity below 7kW), the amount of refrigerant flowing in the bypass circuit decreases, so the flow rate cannot be controlled only by the expansion valve. Therefore, the capillary tubes are connected in series to reduce the differential pressure before and after the expansion valve, so that control can be performed even in the case of low flow.

[0036] Preferably, by controlling the opening of the expansion valve according to the room temperature, the exhaust temperature and the compressor speed, and by setting a branch of the exhaust pipe of the compressor, the flow rate of the refrigerant in the compressor can be controlled according to the current environment, thereby making the circulation of the refrigerant more reasonable when the room temperature is unstable and the air conditioner is in a low load state. At the same time, it can also ensure the operating stability of the air conditioner, reduce the temperature change in the room, avoid the situation where the exhaust temperature of the compressor becomes high, and improve the comfort of using the air conditioner.

[0037] Specifically, controlling the expansion valve according to the room temperature, exhaust temperature and speed also includes: obtaining the minimum speed at which the compressor can operate stably; comparing the minimum speed with the first speed to obtain a comparison result; and controlling the expansion valve according to the comparison result and the room temperature and exhaust temperature.

[0038] Preferably, by obtaining the minimum operating speed of the compressor and then comparing the minimum speed with the current speed of the compressor, the expansion valve can be controlled when the compressor reaches the lowest operating state, thereby better controlling the flow of the refrigerant and avoiding the situation where the heat generated by the compressor motor cannot be completely cooled, thereby ensuring the stable operation of the motor, thereby avoiding shortening the service life of the compressor and improving the safety of the air conditioner.

[0039] Specifically, controlling the expansion valve according to the comparison result and the room temperature and the exhaust temperature also includes: when the first speed is greater than the minimum speed, controlling the expansion valve to be fully closed; when the first speed is equal to the minimum speed, obtaining the current target air-conditioning mode to obtain the target mode; and controlling the expansion valve according to the target mode room temperature and the exhaust temperature.

[0040] Preferably, by setting the expansion valve to be fully closed when the first speed is greater than the minimum speed, it is indicated that the current refrigerant circulation is normal and no control is required, and when the first speed is equal to the minimum speed, corresponding control is performed according to the air-conditioning mode, so that the expansion valve can be controlled according to different situations, making the control of the expansion valve more precise and practical, thereby making the state control of the compressor in the air-conditioning more reasonable and scientific, avoiding situations that affect the life of the compressor.

[0041] Specifically, controlling the expansion valve according to the target mode room temperature and exhaust temperature also includes: when the target mode is cooling; obtaining the current opening of the expansion valve and recording it as the first opening; obtaining the first room temperature change opening and the first exhaust change opening; controlling the expansion valve opening according to the first opening, the first room temperature change opening and the first exhaust change opening.

[0042] Preferably, when set in cooling mode, the opening of the expansion valve is controlled by changing the first room temperature opening and the first exhaust opening, so that the opening control of the expansion valve is more in line with the actual situation, and the room temperature and exhaust temperature can better reflect the current air-conditioning usage, so that the air-conditioning compressor can be better controlled to control the current room temperature, thereby ensuring the stability of the room temperature, ensuring the normal operation of the compressor, and avoiding the situation of temperature shutdown, thereby improving the comfort of the air conditioner.

[0043] Specifically, controlling the expansion valve opening according to the first opening, the first room temperature change opening, and the first exhaust change opening also includes: setting the room temperature to be achieved in the cooling mode as the first target room temperature; obtaining the room temperature at time t as the first room temperature, and obtaining the room temperature at time t-1 as the second room temperature; then the first target temperature difference at time t = the first target room temperature - the first room temperature, and the second target temperature difference at time t-1 = the first target room temperature - the second room temperature; the first room temperature change opening = Pa × (first target temperature difference - second target temperature difference) + Ia × first target temperature difference; setting the exhaust temperature to be achieved in the cooling mode as The first target exhaust temperature; the exhaust temperature at time t is recorded as the first exhaust temperature, and the exhaust temperature at time t-1 is recorded as the second exhaust temperature; then the first target exhaust temperature difference at time t = the first target exhaust temperature - the first exhaust temperature, and the second target exhaust temperature difference at time t-1 = the first target exhaust temperature - the second exhaust temperature; the first exhaust change opening = Pd×(first target exhaust temperature difference - second target exhaust temperature difference)+Id×first target exhaust temperature difference; then the expansion valve opening = the first opening + (α×first room temperature change opening+β×first exhaust change opening), where α, β, Pa, Ia>0.

[0044] Specifically, Pa, Ia, Pd, and ld are constant values ​​determined experimentally, and α and β are function values ​​of exhaust superheat.

[0045] Preferably, the first room temperature change opening is obtained by setting the difference between the room temperature and the target room temperature at two moments. In this way, the first room temperature change opening can better fit the actual use of the current compressor, thereby making the subsequent adjustment of the expansion valve more reasonable. At the same time, the difference between the exhaust temperature at two moments and the target exhaust temperature is obtained, and then the first exhaust change opening is calculated, and then the exhaust temperature is used to better reflect the actual operating conditions inside the current air conditioner, so that the expansion valve can be better controlled according to the current situation. Finally, the two change openings are combined to control the expansion valve opening, so that the expansion valve opening control is more reasonable, ensuring the stable operation of the compressor, ensuring the refrigerant circulation amount of the compressor while suppressing the temperature shutdown, reducing the temperature change in the room, and improving the comfort.

[0046] Specifically, when the target mode is heating; obtain the current opening of the expansion valve and record it as the second opening; obtain the second room temperature change opening and the second exhaust change opening; control the expansion valve opening according to the second opening, the second room temperature change opening and the second exhaust change opening.

[0047] Preferably, by setting different expansion valve opening controls when the target mode is heating, more practical controls can be performed under different conditions in different modes, making the compressor in the air conditioner run more stably and ensuring that the room temperature does not change too quickly, resulting in a decrease in the user experience.

[0048] Specifically, controlling the expansion valve opening according to the second opening degree and the second room temperature change opening degree and the second exhaust change opening degree also includes: setting the room temperature to be achieved in the heating mode as the second target room temperature; obtaining the room temperature at time t as the third room temperature, and obtaining the room temperature at time t-1 as the fourth room temperature; then the third target temperature difference at time t = the third room temperature - the second target room temperature, and the fourth target temperature difference at time t-1 = the fourth room temperature - the second target room temperature; the second room temperature change opening degree = Pa × (third target temperature difference - fourth target temperature difference) + Ia × third target temperature difference; setting the exhaust temperature to be achieved in the heating mode as The second target exhaust temperature; the exhaust temperature at time t is recorded as the third exhaust temperature, and the exhaust temperature at time t-1 is recorded as the fourth exhaust temperature; the third target exhaust temperature difference at time t = the second target exhaust temperature - the third exhaust temperature, and the fourth target exhaust temperature difference at time t-1 = the second target exhaust temperature - the fourth exhaust temperature; the second exhaust change opening = Pd×(the third target exhaust temperature difference - the fourth target exhaust temperature difference)+Id×the third target exhaust temperature difference; the expansion valve opening = the first opening + (α×the second room temperature change opening+β×the second exhaust change opening), where α, β, Pa, Ia>0.

[0049] Preferably, by setting the difference between the room temperature and the target room temperature at two moments to be obtained, and then calculating the second room temperature change opening, the compressor refrigerant flow control in the heating mode is made more reasonable, and the stability of the room temperature in the heating mode can be better guaranteed. At the same time, the exhaust temperature difference at two moments is set to be obtained, and then the second exhaust change opening is calculated, so as to calculate and control the expansion valve opening, which ensures the operating stability of the air conditioner in the heating mode, improves the operating stability of the compressor, and can better suppress the temperature shutdown.

[0050] Preferably, when the expansion valve is replaced with a solenoid valve, the solenoid valve is opened when the frequency of entering the warm shutdown is more than once in 15 minutes. However, the solenoid valve is closed when the exhaust gas temperature exceeds 105°C.

[0051] The present invention also provides a system that uses a bypass circuit to suppress temperature shutdown. The system is adaptable to any of the methods described above, and the system includes: a compressor; a four-way valve, the four-way valve connecting the compressor and a first heat exchanger, the first heat exchanger is also connected to a second heat exchanger; the second heat exchanger is connected to the compressor via the four-way valve; a bypass circuit, the bypass circuit is provided between the compressor and the second heat exchanger, and the bypass circuit is used to control the refrigerant flow rate.

[0052] Preferably, an air conditioner having the structural feature of a bypass circuit with a branched compressor exhaust pipe, one path being a four-way valve and the other being a capillary tube, returning the compressor suction air through an expansion valve; another example is an air conditioner characterized by connecting the outlet piping of the bypass circuit between the four-way valve and the maintenance valve (gas side); another example is an air conditioner characterized by connecting the inlet piping of the bypass circuit between the four-way valve and the heat exchanger; another example is an air conditioner characterized by connecting the inlet piping of the bypass circuit between the four-way valve and the heat exchanger, and connecting the outlet piping between the four-way valve and the maintenance valve (gas side).

[0053] Preferably, another example is an air conditioner characterized by a structure of an expansion valve and a capillary tube from the upstream side of the bypass loop; another example is an air conditioner characterized by a structure of a capillary tube, an expansion valve and a capillary tube from the upstream side of the bypass loop.

[0054] Preferably, a bypass circuit is added to the system circuit formed by the compressor, the four-way valve and the two heat exchangers, so that the refrigerant discharged from the compressor flows to the indoor unit through the outdoor heat exchanger through the bypass circuit, generating two flows, one returning to the compressor and the other flowing through the bypass circuit, thereby ensuring that the compressor refrigerant circulation volume is ensured even at low load while suppressing temperature shutdown, reducing indoor temperature changes and preventing a decrease in comfort.

[0055] Specifically, the first end of the bypass loop is arranged between the compressor and the four-way valve, and the second end is arranged between the second heat exchanger and the compressor. The bypass loop includes: a capillary tube and a valve body. The capillary tube is arranged near the first end, and the valve body is near the second end.

[0056] Preferably, by providing a capillary tube and a valve body in the bypass circuit, and the valve body is close to the second end, the valve body can better control the refrigerant flow in the diversion, thereby better ensuring the normal operation of the compressor.

[0057] Specifically, the valve body may be an expansion valve or a solenoid valve.

[0058] Preferably, by providing two options for the valve body, the selection range is expanded, and different valve bodies can be selected to adapt to different situations, making it more practical.

[0059] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for suppressing temperature shutdown by using a bypass circuit, wherein the exhaust pipe of a branch compressor is provided with an expansion valve on the branch line, characterized in that: include: Acquiring room temperature and exhaust temperature of the compressor; Acquire the current rotation speed of the compressor to obtain a first rotation speed; The opening degree of the expansion valve is controlled according to the room temperature, the exhaust temperature and the rotation speed.

2. The method of using a bypass loop to suppress temperature shutdown according to claim 1, characterized in that: The controlling of the expansion valve according to the room temperature, the exhaust temperature and the rotation speed further comprises: Obtaining the minimum speed at which the compressor can operate stably; comparing the minimum rotation speed with the first rotation speed to obtain a comparison result; The expansion valve is controlled according to the comparison result, the room temperature, and the exhaust gas temperature.

3. The method of using a bypass loop to suppress temperature shutdown according to claim 2, characterized in that: The controlling the expansion valve according to the comparison result and the room temperature and the exhaust temperature further comprises: When the first speed is greater than the minimum speed, the expansion valve is controlled to be fully closed; When the first speed is equal to the minimum speed, the mode of the current target air conditioner is acquired to obtain a target mode; The expansion valve is controlled according to the target mode, the room temperature and the exhaust gas temperature.

4. The method of using a bypass loop to suppress temperature shutdown according to claim 3, characterized in that: The controlling the expansion valve according to the target mode, the room temperature and the exhaust temperature further comprises: When the target mode is cooling; Obtaining the current opening of the expansion valve and recording it as a first opening; Obtaining a first room temperature change opening degree and a first exhaust change opening degree; The expansion valve opening is controlled according to the first opening, the first room temperature change opening, and the first exhaust gas change opening.

5. The method of using a bypass loop to suppress temperature shutdown according to claim 4, characterized in that: The controlling the expansion valve opening according to the first opening, the first room temperature change opening, and the first exhaust change opening further comprises: Set the room temperature to be reached in cooling mode as the first target room temperature; The room temperature at time t is recorded as the first room temperature, and the room temperature at time t-1 is recorded as the second room temperature; Then the first target temperature difference at the time t = the first target room temperature - the first room temperature, and the second target temperature difference at the time t-1 = the first target room temperature - the second room temperature; The first room temperature change opening degree = Pa × (the first target temperature difference - the second target temperature difference) + Ia × the first target temperature difference; Setting the exhaust temperature to be achieved in the cooling mode as the first target exhaust temperature; The exhaust temperature at the time t is obtained and recorded as the first exhaust temperature, and the exhaust temperature at the time t-1 is obtained and recorded as the second exhaust temperature; Then the first target exhaust temperature difference at the time t = the first target exhaust temperature - the first exhaust temperature, and the second target exhaust temperature difference at the time t-1 = the first target exhaust temperature - the second exhaust temperature; The first exhaust change opening degree=Pd×(the first target exhaust temperature difference−the second target exhaust temperature difference)+Id×the first target exhaust temperature difference; Then the expansion valve opening = the first opening + (α×the first room temperature change opening+β×the first exhaust change opening), where α, β, Pa, Ia, Pd, ld>0.

6. The method of using a bypass loop to suppress temperature shutdown according to claim 3, characterized in that: When the target mode is heating; Obtaining the current opening of the expansion valve and recording it as a second opening; Obtaining a second room temperature change opening degree and a second exhaust change opening degree; The expansion valve opening is controlled according to the second opening, the second room temperature change opening, and the second exhaust gas change opening.

7. The method for suppressing temperature shutdown by using a bypass loop according to claim 6, characterized in that: Controlling the expansion valve opening according to the second opening, the second room temperature change opening, and the second exhaust change opening further includes: Set the room temperature to be achieved in heating mode as the second target room temperature; The room temperature at time t is recorded as the third room temperature, and the room temperature at time t-1 is recorded as the fourth room temperature; Then the third target temperature difference at the time t = the third room temperature - the second target room temperature, and the fourth target temperature difference at the time t-1 = the fourth room temperature - the second target room temperature; The second room temperature change opening degree = Pa × (the third target temperature difference - the fourth target temperature difference) + Ia × the third target temperature difference; Setting the exhaust temperature to be achieved in the heating mode as the second target exhaust temperature; The exhaust temperature at the time t is obtained and recorded as the third exhaust temperature, and the exhaust temperature at the time t-1 is obtained and recorded as the fourth exhaust temperature; Then the third target exhaust temperature difference at the time t = the second target exhaust temperature - the third exhaust temperature, and the fourth target exhaust temperature difference at the time t-1 = the second target exhaust temperature - the fourth exhaust temperature; The second exhaust change opening degree=Pd×(the third target exhaust temperature difference−the fourth target exhaust temperature difference)+Id×the third target exhaust temperature difference; Then the expansion valve opening = the first opening + (α×the second room temperature change opening+β×the second exhaust change opening), where α, β, Pa, Ia, Pd, ld>0.

8. A system for suppressing thermal shutdown by using a bypass loop, the system being adapted to the method according to any one of claims 1 to 7, characterized in that: The system comprises: compressor; A four-way valve, the four-way valve connecting the compressor and the first heat exchanger, the first heat exchanger also connecting the second heat exchanger; The second heat exchanger is connected to the compressor via the four-way valve; A bypass circuit is provided between the compressor and the second heat exchanger, and the bypass circuit is used to control the flow rate of the refrigerant.

9. The method for applying a bypass loop to suppress temperature shutdown according to claim 8, characterized in that: The first end of the bypass loop is arranged between the compressor and the four-way valve, and the second end is arranged between the second heat exchanger and the compressor. The bypass loop includes: a capillary tube and a valve body. The capillary tube is arranged close to the first end, and the valve body is close to the second end.

10. The method of using a bypass loop to suppress temperature shutdown according to claim 8, characterized in that: The system further comprises: The valve body may be an expansion valve or a solenoid valve.

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