Air conditioner

Abstract

The invention discloses an air conditioner. The air conditioner comprises a refrigerant circulating system, a pressure sensor, a first temperature sensor, a second temperature sensor and a controller. The refrigerant circulating system comprises a compressor, a throttling device, a switching device, an indoor heat exchanger and an outdoor heat exchanger; the controller is configured to: obtain a run time of the compressor; obtaining an exhaust superheat degree according to the exhaust temperature, and obtaining an outdoor heat exchanger temperature difference according to the outdoor heat exchanger temperature; and when the running time of the compressor, the exhaust superheat degree, the refrigerant pressure and the temperature difference of the outdoor heat exchanger meet the fluorine-lacking protection conditions, a fluorine-lacking protection strategy is executed. By the adoption of the air conditioner, when the compressor operates stably, more relevant parameters such as the refrigerant pressure, the compressor exhaust superheat degree and the outdoor heat exchanger temperature difference are combined, judgment condition fusion is carried out, whether the refrigerant circulating system of the air conditioner lacks refrigerants or not is comprehensively judged, judgment accuracy is improved, and misjudgment and missed judgment are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to an air conditioner. Background Art

[0002] In the prior art, the cooling and heating functions of the air conditioner depend on the circulation of refrigerant. Due to installation and other reasons, there is a risk of refrigerant leakage in the air conditioner. When the refrigerant leaks, it is necessary to replenish the refrigerant in time, otherwise the cooling and heating effects of the air conditioner will be affected. In serious cases, the compressor will be damaged. Currently, the judgment of refrigerant leakage in the refrigerant circulation system of the air conditioner is mostly based on the calculation of the refrigerant pressure and the sensor temperature value to couple and judge whether the air conditioner is short of fluorine. The judgment method is single and prone to misjudgment and omission. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to provide an air conditioner, which can comprehensively judge whether the refrigerant circulation system of the air conditioner lacks refrigerant by combining the conditions of refrigerant pressure, compressor exhaust superheat and outdoor heat exchanger temperature difference when the compressor is running stably, thereby improving the judgment accuracy and avoiding misjudgment and missed judgment.

[0004] In order to solve the above problems, the first aspect of the present invention provides an air conditioner, comprising: a refrigerant circulation system, the refrigerant circulation system comprising a compressor, a throttling device, a switching device, an indoor heat exchanger and an outdoor heat exchanger, the switching device being respectively connected to the outdoor heat exchanger, the indoor heat exchanger, the exhaust port of the compressor and the return air port of the compressor; a pressure sensor, the pressure sensor being arranged on the connecting pipeline between the switching device and the indoor heat exchanger, for detecting the refrigerant pressure in the refrigerant circulation system; a first temperature sensor being arranged at the exhaust port of the compressor, for detecting the exhaust temperature; a second temperature sensor being arranged at the outdoor heat exchanger, for detecting the temperature of the outdoor heat exchanger; a controller, the controller being connected to the pressure sensor, the first temperature sensor and the second temperature sensor, the controller being configured to: obtain the running time of the compressor; obtain the exhaust superheat according to the exhaust temperature, and obtain the outdoor heat exchanger temperature difference according to the outdoor heat exchanger temperature; and execute the fluorine deficiency protection strategy when the running time of the compressor, the exhaust superheat, the refrigerant pressure and the outdoor heat exchanger temperature difference meet the fluorine deficiency protection conditions.

[0005] According to the air conditioner of the embodiment of the present invention, when the compressor is running stably, the refrigerant pressure in the refrigerant circulation system is obtained through the pressure sensor, the exhaust temperature and the outdoor heat exchanger temperature are obtained through the first temperature sensor and the second temperature sensor, and the controller comprehensively determines whether the refrigerant circulation system of the air conditioner lacks refrigerant based on the compressor running time, refrigerant pressure, compressor exhaust superheat and outdoor heat exchanger temperature difference, thereby improving the accuracy of judgment and avoiding misjudgment and missed judgment.

[0006] In some embodiments, the fluorine deficiency protection conditions include: the running time of the compressor reaches a first preset time threshold; the exhaust superheat exceeds the preset superheat threshold; the outdoor heat exchanger temperature difference is lower than the preset temperature difference threshold; the refrigerant pressure is lower than the preset pressure threshold.

[0007] The above technical solution has the following advantages or beneficial effects: whether the air conditioner is short of fluorine can be determined by the above judgment conditions. When the above judgment conditions are met, fluorine deficiency protection is performed to avoid misjudgment and improve the accuracy of fluorine deficiency protection.

[0008] In some embodiments, the outdoor heat exchanger temperature difference is the temperature difference between the outdoor ambient temperature and the outdoor heat exchanger temperature.

[0009] The above technical solution has the following advantages or beneficial effects: the outdoor heat exchanger temperature difference is determined according to the temperature difference between the outdoor ambient temperature and the outdoor heat exchanger temperature, and whether the air conditioner is short of fluorine is judged by the outdoor heat exchanger temperature difference, thereby improving the accuracy of fluorine deficiency protection.

[0010] In some embodiments, the controller is configured to: judge the refrigerant pressure after the running time of the compressor reaches the first preset time threshold; judge the exhaust superheat and the outdoor heat exchanger temperature difference respectively after determining that the refrigerant pressure is lower than the preset pressure threshold; when the exhaust superheat exceeds the preset superheat threshold and the outdoor heat exchanger temperature difference is lower than the preset temperature difference threshold, determine that the running time of the compressor, the exhaust superheat, the refrigerant pressure and the outdoor heat exchanger temperature difference meet the fluorine deficiency protection condition.

[0011] The above technical solution has the following advantages or beneficial effects: when all the above conditions are met, it is determined that the refrigerant circulation system is lacking in fluorine and fluorine deficiency protection is required, and refrigerant leakage is judged by combining multiple parameters such as refrigerant pressure, exhaust superheat and outdoor heat exchanger temperature difference. The refrigerant leakage judgment is more accurate and can avoid misjudgment or missed judgment.

[0012] In some embodiments, the controller is further configured to: before the fluorine deficiency protection condition is determined, obtain a pressure correction coefficient based on the outdoor ambient temperature, and correct the refrigerant pressure based on the pressure correction coefficient, and / or obtain a superheat correction coefficient based on the outdoor ambient temperature, and correct the exhaust superheat based on the superheat correction coefficient.

[0013] The above technical solution has the following advantages or beneficial effects: the exhaust superheat of different frequencies is corrected according to the superheat correction coefficient, so that the calculated exhaust superheat is more accurate, thereby improving the accuracy of refrigerant leakage judgment.

[0014] In some embodiments, the controller is further configured to: record the duration of the compressor operation time, the exhaust superheat, the refrigerant pressure and the outdoor heat exchanger temperature difference satisfying the fluorine deficiency protection condition; when the duration reaches a second preset time threshold, record it as a fluorine deficiency protection trigger instruction; when a preset number of fluorine deficiency protection trigger instructions are obtained within a preset time period, execute the fluorine deficiency protection strategy.

[0015] The above technical solution has the following advantages or beneficial effects: when the fluorine deficiency protection trigger instruction is detected twice in succession within a preset time period, the fluorine deficiency protection strategy is executed, the air conditioner stops working, and misjudgment is avoided.

[0016] In some embodiments, the controller is further configured to control the compressor to operate at a normal frequency when the refrigerant pressure is higher than the preset pressure threshold or the exhaust superheat does not exceed the preset superheat threshold or the outdoor heat exchanger temperature difference is not lower than the preset temperature difference threshold.

[0017] The above technical solution has the following advantages or beneficial effects: as long as any one of the three conditions is met, the compressor will operate at a normal frequency, and the refrigerant leakage judgment will be more accurate, avoiding misjudgment or missed judgment.

[0018] In some embodiments, when executing the fluorine deficiency protection strategy, the controller is configured to: control the compressor to stop.

[0019] The above technical solution has the following advantages or beneficial effects: after the fluorine deficiency protection strategy is triggered, the controller controls the compressor to shut down to prevent the refrigerant circulation system from continuing to operate in a fluorine deficiency state, thereby avoiding potential damage to the air conditioner.

[0020] In some embodiments, when executing the fluorine deficiency protection strategy, the controller is further configured to: provide a fluorine deficiency fault prompt.

[0021] The above technical solution has the following advantages or beneficial effects: timely notifying the user of the current fluorine deficiency state, so that after-sales personnel can contact the user as soon as possible to solve the fault.

[0022] In some embodiments, the controller is further configured to: exit the fluorine deficiency protection strategy upon receiving a power on / off signal of the air conditioner, or exit the fluorine deficiency protection strategy after the air conditioner is powered on again.

[0023] The above technical solution has the following advantages or beneficial effects: after the air conditioner is powered on again after a power outage, the controller will execute a series of initialization steps to ensure that the air conditioner can start and run correctly.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a perspective view of an air conditioner according to an embodiment of the present invention; Figure 2 is a schematic diagram of an air conditioner according to an embodiment of the present invention; Figure 3 is a structural block diagram of an air conditioner according to an embodiment of the present invention; Figure 4 is a control flow chart of a controller according to one embodiment of the present invention; Figure 5 is a control schematic diagram of an air conditioner according to an embodiment of the present invention; Figure 6 is a schematic diagram of compressor frequency and refrigerant pressure according to an embodiment of the present invention; Figure 7 is a schematic diagram of a correction coefficient of the effect of outdoor ambient temperature on refrigerant pressure according to an embodiment of the present invention; Figure 8 is a schematic diagram of compressor frequency and exhaust superheat according to an embodiment of the present invention; Fig. 9 is a schematic diagram of a correction coefficient of the effect of outdoor ambient temperature on exhaust gas superheat according to an embodiment of the present invention; Fig.10 is a flow chart of fluorine deficiency protection control according to an embodiment of the present invention; Fig.11 Schematic diagram of an air conditioner operation curve according to an embodiment of the present invention.

[0026] Reference numerals: Air conditioner 100; Outdoor unit 1; connecting pipe 2; indoor unit 3; pressure sensor 101; first temperature sensor 102; second temperature sensor 103; controller 104; compressor 111; throttling device 112; switching device 113; indoor heat exchanger 114; outdoor heat exchanger 115. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0028] The air conditioner realizes the cooling and heating cycle of the air conditioner through a refrigerant circulation system.

[0029] The refrigerant circulation system includes a compressor. The compressor is a device that converts low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure refrigerant through work. It is the "heart" of the air-conditioning system and is mainly responsible for compressing and transporting the refrigerant to achieve the function of cooling or heating. In the refrigeration cycle, the compressor extracts the refrigerant from the low-pressure area, compresses it and sends it to the high-pressure area for cooling and condensation, and then enters the evaporator to evaporate and absorb heat after the pressure is reduced by the throttling device, thereby achieving the adjustment of parameters such as temperature and humidity in the room or car.

[0030] The refrigerant circulation system also includes a throttling device, which can be a capillary tube or an expansion valve. The present invention is described with an expansion valve. The expansion valve converts high-temperature and high-pressure liquid refrigerant into low-temperature and low-pressure wet steam by throttling to achieve a refrigeration effect. The expansion valve is mainly installed between the liquid storage tank and the evaporator, and controls the valve flow rate through the heat change at the end of the evaporator, thereby preventing the evaporator area from being underutilized and the occurrence of cylinder knocking.

[0031] The refrigerant circulation system also includes a switching device, which can be a four-way valve. The four-way valve has four channels or connecting pipes and is a key component in the refrigeration and air-conditioning system for changing the flow direction of the refrigerant. The four-way valve can change the flow direction of the air conditioner between cooling and heating conditions; the four-way valve is mainly composed of two parts: an electromagnetic pilot valve and a four-way reversing valve. The electromagnetic pilot valve is composed of a valve bowl, a spring, an iron core and an electromagnetic coil, while the four-way reversing valve is controlled by the electromagnetic pilot valve, and the two are connected by a guide capillary.

[0032] In the air conditioner, the four-way valve usually has four pipe interfaces, among which the D pipe is connected to the exhaust port of the compressor, the S pipe is connected to the return air port of the compressor, the E pipe is connected to the outdoor heat exchanger, and the C pipe is connected to the indoor heat exchanger.

[0033] The refrigerant circulation system also includes an indoor heat exchanger and an outdoor heat exchanger.

[0034] When the air conditioner is in cooling mode, the four-way valve E pipe is connected to the S pipe, and the D pipe is connected to the C pipe, so that the refrigerant comes out of the compressor, passes through the four-way valve D pipe and enters the outdoor heat exchanger (condenser) to dissipate heat, and then becomes a low-temperature and low-pressure liquid through throttling and pressure reduction, and enters the indoor heat exchanger (evaporator) to absorb heat, completing the refrigeration cycle.

[0035] When switched to heating mode, the four-way valve changes position so that the D pipe of the four-way valve is connected to the E pipe, and the C pipe is connected to the S pipe. The refrigerant comes out of the compressor, passes through the D pipe of the four-way valve and enters the indoor heat exchanger (condenser) to release heat, and then undergoes throttling and pressure reduction to become a low-temperature and low-pressure two-phase fluid, and enters the outdoor heat exchanger (evaporator) to absorb heat, completing the heating cycle.

[0036] The outdoor unit of the air conditioner refers to a part of a refrigeration cycle including a compressor and an outdoor heat exchanger, the indoor unit of the air conditioner includes an indoor heat exchanger, and the expansion valve may be provided in the indoor unit or the outdoor unit.

[0037] The indoor heat exchanger and the outdoor heat exchanger function as a condenser or an evaporator. When the indoor heat exchanger functions as a condenser, the air conditioner functions as a heater in a heating mode, and when the indoor heat exchanger functions as an evaporator, the air conditioner functions as a cooler in a cooling mode.

[0038] Air conditioners such as window units, indoor vertical duct units, etc. Figure 1 As shown, the air conditioner 100 includes an indoor unit 3 and an outdoor unit 1. The indoor unit 3 is usually set on the indoor floor, and the outdoor unit 1 is usually set outdoors for heat exchange in the indoor environment. The outdoor unit 1 and the indoor unit 3 are connected by a connecting pipe 2 to perform cooling and heating.

[0039] At present, the judgment of refrigerant leakage of air conditioners is mostly based on the calculation of pressure and sensor temperature values ​​to couple and judge whether the air conditioner is short of fluorine. The judgment method is single and prone to misjudgment and omission.

[0040] In order to solve the above problems, the first aspect of the embodiment of the present invention provides an air conditioner, which can combine more relevant parameters such as refrigerant pressure, compressor exhaust superheat and outdoor heat exchanger temperature difference and integrate judgment conditions when the compressor is running stably, so as to comprehensively judge whether the refrigerant circulation system of the air conditioner lacks refrigerant, improve the accuracy of judgment, and avoid misjudgment and missed judgment.

[0041] like Figure 2 As shown, the refrigerant circulation system in the air conditioner 100 includes a compressor 111, a throttling device 112, a switching device 113, an indoor heat exchanger 114 and an outdoor heat exchanger 115.

[0042] Among them, the switching device 113 is respectively connected to the outdoor heat exchanger 115, the indoor heat exchanger 114, the exhaust port of the compressor 111 and the return air port of the compressor 111. In the present invention, the throttling device 112 can be an expansion valve, and the switching device 113 can be a four-way valve.

[0043] like Figure 2 As shown, the air conditioner 100 also includes a liquid stop valve, a gas stop valve, a one-way valve, a filter and an electronic expansion valve; wherein the liquid stop valve and the gas stop valve are both important components in the air conditioner, and the liquid stop valve and the gas stop valve regulate the flow of the refrigerant by controlling the opening and closing of the valves. The liquid stop valve is usually installed on the pipeline between the outdoor heat exchanger 115 and the throttling device 112, and the flow of the liquid refrigerant is controlled by opening or closing the liquid stop valve. The gas stop valve is installed between the exhaust port of the compressor 111 and the indoor heat exchanger 114, and the flow of the gaseous refrigerant is controlled by opening or closing the gas stop valve; the one-way valve in the air conditioner is a valve that allows the refrigerant to flow in one direction. The one-way valve is a device that allows liquid refrigerant to flow in one direction but prevents it from flowing in the opposite direction. The one-way valve is installed between the outdoor heat exchanger 115 and the throttling device 112 to ensure that the liquid refrigerant can only flow toward the outdoor heat exchanger 115 to avoid backflow caused by gravity or other factors. The electronic expansion valve can adjust the refrigerant flow more accurately to adapt to different operating conditions. The electronic expansion valve can adjust the refrigerant flow in real time to enable the air conditioner to maintain the best energy efficiency ratio under various operating conditions. The filters on both sides of the electronic expansion valve mainly prevent impurities from entering the electronic expansion valve. Due to the presence of the filter, impurities can be effectively prevented from entering the electronic expansion valve, thereby avoiding clogging of the electronic expansion valve and causing a decrease in the refrigeration effect.

[0044] like Figure 2 As shown, the air conditioner 100 includes a pressure sensor 101, which is arranged on the connecting pipeline between the switching device 113 and the indoor heat exchanger 114, and is used to detect the refrigerant pressure in the refrigerant circulation system, so that both cooling and heating can detect the pressure of the indoor heat exchanger, the cooling detection value is the low pressure, and the heating detection value is the high pressure; the first temperature sensor 102 is arranged at the exhaust port of the compressor 111, and is used to detect the exhaust temperature; the second temperature sensor 103 is arranged at the outdoor heat exchanger 115, and is used to detect the temperature of the outdoor heat exchanger 115.

[0045] Specifically, the pressure sensor 101 can be arranged on the connecting pipeline between the switching device 113 and the indoor heat exchanger 114 to monitor the refrigerant pressure of the refrigerant circulation system. The pressure sensor 101 can detect the refrigerant pressure in the pipeline, and then the controller can judge the amount of refrigerant by the change of the refrigerant pressure, thereby ensuring the normal operation of the air-conditioning system.

[0046] like Figure 2As shown, the air conditioner 100 further includes a first temperature sensor 102, which is disposed at the exhaust port of the compressor 111. After obtaining the exhaust port temperature of the compressor 111, the exhaust superheat can be obtained by calculation. When the exhaust superheat is abnormal, the refrigerant circulation system may lack refrigerant.

[0047] like Figure 2 As shown, the air conditioner 100 further includes a second temperature sensor 103, which is disposed at the outdoor heat exchanger 115 and is used to detect the temperature of the outdoor heat exchanger 115. After obtaining the temperature of the outdoor heat exchanger 115, the outdoor heat exchanger temperature is calculated to be different from the outdoor ambient air temperature to obtain the outdoor heat exchanger temperature difference. When the outdoor heat exchanger temperature difference is abnormal, the refrigerant circulation system may lack refrigerant.

[0048] like Figure 3 As shown, the air conditioner 100 further includes a controller 104, which is connected to the pressure sensor 101, the first temperature sensor 102 and the second temperature sensor 103. The controller 104 is the data processing center of the air conditioner, which can perform data analysis and calculation, and provide execution strategies based on the analysis.

[0049] Based on the above air conditioner architecture, refer to Figure 4 As shown, the controller of the air conditioner is configured to perform the following steps S1 to S3.

[0050] Step S1, obtaining the running time of the compressor.

[0051] Specifically, most of the prior art determines whether the air conditioner lacks refrigerant before the air conditioner is operated, but is unable to determine whether the air conditioner lacks refrigerant during operation. The present invention can determine whether the refrigerant circulation system lacks refrigerant during operation of the air conditioner. Since the compressor is the power source of the air conditioner's cooling and heating cycles, the compressor compresses the refrigerant and increases its temperature and pressure during the cooling and heating processes, thereby providing power for the circulation of the refrigerant. Therefore, the operating time of the compressor can be obtained during the operation of the air conditioner, and a timer can be provided to record the working time of the compressor.

[0052] Step S2, obtaining the exhaust gas superheat according to the exhaust gas temperature, and obtaining the outdoor heat exchanger temperature difference according to the outdoor heat exchanger temperature.

[0053] Specifically, since the first temperature sensor is disposed at the exhaust port of the compressor, the exhaust superheat can be obtained by calculation after obtaining the exhaust port temperature of the compressor. The exhaust superheat DSH (Discharge Superheat) is a parameter of the difference between the temperature at the compressor exhaust pipe or the condenser inlet and the saturation temperature corresponding to the actual condensing pressure. The exhaust superheat DSH is equal to the exhaust temperature Td of the compressor minus the saturation temperature corresponding to the condensing temperature Tc, reflecting the degree to which the current temperature exceeds the saturation temperature corresponding to its pressure. The exhaust temperature Td of the compressor can be obtained by the first temperature sensor, and the saturation temperature corresponding to the condensing temperature Tc is obtained by looking up the corresponding refrigerant saturation temperature of the current system high-pressure side pressure value. When the exhaust superheat is abnormal, the refrigerant circulation system may lack refrigerant.

[0054] The outdoor heat exchanger temperature difference usually refers to the difference between the outdoor heat exchanger temperature and the outdoor ambient air temperature. The outdoor ambient air temperature refers to the actual temperature of the outdoor air, which can be obtained by using a temperature sensor installed outdoors. The outdoor heat exchanger temperature can be obtained by a second temperature sensor, such as Figure 2 As shown, the outdoor heat exchanger is provided with two upper and lower second temperature sensors. The outdoor heat exchanger temperature is obtained according to the average value of the two second temperature sensors to reduce the error. The obtained outdoor heat exchanger temperature is subtracted from the outdoor ambient air temperature to obtain the outdoor heat exchanger temperature difference. If the outdoor heat exchanger temperature difference is abnormally large or small, it may be due to the lack of refrigerant in the refrigerant circulation system.

[0055] Step S3, when the compressor operation time, exhaust gas superheat, refrigerant pressure and outdoor heat exchanger temperature difference meet the fluorine deficiency protection conditions, execute the fluorine deficiency protection strategy.

[0056] Specifically, after the compressor in the air conditioner is started, it usually takes some time to reach a stable operating state. This process includes a startup phase, an adjustment phase, and finally enters a continuous and stable operating mode. When the air conditioner is turned on for the first time, the compressor will go through a startup phase, during which the motor accelerates to the working speed. The startup time is generally short, and may only take a few seconds to more than ten seconds. When the compressor starts running, it will try to adjust the indoor temperature to the set value. During this process, the compressor will adjust the speed according to actual needs until the indoor temperature approaches the set temperature. The working state of the compressor will tend to be stable. The whole process takes several minutes to more than ten minutes. Therefore, when judging whether the refrigerant circulation system lacks refrigerant, it is necessary to judge when the compressor is running stably; the refrigerant is a working fluid that transfers heat and produces a refrigeration effect in the refrigerant circulation system of the air conditioner. The refrigerant in the present invention can be Freon. Therefore, when the operating time of the compressor, the exhaust superheat, the refrigerant pressure and the temperature difference of the outdoor heat exchanger meet the fluorine deficiency protection conditions, the fluorine deficiency protection strategy is executed. At this time, the compressor stops working and prompts to avoid affecting the refrigeration effect of the air conditioner and reducing the overall performance and life of the air conditioner.

[0057] For example, the present invention calculates the refrigerant pressure and temperature parameters to accurately determine whether the refrigerant circulation system lacks refrigerant, enters the protection program, protects the refrigerant circulation system, and solves the problem of air conditioner system damage caused by lack of refrigerant in the system. A refrigerant pressure sensor and a sensor for detecting the operating temperature are set in the air conditioner. Through the coupled calculation of the refrigerant pressure and the operating temperature, it is double judged whether the refrigeration system lacks refrigerant. It ensures that the refrigerant circulation system can be judged in time when it lacks refrigerant, reports a fault, and protects the refrigeration system.

[0058] The air conditioner in the present invention can be a variable frequency air conditioner in a 24V communication mode. When controlling the compressor frequency of the variable frequency air conditioner in a 24V communication mode, the 24V communication air conditioner only has switch signals indoors and outdoors, but no code signals, so the indoor unit cannot send parameters and operating status to the outdoor unit. The core idea of ​​the method of the present invention is to set a pressure sensor on the pipeline of the four-way valve connected to the indoor unit, and calculate the operating parameters of the indoor unit evaporator by detecting the operating pressure of the air conditioner refrigerant system to determine the system status. Based on this, the controller can couple the calculation of the refrigerant pressure sensor data and the temperature value detected by the temperature sensor, and combine the operating characteristics of the refrigerant under fluorine deficiency to accurately determine whether the amount of refrigerant in the system is lacking. When the system lacks refrigerant, it can promptly report a fault and stop running, thereby achieving protection for the variable frequency refrigeration system. The control schematic diagram of the air conditioner is shown in FIG. Figure 5 As shown, the controller is mainly composed of a pressure sensor, an air conditioning processor, a temperature sensor, an expansion valve, a compressor, an indoor air conditioner fan, an indoor evaporator and a refrigerant circulation system. According to the air conditioner of the embodiment of the present invention, when the compressor is running stably, the refrigerant pressure in the refrigerant circulation system is obtained through the pressure sensor, the exhaust temperature and the outdoor heat exchanger temperature are obtained through the first temperature sensor and the second temperature sensor, and the controller comprehensively determines whether the refrigerant circulation system of the air conditioner lacks refrigerant based on the compressor running time, refrigerant pressure, compressor exhaust superheat and outdoor heat exchanger temperature difference, thereby improving the accuracy of judgment and avoiding misjudgment and missed judgment.

[0059] In some embodiments, the fluorine deficiency protection conditions include: the compressor operation time reaches a first preset time threshold; the exhaust superheat exceeds a preset superheat threshold; the outdoor heat exchanger temperature difference is lower than a preset temperature difference threshold; and the refrigerant pressure is lower than a preset pressure threshold.

[0060] Specifically, the first preset time threshold can be understood as the time from compressor startup to stable operation. After startup, the compressor usually takes some time to reach a stable operating state. The whole process takes several minutes to more than ten minutes. For example, the first preset time threshold can be 10 minutes, that is, the compressor stably operates 10 minutes after startup; the exhaust superheat plays an important role in the operation and maintenance of the refrigerant circulation system. By monitoring the exhaust superheat, the working state of the compressor, the charge amount of the refrigerant, etc. can be judged. Therefore, when the exhaust superheat exceeds the preset superheat threshold, it is determined that the refrigerant circulation system is short of fluorine. For example, the preset superheat threshold can be 45°C. When the exhaust superheat exceeds 45°C, it is determined that the refrigerant circulation system is short of fluorine; the outdoor heat exchanger temperature difference usually refers to the difference between the outdoor heat exchanger temperature and the outdoor ambient air temperature. If the outdoor heat exchanger If the temperature difference is lower than the preset temperature difference threshold, it may be due to the lack of refrigerant in the refrigerant circulation system. In this case, fluorine deficiency protection is performed. For example, if the temperature difference of the outdoor heat exchanger is lower than 2°C, it is determined that the refrigerant circulation system is lacking fluorine. The refrigerant pressure of the refrigerant circulation system is monitored by a pressure sensor. The pressure sensor can judge the amount of refrigerant by sensing the change in refrigerant pressure. When the refrigerant pressure is lower than the preset pressure threshold, it is determined that the refrigerant circulation system is lacking fluorine. For example, the current pressure sensor detects that the refrigerant pressure is lower than 30% of the preset pressure value, and it is determined that the refrigerant circulation system is lacking fluorine. When the running time of the compressor reaches the first preset time threshold, and the exhaust superheat exceeds the preset superheat threshold, the outdoor heat exchanger temperature difference is lower than the preset temperature difference threshold, and the refrigerant pressure is lower than the preset pressure threshold, it is determined that the refrigerant circulation system is lacking fluorine, and fluorine deficiency protection is performed to avoid misjudgment and improve the accuracy of fluorine deficiency protection.

[0061] In some embodiments, the outdoor heat exchanger temperature difference is the temperature difference between the outdoor ambient temperature and the outdoor heat exchanger temperature.

[0062] Specifically, the outdoor heat exchanger temperature difference generally refers to the difference between the outdoor heat exchanger temperature and the outdoor ambient temperature. The outdoor ambient temperature refers to the actual temperature of the outdoor air, which can be obtained by using a temperature sensor installed outdoors. The outdoor heat exchanger temperature can be obtained by a sensor installed on the outdoor heat exchanger.

[0063] In some embodiments, after the running time of the compressor reaches a first preset time threshold, the refrigerant pressure is judged; after it is determined that the refrigerant pressure is lower than the preset pressure threshold, the exhaust superheat and the outdoor heat exchanger temperature difference are judged respectively; when the exhaust superheat exceeds the preset superheat threshold and the outdoor heat exchanger temperature difference is lower than the preset temperature difference threshold, it is determined that the running time of the compressor, the exhaust superheat, the refrigerant pressure and the outdoor heat exchanger temperature difference meet the fluorine deficiency protection conditions.

[0064] Specifically, after the running time of the compressor reaches a first preset time threshold, that is, after the compressor runs stably, the refrigerant pressure is judged. Since the pressure change is most obvious when the refrigerant is lacking, after the running time of the compressor reaches the first preset time threshold, first judge whether the refrigerant pressure is less than the pressure threshold. If so, make a subsequent judgment. If the refrigerant pressure is not lower than the preset pressure threshold, no subsequent judgment is required. After determining that the refrigerant pressure is lower than the preset pressure threshold, the exhaust superheat and the outdoor heat exchanger temperature difference are judged respectively. When the exhaust superheat exceeds the preset superheat threshold and the outdoor heat exchanger temperature difference is lower than the preset temperature difference threshold, it is determined that the running time of the compressor, the exhaust superheat, the refrigerant pressure and the outdoor heat exchanger temperature difference meet the fluorine deficiency protection conditions. In other words, when all the above conditions are met, it is determined that the refrigerant circulation system lacks fluorine and fluorine deficiency protection is required. The refrigerant leakage is judged based on multiple parameters such as the refrigerant pressure, the exhaust superheat and the outdoor heat exchanger temperature difference. The refrigerant leakage judgment is more accurate and can avoid misjudgment or missed judgment.

[0065] In some embodiments, the controller is further configured to: before the fluorine deficiency protection condition is determined, obtain a pressure correction coefficient based on the outdoor ambient temperature, and correct the refrigerant pressure based on the pressure correction coefficient, and / or obtain a superheat correction coefficient based on the outdoor ambient temperature, and correct the exhaust superheat based on the superheat correction coefficient.

[0066] Specifically, the compressor will have different refrigerant pressures when running at different frequencies. The refrigerant pressures corresponding to different frequencies at different temperatures are different, so it is necessary to obtain the pressure correction coefficient, such as Figure 6 The diagram shows the relationship between refrigerant pressure and frequency. Figure 7 The figure shows the correction coefficient diagram of the effect of outdoor ambient temperature on refrigerant pressure. At different temperatures, the pressure correction coefficient is obtained, and the refrigerant pressure of different frequencies is corrected according to the pressure correction coefficient to make the detected refrigerant pressure more accurate. Figure 8The figure shows a frequency and exhaust superheat curve. The exhaust superheat of the compressor is different at different frequencies, and the exhaust superheat corresponding to the frequency is different at different temperatures. Therefore, it is necessary to obtain the superheat correction coefficient, such as Fig. 9 The figure shows the correction coefficient diagram of the effect of outdoor ambient temperature on superheat. At different temperatures, the heat correction coefficient is obtained, and the exhaust superheat of different frequencies is corrected according to the superheat correction coefficient, so that the calculated exhaust superheat is more accurate and the accuracy of refrigerant leakage judgment is improved.

[0067] In some embodiments, the controller is further configured to: record the duration of the compressor operating time, exhaust superheat, refrigerant pressure and outdoor heat exchanger temperature difference to meet the fluorine deficiency protection conditions; when the duration reaches a second preset time threshold, record it as a fluorine deficiency protection trigger instruction; when a preset number of fluorine deficiency protection trigger instructions are obtained within a preset time period, execute the fluorine deficiency protection strategy.

[0068] Specifically, after the running time of the compressor, the exhaust superheat, the refrigerant pressure and the temperature difference of the outdoor heat exchanger meet the fluorine deficiency protection conditions, the duration of the fluorine deficiency protection conditions is recorded; when the duration of the fluorine deficiency protection conditions reaches a second preset time threshold, it is recorded as a fluorine deficiency protection trigger instruction. The second time threshold can be understood as the duration after the fluorine deficiency protection conditions are met. For example, the second time threshold may be 3 minutes. When the duration of the fluorine deficiency protection condition reaches 3 minutes, a fluorine deficiency protection trigger instruction is recorded; when a preset number of fluorine deficiency protection trigger instructions are obtained within a preset time period, the fluorine deficiency protection strategy is executed, and the air conditioner stops working. For example, the preset time period may be 30 minutes, and the preset number of fluorine deficiency protection trigger instructions may be 2 times. That is, when the fluorine deficiency protection trigger instruction is detected twice consecutively within 30 minutes, the fluorine deficiency protection strategy is executed, and the air conditioner stops working to avoid misjudgment.

[0069] For example, the indoor unit of the air conditioner can send a 24V AC cooling start signal and a heating start signal to the outdoor unit. When the outdoor unit receives the 24V cooling start signal, the compressor frequency is controlled by controlling the system pressure value. Under the rated cooling conditions (outdoor dry bulb temperature 35℃, outdoor wet bulb temperature 23.9℃, indoor dry bulb temperature 26.7℃, indoor wet bulb temperature 19.4℃), there are corresponding refrigerant pressures and exhaust superheat when running at different frequencies. The calculation formula for exhaust superheat is: DSH=Td-Tcoil; Where DSH is the exhaust superheat, Td is the exhaust temperature of the compressor, and Tc is the saturation temperature corresponding to the condensing temperature.

[0070] Because the ambient temperature will affect the pressure and exhaust temperature, the condensing pressure and exhaust superheat value will be corrected according to the different ambient temperatures during actual operation. The compressor frequency, pressure, and exhaust superheat values ​​are preset in the controller component. During actual installation and operation, the operating parameters are compared with the preset parameters. When the amount of refrigerant is small, the system pressure will decrease and the exhaust superheat will increase. Combined with the system characteristics under the fluorine deficiency state, the fluorine deficiency entry conditions are: the compressor runs for 10 minutes; the exhaust superheat DSH ≥ 45°C; the outdoor ambient temperature-the outdoor heat exchanger temperature < 2°C; the pressure detected by the pressure sensor is lower than 30% of the rated value; when the above conditions are met at the same time and last for 3 minutes, a fluorine deficiency is recorded (the time of 3 minutes is reset to zero); if it occurs twice within 30 minutes, the fluorine deficiency fault is reported and the machine is shut down. If it occurs less than 2 times, the protection times are cleared and counted again. When the fluorine deficiency fault lasts for 2 times, the machine will be shut down for protection. Other protection codes are prompted. After the fluorine deficiency shutdown protection appears, it will not be restarted. It will be re-determined after power failure. The machine will exit the fluorine deficiency protection after receiving the power on / off signal or powering on again.

[0071] refer to Fig.10 As shown, the specific process of fluorine deficiency protection includes the following steps.

[0072] Step S4, start.

[0073] Step S5, after the compressor runs for 10 minutes, the refrigerant pressure is obtained.

[0074] Step S6, determining whether the refrigerant pressure is lower than 30% of the normal value, if so, executing step S7, if not, executing step S8.

[0075] Step S7, judging whether the exhaust gas superheat and the outdoor heat exchanger temperature difference meet the fluorine deficiency protection condition, if so, executing step S9, if not, executing step S8.

[0076] Step S8: The compressor operates at normal frequency.

[0077] Step S9, determining whether two fluorine deficiency protection trigger instructions are obtained within 30 minutes, if so, executing step S10, if not, executing step S8.

[0078] Step S10, reporting a fluorine deficiency fault, and the compressor stops working.

[0079] The entire fluorine deficiency protection control process is mainly judged by the refrigerant pressure, and the auxiliary exhaust gas superheat, outdoor heat exchanger temperature difference and other conditions are comprehensively and accurately judged whether the refrigerant circulation system is short of refrigerant, so as to effectively protect the refrigerant circulation system.

[0080] In some embodiments, the controller is further configured to control the compressor to operate at normal frequency when the refrigerant pressure is higher than a preset pressure threshold, the exhaust superheat does not exceed a preset superheat threshold, or the outdoor heat exchanger temperature difference is not lower than a preset temperature difference threshold.

[0081] Specifically, in order to make the judgment of refrigerant leakage more accurate and avoid misjudgment or missed judgment, when the compressor is running stably, the refrigerant pressure, compressor exhaust superheat and outdoor heat exchanger temperature difference conditions are combined to accurately judge whether the refrigeration system lacks refrigerant. If all the above conditions are met, it is determined that the compressor is short of fluorine and fluorine deficiency protection is performed; as long as the refrigerant pressure is higher than the preset pressure threshold or the exhaust superheat does not exceed the preset superheat threshold or the outdoor heat exchanger temperature difference is not lower than the preset temperature difference threshold, any one of the three conditions is met, the compressor will run at a normal frequency.

[0082] In some embodiments, when executing the fluorine deficiency protection strategy, the controller is configured to: control the compressor to stop.

[0083] Specifically, when the controller determines that the refrigerant is insufficient through comprehensive conditions such as refrigerant pressure, exhaust superheat, and outdoor heat exchanger temperature difference, the fluorine deficiency protection strategy is triggered. The controller controls the compressor to shut down to prevent the refrigerant circulation system from continuing to operate in a fluorine deficiency state, thereby avoiding potential damage to the air conditioner.

[0084] In some embodiments, when executing the fluorine deficiency protection strategy, the controller is further configured to: provide a fluorine deficiency fault prompt.

[0085] Specifically, when the controller executes the fluorine deficiency protection strategy, in addition to controlling the compressor to shut down to prevent system damage, it is also configured to issue a fluorine deficiency fault prompt to inform the user that the system is currently in a fluorine deficiency state and needs to take corresponding measures; the fluorine deficiency fault prompt can be prompted through sound and light alarms and display screens. The fluorine deficiency fault prompt can be sent remotely to the after-sales center at the same time, so that after-sales personnel can contact the user as soon as possible to resolve the fault.

[0086] For example, the operation monitoring curve of the air conditioner is as follows: Fig.11 As shown in the figure, it can be seen that when the refrigerant volume of the air conditioner is less than 30% of the normal volume, the fluorine deficiency protection strategy is executed and a fault is prompted. During the compressor operation time, the frequency curve of the compressor, the pressure value obtained by the pressure sensor, the exhaust superheat, the outdoor heat exchanger temperature difference, and the air conditioner refrigerant volume are plotted in real time. Fig.11 In the figure, when recording the fluorine deficiency protection, it can be seen that the offset of each curve is large.

[0087] In some embodiments, the controller is further configured to: exit the fluorine deficiency protection strategy when receiving an on / off signal of the air conditioner, or exit the fluorine deficiency protection strategy after the air conditioner is powered on again.

[0088] Specifically, when the air conditioner receives a power-on signal, it means that the air conditioner needs to be restarted. At this time, the fluorine deficiency protection strategy is exited, and the fluorine deficiency is re-determined when the air conditioner is turned on next time. When the air conditioner receives a shutdown signal, the air conditioner stops running, the compressor also stops running, and the fluorine deficiency protection strategy is exited. After the air conditioner is powered on again after a power outage, the controller will perform a series of initialization steps to ensure that the air conditioner can start and run correctly. At this time, the fluorine deficiency protection strategy is exited, and after the controller is initialized, it is re-determined whether there is a lack of fluorine.

[0089] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0090] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An air conditioner, characterized in that: include: A refrigerant circulation system, the refrigerant circulation system comprising a compressor, a throttling device, a switching device, an indoor heat exchanger and an outdoor heat exchanger, the switching device being respectively connected to the outdoor heat exchanger, the indoor heat exchanger, the exhaust port of the compressor and the return port of the compressor; A pressure sensor, the pressure sensor being disposed on a connecting pipeline between the switching device and the indoor heat exchanger and used for detecting the refrigerant pressure in the refrigerant circulation system; A first temperature sensor is disposed at the exhaust port of the compressor and is used to detect the exhaust temperature; A second temperature sensor is provided on the outdoor heat exchanger and is used to detect the temperature of the outdoor heat exchanger; A controller, the controller being connected to the pressure sensor, the first temperature sensor and the second temperature sensor, the controller being configured as follows: Obtaining the operating time of the compressor; Obtaining exhaust gas superheat according to the exhaust gas temperature, and obtaining an outdoor heat exchanger temperature difference according to the outdoor heat exchanger temperature; When the running time of the compressor, the exhaust gas superheat, the refrigerant pressure and the temperature difference of the outdoor heat exchanger meet the fluorine deficiency protection conditions, the fluorine deficiency protection strategy is executed.

2. The air conditioner according to claim 1, characterized in that: The fluorine-deficient protection conditions include: The running time of the compressor reaches a first preset time threshold; The exhaust gas superheat exceeds a preset superheat threshold; The outdoor heat exchanger temperature difference is lower than a preset temperature difference threshold; The refrigerant pressure is lower than a preset pressure threshold.

3. The air conditioner according to claim 1 or 2, characterized in that: The outdoor heat exchanger temperature difference is the temperature difference between the outdoor ambient temperature and the outdoor heat exchanger temperature.

4. The air conditioner according to claim 2, characterized in that: The controller is configured to: After the operation time of the compressor reaches the first preset time threshold, judging the refrigerant pressure; After determining that the refrigerant pressure is lower than the preset pressure threshold, judging the exhaust gas superheat and the outdoor heat exchanger temperature difference respectively; When the exhaust superheat exceeds the preset superheat threshold and the outdoor heat exchanger temperature difference is lower than the preset temperature difference threshold, it is determined that the compressor operation time, the exhaust superheat, the refrigerant pressure and the outdoor heat exchanger temperature difference meet the fluorine deficiency protection condition.

5. The air conditioner according to claim 4, characterized in that: The controller is also configured to: Before the fluorine deficiency protection condition is determined, a pressure correction coefficient is obtained according to the outdoor ambient temperature, and the refrigerant pressure is corrected according to the pressure correction coefficient, and / or a superheat correction coefficient is obtained according to the outdoor ambient temperature, and the exhaust superheat is corrected according to the superheat correction coefficient.

6. The air conditioner according to claim 4, characterized in that: The controller is also configured to: Recording the duration of the compressor operation time, the exhaust gas superheat, the refrigerant pressure and the temperature difference of the outdoor heat exchanger satisfying the fluorine deficiency protection condition; When the duration reaches a second preset time threshold, it is recorded as a fluorine deficiency protection trigger instruction; When a preset number of fluorine deficiency protection trigger instructions are obtained within a preset time period, the fluorine deficiency protection strategy is executed.

7. The air conditioner according to claim 4, characterized in that: The controller is also configured to: When the refrigerant pressure is higher than the preset pressure threshold, or the exhaust superheat does not exceed the preset superheat threshold, or the outdoor heat exchanger temperature difference is not lower than the preset temperature difference threshold, the compressor is controlled to operate at a normal frequency.

8. The air conditioner according to claim 1, characterized in that: When executing the fluorine deficiency protection strategy, the controller is configured to: control the compressor to stop.

9. The air conditioner according to claim 8, characterized in that: When executing the fluorine deficiency protection strategy, the controller is further configured to: provide a fluorine deficiency fault prompt.

10. The air conditioner according to any one of claims 1, 2, 4-9, characterized in that: The controller is further configured to: exit the fluorine deficiency protection strategy when receiving a power on / off signal of the air conditioner, or exit the fluorine deficiency protection strategy after the air conditioner is powered on again.

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