Heating high temperature protection and heating refrigerant shortage protection method, device and air conditioning system

Abstract

The present invention provides a method, device, and air conditioning system for protecting against high temperature and refrigerant shortage in heating. The method comprises the following steps: in heating mode, turning on the outdoor fan and detecting in real time the outdoor ambient temperature, the exhaust temperature of the compressor, the fan current of the outdoor fan, and the operating time of the outdoor fan; when the operating time exceeds a first preset time, comparing whether the sum of the exhaust temperature and the compensation temperature is greater than the first preset temperature and whether the fan current is greater than a preset current value; the compensation temperature is associated with the outdoor ambient temperature; if the conditions are met, the outdoor fan is controlled to stop running and the indoor unit operates normally; after the outdoor fan stops running, determining whether the sum of the exhaust temperature and the compensation temperature is greater than a second preset temperature and lasts for a second time; if the conditions are met, the compressor is controlled to stop and a fault is reported. The present invention can prevent the air conditioner from mistakenly entering the high temperature protection mode due to refrigerant shortage, thereby improving the stability and reliability of the air conditioning system.

Description

Technical Field

[0001] The present invention relates to the field of air conditioning, and in particular to a method and device for protecting heating from high temperature and lack of refrigerant, and an air conditioning system. Background Art

[0002] When the air conditioner is heating in a high temperature environment, due to the high temperature of the indoor heat exchanger, in order to avoid damage to the compressor caused by excessive pressure, it is necessary to intermittently stop the outdoor unit fan and actively perform heating unloading.

[0003] Existing methods for preventing high temperatures during heating include: collecting the indoor heat exchanger temperature and comparing it to preset parameters. If the indoor heat exchanger temperature exceeds the preset parameters, high-temperature protection is implemented and the outdoor fan is stopped. The indoor heat exchanger temperature is controlled by the air conditioner's indoor unit mainboard, so communication between the indoor and outdoor units is required to control the start and stop of the outdoor unit's compressor. This high-temperature protection control is impossible for some fixed-frequency air conditioning systems where the indoor and outdoor units do not communicate. In addition, if the indoor heat exchanger temperature is the primary or sole control factor, the high-temperature protection control will fail if the indoor heat exchanger temperature is abnormal, the indoor heat exchanger temperature takes too long to fall, or the protective temperature parameters are not designed properly, shortening the compressor's service life. Summary of the Invention

[0004] To address the above issues, the present invention provides a method, device, and air conditioning system for protecting against high-temperature heating and refrigerant shortages. These methods, without requiring communication between the indoor and outdoor units, replace the indoor unit temperature to determine whether to enter high-temperature protection mode. The accuracy of this judgment ensures that the air conditioning system enters high-temperature protection mode promptly, improving the reliability of air conditioning operation. Furthermore, the method can eliminate the possibility of excessively high exhaust temperatures caused by refrigerant shortages, preventing the system from mistakenly entering high-temperature protection mode due to refrigerant shortages, thereby improving the stability and reliability of the air conditioning system's operation.

[0005] The present invention provides a method for protecting an air-conditioning system from high temperature and lack of refrigerant during heating. The air-conditioning system includes an indoor unit and an outdoor unit. The outdoor unit includes at least a compressor and an outdoor fan. The protection method includes the following steps:

[0006] Testing steps: In heating mode, turn on the outdoor fan and detect the outdoor ambient temperature, the exhaust temperature of the compressor, the fan current of the outdoor fan, and the running time of the outdoor fan in real time;

[0007] High temperature prevention judgment step: when the operating time is longer than a first preset time, comparing whether the sum of the exhaust temperature and the compensation temperature is greater than the first preset temperature and whether the fan current is greater than the current preset value; wherein the compensation temperature is associated with the outdoor ambient temperature;

[0008] Anti-high temperature protection entry steps: when the sum of the exhaust temperature and the compensation temperature is greater than the first preset temperature and the fan current is greater than the current preset value, the outdoor fan is controlled to stop running and the indoor unit operates normally;

[0009] Refrigerant shortage judgment step: after the external fan stops running, judge whether the sum of the exhaust temperature and the compensation temperature is greater than the second preset temperature and lasts for a second time period;

[0010] Refrigerant shortage protection entry steps: When the sum of the exhaust temperature and the compensation temperature is greater than the second preset temperature and lasts for the second time period, the compressor is controlled to stop and a fault is reported.

[0011] According to this technical solution, corresponding compensation temperatures are preset to compensate the exhaust temperature according to the different outdoor ambient temperatures, so that the compensated exhaust temperature can reflect the temperature status of the indoor unit. In this way, the indoor unit temperature can be used to determine whether to enter the high temperature protection mode without the need for communication between the indoor and outdoor units, and the accuracy of the high temperature protection judgment can be guaranteed, allowing the air conditioning system to enter the high temperature protection mode in a timely manner, thereby improving the reliability of air conditioning operation. In addition, based on the comparison result of the compensated exhaust temperature with the preset temperature, it is determined whether there is a lack of refrigerant, and the high exhaust temperature caused by the lack of refrigerant is eliminated. This can avoid the erroneous operation of entering the high temperature protection mode based solely on the exhaust temperature judgment, improve the accuracy of entering the high temperature protection mode, and promptly report the fault when there is a lack of refrigerant, thereby improving the stability and reliability of the air conditioning system operation.

[0012] In an optional technical solution of the present invention, the air-conditioning system is a non-communication fixed-frequency air-conditioning system with indoor and outdoor units.

[0013] In an optional technical solution of the present invention, in the high temperature protection judgment step, associating the compensation temperature with the outdoor ambient temperature includes:

[0014] When the outdoor ambient temperature is greater than the first temperature threshold, the compensation temperature is the first compensation temperature;

[0015] The outdoor ambient temperature is greater than the second temperature threshold and less than or equal to the first temperature threshold, and the compensation temperature is the second compensation temperature;

[0016] The outdoor ambient temperature is less than or equal to the second temperature threshold, the compensation temperature is the third compensation temperature, and the first temperature threshold is greater than the second temperature threshold.

[0017] According to this technical solution, by setting multiple temperature intervals and multiple compensation temperatures, it is beneficial to improve the accuracy of high temperature protection and refrigerant shortage judgment.

[0018] In an optional technical solution of the present invention, in the refrigerant shortage judgment step, the value range of the second preset temperature is 90-110°C.

[0019] According to this technical solution, after the external fan stops running in the high temperature protection mode, under normal circumstances, the exhaust temperature will decrease due to poor evaporation, thereby achieving the purpose of high temperature protection. However, when the system is seriously short of refrigerant, the exhaust temperature is not sufficiently cooled by the refrigerant circulation, and the exhaust temperature will continue to rise due to the heat of the compressor. Therefore, whether the external fan is running has little effect on the exhaust temperature. When the exhaust temperature is too high, it can be determined that the exhaust temperature has increased due to lack of refrigerant.

[0020] In an optional technical solution of the present invention, the outdoor unit further includes an outdoor heat exchanger, and the protection method further includes:

[0021] The external fan start-up control step is to determine whether the external fan meets the external fan start-up conditions; if so, the external fan is started; if not, the process returns to the high temperature protection entry step; wherein, the external fan start-up conditions include:

[0022] The shutdown time of the external fan is longer than the third preset time;

[0023] The sum of the exhaust temperature and the compensation temperature is less than a third preset temperature, and the third preset temperature is less than the first preset temperature;

[0024] Or the difference between the outdoor ambient temperature and the outlet temperature of the outdoor heat exchanger is greater than the first temperature difference threshold.

[0025] According to this technical solution, when the outdoor fan is shut down in high-temperature protection mode, this typically results in a decrease in the outdoor unit's evaporation efficiency and a drop in the exhaust temperature, thereby achieving the purpose of high-temperature protection. When the shutdown duration exceeds a third preset duration, the outdoor fan is forcibly started. This can prevent the air conditioning system from being in high-temperature protection mode for a long time due to a slow drop in exhaust temperature under high-temperature conditions or due to thermal inertia of the outdoor heat exchanger temperature or a dirty or clogged outdoor heat exchanger. This can cause the outdoor unit's evaporation efficiency to deteriorate and freeze, requiring the air conditioner to perform frosting and defrosting operations, thereby improving the user experience. Alternatively, when the sum of the exhaust temperature and the compensation temperature is less than the third preset temperature, i.e., when the exhaust temperature drops significantly, the high-temperature protection mode is exited, allowing the outdoor fan to operate normally to ensure the outdoor unit's evaporation efficiency. Alternatively, when the outlet temperature of the outdoor heat exchanger drops below the outdoor ambient temperature to a certain extent, indicating that the evaporation efficiency has deteriorated, the exhaust temperature will decrease, and high-temperature protection can be achieved. Furthermore, when the difference between the outdoor ambient temperature and the outlet temperature of the outdoor heat exchanger exceeds a first temperature difference threshold, the outdoor fan is promptly started to improve the evaporation efficiency and prevent frost on the outdoor unit. You can choose any condition to exit the high temperature protection according to the actual situation. It is highly flexible and conducive to the reliable operation of the air-conditioning system and improves the user experience.

[0026] In an optional technical solution of the present invention, the value range of the third preset time length is 3-10 minutes.

[0027] According to this technical solution, by selecting an appropriate duration, it is possible to prevent the high temperature protection mode from running for a long time, which may cause the evaporation effect to deteriorate and affect the heating effect.

[0028] In an optional technical solution of the present invention, the third preset temperature ranges from 70°C to 90°C.

[0029] According to this technical solution, by selecting a suitable exhaust temperature range, the high-temperature protection mode can be promptly exited when the exhaust temperature drops to a certain level, thereby ensuring the reliable operation of the air-conditioning system and improving the user experience.

[0030] In an optional technical solution of the present invention, the value range of the first temperature difference threshold is 10-40°C.

[0031] According to this technical solution, selecting an appropriate first temperature difference threshold can avoid the outdoor heat exchanger outlet temperature being too high, resulting in frequent entry into high temperature protection, or the outdoor heat exchanger outlet temperature being too low, resulting in frost on the outdoor heat exchanger, thereby improving the service life of the air conditioner and user experience.

[0032] Another aspect of the present invention provides a device for protecting an air-conditioning system from high temperature and lack of refrigerant during heating, comprising:

[0033] The detection module is used to detect the outdoor ambient temperature, the exhaust temperature of the compressor, the fan current of the outdoor fan, and the operating time of the outdoor fan in real time under the condition that the outdoor fan is turned on in the heating mode;

[0034] a high temperature prevention judgment module, configured to compare whether the sum of the exhaust temperature and the compensation temperature is greater than the first preset temperature and whether the fan current is greater than the preset current value when the operating time is greater than a first preset time; wherein the compensation temperature is associated with the outdoor ambient temperature;

[0035] The high temperature protection entry module is used to control the outdoor fan to stop running and the indoor unit to operate normally when the sum of the exhaust temperature and the compensation temperature is greater than the first preset temperature and the fan current is greater than the current preset value;

[0036] A refrigerant shortage judgment module is used to judge whether the sum of the exhaust temperature and the compensation temperature is greater than a second preset temperature and lasts for a second time period after the external fan stops running;

[0037] The refrigerant shortage protection entry module is used to control the compressor to stop and report a fault when the sum of the exhaust temperature and the compensation temperature is greater than the second preset temperature and lasts for a second time.

[0038] Another aspect of the present invention provides an air-conditioning system, comprising the above-mentioned protection device for preventing high temperature during heating and lack of refrigerant during heating of the air-conditioning system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1Schematic diagram of the structure of the air-conditioning system in an embodiment of the present invention.

[0040] Figure 2 Schematic diagram of a flow chart of a method for protecting an air-conditioning system from high temperature and lack of refrigerant during heating according to an embodiment of the present invention.

[0041] Figure 3 Schematic diagram of the modular structure of the protection device for preventing high temperature and lack of refrigerant during heating of the air-conditioning system in an embodiment of the present invention.

[0042] Reference numerals:

[0043] Compressor 11; first temperature detector 111; four-way valve 12; outdoor heat exchanger 13; second temperature detector 131; first throttling element 14; liquid storage tank 15; second throttling element 16; indoor heat exchanger 17; gas-liquid separator 18; one-way valve 2; pressure sensor 3; low-pressure pressure switch 4; high-pressure pressure switch 5; detection module 61; high-temperature protection judgment module 62; high-temperature protection entry module 63; refrigerant shortage judgment module 64; refrigerant shortage protection entry module 65; outdoor fan start-up control module 66. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0045] like Figure 1As shown, an embodiment of the present invention provides an air conditioning system, comprising a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, an outdoor fan (not shown), a first throttle element 14, a liquid storage tank 15, a second throttle element 16, an indoor heat exchanger 17, and a gas-liquid separator 18, which are sequentially connected to form a refrigerant circulation flow path. Furthermore, the system comprises a first temperature detector 111 (a temperature sensor package provided on the exhaust pipe) for detecting the exhaust temperature of the compressor, and a second temperature detector 131 for detecting the outdoor ambient temperature. Furthermore, a one-way valve 2 is provided in parallel at both ends of the second throttle element 16, which controls the one-way flow of refrigerant from the liquid storage tank 15 to the indoor heat exchanger 18. A pressure sensor 3 is provided on the pipeline between the indoor heat exchanger 18 and the four-way valve 12. A low-pressure switch 4 is provided between the four-way valve 12 and the gas-liquid separator 18. A high-pressure switch 5 is provided between the compressor 11 and the four-way valve 12. Among them, the role of the liquid storage tank 15 is similar to that of the gas-liquid separator 18. The gaseous refrigerant produced by the separation enters the compressor 11 through a branch pipeline to replenish the refrigerant, and the liquid refrigerant produced by the separation enters the refrigerant main line. The high-pressure pressure switch 5 and the low-pressure pressure switch 4 are used to monitor the pressure of the refrigerant in the air-conditioning pipeline and feedback it to the air-conditioning controller (not shown in the figure). When the refrigerant pressure is too low, the low-pressure pressure switch 4 is disconnected. After receiving this signal, the controller knows that the refrigerant in the system is insufficient and controls the compressor 11 to stop working. When the refrigerant pressure is too high, the high-pressure pressure switch 5 is disconnected. After receiving this signal, the controller controls the compressor 11 to stop working to prevent the pressure from being too high and causing a pipe burst. Preferably, the air-conditioning system in this embodiment is a fixed-frequency air-conditioning system with no communication between the internal and external units, and the compressor 11 is a fixed-frequency compressor. It should be noted that although the embodiment of the present invention shows the above-mentioned air-conditioning system structure, it should not constitute a limitation on the air-conditioning system. Air-conditioning systems with other structural forms are also applicable to the protection methods for high temperature protection and refrigerant shortage in heating provided below.

[0046] like Figure 2 As shown, the present invention provides a method for protecting an air-conditioning system from high temperature and lack of refrigerant during heating, comprising the following steps:

[0047] Testing steps: In heating mode, turn on the outdoor fan and detect the outdoor ambient temperature, the exhaust temperature of the compressor, the fan current of the outdoor fan, and the running time of the outdoor fan in real time;

[0048] High temperature prevention judgment step: when the operating time is greater than a first preset time (e.g., the operating time is greater than 3 minutes, to avoid situations where the exhaust temperature quickly reaches the set value (referring to the first preset temperature) for stopping the outdoor fan after a short period of operation, and the outdoor fan is stopped again, and the accumulated time of stopping the outdoor fan is too long, the outdoor heat exchanger lacks effective heat exchange and causes frost), compare whether the sum of the exhaust temperature and the compensation temperature is greater than the first preset temperature and whether the fan current is greater than the current preset value; wherein the compensation temperature is associated with the outdoor ambient temperature;

[0049] Anti-high temperature protection entry steps: when the sum of the exhaust temperature and the compensation temperature is greater than the first preset temperature and the fan current is greater than the current preset value, the outdoor fan is controlled to stop running and the indoor unit operates normally;

[0050] Refrigerant shortage judgment step: after the external fan stops running, judge whether the exhaust temperature is greater than the second preset temperature and lasts for a second time period (e.g., 2 minutes);

[0051] Refrigerant shortage protection entry steps: When the exhaust temperature is greater than the second preset temperature and lasts for the second time, the compressor is controlled to stop and a fault is reported.

[0052] Through the above method, corresponding compensation temperatures are preset to compensate the exhaust temperature according to the outdoor ambient temperature, so that the compensated exhaust temperature can reflect the temperature status of the indoor unit. In this way, the indoor unit temperature can be used to determine whether to enter the high temperature protection mode without the need for communication between the indoor and outdoor units. The accuracy of the high temperature protection judgment can be guaranteed, allowing the air conditioning system to enter the high temperature protection mode in a timely manner, improving the reliability of air conditioning operation and saving the cost of communication lines between the indoor and outdoor units. The temperature detector is a component of the system itself, so there is no additional cost. In addition, based on the comparison result of the compensated exhaust temperature with the preset temperature, it is possible to determine whether there is a refrigerant shortage. This can eliminate the possibility of excessive exhaust temperature caused by refrigerant shortage, avoid mistakenly entering the high temperature protection mode due to refrigerant shortage, and promptly report the fault when there is a refrigerant shortage, thereby improving the stability of the air conditioning system operation.

[0053] In a preferred embodiment of the present invention, in the high temperature prevention judgment step, associating the compensation temperature with the outdoor ambient temperature includes:

[0054] When the outdoor ambient temperature is greater than the first temperature threshold (such as 24°C), the compensation temperature is the first compensation temperature (such as 0°C);

[0055] If the outdoor ambient temperature is greater than the second temperature threshold and less than or equal to the first temperature threshold, the compensation temperature is the second compensation temperature (e.g., 4°C);

[0056] The outdoor ambient temperature is less than or equal to the second temperature threshold (eg, 14° C.), the compensation temperature is the third compensation temperature (eg, 7° C.), and the first temperature threshold is greater than the second temperature threshold.

[0057] By setting multiple temperature ranges and multiple compensation temperatures in the above manner, the accuracy of high temperature protection and refrigerant shortage judgment can be improved. Technicians can adjust the temperature threshold and compensation temperature value according to actual conditions. Preferably, the first compensation temperature range is -5 to 5°C, the second compensation temperature range is -5 to 5°C, and the third compensation temperature range is -5 to 5°C.

[0058] In a preferred embodiment of the present invention, in the high temperature protection judgment step, the value range of the first preset temperature is 70-100°C, preferably 82°C (the first preset temperature is the exhaust temperature corresponding to the indoor heat exchanger temperature of 55°C. Depending on the type of compressor, the exhaust temperature corresponding to the indoor heat exchanger temperature of 55°C may be different. Technicians can adaptively adjust the first preset temperature).

[0059] In a preferred embodiment of the present invention, in the refrigerant shortage judgment step, the value range of the second preset temperature is 90-110°C; preferably 105°C. In the above manner, after the external fan stops running in the high temperature protection mode, under normal circumstances, the exhaust temperature will decrease due to poor evaporation, thereby achieving the purpose of high temperature protection. However, in the case of a serious lack of refrigerant in the system, the exhaust temperature does not have sufficient refrigerant circulation cooling, and the exhaust temperature will continue to rise due to the heat of the compressor. Therefore, whether the external fan is running has little effect on the exhaust temperature. When the exhaust temperature is too high, it can be determined that the exhaust temperature has increased due to lack of refrigerant. Furthermore, the second preset temperature is lower than the normal exhaust protection temperature of the compressor (generally 115°C), so that the compressor 11 can be protected in time when there is a lack of refrigerant, thereby increasing the service life of the compressor 11.

[0060] In a preferred embodiment of the present invention, the protection method further comprises:

[0061] The external fan start-up control step is to determine whether the external fan meets the external fan start-up conditions; if so, the external fan is started; if not, the process returns to the high temperature protection entry step; wherein, the external fan start-up conditions include:

[0062] The shutdown time of the external fan is longer than the third preset time;

[0063] The sum of the exhaust temperature and the compensation temperature is less than a third preset temperature, and the third preset temperature is less than the first preset temperature;

[0064] Or the difference between the outdoor ambient temperature and the outlet temperature of the outdoor heat exchanger is greater than the first temperature difference threshold.

[0065] Through the above-mentioned method, when the outdoor fan is shut down in the high temperature protection mode, the outdoor unit's evaporation effect will usually deteriorate and the exhaust temperature will drop, thereby achieving the purpose of high temperature protection. When the shutdown time is longer than the third preset time, the outdoor fan is forced to start. This can avoid the air conditioning system being in the high temperature protection mode for a long time due to the slow exhaust temperature drop rate under high temperature conditions or due to the thermal inertia of the outdoor heat exchanger temperature or the outdoor heat exchanger being dirty or blocked, causing the air conditioning system to be in the high temperature protection mode for a long time, the outdoor unit's evaporation effect to deteriorate, and the air conditioning to perform frosting and defrosting actions. Alternatively, when the sum of the exhaust temperature and the compensation temperature is less than the third preset temperature, that is, when the exhaust temperature drops significantly, the high temperature protection mode is exited, allowing the outdoor fan to operate normally to ensure the evaporation effect of the outdoor unit; or when the outlet temperature of the outdoor heat exchanger is lower than the outdoor ambient temperature to a certain extent, it means that the evaporation effect has deteriorated and the exhaust temperature will drop, thus achieving high temperature protection. Furthermore, when the difference between the outdoor ambient temperature and the outlet temperature of the outdoor heat exchanger is greater than the first temperature difference threshold, the outdoor fan is started in time to improve the evaporation effect and prevent frost on the outdoor unit. You can choose any condition to exit the high temperature protection according to the actual situation. It is highly flexible and conducive to the reliable operation of the air-conditioning system and improves the user experience.

[0066] In a preferred embodiment of the present invention, the third preset duration is in the range of 3-10 minutes, preferably 6 minutes. Selecting an appropriate duration can prevent prolonged operation of the high temperature protection mode, which can deteriorate the evaporation effect and affect the heating effect.

[0067] In a preferred embodiment of the present invention, the third preset temperature is in the range of 70-90°C, preferably 76°C (the third preset temperature is the exhaust temperature corresponding to an indoor heat exchanger temperature of 48°C. Depending on the type of compressor, the exhaust temperature corresponding to an indoor heat exchanger temperature of 48°C may be different, and technicians can adaptively adjust the third preset temperature).

[0068] Selecting an appropriate exhaust temperature range can promptly exit the high-temperature protection mode when the exhaust temperature drops to a certain level, ensuring the reliable operation of the air-conditioning system and improving the user experience.

[0069] In a preferred embodiment of the present invention, the first temperature difference threshold value ranges from 10 to 40°C, preferably 30°C.

[0070] By selecting an appropriate first temperature difference threshold in the above manner, it is possible to avoid frequent high temperature protection due to excessively high outlet temperature of the outdoor heat exchanger or frosting of the outdoor heat exchanger due to excessively low outlet temperature of the outdoor heat exchanger, thereby improving the service life of the air conditioner and user experience.

[0071] It should be noted that, although this embodiment describes the application of the protection method to a fixed-frequency machine system under non-communication conditions, it is conceivable that the method can also be applied to a fixed-frequency machine system.

[0072] like Figure 3 As shown, another aspect of the present invention provides a device for protecting an air-conditioning system from high temperature and lack of refrigerant during heating, comprising:

[0073] The detection module 61 is used to detect the outdoor ambient temperature, the exhaust temperature of the compressor 11, the fan current of the outdoor fan, and the operating time of the outdoor fan in real time under the condition that the outdoor fan is turned on in the heating mode;

[0074] The high temperature prevention judgment module 62 is used to compare whether the sum of the exhaust temperature and the compensation temperature is greater than the first preset temperature and whether the fan current is greater than the preset current value when the operating time is greater than the first preset time; wherein the compensation temperature is associated with the outdoor ambient temperature;

[0075] The high temperature protection entry module 63 is used to control the outdoor fan to stop running and the indoor unit (indoor heat exchanger 17) to operate normally when the sum of the exhaust temperature and the compensation temperature is greater than the first preset temperature and the fan current is greater than the current preset value;

[0076] A refrigerant shortage determination module 64 is configured to determine whether the exhaust temperature is greater than a second preset temperature and lasts for a second period of time after the external fan stops running;

[0077] The refrigerant shortage protection entry module 65 is used to control the compressor to stop and report a fault when the exhaust temperature is greater than a second preset temperature and lasts for a second period of time.

[0078] Specifically, in this embodiment, the detection module may include temperature detection modules such as a temperature sensing package and a temperature sensor, an ammeter for detecting the fan current, and a timer for detecting the shutdown time. The high temperature protection judgment module and the refrigerant shortage judgment module can also be integrated into the controller of the air conditioner, and the controller is used to judge whether the air conditioner has entered the high temperature protection and refrigerant shortage protection according to the above-mentioned operation logic. The high temperature protection entry module and the refrigerant shortage protection entry module can be integrated into the controller of the air conditioner, and the controller is used to control the air conditioner to enter the refrigerant shortage protection according to the comparison result of the exhaust temperature and the second preset temperature, and to control the air conditioner to enter the high temperature protection according to the comparison result of the sum of the exhaust temperature and the compensation temperature with the first preset temperature, the fan current and the current preset value. Specifically, the controller can be an integrated circuit chip with signal processing capabilities. The above-mentioned controller can be a general-purpose processor, including a central processing unit (CPU), or a single-chip microcomputer, a microcontroller unit (MCU), a complex programmable logic device (CPLD), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), an embedded ARM and other chips. The controller can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present invention.

[0079] In a preferred embodiment of the present invention, the protection device further includes an external fan start-up control module 66, which determines whether the external fan meets the external fan start-up conditions; if so, the external fan is started; if not, the high temperature protection entry module is operated; wherein the external fan start-up conditions include:

[0080] The shutdown time of the outdoor fan is greater than the third preset time; the sum of the exhaust temperature and the compensation temperature is less than the third preset temperature, and the third preset temperature is less than the first preset temperature; or the difference between the outdoor ambient temperature and the outlet temperature of the outdoor heat exchanger is greater than the first temperature difference threshold.

[0081] It should be noted that the above-mentioned detection module 61, high temperature prevention judgment module 62, high temperature prevention protection entry module 63, refrigerant shortage judgment module 64, refrigerant shortage protection entry module 65, and external fan start-up control module 66 correspond to the detection step, high temperature prevention judgment step, high temperature prevention protection entry step, refrigerant shortage judgment step, refrigerant shortage protection entry step and external fan start-up control step in the above-mentioned protection method. The examples and application scenarios implemented by each module and the corresponding steps are the same, but are not limited to the contents disclosed in the above-mentioned implementation method.

[0082] In a preferred embodiment of the present invention, the compensation temperature is associated with the outdoor ambient temperature and includes:

[0083] When the outdoor ambient temperature is greater than the first temperature threshold (such as 24°C), the compensation temperature is the first compensation temperature (such as 0°C);

[0084] If the outdoor ambient temperature is greater than the second temperature threshold and less than or equal to the first temperature threshold, the compensation temperature is the second compensation temperature (e.g., 4°C);

[0085] The outdoor ambient temperature is less than or equal to the second temperature threshold (eg, 14° C.), the compensation temperature is the third compensation temperature (eg, 7° C.), and the first temperature threshold is greater than the second temperature threshold.

[0086] By setting multiple temperature ranges and multiple compensation temperatures in the above manner, the accuracy of high temperature protection and refrigerant shortage judgment can be improved. Technicians can adjust the temperature threshold and compensation temperature value according to actual conditions. Preferably, the first compensation temperature range is -5 to 5°C, the second compensation temperature range is -5 to 5°C, and the third compensation temperature range is -5 to 5°C.

[0087] In a preferred embodiment of the present invention, the first preset temperature ranges from 70-100°C, preferably 82°C. The second preset temperature ranges from 90-110°C, preferably 105°C. The first preset duration is 3 minutes, the second preset duration is 2 minutes, and the third preset duration ranges from 3-10 minutes.

[0088] Another aspect of the present invention provides an air-conditioning system, comprising the above-mentioned protection device for preventing high temperature during heating and lack of refrigerant during heating of the air-conditioning system.

[0089] The present invention further provides a computer-readable storage medium storing a computer program that, when executed, implements the aforementioned method for protecting the air conditioning system from high-temperature heating and refrigerant shortage. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), a removable hard drive, a magnetic disk, or an optical disk.

[0090] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for protecting an air conditioning system from high temperature and lack of refrigerant during heating, wherein the air conditioning system comprises an indoor unit and an outdoor unit, wherein the outdoor unit comprises at least a compressor and an outdoor fan, wherein: The protection method includes the following steps: Testing steps: In heating mode, turn on the outdoor fan and detect the outdoor ambient temperature, the exhaust temperature of the compressor, the fan current of the outdoor fan, and the running time of the outdoor fan in real time; High temperature prevention judgment step: when the operating time is greater than a first preset time, comparing whether the sum of the exhaust temperature and the compensation temperature is greater than the first preset temperature and whether the fan current is greater than a preset current value; wherein the compensation temperature is associated with the outdoor ambient temperature; High temperature protection entry step: when the sum of the exhaust temperature and the compensation temperature is greater than a first preset temperature and the fan current is greater than a preset current value, controlling the outdoor fan to stop running and the indoor unit to operate normally; Refrigerant shortage judgment step: after the external fan stops running, judging whether the sum of the exhaust temperature and the compensation temperature is greater than a second preset temperature and lasts for a second time period; Refrigerant shortage protection entry step: when the sum of the exhaust temperature and the compensation temperature is greater than a second preset temperature and lasts for a second time period, the compressor is controlled to stop and a fault is reported.

2. The method for protecting the air conditioning system from high temperature and lack of refrigerant during heating according to claim 1, characterized in that: The air conditioning system is a non-communication fixed-frequency air conditioning system with indoor and outdoor units.

3. The method for protecting the air conditioning system from high temperature and lack of refrigerant during heating according to claim 2, characterized in that: In the high temperature prevention judgment step, associating the compensation temperature with the outdoor ambient temperature includes: When the outdoor ambient temperature is greater than a first temperature threshold, the compensation temperature is a first compensation temperature; The outdoor ambient temperature is greater than the second temperature threshold and less than or equal to the first temperature threshold, and the compensation temperature is the second compensation temperature; The outdoor ambient temperature is less than or equal to a second temperature threshold, the compensation temperature is a third compensation temperature, and the first temperature threshold is greater than the second temperature threshold.

4. The method for protecting the air conditioning system from high temperature and lack of refrigerant during heating according to claim 3, characterized in that: In the refrigerant shortage judgment step, the second preset temperature has a value range of 90-110°C.

5. The method for protecting the air conditioning system from high temperature and lack of refrigerant during heating according to claim 3, characterized in that: The outdoor unit further includes an outdoor heat exchanger, and the protection method further includes: The external fan start-up control step is to determine whether the external fan meets the external fan start-up conditions; if so, the external fan is started; if not, the process returns to the high temperature protection entry step; wherein the external fan start-up conditions include: The shutdown time of the external fan is longer than a third preset time; The sum of the exhaust temperature and the compensation temperature is less than a third preset temperature, and the third preset temperature is less than the first preset temperature; Or the difference between the outdoor ambient temperature and the outlet temperature of the outdoor heat exchanger is greater than a first temperature difference threshold.

6. The method for protecting the air conditioning system from high temperature and lack of refrigerant during heating according to claim 5, characterized in that: The third preset time length has a value range of 3-10 minutes.

7. The method for protecting an air-conditioning system from high temperature and lack of refrigerant during heating according to claim 5, characterized in that: The third preset temperature ranges from 70°C to 90°C.

8. The method for protecting an air-conditioning system from high temperature and lack of refrigerant during heating according to claim 5, characterized in that: The first temperature difference threshold value ranges from 10°C to 40°C.

9. A device for protecting an air-conditioning system from high temperature and lack of refrigerant during heating, characterized in that: include: The detection module is used to detect the outdoor ambient temperature, the exhaust temperature of the compressor, the fan current of the outdoor fan, and the operating time of the outdoor fan in real time under the condition that the outdoor fan is turned on in the heating mode; a high temperature prevention judgment module, configured to compare, when the operating time is greater than a first preset time, whether the sum of the exhaust temperature and the compensation temperature is greater than a first preset temperature and whether the fan current is greater than a preset current value; wherein the compensation temperature is associated with the outdoor ambient temperature; an anti-high temperature protection entry module, configured to control the outdoor fan to stop running and the indoor unit to operate normally when the sum of the exhaust temperature and the compensation temperature is greater than a first preset temperature and the fan current is greater than a preset current value; a refrigerant shortage judgment module, configured to judge whether the sum of the exhaust temperature and the compensation temperature is greater than a second preset temperature and lasts for a second time period after the external fan stops running; The refrigerant shortage protection entry module is used to control the compressor to stop and report a fault when the sum of the exhaust temperature and the compensation temperature is greater than a second preset temperature and lasts for a second time period.

10. An air conditioning system, characterized in that: The invention comprises the protection device for preventing high temperature and lack of refrigerant during heating of the air-conditioning system as claimed in claim 9.

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