A control method and device of an air conditioner, the air conditioner and a storage medium

Abstract

The application discloses a control method and device of an air conditioner, the air conditioner and a storage medium, and relates to the technical field of air conditioners. The method comprises the following steps: after the air conditioner is started and refrigeration is performed for a first set time, it is determined whether the refrigerant circulation amount of the air conditioner is normal according to the middle temperature of the inner pipe of the air conditioner and the pressure on the suction pipe of the compressor; if it is determined that the refrigerant circulation amount of the air conditioner is normal, the middle temperature of the inner pipe of the air conditioner is used to control the compressor to operate at a reduced frequency or to stop defrosting; and if it is determined that the refrigerant circulation amount of the air conditioner is abnormal, the middle temperature of the inner pipe of the air conditioner and the suction saturation temperature of the compressor are used to control the compressor to operate at a reduced frequency or to stop defrosting. According to the scheme, the middle temperature of the evaporator and the pressure on the suction pipe of the compressor are combined to realize different degrees of control, such as compressor frequency reduction and stop defrosting, to timely prevent the evaporator from freezing or defrosting, and the reliability and safety of air conditioner operation are improved.

Description

Technical Field

[0001] This invention belongs to the field of air conditioner technology, specifically relating to a control method, device, air conditioner, and storage medium for an air conditioner, and particularly to a control method, device, air conditioner, and storage medium for preventing frost formation on the indoor heat exchanger in an air conditioner. Background Technology

[0002] When an air conditioner is running in cooling mode, in a low-temperature environment, when warm, humid air passes over the evaporator surface (which is below the dew point of the air), water vapor in the air condenses into water on the surface. When the evaporator surface temperature is below the freezing point of water, the condensed water forms frost. As water vapor in the air continuously moves towards the cold surface (the evaporator surface) and condenses under pressure, the density and thickness of the frost layer continuously increase. Persistent frost or ice buildup on the evaporator surface reduces airflow area, leading to a rapid decrease in overall cooling efficiency, frost clogging the drain and causing leaks, compressor wear due to liquid return during air intake, and even malfunctions of the air conditioner's refrigerant system.

[0003] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The purpose of this invention is to provide a control method, device, air conditioner, and storage medium for an air conditioner, to solve the problem that persistent frost or ice buildup on the evaporator surface during air conditioner cooling operation can lead to a rapid decline in the overall cooling effect or even paralysis of the refrigerant system, affecting the reliability and safety of the air conditioner's operation. The invention achieves different levels of control by combining the temperature in the middle of the evaporator and the pressure on the compressor's suction pipe, such as reducing the compressor frequency and stopping for defrosting. Whether the refrigerant level is normal or insufficient, the invention can promptly prevent evaporator freezing or defrost, thus improving the reliability and safety of the air conditioner's operation.

[0005] This invention provides a control method for an air conditioner, wherein the air conditioner includes a compressor and an indoor heat exchanger; the control method includes: after the air conditioner is turned on and operates in cooling mode for a first set time, acquiring the mid-temperature of the indoor heat exchanger, and recording it as the mid-temperature of the inner pipe of the air conditioner; acquiring the pressure on the pipe where the compressor's suction port is located, and recording it as the suction pressure of the compressor; determining the saturation temperature corresponding to the suction pressure of the compressor, and recording it as the suction saturation temperature of the compressor; determining whether the refrigerant circulation of the air conditioner is normal based on the mid-temperature of the inner pipe of the air conditioner and the suction saturation temperature of the compressor; if the refrigerant circulation of the air conditioner is determined to be normal, controlling the compressor to operate at a reduced frequency or to stop for defrosting based on the mid-temperature of the inner pipe of the air conditioner; if the refrigerant circulation of the air conditioner is determined to be abnormal, controlling the compressor to operate at a reduced frequency or to stop for defrosting based on the mid-temperature of the inner pipe of the air conditioner and the suction saturation temperature of the compressor.

[0006] In some embodiments, determining whether the refrigerant circulation of the air conditioner is normal based on the temperature at the middle of the air conditioner's inner pipe and the suction saturation temperature of the compressor includes: determining whether the absolute value of the difference between the temperature at the middle of the air conditioner's inner pipe and the suction saturation temperature of the compressor is less than or equal to a first set temperature difference threshold, and determining whether the temperature at the middle of the air conditioner's inner pipe is less than or equal to the suction saturation temperature of the compressor; if it is determined that the absolute value of the difference between the temperature at the middle of the air conditioner's inner pipe and the suction saturation temperature of the compressor is less than or equal to the first set temperature difference threshold, then determining that the air conditioner's refrigerant circulation is normal. The refrigerant circulation of the air conditioner is normal. If the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is greater than the first set temperature difference threshold, and the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the suction saturation temperature of the compressor, then the refrigerant circulation of the air conditioner is normal. If the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is greater than the first set temperature difference threshold, and the temperature at the middle of the inner pipe of the air conditioner is greater than the suction saturation temperature of the compressor, then the refrigerant circulation of the air conditioner is abnormal.

[0007] In some embodiments, controlling the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the center of the air conditioner's inner pipe includes: determining whether the temperature at the center of the air conditioner's inner pipe is detected to be less than or equal to a first set temperature for a continuous second set time; if it is determined that the temperature at the center of the air conditioner's inner pipe is not detected to be less than or equal to the first set temperature for a continuous second set time, then controlling the compressor to operate at a frequency set in the cooling mode; if it is determined that the temperature at the center of the air conditioner's inner pipe is detected to be less than or equal to the first set temperature for a continuous second set time, then controlling the compressor to operate at a frequency set in the cooling mode and prohibiting the compressor from increasing its frequency.

[0008] In some embodiments, controlling the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the center of the air conditioner's inner pipe further includes: after controlling the compressor to operate at a frequency programmed in cooling mode and prohibiting the compressor from increasing its frequency, determining whether the temperature at the center of the air conditioner's inner pipe is less than or equal to a second set temperature within a third consecutive set time period; wherein the second set temperature is less than a first set temperature; if it is determined that the temperature at the center of the air conditioner's inner pipe is not less than or equal to the second set temperature within a third consecutive set time period, then, while controlling the compressor to operate at a frequency programmed in cooling mode and prohibiting the compressor from increasing its frequency, returning to the previous state to re-determine whether the temperature at the center of the air conditioner's inner pipe is less than or equal to the first set temperature within a second consecutive set time period; if it is determined that the temperature at the center of the air conditioner's inner pipe is less than or equal to the second set temperature within a third consecutive set time period, then controlling the compressor to operate at a reduced frequency; wherein controlling the compressor to operate at a reduced frequency includes: controlling the compressor's frequency to decrease by a first set frequency every fourth set time period, and controlling the compressor to operate at the reduced frequency.

[0009] In some embodiments, controlling the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the center of the air conditioner's inner pipe further includes: after controlling the compressor to operate at a reduced frequency, determining whether the temperature at the center of the air conditioner's inner pipe is detected to be less than or equal to a third set temperature within a continuous fifth set time period; wherein the third set temperature is less than a second set temperature; if it is determined that the temperature at the center of the air conditioner's inner pipe is detected to be less than or equal to the third set temperature within a continuous fifth set time period, then controlling the compressor to stop for defrosting; if it is determined that the temperature at the center of the air conditioner's inner pipe is not detected to be less than or equal to the third set temperature within a continuous fifth set time period, then, while controlling the compressor to operate at a reduced frequency, returning to the previous state to re-determine whether the temperature at the center of the air conditioner's inner pipe is detected to be less than or equal to the second set temperature within a continuous third set time period.

[0010] In some embodiments, controlling the compressor to operate at reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor includes: for the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor obtained every sixth set time interval, recording the temperature at the middle of the inner pipe of the air conditioner obtained in two consecutive intervals as the i-th temperature at the middle of the inner pipe and the (i+1)-th temperature at the middle of the inner pipe; and recording the suction saturation temperature of the compressor obtained in two consecutive intervals as the i-th suction saturation temperature and the (i+1)-th suction saturation temperature; where i is the first of the two consecutive acquisition times. The number of acquisitions is set, where i is a positive integer and i+1 is the number of acquisitions in the next two consecutive acquisitions. It is determined whether the following conditions are met: the temperature at the middle of the (i+1)th inner tube is lower than the temperature at the middle of the ith inner tube, the (i+1)th suction saturation temperature is lower than the ith suction saturation temperature, and the difference between the (i+1)th inner tube temperature and the temperature at the middle of the ith inner tube is greater than or equal to a second set temperature threshold. If these conditions are not met, the compressor is controlled to operate at the frequency set in the cooling mode. If these conditions are met, the compressor is controlled to operate at the frequency set in the cooling mode, and frequency increases of the compressor are prohibited.

[0011] In some embodiments, controlling the compressor to operate at a reduced frequency or to stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor further includes: after controlling the compressor to operate at a frequency set in the cooling mode and prohibiting the compressor from increasing its frequency, determining whether the following conditions are met: the (i+1)th inner pipe middle temperature obtained for a second set number of consecutive cycles is less than the ith inner pipe middle temperature, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner pipe middle temperature and the ith inner pipe middle temperature is greater than or equal to a second set temperature threshold; wherein the second set number of cycles is greater than the first set number of cycles; if not met, then in the control... If the compressor operates at the frequency set in the cooling mode and frequency increase of the compressor is prohibited, the process returns to re-determine whether the following conditions are met: the temperature of the (i+1)th inner tube center is lower than the temperature of the ith inner tube center, the (i+1)th suction saturation temperature is lower than the ith suction saturation temperature, and the difference between the (i+1)th inner tube center temperature and the temperature of the ith inner tube center is greater than or equal to the second set temperature threshold. If these conditions are met, the compressor is controlled to operate at a reduced frequency. Controlling the compressor to operate at a reduced frequency includes: controlling the compressor frequency to decrease by the second set frequency every seventh set time interval, and controlling the compressor to operate at the reduced frequency.

[0012] In some embodiments, controlling the compressor to operate at reduced frequency or to stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor further includes: after controlling the compressor to operate at reduced frequency, executing a first judgment logic and / or executing a second judgment logic; wherein, the first judgment logic is: determining whether the conditions are met for a third consecutive set number of times that the (i+1)th inner pipe middle temperature is less than the ith inner pipe middle temperature, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner pipe middle temperature and the ith inner pipe middle temperature is greater than or equal to a second set temperature threshold; the second judgment logic is: determining whether the conditions are met for a fourth consecutive set number of times that the (i+1)th inner pipe middle temperature is less than the ith inner pipe middle temperature, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner pipe middle temperature and the ith inner pipe middle temperature is greater than or equal to a second set temperature threshold; The difference between the temperature at the middle of the i-th inner tube and the temperature at the middle of the i-th inner tube is less than the second set temperature threshold; wherein, the third set number of times is greater than the second set number of times; if the judgment result of the first judgment logic is not satisfied, then under the condition of controlling the compressor to operate at a reduced frequency, return to re-determine whether the conditions are met: the temperature at the middle of the (i+1)-th inner tube obtained for the second set number of consecutive times is less than the temperature at the middle of the i-th inner tube, the (i+1)-th suction saturation temperature is less than the temperature at the i-th suction saturation temperature, and the difference between the temperature at the middle of the (i+1)-th inner tube and the temperature at the middle of the i-th inner tube is greater than or equal to the second set temperature threshold; if the judgment result of the first judgment logic is satisfied, then control the compressor to stop for defrosting; if the judgment result of the second judgment logic is not satisfied, then under the condition of controlling the compressor to operate at a reduced frequency, execute the first judgment logic; if the judgment result of the second judgment logic is satisfied, then control the compressor to stop for defrosting.

[0013] In conjunction with the above method, another aspect of the present invention provides a control device for an air conditioner, the air conditioner having a compressor and an indoor heat exchanger; the control device for the air conditioner includes: an acquisition unit configured to acquire, after the air conditioner is turned on and running in cooling mode for a first set time, acquire the middle temperature of the indoor heat exchanger, denoted as the middle temperature of the inner pipe of the air conditioner; and acquire the pressure on the pipe where the suction port of the compressor is located, denoted as the suction pressure of the compressor; and a control unit configured to determine, based on the suction pressure of the compressor, a saturation temperature corresponding to the suction pressure of the compressor, denoted as the pressure... The control unit is further configured to determine whether the refrigerant circulation of the air conditioner is normal based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor; the control unit is further configured to, if it is determined that the refrigerant circulation of the air conditioner is normal, control the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner; the control unit is further configured to, if it is determined that the refrigerant circulation of the air conditioner is abnormal, control the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor.

[0014] In some embodiments, the control unit determines whether the refrigerant circulation of the air conditioner is normal based on the temperature at the middle of the air conditioner's inner pipe and the suction saturation temperature of the compressor. This includes: determining whether the absolute value of the difference between the temperature at the middle of the air conditioner's inner pipe and the suction saturation temperature of the compressor is less than or equal to a first set temperature difference threshold, and determining whether the temperature at the middle of the air conditioner's inner pipe is less than or equal to the suction saturation temperature of the compressor; if it is determined that the absolute value of the difference between the temperature at the middle of the air conditioner's inner pipe and the suction saturation temperature of the compressor is less than or equal to the first set temperature difference threshold, then... The refrigerant circulation of the air conditioner is normal. If the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is greater than the first set temperature difference threshold, and the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the suction saturation temperature of the compressor, then the refrigerant circulation of the air conditioner is normal. If the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is greater than the first set temperature difference threshold, and the temperature at the middle of the inner pipe of the air conditioner is greater than the suction saturation temperature of the compressor, then the refrigerant circulation of the air conditioner is abnormal.

[0015] In some embodiments, the control unit controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the center of the air conditioner's inner pipe, including: determining whether the temperature at the center of the air conditioner's inner pipe is detected to be less than or equal to a first set temperature for a continuous second set time; if it is determined that the temperature at the center of the air conditioner's inner pipe is not detected to be less than or equal to the first set temperature for a continuous second set time, then controlling the compressor to operate at a frequency set in the cooling mode; if it is determined that the temperature at the center of the air conditioner's inner pipe is detected to be less than or equal to the first set temperature for a continuous second set time, then controlling the compressor to operate at a frequency set in the cooling mode and prohibiting the compressor from increasing its frequency.

[0016] In some embodiments, the control unit, based on the temperature at the center of the air conditioner's inner pipe, controls the compressor to operate at a reduced frequency or stop for defrosting. This further includes: after controlling the compressor to operate at a frequency programmed in cooling mode and prohibiting the compressor from increasing its frequency, determining whether the temperature at the center of the air conditioner's inner pipe is less than or equal to a second set temperature within a third consecutive set time period; wherein the second set temperature is less than a first set temperature; if it is determined that the temperature at the center of the air conditioner's inner pipe is not less than or equal to the second set temperature within the third consecutive set time period, then, while controlling the compressor to operate at the frequency programmed in cooling mode and prohibiting the compressor from increasing its frequency, returning to the previous state to re-determine whether the temperature at the center of the air conditioner's inner pipe is less than or equal to the first set temperature within a second consecutive set time period; if it is determined that the temperature at the center of the air conditioner's inner pipe is less than or equal to the second set temperature within a third consecutive set time period, then controlling the compressor to operate at a reduced frequency; wherein controlling the compressor to operate at a reduced frequency includes: controlling the compressor's frequency to decrease by a first set frequency every fourth set time period, and controlling the compressor to operate at the reduced frequency.

[0017] In some embodiments, the control unit, based on the temperature at the center of the air conditioner's inner pipe, controls the compressor to operate at a reduced frequency or to stop for defrosting. This further includes: after controlling the compressor to operate at a reduced frequency, determining whether the temperature at the center of the air conditioner's inner pipe is detected to be less than or equal to a third set temperature within a fifth consecutive set time period; wherein the third set temperature is less than a second set temperature; if it is determined that the temperature at the center of the air conditioner's inner pipe is detected to be less than or equal to the third set temperature within a fifth consecutive set time period, then controlling the compressor to stop for defrosting; if it is determined that the temperature at the center of the air conditioner's inner pipe is not detected to be less than or equal to the third set temperature within a fifth consecutive set time period, then, while controlling the compressor to operate at a reduced frequency, returning to the previous state to re-determine whether the temperature at the center of the air conditioner's inner pipe is detected to be less than or equal to the second set temperature within a third consecutive set time period.

[0018] In some embodiments, the control unit controls the compressor to operate at reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor. This includes: for the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor obtained every sixth set time interval, recording the temperature at the middle of the inner pipe of the air conditioner obtained in two consecutive intervals as the i-th temperature at the middle of the inner pipe and the (i+1)-th temperature at the middle of the inner pipe; and recording the suction saturation temperature of the compressor obtained in two consecutive intervals as the i-th suction saturation temperature and the (i+1)-th suction saturation temperature; where i is the number of consecutive acquisition intervals. The number of times the previous acquisition was obtained, where i is a positive integer and i+1 is the number of times the acquisition was obtained in the next two consecutive acquisitions; it is determined whether the following conditions are met: the temperature of the middle part of the (i+1)th inner tube is less than the temperature of the middle part of the ith inner tube, the saturation temperature of the (i+1)th intake is less than the saturation temperature of the ith intake, and the difference between the temperature of the (i+1)th inner tube and the temperature of the middle part of the ith inner tube is greater than or equal to the second set temperature threshold; if not, the compressor is controlled to operate at the frequency set in the program under the refrigeration mode; if the conditions are met, the compressor is controlled to operate at the frequency set in the program under the refrigeration mode, and the frequency increase of the compressor is prohibited.

[0019] In some embodiments, the control unit, based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor, controls the compressor to operate at a reduced frequency or stop for defrosting. This further includes: after controlling the compressor to operate at a frequency programmed in cooling mode and prohibiting the compressor from increasing its frequency, determining whether the following conditions are met: the (i+1)th inner pipe middle temperature obtained for a second set number of consecutive cycles is less than the ith inner pipe middle temperature, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner pipe middle temperature and the ith inner pipe middle temperature is greater than or equal to a second set temperature threshold; wherein the second set number of cycles is greater than the first set number of cycles; if not met, If the compressor is controlled to operate at the frequency set in the cooling mode and the frequency increase of the compressor is prohibited, the process returns to re-determine whether the following conditions are met: the temperature of the (i+1)th inner tube center is less than the temperature of the ith inner tube center, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner tube center temperature and the temperature of the ith inner tube center is greater than or equal to the second set temperature threshold. If these conditions are met, the compressor is controlled to operate at a reduced frequency. Controlling the compressor to operate at a reduced frequency includes: controlling the compressor frequency to decrease by the second set frequency every seventh set time interval, and controlling the compressor to operate at the reduced frequency.

[0020] In some embodiments, the control unit, based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor, controls the compressor to operate at a reduced frequency or to stop for defrosting, further includes: after controlling the compressor to operate at a reduced frequency, executing a first judgment logic and / or executing a second judgment logic; wherein, the first judgment logic is: determining whether the conditions are met for a third consecutive set number of times that the (i+1)th inner pipe middle temperature is less than the ith inner pipe middle temperature, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner pipe middle temperature and the ith inner pipe middle temperature is greater than or equal to a second set temperature threshold; the second judgment logic is: determining whether the conditions are met for a fourth consecutive set number of times that the (i+1)th inner pipe middle temperature is less than the ith inner pipe middle temperature, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner pipe middle temperature and the ith inner pipe middle temperature is greater than or equal to a second set temperature threshold; The difference between the temperature of the first inner tube and the temperature of the middle inner tube of the i-th inner tube is less than the second set temperature threshold; wherein, the third set number of times is greater than the second set number of times; if the judgment result of the first judgment logic is not satisfied, then under the condition of controlling the compressor to operate at a reduced frequency, return to re-determine whether the conditions are met: the temperature of the middle inner tube of the (i+1)-th inner tube obtained for the second set number of consecutive times is less than the temperature of the middle inner tube of the i-th inner tube, the temperature of the (i+1)-th inner tube is less than the temperature of the saturated suction air of the i-th inner tube, and the difference between the temperature of the middle inner tube of the (i+1)-th inner tube and the temperature of the middle inner tube of the i-th inner tube is greater than or equal to the second set temperature threshold; if the judgment result of the first judgment logic is satisfied, then control the compressor to stop for defrosting; if the judgment result of the second judgment logic is not satisfied, then under the condition of controlling the compressor to operate at a reduced frequency, execute the first judgment logic; if the judgment result of the second judgment logic is satisfied, then control the compressor to stop for defrosting.

[0021] In conjunction with the above-described device, the present invention further provides an air conditioner, comprising: the control device for the air conditioner described above.

[0022] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device on which the storage medium is located controls the air conditioner control method described above to be performed.

[0023] Therefore, the solution of this invention detects the temperature in the middle of the evaporator and the pressure on the compressor suction pipe after the air conditioner is turned on for cooling. Based on the temperature in the middle of the evaporator and the pressure on the compressor suction pipe, it determines whether the refrigerant circulation is normal. When the refrigerant circulation is normal, the compressor frequency is controlled based on the temperature in the middle of the evaporator. When the refrigerant circulation is abnormal, the compressor frequency is controlled based on the temperature in the middle of the evaporator and the pressure on the compressor suction pipe. This achieves different levels of control, such as reducing the compressor frequency and stopping for defrosting. Thus, by combining the temperature in the middle of the evaporator and the pressure on the compressor suction pipe, different levels of control, such as reducing the compressor frequency and stopping for defrosting, are achieved. Regardless of whether the refrigerant quantity of the unit is normal or the refrigerant circulation is insufficient, the evaporator can be prevented from freezing or defrosted in a timely manner, improving the reliability and safety of the air conditioner operation.

[0024] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1 This is a flow path diagram of an embodiment of the control method for an air conditioner of the present invention;

[0027] Figure 2 This is a flow path diagram of an embodiment of the method of the present invention for determining whether the refrigerant circulation volume of the air conditioner is normal;

[0028] Figure 3 This is a schematic diagram of the flow path of an embodiment of the first control logic in the method of the present invention, which controls the compressor to operate at reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is normal.

[0029] Figure 4 This is a schematic diagram of the flow path of an embodiment of the second control logic in the method of the present invention, which controls the compressor to operate at reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is normal.

[0030] Figure 5 This is a flow diagram of an embodiment of the third control logic in the method of the present invention, which controls the compressor to operate at reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is normal.

[0031] Figure 6 This is a flow diagram of an embodiment of the first control logic in the method of the present invention, which controls the compressor to operate at reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is abnormal.

[0032] Figure 7 This is a flow diagram of an embodiment of the second control logic in the method of the present invention, which controls the compressor to operate at reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is abnormal.

[0033] Figure 8 This is a flow diagram of an embodiment of the third control logic in the method of the present invention, which controls the compressor to operate at reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is abnormal.

[0034] Figure 9 This is a schematic diagram of the structure of an embodiment of the control device for an air conditioner according to the present invention;

[0035] Figure 10 A schematic diagram of the structure of an embodiment of an air conditioner;

[0036] Figure 11 This is a flow path diagram of an embodiment of a control method for preventing frost formation on the indoor heat exchanger in an air conditioner.

[0037] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0038] 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0040] Considering that persistent frost or ice buildup on the evaporator surface during air conditioner cooling operation can lead to a rapid decline in overall cooling efficiency and even cause refrigerant system malfunction, affecting the reliability and safety of the air conditioner, timely and effective defrosting is crucial for improving the performance and reliability of the air conditioner.

[0041] The evaporator defrosting technology in related solutions mainly involves installing a temperature sensor on the copper tube in the middle of the evaporator flow path. When the temperature sensor detects a temperature lower than a set value, it triggers the evaporator anti-freezing or defrosting action. This control method can effectively prevent or resolve evaporator frosting when the refrigerant circulation is normal. However, when the unit is short of refrigerant or the refrigerant system is clogged, the following situations prevent timely anti-freezing or defrosting: the evaporator flow path inlet temperature is below the freezing point, frost begins to form at the evaporator flow path inlet, and due to insufficient refrigerant circulation, after heat exchange with the air, the temperature in the middle of the evaporator is higher than or far higher than the freezing point of water. At this time, the temperature detected by the temperature sensor in the middle of the evaporator does not reach the condition for anti-freezing or defrosting action. As the unit operates, the frost at the evaporator flow path inlet gradually thickens and spreads towards the evaporator flow path outlet. At this time, the temperature in the middle of the evaporator also gradually decreases, and when the condition for anti-freezing or defrosting action is reached, the anti-freezing or defrosting action is executed. Because a lot of frost accumulates at the evaporator flow path inlet, the frost on the evaporator cannot be completely melted after the antifreeze or defrost action is performed, and it will gradually accumulate during subsequent operation, resulting in a rapid decrease in the overall cooling effect, frost blocking the drain outlet and causing water leakage, compressor wear due to air intake and liquid return, and even paralysis of the air conditioner's refrigerant system.

[0042] Therefore, the present invention proposes a control method for an air conditioner, specifically a method to prevent frost formation on the indoor heat exchanger. A pressure sensor is installed on the compressor suction pipe to accurately detect the compressor's suction superheat. Then, after the air conditioner is turned on for cooling, the refrigerant circulation rate is determined based on the evaporator's mid-section temperature and the compressor's suction superheat. Based on the determination result, the compressor frequency is limited in stages, achieving different levels of control such as reducing the compressor frequency and stopping for defrosting. Whether the refrigerant level is normal or the refrigerant circulation rate is insufficient, timely anti-freezing or defrosting of the evaporator can be performed, preventing persistent frost or ice buildup on the evaporator surface. The refrigerant circulation rate is the refrigerant mass flow rate through the evaporator, measured in kg / s.

[0043] According to embodiments of the present invention, a control method for an air conditioner is provided, such as... Figure 1 The diagram shows a flow path of one embodiment of the method of the present invention. The air conditioner includes a compressor and an indoor heat exchanger. Specifically, Figure 10 This is a schematic diagram of the structure of one embodiment of an air conditioner. In cooling mode, as... Figure 10The air conditioner shown includes: a compressor, a condenser, an evaporator, a four-way valve, and an electronic expansion valve. The compressor's discharge port is connected to the first port of the four-way valve; the second port of the four-way valve, after passing through the condenser, the electronic expansion valve, and the evaporator, is connected to the fourth port of the four-way valve; the third port of the four-way valve is connected to the compressor's suction port. A discharge temperature sensor is installed on the pipeline between the compressor's discharge port and the first port of the four-way valve; a pressure sensor (i.e., a pressure sensor is installed on the compressor's suction pipe) is installed on the pipeline between the third port of the four-way valve and the compressor's suction port; an outdoor ambient temperature sensor and a temperature sensor in the middle of the condenser are installed at the condenser; an indoor ambient temperature sensor and a temperature sensor in the middle of the evaporator are installed at the evaporator; a shut-off valve is installed on the pipeline where the evaporator inlet is located; and another shut-off valve is installed on the pipeline where the evaporator outlet is located. Preferably, as shown... Figure 10 The air conditioner shown also includes filters for filtering impurities; there can be more than two filters, for example: a filter is installed on the pipeline between another shut-off valve on the pipeline where the evaporator outlet is located and the fourth valve port of the four-way valve; a filter is installed on the pipeline between the condenser outlet and the inlet of the electronic expansion valve; a filter is installed between a shut-off valve on the pipeline where the electronic expansion valve outlet is located and the evaporator inlet, and so on.

[0044] In the solution of the present invention, such as Figure 1 As shown, the control method of the air conditioner includes steps S110 to S150.

[0045] In step S110, after the air conditioner is turned on and has been running in cooling mode for a first set time, the temperature at the middle of the indoor heat exchanger is obtained and recorded as the temperature at the middle of the inner pipe of the air conditioner, such as the temperature at the middle of the evaporator T. sm And obtain the pressure on the pipeline where the compressor's suction port is located, and record it as the compressor's suction pressure, such as the unit's low-pressure P. S The first set time is, for example, time t1. Specifically, Figure 11 This is a flow path diagram of an embodiment of a control method for preventing frost buildup on the indoor heat exchanger in an air conditioner. Figure 11 The control method shown for preventing frost buildup on the indoor heat exchanger in an air conditioner includes: Step 1, turning on the air conditioner in cooling mode and detecting the temperature T in the middle of the evaporator. sm Unit low pressure P S Low pressure corresponds to saturation temperature T sat Then proceed to step 2. For example... Figure 10 The unit shown is equipped with a temperature sensor in the middle of the evaporator and a pressure sensor located on the compressor suction pipe. The temperature sensor in the middle of the evaporator can be used to detect the temperature T in the middle of the evaporator. smThe low-pressure P of the unit can be detected using a pressure sensor located on the compressor suction pipe. S .

[0046] In step S120, based on the compressor's suction pressure, the saturation temperature corresponding to the compressor's suction pressure is determined and denoted as the compressor's suction saturation temperature. For example, the saturation temperature T corresponds to the low pressure. sat Specifically, such as Figure 11 The control method for preventing frost buildup on the indoor heat exchanger in an air conditioner, as shown, further includes: in step 1, a pressure sensor located on the compressor suction pipe can detect the low-pressure P of the unit. S According to the low pressure P of the unit S The compressor's suction saturation temperature T corresponding to the compressor's low-pressure setting can be calculated. sat .

[0047] In step S130, when the air conditioner has been running for a cooling time for a first set time, the refrigerant circulation of the air conditioner is determined to be normal based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor.

[0048] In some embodiments, the specific process of determining whether the refrigerant circulation volume of the air conditioner is normal based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor in step S130 is illustrated in the following exemplary description.

[0049] The following is combined Figure 2 The diagram shows a flow path diagram of an embodiment of the method of the present invention for determining whether the refrigerant circulation volume of the air conditioner is normal. It further illustrates the specific process of determining whether the refrigerant circulation volume of the air conditioner is normal in step S130, including steps S210 to S240.

[0050] Step S210: Determine whether the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is less than or equal to a first set temperature difference threshold, and determine whether the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the suction saturation temperature of the compressor. The first set temperature difference threshold is, for example, temperature ΔT1. Specifically, as shown... Figure 11 The control method for preventing frost buildup on the indoor heat exchanger in an air conditioner, as shown, further includes: Step 2, after the unit has been running for t1, performing the judgments in steps 21, 22, and 23, and then selectively performing either step 3 or step 4 based on the judgment results. The value of time t1 ranges from 30 min to 120 min, for example, t1 can be set to 60 min.

[0051] Step S220: If the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is less than or equal to a first set temperature difference threshold, then the refrigerant circulation of the air conditioner is determined to be normal. Specifically, as follows... Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 21, if | the compressor's suction saturation temperature T sat -Evaporator mid-temperature T sm If the temperature ΔT1 is less than or equal to the unit's temperature, then the refrigerant circulation is considered normal, and step 3 is then executed. The temperature ΔT1 ranges from 2℃ to 6℃; for example, if ΔT1 is set to 5℃.

[0052] Step S230: If it is determined that the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is greater than a first set temperature difference threshold, and it is determined that the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the suction saturation temperature of the compressor, then it is determined that the refrigerant circulation of the air conditioner is normal. Specifically, as follows... Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 22, if | the compressor's suction saturation temperature T sat -Evaporator mid-temperature T sm |>Temperature ΔT1 and temperature T in the middle of the evaporator sm ≤Compressor suction saturation temperature T sat If the refrigerant circulation rate of the unit is normal, then step 3 is executed. The temperature ΔT1 ranges from 2℃ to 6℃; for example, if ΔT1 is set to 5℃.

[0053] Step S240: If it is determined that the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is greater than a first set temperature difference threshold, and it is determined that the temperature at the middle of the inner pipe of the air conditioner is greater than the suction saturation temperature of the compressor, then it is determined that the refrigerant circulation of the air conditioner is abnormal. Specifically, as follows... Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 23, if | the compressor's suction saturation temperature T sat -Evaporator mid-temperature T sm |>Temperature ΔT1 and temperature T in the middle of the evaporator sm >Compressor suction saturation temperature T sat If the refrigerant circulation is insufficient, then step 4 is executed. The temperature ΔT1 ranges from 2℃ to 6℃; for example, if ΔT1 is set to 5℃.

[0054] In step S140, if it is determined that the refrigerant circulation of the air conditioner is normal, the compressor is controlled to operate at a reduced frequency or stop to defrost based on the temperature in the middle of the inner pipe of the air conditioner, so as to prevent the refrigerant system of the air conditioner from fluctuating due to excessive adjustment.

[0055] In some embodiments, step S140, when it is determined that the refrigerant circulation volume of the air conditioner is normal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature in the middle of the inner pipe of the air conditioner, including: a first control logic that controls the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is normal.

[0056] The following is combined Figure 3 The diagram shows an embodiment of the flow path of the first control logic for controlling the compressor to operate at a reduced frequency or to stop defrosting when the refrigerant circulation of the air conditioner is normal. It further illustrates the specific process of the first control logic for controlling the compressor to operate at a reduced frequency or to stop defrosting when the refrigerant circulation of the air conditioner is normal in step S140, including steps S310 to S330.

[0057] Step S310: Determine whether the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the first set temperature within a continuous second set time period. The second set time is, for example, time t2, and the first set temperature is, for example, temperature T1.

[0058] Step S320: If it is determined that the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the first set temperature within a continuous second set time, then the compressor is controlled to run at the frequency set in the cooling mode, that is, the compressor is controlled to run normally.

[0059] Step S330: If it is determined that the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the first set temperature within a continuous second set time, then the compressor is controlled to run at the frequency set in the cooling mode, and the frequency of the compressor is prohibited from increasing.

[0060] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: Step 3, the anti-freezing and defrosting control process when the refrigerant circulation rate of the unit is normal, see steps 31, 32, and 33. Specifically, step 31 involves determining whether the temperature T in the middle of the evaporator is detected continuously for time t2. sm ≤Temperature T1: If so, the temperature T in the middle of the evaporator is detected continuously over time t2. sm If the temperature is ≤T1, the compressor is not allowed to increase its frequency, and then step 32 is executed; otherwise, the air conditioner operates normally. This is provided that the continuous time t2 does not detect the evaporator mid-temperature T. smThe air conditioner will operate normally if the temperature is ≤T1; that is, compressor 1 is not allowed to increase its frequency under two conditions: ① continuous time t2, ② temperature T in the middle of the evaporator. sm The air conditioner will operate normally as long as either temperature T1 or time t2 is less than or equal to 3 minutes. The temperature T1 will range from 2℃ to 6℃, for example, 4℃.

[0061] In some embodiments, step S140, when it is determined that the refrigerant circulation volume of the air conditioner is normal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature in the middle of the inner pipe of the air conditioner. It further includes a second control logic that controls the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is normal.

[0062] The following is combined Figure 4 The diagram shows an embodiment of the flow path of the second control logic for controlling the compressor to operate at a reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is normal. It further illustrates the specific process of the second control logic for controlling the compressor to operate at a reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is normal in step S140, including steps S410 to S430.

[0063] Step S410: After controlling the compressor to operate at the frequency set in the cooling mode and prohibiting the compressor from increasing its frequency, determine whether the temperature at the middle of the air conditioner's inner pipe is less than or equal to the second set temperature within a third consecutive set time period. The second set temperature is less than the first set temperature; the third set time is, for example, time t3, and the second set temperature is, for example, temperature T2.

[0064] Step S420: If it is determined that the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the second set temperature within a third consecutive set time period, then, while controlling the compressor to run at the frequency set in the cooling mode and prohibiting the compressor from increasing its frequency, return to re-determine whether the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the first set temperature within a second consecutive set time period.

[0065] Step S430: If it is determined that the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the second set temperature within a third consecutive set time period, then the compressor is controlled to operate at a reduced frequency. Controlling the compressor to operate at a reduced frequency includes: controlling the compressor frequency to decrease by a first set frequency every fourth set time period, and controlling the compressor to operate at the reduced frequency. The fourth set time period is, for example, time t4, and the first set frequency is, for example, frequency X Hz.

[0066] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 32, determining whether the temperature T in the middle of the evaporator is detected continuously for time t3. sm ≤Temperature T2: If so, the temperature T in the middle of the evaporator is detected over a continuous time t3. sm When the temperature is ≤ T2, the compressor reduces the frequency by X Hz every time t4. The frequency reduction can only be performed once within time t4, and then step 33 is executed; otherwise, return to step 31.

[0067] The values ​​for time t3 range from 2 min to 6 min, such as 3 min. The values ​​for temperature T2 range from 0 to 5℃, such as 2℃. The values ​​for time t4 range from 1 min to 10 min, such as 5 min. The values ​​for frequency X range from 5 Hz to 15 Hz, such as 10 Hz.

[0068] In some embodiments, step S140, when it is determined that the refrigerant circulation volume of the air conditioner is normal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature in the middle of the inner pipe of the air conditioner. It further includes a third control logic that controls the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is normal.

[0069] The following is combined Figure 5 The diagram shows an embodiment of the flow path of the third control logic in the method of the present invention, which controls the compressor to operate at a reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is normal. The diagram further illustrates the specific process of the third control logic in step S140, which controls the compressor to operate at a reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is normal, including steps S510 to S530.

[0070] Step S510: After controlling the compressor to operate at a reduced frequency, determine whether the temperature at the middle of the air conditioner's inner pipe is less than or equal to a third set temperature within a continuous fifth set time period; wherein the third set temperature is less than the second set temperature. The fifth set time is, for example, time t5, and the third set temperature is, for example, temperature T3.

[0071] Step S520: If it is determined that the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the third set temperature within a continuous fifth set time, then the compressor is controlled to stop for defrosting.

[0072] Step S530: If it is determined that the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the third set temperature within a continuous fifth set time period, then the process returns to the previous step while controlling the compressor to operate at a reduced frequency, in order to re-determine whether the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the second set temperature within a continuous third set time period.

[0073] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 33, determining whether the continuous time t5 is sufficient to detect the temperature T in the middle of the evaporator. sm ≤Temperature T3: If the temperature T in the middle of the evaporator is detected over a continuous time t5. sm If the temperature is ≤T3, the compressor stops to defrost; otherwise, return to step 32.

[0074] The value of time t5 ranges from 2 min to 6 min (e.g., t5 is 3 min). The value of temperature T3 ranges from -5℃ to 5℃ (e.g., T3 is -1℃).

[0075] It should be noted that in step 3, detecting a certain condition at a continuous time t (such as time t2, time t3, or time t5) means that a certain condition is consistently met within the time t (such as time t2, time t3, or time t5) counting backwards from the current moment without interruption.

[0076] In step S150, if it is determined that the refrigerant circulation of the air conditioner is abnormal, the compressor is controlled to operate at a reduced frequency or stop to defrost based on the temperature in the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor, so as to prevent the refrigerant system of the air conditioner from fluctuating due to excessive adjustment.

[0077] The present invention provides a control scheme to prevent frost buildup on the indoor heat exchanger of an air conditioner. By installing a pressure sensor on the compressor suction pipe, the compressor's suction superheat can be accurately detected. Then, after the air conditioner is turned on for cooling, the refrigerant circulation rate is determined based on the evaporator's mid-temperature and the compressor's suction superheat. Based on the determination result, the compressor frequency is limited in stages, achieving different levels of control such as reducing the compressor frequency and stopping for defrosting, preventing excessively rapid adjustments that could cause fluctuations in the air conditioner's refrigerant system operation. In this way, regardless of whether the refrigerant level is normal or insufficient, timely evaporator anti-freezing or defrosting can be performed, preventing persistent frost or ice buildup on the evaporator surface. This ensures the unit operates at its maximum heat exchange capacity, guarantees reliable operation, and prevents abnormalities such as frost blocking the drain outlet causing leaks, compressor wear due to liquid return during suction, or even refrigerant system failure.

[0078] In some embodiments, step S150, when it is determined that the refrigerant circulation volume of the air conditioner is abnormal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor, including: a first control logic for controlling the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is abnormal.

[0079] The following is combined with Figure 6 The diagram shows an embodiment of the flow path of the first control logic for controlling the compressor to operate at a reduced frequency or to stop defrosting when the refrigerant circulation of the air conditioner is abnormal. The diagram further illustrates the specific process of the first control logic for controlling the compressor to operate at a reduced frequency or to stop defrosting when the refrigerant circulation of the air conditioner is abnormal in step S150, including steps S610 to S640.

[0080] Step S610: For the temperature of the middle part of the inner pipe of the air conditioner and the suction saturation temperature of the compressor obtained every sixth set time interval, the temperature of the middle part of the inner pipe of the air conditioner obtained in two consecutive intervals is recorded as the i-th temperature of the middle part of the inner pipe and the (i+1)-th temperature of the middle part of the inner pipe; and the suction saturation temperature of the compressor obtained in two consecutive intervals is recorded as the i-th suction saturation temperature and the (i+1)-th suction saturation temperature; where i is the number of the previous acquisition in two consecutive acquisitions and i is a positive integer, and i+1 is the number of the next acquisition in two consecutive acquisitions.

[0081] Step S620: Determine whether the following conditions are met: the (i+1)th inner tube mid-section temperature obtained for a first set number of consecutive cycles is less than the ith inner tube mid-section temperature; the (i+1)th intake saturation temperature is less than the ith intake saturation temperature; and the difference between the (i+1)th inner tube mid-section temperature and the ith inner tube mid-section temperature is greater than or equal to a second set temperature threshold. Here, the first set number of cycles is, for example, m cycles, and the second set temperature threshold is, for example, temperature ΔT2.

[0082] If the conditions are not met in step S630, then the compressor is controlled to operate at the frequency set in the refrigeration mode, that is, the compressor is controlled to operate normally.

[0083] Step S640: If the condition is met, control the compressor to operate at the frequency set in the refrigeration mode and prohibit the compressor from increasing its frequency.

[0084] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: Step 4, the anti-freezing and defrosting control process when the refrigerant circulation of the unit is insufficient, see steps 41, 42, 43, 44, and 43. Specifically, in step 41, the temperature T at the center of the evaporator is detected every time interval t6. smand the compressor's intake saturation temperature T sat The temperature T in the middle of the evaporator was measured in the previous test. sm and the compressor's intake saturation temperature T sat The temperature T in the middle of the evaporator was used respectively. sm(i) and the compressor's intake saturation temperature T sat1(i) This indicates that the temperature T in the middle of the evaporator was measured in the last test. sm and the compressor's intake saturation temperature T sat The temperature T in the middle of the evaporator was used respectively. sm(i+1) and the compressor's intake saturation temperature T sat(i+1) This indicates that step 42 will then be executed. The value of time t6 ranges from 5 min to 10 min; for example, time t6 can be set to 6 min.

[0085] Step 42: Determine whether the current detected evaporator mid-temperature T is met after m consecutive detections. sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) ≥Temperature ΔT2: If the temperature T in the middle of the evaporator is detected m times consecutively, then... sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) If the temperature is ≥ ΔT2, the compressor is not allowed to increase its frequency, and then step 43 is executed; otherwise, the air conditioner is controlled to operate normally.

[0086] The value of m ranges from 1 to 5, such as m being 3. The value of temperature ΔT2 ranges from -5℃ to -1℃, such as temperature ΔT2 being -2℃.

[0087] In some embodiments, step S150, when it is determined that the refrigerant circulation volume of the air conditioner is abnormal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor. It further includes: a second control logic for controlling the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is abnormal.

[0088] The following is combined with Figure 7 The diagram shows an embodiment of the flow path of the second control logic for controlling the compressor to operate at a reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is abnormal. The diagram further illustrates the specific process of the second control logic for controlling the compressor to operate at a reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is abnormal in step S150, including steps S710 to S730.

[0089] Step S710: After controlling the compressor to operate at the frequency set in the cooling mode and prohibiting the compressor from increasing its frequency, determine whether the following conditions are met: the (i+1)th inner tube mid-section temperature obtained for a second set number of consecutive cycles is lower than the ith inner tube mid-section temperature; the (i+1)th suction saturation temperature is lower than the ith suction saturation temperature; and the difference between the (i+1)th inner tube mid-section temperature and the ith inner tube mid-section temperature is greater than or equal to a second set temperature threshold. The second set number of cycles is greater than the first set number of cycles. The second set number of cycles is, for example, n times, and the second set temperature threshold is, for example, temperature ΔT2.

[0090] If the conditions are not met in step S720, then while controlling the compressor to operate at the frequency set in the cooling mode and prohibiting the compressor from increasing its frequency, return to re-determine whether the following conditions are met: the temperature of the (i+1)th inner tube middle section obtained for the first set number of consecutive cycles is less than the temperature of the i-th inner tube middle section, the (i+1)th suction saturation temperature is less than the i-th suction saturation temperature, and the difference between the temperature of the (i+1)th inner tube middle section and the temperature of the i-th inner tube middle section is greater than or equal to the second set temperature threshold.

[0091] Step S730: If satisfied, control the compressor to operate at a reduced frequency; wherein, controlling the compressor to operate at a reduced frequency includes: controlling the compressor frequency to decrease by a second set frequency every seventh set time interval, and controlling the compressor to operate at the reduced frequency. Wherein, the seventh set time is such as time t7, and the second set frequency is such as frequency Y Hz.

[0092] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 43, determining whether the current detected evaporator mid-section temperature T is satisfied with n consecutive detections. sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) ≥Temperature ΔT2: If the temperature T in the middle of the evaporator is detected n times consecutively, that is, if the temperature T in the middle of the evaporator is detected in the current detection, then...sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) If the temperature is greater than or equal to ΔT2, the compressor will reduce the frequency by YHz every time interval t7. The frequency reduction can only be performed once within time t7, after which step 44 or step 45 will be executed; otherwise, return to step 42.

[0093] Wherein, n ranges from 2 to 6, e.g., n = 4. Temperature ΔT2 ranges from -5℃ to -1℃, e.g., ΔT2 = -2℃. Time t7 ranges from 1 min to 10 min, e.g., t7 = 5 min. Frequency Y ranges from 5 Hz to 15 Hz, e.g., 10 Hz.

[0094] In some embodiments, step S150, when it is determined that the refrigerant circulation volume of the air conditioner is abnormal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor. It further includes a third control logic for controlling the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is abnormal.

[0095] The following is combined Figure 8 The diagram shows an embodiment of the flow path of the third control logic in the method of the present invention, which controls the compressor to operate at a reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is abnormal. The diagram further illustrates the specific process of the third control logic in step S150, which controls the compressor to operate at a reduced frequency or to stop and defrost when the refrigerant circulation of the air conditioner is abnormal, including steps S810 to S830.

[0096] Step S810: After controlling the compressor to operate at a reduced frequency, execute a first judgment logic and / or execute a second judgment logic. The first judgment logic determines whether the following conditions are met: the temperature at the middle of the (i+1)th inner tube is less than the temperature at the middle of the ith inner tube, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner tube temperature and the ith inner tube temperature is greater than or equal to a second set temperature threshold. The second judgment logic determines whether the temperature at the middle of the (i+1)th inner tube is less than the temperature at the ith inner tube, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner tube temperature and the ith inner tube temperature is less than a second set temperature threshold. The third set number of times is greater than the second set number of times. For example, the third set number of times is p times, and the fourth set number of times is q times.

[0097] Step S820: If the judgment result of the first judgment logic is not satisfied, then under the condition of controlling the compressor to operate at a reduced frequency, return to re-determine whether the following conditions are met: the temperature of the (i+1)th inner tube middle section obtained for the second set number of consecutive times is less than the temperature of the i-th inner tube middle section, the (i+1)th suction saturation temperature is less than the i-th suction saturation temperature, and the difference between the temperature of the (i+1)th inner tube middle section and the temperature of the i-th inner tube middle section is greater than or equal to the second set temperature threshold.

[0098] Step S830: If the judgment result of the first judgment logic is satisfied, then control the compressor to stop for defrosting.

[0099] Step S840: If the judgment result of the second judgment logic is not satisfied, then the first judgment logic is executed while controlling the compressor to operate at a reduced frequency.

[0100] Step S850: If the judgment result of the second judgment logic is satisfied, then control the compressor to stop for defrosting.

[0101] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 44, determining whether the current detected evaporator mid-temperature T is satisfied with being detected p times consecutively. sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) The current detected temperature T in the middle of the evaporator sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) ≥Temperature ΔT2: If the temperature T in the middle of the evaporator is detected p times consecutively, then... sm(i+1) <Previously detected evaporator mid-section temperature Tsm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) The current detected temperature T in the middle of the evaporator sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) If the temperature is ≥ ΔT2, then the compressor will stop for defrosting; otherwise, return to step 43.

[0102] The value of p ranges from 2 to 6, such as p = 5.

[0103] Step 45: Determine whether the current detected evaporator mid-temperature T is satisfied with q consecutive detections. sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) <Temperature ΔT2: If the temperature T in the middle of the evaporator is detected q times consecutively, then... sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) If the temperature is less than ΔT2, the compressor will stop for defrosting; otherwise, proceed to step 44.

[0104] The value of q ranges from 1 to 5, such as q = 3. The value of temperature ΔT2 ranges from -5℃ to -1℃, such as temperature ΔT2 = -2℃.

[0105] It should be noted that in step 4, detecting a certain condition m times (or n times or p times or q times) means counting back m times (or n times or p times or q times) from the current time, and the condition is met each time. If the condition is not met even once, the count is reset to zero.

[0106] The technical solution of this embodiment detects the temperature at the center of the evaporator and the pressure on the compressor suction pipe after the air conditioner is turned on for cooling. Based on the temperature at the center of the evaporator and the pressure on the compressor suction pipe, it determines whether the refrigerant circulation is normal. When the refrigerant circulation is normal, the compressor frequency is controlled based on the temperature at the center of the evaporator. When the refrigerant circulation is abnormal, the compressor frequency is controlled based on the temperature at the center of the evaporator and the pressure on the compressor suction pipe. This achieves different levels of control, such as reducing the compressor frequency and stopping for defrosting. Thus, by combining the temperature at the center of the evaporator and the pressure on the compressor suction pipe, different levels of control, such as reducing the compressor frequency and stopping for defrosting, are achieved. Regardless of whether the refrigerant quantity of the unit is normal or insufficient, the evaporator can be prevented from freezing or defrosted in a timely manner, improving the reliability and safety of the air conditioner operation.

[0107] According to an embodiment of the present invention, a control device for an air conditioner corresponding to the control method for an air conditioner is also provided. See also Figure 9 The diagram shows a structural schematic of an embodiment of the device of the present invention. The air conditioner includes a compressor and an indoor heat exchanger; specifically, Figure 10 This is a schematic diagram of the structure of one embodiment of an air conditioner. In cooling mode, as... Figure 10 The air conditioner shown includes: a compressor, a condenser, an evaporator, a four-way valve, and an electronic expansion valve. The compressor's discharge port is connected to the first port of the four-way valve; the second port of the four-way valve, after passing through the condenser, the electronic expansion valve, and the evaporator, is connected to the fourth port of the four-way valve; the third port of the four-way valve is connected to the compressor's suction port. A discharge temperature sensor is installed on the pipeline between the compressor's discharge port and the first port of the four-way valve; a pressure sensor (i.e., a pressure sensor is installed on the compressor's suction pipe) is installed on the pipeline between the third port of the four-way valve and the compressor's suction port; an outdoor ambient temperature sensor and a temperature sensor in the middle of the condenser are installed at the condenser; an indoor ambient temperature sensor and a temperature sensor in the middle of the evaporator are installed at the evaporator; a shut-off valve is installed on the pipeline where the evaporator inlet is located; and another shut-off valve is installed on the pipeline where the evaporator outlet is located. Preferably, as shown... Figure 10 The air conditioner shown also includes filters, and there can be more than two filters. For example, a filter is installed on the pipeline between another shut-off valve on the pipeline where the evaporator outlet is located and the fourth valve port of the four-way valve; a filter is installed on the pipeline between the condenser outlet and the inlet of the electronic expansion valve; a filter is installed between a shut-off valve on the pipeline where the electronic expansion valve outlet is located and the evaporator inlet, and so on.

[0108] In the solution of the present invention, such as Figure 9 As shown, the control device of the air conditioner includes: an acquisition unit 102 and a control unit 104.

[0109] The acquisition unit 102 is configured to acquire the mid-temperature of the indoor heat exchanger after the air conditioner has been turned on and running in cooling mode for a first set time, and record it as the mid-temperature of the inner pipe of the air conditioner, such as the mid-temperature of the evaporator T. sm And obtain the pressure on the pipeline where the compressor's suction port is located, and record it as the compressor's suction pressure, such as the unit's low-pressure P. S The specific functions and processing of the acquisition unit 102 are described in step S110. The first set time is, for example, time t1. Specifically, Figure 11 This is a flow path diagram of an embodiment of a control method for preventing frost buildup on the indoor heat exchanger in an air conditioner. Figure 11 The control method shown for preventing frost buildup on the indoor heat exchanger in an air conditioner includes: Step 1, turning on the air conditioner in cooling mode and detecting the temperature T in the middle of the evaporator. sm Unit low pressure P S Low pressure corresponds to saturation temperature T sat Then proceed to step 2. For example... Figure 10 The unit shown is equipped with a temperature sensor in the middle of the evaporator and a pressure sensor located on the compressor suction pipe. The temperature sensor in the middle of the evaporator can be used to detect the temperature T in the middle of the evaporator. sm The low-pressure P of the unit can be detected using a pressure sensor located on the compressor suction pipe. S .

[0110] The control unit 104 is configured to determine, based on the suction pressure of the compressor, a saturation temperature corresponding to the suction pressure of the compressor, denoted as the suction saturation temperature of the compressor, such as a saturation temperature T corresponding to low pressure. sat The specific functions and processing of the control unit 104 are described in step S120. Specifically, as follows... Figure 11 The control method for preventing frost buildup on the indoor heat exchanger in an air conditioner, as shown, further includes: in step 1, a pressure sensor located on the compressor suction pipe can detect the low-pressure P of the unit. S According to the low pressure P of the unit S The compressor's suction saturation temperature T corresponding to the compressor's low-pressure setting can be calculated. sat .

[0111] The control unit 104 is further configured to, when the air conditioner has been running in cooling mode for a first set time, determine whether the refrigerant circulation of the air conditioner is normal based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor. The specific functions and processing of this control unit 104 are further described in step S130.

[0112] In some embodiments, the control unit 104 determines whether the refrigerant circulation of the air conditioner is normal based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor, including:

[0113] The control unit 104 is further configured to determine whether the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is less than or equal to a first set temperature difference threshold, and to determine whether the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the suction saturation temperature of the compressor. The specific functions and processing of this control unit 104 are further described in step S210. The first set temperature difference threshold is, for example, temperature ΔT1. Specifically, as... Figure 11 The control method for preventing frost buildup on the indoor heat exchanger in an air conditioner, as shown, further includes: Step 2, after the unit has been running for t1, performing the judgments in steps 21, 22, and 23, and then selectively performing either step 3 or step 4 based on the judgment results. The value of time t1 ranges from 30 min to 120 min, for example, t1 can be set to 60 min.

[0114] The control unit 104 is further configured to determine that the refrigerant circulation of the air conditioner is normal if the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is less than or equal to a first set temperature difference threshold. The specific functions and processing of this control unit 104 are further described in step S220. Specifically, as follows... Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 21, if | the compressor's suction saturation temperature T sat -Evaporator mid-temperature T sm If the temperature ΔT1 is less than or equal to the unit's temperature, then the refrigerant circulation is considered normal, and step 3 is then executed. The temperature ΔT1 ranges from 2℃ to 6℃; for example, if ΔT1 is set to 5℃.

[0115] The control unit 104 is further configured to determine that the refrigerant circulation of the air conditioner is normal if the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is greater than a first set temperature difference threshold, and the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the suction saturation temperature of the compressor. The specific functions and processing of this control unit 104 are further described in step S230. Specifically, as... Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 22, if | the compressor's suction saturation temperature T sat -Evaporator mid-temperature T sm |>Temperature ΔT1 and temperature T in the middle of the evaporator sm ≤Compressor suction saturation temperature T satIf the refrigerant circulation rate of the unit is normal, then step 3 is executed. The temperature ΔT1 ranges from 2℃ to 6℃; for example, if ΔT1 is set to 5℃.

[0116] The control unit 104 is further configured to determine that the refrigerant circulation of the air conditioner is abnormal if the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is greater than a first set temperature difference threshold, and the temperature at the middle of the inner pipe of the air conditioner is greater than the suction saturation temperature of the compressor. The specific functions and processing of this control unit 104 are further described in step S240. Specifically, as... Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 23, if | the compressor's suction saturation temperature T sat -Evaporator mid-temperature T sm |>Temperature ΔT1 and temperature T in the middle of the evaporator sm >Compressor suction saturation temperature T sat If the refrigerant circulation is insufficient, then step 4 is executed. The temperature ΔT1 ranges from 2℃ to 6℃; for example, if ΔT1 is set to 5℃.

[0117] The control unit 104 is further configured to, if it is determined that the refrigerant circulation of the air conditioner is normal, control the compressor to operate at a reduced frequency or stop for defrosting based on the temperature in the middle of the air conditioner's inner pipe, in order to prevent fluctuations in the operating status of the air conditioner's refrigerant system caused by excessively rapid adjustments. The specific functions and processing of this control unit 104 are further described in step S140.

[0118] In some embodiments, the control unit 104, upon determining that the refrigerant circulation volume of the air conditioner is normal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the air conditioner's inner pipe. This includes: a first control logic for controlling the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is normal, as detailed below:

[0119] The control unit 104 is further configured to determine whether the temperature at the middle of the inner pipe of the air conditioner is less than or equal to a first set temperature within a continuous second set time period. The specific functions and processing of the control unit 104 are further described in step S310. The second set time is, for example, time t2, and the first set temperature is, for example, temperature T1.

[0120] The control unit 104 is further configured to, if it is determined that the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the first set temperature within a continuous second set time period, control the compressor to operate at a frequency set in the cooling mode, that is, control the compressor to operate normally. The specific functions and processing of this control unit 104 are further described in step S320.

[0121] The control unit 104 is further configured to, if it is determined that the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the first set temperature within a second set time period, control the compressor to operate at a frequency set in the cooling mode and prohibit the compressor from increasing its frequency. The specific functions and processing of this control unit 104 are further described in step S330.

[0122] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: Step 3, the anti-freezing and defrosting control process when the refrigerant circulation rate of the unit is normal, see steps 31, 32, and 33. Specifically, step 31 involves determining whether the temperature T in the middle of the evaporator is detected continuously for time t2. sm ≤Temperature T1: If so, the temperature T in the middle of the evaporator is detected continuously over time t2. sm If the temperature is ≤T1, the compressor is not allowed to increase its frequency, and then step 32 is executed; otherwise, the air conditioner operates normally. The value of time t2 ranges from 2 min to 6 min, for example, t2 is set to 3 min. The value of temperature T1 ranges from 2℃ to 6℃, for example, temperature T1 is set to 4℃.

[0123] In some embodiments, the control unit 104, upon determining that the refrigerant circulation volume of the air conditioner is normal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the air conditioner's inner pipe. The control unit further includes a second control logic that controls the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is normal, as detailed below:

[0124] The control unit 104 is further configured to, after controlling the compressor to operate at a frequency programmed in cooling mode and prohibiting the compressor from increasing its frequency, determine whether the temperature at the middle of the air conditioner's inner pipe is less than or equal to a second set temperature within a third consecutive set time period; wherein the second set temperature is less than the first set temperature. The specific functions and processing of this control unit 104 are further described in step S410. The third set time is, for example, time t3, and the second set temperature is, for example, temperature T2.

[0125] The control unit 104 is further configured to, if it is determined that the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the second set temperature within a third consecutive set time period, return to the previous state while controlling the compressor to operate at the frequency set in the cooling mode and prohibiting the compressor from increasing its frequency, to re-determine whether the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the first set temperature within a second consecutive set time period. The specific functions and processing of this control unit 104 are further described in step S420.

[0126] The control unit 104 is further configured to control the compressor to operate at a reduced frequency if it is determined that the temperature at the middle of the inner pipe of the air conditioner is less than or equal to a second set temperature within a third consecutive set time period. Controlling the compressor to operate at a reduced frequency includes: controlling the compressor frequency to decrease by a first set frequency every fourth set time period, and controlling the compressor to operate at the reduced frequency. The specific functions and processing of the control unit 104 are further described in step S430. The fourth set time period is, for example, time t4, and the first set frequency is, for example, frequency X Hz.

[0127] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 32, determining whether the temperature T in the middle of the evaporator is detected continuously for time t3. sm ≤Temperature T2: If so, the temperature T in the middle of the evaporator is detected over a continuous time t3. sm When the temperature is ≤ T2, the compressor reduces the frequency by X Hz every time t4. The frequency reduction can only be performed once within time t4, and then step 33 is executed; otherwise, return to step 31.

[0128] The values ​​for time t3 range from 2 min to 6 min, such as 3 min. The values ​​for temperature T2 range from 0 to 5℃, such as 2℃. The values ​​for time t4 range from 1 min to 10 min, such as 5 min. The values ​​for frequency X range from 5 Hz to 15 Hz, such as 10 Hz.

[0129] In some embodiments, the control unit 104, upon determining that the refrigerant circulation volume of the air conditioner is normal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the air conditioner's inner pipe. The control unit further includes a third control logic for controlling the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is normal, as detailed below:

[0130] The control unit 104 is further configured to, after controlling the compressor to operate at a reduced frequency, determine whether the temperature at the middle of the air conditioner's inner pipe is less than or equal to a third set temperature within a continuous fifth set time period; wherein the third set temperature is less than the second set temperature. The specific functions and processing of this control unit 104 are further described in step S510. The fifth set time is, for example, time t5, and the third set temperature is, for example, temperature T3.

[0131] The control unit 104 is further configured to control the compressor to stop defrosting if it is determined that the temperature at the middle of the inner pipe of the air conditioner is less than or equal to a third set temperature within a fifth consecutive set time period. The specific functions and processing of the control unit 104 are further described in step S520.

[0132] The control unit 104 is further configured to, if it is determined that the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the third set temperature within a continuous fifth set time period, return to the previous state while controlling the compressor to operate at a reduced frequency, to re-determine whether the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the second set temperature within a continuous third set time period. The specific functions and processing of this control unit 104 are further described in step S530.

[0133] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 33, determining whether the continuous time t5 is sufficient to detect the temperature T in the middle of the evaporator. sm ≤Temperature T3: If the temperature T in the middle of the evaporator is detected over a continuous time t5. sm If the temperature is ≤T3, the compressor stops to defrost; otherwise, return to step 32.

[0134] The value of time t5 ranges from 2 min to 6 min (e.g., t5 is 3 min). The value of temperature T3 ranges from -5℃ to 5℃ (e.g., T3 is -1℃).

[0135] It should be noted that in step 3, detecting a certain condition at a continuous time t (such as time t2, time t3, or time t5) means that a certain condition is consistently met within the time t (such as time t2, time t3, or time t5) counting backwards from the current moment without interruption.

[0136] The control unit 104 is further configured to, if it is determined that the refrigerant circulation volume of the air conditioner is abnormal, control the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor, in order to prevent excessively rapid adjustments from causing fluctuations in the operating state of the air conditioner's refrigerant system. The specific functions and processing of this control unit 104 are further described in step S150.

[0137] The present invention provides a control scheme to prevent frost buildup on the indoor heat exchanger of an air conditioner. By installing a pressure sensor on the compressor suction pipe, the compressor's suction superheat can be accurately detected. Then, after the air conditioner is turned on for cooling, the refrigerant circulation rate is determined based on the evaporator's mid-temperature and the compressor's suction superheat. Based on the determination result, the compressor frequency is limited in stages, achieving different levels of control such as reducing the compressor frequency and stopping for defrosting, preventing excessively rapid adjustments that could cause fluctuations in the air conditioner's refrigerant system operation. In this way, regardless of whether the refrigerant level is normal or insufficient, timely evaporator anti-freezing or defrosting can be performed, preventing persistent frost or ice buildup on the evaporator surface. This ensures the unit operates at its maximum heat exchange capacity, guarantees reliable operation, and prevents abnormalities such as frost blocking the drain outlet causing leaks, compressor wear due to liquid return during suction, or even refrigerant system failure.

[0138] In some embodiments, the control unit 104, upon determining that the refrigerant circulation volume of the air conditioner is abnormal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor. This includes: a first control logic for controlling the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is abnormal, as follows:

[0139] The control unit 104 is further configured to, for the temperature of the middle part of the inner pipe of the air conditioner and the suction saturation temperature of the compressor acquired at six predetermined intervals, record the temperature of the middle part of the inner pipe of the air conditioner acquired in two consecutive intervals as the i-th temperature of the middle part of the inner pipe and the (i+1)-th temperature of the middle part of the inner pipe; and record the suction saturation temperature of the compressor acquired in two consecutive intervals as the i-th suction saturation temperature and the (i+1)-th suction saturation temperature; where i is the number of the previous acquisition in two consecutive acquisitions and i is a positive integer, and i+1 is the number of the subsequent acquisition in two consecutive acquisitions. The specific functions and processing of this control unit 104 are further described in step S610.

[0140] The control unit 104 is further configured to determine whether the following conditions are met: the (i+1)th inner tube mid-section temperature is less than the ith inner tube mid-section temperature, the (i+1)th intake saturation temperature is less than the ith intake saturation temperature, and the difference between the (i+1)th inner tube mid-section temperature and the ith inner tube mid-section temperature is greater than or equal to a second set temperature threshold. The specific functions and processing of this control unit 104 are further described in step S620. The first set number of times is, for example, m times, and the second set temperature threshold is, for example, temperature ΔT2.

[0141] The control unit 104 is further configured to, if the condition is not met, control the compressor to operate at a frequency set in the refrigeration mode, i.e., control the compressor to operate normally. The specific functions and processing of the control unit 104 are further described in step S630.

[0142] The control unit 104 is further configured to, if satisfied, control the compressor to operate at the frequency set in the cooling mode and prohibit the compressor from increasing its frequency. The specific functions and processing of the control unit 104 are further described in step S640.

[0143] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: Step 4, the anti-freezing and defrosting control process when the refrigerant circulation of the unit is insufficient, see steps 41, 42, 43, 44, and 43. Specifically, in step 41, the temperature T at the center of the evaporator is detected every time interval t6. sm and the compressor's intake saturation temperature T sat The temperature T in the middle of the evaporator was measured in the previous test. sm and the compressor's intake saturation temperature T sat The temperature T in the middle of the evaporator was used respectively. sm(i) and the compressor's intake saturation temperature T sat1(i) This indicates that the temperature T in the middle of the evaporator was measured in the last test. sm and the compressor's intake saturation temperature T sat The temperature T in the middle of the evaporator was used respectively. sm(i+1) and the compressor's intake saturation temperature T sat(i+1) This indicates that step 42 will then be executed. The value of time t6 ranges from 5 min to 10 min; for example, time t6 can be set to 6 min.

[0144] Step 42: Determine whether the current detected evaporator mid-temperature T is met after m consecutive detections. sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) ≥Temperature ΔT2: If the temperature T in the middle of the evaporator is detected m times consecutively, then... sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i)And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) If the temperature is ≥ ΔT2, the compressor is not allowed to increase its frequency, and then step 43 is executed; otherwise, the air conditioner is controlled to operate normally.

[0145] The value of m ranges from 1 to 5, such as m being 3. The value of temperature ΔT2 ranges from -5℃ to -1℃, such as temperature ΔT2 being -2℃.

[0146] In some embodiments, the control unit 104, upon determining that the refrigerant circulation volume of the air conditioner is abnormal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor. The control unit further includes a second control logic for controlling the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is abnormal, as follows:

[0147] The control unit 104 is further configured to, after controlling the compressor to operate at a frequency programmed in refrigeration mode and prohibiting the compressor from increasing its frequency, determine whether the following conditions are met: the (i+1)th inner tube mid-section temperature obtained for a second set number of consecutive cycles is lower than the ith inner tube mid-section temperature; the (i+1)th suction saturation temperature is lower than the ith suction saturation temperature; and the difference between the (i+1)th inner tube mid-section temperature and the ith inner tube mid-section temperature is greater than or equal to a second set temperature threshold. The second set number of cycles is greater than the first set number of cycles. The specific function and processing of this control unit 104 are further described in step S710. The second set number of cycles is, for example, n times, and the second set temperature threshold is, for example, temperature ΔT2.

[0148] The control unit 104 is further configured to, if the conditions are not met, return to the previous state while controlling the compressor to operate at the frequency set in the cooling mode and prohibiting the compressor from increasing its frequency, in order to re-determine whether the following conditions are met: the (i+1)th inner tube mid-section temperature is less than the ith inner tube mid-section temperature, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner tube mid-section temperature and the ith inner tube mid-section temperature is greater than or equal to a second set temperature threshold. The specific functions and processing of this control unit 104 are further described in step S720.

[0149] The control unit 104 is further configured to control the compressor to operate at a reduced frequency if the specified conditions are met. Controlling the compressor to operate at a reduced frequency includes: controlling the compressor's frequency to decrease by a second set frequency every seventh set time interval, and controlling the compressor to operate at the reduced frequency. The specific functions and processing of the control unit 104 are further described in step S730. The seventh set time is, for example, time t7, and the second set frequency is, for example, frequency Y Hz.

[0150] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 43, determining whether the current detected evaporator mid-section temperature T is satisfied with n consecutive detections. sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) ≥Temperature ΔT2: If the temperature T in the middle of the evaporator is detected n times consecutively, that is, if the temperature T in the middle of the evaporator is detected in the current detection, then... sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) If the temperature is greater than or equal to ΔT2, the compressor will reduce the frequency by YHz every time interval t7. The frequency reduction can only be performed once within time t7, after which step 44 or step 45 will be executed; otherwise, return to step 42.

[0151] Wherein, n ranges from 2 to 6, e.g., n = 4. Temperature ΔT2 ranges from -5℃ to -1℃, e.g., ΔT2 = -2℃. Time t7 ranges from 1 min to 10 min, e.g., t7 = 5 min. Frequency Y ranges from 5 Hz to 15 Hz, e.g., 10 Hz.

[0152] In some embodiments, the control unit 104, upon determining that the refrigerant circulation volume of the air conditioner is abnormal, controls the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor. The control unit further includes a third control logic for controlling the compressor to operate at a reduced frequency or stop for defrosting when the refrigerant circulation volume of the air conditioner is abnormal, as detailed below:

[0153] The control unit 104 is further configured to execute a first judgment logic and / or a second judgment logic after controlling the compressor to operate at a reduced frequency. The first judgment logic determines whether the following conditions are met: the (i+1)th inner tube mid-section temperature obtained for a third consecutive set number of times is less than the i-th inner tube mid-section temperature, the (i+1)th suction saturation temperature is less than the i-th suction saturation temperature, and the difference between the (i+1)th inner tube mid-section temperature and the i-th inner tube mid-section temperature is greater than or equal to a second set temperature threshold. The second judgment logic determines whether the following conditions are met: the (i+1)th inner tube mid-section temperature obtained for a fourth consecutive set number of times is less than the i-th inner tube mid-section temperature, the (i+1)th suction saturation temperature is less than the i-th suction saturation temperature, and the difference between the (i+1)th inner tube mid-section temperature and the i-th inner tube mid-section temperature is less than the second set temperature threshold. The third set number of times is greater than the second set number of times. The specific functions and processing of the control unit 104 are further described in step S810. The third set number of times is, for example, p times, and the fourth set number of times is, for example, q times.

[0154] The control unit 104 is further configured to, if the judgment result of the first judgment logic is not satisfied, return while controlling the compressor to operate at a reduced frequency, to re-determine whether the following conditions are met: the temperature of the (i+1)th inner tube middle section is less than the temperature of the ith inner tube middle section, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner tube middle section temperature and the temperature of the ith inner tube middle section is greater than or equal to a second set temperature threshold. The specific functions and processing of this control unit 104 are further described in step S820.

[0155] The control unit 104 is further configured to control the compressor to stop for defrosting if the judgment result of the first judgment logic is satisfied. The specific functions and processing of the control unit 104 are further described in step S830.

[0156] The control unit 104 is further configured to execute the first judgment logic if the judgment result of the second judgment logic is not satisfied, while controlling the compressor to operate at a reduced frequency. The specific functions and processing of the control unit 104 are further described in step S840.

[0157] The control unit 104 is further configured to control the compressor to stop for defrosting if the judgment result of the second judgment logic is satisfied. The specific functions and processing of the control unit 104 are further described in step S850.

[0158] Specifically, such as Figure 11 The control method for preventing frost formation on the indoor heat exchanger in an air conditioner, as shown, further includes: step 44, determining whether the current detected evaporator mid-temperature T is satisfied with being detected p times consecutively. sm(i+1) <Previously detected evaporator mid-section temperature T sm(i)The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) The current detected temperature T in the middle of the evaporator sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) ≥Temperature ΔT2: If the temperature T in the middle of the evaporator is detected p times consecutively, then... sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) The current detected temperature T in the middle of the evaporator sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) If the temperature is ≥ ΔT2, then the compressor will stop for defrosting; otherwise, return to step 43.

[0159] The value of p ranges from 2 to 6, such as p = 5.

[0160] Step 45: Determine whether the current detected evaporator mid-temperature T is satisfied with q consecutive detections. sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) <Temperature ΔT2: If the temperature T in the middle of the evaporator is detected q times consecutively, then... sm(i+1) <Previously detected evaporator mid-section temperature T sm(i) The compressor's suction saturation temperature T detected at the last time. sat(i+1) <Previously detected compressor intake saturation temperature T sat(i) And the temperature T in the middle of the evaporator detected in the last time sm(i+1) -Previously detected evaporator mid-section temperature T sm(i) If the temperature is less than ΔT2, the compressor will stop for defrosting; otherwise, proceed to step 44.

[0161] The value of q ranges from 1 to 5, such as q = 3. The value of temperature ΔT2 ranges from -5℃ to -1℃, such as temperature ΔT2 = -2℃.

[0162] It should be noted that in step 4, detecting a certain condition m times (or n times or p times or q times) means counting back m times (or n times or p times or q times) from the current time, and the condition is met each time. If the condition is not met even once, the count is reset to zero.

[0163] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0164] By employing the technical solution of this invention, after the air conditioner is turned on for cooling, the temperature in the middle of the evaporator and the pressure on the compressor suction pipe are detected. Based on the temperature in the middle of the evaporator and the pressure on the compressor suction pipe, it is determined whether the refrigerant circulation is normal. When the refrigerant circulation is normal, the compressor frequency is controlled according to the temperature in the middle of the evaporator. When the refrigerant circulation is abnormal, the compressor frequency is controlled according to the temperature in the middle of the evaporator and the pressure on the compressor suction pipe. This achieves different levels of control, such as reducing the compressor frequency and stopping for defrosting, ensuring that the unit can achieve maximum heat exchange capacity and guarantee reliable operation of the unit.

[0165] According to an embodiment of the present invention, an air conditioner corresponding to a control device for an air conditioner is also provided. This air conditioner may include the control device for an air conditioner described above.

[0166] Since the processing and functions implemented by the air conditioner in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned devices, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0167] By employing the technical solution of this invention, after the air conditioner is turned on for cooling, the temperature in the middle of the evaporator and the pressure on the compressor suction pipe are detected. Based on the temperature in the middle of the evaporator and the pressure on the compressor suction pipe, it is determined whether the refrigerant circulation is normal. When the refrigerant circulation is normal, the compressor frequency is controlled according to the temperature in the middle of the evaporator. When the refrigerant circulation is abnormal, the compressor frequency is controlled according to the temperature in the middle of the evaporator and the pressure on the compressor suction pipe. This achieves different levels of control, such as reducing the compressor frequency and stopping for defrosting, to prevent persistent frost or ice formation on the evaporator surface and ensure that the unit operates at its maximum heat exchange capacity.

[0168] According to an embodiment of the present invention, a storage medium corresponding to a control method for an air conditioner is also provided, the storage medium including a stored program, wherein the program controls the device where the storage medium is located to execute the control method for the air conditioner described above when it is executed.

[0169] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0170] By employing the technical solution of this invention, after the air conditioner is turned on for cooling, the temperature in the middle of the evaporator and the pressure on the compressor suction pipe are detected. Based on the temperature in the middle of the evaporator and the pressure on the compressor suction pipe, it is determined whether the refrigerant circulation is normal. When the refrigerant circulation is normal, the compressor frequency is controlled according to the temperature in the middle of the evaporator. When the refrigerant circulation is abnormal, the compressor frequency is controlled according to the temperature in the middle of the evaporator and the pressure on the compressor suction pipe. This achieves different levels of control, such as reducing the compressor frequency and stopping the machine for defrosting, to prevent abnormalities such as frost blocking the drain outlet and causing water leakage, compressor wear due to liquid return during air intake, or even paralysis of the air conditioner's refrigerant system.

[0171] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0172] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A control method for an air conditioner, characterized in that, The air conditioner has a compressor and an indoor heat exchanger; The control method for the air conditioner includes: After the air conditioner is turned on and running in cooling mode for a first set time, the temperature at the middle of the indoor heat exchanger is obtained and recorded as the temperature at the middle of the inner pipe of the air conditioner; and the pressure on the pipe where the compressor's suction port is located is obtained and recorded as the suction pressure of the compressor. Based on the suction pressure of the compressor, determine the saturation temperature corresponding to the suction pressure of the compressor, and record it as the suction saturation temperature of the compressor; Based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor, determine whether the refrigerant circulation of the air conditioner is normal; If it is determined that the refrigerant circulation of the air conditioner is normal, then the compressor is controlled to operate at a reduced frequency or stop for defrosting based on the temperature in the middle of the internal pipe of the air conditioner. If it is determined that the refrigerant circulation of the air conditioner is abnormal, the compressor will be controlled to operate at a reduced frequency or stop for defrosting based on the temperature in the middle of the air conditioner's inner pipe and the compressor's suction saturation temperature.

2. The control method for an air conditioner according to claim 1, characterized in that, Based on the temperature at the middle of the air conditioner's inner pipe and the compressor's suction saturation temperature, determine whether the refrigerant circulation of the air conditioner is normal, including: Determine whether the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is less than or equal to a first set temperature difference threshold, and determine whether the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the suction saturation temperature of the compressor. If the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is less than or equal to the first set temperature difference threshold, then the refrigerant circulation of the air conditioner is determined to be normal. If it is determined that the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is greater than the first set temperature difference threshold, and it is determined that the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the suction saturation temperature of the compressor, then it is determined that the refrigerant circulation of the air conditioner is normal. If it is determined that the absolute value of the difference between the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor is greater than the first set temperature difference threshold, and it is determined that the temperature at the middle of the inner pipe of the air conditioner is greater than the suction saturation temperature of the compressor, then it is determined that the refrigerant circulation of the air conditioner is abnormal.

3. The control method for an air conditioner according to claim 1 or 2, characterized in that, Based on the temperature at the middle of the air conditioner's inner pipe, control the compressor to operate at a reduced frequency or stop for defrosting, including: Determine whether the temperature at the middle part of the inner pipe of the air conditioner is less than or equal to the first set temperature within a continuous second set time period; If it is determined that the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the first set temperature within a continuous second set time, the compressor is controlled to run at the frequency set in the cooling mode. If it is determined that the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the first set temperature within a second set time period, then the compressor is controlled to run at the frequency set in the cooling mode, and the frequency of the compressor is prohibited from increasing.

4. The control method for an air conditioner according to claim 3, characterized in that, Based on the temperature at the middle of the inner pipe of the air conditioner, controlling the compressor to operate at a reduced frequency or to stop for defrosting also includes: After controlling the compressor to operate at the frequency set in the cooling mode and prohibiting the compressor from increasing its frequency, it is determined whether the temperature of the middle part of the inner pipe of the air conditioner is less than or equal to the second set temperature within a third consecutive set time period; wherein the second set temperature is less than the first set temperature. If it is determined that the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the second set temperature within a third consecutive set time, then the compressor is controlled to run at the frequency set in the cooling mode and the frequency of the compressor is prohibited from increasing. Then, the process is returned to re-determine whether the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the first set temperature within a second consecutive set time. If it is determined that the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the second set temperature within a third consecutive set time period, the compressor is controlled to operate at a reduced frequency. The controlled compressor operation at a reduced frequency includes: controlling the compressor frequency to decrease by a first set frequency every fourth set time period, and controlling the compressor to operate at the reduced frequency.

5. The control method for an air conditioner according to claim 4, characterized in that, Based on the temperature at the middle of the inner pipe of the air conditioner, controlling the compressor to operate at a reduced frequency or to stop for defrosting also includes: After controlling the compressor to operate at a reduced frequency, it is determined whether the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the third set temperature within a continuous fifth set time period; wherein the third set temperature is less than the second set temperature. If it is determined that the temperature in the middle of the inner pipe of the air conditioner is less than or equal to the third set temperature within a continuous fifth set time, then the compressor is controlled to stop for defrosting. If it is determined that the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the third set temperature within a continuous fifth set time period, then the compressor is controlled to operate at a reduced frequency, and the process is repeated to re-determine whether the temperature at the middle of the inner pipe of the air conditioner is less than or equal to the second set temperature within a continuous third set time period.

6. The control method for an air conditioner according to claim 1 or 2, characterized in that, Based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor, the compressor is controlled to operate at reduced frequency or stop for defrosting, including: For the temperature of the inner pipe of the air conditioner and the suction saturation temperature of the compressor obtained at every sixth set time interval, the temperature of the inner pipe of the air conditioner obtained in two consecutive intervals is recorded as the i-th inner pipe temperature and the (i+1)-th inner pipe temperature; and the suction saturation temperature of the compressor obtained in two consecutive intervals is recorded as the i-th suction saturation temperature and the (i+1)-th suction saturation temperature; where i is the number of the first interval between two consecutive intervals and i is a positive integer, and i+1 is the number of the second interval between two consecutive intervals. Determine whether the following conditions are met: the temperature of the (i+1)th inner tube is less than the temperature of the ith inner tube, the (i+1)th intake saturation temperature is less than the ith intake saturation temperature, and the difference between the (i+1)th inner tube temperature and the ith inner tube temperature is greater than or equal to the second set temperature threshold. If the conditions are not met, the compressor is controlled to operate at the frequency set in the refrigeration mode program. If the conditions are met, the compressor is controlled to operate at the frequency set in the refrigeration mode, and the frequency of the compressor is prohibited from increasing.

7. The control method for an air conditioner according to claim 6, characterized in that, Based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor, controlling the compressor to operate at reduced frequency or to stop for defrosting also includes: After controlling the compressor to operate at the frequency set in the cooling mode and prohibiting the compressor from increasing its frequency, it is determined whether the following conditions are met: the temperature at the middle of the (i+1)th inner tube is lower than the temperature at the middle of the ith inner tube, the (i+1)th suction saturation temperature is lower than the ith suction saturation temperature, and the difference between the temperature at the middle of the (i+1)th inner tube and the temperature at the middle of the ith inner tube is greater than or equal to the second set temperature threshold; wherein the second set number of times is greater than the first set number of times. If not satisfied, the compressor is controlled to run at the frequency set in the cooling mode and the compressor frequency is prohibited from increasing. Then, the process returns to re-determine whether the following conditions are met: the temperature of the (i+1)th inner tube is less than the temperature of the ith inner tube, the (i+1)th suction saturation temperature is less than the ith suction saturation temperature, and the difference between the (i+1)th inner tube temperature and the temperature of the ith inner tube is greater than or equal to the second set temperature threshold. If the conditions are met, the compressor is controlled to operate at a reduced frequency; wherein, controlling the compressor to operate at a reduced frequency includes: controlling the compressor frequency to decrease by a second set frequency every seventh set time interval, and controlling the compressor to operate at the reduced frequency.

8. The control method for an air conditioner according to claim 7, characterized in that, Based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor, controlling the compressor to operate at reduced frequency or to stop for defrosting also includes: After controlling the compressor to operate at a reduced frequency, a first judgment logic and / or a second judgment logic are executed. The first judgment logic determines whether the following conditions are met: the (i+1)th consecutive set number of times the temperature at the middle of the inner tube is less than the temperature at the middle of the ith inner tube; the (i+1)th consecutive set number of times the suction saturation temperature is less than the ith suction saturation temperature; and the difference between the (i+1)th consecutive set number of times the temperature at the middle of the inner tube and the ith inner tube is greater than or equal to a second set temperature threshold. The second judgment logic determines whether the following conditions are met: the (i+1)th consecutive set number of times the temperature at the middle of the inner tube is less than the temperature at the ith inner tube; the (i+1)th consecutive set number of times the suction saturation temperature is less than the ith suction saturation temperature; and the difference between the (i+1)th consecutive set number of times the temperature at the middle of the inner tube and the ith inner tube is less than a second set temperature threshold. The third set number of times is greater than the second set number of times. If the judgment result of the first judgment logic is not satisfied, then under the condition of controlling the compressor to operate at a reduced frequency, return to re-determine whether the following conditions are met: the temperature of the middle part of the (i+1)th inner tube is less than the temperature of the middle part of the ith inner tube, the temperature of the (i+1)th suction saturation is less than the temperature of the ith suction saturation, and the difference between the temperature of the (i+1)th inner tube and the temperature of the middle part of the ith inner tube is greater than or equal to the second set temperature threshold. If the judgment result of the first judgment logic is satisfied, then control the compressor to stop for defrosting; If the result of the second judgment logic is not satisfied, then the first judgment logic is executed when the compressor is controlled to operate at a reduced frequency. If the judgment result of the second judgment logic is satisfied, then the compressor is controlled to stop for defrosting.

9. A control device for an air conditioner, characterized in that, The air conditioner has a compressor and an indoor heat exchanger; The control device for the air conditioner includes: The acquisition unit is configured to acquire the middle temperature of the indoor heat exchanger and record it as the middle temperature of the inner pipe of the air conditioner after the air conditioner is turned on and running in cooling mode for a first set time; and to acquire the pressure on the pipe where the suction port of the compressor is located and record it as the suction pressure of the compressor. The control unit is configured to determine, based on the suction pressure of the compressor, a saturation temperature corresponding to the suction pressure of the compressor, and denoted as the suction saturation temperature of the compressor. The control unit is also configured to determine whether the refrigerant circulation of the air conditioner is normal based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor. The control unit is also configured to, if it is determined that the refrigerant circulation of the air conditioner is normal, control the compressor to operate at a reduced frequency or stop defrosting based on the temperature in the middle of the inner pipe of the air conditioner. The control unit is also configured to, if it is determined that the refrigerant circulation of the air conditioner is abnormal, control the compressor to operate at a reduced frequency or stop for defrosting based on the temperature at the middle of the inner pipe of the air conditioner and the suction saturation temperature of the compressor.

10. An air conditioner, characterized in that, include: The control device for an air conditioner as described in claim 9.

11. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the control method of the air conditioner according to any one of claims 1 to 8.

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