Air conditioner and anti-freezing control method of air conditioner

Abstract

The application discloses an air conditioner and a freeze-proof control method of the air conditioner. In a refrigeration mode, a current exhaust temperature, a current outdoor coil temperature and a current indoor coil temperature are obtained; a current exhaust superheat is obtained according to the current exhaust temperature and the current outdoor coil temperature; whether the freeze-proof entering condition is met is judged according to the current indoor coil temperature and the current exhaust superheat; when the freeze-proof entering condition is met, the freeze-proof control of the air conditioner is realized by controlling the rotating speed of the compressor and the outdoor fan. The technical scheme of the application can improve the accuracy of the judgment result by judging whether the freeze-proof entering condition is met through the indoor coil temperature and the exhaust superheat of the air conditioner, and can greatly improve the timeliness of the freeze-proof control by simultaneously controlling the rotating speed of the outdoor fan and the compressor to realize the freeze-proof control of the air conditioner, so that the effectiveness of the freeze-proof control is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to an air conditioner and an anti-freezing control method for the air conditioner. Background Technology

[0002] Freezing in an air conditioner can cause several problems: First, it significantly reduces cooling efficiency because freezing reduces or prevents refrigerant flow, decreasing or eliminating refrigerant circulation within the system and thus reducing or eliminating cooling effectiveness. Second, freezing negatively impacts the compressor, which requires a continuous flow of refrigerant. When refrigerant circulation is obstructed, the compressor may overload or overheat, triggering a shutdown protection mechanism. This not only affects the air conditioner's normal operation but can also damage the compressor. Furthermore, frequent freezing and thawing cycles cause wear and tear on various components, shortening the overall lifespan of the air conditioner. If freezing is not addressed promptly, it may necessitate replacing parts or performing system repairs, increasing maintenance costs. Therefore, timely detection and resolution of air conditioner freezing issues are crucial to avoid these problems.

[0003] When an air conditioner is running in cooling mode, the high and low pressure sides of the refrigeration system affect each other. When the heat exchange on the high-pressure side (outdoor side) decreases, the pressure on the high-pressure side (outdoor side) will decrease, leading to an increase in the refrigerant on the low-pressure side (indoor side), which in turn causes the pressure on the low-pressure side (indoor side) to rise. At the same time, the outdoor fan of the air conditioner will reduce its speed, which will also affect the evaporation pressure on the indoor side. By making full use of these characteristics and setting the operating conditions of the air conditioner appropriately, the problem of air conditioner freezing can be solved, preventing the air conditioner from interrupting cooling due to entering anti-freeze protection (shutdown) during low-temperature cooling operation.

[0004] Currently, the industry generally controls the speed of the outdoor fan by measuring parameters such as the indoor coil temperature, exhaust pressure, and indoor evaporation pressure of the air conditioner to achieve anti-freezing control. However, this approach has low accuracy in determining whether the air conditioner is freezing, and simply adjusting the speed of the outdoor fan cannot quickly adjust the refrigeration system to prevent freezing, thus affecting the timeliness of anti-freezing control and compromising its effectiveness. Summary of the Invention

[0005] The purpose of this invention is to provide an air conditioner and an anti-freeze control method for the air conditioner. The method determines whether the anti-freeze entry conditions are met by using the indoor coil temperature and exhaust superheat of the air conditioner, which can improve the accuracy of the determination results. Furthermore, the anti-freeze control of the air conditioner is achieved by simultaneously controlling the speed of the outdoor fan and the compressor, which can greatly improve the timeliness of the anti-freeze control and ensure the effectiveness of the anti-freeze control.

[0006] To achieve the above objectives, embodiments of the present invention provide an air conditioner, comprising:

[0007] The refrigerant circuit circulates the refrigerant in a loop consisting of a compressor, a condenser, a throttling device, and an evaporator, wherein one of the condenser and the evaporator is an outdoor heat exchanger and the other is an indoor heat exchanger.

[0008] An outdoor fan is used to generate an airflow of outdoor air through the outdoor heat exchanger;

[0009] A first temperature sensor is used to detect the exhaust temperature of the compressor;

[0010] The second temperature sensor is used to detect the outdoor coil temperature;

[0011] The third temperature sensor is used to detect the indoor coil temperature;

[0012] Controller, used for:

[0013] In cooling mode, obtain the current exhaust temperature, current outdoor coil temperature, and current indoor coil temperature;

[0014] The current exhaust superheat is obtained based on the current exhaust temperature and the current outdoor coil temperature.

[0015] Determine whether the antifreeze entry conditions are met based on the current indoor coil temperature and the current exhaust superheat.

[0016] When the anti-freeze entry conditions are met, the air conditioner is subjected to anti-freeze control by controlling the speed of the compressor and the outdoor fan.

[0017] Furthermore, the controller determines whether the antifreeze entry conditions are met based on the current indoor coil temperature and the current exhaust superheat, specifically including:

[0018] Determine whether the current indoor coil temperature is below a preset first temperature threshold, and whether the current exhaust superheat is above a preset second temperature threshold;

[0019] When the current indoor coil temperature is below the first temperature threshold and the current exhaust superheat is above the second temperature threshold, the anti-freeze entry condition is determined to be met.

[0020] Furthermore, the controller determines whether the antifreeze entry conditions are met based on the current indoor coil temperature and the current exhaust superheat, specifically including:

[0021] Determine whether the current indoor coil temperature is below a preset first temperature threshold, and whether the current exhaust superheat is above a preset second temperature threshold;

[0022] If so, determine whether the duration of the current indoor coil temperature being below the first temperature threshold reaches a preset first time threshold, and whether the duration of the current exhaust superheat being above the second temperature threshold reaches a preset second time threshold.

[0023] If so, then the anti-freeze entry condition is met.

[0024] Furthermore, the controller performs anti-freeze control on the air conditioner by controlling the speed of the compressor and the outdoor fan, specifically including:

[0025] Reduce the speed of the compressor and the outdoor fan to implement anti-freeze control for the air conditioner.

[0026] Furthermore, the controller performs anti-freeze control on the air conditioner by controlling the speed of the compressor and the outdoor fan, specifically including:

[0027] Determine whether the compressor is at its lowest speed and whether the outdoor fan is at its lowest speed;

[0028] When the compressor is not at its lowest speed and the outdoor fan is not at its lowest speed, the speed of the compressor and the outdoor fan is reduced to perform anti-freeze control on the air conditioner.

[0029] Furthermore, the controller, by controlling the speed of the compressor and the outdoor fan to perform anti-freeze control on the air conditioner, also includes:

[0030] When the compressor is already at its lowest speed, and / or the outdoor fan is already at its lowest speed, control the compressor to continue running at its lowest speed, and / or control the outdoor fan to stop running, in order to perform anti-freeze control on the air conditioner.

[0031] Furthermore, the controller is also used for:

[0032] Determine whether the current indoor coil temperature is above a preset third temperature threshold, and whether the current exhaust superheat is below a preset fourth temperature threshold; wherein, the first temperature threshold is less than or equal to the third temperature threshold, and the second temperature threshold is greater than or equal to the fourth temperature threshold.

[0033] When the current indoor coil temperature is above the third temperature threshold and the current exhaust superheat is below the fourth temperature threshold, the anti-freeze exit condition is determined to be met.

[0034] Furthermore, the controller is also used for:

[0035] Determine whether the current indoor coil temperature is above a preset third temperature threshold, and whether the current exhaust superheat is below a preset fourth temperature threshold; wherein, the first temperature threshold is less than or equal to the third temperature threshold, and the second temperature threshold is greater than or equal to the fourth temperature threshold.

[0036] If so, determine whether the duration for which the current indoor coil temperature is above the third temperature threshold reaches the first time threshold, and whether the duration for which the current exhaust superheat is below the fourth temperature threshold reaches the second time threshold.

[0037] If so, then the anti-freeze exit condition is met.

[0038] Furthermore, the controller is also used for:

[0039] After determining that the anti-freeze exit conditions are met, the compressor speed is kept constant, and the outdoor fan speed is increased.

[0040] To achieve the above objectives, embodiments of the present invention also provide an anti-freezing control method for an air conditioner, applicable to any of the air conditioners described above, comprising:

[0041] In cooling mode, obtain the current exhaust temperature, current outdoor coil temperature, and current indoor coil temperature;

[0042] The current exhaust superheat is obtained based on the current exhaust temperature and the current outdoor coil temperature.

[0043] Determine whether the antifreeze entry conditions are met based on the current indoor coil temperature and the current exhaust superheat.

[0044] When the anti-freeze entry conditions are met, the air conditioner is subjected to anti-freeze control by controlling the speed of the compressor and the outdoor fan.

[0045] Compared with the prior art, the present invention provides an air conditioner and an anti-freeze control method for the air conditioner. The air conditioner includes: a refrigerant circuit, in which the refrigerant circulates in a circuit composed of a compressor, a condenser, a throttling device, and an evaporator, wherein one of the condenser and the evaporator is an outdoor heat exchanger and the other is an indoor heat exchanger; an outdoor fan, used to generate airflow of outdoor air through the outdoor heat exchanger; a first temperature sensor, used to detect the exhaust temperature of the compressor; a second temperature sensor, used to detect the outdoor coil temperature; a third temperature sensor, used to detect the indoor coil temperature; and a controller, used to: in cooling mode, acquire the current exhaust temperature, the current outdoor coil temperature, and the current indoor coil temperature; acquire the current exhaust superheat based on the current exhaust temperature and the current outdoor coil temperature; determine whether the anti-freeze entry condition is met based on the current indoor coil temperature and the current exhaust superheat; and when the anti-freeze entry condition is met, perform anti-freeze control on the air conditioner by controlling the speed of the compressor and the outdoor fan. This invention uses the indoor coil temperature and exhaust superheat of the air conditioner to determine whether the anti-freeze entry conditions are met, which improves the accuracy of the judgment results. Furthermore, by simultaneously controlling the speed of the outdoor fan and the compressor, the anti-freeze control of the air conditioner is achieved. This allows for rapid adjustment of the refrigeration system to prevent freezing problems, greatly improving the timeliness of anti-freeze control and ensuring its effectiveness. As a result, the air conditioner will not interrupt cooling during low-temperature cooling operation due to entering anti-freeze protection (shutdown), achieving continuous cooling and providing users with a better experience. Attached Figure Description

[0046] Figure 1 This is a three-dimensional structural diagram of an air conditioner provided in an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the internal structure of an air conditioner according to an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of the internal structure of an air conditioner according to another embodiment of the present invention;

[0049] Figure 4 This is a flowchart illustrating the operation of an air conditioner controller according to an embodiment of the present invention;

[0050] Figure 5 This is a flowchart of the operation of an air conditioner controller according to another embodiment of the present invention;

[0051] Figure 6 This is a flowchart of the operation of an air conditioner controller according to another embodiment of the present invention;

[0052] Figure 7This is a flowchart of the operation of an air conditioner controller according to another embodiment of the present invention;

[0053] Figure 8 This is a flowchart of the operation of an air conditioner controller according to another embodiment of the present invention;

[0054] Figure 9 This is a flowchart of the operation of an air conditioner controller according to another embodiment of the present invention;

[0055] Figure 10 This is a schematic flowchart of an anti-freezing control method for an air conditioner provided in an embodiment of the present invention. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] See Figure 1 and Figure 2 As shown, where, Figure 1 This is a three-dimensional structural diagram of an air conditioner according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the internal structure of an air conditioner according to an embodiment of the present invention; as shown. Figure 1 As shown, the air conditioner includes an indoor unit 100 and an outdoor unit 200. The indoor unit 100 is used to regulate the temperature and humidity of the indoor air. The outdoor unit 200 is connected to the indoor unit 100 through a connecting pipe. The indoor unit 100 is generally installed indoors, and the outdoor unit 200 is generally installed outdoors.

[0058] In an embodiment of the present invention, the air conditioner includes a refrigerant circuit, in which the refrigerant circulates in a circuit consisting of a compressor, a condenser, a throttling device, and an evaporator. One of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger. The air conditioner also includes an outdoor fan, which is used to generate an airflow of outdoor air through the outdoor heat exchanger.

[0059] like Figure 2As shown, the indoor unit 100 mainly includes an indoor heat exchanger (used as an evaporator in cooling mode), an indoor fan, and an indoor blower. The indoor heat exchanger achieves a cooling effect by utilizing the latent heat of refrigerant evaporation to exchange heat with the indoor air. The indoor fan is driven by the indoor blower and can generate airflow through the indoor heat exchanger to promote heat exchange between the refrigerant flowing in the heat transfer tube and the indoor air. The outdoor unit 200 mainly includes a compressor, an outdoor heat exchanger (used as a condenser in cooling mode), a throttling device, an outdoor fan, and an outdoor blower. The compressor compresses low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure refrigerant gas. The outdoor heat exchanger facilitates heat exchange between the refrigerant flowing inside and the outdoor air. The throttling device restricts the flow of refrigerant. The outdoor fan, driven by the outdoor blower, generates airflow through the outdoor heat exchanger, promoting heat exchange between the refrigerant flowing in the heat transfer tubes and the outdoor air. Furthermore, the outdoor unit 200 may also include a four-way valve, primarily used to control the flow direction of the refrigerant in the refrigerant circuit, allowing the outdoor and indoor heat exchangers to switch between functioning as a condenser and an evaporator.

[0060] See Figure 3 The diagram shown is a schematic representation of the internal structure of an air conditioner according to another embodiment of the present invention. In this embodiment, the air conditioner further includes a first temperature sensor, a second temperature sensor, and a third temperature sensor. The first temperature sensor is used to detect the discharge temperature of the compressor in real time; the second temperature sensor is used to detect the outdoor coil temperature of the outdoor heat exchanger in real time (when the outdoor heat exchanger is used as a condenser in cooling mode, i.e., to detect the condenser coil temperature in real time); and the third temperature sensor is used to detect the indoor coil temperature of the indoor heat exchanger in real time (when the indoor heat exchanger is used as an evaporator in cooling mode, i.e., to detect the evaporator coil temperature in real time). Figure 3 As shown, the first temperature sensor can generally be installed on the compressor's exhaust pipe and about 35mm from the compressor's exhaust port. The second temperature sensor can generally be installed in the middle of the outdoor heat exchanger. The third temperature sensor can generally be installed near the outlet of the indoor heat exchanger.

[0061] In this embodiment of the invention, the air conditioner further includes a controller, which is used to control the operation of various components in the air conditioner (e.g., compressor, outdoor fan, etc.) to enable the various components of the air conditioner to operate and realize various functions of the air conditioner. Furthermore, the controller is also used to connect to a first temperature sensor, a second temperature sensor, and a third temperature sensor to receive temperature data detected in real time by the first temperature sensor, the second temperature sensor, and the third temperature sensor, and to use the technical solution provided in this embodiment of the invention to control the air conditioner accordingly, so as to solve the technical problems to be solved by this embodiment of the invention and realize the technical effects that this embodiment of the invention can achieve.

[0062] As one optional embodiment, the controller is used for:

[0063] In cooling mode, obtain the current exhaust temperature, current outdoor coil temperature, and current indoor coil temperature;

[0064] The current exhaust superheat is obtained based on the current exhaust temperature and the current outdoor coil temperature.

[0065] Determine whether the antifreeze entry conditions are met based on the current indoor coil temperature and the current exhaust superheat.

[0066] When the anti-freeze entry conditions are met, the air conditioner is subjected to anti-freeze control by controlling the speed of the compressor and the outdoor fan.

[0067] Combination Figure 4 The diagram shown is a flowchart of the operation of an air conditioner controller according to an embodiment of the present invention. In a specific implementation of this embodiment, the controller's operation is as follows: The air conditioner receives a cooling command and operates in cooling mode (…). Figure 4 Step S11 (shown); When the air conditioner is running in cooling mode, the current discharge temperature of the compressor, the current outdoor coil temperature of the outdoor heat exchanger (i.e., the current coil temperature of the condenser), and the current indoor coil temperature of the indoor heat exchanger (i.e., the current coil temperature of the evaporator) are obtained in real time using the first temperature sensor, the second temperature sensor, and the third temperature sensor, respectively. Figure 4 Step S12 (as shown); calculate the current exhaust superheat based on the real-time acquired current exhaust temperature and current outdoor coil temperature. Figure 4 Step S13 (as shown); Based on the real-time acquired current indoor coil temperature and the calculated current exhaust superheat, determine whether the air conditioner meets the anti-freeze entry conditions. Figure 4 Step S14 (as shown); When it is determined that the air conditioner meets the anti-freeze entry conditions, the air conditioner is controlled to enter the anti-freeze control program: the speed of the compressor and the speed of the outdoor fan are controlled respectively to perform anti-freeze control on the air conditioner. Figure 4(Step S15 shown).

[0068] It should be noted that when the controller calculates the current exhaust superheat based on the real-time acquired current exhaust temperature and current outdoor coil temperature (i.e., the current coil temperature of the condenser), it can directly perform the automatic calculation using the formula: Current Exhaust Superheat = Current Exhaust Temperature - Current Coil Temperature of the Condenser. The exhaust superheat (DSH) should typically be the exhaust temperature minus the saturation temperature corresponding to the condensing pressure. The sensing point for the condenser coil temperature is generally selected within the saturation pressure range of the condenser; therefore, the condenser coil temperature can be used to represent the saturation temperature corresponding to the condensing pressure.

[0069] Understandably, after the controller determines whether the air conditioner meets the anti-freeze entry conditions based on the real-time indoor coil temperature and the calculated current exhaust superheat, if it determines that the air conditioner does not meet the anti-freeze entry conditions, then there is no need to control the air conditioner to enter the anti-freeze control program. The compressor speed and the outdoor fan speed can remain unchanged, and the system can continue to operate from... Figure 4 Step S14 shown returns Figure 4 In step S12, wait for the next time to reacquire the current discharge temperature of the compressor, the current outdoor coil temperature of the outdoor heat exchanger, and the current indoor coil temperature of the indoor heat exchanger, and perform the corresponding processing.

[0070] It should be noted that, in this embodiment of the invention, the indoor coil temperature and exhaust superheat are used as the criteria for determining whether the air conditioner enters anti-freeze control. These two parameters can fully reflect the system parameter characteristics of the air conditioner's low-temperature cooling operation. Among them, the indoor coil temperature itself has a direct and effective characteristic. However, in actual applications, the evaporator often has multiple branches, and under different operating conditions, the branches may deviate. The degree of deviance will be reflected in the change of exhaust superheat (DSH). Therefore, in addition to the indoor coil temperature, it is also necessary to consider the exhaust superheat (DSH). Thus, this embodiment of the invention determines whether the anti-freeze entry condition is met based on the indoor coil temperature and exhaust superheat, and the judgment result obtained is very accurate. Furthermore, using the indoor coil temperature and exhaust superheat as control conditions to control the compressor speed and the outdoor fan speed can ensure the effectiveness of anti-freeze control.

[0071] An air conditioner provided in this invention includes: a refrigerant circuit for circulating refrigerant in a circuit consisting of a compressor, a condenser, a throttling device, and an evaporator, wherein one of the condenser and the evaporator is an outdoor heat exchanger and the other is an indoor heat exchanger; an outdoor fan for generating airflow of outdoor air through the outdoor heat exchanger; a first temperature sensor for detecting the compressor's exhaust temperature; a second temperature sensor for detecting the outdoor coil temperature; a third temperature sensor for detecting the indoor coil temperature; and a controller for: in cooling mode, acquiring the current exhaust temperature, the current outdoor coil temperature, and the current indoor coil temperature; acquiring the current exhaust superheat based on the current exhaust temperature and the current outdoor coil temperature; determining whether the anti-freeze entry condition is met based on the current indoor coil temperature and the current exhaust superheat; and when the anti-freeze entry condition is met, controlling the speed of the compressor and the outdoor fan to perform anti-freeze control on the air conditioner. This invention uses the indoor coil temperature and exhaust superheat of the air conditioner to determine whether the anti-freeze entry conditions are met, which improves the accuracy of the judgment results. Furthermore, by simultaneously controlling the speed of the outdoor fan and the compressor, the anti-freeze control of the air conditioner is achieved. This allows for rapid adjustment of the refrigeration system to prevent freezing problems, greatly improving the timeliness of anti-freeze control and ensuring its effectiveness. As a result, the air conditioner will not interrupt cooling due to entering anti-freeze protection (shutdown) during low-temperature cooling operation (it can still cool normally in low-temperature winter conditions in cold regions), achieving continuous cooling and providing users with a better experience.

[0072] As one optional embodiment, the controller determines whether the anti-freeze entry condition is met based on the current indoor coil temperature and the current exhaust superheat, specifically including:

[0073] Determine whether the current indoor coil temperature is below a preset first temperature threshold, and whether the current exhaust superheat is above a preset second temperature threshold;

[0074] When the current indoor coil temperature is below the first temperature threshold and the current exhaust superheat is above the second temperature threshold, the anti-freeze entry condition is determined to be met.

[0075] Combination Figure 5 The diagram shown is a flowchart of the controller for an air conditioner according to another embodiment of the present invention. Based on the above embodiment, in specific implementation of this embodiment, when the controller determines whether the air conditioner meets the anti-freeze entry conditions based on the real-time acquired current indoor coil temperature and the calculated current exhaust superheat, it can determine whether the real-time acquired current indoor coil temperature is below a preset first temperature threshold, and whether the calculated current exhaust superheat is above a preset second temperature threshold. Figure 5 Step S1411 (shown): When it is determined that the real-time acquired current indoor coil temperature is below the preset first temperature threshold, and the calculated current exhaust superheat is above the preset second temperature threshold, it is determined that the air conditioner meets the anti-freeze entry condition, and the air conditioner can be controlled to enter the anti-freeze control program (i.e., execute). Figure 5 (Step S15 shown).

[0076] For example, assuming the first temperature threshold is -2℃ and the second temperature threshold is 30℃, then it is determined whether the current indoor coil temperature and the current exhaust superheat meet the following conditions: the current indoor coil temperature < -2℃ and the current exhaust superheat > 30℃. If the current indoor coil temperature < -2℃ and the current exhaust superheat > 30℃ are met, then the air conditioner is determined to meet the anti-freeze entry conditions; otherwise, the air conditioner is determined not to meet the anti-freeze entry conditions.

[0077] As one optional embodiment, the controller determines whether the anti-freeze entry condition is met based on the current indoor coil temperature and the current exhaust superheat, specifically including:

[0078] Determine whether the current indoor coil temperature is below a preset first temperature threshold, and whether the current exhaust superheat is above a preset second temperature threshold;

[0079] If so, determine whether the duration of the current indoor coil temperature being below the first temperature threshold reaches a preset first time threshold, and whether the duration of the current exhaust superheat being above the second temperature threshold reaches a preset second time threshold.

[0080] If so, then the anti-freeze entry condition is met.

[0081] Combination Figure 6 The diagram shown is a flowchart of the controller for an air conditioner according to another embodiment of the present invention. Based on the above embodiment, in specific implementation of this embodiment, when the controller determines whether the air conditioner meets the anti-freeze entry conditions based on the real-time acquired current indoor coil temperature and the calculated current exhaust superheat, it can first determine whether the real-time acquired current indoor coil temperature is below a preset first temperature threshold, and whether the calculated current exhaust superheat is above a preset second temperature threshold. Figure 6(See step S1421); When it is determined that the real-time acquired current indoor coil temperature is below a preset first temperature threshold, and the calculated current exhaust superheat is above a preset second temperature threshold, it is further determined whether the duration of the real-time acquired current indoor coil temperature being below the preset first temperature threshold has reached a preset first time threshold, and whether the duration of the calculated current exhaust superheat being above the preset second temperature threshold has reached a preset second time threshold. Figure 6 Step S1422 (shown): When the duration for which the real-time acquired current indoor coil temperature is below a preset first temperature threshold reaches a preset first time threshold, and the duration for which the calculated current exhaust superheat is above a preset second temperature threshold reaches a preset second time threshold, it is determined that the air conditioner meets the anti-freeze entry condition, and the air conditioner can be controlled to enter the anti-freeze control program (i.e., execute...). Figure 6 (Step S15 shown).

[0082] It should be noted that the first time threshold and the second time threshold can be 1 minute, 2 minutes or other values, and the first time threshold and the second time threshold can be the same or different. The specific values ​​of the two can be preset according to the actual situation, and the embodiments of the present invention do not make specific limitations.

[0083] For example, assuming the first temperature threshold is -2℃, the second temperature threshold is 30℃, the first time threshold is 2min, and the second time threshold is 2min, then first determine whether the current indoor coil temperature and the current exhaust superheat meet the following conditions: the current indoor coil temperature < -2℃ and the current exhaust superheat > 30℃. If the conditions are met, then the air conditioner is determined to meet the following conditions: the current indoor coil temperature < -2℃ lasts for 2min and the current exhaust superheat > 30℃ lasts for 2min. If these conditions are met, the air conditioner is determined to meet the anti-freeze entry conditions; otherwise, the air conditioner is determined not to meet the anti-freeze entry conditions.

[0084] This invention, by setting a duration for which the current indoor coil temperature and the current exhaust superheat meet certain conditions, can avoid distortion and misjudgment caused by fluctuations in the refrigeration system due to other factors, thus further improving the accuracy of the judgment results. For example, if the current indoor coil temperature and the current exhaust superheat meet certain conditions for a certain period of time, the activation of the anti-freeze control program will be more accurate.

[0085] As one optional embodiment, the controller performs anti-freezing control on the air conditioner by controlling the speed of the compressor and the outdoor fan, specifically including:

[0086] Reduce the speed of the compressor and the outdoor fan to implement anti-freeze control for the air conditioner.

[0087] Combination Figure 7 The diagram shown is a flowchart of the controller for an air conditioner according to another embodiment of the present invention. Based on the above embodiment, in specific implementation of this embodiment, after the controller determines that the air conditioner meets the anti-freeze entry conditions and controls the air conditioner to enter the anti-freeze control program, when performing anti-freeze control on the air conditioner by controlling the compressor speed and the outdoor fan speed, it can reduce the compressor speed and control the compressor to continue running at the reduced speed, and reduce the outdoor fan speed and control the outdoor fan to continue running at the reduced speed, thereby performing anti-freeze control on the air conditioner. Figure 7 (Step S1511 shown).

[0088] It should be noted that when the controller reduces the compressor speed, it can reduce the compressor speed according to the preset speed reduction range. Since the outdoor fan speed is generally adjusted by changing the speed setting, the controller can reduce the outdoor fan speed by lowering the outdoor fan speed by one setting. For example, outdoor fans generally have high, medium, and low speed settings. Assuming that the outdoor fan is currently at the medium speed setting, the controller can reduce the outdoor fan speed from the medium speed setting to the low speed setting.

[0089] As one optional embodiment, the controller performs anti-freezing control on the air conditioner by controlling the speed of the compressor and the outdoor fan, specifically including:

[0090] Determine whether the compressor is at its lowest speed and whether the outdoor fan is at its lowest speed;

[0091] When the compressor is not at its lowest speed and the outdoor fan is not at its lowest speed, the speed of the compressor and the outdoor fan is reduced to perform anti-freeze control on the air conditioner.

[0092] Combination Figure 8 The diagram shown is a flowchart of the controller for an air conditioner according to another embodiment of the present invention. Based on the above embodiments, in specific implementation of this embodiment, after the controller determines that the air conditioner meets the anti-freeze entry conditions and controls the air conditioner to enter the anti-freeze control program, when performing anti-freeze control on the air conditioner by controlling the compressor speed and the outdoor fan speed, it can first determine whether the compressor is currently at its lowest speed. Figure 8 Step S1521 is shown, and it is determined whether the outdoor fan is currently at its lowest speed. Figure 8 (See step S1522); When it is determined that the compressor is not currently at its lowest speed and the outdoor fan is not currently at its lowest speed, the compressor speed is further reduced, and the compressor is controlled to continue running at the reduced speed. The outdoor fan speed is also reduced, and the outdoor fan is controlled to continue running at the reduced speed, in order to perform anti-freeze control on the air conditioner. Figure 8 (Step S1523 shown).

[0093] Understandably, after the controller puts the air conditioner into the anti-freeze control program, it needs to reduce the speed of the compressor and the outdoor fan. However, the speed of the compressor and the outdoor fan cannot be reduced indefinitely. Therefore, before reducing the speed of the compressor and the outdoor fan, the controller can first determine whether the current speed of the compressor and the current speed of the outdoor fan are already at their respective minimum achievable speeds. Only when it is determined that the current speed of the compressor and the current speed of the outdoor fan are not at their respective minimum achievable speeds will it be allowed to continue to reduce the speed of the compressor and the outdoor fan.

[0094] As one optional embodiment, the controller performs anti-freeze control on the air conditioner by controlling the speed of the compressor and the outdoor fan, and further includes:

[0095] When the compressor is already at its lowest speed, and / or the outdoor fan is already at its lowest speed, control the compressor to continue running at its lowest speed, and / or control the outdoor fan to stop running, in order to perform anti-freeze control on the air conditioner.

[0096] Combination Figure 9 The diagram shown is a flowchart of the controller for an air conditioner according to another embodiment of the present invention. Based on the above embodiment, in specific implementation of this embodiment, after determining whether the compressor is currently at its lowest speed and whether the outdoor fan is currently at its lowest speed, if it is determined that the compressor is currently at its lowest speed, and / or the outdoor fan is currently at its lowest speed, then the compressor can be controlled to continue operating at its lowest speed. Figure 9 Step S1524 shown), or / and, control the outdoor fan to stop operating. Figure 9 Step S1525 (shown) is used to perform anti-freeze control on the air conditioner.

[0097] It should be noted that when the inverter compressor is at its lowest speed, freezing will generally not occur. Therefore, it is sufficient to keep the compressor running at its lowest speed.

[0098] Understandably, if it is determined that the compressor's current speed is already at its minimum speed, but the outdoor fan's current speed is not, then the compressor can be controlled to continue running at its minimum speed, and the outdoor fan's speed can be reduced to continue running at the reduced speed. If it is determined that the compressor's current speed is not at its minimum speed, but the outdoor fan's current speed is already at its minimum speed, then the compressor's speed can be reduced to continue running at the reduced speed, and the outdoor fan can be stopped. If it is determined that both the compressor's current speed and the outdoor fan's current speed are already at their minimum speed, then the compressor can be controlled to continue running at its minimum speed, and the outdoor fan can be stopped.

[0099] As one optional embodiment, the controller is further configured to:

[0100] Determine whether the current indoor coil temperature is above a preset third temperature threshold, and whether the current exhaust superheat is below a preset fourth temperature threshold; wherein, the first temperature threshold is less than or equal to the third temperature threshold, and the second temperature threshold is greater than or equal to the fourth temperature threshold.

[0101] When the current indoor coil temperature is above the third temperature threshold and the current exhaust superheat is below the fourth temperature threshold, the anti-freeze exit condition is determined to be met.

[0102] It should be noted that if the air conditioner has entered the anti-freeze control program, during the anti-freeze control process, the controller can use the first temperature sensor, the second temperature sensor, and the third temperature sensor to obtain the current discharge temperature of the compressor and the current outdoor coil temperature of the outdoor heat exchanger in real time, respectively. Based on the real-time obtained current discharge temperature and current outdoor coil temperature, the controller calculates the current discharge superheat. Based on the real-time obtained current indoor coil temperature and the calculated current discharge superheat, the controller determines whether the air conditioner meets the anti-freeze exit conditions. If the air conditioner does not meet the anti-freeze exit conditions, the anti-freeze control of the air conditioner continues. If the air conditioner meets the anti-freeze exit conditions, the controller can control the air conditioner to exit the anti-freeze control program.

[0103] Based on the above embodiments, in specific implementation of this embodiment, the controller is further configured to determine whether the air conditioner meets the anti-freeze exit condition in one of the following ways: determining whether the real-time acquired current indoor coil temperature is above a preset third temperature threshold, and whether the calculated current exhaust superheat is below a preset fourth temperature threshold; when it is determined that the real-time acquired current indoor coil temperature is above a preset third temperature threshold, and the calculated current exhaust superheat is below a preset fourth temperature threshold, the air conditioner is determined to meet the anti-freeze exit condition, and the air conditioner can be controlled to exit the anti-freeze control program.

[0104] It should be noted that the first temperature threshold is less than or equal to the third temperature threshold, and the second temperature threshold is greater than or equal to the fourth temperature threshold. That is, the first and third temperature thresholds can be set to the same temperature threshold or different temperature thresholds. Similarly, the second and fourth temperature thresholds can be set to the same temperature threshold or different temperature thresholds. However, if the first and third temperature thresholds are set to the same time threshold, and the second and fourth temperature thresholds are set to the same time threshold, frequent entry and exit of the anti-freeze control program may occur, leading to increased fatigue of the air conditioner's electrical components and insufficient duration for anti-freeze control, thus affecting the anti-freeze control effect. Therefore, the first and third temperature thresholds are generally set to different temperature thresholds, and the second and fourth temperature thresholds are also set to different temperature thresholds.

[0105] For example, assuming the third temperature threshold is 5℃ and the fourth temperature threshold is 29℃, then it is determined whether the current indoor coil temperature and the current exhaust superheat meet the following conditions: the current indoor coil temperature ≥ 5℃ and the current exhaust superheat ≤ 29℃. If the current indoor coil temperature ≥ 5℃ and the current exhaust superheat ≤ 29℃ are met, then the air conditioner is determined to meet the anti-freeze exit condition; otherwise, the air conditioner is determined not to meet the anti-freeze exit condition.

[0106] As one optional embodiment, the controller is further configured to:

[0107] Determine whether the current indoor coil temperature is above a preset third temperature threshold, and whether the current exhaust superheat is below a preset fourth temperature threshold; wherein, the first temperature threshold is less than or equal to the third temperature threshold, and the second temperature threshold is greater than or equal to the fourth temperature threshold.

[0108] If so, determine whether the duration for which the current indoor coil temperature is above the third temperature threshold reaches the first time threshold, and whether the duration for which the current exhaust superheat is below the fourth temperature threshold reaches the second time threshold.

[0109] If so, then the anti-freeze exit condition is met.

[0110] Based on the above embodiments, in specific implementation of this embodiment, the controller is further configured to determine whether the air conditioner meets the anti-freeze exit condition in another way: first, determine whether the real-time acquired current indoor coil temperature is above a preset third temperature threshold, and whether the calculated current exhaust superheat is below a preset fourth temperature threshold; when it is determined that the real-time acquired current indoor coil temperature is above the preset third temperature threshold, and the calculated current exhaust superheat is below the preset fourth temperature threshold, further determine whether the duration for which the real-time acquired current indoor coil temperature is above the preset third temperature threshold reaches a preset first time threshold, and whether the duration for which the calculated current exhaust superheat is below the preset fourth temperature threshold reaches a preset second time threshold; when it is determined that the duration for which the real-time acquired current indoor coil temperature is above the preset third temperature threshold reaches the preset first time threshold, and the duration for which the calculated current exhaust superheat is below the preset fourth temperature threshold reaches the preset second time threshold, the air conditioner is determined to meet the anti-freeze exit condition, and the air conditioner can be controlled to exit the anti-freeze control program.

[0111] For example, assuming the third temperature threshold is 5℃, the fourth temperature threshold is 29℃, the first time threshold is 2min, and the second time threshold is 2min, then first determine whether the current indoor coil temperature and the current exhaust superheat meet the following conditions: the current indoor coil temperature ≥ 5℃ and the current exhaust superheat ≤ 29℃. If the conditions are met, then the air conditioner is determined to meet the following conditions: the current indoor coil temperature ≥ 5℃ lasts for 2min and the current exhaust superheat ≤ 29℃ lasts for 2min. If these conditions are met, the air conditioner is determined to meet the anti-freeze exit conditions; otherwise, the air conditioner is determined not to meet the anti-freeze exit conditions.

[0112] This invention improves the accuracy of judgments by setting a duration for which the current indoor coil temperature and the current exhaust superheat meet certain conditions. This avoids distortion and misjudgment caused by fluctuations in the refrigeration system due to other factors. For example, if the current indoor coil temperature and the current exhaust superheat meet certain conditions for a sustained period, the exit of the anti-freeze control program will be more accurate.

[0113] As one optional embodiment, the controller is further configured to:

[0114] After determining that the anti-freeze exit conditions are met, the compressor speed is kept constant, and the outdoor fan speed is increased.

[0115] Based on the above embodiments, in specific implementation of the present invention, after the controller determines that the air conditioner meets the anti-freeze exit conditions and controls the air conditioner to exit the anti-freeze control program, it can control the compressor speed to remain unchanged, that is, control the compressor to continue running at the current speed and increase the speed of the outdoor fan, and control the outdoor fan to continue running at the increased speed.

[0116] It should be noted that since outdoor fans generally adjust their speed by changing the gear, the controller can increase the speed of the outdoor fan by increasing the gear by one level. For example, outdoor fans generally have high, medium, and low speeds. Assuming the outdoor fan is currently at the medium speed, the controller can increase the speed of the outdoor fan from the medium speed to the high speed.

[0117] Understandably, after the controller exits the anti-freeze control program, it needs to increase the outdoor fan speed. However, the outdoor fan speed cannot be increased indefinitely. Therefore, before increasing the outdoor fan speed, the controller can first determine whether the current speed of the outdoor fan is already at its maximum achievable speed (e.g., the speed corresponding to the high fan speed setting). Only if it is determined that the current speed of the outdoor fan is not at its maximum achievable speed will it be allowed to continue increasing the outdoor fan speed. If it is determined that the current speed of the outdoor fan is already at its maximum achievable speed, the controller can control the outdoor fan to continue running at the highest speed.

[0118] It should be noted that, in conjunction with all the above embodiments, the following applies to the magnitude and duration of the relationship between the current indoor coil temperature and the first and third temperature thresholds, as well as the magnitude and duration of the current exhaust superheat between the second and fourth temperature thresholds:

[0119] If it is determined that the duration of the current indoor coil temperature being below the first temperature threshold reaches the first time threshold, and the duration of the current exhaust superheat being above the second temperature threshold reaches the second time threshold, then it is determined that the air conditioner meets the anti-freeze entry conditions, and the air conditioner can be controlled to enter the anti-freeze control program to control the compressor speed and the outdoor fan speed accordingly (see the above embodiment for details).

[0120] If the duration of the current indoor coil temperature being above the third temperature threshold reaches the first time threshold, and the duration of the current exhaust superheat being below the fourth temperature threshold reaches the second time threshold, then the air conditioner is determined to meet the anti-freeze exit condition, and the air conditioner can be controlled to exit the anti-freeze control program, and the compressor speed and outdoor fan speed can be controlled accordingly (see the above embodiment for details).

[0121] In addition to the two judgment results of meeting the anti-freeze entry condition and meeting the anti-freeze exit condition, there are other judgment results, such as the current indoor coil temperature being between the first and third temperature thresholds, the current exhaust superheat being between the second and fourth temperature thresholds, the current indoor coil temperature meeting certain conditions for a duration that does not reach the first time threshold, the current exhaust superheat meeting certain conditions for a duration that does not reach the second time threshold, etc. Under these other judgment results, there is no need to adjust the compressor speed and the outdoor fan speed; they can be kept unchanged.

[0122] This invention also provides an anti-freezing control method for air conditioners, see [link to relevant documentation]. Figure 10 The diagram shown is a flowchart illustrating an anti-freezing control method for an air conditioner according to an embodiment of the present invention. The method is applicable to the air conditioner described in any of the above embodiments. The method is executed by the controller and includes steps S101 to S104:

[0123] Step S101: In cooling mode, obtain the current exhaust temperature, the current outdoor coil temperature, and the current indoor coil temperature;

[0124] Step S102: Obtain the current exhaust superheat based on the current exhaust temperature and the current outdoor coil temperature;

[0125] Step S103: Determine whether the antifreeze entry conditions are met based on the current indoor coil temperature and the current exhaust superheat.

[0126] Step S104: When the anti-freeze entry conditions are met, the air conditioner is subjected to anti-freeze control by controlling the speed of the compressor and the outdoor fan.

[0127] In some embodiments, determining whether the antifreeze entry condition is met based on the current indoor coil temperature and the current exhaust superheat specifically includes:

[0128] Determine whether the current indoor coil temperature is below a preset first temperature threshold, and whether the current exhaust superheat is above a preset second temperature threshold;

[0129] When the current indoor coil temperature is below the first temperature threshold and the current exhaust superheat is above the second temperature threshold, the anti-freeze entry condition is determined to be met.

[0130] In some embodiments, determining whether the antifreeze entry condition is met based on the current indoor coil temperature and the current exhaust superheat specifically includes:

[0131] Determine whether the current indoor coil temperature is below a preset first temperature threshold, and whether the current exhaust superheat is above a preset second temperature threshold;

[0132] If so, determine whether the duration of the current indoor coil temperature being below the first temperature threshold reaches a preset first time threshold, and whether the duration of the current exhaust superheat being above the second temperature threshold reaches a preset second time threshold.

[0133] If so, then the anti-freeze entry condition is met.

[0134] In some embodiments, the anti-freezing control of the air conditioner by controlling the speed of the compressor and the outdoor fan specifically includes:

[0135] Reduce the speed of the compressor and the outdoor fan to implement anti-freeze control for the air conditioner.

[0136] In some embodiments, the anti-freezing control of the air conditioner by controlling the speed of the compressor and the outdoor fan specifically includes:

[0137] Determine whether the compressor is at its lowest speed and whether the outdoor fan is at its lowest speed;

[0138] When the compressor is not at its lowest speed and the outdoor fan is not at its lowest speed, the speed of the compressor and the outdoor fan is reduced to perform anti-freeze control on the air conditioner.

[0139] In some embodiments, the step of controlling the air conditioner to prevent freezing by controlling the speed of the compressor and the outdoor fan further includes:

[0140] When the compressor is already at its lowest speed, and / or the outdoor fan is already at its lowest speed, control the compressor to continue running at its lowest speed, and / or control the outdoor fan to stop running, in order to perform anti-freeze control on the air conditioner.

[0141] In some embodiments, the method further includes:

[0142] Determine whether the current indoor coil temperature is above a preset third temperature threshold, and whether the current exhaust superheat is below a preset fourth temperature threshold; wherein, the first temperature threshold is less than or equal to the third temperature threshold, and the second temperature threshold is greater than or equal to the fourth temperature threshold.

[0143] When the current indoor coil temperature is above the third temperature threshold and the current exhaust superheat is below the fourth temperature threshold, the anti-freeze exit condition is determined to be met.

[0144] In some embodiments, the method further includes:

[0145] Determine whether the current indoor coil temperature is above a preset third temperature threshold, and whether the current exhaust superheat is below a preset fourth temperature threshold; wherein, the first temperature threshold is less than or equal to the third temperature threshold, and the second temperature threshold is greater than or equal to the fourth temperature threshold.

[0146] If so, determine whether the duration for which the current indoor coil temperature is above the third temperature threshold reaches the first time threshold, and whether the duration for which the current exhaust superheat is below the fourth temperature threshold reaches the second time threshold.

[0147] If so, then the anti-freeze exit condition is met.

[0148] In some embodiments, the method further includes:

[0149] After determining that the anti-freeze exit conditions are met, the compressor speed is kept constant, and the outdoor fan speed is increased.

[0150] It should be noted that the anti-freezing control method for an air conditioner provided in this embodiment of the invention can realize all the working processes of the air conditioner described in any of the above embodiments. The specific implementation schemes and technical effects of the method are the same as those of the specific implementation schemes and technical effects of the air conditioner described in the above embodiments, and will not be repeated here.

[0151] The above description is only some embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An air conditioner, characterized in that, include: The refrigerant circuit circulates the refrigerant in a loop consisting of a compressor, a condenser, a throttling device, and an evaporator, wherein one of the condenser and the evaporator is an outdoor heat exchanger and the other is an indoor heat exchanger. An outdoor fan is used to generate an airflow of outdoor air through the outdoor heat exchanger; A first temperature sensor is used to detect the exhaust temperature of the compressor; The second temperature sensor is used to detect the outdoor coil temperature; The third temperature sensor is used to detect the indoor coil temperature; Controller, used for: In cooling mode, obtain the current exhaust temperature, current outdoor coil temperature, and current indoor coil temperature; The current exhaust superheat is obtained based on the current exhaust temperature and the current outdoor coil temperature. Determine whether the antifreeze entry conditions are met based on the current indoor coil temperature and the current exhaust superheat. When the anti-freeze entry conditions are met, the air conditioner is subjected to anti-freeze control by controlling the speed of the compressor and the outdoor fan.

2. The air conditioner as described in claim 1, characterized in that, The controller determines whether the antifreeze entry conditions are met based on the current indoor coil temperature and the current exhaust superheat, specifically including: Determine whether the current indoor coil temperature is below a preset first temperature threshold, and whether the current exhaust superheat is above a preset second temperature threshold; When the current indoor coil temperature is below the first temperature threshold and the current exhaust superheat is above the second temperature threshold, the anti-freeze entry condition is determined to be met.

3. The air conditioner as described in claim 1, characterized in that, The controller determines whether the antifreeze entry conditions are met based on the current indoor coil temperature and the current exhaust superheat, specifically including: Determine whether the current indoor coil temperature is below a preset first temperature threshold, and whether the current exhaust superheat is above a preset second temperature threshold; If so, determine whether the duration of the current indoor coil temperature being below the first temperature threshold reaches a preset first time threshold, and whether the duration of the current exhaust superheat being above the second temperature threshold reaches a preset second time threshold. If so, then the anti-freeze entry condition is met.

4. The air conditioner as described in claim 1, characterized in that, The controller performs anti-freezing control on the air conditioner by controlling the speed of the compressor and the outdoor fan, specifically including: Reduce the speed of the compressor and the outdoor fan to implement anti-freeze control for the air conditioner.

5. The air conditioner as described in claim 1, characterized in that, The controller performs anti-freezing control on the air conditioner by controlling the speed of the compressor and the outdoor fan, specifically including: Determine whether the compressor is at its lowest speed and whether the outdoor fan is at its lowest speed; When the compressor is not at its lowest speed and the outdoor fan is not at its lowest speed, the speed of the compressor and the outdoor fan is reduced to perform anti-freeze control on the air conditioner.

6. The air conditioner as described in claim 5, characterized in that, The controller performs anti-freezing control on the air conditioner by controlling the speed of the compressor and the outdoor fan, and also includes: When the compressor is already at its lowest speed, and / or the outdoor fan is already at its lowest speed, control the compressor to continue running at its lowest speed, and / or control the outdoor fan to stop running, in order to perform anti-freeze control on the air conditioner.

7. The air conditioner as described in claim 2, characterized in that, The controller is also used for: Determine whether the current indoor coil temperature is above a preset third temperature threshold, and whether the current exhaust superheat is below a preset fourth temperature threshold; wherein, the first temperature threshold is less than or equal to the third temperature threshold, and the second temperature threshold is greater than or equal to the fourth temperature threshold. When the current indoor coil temperature is above the third temperature threshold and the current exhaust superheat is below the fourth temperature threshold, the anti-freeze exit condition is determined to be met.

8. The air conditioner as described in claim 3, characterized in that, The controller is also used for: Determine whether the current indoor coil temperature is above a preset third temperature threshold, and whether the current exhaust superheat is below a preset fourth temperature threshold; wherein, the first temperature threshold is less than or equal to the third temperature threshold, and the second temperature threshold is greater than or equal to the fourth temperature threshold. If so, determine whether the duration for which the current indoor coil temperature is above the third temperature threshold reaches the first time threshold, and whether the duration for which the current exhaust superheat is below the fourth temperature threshold reaches the second time threshold. If so, then the anti-freeze exit condition is met.

9. The air conditioner as described in claim 7 or 8, characterized in that, The controller is also used for: After determining that the anti-freeze exit conditions are met, the compressor speed is kept constant, and the outdoor fan speed is increased.

10. A method for preventing freezing in an air conditioner, characterized in that, An air conditioner suitable for use as described in any one of claims 1 to 9, comprising: In cooling mode, obtain the current exhaust temperature, current outdoor coil temperature, and current indoor coil temperature; The current exhaust superheat is obtained based on the current exhaust temperature and the current outdoor coil temperature. Determine whether the antifreeze entry conditions are met based on the current indoor coil temperature and the current exhaust superheat. When the anti-freeze entry conditions are met, the air conditioner is subjected to anti-freeze control by controlling the speed of the compressor and the outdoor fan.

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