Defrosting control method of air conditioner

Abstract

The invention relates to the field of air conditioners, particularly provides a defrosting control method of an air conditioner, and aims to solve the problems of frequent defrosting and low heating efficiency of an existing air conditioner. In order to achieve the purpose, the control method comprises the steps that the outdoor environment temperature and the outdoor environment humidity are obtained; based on the outdoor environment temperature and the outdoor environment humidity, the frosting restraining time and the defrosting time are determined; when the frosting condition is met, a frosting restraining strategy is executed; after the frosting inhibition time, a defrosting strategy is executed; and after the defrosting time, the defrosting strategy is quitted. According to the control method, frequent defrosting and low heating efficiency of the air conditioner can be avoided.

Description

Technical Field

[0001] The present invention relates to the field of air conditioners, and in particular provides a defrosting control method for an air conditioner. Background Art

[0002] Frost is a common problem with air conditioners operating in low-temperature winter heating mode. The accumulation of frost on the outdoor heat exchanger significantly reduces the heat exchange efficiency of the air conditioning system. This not only reduces the system's heating capacity but also increases energy consumption, impacting user comfort and increasing operating costs.

[0003] Traditional defrost strategies typically only start defrosting after the frost layer has formed a certain thickness. For example, when the outdoor heat exchanger reaches the defrost temperature, it means that the frost layer has formed a certain thickness, and the defrost mode is activated at this time. However, this leads to frequent defrost cycles and unnecessary energy waste.

[0004] Although the entire defrost cycle can be divided into a frost suppression cycle and a defrost cycle, with a frost suppression strategy implemented during the frost suppression cycle to prolong frost accumulation time and a defrost strategy implemented during the defrost cycle to improve heating efficiency, the precise end time of the frost suppression cycle and the defrost cycle cannot currently be determined, which may lead to frequent defrosting and inefficient heating.

[0005] Accordingly, the art requires a new defrost control method for an air conditioner to solve the above problems. Summary of the Invention

[0006] The present invention aims to solve the above technical problem, namely, to solve the problem of frequent defrosting and low heating efficiency of existing air conditioners.

[0007] In a first aspect, the present invention provides a defrost control method for an air conditioner, characterized in that the control method includes: obtaining the outdoor ambient temperature and the outdoor ambient humidity; determining the frost suppression time and the defrost time based on the outdoor ambient temperature and the outdoor ambient humidity; executing a frost suppression strategy when the frost conditions are met; executing a defrost strategy after the frost suppression time has passed; and exiting the defrost strategy after the defrost time has passed.

[0008] When the above technical solution is adopted, the present invention can start the frost suppression strategy to delay the formation of the frost layer and reduce the frequency of defrosting when the frosting conditions are met. Since the frost suppression time and the defrost time are determined based on the outdoor ambient temperature and the outdoor ambient humidity, the operating time of the frost suppression stage and the operating time of the defrost stage can be accurately determined, and it can be ensured that the frost layer maintains normal operation before it reaches the level that affects the heat exchange efficiency (frost suppression stage), thereby extending the heating time and saving energy. After the frost suppression time, the frost layer is too thick and affects the heating effect. At this time, the defrost stage is carried out to quickly remove the frost layer, so that the air conditioner returns to normal working state. After the defrost time, the frost layer has completely melted. At this time, in order not to affect the heating effect, it is necessary to exit the defrost strategy in time. Therefore, the above control method can avoid frequent defrosting and low heating efficiency of the air conditioner.

[0009] In the optional technical solution of the defrost control method of the above-mentioned air conditioner, the step of "determining the frost suppression time and the defrost time based on the outdoor ambient temperature and the outdoor ambient humidity" further includes: determining the total defrost time based on the outdoor ambient temperature and the outdoor ambient humidity; determining the frost suppression time and the defrost time based on the total defrost time; wherein the total defrost time is equal to the sum of the frost suppression time and the defrost time.

[0010] By adopting the above technical solution, the total defrost time can be determined more accurately, and then the frost suppression time and defrost time can be allocated based on the total defrost time, thereby minimizing energy consumption while ensuring the normal operation of the air conditioner.

[0011] In the optional technical solution of the defrost control method of the above-mentioned air conditioner, the step of "determining the total defrost time based on the outdoor ambient temperature and the outdoor ambient humidity" further includes: substituting the outdoor ambient temperature and the outdoor ambient humidity into a first formula to determine the total defrost time; the first formula is: Ttotal=fg×T+h×%Rh; wherein T is the outdoor ambient temperature, %Rh is the outdoor ambient humidity, and Ttotal is the total defrost time; f, g, and h are all constants and are positive values.

[0012] By adopting this technical solution, the total required defrost time can be calculated more scientifically and accurately, ensuring that the air conditioner can be defrosted effectively in different climate conditions. This not only improves the system's energy efficiency and operating efficiency, reducing energy consumption, but also extends the equipment's service life by avoiding excessive defrosting and ensuring its reliability in low-temperature and humid environments, thereby providing users with economic savings and a more stable user experience.

[0013] In the optional technical solution of the defrost control method of the above-mentioned air conditioner, the step of "determining the frost suppression time and defrost time based on the total defrost time" further includes: substituting the total defrost time into a second formula to determine the frost suppression time and defrost time; the second formula is: Tsuppressed==m×Ttotal, Tdeflation=(1-m)×Ttotal; wherein Ttotal is the total defrost time, Tsuppressed is the frost suppression time, Tdeflation is the defrost time, m1≤m≤m2, m1 is greater than 0.5, and m2<1.

[0014] When using the above technical solution, the time spent suppressing frost formation accounts for at least half of the total defrost time. Increasing the frost suppression time reduces the need for frequent defrosting, which consumes more energy and reduces overall energy efficiency. Furthermore, during defrost periods, the air conditioner may not be able to provide sufficient heat. Therefore, reducing the defrost time improves heating efficiency and ensures indoor comfort. Therefore, by reducing the proportion of defrost time and increasing the proportion of frost suppression time, the need for and frequency of defrosting can be reduced, ensuring stable indoor temperature.

[0015] In an optional technical solution of the above-mentioned defrost control method for an air conditioner, when T is always greater than a preset time value, m=m2; and / or when T is always less than or equal to a preset time value, m=m1.

[0016] When the total defrost time is less than or equal to the preset time value, it indicates that the outdoor ambient temperature is relatively low, the outdoor ambient humidity is relatively high, and the number of defrosts is high. In this case, a smaller value for m maximizes the defrost time, which promotes faster defrosting. When the total defrost time is greater than the preset time value, it indicates that the outdoor ambient temperature is relatively high or the humidity is relatively low, resulting in slower frost formation and, therefore, less frequent defrosting. In this case, selecting a larger value for m allows the system to maintain necessary defrost operations while reducing defrost frequency, thereby improving energy efficiency, reducing energy consumption, and ensuring long-term stable system operation.

[0017] In the optional technical solution of the defrost control method of the above-mentioned air conditioner, the control method further includes: when the frosting conditions are met, obtaining the initial opening of the throttle valve; the step of "executing the frost suppression strategy" further includes: controlling the opening of the throttle valve to increase at a valve opening rate; wherein, the valve opening rate = (preset target opening - the initial opening) / the frost suppression time, and the target opening is greater than the initial opening.

[0018] The valve opening rate is determined so that the throttle valve increases uniformly to the target opening at this rate. If the opening rate is increased too quickly, the throttle valve will already be wide open at the end of the frost suppression phase and the defrost phase will begin, effectively eliminating all heating capacity. If the opening rate is increased too slowly, the target opening will only be slightly larger than the initial opening at the end of the frost suppression phase, resulting in a poor frost suppression effect.

[0019] In the optional technical solution of the defrost control method of the above-mentioned air conditioner, the control method further includes: when the frosting conditions are met, obtaining the initial speed of the indoor fan; the step of "executing the frost suppression strategy" further includes: controlling the speed of the indoor fan to decrease at a speed change rate; wherein, the speed change rate = (the initial speed - the preset target speed) / the frost suppression time, and the initial speed is greater than the target speed.

[0020] The speed change rate is designed to uniformly reduce the indoor fan speed to the target speed. If the indoor fan speed is reduced too quickly, the indoor fan speed will drop to a very low level too early at the end of the frost suppression phase, resulting in a very low indoor air volume during the frost suppression phase and reduced heating effectiveness. If the indoor fan speed is reduced too slowly, the target speed will be only slightly lower than the initial speed at the end of the frost suppression phase, resulting in poor frost suppression effectiveness during the frost suppression phase.

[0021] In the optional technical solution of the defrost control method of the above-mentioned air conditioner, the defrost strategy is: controlling the reversal of the four-way valve to allow the outdoor heat exchanger to release heat; controlling the throttle valve opening to increase to the maximum opening; and / or controlling the indoor fan speed to decrease to the minimum speed.

[0022] When the above technical solution is adopted, the high-temperature refrigerant compressed by the compressor passes through the outdoor heat exchanger for defrosting before entering the throttle valve. Since the frosting suppression stage has slowed the accumulation of the frost layer, the defrosting stage does not take long. At this time, the throttle valve opening is increased to the maximum opening, allowing the refrigerant to enter the indoor heat exchanger almost without throttling. In this case, while ensuring system performance, it can not only ensure the defrosting of the outdoor heat exchanger, but also prevent the air at the indoor heat exchanger from being too cold. At the same time, the indoor fan speed is reduced to the minimum speed to avoid the low temperature of the blown air affecting user comfort.

[0023] In an optional technical solution of the defrost control method for the air conditioner, the control method further includes: obtaining the pipe temperature of the outdoor heat exchanger; and the frosting condition is: the pipe temperature drops to a preset critical frosting temperature.

[0024] In the optional technical solution of the defrost control method of the above-mentioned air conditioner, after "exiting the defrost strategy after the defrost time", the control method also includes: controlling the opening of the throttle valve to be reduced to an initial opening, the initial opening being the opening of the throttle valve when the frosting condition is met; and / or controlling the speed of the indoor fan to be increased to an initial speed, the initial speed being the speed of the indoor fan when the frosting condition is met. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0026] Figure 1 This is a main flow chart of the defrost control method for an air conditioner of the present invention;

[0027] Figure 2 is a possible logic diagram of the defrost control method of the air conditioner of the present invention;

[0028] Figure 3 The present invention is a possible defrost control method for an air conditioner of the present invention, which shows a curve diagram of the throttle valve opening, pipe temperature, fan speed, and compressor frequency in the heating stage and the defrost stage. DETAILED DESCRIPTION

[0029] Preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely intended to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make adjustments to these embodiments as needed to adapt to specific applications without departing from the principles of the present invention and within the scope of protection of the present invention.

[0030] In order to solve the problems of frequent defrosting and low heating efficiency of existing air conditioners. The present invention provides a defrost control method for an air conditioner, the air conditioner includes a circulation loop, and the circulation loop is provided with a compressor, an indoor heat exchanger, a throttling device and an outdoor heat exchanger connected in sequence. The throttling device can be a throttle valve or a capillary, etc., as long as it can throttle and reduce the pressure. Possibly, the air conditioner also includes a first temperature sensor, a second temperature sensor and a humidity sensor. The first temperature sensor is used to detect the outdoor ambient temperature, and the humidity sensor is used to detect the outdoor ambient humidity. The first temperature sensor and the humidity sensor can be set on the air outlet of the outdoor unit of the air conditioner (with an outdoor heat exchanger), or on the shell of the outdoor unit. The second temperature sensor is used to detect the pipe temperature of the outdoor heat exchanger, such as being set on the heat exchange pipe of the outdoor heat exchanger. The air conditioner of the present invention can also include a four-way valve, which is used to switch the flow direction of the refrigerant in the above-mentioned circulation loop, thereby realizing the switching of the evaporation and condensation functions of the indoor heat exchanger and the outdoor heat exchanger.

[0031] The defrosting control method of the air conditioner of the present invention is described below. Figure 1 As shown, it includes the following steps.

[0032] Step S100: Acquire outdoor ambient temperature and outdoor ambient humidity.

[0033] The present invention does not limit the specific method for obtaining the outdoor ambient temperature and humidity. For example, the outdoor ambient temperature can be obtained using a first temperature sensor. The outdoor ambient humidity can be obtained using a humidity sensor. Alternatively, the air conditioner can be connected to a cloud server, and the air conditioner obtains the local outdoor ambient temperature and humidity through the cloud server. As long as the outdoor ambient temperature and humidity can be obtained, these methods do not deviate from the principles of the present invention and are within the scope of protection of the present invention. It is possible that the outdoor ambient temperature and humidity are obtained during operation in heating mode.

[0034] Step S200: Determine the frost suppression time and the defrost time based on the outdoor ambient temperature and the outdoor ambient humidity.

[0035] As a possible implementation, step S200 further includes "determining a total defrost time based on the outdoor ambient temperature and the outdoor ambient humidity; and determining a frost suppression time and a defrost time based on the total defrost time." The total defrost time is equal to the sum of the frost suppression time and the defrost time. Frost suppression refers to taking measures to reduce frost formation, slowing its formation, while defrosting refers to melting it through heating or other methods.

[0036] The following describes in detail the steps for determining the total defrost time based on the outdoor ambient temperature and the outdoor ambient humidity.

[0037] The total defrost time is determined based on the outdoor ambient temperature and humidity because these two factors directly affect the rate and thickness of frost and ice formation on the outdoor heat exchanger surfaces. When the outdoor ambient temperature is near or below freezing (0°C), water vapor in the air easily condenses and forms ice on the cooler outdoor heat exchanger surfaces. At extremely low outdoor temperatures, frost can form very quickly and thickly, necessitating more frequent and longer defrost cycles. High humidity, on the other hand, means a higher water vapor content in the air, which accelerates frost and ice formation because more moisture can condense on cold surfaces. Based on these factors, a control algorithm can determine the optimal defrost time. This algorithm calculates the rate of frost formation and the expected frost thickness under current ambient conditions and then determines the total defrost time required. Alternatively, the total defrost time can be determined using a mapping table between the outdoor ambient temperature, humidity, and total defrost time, or using a pre-set first formula.

[0038] As a possible implementation, the first formula is: Ttotal = fg × T + h × %Rh; where T is the outdoor ambient temperature, %Rh is the outdoor ambient humidity, and Ttotal is the total defrost time; f, g, and h are all constants and positive values. The outdoor ambient temperature can be a specific value in degrees Celsius, the outdoor ambient humidity can be a specific value in %Rh, and the total defrost time can be a specific value in minutes. Alternatively, the total defrost time and f are in minutes, the outdoor ambient temperature is in degrees Celsius, g is in minutes / degree Celsius, %Rh is in %Rh, and h is in minutes / %Rh.

[0039] Since lower temperatures and higher humidity increase the total defrost time, the above formula satisfies this requirement. The specific values ​​of f, g, and h can be determined experimentally. For example, the values ​​of f, g, and h can be determined by reverse engineering. For example, by finding three representative outdoor temperatures, outdoor humidity, and total defrost times, and substituting them into the above formula, a linear system of equations can be obtained, from which the values ​​of f, g, and h can be derived.

[0040] The following is a detailed description of the steps for determining the frost suppression time and defrost time based on the total defrost time.

[0041] Since the total defrost time is the sum of the frost suppression time and the defrost time, the frost suppression time and the defrost time can be allocated based on the total defrost time. As a possible implementation, the total defrost time can be substituted into the second formula to determine the frost suppression time and the defrost time.

[0042] The second formula is: T suppression = m × T total, T defrost = (1-m) × T total; where T suppression is the frost suppression time, T defrost is the defrost time, m1 ≤ m ≤ m2, m1 is greater than 0.5, and m2 is less than 1. Furthermore, m1 is 0.6 and m2 is 0.8.

[0043] The above formula ensures that the frost suppression time accounts for at least half of the total defrost time. Increasing the frost suppression time can reduce the frequency of defrosting, as frequent defrosting consumes more energy and reduces overall energy efficiency. Furthermore, during defrost periods, the air conditioner may not be able to provide sufficient heat. Therefore, reducing the defrost time can improve heating efficiency and maintain indoor comfort. Therefore, by reducing the proportion of defrost time and increasing the proportion of frost suppression time, the need for and frequency of defrosting can be reduced, ensuring stable indoor temperature.

[0044] As a possible implementation, when Ttotal is greater than a preset time value, m = m2. When Ttotal is less than or equal to a preset time value, m = m1. The preset time value can be determined based on experiments or experience. For example, taking the value range of m as 0.6-0.8, for a fixed-frequency air conditioner, when Ttotal ≥ 6 minutes, m is 0.8, and when Ttotal < 6 minutes, m is 0.6; for a variable-frequency air conditioner, when Ttotal ≥ 8 minutes, m is 0.8, and when Ttotal < 8 minutes, m is 0.6. In other words, when the total defrost time is relatively long, m takes a larger value, and when the total defrost time is relatively short, m takes a smaller value.

[0045] When the total defrost time is less than or equal to the preset time value, it indicates that the outdoor ambient temperature is relatively low, the outdoor ambient humidity is relatively high, and the number of defrosts is high. In this case, a smaller value for m maximizes the defrost time, which promotes faster defrosting. When the total defrost time is greater than the preset time value, it indicates that the outdoor ambient temperature is relatively high or the humidity is relatively low, resulting in slower frost formation and, therefore, less frequent defrosting. In this case, selecting a larger value for m allows the system to maintain necessary defrost operations while reducing defrost frequency, thereby improving energy efficiency, reducing energy consumption, and ensuring long-term stable system operation.

[0046] Step S300: When the frosting condition is met, executing the frosting suppression strategy.

[0047] It is understandable that step S300 refers to executing a frost suppression strategy when the frost condition is met during operation in the heating mode. As a possible implementation method, the control method of the present invention further includes obtaining the pipe temperature of the outdoor heat exchanger, such as obtaining the real-time pipe temperature through a second temperature sensor. Possibly, the frost condition is that the pipe temperature drops to a preset critical frost temperature, and the critical frost temperature may be 0°C. Of course, as long as the outdoor heat exchanger meets the frost condition, its specific implementation method can be adjusted, for example, the outdoor ambient humidity is lower than the dew point temperature, etc. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0048] The frost suppression strategy refers to taking measures to reduce the formation of frost, so that the speed of frost formation is slowed down. For example, the throttle valve opening is controlled to increase. The speed of the indoor fan is controlled to decrease. It is understandable that the two possible implementation methods of the frost suppression strategy can be implemented together, or one of them can be implemented. When the throttle valve opening is increased, the refrigerant flow rate is increased, and the refrigerant temperature in the outdoor heat exchanger is increased. As the temperature of the outdoor heat exchanger increases, the speed of frost formation is slowed down. The speed of the indoor fan affects the flow rate of air on the surface of the indoor heat exchanger. Reducing the fan speed will reduce the air flow through the indoor heat exchanger, thereby reducing the heat exchange rate between the air and the indoor heat exchanger surface. This can reduce the heat loss on the surface of the outdoor heat exchanger, so that its temperature will not drop too quickly, and the speed of frost formation can be slowed down.

[0049] As a possible implementation, when the frosting conditions are met, the initial opening of the throttle valve is obtained. "Executing the frost suppression strategy" further includes: controlling the opening of the throttle valve to increase at a valve opening rate. Wherein, the valve opening rate = (preset target opening - initial opening) / frost suppression time, and the target opening is greater than the initial opening. Typically, the maximum common parameter for the throttle valve opening of household air conditioners is 500 steps. Based on this opening, the present invention can set the target opening between 300 and 380 steps.

[0050] The valve opening rate is determined so that the throttle valve increases uniformly to the target opening at this rate. If the opening rate is increased too quickly, the throttle valve will already be wide open at the end of the frost suppression phase and the defrost phase will begin, effectively eliminating all heating capacity. If the opening rate is increased too slowly, the target opening will only be slightly larger than the initial opening at the end of the frost suppression phase, resulting in a poor frost suppression effect.

[0051] As a possible implementation, when the frosting conditions are met, the initial speed of the indoor fan is obtained. The step of "executing the frost suppression strategy" further includes: controlling the speed of the indoor fan to decrease at a speed change rate; wherein the speed change rate = (initial speed - preset target speed) / frost suppression time, and the initial speed is greater than the target speed. Typically, the maximum speed of the indoor fan of a household air conditioner is around 1100 rpm. Based on this speed, the present invention can set the target speed between 450 rpm and 600 rpm.

[0052] The speed change rate is designed to uniformly reduce the indoor fan speed to the target speed. If the indoor fan speed is reduced too quickly, the indoor fan speed will drop to a very low level too early at the end of the frost suppression phase, resulting in a very low indoor air volume during the frost suppression phase and reduced heating effectiveness. If the indoor fan speed is reduced too slowly, the target speed will be only slightly lower than the initial speed at the end of the frost suppression phase, resulting in poor frost suppression effectiveness during the frost suppression phase.

[0053] Step S400: After the frost suppression time has elapsed, the defrost strategy is executed.

[0054] Executing a defrost strategy involves melting frost. One possible implementation involves controlling the four-way valve's direction, increasing the throttle valve's opening to its maximum, and reducing the indoor fan's speed to its minimum. It should be understood that the frost suppression time refers to the time after the frost conditions are met.

[0055] During the defrost phase, the four-way valve is controlled to reverse, swapping the functions of the indoor and outdoor heat exchangers. In this case, the outdoor heat exchanger effectively functions as a condenser, while the indoor heat exchanger functions as an evaporator. The high-temperature refrigerant, compressed by the compressor, passes through the outdoor heat exchanger for defrosting before entering the throttle valve. Since the frost suppression phase has already slowed frost accumulation, the defrost phase takes very little time. At this point, the throttle valve opening is increased to its maximum (e.g., 500 steps), allowing the refrigerant to enter the indoor heat exchanger with virtually no throttling. This ensures defrosting of the outdoor heat exchanger while also preventing overcooling of the air at the indoor heat exchanger, while maintaining system performance. Simultaneously, the indoor fan speed is reduced to its minimum (e.g., 150 rpm) to prevent the blown air from being too cold and affecting user comfort. It should be noted that the aforementioned steps of "controlling the throttle valve opening to increase to its maximum opening" and "controlling the indoor fan speed to decrease to its minimum speed" can be performed together or separately.

[0056] Furthermore, it is understood that the method for executing the defrost strategy of the present invention is not unique. As long as the frost layer can be melted, the specific control method can be adjusted. For example, the defrost strategy may include increasing the throttle valve opening to its maximum opening and reducing the indoor fan speed to its minimum speed by at least one step, without controlling the reversal of the four-way valve. Alternatively, a heating device may be provided at the outdoor heat exchanger, and executing the defrost strategy involves controlling the activation of the heating device. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0057] Step S500: After the defrost time has passed, exit the defrost strategy.

[0058] For example, when the defrost strategy is the following scheme, that is, the four-way valve is reversed, the throttle valve opening is controlled to increase to the maximum opening, and / or the indoor fan speed is controlled to decrease to the minimum speed. Exiting the defrost strategy means that the four-way valve continues to reverse, so that the indoor heat exchanger is used as a condenser and the outdoor heat exchanger is used as an evaporator, that is, the heating mode is continued. At this time, the throttle valve opening is controlled to decrease and the fan speed is controlled to increase. It can be understood that the defrost time is the time when the defrost time starts after the frost suppression time ends.

[0059] As a possible embodiment, after exiting the defrost strategy, the control method of the present invention further includes: controlling the throttle valve opening to decrease to an initial opening and / or controlling the indoor fan speed to increase to an initial speed. The initial opening is the throttle valve opening when frosting conditions are met. The initial speed is the indoor fan speed when frosting conditions are met. This allows the air conditioner to operate normally in heating mode.

[0060] As a possible implementation, Figure 2 As shown, the defrost control method of the air conditioner of the present invention includes the following steps:

[0061] Step S601: When operating in the heating mode, obtain the outdoor ambient temperature T, the outdoor ambient humidity %Rh and the outdoor heat exchanger tube temperature.

[0062] Step S602: Substitute the outdoor ambient temperature T and the outdoor ambient humidity %Rh into the formula Ttotal=fg×T+h×%Rh to obtain the total defrost time Ttotal.

[0063] Step S603: Substitute the total defrost time Ttotal into the formula Tsuppressed==m×Ttotal, Tth=(1-m)×Ttotal to obtain the frost suppression time Tsuppressed and the defrost time Tth.

[0064] Step S604: Determine whether the pipe temperature has dropped to the critical frosting temperature. If so, execute step S605; if not, return to execute step S601.

[0065] Step S605: Control the opening of the throttle valve to increase at the valve opening rate, and control the speed of the indoor fan to decrease at the speed change rate.

[0066] Step S606: Determine whether the frost suppression time has elapsed. If yes, execute step S607; if no, return to step S605.

[0067] Step S607: Control the four-way valve to switch direction.

[0068] Step S608: Control the throttle valve opening to increase to the maximum opening, and control the indoor fan speed to decrease to the minimum speed.

[0069] Step S609: Determine whether the defrosting time has elapsed. If so, execute step S610; if not, return to step S608.

[0070] Step S610: Control the four-way valve to continue reversing; control the opening of the throttle valve to decrease to the initial opening, and control the speed of the indoor fan to increase to the initial speed.

[0071] Those skilled in the art will appreciate that the air conditioner described above also includes some other well-known structures, such as a processor, a controller, and a memory. The memory includes, but is not limited to, random access memory, flash memory, read-only memory, programmable read-only memory, volatile memory, non-volatile memory, serial memory, parallel memory, or registers. The processor includes, but is not limited to, CPLD / FPGA, DSP, ARM processor, MIPS processor, etc. To unnecessarily obscure the embodiments of the present disclosure, these well-known structures are not shown in the drawings.

[0072] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A defrost control method for an air conditioner, characterized in that: The control method includes: Get outdoor ambient temperature and outdoor ambient humidity; Determining a frost suppression time and a defrost time based on the outdoor ambient temperature and the outdoor ambient humidity; When the frost conditions are met, the frost suppression strategy is executed; After the frost suppression time has elapsed, executing a defrost strategy; After the defrost time has passed, the defrost strategy is exited.

2. The defrost control method for an air conditioner according to claim 1, wherein: The step of “determining the frost suppression time and the defrost time based on the outdoor ambient temperature and the outdoor ambient humidity” further includes: determining a total defrost time based on the outdoor ambient temperature and the outdoor ambient humidity; Determining a frost suppression time and a defrost time based on the total defrost time; The total defrost time is equal to the sum of the frost suppression time and the defrost time.

3. The defrost control method for an air conditioner according to claim 2, wherein: The step of “determining the total defrost time based on the outdoor ambient temperature and the outdoor ambient humidity” further includes: Substituting the outdoor ambient temperature and the outdoor ambient humidity into a first formula to determine a total defrost time; The first formula is: Ttotal=fg×T+h×%Rh; Wherein, T is the outdoor ambient temperature, %Rh is the outdoor ambient humidity, Ttotal is the total defrost time; f, g, and h are all constants and are positive values.

4. The defrost control method for an air conditioner according to claim 2, wherein: The step of “determining the frosting suppression time and the defrosting time based on the total defrosting time” further includes: Substituting the total defrost time into a second formula to determine the frost suppression time and defrost time; The second formula is: T = m × T, T = (1-m) × T; Among them, Ttotal is the total defrost time, Tinhibit is the frost suppression time, Ttrans is the defrost time, m1≤m≤m2, m1 is greater than 0.5, and m2 is less than 1.

5. The defrost control method for an air conditioner according to claim 4, characterized in that: When T is always greater than the preset time value, m=m2; and / or When Ttotal is less than or equal to the preset time value, m=m1.

6. The defrost control method for an air conditioner according to claim 1, wherein: The control method further includes: When the frosting condition is met, the initial opening of the throttle valve is obtained; The step of "executing the frost suppression strategy" further includes: Control the opening of the throttle valve to increase at the valve opening rate; The valve opening rate=(preset target opening-the initial opening) / the frost suppression time, and the target opening is greater than the initial opening.

7. The defrost control method for an air conditioner according to claim 1, wherein: The control method further includes: When the frosting condition is met, the initial speed of the indoor fan is obtained; The step of "executing the frost suppression strategy" further includes: controlling the speed of the indoor fan to decrease at a speed change rate; The speed change rate=(the initial speed-the preset target speed) / the frosting suppression time, and the initial speed is greater than the target speed.

8. The defrost control method for an air conditioner according to claim 1, wherein: The defrost strategy is: Control the reversing direction of the four-way valve to release heat from the outdoor heat exchanger; Increase the throttle valve opening to its maximum opening; and / or Control the indoor fan speed to the minimum speed.

9. The defrost control method for an air conditioner according to claim 1, wherein: The control method further includes: Get the tube temperature of the outdoor heat exchanger; The frosting conditions are: The pipe temperature is reduced to a preset critical frosting temperature.

10. The defrost control method for an air conditioner according to claim 8, wherein: After "exiting the defrost strategy after the defrost time has passed", the control method further includes: controlling the opening of the throttle valve to decrease to an initial opening, wherein the initial opening is the opening of the throttle valve when the frosting condition is satisfied; and / or The indoor fan speed is controlled to increase to an initial speed, where the initial speed is the speed of the indoor fan when the frosting condition is met.

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