Defrosting control method for heat pump system

Abstract

The present application relates to the technical field of heat pump, and particularly provides a frost control method of heat pump system, aiming at solving the problem of low heat exchange efficiency of the existing heat pump system caused by frost. For this purpose, the heat pump system comprises an evaporator and a heat exchange fan arranged near the evaporator, the evaporator comprises a plurality of heat exchange components arranged in parallel, and a refrigerant flow path can flow through the plurality of heat exchange components in sequence; the heat pump system of the present application selectively controls the heat pump system to perform frost control operation by acquiring the front end temperature, middle temperature and end temperature of the flow path of the evaporator located on the windward side and the back leeward side, and the outdoor dew point temperature, the present application can more accurately determine whether the evaporator will frost by acquiring the temperature at different positions of the evaporator, so as to perform frost control operation before the evaporator frosts, effectively prevent the evaporator from forming frost layer, and effectively ensure the heat exchange efficiency of the heat pump system, and improve the user experience.

Description

Technical Field

[0001] This invention relates to the field of heat pump technology, and specifically provides a defrosting control method for heat pump systems. Background Technology

[0002] When a heat pump system is operating in heating mode, the temperature on the windward side is higher. After passing through the first row of heat exchange components, the air temperature drops significantly. Furthermore, because the refrigerant flows in the same direction as the air during heating, the resulting pressure drop in the refrigerant causes its temperature to gradually decrease as it flows through the heat exchange components. Therefore, the rear part of the leeward side, at the rear of the last row of heat exchange components, has the lowest temperature and is most prone to frosting. However, frosting on the heat exchange components not only significantly reduces their heat exchange efficiency but also causes the airflow velocity on the surface of the heat exchange components to decrease due to the presence of frost.

[0003] Accordingly, there is a need in the art for a new defrosting control method for heat pump systems to solve the above-mentioned technical problems. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned technical problems, namely, to solve the problem that existing heat pump systems are prone to low heat exchange efficiency due to frost formation.

[0005] This invention provides a defrosting control method for a heat pump system. The heat pump system includes an evaporator and a heat exchange fan disposed near the evaporator. The evaporator includes multiple heat exchange components arranged in parallel, and a refrigerant flow path can sequentially flow through the multiple heat exchange components. The defrosting control method includes: acquiring the front end temperature, middle temperature, and end temperature of the evaporator flow path, as well as the outdoor dew point temperature; selectively controlling the heat pump system to perform defrosting operation based on the front end temperature, middle temperature, and end temperature of the evaporator flow path, and the outdoor dew point temperature; wherein the front end of the evaporator flow path is located on the windward side, and the end of the evaporator flow path is located on the leeward side.

[0006] In the preferred embodiment of the above-mentioned defrosting control method, the step of "selectively controlling the heat pump system to perform defrosting operation based on the evaporator's flow path front-end temperature, flow path middle temperature, flow path end temperature, and outdoor dew point temperature" specifically includes: comparing the minimum value among the evaporator's flow path front-end temperature, flow path middle temperature, and flow path end temperature with the outdoor dew point temperature; and selectively controlling the heat pump system to perform defrosting operation based on the comparison result of the minimum value among the evaporator's flow path front-end temperature, flow path middle temperature, and flow path end temperature with the outdoor dew point temperature.

[0007] In the preferred embodiment of the above-mentioned defrosting control method, the step of "selectively controlling the heat pump system to perform defrosting operation based on the comparison result of the minimum value among the front-end temperature, middle temperature, and end temperature of the evaporator flow path and the outdoor dew point temperature" specifically includes: if the minimum value among the front-end temperature, middle temperature, and end temperature of the evaporator flow path is less than the outdoor dew point temperature, then further comparing the outdoor dew point temperature with a first preset temperature; and selectively controlling the heat pump system to perform defrosting operation based on the comparison result of the outdoor dew point temperature and the first preset temperature.

[0008] In the preferred embodiment of the above-mentioned defrosting control method, the step of "selectively controlling the heat pump system to perform defrosting operation based on the comparison result of the outdoor dew point temperature and the first preset temperature" includes: if the outdoor dew point temperature is greater than the first preset temperature, then further comparing the minimum value among the evaporator's flow path front end temperature, flow path middle temperature, and flow path end temperature with a second preset temperature; selectively controlling the heat pump system to perform defrosting operation based on the comparison result of the minimum value among the evaporator's flow path front end temperature, flow path middle temperature, and flow path end temperature with the second preset temperature; wherein, the second preset temperature is less than the first preset temperature.

[0009] In the preferred embodiment of the above-mentioned defrosting control method, the step of "selectively controlling the heat pump system to perform defrosting operation based on the comparison result of the minimum value among the flow path front end temperature, flow path middle temperature and flow path end temperature of the evaporator and the second preset temperature" specifically includes: if the minimum value among the flow path front end temperature, flow path middle temperature and flow path end temperature of the evaporator is continuously less than the second preset temperature for a first preset time, then the heat pump system is controlled to perform defrosting operation.

[0010] In the preferred embodiment of the above-mentioned anti-frost control method, the first preset temperature is 0℃ and the second preset temperature is -1℃.

[0011] In the preferred embodiment of the above-mentioned defrosting control method, the step of "selectively controlling the heat pump system to perform defrosting operation based on the comparison result of the outdoor dew point temperature and the first preset temperature" further includes: if the outdoor dew point temperature is less than or equal to the first preset temperature, then further obtaining the duration for which the minimum value among the flow path front end temperature, flow path middle temperature, and flow path end temperature of the evaporator is continuously less than the first preset temperature; if the duration for which the minimum value among the flow path front end temperature, flow path middle temperature, and flow path end temperature of the evaporator is continuously less than the first preset temperature reaches a second preset duration, then controlling the heat pump system to perform defrosting operation.

[0012] In the preferred embodiment of the above-mentioned defrosting control method, the step of "controlling the heat pump system to perform defrosting operation" specifically includes: controlling the heat exchange fan to reverse and increasing the speed of the heat exchange fan.

[0013] In the preferred embodiment of the above-mentioned defrosting control method, before performing the step of "controlling the heat exchange fan to reverse and increasing the speed of the heat exchange fan", the defrosting control method further includes: determining the increase range of the speed of the heat exchange fan based on the difference between the first preset temperature and the minimum value among the temperature at the front end of the flow path, the temperature in the middle of the flow path, and the temperature at the end of the flow path of the evaporator.

[0014] In the preferred embodiment of the above-mentioned defrosting control method, during the defrosting operation of the heat pump system, the defrosting control method further includes: acquiring the front end temperature, middle part temperature, and end temperature of the evaporator flow path again; if the minimum value among the front end temperature, middle part temperature, and end temperature of the evaporator flow path acquired again is greater than the first preset temperature, then the heat pump system is controlled to no longer perform the defrosting operation.

[0015] When adopting the above technical solution, the heat pump system of the present invention includes an evaporator and a heat exchange fan disposed near the evaporator. The evaporator includes multiple heat exchange components arranged in parallel, and the refrigerant flow path can flow through the multiple heat exchange components in sequence. The heat pump system of the present invention selectively controls the heat pump system to perform defrosting operation by acquiring the temperature at the front end of the flow path on the windward side, the temperature at the middle of the flow path, the temperature at the end of the flow path on the leeward side, and the outdoor dew point temperature. The present invention can more accurately determine whether the evaporator will frost by acquiring the temperature at different locations of the evaporator, so as to perform defrosting operation before the evaporator frosts, effectively preventing the formation of frost on the evaporator, thereby effectively ensuring the heat exchange efficiency of the heat pump system and improving the user experience. Attached Figure Description

[0016] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0017] Figure 1 This is a flowchart of the main steps of the frost suppression control method of the present invention;

[0018] Figure 2 This is a flowchart illustrating the specific steps of a preferred embodiment of the frost control method of the present invention. Detailed Implementation

[0019] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of 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 can make adjustments as needed to adapt to specific applications. For example, the heat pump system described in this invention can be a residential heat pump system or a commercial heat pump system, a direct-heating heat pump system or a circulating heat pump system; these are not limiting. Those skilled in the art can define the application of the defrosting control method of the present invention according to actual usage requirements. Such changes in the application do not deviate from the basic principles of the present invention and fall within the scope of protection of the present invention.

[0020] It should be noted that, in the description of this preferred embodiment, unless otherwise explicitly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as limiting the present invention. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0021] Furthermore, it should be noted that although the steps of the anti-frost control method of the present invention are described in a specific order in the description of the present invention, these orders are not restrictive. Without departing from the basic principles of the present invention, those skilled in the art can perform the steps in different orders.

[0022] Specifically, the heat pump system of the present invention includes a refrigerant flow path, on which a compressor, a throttling component, and two heat exchangers are disposed. One of the two heat exchangers is used as a condenser, and the other of the two heat exchangers is used as an evaporator. Refrigerant for heat exchange flows through the refrigerant flow path. The evaporator includes multiple heat exchange components arranged in parallel, and the refrigerant flow path can flow through the multiple heat exchange components in sequence. The heat pump system also includes a heat exchange fan, which is disposed near the evaporator.

[0023] It should be noted that the present invention does not impose any restrictions on the specific structure of the heat exchange component and the heat exchange fan. The heat exchange component can be a coil or a plate-tube structure, and the heat exchange fan can be a centrifugal fan or a turbine fan. These are not limiting, and those skilled in the art can set them according to the actual situation.

[0024] Furthermore, a four-way valve is also provided in the refrigerant flow path. When the four-way valve switches, it can control the reverse circulation of the refrigerant in the refrigerant flow path, so that the heat pump system can switch between cooling and heating modes. Those skilled in the art will understand that the evaporator is used as an evaporator in heating mode and as a condenser in cooling mode. The defrosting control method of this invention targets the heat exchanger acting as an evaporator. In addition, it should be noted that this invention does not impose any limitations on the specific structure of the heat pump system; those skilled in the art can set it according to actual usage requirements.

[0025] Furthermore, the heat pump system also includes a temperature sensor, a dew point meter, and a controller. The temperature sensor is used to acquire the temperature at the front end, middle, and end of the flow path of the evaporator. The dew point meter is used to acquire the outdoor dew point temperature. Those skilled in the art will understand that the present invention does not impose any restrictions on the specific structure, specific location, or number of the temperature sensor and the dew point meter. Those skilled in the art can set them according to the actual situation.

[0026] The controller can acquire the temperatures at the front end, middle, and rear end of the evaporator flow path detected by the temperature sensor, and also the outdoor dew point temperature detected by the dew point meter. The controller can also control the operating status of the heat pump system, such as controlling the operating status of the heat exchange fan, etc., which are not limiting. Those skilled in the art will understand that the present invention does not impose any limitations on the specific structure and model of the controller, and the controller can be either the original controller of the heat pump system or a controller separately set up to implement the defrosting control method of the present invention. Those skilled in the art can customize the structure and model of the controller according to actual usage requirements.

[0027] First refer to Figure 1 , Figure 1 This is a flowchart illustrating the main steps of the frost control method of the present invention. Figure 1 As shown, based on the heat pump system described in the above embodiments, the defrosting control method of the present invention mainly includes the following steps:

[0028] S1: Obtain the temperature at the front end of the evaporator flow path, the temperature in the middle of the flow path, the temperature at the end of the flow path, and the outdoor dew point temperature;

[0029] S2: Selectively control the heat pump system to perform defrosting operation based on the temperature at the front end, middle and end of the evaporator flow path and the outdoor dew point temperature.

[0030] First, in step S1, the controller obtains the temperature at the front end, middle and end of the evaporator flow path through the temperature sensor, and obtains the outdoor dew point temperature through the dew point meter.

[0031] It should be noted that the present invention does not impose any restrictions on the specific acquisition method and timing of the evaporator flow path front end temperature, flow path middle temperature, flow path end temperature, and outdoor dew point temperature. The controller can acquire the temperature in real time or at certain intervals, which are not restrictive. Those skilled in the art can set the temperature according to the actual situation.

[0032] Next, in step S2, the controller selectively controls the heat pump system to perform defrosting operation based on the temperature at the front end, middle, and end of the evaporator's flow path, as well as the outdoor dew point temperature. Specifically, the front end of the evaporator's flow path is located on the windward side, and the end of the evaporator's flow path is located on the leeward side, so as to accurately determine whether the heat pump system needs defrosting by observing the temperature conditions at different locations of the evaporator.

[0033] It should be noted that the present invention does not impose any restrictions on the specific execution logic of step S2. For example, the controller may selectively control the heat pump system to perform defrosting operation based on the comparison results of the front end temperature, middle temperature, and end temperature of the evaporator flow path with the outdoor dew point temperature. This is not a limitation.

[0034] Furthermore, it should be noted that the present invention does not impose any restrictions on the specific execution of the defrosting operation. It may be to increase the evaporation temperature of the evaporator or to adjust the operating frequency of the compressor. These are not limiting, and those skilled in the art can set them according to the actual situation.

[0035] See next Figure 2 , Figure 2 This is a flowchart illustrating the specific steps of a preferred embodiment of the frost control method of the present invention. Figure 2 As shown, based on the heat pump system described in the above embodiments, the defrosting control method of the preferred embodiment of the present invention includes the following steps:

[0036] S101: Obtain the temperature at the front end of the evaporator flow path, the temperature in the middle of the flow path, the temperature at the end of the flow path, and the outdoor dew point temperature;

[0037] S102: Compare the minimum value of the evaporator's flow path front temperature, flow path middle temperature, and flow path end temperature with the outdoor dew point temperature;

[0038] S103: If the minimum value among the evaporator flow path front end temperature, flow path middle temperature and flow path end temperature is less than the outdoor dew point temperature, then the outdoor dew point temperature is further compared with the first preset temperature.

[0039] S104: If the outdoor dew point temperature is greater than the first preset temperature, then the minimum value of the evaporator flow path front end temperature, flow path middle temperature and flow path end temperature is further compared with the second preset temperature.

[0040] S105: If the minimum value of the temperature at the front end of the evaporator flow path, the temperature in the middle of the flow path, and the temperature at the end of the flow path is lower than the second preset temperature for a duration that reaches the first preset duration, then control the heat exchange fan to reverse and increase the speed of the heat exchange fan.

[0041] S106: If the outdoor dew point temperature is less than or equal to the first preset temperature, then further obtain the duration for which the minimum value among the evaporator flow path front end temperature, flow path middle temperature and flow path end temperature is continuously less than the first preset temperature.

[0042] S107: If the minimum value of the temperature at the front end of the evaporator flow path, the temperature in the middle of the flow path, and the temperature at the end of the flow path is lower than the first preset temperature for a duration that reaches the second preset duration, then control the heat exchange fan to reverse and increase the speed of the heat exchange fan.

[0043] S108: Obtain the temperature at the beginning, middle, and end of the evaporator flow path again;

[0044] S109: If the minimum value among the evaporator flow path front end temperature, flow path middle temperature and flow path end temperature obtained again is greater than the first preset temperature, then control the heat exchange fan to rotate in the forward direction and control the speed of the heat exchange fan to no longer increase.

[0045] First, in step S101, the controller obtains the temperature at the front end, middle, and end of the evaporator's flow path through the temperature sensor, and obtains the outdoor dew point temperature through the dew point meter.

[0046] It should be noted that the present invention does not impose any restrictions on the specific acquisition method and timing of the evaporator flow path front end temperature, flow path middle temperature, flow path end temperature, and outdoor dew point temperature. The controller can acquire the temperature in real time or at certain intervals, which are not restrictive. Those skilled in the art can set the temperature according to the actual situation.

[0047] Next, the controller selectively controls the heat pump system to perform defrosting operation based on the temperature at the front end, middle, and end of the evaporator's flow path, as well as the outdoor dew point temperature, so as to effectively ensure the heating capacity and heat exchange efficiency of the heat pump system. Specifically, the front end of the evaporator's flow path is located on the windward side, and the end of the evaporator's flow path is located on the leeward side, so as to accurately determine whether the heat pump system needs defrosting by observing the temperature conditions at different locations of the evaporator.

[0048] It should be noted that this invention does not impose any restrictions on the specific execution of the defrosting operation; those skilled in the art can set it according to actual conditions. Existing heat pump systems use hot gas bypass, increasing the opening of the electronic expansion valve, adjusting the compressor frequency, or increasing the speed of the heat exchange fan to suppress frost formation. However, the essence of these methods is to increase the temperature of the refrigerant entering the heat exchange components of the heat pump system to suppress frost formation. Although the purpose of frost suppression is achieved, the heating capacity of the heat pump system is reduced, resulting in a poor user experience. In this preferred embodiment, controlling the heat pump system to perform the defrosting operation involves the controller controlling the heat exchange fan to reverse and increase its speed. Based on this setting, this invention, by utilizing the change in airflow direction, alters the inlet direction of the high-temperature air, effectively suppressing frost formation on the leeward side of the evaporator and making the airflow direction counter-current to the overall refrigerant flow direction, effectively improving the heat exchange effect of the heat pump system, thereby ensuring that the indoor air outlet temperature does not fluctuate excessively and improving the user experience.

[0049] Furthermore, it should be noted that the present invention does not impose any restrictions on the specific execution logic of the above steps. For example, the controller may selectively control the heat pump system to perform defrosting operation based on the comparison results of the front end temperature, middle temperature, and end temperature of the evaporator flow path with the outdoor dew point temperature. This is not restrictive, and those skilled in the art can set it according to the actual situation.

[0050] Preferably, in step S102, the controller compares the minimum value of the evaporator's flow path front end temperature, flow path middle temperature, and flow path end temperature with the outdoor dew point temperature.

[0051] Next, the controller selectively controls the heat pump system to perform a defrost operation based on a comparison between the minimum of the evaporator's flow path front-end temperature, flow path middle temperature, and flow path end temperature and the outdoor dew point temperature. Specifically, in step S103, if the minimum of the evaporator's flow path front-end temperature, flow path middle temperature, and flow path end temperature is less than the outdoor dew point temperature, indicating a risk of frost formation on the evaporator, the controller further compares the outdoor dew point temperature with a first preset temperature, and selectively controls the heat pump system to perform a defrost operation based on the comparison result. This allows for further determination of whether the evaporator will frost based on the outdoor dew point temperature, and thus, whether the heat pump system needs to perform a defrost operation.

[0052] Specifically, in step S104, if the outdoor dew point temperature is greater than the first preset temperature, it indicates that the risk of the evaporator frosting is low. Then, the controller further compares the minimum value of the front end temperature, middle temperature, and end temperature of the evaporator with the second preset temperature, wherein the second preset temperature is less than the first preset temperature, to further determine whether the evaporator will frost, so as to ensure the heat exchange effect of the heat pump system.

[0053] Next, the controller selectively controls the heat pump system to perform a defrost operation based on a comparison between the minimum value of the evaporator's flow path front-end temperature, flow path middle temperature, and flow path end temperature and the second preset temperature. It should be noted that this invention does not impose any limitations on the specific comparison method described above; it can be a magnitude comparison or a ratio comparison, neither of which is restrictive. Furthermore, it should be noted that this invention does not impose any limitations on the specific setting values ​​of the first and second preset temperatures; preferably, the first preset temperature is 0°C and the second preset temperature is -1°C, so as to accurately determine the possibility of frost formation on the evaporator and execute the defrost operation in a timely manner; it can also effectively avoid the heat pump system repeatedly entering the defrost mode, ensuring the normal operation of the heat pump system.

[0054] Specifically, in step S105, if the minimum value among the front end temperature, middle temperature, and end temperature of the evaporator flow path is lower than the second preset temperature for a duration equal to the first preset duration, it indicates that the temperature at a certain location in the evaporator has been lower than -1°C for too long, and the probability of frost formation on the evaporator is relatively high. In this case, the controller controls the heat pump system to perform a defrosting operation, that is, the controller controls the heat exchange fan to reverse and increase the speed of the heat exchange fan to effectively prevent frost formation on the evaporator, thereby effectively ensuring the heat exchange effect of the heat pump system.

[0055] Furthermore, in step S106, if the outdoor dew point temperature is less than or equal to the first preset temperature (0°C), it indicates that the outdoor dew point temperature is too low and the evaporator is likely to frost. In this case, the controller further obtains the duration for which the minimum value among the front end temperature, middle temperature, and end temperature of the evaporator flow path is continuously less than the first preset temperature, so as to further determine the location of the lowest temperature of the evaporator.

[0056] Next, in step S107, if the minimum value among the front end temperature, middle temperature, and end temperature of the evaporator flow path is lower than the first preset temperature for a duration that reaches the second preset duration, it indicates that the temperature at a certain location in the evaporator has been lower than 0°C for too long, and the probability of the evaporator frosting is relatively high. In this case, the controller controls the heat exchange fan to reverse and increases the speed of the heat exchange fan to effectively prevent the evaporator from frosting, thereby effectively ensuring the heat exchange effect of the heat pump system.

[0057] It should be noted that the present invention does not impose any restrictions on the specific setting values ​​of the first preset duration and the second preset duration. Those skilled in the art can set them according to the actual usage of the user or the actual operation of the heat pump system, which are not restrictive.

[0058] Furthermore, it should be noted that the present invention does not impose any limitation on the specific increase in the rotational speed of the heat exchange fan; those skilled in the art can set it according to actual conditions. As a preferred embodiment, the controller determines the increase in the rotational speed of the heat exchange fan based on the difference between the first preset temperature and the minimum value among the temperatures at the front end, middle, and end of the evaporator's flow path. Specifically, the increase in the rotational speed of the heat exchange fan is directly proportional to the magnitude of the difference; that is, the larger the difference, the greater the increase in the rotational speed of the heat exchange fan, resulting in a higher rotational speed, thus effectively suppressing frost formation on the evaporator. Conversely, the smaller the difference, the less the increase in the rotational speed of the heat exchange fan, thereby effectively reducing the operating energy consumption of the heat pump system while effectively suppressing frost formation on the evaporator.

[0059] In this specific embodiment, more preferably, in step S108, the controller again acquires the front-end temperature, middle-end temperature, and end-end temperature of the evaporator's flow path. Of course, the actual timing of acquiring these temperatures is not limiting; those skilled in the art can set it according to actual conditions. Preferably, the controller acquires the front-end temperature, middle-end temperature, and end-end temperature of the evaporator's flow path in real time during the defrosting operation of the heat pump system, in order to promptly determine the temperature status at various locations of the evaporator.

[0060] Next, in step S109, if the minimum value among the front end temperature, middle temperature, and end temperature of the evaporator flow path is greater than the first preset temperature, it indicates that there is no risk of frost formation on the evaporator at this time. Then, the controller controls the heat pump system to stop performing the defrosting operation, that is, controls the hot air fan to rotate in the forward direction and controls the speed of the heat exchange fan to stop increasing, so that the heat pump system returns to normal heating mode.

[0061] The technical solution of the present invention has been described above with reference to 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 can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A frost control method for a heat pump system, characterized by, The heat pump system includes an evaporator and a heat exchange fan disposed near the evaporator. The evaporator includes multiple heat exchange components arranged in parallel, and a refrigerant flow path can sequentially flow through the multiple heat exchange components. The defrosting control method includes: The temperatures at the beginning, middle, and end of the flow path of the evaporator, as well as the outdoor dew point temperature, are obtained. Based on the temperatures at the front end, middle, and rear end of the evaporator's flow path and the outdoor dew point temperature, the heat pump system is selectively controlled to perform defrosting operations, the steps of which include: The minimum value among the evaporator's flow path inlet temperature, flow path middle temperature, and flow path outlet temperature is compared with the outdoor dew point temperature. Based on the comparison result of the minimum value among the evaporator's flow path inlet temperature, flow path middle temperature, and flow path outlet temperature and the outdoor dew point temperature, the heat pump system is selectively controlled to perform defrost operation, the steps of which include: If the minimum value among the evaporator's flow path front-end temperature, flow path middle temperature, and flow path end temperature is less than the outdoor dew point temperature, then the outdoor dew point temperature is further compared with a first preset temperature; based on the comparison result between the outdoor dew point temperature and the first preset temperature, the heat pump system is selectively controlled to perform defrosting operation, the steps of which include: If the outdoor dew point temperature is less than or equal to the first preset temperature, then the duration for which the minimum value among the evaporator's flow path front end temperature, flow path middle temperature, and flow path end temperature is continuously less than the first preset temperature is further obtained; if the duration for which the minimum value among the evaporator's flow path front end temperature, flow path middle temperature, and flow path end temperature is continuously less than the first preset temperature reaches a second preset duration, then the heat pump system is controlled to perform a defrosting operation. The steps of "controlling the heat pump system to perform defrosting operation" specifically include: Control the heat exchange fan to reverse and increase the speed of the heat exchange fan; The front end of the evaporator's flow path is located on the windward side, and the end of the evaporator's flow path is located on the leeward side.

2. The frost control method according to claim 1, wherein The step of "selectively controlling the heat pump system to perform defrosting operation based on the comparison result between the outdoor dew point temperature and the first preset temperature" includes: If the outdoor dew point temperature is greater than the first preset temperature, then the minimum value among the front end temperature, middle part temperature and end temperature of the evaporator flow path is further compared with the second preset temperature. Based on the comparison between the minimum value of the flow path front end temperature, flow path middle temperature and flow path end temperature of the evaporator and the second preset temperature, the heat pump system is selectively controlled to perform defrosting operation; The second preset temperature is lower than the first preset temperature.

3. The frost suppression control method according to claim 2, characterized in that, The step of "selectively controlling the heat pump system to perform defrosting operation based on the comparison result of the minimum value among the front-end temperature, middle temperature, and end temperature of the evaporator flow path and the second preset temperature" specifically includes: If the minimum value among the front-end temperature, middle temperature, and end temperature of the evaporator flow path remains below the second preset temperature for a duration equal to a first preset duration, then the heat pump system is controlled to perform a defrosting operation.

4. The frost suppression control method according to claim 2, characterized in that, The first preset temperature is 0℃, and the second preset temperature is -1℃.

5. The frost suppression control method according to claim 1, characterized in that, Before performing the step of "controlling the heat exchange fan to reverse and increasing the speed of the heat exchange fan", the defrosting control method further includes: The increase in the rotational speed of the heat exchange fan is determined based on the difference between the first preset temperature and the minimum value among the temperatures at the front end, middle, and end of the evaporator flow path.

6. The frost control method according to any one of claims 1 to 4, characterized in that, During the defrosting operation of the heat pump system, the defrosting control method further includes: The temperatures at the beginning, middle, and end of the flow path of the evaporator are obtained again. If the minimum value among the front end temperature, middle temperature, and end temperature of the evaporator flow path is obtained again is greater than the first preset temperature, then the heat pump system is controlled to stop performing the defrosting operation.

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