Control method of air conditioner

Abstract

The invention discloses a control method of an air conditioner, and belongs to the technical field of air treatment. The air conditioner comprises a compressor, an outdoor heat exchanger, a first electronic expansion valve, a first indoor heat exchanger, a second electronic expansion valve and a second indoor heat exchanger. A fresh air outlet of the fresh air module can communicate with the indoor air return opening; when the air conditioner runs, fresh air flows through the second indoor heat exchanger and then flows through the first indoor heat exchanger from the indoor air return opening. The control method comprises the dehumidification step of controlling the opening degree of a second electronic expansion valve to adjust the refrigerating temperature of a second indoor heat exchanger so that fresh air can be cooled and dehumidified when flowing through the second indoor heat exchanger, and the dehumidification step of controlling the opening degree of a first electronic expansion valve or the frequency of a compressor to adjust the heating temperature of a first indoor heat exchanger so that the fresh air can be cooled and dehumidified when flowing through the second indoor heat exchanger. And the temperature fine adjustment step is used for increasing the temperature of the cooled fresh air when the cooled fresh air flows through the first indoor heat exchanger. According to the control method of the air conditioner, fresh air dehumidification can be achieved.

Description

Technical Field

[0001] The present application relates to the technical field of air treatment, and in particular to a control method for an air conditioner. Background Art

[0002] Some air conditioners have a fresh air function, which improves the freshness of indoor air by sending outdoor air into the room. In spring and summer, the southern region and some coastal areas will experience weather phenomena such as the return of the south wind and the plum rain season. Although the air temperature is relatively moderate, the humidity is very high. The air conditioner introduces this high-humidity fresh air into the room, which will cause people's comfort to be extremely poor.

[0003] In the related art, a dehumidification wheel is added to the fresh air module so as to absorb moisture from the fresh air by the dehumidification wheel to achieve the purpose of dehumidifying the fresh air.

[0004] However, this dehumidification method requires major changes to the fresh air module and the air conditioning structure. Therefore, it is necessary to add a fresh air dehumidification function to the air conditioner from the perspective of control logic to reduce changes to the air conditioner structure. Summary of the invention

[0005] The present application provides a control method for an air conditioner, which can achieve fresh air dehumidification.

[0006] In one aspect of the present application, an air conditioner comprises: a refrigerant circuit in which a compressor, an outdoor heat exchanger, a first electronic expansion valve, a first indoor heat exchanger, a second electronic expansion valve and a second indoor heat exchanger are connected in series; a fresh air module, wherein a fresh air outlet of the fresh air module can be connected to an indoor return air outlet of the air conditioner so that the fresh air introduced by the fresh air module flows to the indoor return air outlet; when the air conditioner is in operation, the fresh air flows from the indoor return air outlet first through the second indoor heat exchanger and then through the first indoor heat exchanger;

[0007] The control method of the air conditioner includes: a dehumidification step of controlling the opening of the second electronic expansion valve according to the temperature of the second indoor heat exchanger and the relative humidity of the indoor return air to adjust the cooling temperature of the second indoor heat exchanger so that the fresh air is cooled and dehumidified when flowing through the second indoor heat exchanger, and a fine temperature adjustment step of controlling the opening of the first electronic expansion valve or the frequency of the compressor according to the difference between the indoor return air temperature and the indoor target temperature or the difference between the indoor return air temperature and the outdoor ambient temperature to adjust the heating temperature of the first indoor heat exchanger so that the cooled fresh air is heated when flowing through the first indoor heat exchanger;

[0008] In some embodiments, the air conditioner can operate at least one of the following fresh air slight cooling and dehumidification mode, fresh air non-cooling and dehumidification mode, and fresh air slight heating and dehumidification mode;

[0009] In the fresh air micro-cooling and dehumidification mode, the micro-temperature adjustment step includes determining the difference between the indoor return air temperature and the indoor target temperature. When the difference is less than the lower limit of the preset temperature difference interval, the opening of the first electronic expansion valve is increased; when the difference is greater than the upper limit of the preset temperature difference interval, the opening of the first electronic expansion valve is reduced.

[0010] In the fresh air non-cooling dehumidification mode, the fine temperature adjustment step includes controlling the first electronic expansion valve to be fully opened; judging the difference between the indoor return air temperature and the outdoor ambient temperature, and when the difference is less than the lower limit of the preset temperature difference interval, increasing the frequency of the compressor; when the difference is greater than the upper limit of the preset temperature difference interval, reducing the frequency of the compressor;

[0011] In the fresh air micro-heating dehumidification mode, the fine temperature adjustment step includes controlling the first electronic expansion valve to be fully open; judging the difference between the indoor return air temperature and the indoor target temperature, and when the difference is less than the lower limit of the preset temperature difference range, increasing the frequency of the compressor; when the difference is greater than the upper limit of the preset temperature difference range, reducing the frequency of the compressor.

[0012] In some embodiments, when entering the fresh air slight cooling and dehumidification mode, the second electronic expansion valve is opened at an initial opening degree a. 21 Open;

[0013] When entering the fresh air non-cooling dehumidification mode, the second electronic expansion valve is lower than a 21 The initial opening a 22 Open;

[0014] When entering the fresh air slight heating and dehumidification mode, the second electronic expansion valve is lower than a 22 The initial opening a 23 Turn on.

[0015] In some embodiments, when entering the fresh air non-cooling dehumidification mode, the compressor is controlled to operate at a second preset frequency f2;

[0016] When entering the fresh air slight temperature rise dehumidification mode, the compressor is controlled to operate at a third preset frequency f3 which is higher than f2.

[0017] In some embodiments, when entering the fresh air slight cooling and dehumidification mode, the outdoor fan is controlled to run at a first preset speed n1;

[0018] When entering the fresh air non-cooling dehumidification mode, the outdoor fan is controlled to run at a second preset speed n2 which is lower than n1;

[0019] When entering the fresh air slight heating and dehumidification mode, the outdoor fan is controlled to run at a third preset speed n3 which is lower than n2.

[0020] In another aspect of the present application, the air conditioner comprises: a refrigerant circuit in which a compressor, an outdoor heat exchanger, a first electronic expansion valve, a first indoor heat exchanger, a second electronic expansion valve and a second indoor heat exchanger are connected in series; a fresh air module, wherein a fresh air outlet of the fresh air module can be connected to an indoor return air outlet of the air conditioner so that the fresh air introduced by the fresh air module flows to the indoor return air outlet; when the air conditioner is in operation, the fresh air flows from the indoor return air outlet first through the second indoor heat exchanger and then through the first indoor heat exchanger;

[0021] The control method of the air conditioner includes: a dehumidification step of controlling the opening of the second electronic expansion valve to adjust the cooling temperature of the second indoor heat exchanger so that the fresh air is cooled and dehumidified when flowing through the second indoor heat exchanger, and a fine temperature adjustment step of controlling the opening of the first electronic expansion valve or the frequency of the compressor according to the difference between the indoor return air temperature and the indoor target temperature or according to the difference between the indoor return air temperature and the outdoor ambient temperature so as to adjust the heating temperature of the first indoor heat exchanger so that the cooled fresh air is heated when flowing through the first indoor heat exchanger;

[0022] The dehumidification step specifically includes:

[0023] S11, based on indoor return air temperature T n and indoor return air relative humidity φ n Calculate the return air dew point temperature T L ;

[0024] Determine the coil temperature T of the second indoor heat exchanger P The interval to which T belongs: P ≤0℃, increase the opening of the second electronic expansion valve; if T P ≥T L , then reduce the opening of the second electronic expansion valve; if 0℃<T P <T L , then enter S12;

[0025] S12. Determine the relative humidity of indoor return air φ n and target relative humidity φ s The interval of the difference belongs to: if φ n -φ s < the first preset humidity difference threshold, then increase the opening of the second electronic expansion valve; if φ n -φ s > the second preset humidity difference threshold, then reduce the opening of the second electronic expansion valve; if the first preset humidity difference threshold ≤φ n -φ s ≤ the second preset humidity difference threshold, the opening of the second electronic expansion valve is kept unchanged.

[0026] In some embodiments, during the dehumidification step, when 0°C < T P <T LAnd the first preset humidity difference threshold ≤φ n -φ s ≤ the second preset humidity difference threshold, enter the fine temperature adjustment step.

[0027] In some embodiments, in S11, after the opening of the second electronic expansion valve increases or decreases, T is re-determined every first preset time Δt1. P The interval to which ?

[0028] In S12, after the opening degree of the second electronic expansion valve increases or decreases, the system returns to S11 and re-determines T at every first preset time Δt1. P The interval to which ?

[0029] In the fine temperature adjustment step, after the compressor frequency is increased or decreased, the interval to which the difference belongs is determined once every second preset time Δt2.

[0030] In some embodiments, in S11, the opening increment of the second electronic expansion valve is a first preset opening increment Δa. 21 ;

[0031] In S12, the opening increment of the second electronic expansion valve is smaller than the first preset opening increment Δa. 21 The second preset opening increment Δa 22 .

[0032] In some embodiments, in S11, the opening increment of the second electronic expansion valve is a first preset opening increment Δa. 21 ;

[0033] In S11, the opening degree of the second electronic expansion valve is reduced by a value less than the first preset opening degree increment Δa. 21 The first preset opening degree is reduced by Δa 23 .

[0034] In some embodiments, in S12, the opening degree reduction of the second electronic expansion valve is not greater than the first preset opening degree reduction Δa 23 The second preset opening degree is reduced by Δa 24 . BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of an indoor unit of an air conditioner according to some embodiments is shown;

[0036] Figure 2 A schematic diagram of a fresh air module of an air conditioner according to some embodiments is shown;

[0037] Figure 3 A schematic diagram showing a refrigerant circuit of an air conditioner according to some embodiments is shown;

[0038] Figure 4 A flow chart showing a dehumidification mode of an air conditioner according to some embodiments;

[0039] Figure 5 A flow chart showing a fresh air micro-cooling and dehumidification mode of an air conditioner according to some embodiments is shown;

[0040] Figure 6 A flow chart showing a fresh air non-cooling dehumidification mode of an air conditioner according to some embodiments;

[0041] Figure 7 A flow chart showing a fresh air slight temperature rise dehumidification mode of an air conditioner according to some embodiments is shown;

[0042] In the above figures, 1. compressor; 2. four-way valve; 3. outdoor heat exchanger; 4. first electronic expansion valve; 5. first indoor heat exchanger; 6. second electronic expansion valve; 7. second indoor heat exchanger; 10. shell; 11. indoor return air outlet; 12. air supply outlet; 20. indoor heat exchanger; 30. indoor fan; 40. fresh air module; 41. fresh air mold shell; 411. fresh air inlet; 412. fresh air outlet; 413. air guide; 42. fresh air fan. DETAILED DESCRIPTION

[0043] In order to make the purpose and implementation method of the present application clearer, the exemplary implementation method of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0044] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0045] The terms "first", "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0046] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0047] The implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0048] The air conditioner in this application performs a refrigeration cycle of the air conditioner by using a compressor, a condenser, an expansion valve and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion and evaporation, and supplies refrigeration capacity to the air that has been conditioned and heat exchanged.

[0049] The compressor compresses the refrigerant gas in a low temperature and low pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0050] The expansion valve expands the high-temperature and high-pressure liquid refrigerant condensed in the condenser into a low-pressure gas-liquid two-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a cooling effect by utilizing the latent heat of evaporation of the refrigerant to exchange heat with the material to be cooled. In the entire cycle, the air conditioner can adjust the temperature of the indoor space.

[0051] The outdoor unit of the air conditioner refers to a portion of a refrigeration cycle including a compressor and an outdoor heat exchanger, the indoor unit of the air conditioner includes an indoor heat exchanger, and an expansion valve may be provided in the indoor unit or the outdoor unit.

[0052] The indoor heat exchanger and the outdoor heat exchanger function as a condenser or an evaporator. When the indoor heat exchanger functions as a condenser, the air conditioner functions as a heater in a heating mode, and when the indoor heat exchanger functions as an evaporator, the air conditioner functions as a cooler in a cooling mode.

[0053] Reference Figure 1 The indoor unit of the air conditioner according to the embodiment of the present application includes a housing 10 having an indoor return air port 11 and an air supply port 12, an indoor heat exchanger 20 for performing heat exchange with air introduced into the housing 10, and an indoor fan 30 for circulating air. The indoor unit of the air conditioner of the present application may be a wall-mounted air conditioner installed on a wall.

[0054] The indoor fan 30 is used to force air to flow. Under the action of the indoor fan 30, air can enter the housing 10 from the indoor return air port 11, then flow through the indoor heat exchanger 20, and finally circulate into the room from the air supply port 12.

[0055] Combination Figure 2 The indoor unit of the air conditioner of the present application further comprises a fresh air module 40 for introducing outdoor fresh air into the room. The fresh air module 40 comprises a fresh air mold shell 41 having a fresh air inlet 411 and a fresh air outlet 412, and a fresh air fan 42 for introducing outdoor fresh air.

[0056] The fresh air inlet 411 is connected to the outdoors through a fresh air duct, and an air guide portion 413 is provided at the fresh air outlet 412 . The air guide portion 413 is used to guide the fresh air toward the indoor return air outlet 11 , so that the fresh air can flow from the fresh air outlet 412 to the indoor return air outlet 11 .

[0057] Specifically, the air guide 413 is arc-shaped, connected to the side wall of the fresh air outlet 412 away from the indoor return air outlet 11, and the arc-shaped opening of the air guide 413 faces the indoor return air outlet 11, so that the fresh air flowing out of the fresh air outlet 412 flows to the indoor return air outlet 11 under the guidance of the air guide 413. Figure 1 The middle arrow indicates the flow direction of fresh air. When the air conditioner introduces fresh air, the fresh air and indoor return air are mixed inside the indoor return air outlet 11, flow through the indoor heat exchanger 20 together, and flow to the air supply outlet 12, so that the temperature and humidity of the fresh air are processed through the indoor heat exchanger 20.

[0058] In the present application, the indoor heat exchanger 20 includes a first indoor heat exchanger 5 and a second indoor heat exchanger 7. On the air movement path from the indoor return air port 11 to the air supply port 12, the second indoor heat exchanger 7 is closer to the indoor return air port 11 than the first indoor heat exchanger 5, so that the air will flow through the second indoor heat exchanger 7 first and then through the first indoor heat exchanger 5.

[0059] In this application, reference is made to Figure 3 The refrigerant circuit of the air conditioner includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a first electronic expansion valve 4, a first indoor heat exchanger 5, a second electronic expansion valve 6 and a second indoor heat exchanger 7 which are connected in series to form a circuit.

[0060] During the refrigeration and dehumidification operation, in the refrigerant circuit, the refrigerant flows through the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the first electronic expansion valve 4, the first indoor heat exchanger 5, the second electronic expansion valve 6, the second indoor heat exchanger 7 in sequence, and then returns to the compressor 1 for circulation. The refrigerant releases heat in the outdoor heat exchanger 3, changes from superheated gas to two-phase flow, further releases heat in the first indoor heat exchanger 5, and absorbs heat in the second indoor heat exchanger 7, changes from two-phase flow to superheated gas; the air flows through the second indoor heat exchanger 7 and the first indoor heat exchanger 5 in sequence. After flowing through the second indoor heat exchanger 7, the temperature is greatly reduced, and a large amount of condensed water is precipitated, realizing the dehumidification of the air. After flowing through the first indoor heat exchanger 5, the temperature of the air is raised to a suitable temperature and then sent to the room, realizing the adjustment of the fresh air supply temperature.

[0061] The air conditioner of the present application can realize multiple dehumidification modes for fresh air / mixed air to meet different user requirements for comfort, including fresh air slight cooling dehumidification mode, fresh air non-cooling dehumidification mode and fresh air slight heating dehumidification mode.

[0062] For example, when the outdoor humidity is relatively high, the user needs the air conditioner to be able to dehumidify when using the air conditioner to introduce fresh air. In addition, if the outdoor temperature is slightly high, the user expects to lower the fresh air temperature when introducing fresh air. In this case, the slightly cooling dehumidification mode can be selected. If the outdoor temperature is relatively suitable, the user can choose the non-cooling dehumidification mode when he does not want to change the fresh air temperature. If the outdoor temperature is slightly low, the user expects to increase the fresh air temperature when introducing fresh air. In this case, the slightly heating dehumidification mode can be selected. The setting of multiple dehumidification modes provides users with a variety of options to meet users' different needs for fresh air temperature and humidity.

[0063] The following introduces the control methods of the air conditioner in various dehumidification modes.

[0064] The air conditioner of the present application also includes a return air temperature and humidity sensor, an outdoor temperature sensor and a second coil temperature sensor.

[0065] The return air temperature and humidity sensor can be installed at the indoor return air outlet 11 to detect the temperature Tn and relative humidity φ of the indoor return air. n The outdoor temperature sensor can be arranged on the outdoor unit of the air conditioner, or at the fresh air inlet 411 of the fresh air module 40, to detect the temperature T of the outdoor air. w The second coil temperature sensor can be arranged on the coil of the second indoor heat exchanger 7 to detect the coil temperature T p .

[0066] In the fresh air micro-cooling and dehumidification mode, both the first electronic expansion valve 4 and the second electronic expansion valve 5 are in a throttling state. The opening of the second electronic expansion valve 5 is relatively small, which can make the temperature at the second indoor heat exchanger 7 lower, which is conducive to cooling and dehumidifying the fresh air through the cooling effect of the second indoor heat exchanger 7; the opening of the first electronic expansion valve 4 is relatively large, which makes the temperature at the first indoor heat exchanger 5 higher, which is conducive to heating the fresh air through the heating effect of the first indoor heat exchanger 5. At the same time, due to the throttling effect of the first electronic expansion valve 4, the temperature at the first indoor heat exchanger 5 is lower than the temperature of the outdoor heat exchanger 3. After the fresh air temperature rises, it will still be lower than its initial temperature, realizing micro-cooling and dehumidification of the fresh air.

[0067] Fresh air initial temperature T w , the temperature is greatly reduced and dehumidified when passing through the second indoor heat exchanger 7, and the temperature drops to T w1 , and then the temperature rises to T after passing through the first indoor heat exchanger 5 w2 , then T w2 Slightly smaller than T w .

[0068] Understandably, T w A fluctuation range is allowed, rather than a fixed value.

[0069] In the fresh air non-cooling dehumidification mode and the fresh air slightly-heating mode, the first electronic expansion valve 4 is fully opened and the second electronic expansion valve 5 is in a throttling state. The second electronic expansion valve 5 has a smaller opening, which can make the temperature at the second indoor heat exchanger 7 lower, which is conducive to cooling and dehumidifying the fresh air through the cooling effect of the second indoor heat exchanger 7; the first electronic expansion valve 4 does not throttle, so that the temperature of the first indoor heat exchanger 5 is basically the same as that of the outdoor heat exchanger 3, which is conducive to heating the fresh air through the heating effect of the first indoor heat exchanger 5, so that the temperature of the fresh air returns to the initial temperature or slightly higher than the initial temperature, and realizes the dehumidification without cooling or slightly-heating dehumidification of the fresh air.

[0070] The condensing pressure in the fresh air slightly warming mode is slightly higher than that in the fresh air non-cooling dehumidification mode to achieve slight warming of the fresh air.

[0071] <Fresh air cooling and dehumidification>

[0072] After starting the fresh air micro-cooling and dehumidification mode, the fresh air fan and the indoor fan operate at the wind speed set by the user. The outdoor fan operates at the first preset speed n1, the compressor operates at the first preset frequency f1, and the initial opening of the first electronic expansion valve is a 11 , the initial opening of the second electronic expansion valve is a 21 .

[0073] The air conditioner receives the indoor target temperature T set by the user s and indoor target humidity φ s.

[0074] The indoor return air temperature T can be obtained by the return air temperature and humidity sensor n and indoor relative humidity φ n The second coil temperature sensor can obtain the coil temperature T of the second indoor heat exchanger p .

[0075] In the fresh air micro-cooling and dehumidification mode, the temperature and humidity of the indoor return air T n ,φ n and the coil temperature T of the second indoor heat exchanger p Adjust the opening of the second electronic expansion valve to adjust the cooling temperature of the second indoor heat exchanger, so that the fresh air is cooled and dehumidified when flowing through the second indoor heat exchanger, and adjust the indoor return air temperature T n and indoor target temperature T s The opening of the first electronic expansion valve is adjusted to adjust the heating temperature of the first indoor heat exchanger so that the fresh air after cooling and dehumidification is heated to the target temperature when flowing through the first indoor heat exchanger.

[0076] The dehumidification steps specifically include: S11, according to the indoor return air temperature T n and indoor return air relative humidity φ n Calculate the return air dew point temperature T L ; Determine the coil temperature T of the second indoor heat exchanger P In the interval: If T P ≤0℃, increase the opening of the second electronic expansion valve; if T P ≥T L , then reduce the opening of the second electronic expansion valve; if 0℃<T P <T L , then proceed to step S12;

[0077] Due to the indoor return air temperature T n and indoor return air relative humidity φ n Calculate the dew point temperature T L This belongs to the prior art, and its calculation process will not be described in detail here.

[0078] If the coil temperature of the second indoor heat exchanger is T P ≤0℃, indicating that the coil temperature of the second indoor heat exchanger is too low and there is a risk of frost. Therefore, it is necessary to increase the opening of the second electronic expansion valve, and the opening increment is the first preset opening increment Δa. 21 .

[0079] If the coil temperature of the second indoor heat exchanger is T P ≥Dew point temperature T L, indicating that the temperature of the second indoor heat exchanger coil is too high and the dehumidification effect is not good. Therefore, the opening of the second electronic expansion valve needs to be reduced by the first preset opening reduction Δa 23 If the coil temperature of the second indoor heat exchanger is T P Satisfy 0℃<T P <T L , indicating that at this temperature, the second indoor heat exchanger can dehumidify the fresh air and the heat exchanger will not frost, then entering step S12.

[0080] S12. Determine the relative humidity of indoor return air φ n and indoor target relative humidity φ s The difference between the interval: if φ n -φ s < the first preset humidity difference threshold, then increase the opening of the second electronic expansion valve; if φ n -φ s > the second preset humidity difference threshold, then reduce the opening of the second electronic expansion valve; if the first preset humidity difference threshold ≤φ n -φ s ≤ the second preset humidity difference threshold, the opening of the second electronic expansion valve is kept unchanged.

[0081] In this step, if φ n -φ s < the first preset humidity difference threshold, indicating that the dehumidification capacity is too much and the coil temperature of the second indoor heat exchanger is too low, which will make the fresh air too dry. Therefore, it is necessary to increase the opening of the second electronic expansion valve, and the opening increment is Δa 22 .

[0082] As the opening of the second electronic expansion valve increases, the coil temperature of the second indoor heat exchanger will rise, reducing the dehumidification capacity of the fresh air.

[0083] If φ n -φ s > the second preset humidity difference threshold, it means that the dehumidification capacity is too small and the coil temperature of the second indoor heat exchanger is too high. Therefore, the opening of the second electronic expansion valve needs to be reduced by Δa. 24 .

[0084] The opening degree of the second electronic expansion valve decreases, and the coil temperature of the second indoor heat exchanger decreases, thereby increasing the dehumidification capacity of the fresh air.

[0085] In steps S11 and S12, each time the opening of the second electronic expansion valve is adjusted, it is necessary to return to step S11 after an interval of Δt1 to re-judge T P In the interval, the opening degree of the second electronic expansion valve does not need to be changed.

[0086] In this application, the temperature of the second indoor heat exchanger coil is determined based on whether the temperature of the second indoor heat exchanger coil is between 0°C and the return air dew point temperature T L By adjusting the opening of the second electronic expansion valve, the temperature of the second indoor heat exchanger can have dehumidification capacity without frost; by adjusting the relative humidity difference of the return air (φ n -φ s ) is within the preset return air relative humidity difference range to further adjust the opening of the second electronic expansion valve, so that the temperature of the second indoor heat exchanger can be moderate for the dehumidification of the fresh air.

[0087] In the above dehumidification step, set Δa 23 ≥Δa 24 , the coil temperature T of the second indoor heat exchanger can be adjusted during the adjustment process. P Drop to the return air dew point temperature T L The following speed is faster, T P Drop to the return air dew point temperature T as quickly as possible L In the following, the second indoor heat exchanger can dehumidify the fresh air as quickly as possible, and the temperature drops slowly when the second indoor heat exchanger increases the dehumidification capacity, which can avoid excessive temperature drop and excessive dehumidification capacity.

[0088] Δa 21 >Δa 22 , Δa 21 >Δa 23 , the coil temperature T of the second indoor heat exchanger can be adjusted during the adjustment process. p The temperature rises to above 0°C the fastest, which can avoid frost on the second indoor heat exchanger as soon as possible.

[0089] When the second electronic expansion valve does not need to be changed in the dehumidification step, that is, 0℃<T P <T L And the first preset humidity difference threshold ≤φ n -φ s ≤ the second preset humidity difference threshold, enter the fine temperature adjustment step.

[0090] In the fresh air micro-cooling and dehumidification mode, the micro-temperature adjustment steps include: determining the indoor return air temperature T n and indoor target temperature T s The difference interval: if T n -T s < the first preset temperature difference threshold, then increase the opening of the first electronic expansion valve; if T n -T s > the second preset temperature difference threshold, then reduce the opening of the first electronic expansion valve; if the first preset temperature difference threshold ≤ T n -T s ≤ the second preset temperature difference threshold, the opening of the first electronic expansion valve is kept unchanged.

[0091] If T n -T s < the first preset temperature difference threshold, indicating that the supply air temperature and the return air temperature are low, and the coil temperature of the first indoor heat exchanger is low, so the opening of the first electronic expansion valve needs to be increased, and the opening increment is the preset value Δa 11 ;

[0092] Increasing the opening of the first electronic expansion valve can increase the temperature of the first indoor heat exchanger, thereby increasing the temperature of the fresh air.

[0093] If T n -T s > The second preset temperature difference threshold indicates that the supply air temperature and the return air temperature are too high, and the coil temperature of the second indoor heat exchanger is too high. Therefore, the opening of the first electronic expansion valve needs to be reduced by the preset value Δa. 12 ;

[0094] Reducing the opening of the first electronic expansion valve can reduce the temperature of the first indoor heat exchanger, thereby reducing the temperature of the fresh air.

[0095] If the first preset temperature difference threshold ≤T n -T s ≤ the second preset temperature difference threshold, indicating that the return air temperature is basically the same as the user-set temperature, the coil temperature of the first indoor heat exchanger is moderate, and the opening of the first electronic expansion valve does not need to be changed.

[0096] In the above T n -T s In the judgment of the interval, each time the opening of the first electronic expansion valve is adjusted, T is re-judged at an interval of Δt2. n -T s The interval is until the first preset temperature difference threshold ≤T n -T s ≤the second preset temperature difference threshold, the opening degree of the first electronic expansion valve remains unchanged.

[0097] In the embodiment of the present application, after the opening of the first electronic expansion valve is adjusted in the fine temperature adjustment step, the first preset temperature difference threshold ≤ T n -T s ≤ the second preset temperature difference threshold, and enter the next round of humidity adjustment step according to the real-time detection data of the sensor. This control process continues to run after the fresh air micro-cooling and dehumidification mode is started until the user turns off the fresh air micro-cooling and dehumidification mode.

[0098] In the present application, the opening of the first electronic expansion valve is controlled by judging whether the difference between the indoor return air temperature and the indoor target temperature is within a preset return air temperature difference range, so that the temperature of the first indoor heat exchanger is maintained within a suitable temperature range, thereby reaching the user-set temperature.

[0099] <Fresh air non-cooling dehumidification mode>

[0100] After starting the fresh air non-cooling dehumidification mode, the fresh air fan and the indoor fan operate at the wind speed set by the user. The outdoor fan operates at the second preset speed n2, the compressor operates at the second preset frequency f2, the first electronic expansion valve is fully opened, and the initial opening of the second electronic expansion valve is a 22 .

[0101] The air conditioner receives the indoor target humidity φ set by the user s .

[0102] The indoor return air temperature T can be obtained by the return air temperature and humidity sensor n and indoor relative humidity φ n ; The outdoor ambient temperature T is obtained by the outdoor temperature sensor w The second coil temperature sensor can obtain the coil temperature T of the second indoor heat exchanger p .

[0103] In the fresh air non-cooling dehumidification mode, the temperature and humidity of the indoor return air T n ,φ n and the coil temperature T of the second indoor heat exchanger p The opening of the second electronic expansion valve is adjusted to adjust the cooling temperature of the second indoor heat exchanger, so that the fresh air is cooled and dehumidified when flowing through the second indoor heat exchanger, and the return air temperature T is adjusted according to the dehumidification step. n and outdoor ambient temperature T w The frequency of the compressor is adjusted to adjust the heating temperature of the first indoor heat exchanger so that the fresh air after cooling and dehumidification is heated to the outdoor ambient temperature when flowing through the first indoor heat exchanger.

[0104] Since the control methods of the fresh air non-cooling dehumidification mode and the fresh air slightly cooling dehumidification mode differ only in the fine-tuning temperature step, only the fine-tuning temperature step is described in detail here. The dehumidification step can refer to the content in the fresh air slightly cooling dehumidification mode.

[0105] The steps of fine-tuning the temperature in the fresh air non-cooling dehumidification mode specifically include: determining the indoor return air temperature T n and outdoor ambient temperature T w The interval of the difference: if T n -T w < the first preset temperature difference threshold, then increase the frequency of the compressor; if T n -T w > the second preset temperature difference threshold, then reduce the frequency of the compressor; if the first preset temperature difference threshold ≤ T n -T w ≤ the second preset temperature difference threshold; the frequency of the compressor remains unchanged.

[0106] In this step, if T n -T w < the first preset temperature difference threshold, indicating that the return air temperature is low and the temperature of the first indoor heat exchanger coil is low, so the compressor frequency needs to be increased, and the frequency increment is Δf1; the increase in the compressor frequency can increase the temperature of the first indoor heat exchanger, thereby increasing the supply air temperature.

[0107] If T n -T w >The second preset temperature difference threshold value indicates that the return air temperature is too high and the temperature of the first indoor heat exchanger coil is too high, so the compressor frequency needs to be reduced by Δf2; the reduction in the compressor frequency can reduce the temperature of the first indoor heat exchanger, thereby reducing the supply air temperature.

[0108] If the first preset temperature difference threshold ≤T n -T w ≤ the second preset temperature difference threshold, indicating that the return air temperature is basically the same as the outdoor air temperature, the temperature of the first indoor heat exchanger coil is moderate, and the compressor frequency does not need to be changed.

[0109] In the above T n -T w In the judgment of the interval, each time the compressor frequency is adjusted, T is re-judged after an interval of Δt2. n -T w The interval is until the first preset temperature difference threshold ≤T n -T w ≤ the second preset temperature difference threshold, the compressor frequency remains unchanged.

[0110] In an embodiment of the present application, after the compressor frequency is adjusted in the fine-tuning step, the next round of dehumidification step is entered according to the data detected in real time by the sensor. The control process continues to run after the fresh air dehumidification mode without cooling is started until the user turns off the fresh air dehumidification mode without cooling.

[0111] In this application, by judging the indoor return air temperature T n and outdoor ambient temperature T w The compressor frequency is controlled by whether the temperature difference is within the preset return air temperature difference range, so that the temperature of the first indoor heat exchanger coil is maintained in an appropriate temperature range, and the return air temperature is basically consistent with the outdoor air temperature, thereby achieving the purpose of dehumidification without cooling the fresh air.

[0112] <Fresh air slight heating and dehumidification mode>

[0113] After starting the fresh air slight heating and dehumidification mode, the fresh air fan and the indoor fan operate at the wind speed set by the user. The outdoor fan operates at the third preset speed n3, the compressor operates at the third preset frequency f3, the first electronic expansion valve is fully opened, and the initial opening of the second electronic expansion valve is a 23 .

[0114] The air conditioner receives the indoor target temperature T set by the user s and indoor target humidity φ s .

[0115] The indoor return air temperature T can be obtained by the return air temperature and humidity sensor n and indoor relative humidity φ n The second coil temperature sensor can obtain the coil temperature T of the second indoor heat exchanger p .

[0116] In the fresh air slight temperature drop and dehumidification mode, the indoor return air temperature and humidity T n ,φ n and the coil temperature T of the second indoor heat exchanger p The opening of the second electronic expansion valve is adjusted to adjust the cooling temperature of the second indoor heat exchanger, so that the fresh air is cooled and dehumidified when flowing through the second indoor heat exchanger, and the return air temperature T is adjusted according to the dehumidification step. n and indoor target temperature T s The frequency of the compressor is adjusted to adjust the heating temperature of the first indoor heat exchanger so that the fresh air after cooling and dehumidification is heated to the target temperature when flowing through the first indoor heat exchanger.

[0117] Since the control methods of the fresh air micro-heating dehumidification mode and the fresh air micro-cooling dehumidification mode differ only in the fine-temperature adjustment step, only the fine-temperature adjustment step is described in detail here. The dehumidification step can refer to the content in the fresh air micro-cooling dehumidification mode.

[0118] The fine-tuning steps in the fresh air micro-heating dehumidification mode specifically include: determining the indoor return air temperature T n and indoor target temperature T s The difference interval: if T n -T s < the first preset temperature difference threshold, then increase the frequency of the compressor; if T n -T s > the second preset temperature difference threshold, then reduce the frequency of the compressor; if the first preset temperature difference threshold ≤ T n -T s ≤ the second preset temperature difference threshold, the frequency of the compressor is kept unchanged.

[0119] In this step, T n -T s< the first preset temperature difference threshold, indicating that the return air temperature is low and the temperature of the first indoor heat exchanger coil is low, so the compressor frequency needs to be increased, and the frequency increment is Δf1; the increase in the compressor frequency can increase the temperature of the first indoor heat exchanger, thereby increasing the supply air temperature.

[0120] If T n -T s >The second preset temperature difference threshold value indicates that the return air temperature is too high and the temperature of the first indoor heat exchanger coil is too high, so the compressor frequency needs to be reduced by Δf2; the reduction in the compressor frequency can reduce the temperature of the first indoor heat exchanger, thereby reducing the supply air temperature.

[0121] If the first preset temperature difference threshold ≤T n -T s ≤ the second preset temperature difference threshold, indicating that the return air temperature is basically the same as the user-set temperature, the temperature of the first indoor heat exchanger coil is moderate, and the compressor frequency does not need to be changed.

[0122] In the above T n -T s In the judgment of the interval, each time the compressor frequency is adjusted, T is re-judged after an interval of Δt2. n -T s The interval is until the first preset temperature difference threshold ≤T n -T s ≤ the second preset temperature difference threshold, the compressor frequency remains unchanged.

[0123] In an embodiment of the present application, after the compressor frequency is adjusted in the fine-tuning step, the next round of dehumidification step is entered according to the real-time detection data of the sensor. The control process continues to run after the fresh air micro-heating dehumidification mode is started until the user turns off the fresh air micro-heating dehumidification mode.

[0124] In this application, by judging the indoor return air temperature T n and indoor target temperature T s The compressor frequency is controlled based on whether the difference is within the preset temperature difference range, so that the temperature of the first indoor heat exchanger coil is maintained within the appropriate temperature range, and the return air temperature is basically consistent with the user-set temperature, thereby achieving the purpose of fresh air slight heating and dehumidification.

[0125] In some embodiments of the present application, the relationship between the second preset frequency f2 of the compressor in the fresh air non-cooling dehumidification mode and the third preset frequency f3 of the compressor in the fresh air slightly-heating dehumidification mode satisfies f2<f3. Since the fresh air needs to be slightly heated in the fresh air slightly-heating dehumidification mode, the required condensation pressure is relatively large, so f3 is set relatively large, so that the temperature of the fresh air can meet the air supply demand as soon as possible in the fresh air slightly-heating dehumidification mode, avoiding the problem that the compressor has a low frequency at the beginning and needs to adjust the frequency multiple times to meet the condensation demand; f2 is set relatively small to avoid energy waste.

[0126] In some embodiments of the present application, the initial opening degree a of the second electronic expansion valve in the fresh air slight cooling and dehumidification mode is 21 , the initial opening degree of the second electronic expansion valve in the fresh air non-cooling dehumidification mode a 22 , the initial opening degree of the second electronic expansion valve in the fresh air slight temperature rise dehumidification mode a 23 The relationship between them satisfies: a 21 >a 22 >a 23 . As the required condensing temperature gradually increases and the high and low pressure difference gradually increases from fresh air slightly cooling dehumidification → fresh air non-cooling dehumidification → fresh air slightly heating dehumidification, the required opening of the second electronic expansion valve gradually decreases, and a is set. 21 >a 22 >a 23 The number of times the second electronic expansion valve is adjusted in the dehumidification step can be reduced, the opening of the second electronic expansion valve can be adjusted quickly, and the working efficiency of the system is improved.

[0127] In some embodiments of the present application, the relationship between the first preset speed n1 of the outdoor fan in the fresh air slight cooling dehumidification mode, the second preset speed n2 of the outdoor fan in the fresh air non-cooling dehumidification mode, and the third preset speed n3 of the outdoor fan in the fresh air slight heating dehumidification mode satisfies: n1>n2>n3. Since the required outdoor unit heat exchange amount gradually decreases from fresh air slight cooling dehumidification → fresh air non-cooling dehumidification → fresh air slight heating dehumidification, the speed of the outdoor fan is set to decrease accordingly, which can avoid energy waste.

[0128] The first concept of the present application is that the fresh air module can supply air to the indoor return air outlet, so that the fresh air can enter the heat exchange duct of the air conditioner. At the same time, a first indoor heat exchanger and a second indoor heat exchanger are set up, so that the fresh air can reach a suitable supply air temperature while dehumidifying.

[0129] The second concept of the present application is that the air conditioner realizes multiple dehumidification modes for fresh air, which can meet the different needs of users for comfort and improve the user experience.

[0130] The third concept of the present application is to adjust the opening of the second electronic expansion valve according to whether the temperature of the second indoor heat exchanger coil is between 0°C and the return air dew point temperature TL, so that the temperature of the second indoor heat exchanger is within the fresh air dehumidification temperature range without frost; according to the return air relative humidity difference (φ n -φ s ) is within the preset return air relative humidity difference range to further adjust the opening of the second electronic expansion valve, so that the temperature of the second indoor heat exchanger can be moderate for the dehumidification of the fresh air.

[0131] The fourth concept of the present application is to control the opening of the first electronic expansion valve by judging whether the difference between the indoor return air temperature and the indoor target temperature is within a preset return air temperature difference range, so that the temperature of the first indoor heat exchanger can be maintained within a suitable temperature range, thereby reaching the user-set temperature and realizing fresh air micro-cooling and dehumidification.

[0132] The fifth concept of the present application is to determine the indoor return air temperature T n and outdoor ambient temperature T w The compressor frequency is controlled by whether the temperature difference is within the preset return air temperature difference range, so that the temperature of the first indoor heat exchanger coil is maintained in an appropriate temperature range, and the return air temperature is basically consistent with the outdoor air temperature, thereby achieving the purpose of dehumidification without cooling the fresh air.

[0133] The sixth concept of the present application is to determine the indoor return air temperature T n and indoor target temperature T s The compressor frequency is controlled based on whether the difference is within the preset temperature difference range, so that the temperature of the first indoor heat exchanger coil is maintained within the appropriate temperature range, and the return air temperature is basically consistent with the user-set temperature, thereby achieving the purpose of fresh air slight heating and dehumidification.

[0134] The seventh concept of the present application is to set Δa 23 ≥Δa 24 , the coil temperature T of the second indoor heat exchanger can be adjusted during the adjustment process. P Drop to the return air dew point temperature T L The following speed is faster, T p Drop to the return air dew point temperature T as quickly as possible L In the following, the second indoor heat exchanger can dehumidify the fresh air as quickly as possible, and the temperature drops slowly when the second indoor heat exchanger increases the dehumidification capacity, which can avoid excessive temperature drop and excessive dehumidification capacity.

[0135] The eighth concept of the present application is to set Δa 21 >Δa 22 , Δa 21 >Δa 23 , the coil temperature T of the second indoor heat exchanger can be adjusted during the adjustment process.p The temperature rises to above 0°C the fastest, which can avoid frost on the second indoor heat exchanger as soon as possible.

[0136] The ninth concept of the present application, since f2 is set to be less than f3, f3 is set to be relatively large, so that in the fresh air micro-heating dehumidification mode, the temperature of the fresh air can meet the air supply demand as soon as possible, avoiding the problem that the compressor has a low frequency at the beginning and needs to adjust the frequency multiple times to meet the heating demand; f2 is set to be relatively small to avoid energy waste.

[0137] The tenth concept of the present application is that due to the setting of a 21 >a 22 >a 23 , the number of times the second electronic expansion valve is adjusted in the dehumidification step can be reduced, the opening of the second electronic expansion valve can be adjusted quickly, and the working efficiency of the system is improved.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0139] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A method for controlling an air conditioner, characterized in that: The air conditioner comprises: A refrigerant circuit including a compressor, an outdoor heat exchanger, a first electronic expansion valve, a first indoor heat exchanger, a second electronic expansion valve and a second indoor heat exchanger connected in series in sequence; A fresh air module, wherein the fresh air outlet of the fresh air module can be connected to the indoor return air outlet of the air conditioner, so that the fresh air introduced by the fresh air module flows to the indoor return air outlet; When the air conditioner is in operation, fresh air flows from the indoor return air outlet first through the second indoor heat exchanger and then through the first indoor heat exchanger; The control method of the air conditioner includes: controlling the opening of the second electronic expansion valve according to the temperature of the second indoor heat exchanger and the relative humidity of the indoor return air to adjust the cooling temperature of the second indoor heat exchanger so that the fresh air is cooled and dehumidified when flowing through the second indoor heat exchanger; and controlling the opening of the first electronic expansion valve or the frequency of the compressor according to the difference between the indoor return air temperature and the indoor target temperature or according to the difference between the indoor return air temperature and the outdoor ambient temperature to adjust the heating temperature of the first indoor heat exchanger so that the cooled fresh air is heated when flowing through the first indoor heat exchanger.

2. The air conditioner control method according to claim 1, characterized in that: The air conditioner can operate at least one of the following fresh air slight cooling and dehumidification mode, fresh air non-cooling and dehumidification mode, and fresh air slight heating and dehumidification mode: In the fresh air micro-cooling and dehumidification mode, the micro-temperature adjustment step includes determining the difference between the indoor return air temperature and the indoor target temperature, and when the difference is less than the lower limit of the preset temperature difference range, increasing the opening of the first electronic expansion valve; When the difference is greater than the upper limit of the preset temperature difference range, reducing the opening of the first electronic expansion valve; In the fresh air non-cooling dehumidification mode, the fine temperature adjustment step includes controlling the first electronic expansion valve to be fully opened; judging the difference between the indoor return air temperature and the outdoor ambient temperature, and when the difference is less than the lower limit of the preset temperature difference interval, increasing the frequency of the compressor; when the difference is greater than the upper limit of the preset temperature difference interval, reducing the frequency of the compressor; In the fresh air micro-heating dehumidification mode, the fine temperature adjustment step includes controlling the first electronic expansion valve to be fully open; judging the difference between the indoor return air temperature and the indoor target temperature, and when the difference is less than the lower limit of the preset temperature difference range, increasing the frequency of the compressor; when the difference is greater than the upper limit of the preset temperature difference range, reducing the frequency of the compressor.

3. The air conditioner control method according to claim 2, characterized in that: When entering the fresh air slight cooling and dehumidification mode, the second electronic expansion valve opens at the initial opening degree a. 21 Open; When entering the fresh air non-cooling dehumidification mode, the second electronic expansion valve is lower than a 21 The initial opening a 22 Open; When entering the fresh air slight heating and dehumidification mode, the second electronic expansion valve is lower than a 22 The initial opening a 23 Turn on.

4. The air conditioner control method according to claim 2, characterized in that: When entering the fresh air non-cooling dehumidification mode, the compressor is controlled to operate at the second preset frequency f2; When entering the fresh air slight temperature rise dehumidification mode, the compressor is controlled to operate at a third preset frequency f3 which is higher than f2.

5. The air conditioner control method according to claim 2, characterized in that: When entering the fresh air slight cooling and dehumidification mode, the outdoor fan is controlled to run at the first preset speed n1; When entering the fresh air non-cooling dehumidification mode, the outdoor fan is controlled to run at a second preset speed n2 which is lower than n1; When entering the fresh air slight heating and dehumidification mode, the outdoor fan is controlled to run at a third preset speed n3 which is lower than n2.

6. A method for controlling an air conditioner, characterized in that: The air conditioner comprises: A refrigerant circuit including a compressor, an outdoor heat exchanger, a first electronic expansion valve, a first indoor heat exchanger, a second electronic expansion valve and a second indoor heat exchanger connected in series in sequence; A fresh air module, wherein the fresh air outlet of the fresh air module can be connected to the indoor return air outlet of the air conditioner, so that the fresh air introduced by the fresh air module flows to the indoor return air outlet; When the air conditioner is in operation, fresh air flows from the indoor return air outlet first through the second indoor heat exchanger and then through the first indoor heat exchanger; The control method of the air conditioner comprises: a dehumidification step of controlling the opening of the second electronic expansion valve to adjust the cooling temperature of the second indoor heat exchanger so that the fresh air is cooled and dehumidified when flowing through the second indoor heat exchanger, and a fine temperature adjustment step of controlling the opening of the first electronic expansion valve or the frequency of the compressor according to the difference between the indoor return air temperature and the indoor target temperature or according to the difference between the indoor return air temperature and the outdoor ambient temperature so as to adjust the heating temperature of the first indoor heat exchanger so that the cooled fresh air is heated when flowing through the first indoor heat exchanger; The dehumidification step specifically includes: S11, based on indoor return air temperature T n and indoor return air relative humidity φ n Calculate the return air dew point temperature T L ; Determine the coil temperature T of the second indoor heat exchanger P The interval to which T belongs: P ≤0℃, increase the opening of the second electronic expansion valve; if T P ≥T L , then reduce the opening of the second electronic expansion valve; if 0℃ <T P <T L , then enter S12; S12. Determine the relative humidity of indoor return air φ n and target relative humidity φ s The interval of the difference belongs to: if φ n -φ s <first preset humidity difference threshold, then increase the opening of the second electronic expansion valve; if φ n -φ s > the second preset humidity difference threshold, then reduce the opening of the second electronic expansion valve; if the first preset humidity difference threshold ≤φ n -φ s ≤ the second preset humidity difference threshold, the opening of the second electronic expansion valve is kept unchanged.

7. The air conditioner control method according to claim 6, characterized in that: The air conditioner can operate at least one of the following fresh air slight cooling and dehumidification mode, fresh air non-cooling and dehumidification mode, and fresh air slight heating and dehumidification mode: In the fresh air micro-cooling and dehumidification mode, the micro-temperature adjustment step includes determining the difference between the indoor return air temperature and the indoor target temperature, and when the difference is less than the lower limit of the preset temperature difference range, increasing the opening of the first electronic expansion valve; When the difference is greater than the upper limit of the preset temperature difference range, reducing the opening of the first electronic expansion valve; In the fresh air non-cooling dehumidification mode, the fine temperature adjustment step includes controlling the first electronic expansion valve to be fully opened; judging the difference between the indoor return air temperature and the outdoor ambient temperature, and when the difference is less than the lower limit of the preset temperature difference interval, increasing the frequency of the compressor; when the difference is greater than the upper limit of the preset temperature difference interval, reducing the frequency of the compressor; In the fresh air micro-heating dehumidification mode, the fine temperature adjustment step includes controlling the first electronic expansion valve to be fully open; judging the difference between the return air temperature and the indoor target temperature, and when the difference is less than the lower limit of the preset temperature difference range, increasing the frequency of the compressor; when the difference is greater than the upper limit of the preset temperature difference range, reducing the frequency of the compressor.

8. The air conditioner control method according to claim 6, characterized in that: In the dehumidification step, when 0℃ <T P <T L And the first preset humidity difference threshold ≤φ n -φ s ≤ the second preset humidity difference threshold, enter the fine temperature adjustment step.

9. The air conditioner control method according to claim 6, characterized in that: In S11, after each change in the opening degree of the second electronic expansion valve, the T is re-judged once at a first preset time interval Δt1. P The interval to which ? In S12, after each change in the opening degree of the second electronic expansion valve, the first preset time Δt1 is passed back to S11 to re-determine T P The interval to which .

10. The air conditioner control method according to claim 6, characterized in that: In S11, the opening increment of the second electronic expansion valve is a first preset opening increment Δa. 21 , the opening degree reduction of the second electronic expansion valve is less than the first preset opening degree increment Δa 21 The first preset opening degree is reduced by Δa 23 ; In S12, the opening increment of the second electronic expansion valve is smaller than the first preset opening increment Δa. 21 The second preset opening increment Δa 22 .

Images