Air conditioner and control method of air conditioner

Abstract

The application discloses an air conditioner and a control method thereof. The air conditioner comprises: a refrigeration system comprising a compressor and a pressure switch; the compressor is used for compressing refrigerant; the pressure switch is used for detecting a pressure value in the refrigeration system, and is switched to a first state when the detected pressure value is greater than a preset pressure threshold, and is switched to a second state when the detected pressure value is less than or equal to the preset pressure threshold; and a controller is used for, when the running time of the compressor is less than a first preset time length, reducing the running frequency of the compressor by a preset frequency value every time a preset high-pressure condition is met; wherein the preset high-pressure condition is that the pressure switch is switched from the second state to the first state and the holding time of the first state reaches a second preset time length. The embodiment of the application can effectively avoid system shutdown caused by pressure overshoot, thereby improving the high-temperature running capability of the air conditioner.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of household appliances, in particular to an air conditioner and a control method of the air conditioner. BACKGROUND

[0002] At present, a pressure switch is arranged in the refrigeration system of some air conditioners. When the refrigerant pressure in the system rises to the set pressure, the pressure switch is automatically turned on, so that the system cannot work normally. When the refrigerant pressure in the system falls to the set pressure, the pressure switch is automatically connected to make the system work normally. The present inventors find in the implementation of the present application that in high-temperature working conditions, the load of the outdoor unit of the air conditioner is large, and the outdoor unit is affected by the fluctuation of the outdoor environment and the voltage fluctuation. For the model with the pressure switch, high pressure overshoot occurs, causing the system to stop, so that the air conditioner cannot run in high ambient temperature. SUMMARY

[0003] The embodiments of the present application provide an air conditioner and a control method of the air conditioner, which can effectively avoid system shutdown caused by pressure overshoot, thereby improving the high-temperature running capability of the air conditioner.

[0004] An embodiment of the present application provides an air conditioner, comprising:

[0005] a refrigeration system comprising a compressor and a pressure switch; the compressor is used for compressing refrigerant; the pressure switch is used for detecting the pressure value in the refrigeration system, and is switched to a first state when the detected pressure value is greater than a preset pressure threshold, and is switched to a second state when the detected pressure value is less than or equal to the preset pressure threshold;

[0006] a controller configured to, when the start-up time length of the compressor is less than a first preset time length, control the operating frequency of the compressor to decrease by a preset frequency value each time a preset high-pressure condition is detected; wherein the preset high-pressure condition is that the pressure switch is switched from the second state to the first state and the holding time of the first state reaches a second preset time length.

[0007] Compared with the prior art, the air conditioner provided by the embodiment can continuously detect whether the preset high-pressure condition is met when the start-up time length of the compressor is less than the first preset time length, that is, in the initial start-up stage of the compressor, and control the operating frequency of the compressor to decrease by the preset frequency value each time the action time of the pressure switch switching to the first state meets the second preset time length. Thus, the refrigerant pressure can be reduced by reducing the frequency of the compressor, the system shutdown caused by pressure overshoot can be effectively avoided, and the high-temperature running capability of the air conditioner is improved.

[0008] As an improvement of the above-mentioned scheme, the air conditioner further comprises a temperature detection device configured to detect the outdoor environment temperature.

[0009] The controller is further configured to:

[0010] acquire a current outdoor ambient temperature when the compressor is started;

[0011] determine a target frequency of the compressor according to the current outdoor ambient temperature;

[0012] control the compressor to operate at the target frequency;

[0013] The controller is further configured to increase the high-pressure number by one when controlling the operating frequency of the compressor to decrease by the preset frequency value, and the initial value of the high-pressure number is zero.

[0014] The controller is further configured to control the compressor to suspend the frequency increasing operation until the preset high-pressure condition is not met when the high-pressure number is greater than one.

[0015] In this embodiment, the frequency increasing operation of the compressor is controlled according to the outdoor ambient temperature when the compressor is started, which can ensure that the refrigerating capacity matches the ambient temperature, thereby improving the high-temperature operating capacity of the air conditioner. In addition, if the preset high-pressure condition continues to be detected, the frequency increasing operation of the compressor is prohibited while the frequency of the compressor is decreased, thereby further avoiding pressure overshoot.

[0016] As an improvement of the above scheme, the controller is further configured to increase the high-pressure number by one when controlling the operating frequency of the compressor to decrease by the preset frequency value, and the initial value of the high-pressure number is zero.

[0017] The refrigerating system further comprises an electronic expansion valve for controlling the flow of refrigerant.

[0018] The controller is further configured to:

[0019] When the starting duration of the compressor is equal to or greater than the first preset duration, the size relationship between the high-pressure number and a preset number is determined.

[0020] If the high-pressure number is less than or equal to the preset number, the electronic expansion valve is controlled according to a preset valve control strategy, and the high-pressure number is cleared.

[0021] If the high-pressure number is greater than the preset number, the opening degree of the electronic expansion valve is increased by a first preset step, the electronic expansion valve is controlled according to the preset valve control strategy, and the high-pressure number is cleared.

[0022] In the embodiment, when the starting time of the air conditioner is equal to or greater than the first preset time, that is, in the normal operation stage of the compressor, if the number of times that the preset high pressure condition is not met is too large, the opening degree of the electronic expansion valve is further increased in the case of consistent frequency, the throttling of the system is reduced, and the pressure switch protection time is used as a control parameter to control the coupling of the compressor frequency and the opening degree of the electronic expansion valve, so that the system pressure is more accurately adjusted, and pressure overshoot is further avoided.

[0023] As an improvement of the above scheme, the valve control strategy comprises:

[0024] obtaining a target discharge temperature and a current discharge temperature of the electronic expansion valve;

[0025] controlling the electronic expansion valve according to a difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve.

[0026] In the embodiment, the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve can well reflect whether the refrigeration system meets the refrigeration demand, so that the electronic expansion valve is controlled according to the difference, the capacity of the refrigeration system is ensured, and pressure overshoot is avoided.

[0027] Further, the opening degree control of the electronic expansion valve according to the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve comprises:

[0028] when the difference is greater than a first preset difference and the duration reaches a third preset time, controlling the electronic expansion valve to close the valve at a first speed;

[0029] when the difference is greater than a second preset difference and the duration reaches a third preset time, controlling the electronic expansion valve to close the valve at a second speed; wherein the second preset difference is less than the first preset difference, and the second speed is less than the first speed;

[0030] when the difference is between the second preset difference and a third preset difference and the duration reaches a third preset time, controlling the electronic expansion valve to close the valve at a third speed; wherein the third preset difference is less than the second preset difference, and the third speed is less than the second speed.

[0031] In the embodiment, the greater the difference, the faster the closing speed of the valve is controlled, so that the time consumption to reach the target discharge temperature is shortened, and the capacity of the refrigeration system is improved. The smaller the difference, the closer to the target temperature, so as to avoid system pressure overshoot, reduce the speed, and avoid the closing of the valve too fast to cause system pressure overshoot.

[0032] As an improvement of the above scheme, the controller is further configured to:

[0033] In the case that the starting time length of the compressor is equal to or greater than the first preset time length, the opening degree of the electronic expansion valve is increased by a second preset step number each time the preset high pressure condition is detected to be met.

[0034] In this embodiment, the opening degree of the electronic expansion valve is increased if the preset high pressure condition is met, so as to reduce the throttling of the system, reduce the system pressure, and avoid pressure overshoot.

[0035] As an improvement of the above scheme, the controller is further configured to increase the high pressure number by one when the opening degree of the electronic expansion valve is increased by a second preset step number.

[0036] The controller is further configured to suspend the control of the electronic expansion valve according to the preset valve control strategy when the high pressure number is greater than one, until the preset high pressure condition is not met.

[0037] In this embodiment, if the preset high pressure condition is met multiple times during the normal operation stage of the compressor, the control of the electronic expansion valve according to the preset valve control strategy is suspended, so as to avoid the increase of the throttling of the system caused by valve closing, and to avoid the increase of the system pressure.

[0038] Correspondingly, another embodiment of the present application provides a control method of an air conditioner, wherein the refrigeration system of the air conditioner comprises a compressor and a pressure switch; the compressor is configured to compress refrigerant; the pressure switch is configured to detect the pressure value in the refrigeration system, and switch to a first state when the detected pressure value is greater than a preset pressure threshold value, and switch to a second state when the detected pressure value is less than or equal to the preset pressure threshold value; the method comprises:

[0039] In the case that the starting time length of the compressor is less than the first preset time length, the operating frequency of the compressor is reduced by a preset frequency value each time the preset high pressure condition is detected to be met; wherein the preset high pressure condition is that the pressure switch switches from the second state to the first state, and the holding time in the first state reaches the second preset time length.

[0040] Compared with the prior art, the control method of the air conditioner provided in this embodiment can detect whether the preset high pressure condition is met during the starting time length of the compressor, i.e., during the initial starting stage of the compressor, and reduce the operating frequency of the compressor by a preset frequency value each time the action time of the pressure switch switching to the first state meets the second preset time length, so as to reduce the refrigerant pressure by reducing the frequency of the compressor, effectively avoid the system shutdown caused by pressure overshoot, and improve the high temperature operation capability of the air conditioner.

[0041] As an improvement of the above scheme, the method further comprises:

[0042] increment the high pressure number by one while reducing the running frequency of the compressor by a preset frequency value; wherein an initial value of the high pressure number is zero;

[0043] The refrigeration system further comprises an electronic expansion valve for controlling refrigerant flow;

[0044] The method further comprises:

[0045] acquiring a current outdoor ambient temperature when the compressor is started;

[0046] determining a target opening degree of the electronic expansion valve according to the current outdoor ambient temperature;

[0047] controlling the electronic expansion valve to adjust to the target opening degree;

[0048] determining a size relationship between the high pressure number and a preset number when a starting duration of the compressor is equal to or greater than the first preset duration;

[0049] if the high pressure number is less than or equal to the preset number, controlling the electronic expansion valve according to a preset valve control strategy and clearing the high pressure number;

[0050] if the high pressure number is greater than the preset number, increasing the opening degree of the electronic expansion valve by a first preset step number, controlling the electronic expansion valve according to the preset valve control strategy, and clearing the high pressure number.

[0051] In this embodiment, when the starting duration of the air conditioner is equal to or greater than the first preset duration, that is, in the normal running phase of the compressor, if the preset high pressure condition is not met too many times, the opening degree of the electronic expansion valve is further increased under the condition that the frequency is consistent, the throttling of the system is reduced, and the protection time of the pressure switch is taken as a control parameter to couple the compressor frequency and the opening degree of the electronic expansion valve for control, so as to more accurately adjust the system pressure and further avoid pressure overshoot.

[0052] As an improvement of the above scheme, the valve control strategy comprises:

[0053] acquiring a target discharge temperature and a current discharge temperature of the electronic expansion valve;

[0054] controlling the electronic expansion valve according to a difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve.

[0055] In this embodiment, the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve can well reflect whether the refrigeration system meets the refrigeration demand, so that the electronic expansion valve is controlled according to the difference, the capacity of the refrigeration system can be ensured, and pressure overshoot can be avoided. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 is a schematic diagram of the overall structure of an air conditioner according to an embodiment of the present application;

[0057] Figure 2 is a schematic diagram of the circuit structure of an air conditioner according to an embodiment of the present application;

[0058] Figure 3 is a schematic diagram of the sectional structure of an indoor unit of an air conditioner according to an embodiment of the present application;

[0059] Figure 4 is a schematic diagram of the signal connection of an air conditioner according to an embodiment of the present application;

[0060] Figure 5 is a schematic diagram of the specific working process of an air conditioner according to an embodiment of the present application;

[0061] Figure 6 is a schematic diagram of the signal connection of an air conditioner according to another embodiment of the present application;

[0062] Figure 7 is a schematic diagram of the specific working process of an air conditioner according to another embodiment of the present application;

[0063] Figure 8 is a schematic diagram of the signal connection of an air conditioner according to another embodiment of the present application;

[0064] Figure 9 is a schematic diagram of the specific working process of an air conditioner according to another embodiment of the present application;

[0065] Figure 10 is a schematic diagram of the specific working process of an air conditioner according to another embodiment of the present application;

[0066] Figure 11 is a schematic diagram of the specific working process of an air conditioner according to another embodiment of the present application. DETAILED DESCRIPTION

[0067] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0068] In the description of the present application, it needs to be explained that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0069] In the description of the present application, it needs to be explained that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0070] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict between them.

[0071] Reference Figure 1 is a structural schematic diagram of an air conditioner provided by an embodiment of the present application.

[0072] The air conditioner 1 provided by the embodiment of the present application includes an outdoor unit 2 and an indoor unit 3. The outdoor unit 2 of the air conditioner 1 refers to the part of the refrigeration cycle including the compressor 11 and the outdoor heat exchanger, and the indoor unit 3 of the air conditioner 1 includes the indoor heat exchanger, and the electronic expansion valve 14 can be provided in the indoor unit 3 or the outdoor unit 2.

[0073] The outdoor unit 2 is usually arranged outdoors and is used for indoor environment heat exchange. In addition, in Figure 1 In the illustration, the outdoor unit 2 is located on the opposite side of the indoor unit 3 across the wall surface WL outdoors, and the outdoor unit 2 is represented by a dashed line.

[0074] Figure 2 The circuit structure of the air conditioner 1 is shown in the figure, which is provided with a refrigeration system 10, and by circulating the refrigerant in the refrigeration system 10, a vapor compression refrigeration cycle can be performed. The on-line pipe 4 is connected to the indoor unit 3 and the outdoor unit 2 to form the refrigeration system 10 for circulating the refrigerant. The refrigeration system 10 is provided with a compressor 11, an outdoor heat exchanger 13, an electronic expansion valve 14, a liquid accumulator 15, an indoor heat exchanger 16 and a pressure switch 12 (not shown in the figure).

[0075] The indoor heat exchanger 16 and the outdoor heat exchanger 13 operate as condensers or evaporators. The compressor 11 draws in refrigerant from the suction port and discharges the internally compressed refrigerant to the indoor heat exchanger 16 from the discharge port. The outdoor heat exchanger 13 has a first inlet and outlet for circulating the refrigerant between the accumulator 15 and the suction port of the compressor 11, and a second inlet and outlet for circulating the refrigerant between the accumulator 15 and the electronic expansion valve 14. The outdoor heat exchanger 13 exchanges heat between the refrigerant flowing in the heat transfer pipe (not shown) connected between the second inlet and outlet of the outdoor heat exchanger 13 and the first inlet and outlet and the outdoor air.

[0076] The electronic expansion valve 14 is positioned between the outdoor heat exchanger 13 and the indoor heat exchanger 16. It expands and reduces the pressure of the refrigerant flowing between the outdoor heat exchanger 13 and the indoor heat exchanger 16. The opening of the electronic expansion valve 14 is adjustable. Decreasing the opening increases the flow resistance of the refrigerant through the electronic expansion valve 14, while increasing the opening decreases the flow resistance. Furthermore, even if the conditions of other components installed in the refrigeration system 10 remain unchanged, changing the opening of the electronic expansion valve 14 changes the flow rate of the refrigerant flowing through the refrigeration system 10. The indoor heat exchanger 16 has a second inlet and outlet for communicating liquid refrigerant with the electronic expansion valve 14 and a first inlet and outlet for communicating gaseous refrigerant with the discharge port of the compressor 11. The indoor heat exchanger 16 exchanges heat between the refrigerant flowing in the heat transfer pipe connected between the second inlet and the first inlet of the indoor heat exchanger 16 and the indoor air. An accumulator 15 is disposed between the outdoor heat exchanger 13 and the suction port of the compressor 11. In the accumulator 15, the refrigerant flowing from the outdoor heat exchanger 13 to the compressor 11 is separated into gas refrigerant and liquid refrigerant. Furthermore, the gas refrigerant is primarily supplied from the accumulator 15 to the suction port of the compressor 11.

[0077] The outdoor unit 2 includes an outdoor fan 21 that generates an airflow of outdoor air through the outdoor heat exchanger 13 to promote heat exchange between the refrigerant flowing in the heat transfer tube and the outdoor air. The outdoor fan 21 is driven by an outdoor fan motor 21a that can change its rotation speed. Figure 2 and Figure 3 The indoor unit 3 includes a fan 31 that generates airflow of indoor air through the indoor heat exchanger 16 to promote heat exchange between the refrigerant flowing in the heat transfer tube and the indoor air. The fan 31 is driven by an indoor fan motor 31a that can change its speed. Figure 3As shown, the indoor unit 3 is provided with a housing 61, an air filter, and a guide mechanism composed of a louver 64 for adjusting the vertical air outlet direction of the indoor unit 3 and a swing-leaf assembly 63 for adjusting the lateral air outlet direction of the indoor unit 3 in addition to the above-mentioned indoor heat exchanger 16 and the fan 31. The air conditioner 1 further includes a remote controller 5. The remote controller 5 has Figure 1 The liquid crystal display device 5a and the buttons 5b are shown. The user can operate the switches using the corresponding buttons 5b of the operation switch, the temperature setting switch, the air direction setting switch, the air volume setting switch, and the thermal stress comfort function, etc.

[0078] The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and supplies refrigerant to the air that has been adjusted and heat-exchanged. The compressor 11 compresses the refrigerant gas in a high-temperature and high-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 heat is released to the surrounding environment through the condensation process. The electronic expansion valve 14 expands the liquid-phase refrigerant in a high-temperature and high-pressure state condensed in the condenser into low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the electronic expansion valve 14 and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor 11. The evaporator can achieve a refrigeration effect by heat exchange with the material to be cooled using the latent heat of evaporation of the refrigerant. Throughout the cycle, the air conditioner 1 can adjust the temperature of the indoor space.

[0079] The pressure switch 12 can be provided on the suction and discharge pipeline of the compressor 11, and the pressure switch 12 has a first state and a second state, and is specifically configured to detect the pressure value in the refrigeration system, and switch to the first state when the detected pressure value is greater than a preset pressure threshold, and switch to the second state when the detected pressure value is less than or equal to the preset pressure threshold.

[0080] Referring to Figure 4 The air conditioner 1 provided by the embodiment of the present application further includes a controller 20; the controller 20 is connected with the compressor 11 to control the operation of the compressor 11; and the compressor 11 is further connected with the pressure switch 12 to obtain the state of the pressure switch 12. The controller 20 is configured to, in a case where the start-up time length of the compressor 11 is less than a first preset time length, control the operation frequency of the compressor 11 to decrease by a preset frequency value each time a preset high-pressure condition is detected; wherein the preset high-pressure condition is that the pressure switch 12 switches from the second state to the first state and the holding time of the first state reaches a second preset time length.

[0081] Specifically, referring to Figure 5The working process of the air conditioner 1 is as follows: the compressor 11 is started (step S10); the controller 20 determines the relationship between the starting time of the compressor 11 and the first preset time (step S11); when the starting time of the compressor 11 is less than the first preset time, the controller 20 detects whether the preset high-pressure condition is met in real time (step S12), wherein the preset high-pressure condition is that the pressure switch 12 is switched from the second state to the first state and the holding time in the first state reaches the second preset time; whenever the preset high-pressure condition is met, it means that the current condensing pressure of the refrigeration system is too large, at this time, the running frequency of the compressor 11 is controlled to be reduced by a preset frequency value (step S13), so as to reduce the current condensing pressure.

[0082] It should be noted that the first preset time, the second preset time and the preset frequency value can be set according to actual needs, which are not limited here. Optionally, the first preset time is 5 min, the second preset time is 5 s, and the preset frequency value is 3 hz.

[0083] Compared with the prior art, the air conditioner 1 provided in the embodiment can continuously detect whether the preset high-pressure condition is met when the starting time of the compressor 11 is less than the first preset time, that is, in the initial starting stage of the compressor 11, and whenever the action time of the pressure switch 12 switching to the first state meets the second preset time, the running frequency of the compressor 11 is controlled to be reduced by a preset frequency value, so that the refrigerant pressure can be reduced by reducing the frequency of the compressor 11, effectively avoiding system shutdown caused by pressure overshoot, thereby improving the high-temperature running capability of the air conditioner 1.

[0084] As one of the optional embodiments, see Figure 6 The air conditioner 1 further comprises a temperature detection device 30 for detecting the outdoor environment temperature; the controller 20 is connected with the temperature detection device 30 to obtain the detected outdoor environment temperature.

[0085] The controller 20 is further configured to:

[0086] When the compressor 11 is started, the current outdoor environment temperature is obtained;

[0087] According to the current outdoor environment temperature, the target frequency of the compressor 11 is determined;

[0088] The compressor 11 is controlled to run at the target frequency;

[0089] The controller 20 is further configured to: increase the high-pressure number by one when the running frequency of the compressor 11 is controlled to be reduced by the preset frequency value; wherein the initial value of the high-pressure number is zero.

[0090] The controller 20 is further configured to:

[0091] When the high pressure number is greater than one, the controller 20 controls the compressor 11 to suspend the frequency increasing operation until the preset high pressure condition is not met.

[0092] Specifically, referring to Figure 7 , the working process of the air conditioner 1 is as follows: the compressor 11 is started; the controller 20 acquires the current outdoor ambient temperature when the compressor 11 is started (step S22); the controller 20 determines the target frequency of the compressor 11 according to the current outdoor ambient temperature (step S23); the controller 20 controls the compressor 11 to operate at the target frequency (step S24); the controller 20 determines the relationship between the starting time of the compressor 11 and the first preset time (step S11); the controller 20 detects whether the preset high pressure condition is met in real time when the starting time of the compressor 11 is less than the first preset time (step S12), wherein the preset high pressure condition is that the pressure switch 12 is switched from the second state to the first state and the holding time in the first state reaches the second preset time; whenever the preset high pressure condition is met, it means that the current condensing pressure of the refrigeration system is too large, at this time, the controller 20 controls the operating frequency of the compressor 11 to decrease by a preset frequency value (step S13), so as to decrease the current condensing pressure, and the high pressure number is increased by one; when the high pressure number is greater than one, the controller 20 controls the compressor 11 to suspend the frequency increasing operation until the preset high pressure condition is not met (step S14).

[0093] In this embodiment, when the compressor 11 is started, the frequency increasing operation of the compressor 11 is controlled according to the outdoor ambient temperature, which can ensure that the refrigeration capacity matches the ambient temperature, thereby improving the high temperature operation capacity of the air conditioner 1, and if the preset high pressure condition continues to be met, the frequency increasing operation of the compressor 11 is prohibited while the frequency of the compressor 11 is decreased, thereby further avoiding pressure overshoot.

[0094] As one of the optional embodiments, the controller 20 is further configured to increase the high pressure number by one when the operating frequency of the compressor 11 is controlled to decrease by a preset frequency value; wherein the initial value of the high pressure number is zero.

[0095] Referring to Figure 8 , the refrigeration system further comprises an electronic expansion valve 14 for controlling the flow of refrigerant; the controller 20 is connected with the electronic expansion valve 14 to adjust the opening degree of the electronic expansion valve 14.

[0096] Referring to Figure 9 , the controller 20 is further configured to:

[0097] S31, when the starting time of the compressor 11 is equal to or greater than the first preset time length, determining the size relationship between the high pressure times and a preset number of times;

[0098] S32, if the high pressure times are less than or equal to the preset number of times, controlling the electronic expansion valve 14 according to a preset valve control strategy, and clearing the high pressure times;

[0099] S33, if the high pressure times are greater than the preset number of times, controlling the opening of the electronic expansion valve 14 to increase by a first preset number of steps, controlling the electronic expansion valve 14 according to the preset valve control strategy, and clearing the high pressure times.

[0100] In this embodiment, when the starting time of the air conditioner 1 is equal to or greater than the first preset time length, that is, in the normal running stage of the compressor 11, if the number of times that the preset high pressure condition is not met is too large, the opening of the electronic expansion valve 14 is further increased under the condition that the frequency is consistent, and the system throttling is reduced, so that the protection time of the pressure switch 12 is used as a control parameter, the compressor 11 frequency and the opening of the electronic expansion valve 14 are coupled for control, and the system pressure is more accurately adjusted, and the pressure overshoot is further avoided. The first preset number of steps can be 50 steps.

[0101] Further, the controller 20 is further configured to:

[0102] When the compressor 11 is started, the current outdoor environment temperature is obtained;

[0103] According to the current outdoor environment temperature, the target opening of the electronic expansion valve 14 is determined;

[0104] The electronic expansion valve 14 is controlled to adjust to the target opening.

[0105] Therefore, when the compressor 11 is started, the initial opening of the electronic expansion valve 14 is controlled according to the outdoor environment temperature, which can ensure that the refrigeration capacity matches the environment temperature, thereby improving the high temperature running ability of the air conditioner 1.

[0106] Further, the valve control strategy comprises:

[0107] The target discharge temperature and the current discharge temperature of the electronic expansion valve 14 are obtained;

[0108] According to the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve 14, the electronic expansion valve 14 is controlled.

[0109] In the embodiment, the target discharge temperature can be calculated according to the preset temperature of the air conditioner 1, and the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve 14 can well reflect whether the refrigeration system meets the refrigeration demand, so that the electronic expansion valve 14 is controlled according to the difference, which can ensure the capacity of the refrigeration system while avoiding pressure overshoot.

[0110] Further, the opening degree control of the electronic expansion valve 14 according to the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve 14 comprises:

[0111] When the difference is greater than a first preset difference and the duration reaches a third preset time length, the electronic expansion valve 14 is controlled to close at a first speed;

[0112] When the difference is greater than a second preset difference and the duration reaches a third preset time length, the electronic expansion valve 14 is controlled to close at a second speed; wherein the second preset difference is less than the first preset difference, and the second speed is less than the first speed;

[0113] When the difference is between the second preset difference and a third preset difference and the duration reaches a third preset time length, the electronic expansion valve 14 is controlled to close at a third speed; wherein the third preset difference is less than the second preset difference, and the third speed is less than the second speed.

[0114] It should be noted that the first preset difference, the second preset difference, the third preset difference, the first speed, the second speed and the third speed can be set according to actual needs, which are not limited herein.

[0115] Optionally, the first preset difference is 5, the second preset difference is 3, the third preset difference is -3, the first speed is 2 steps / 5s, the second speed is 2 steps / 20s, and the third speed is 2 steps / 60s. Specifically, assuming that the target discharge temperature is Pd0 and the current discharge temperature is Pd, if Pd0-Pd>5 and the duration is maintained for 5s, the electronic expansion valve 14 is closed at 2 steps / 5s; if Pd0-Pd>3 and the duration is maintained for 5s, the electronic expansion valve 14 is closed at 2 steps / 20s; and if 3>Pd0-Pd>-3 and the duration is maintained for 5s, the electronic expansion valve 14 is closed and opened at 2 steps / 60s.

[0116] In the embodiment, the greater the difference, the faster the closing speed of the valve is controlled, which can shorten the time consumption to reach the target discharge temperature, thereby improving the capacity of the refrigeration system; and the smaller the difference, the closer to the target temperature, so as to avoid system pressure overshoot by reducing the speed to avoid the valve closing too fast and causing system pressure overshoot.

[0117] Further, referring to Figure 10 , the controller 20 is further configured to:

[0118] S41, in the case where the compressor 11 is started for a time equal to or greater than the first preset time, whenever the preset high pressure condition is detected to be met, the opening degree of the electronic expansion valve 14 is controlled to increase by a second preset step.

[0119] In this embodiment, if the preset high pressure condition is met, the opening degree of the electronic expansion valve 14 is increased, thereby reducing the system throttling and reducing the system pressure, and avoiding pressure overshoot.

[0120] Further, referring to Figure 11 , the controller 20 is further configured to increase the high pressure number by one while controlling the opening degree of the electronic expansion valve 14 to increase by the second preset step.

[0121] The controller 20 is further configured to:

[0122] S42, when the high pressure number is greater than one, the electronic expansion valve 14 is controlled according to the preset valve control strategy is suspended until the preset high pressure condition is not met.

[0123] In this embodiment, if the preset high pressure condition is met multiple times during the normal operation stage of the compressor 11, the electronic expansion valve 14 is controlled according to the preset valve control strategy is suspended, thereby avoiding the increase of system throttling caused by valve closing and leading to the increase of system pressure.

[0124] It should be noted that in the prior art, according to the characteristics of R410A refrigerant, a pressure switch 12 with a pressure of 4.15Mpa is selected, leaving a pressure margin, and the highest environment is 57℃. With the expansion of the demand of the Saudi market, there is still a demand for refrigeration in an environment of 57℃, or even 61-63℃. Thus, the air conditioner 1 that can only run at 57℃ no longer meets the user's usage requirements, and the pressure needs to be further increased to fully utilize the pressure space. The air conditioner 1 provided in the embodiment of the present application distinguishes between the start-up and running stages, uses frequency and pressure switch 12 time control in the start-up stage, and uses electronic expansion valve 14 and pressure switch 12 time control in the running stage, which can maximize the use of pressure space during operation, solve the problem of narrow pressure range caused by pressure and environmental fluctuations, improve high temperature adaptability, and can increase the maximum running temperature from 57℃ to 63℃.

[0125] Correspondingly, another embodiment of the present application provides a control method of an air conditioner, wherein a refrigeration system of the air conditioner comprises a compressor and a pressure switch; the compressor is used for compressing refrigerant; the pressure switch is used for detecting a pressure value in the refrigeration system, and switches to a first state when detecting that the pressure value is greater than a preset pressure threshold value, and switches to a second state when detecting that the pressure value is less than or equal to the preset pressure threshold value; the method comprises:

[0126] In a case where the starting time length of the compressor is less than a first preset time length, whenever a preset high-pressure condition is detected to be met, the running frequency of the compressor is controlled to be reduced by a preset frequency value; wherein the preset high-pressure condition is that the pressure switch switches from the second state to the first state and the holding time in the first state reaches a second preset time length.

[0127] Compared with the prior art, the control method of the air conditioner provided by the embodiment can reduce the refrigerant pressure by reducing the frequency of the compressor when the starting time length of the compressor is less than the first preset time length, that is, in the initial starting stage of the compressor, and whenever the action time of the pressure switch switching to the first state meets the second preset time length, the running frequency of the compressor is controlled to be reduced by the preset frequency value, thereby effectively avoiding system shutdown caused by pressure overshoot, and improving the high-temperature operation capability of the air conditioner.

[0128] As an improvement of the above-mentioned scheme, the method further comprises:

[0129] When the running frequency of the compressor is controlled to be reduced by the preset frequency value, the high-pressure number is increased by one; wherein the initial value of the high-pressure number is zero;

[0130] The refrigeration system further comprises an electronic expansion valve used for controlling the flow of refrigerant.

[0131] The method further comprises:

[0132] When the compressor is started, the current outdoor environment temperature is obtained;

[0133] According to the current outdoor environment temperature, the target opening degree of the electronic expansion valve is determined;

[0134] The electronic expansion valve is controlled to be adjusted to the target opening degree;

[0135] When the starting time length of the compressor is equal to or greater than the first preset time length, the size relationship between the high-pressure number and a preset number is judged;

[0136] If the high-pressure number is less than or equal to the preset number, the electronic expansion valve is controlled according to a preset valve control strategy, and the high-pressure number is cleared;

[0137] If the high pressure frequency is greater than the preset frequency, the opening of the electronic expansion valve is controlled to increase by a first preset step, the electronic expansion valve is controlled according to a preset valve control strategy, and the high pressure frequency is cleared.

[0138] In the embodiment, when the starting time of the air conditioner is equal to or greater than a first preset time, that is, in the normal operation stage of the compressor, if the number of times that the preset high pressure condition is not met is too large, the opening of the electronic expansion valve is further increased in the case of consistent frequency, the throttling of the system is reduced, and the protection time of the pressure switch is taken as a control parameter to control the coupling of the compressor frequency and the opening of the electronic expansion valve, so as to more accurately adjust the system pressure and further avoid pressure overshoot.

[0139] Further, the valve control strategy comprises:

[0140] The target discharge temperature and the current discharge temperature of the electronic expansion valve are obtained.

[0141] The electronic expansion valve is controlled according to the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve.

[0142] In the embodiment, the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve can well reflect whether the refrigeration system meets the refrigeration demand, so that the electronic expansion valve is controlled according to the difference, the capacity of the refrigeration system can be ensured, and pressure overshoot can be avoided.

[0143] Further, the opening control of the electronic expansion valve according to the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve comprises:

[0144] When the difference is greater than a first preset difference and the duration reaches a third preset time, the electronic expansion valve is controlled to close at a first speed;

[0145] When the difference is greater than a second preset difference and the duration reaches a third preset time, the electronic expansion valve is controlled to close at a second speed; wherein the second preset difference is less than the first preset difference, and the second speed is less than the first speed.

[0146] When the difference is between the second preset difference and the third preset difference, and the duration reaches a third preset time, the electronic expansion valve is controlled to close at a third speed; wherein the third preset difference is less than the second preset difference, and the third speed is less than the second speed.

[0147] In the embodiment, the greater the difference is, the faster the control valve closing speed is, so that the time consumption to reach the target exhaust temperature is shortened, thereby improving the refrigeration system capacity, and the smaller the difference is, which indicates that the target temperature is approached, so that the speed is reduced to avoid the system pressure overshoot caused by the too fast valve closing.

[0148] Further, the method further comprises:

[0149] In the case that the compressor is started for a time equal to or greater than the first preset time, whenever the preset high pressure condition is detected to be met, the opening degree of the electronic expansion valve is controlled to increase by a second preset step.

[0150] In the embodiment, the opening degree of the electronic expansion valve is increased according to the preset high pressure condition, so that the system throttling is reduced, the system pressure is reduced, and the pressure overshoot is avoided.

[0151] Further, the method further comprises:

[0152] While the opening degree of the electronic expansion valve is controlled to increase by the second preset step, the high pressure number is added by one;

[0153] When the high pressure number is greater than one, the electronic expansion valve is controlled according to the preset valve control strategy is suspended until the preset high pressure condition is not met.

[0154] In the embodiment, if the preset high pressure condition is met for multiple times during the normal operation stage of the compressor, the electronic expansion valve is controlled according to the preset valve control strategy is suspended, so that the system throttling caused by the valve closing is reduced, and the system pressure is reduced.

[0155] As one of the optional embodiments, the air conditioner further comprises a temperature detection device for detecting the outdoor environment temperature;

[0156] The method further comprises:

[0157] When the compressor is started, the current outdoor environment temperature is obtained;

[0158] According to the current outdoor environment temperature, the target frequency of the compressor is determined;

[0159] The compressor is controlled to operate at the target frequency;

[0160] While the operating frequency of the compressor is controlled to be reduced by a preset frequency value, the high pressure number is added by one; wherein the initial value of the high pressure number is zero;

[0161] When the high pressure number is greater than one, the compressor is controlled to suspend the frequency increasing operation until the preset high pressure condition is not met.

[0162] In the embodiment, when the compressor is started, the compressor frequency increasing operation is controlled according to the outdoor environment temperature, so that the refrigerating capacity can be matched with the environment temperature, thereby improving the high temperature operation capacity of the air conditioner. If the preset high pressure condition is continuously detected, the compressor frequency is reduced and the compressor frequency increasing operation is prohibited, thereby further avoiding pressure overshoot.

[0163] The above is the preferred embodiment of the present application. It should be noted that those skilled in the art can make some improvements and refinements without departing from the principles of the present application, and these improvements and refinements are also considered within the protection scope of the present application.

Claims

1. An air conditioner characterized by comprising: The application relates to a refrigeration system, a control method and an air conditioner. The refrigeration system comprises a compressor and a pressure switch. The compressor is used for compressing refrigerant. The pressure switch is used for detecting a pressure value in the refrigeration system and switching to a first state when the detected pressure value is greater than a preset pressure threshold value and switching to a second state when the detected pressure value is less than or equal to the preset pressure threshold value. A controller is used for reducing the operating frequency of the compressor by a preset frequency value every time a preset high-pressure condition is met when the starting time of the compressor is less than a first preset time length; wherein the preset high-pressure condition is that the pressure switch switches from the second state to the first state and the holding time of the first state reaches a second preset time length. The controller is also used for increasing the high-pressure number by one when the operating frequency of the compressor is reduced by the preset frequency value; wherein the initial value of the high-pressure number is zero. The refrigeration system further comprises an electronic expansion valve used for controlling the flow of refrigerant. The controller is also used for: When the starting time of the compressor is equal to or greater than the first preset time length, determining the size relationship between the high-pressure number and a preset number. If the high-pressure number is less than or equal to the preset number, controlling the electronic expansion valve according to a preset valve control strategy and clearing the high-pressure number. If the high-pressure number is greater than the preset number, increasing the opening degree of the electronic expansion valve by a first preset step number, controlling the electronic expansion valve according to the preset valve control strategy and clearing the high-pressure number.

2. The air conditioner of claim 1, wherein The air conditioner further comprises a temperature detection device used for detecting the outdoor environment temperature. The controller is also used for: When the compressor is started, obtaining the current outdoor environment temperature. According to the current outdoor environment temperature, determining the target frequency of the compressor. Controlling the compressor to operate at the target frequency. When the high-pressure number is greater than one, controlling the compressor to suspend the frequency increase operation until the preset high-pressure condition is not met. The valve control strategy comprises: Obtaining the target discharge temperature and the current discharge temperature of the electronic expansion valve.

3. The air conditioner of claim 1, wherein Controlling the electronic expansion valve according to the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve. The opening degree control of the electronic expansion valve according to the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve comprises: When the difference is greater than a first preset difference value and the duration reaches a third preset time length, controlling the electronic expansion valve to close the valve at a first speed.

4. The air conditioner of claim 3, wherein When the difference is greater than a second preset difference value and the duration reaches a third preset time length, controlling the electronic expansion valve to close the valve at a second speed; wherein the second preset difference value is less than the first preset difference value and the second speed is less than the first speed. ​ ​ When the difference is between a second preset difference and a third preset difference, and the duration reaches a third preset time length, the electronic expansion valve is controlled to close at a third speed; wherein the third preset difference is smaller than the second preset difference, and the third speed is smaller than the second speed.

5. The air conditioner of claim 1, wherein The controller is further configured to: When the start-up time length of the compressor is equal to or greater than the first preset time length, the opening degree of the electronic expansion valve is increased by a second preset step number each time the preset high-pressure condition is detected.

6. The air conditioner of claim 5, wherein The controller is further configured to: When the high-pressure number is greater than one, the control of the electronic expansion valve according to the preset valve control strategy is suspended until the preset high-pressure condition is not met.

7. A control method of an air conditioner, characterized by, The refrigeration system of the air conditioner comprises a compressor and a pressure switch; the compressor is configured to compress refrigerant; The pressure switch is configured to detect the pressure value in the refrigeration system, and is switched to a first state when the detected pressure value is greater than a preset pressure threshold, and is switched to a second state when the detected pressure value is less than or equal to the preset pressure threshold; the method comprises: When the start-up time length of the compressor is less than the first preset time length, the operating frequency of the compressor is reduced by a preset frequency value each time the preset high-pressure condition is detected; wherein the preset high-pressure condition is that the pressure switch is switched from the second state to the first state and the holding time of the first state reaches the second preset time length; The high-pressure number is increased by one while the operating frequency of the compressor is reduced by the preset frequency value; wherein the initial value of the high-pressure number is zero; The refrigeration system further comprises an electronic expansion valve configured to control the flow of refrigerant; When the start-up time length of the compressor is equal to or greater than the first preset time length, the relationship between the high-pressure number and a preset number is determined; If the high-pressure number is less than or equal to the preset number, the electronic expansion valve is controlled according to the preset valve control strategy, and the high-pressure number is cleared; If the high-pressure number is greater than the preset number, the opening degree of the electronic expansion valve is increased by a first preset step number, the electronic expansion valve is controlled according to the preset valve control strategy, and the high-pressure number is cleared.

8. The control method of claim 7, wherein, The valve control strategy comprises: The target discharge temperature and the current discharge temperature of the electronic expansion valve are obtained; The electronic expansion valve is controlled according to the difference between the target discharge temperature and the current discharge temperature of the electronic expansion valve.

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