Air conditioner and control method of air conditioner

Abstract

The invention discloses an air conditioner and a control method of the air conditioner, and the air conditioner comprises a refrigerant loop which enables a refrigerant to circulate in a loop composed of a compressor, a condenser, an electronic expansion valve and an evaporator; the low-voltage pressure switch is used for performing low-voltage protection on the air conditioner; the controller is used for acquiring the running time of the compressor after the air conditioner finishes defrosting and is switched into a heating mode; determining an opening degree adjusting rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the operation time of the compressor sequentially reaches each of a plurality of preset time points; wherein the plurality of time points are determined according to preset low-voltage protection time; and the current opening degree of the electronic expansion valve is adjusted according to the determined opening degree adjusting rule. According to the technical scheme, after the air conditioner is heated and defrosted, the refrigerant flow can be increased by adjusting the opening degree of the electronic expansion valve, and therefore low-pressure faults are avoided.

Description

TECHNICAL FIELD

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

[0002] Commercial air conditioners or large-capacity air conditioners are generally provided with a low-pressure switch for protecting the reliable operation of the compressor. For example, in the case of insufficient refrigerant, leakage of the opening valve, and dirty pipeline of the air conditioning refrigeration system, the compressor cannot suck in sufficient refrigerant, which can cause the internal lubricating oil of the compressor to fail to flow, resulting in poor lubrication and damage to the compressor. When the low-pressure side of the compressor is insufficient in refrigerant, the low-pressure is very low, which meets the protection condition of the low-pressure switch, and the low-pressure switch is triggered to start the low-pressure protection, which can avoid damage to the compressor and abnormal operation of the compressor.

[0003] When the air conditioner is in heating operation, especially when the outdoor environment temperature is lower than 7℃, the evaporation temperature of the air conditioner is low, and the outdoor heat exchanger is prone to frost formation. The longer the air conditioner runs, the more frost is formed, and the frost can affect the heat exchange effect of the air conditioner and cause the heating performance to decrease. Therefore, the air conditioner must be defrosted to obtain good heating effect. The traditional method is to defrost by switching from heating operation to refrigeration operation. After the air conditioner is defrosted, it is switched from refrigeration operation back to heating operation. At this time, most of the refrigerant is stored in the outdoor heat exchanger in the form of liquid and cannot participate in the refrigeration cycle system in the form of gas. The low-pressure of the refrigeration system is very low, which can easily meet the protection condition of the low-pressure switch and trigger the low-pressure protection.

[0004] In order to avoid the low-pressure protection after the air conditioner is defrosted in heating operation, the existing technology mainly controls the air conditioner electrical system to shield the low-pressure fault for a long time. During the shielding period, even if a low-pressure fault occurs, the low-pressure protection is not triggered, and the air conditioner does not stop running. However, this can cause the air conditioning refrigeration system to lack low-pressure protection for a long time, especially in the case of insufficient refrigerant, leakage of the opening valve, and dirty pipeline, which can cause the compressor to be damaged due to the failure of the low-pressure protection. SUMMARY

[0005] The purpose of the embodiments of the present application is to provide an air conditioner and a control method of the air conditioner. After the air conditioner is defrosted in heating operation, the low-pressure protection time is set, and the opening degree of the electronic expansion valve is adjusted based on the time points set according to the low-pressure protection time, which can improve the refrigerant flow and avoid the low-pressure fault caused by the low pressure on the low-pressure side.

[0006] In order to achieve the above-mentioned purpose, the embodiments of the present application provide an air conditioner, which comprises:

[0007] A refrigerant circuit, which circulates refrigerant in a circuit composed of a compressor, a condenser, an electronic expansion valve, and an evaporator, one of the condenser and the evaporator being an outdoor heat exchanger and the other being an indoor heat exchanger;

[0008] A low-pressure pressure switch for low-pressure protection of the air conditioner;

[0009] A controller for:

[0010] After the air conditioner finishes defrosting and turns into a heating mode, obtaining a running time of the compressor;

[0011] According to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points in turn, determining an opening degree adjustment rule of the electronic expansion valve; wherein the plurality of time points are determined according to a preset low-pressure protection time;

[0012] According to the determined opening degree adjustment rule, adjusting a current opening degree of the electronic expansion valve.

[0013] Further, the controller determines the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points in turn, specifically including:

[0014] When the running time of the compressor reaches a preset first time point, determining whether the low-pressure pressure switch is in an off state; wherein the first time point = the low-pressure protection time - a preset first low-pressure early warning time;

[0015] If yes, recording a protection number of the low-pressure pressure switch, and determining the opening degree adjustment rule of the electronic expansion valve as increasing to a first preset opening degree;

[0016] If no, determining the opening degree adjustment rule of the electronic expansion valve as keeping a current opening degree.

[0017] Further, the controller determines the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points in turn, further including:

[0018] When the running time of the compressor reaches a preset second time point, determining whether the low-pressure pressure switch is in an off state; wherein the second time point = the low-pressure protection time - a preset second low-pressure early warning time;

[0019] If yes, updating the protection number of the low-pressure pressure switch, and determining the opening degree adjustment rule of the electronic expansion valve as increasing to a second preset opening degree;

[0020] If no, it is determined that the opening degree adjustment rule of the electronic expansion valve is to keep the current opening degree.

[0021] Further, the controller determines the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points in turn, and the determination further comprises:

[0022] When the running time of the compressor reaches a preset third time point, it is determined whether the low-pressure pressure switch is in an open state; wherein the third time point = the low-pressure protection time - a preset third low-pressure early warning time.

[0023] If yes, the protection number of the low-pressure pressure switch is updated, and the opening degree adjustment rule of the electronic expansion valve is determined according to the updated protection number;

[0024] If no, it is determined that the opening degree adjustment rule of the electronic expansion valve is to keep the current opening degree.

[0025] Further, the controller determines the opening degree adjustment rule of the electronic expansion valve according to the updated protection number, and specifically comprises:

[0026] It is determined whether the updated protection number reaches a preset protection number threshold;

[0027] If yes, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase to the maximum opening degree;

[0028] If no, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase to a third preset opening degree.

[0029] Further, the controller determines the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points in turn, and the determination further comprises:

[0030] When the running time of the compressor reaches a preset fourth time point, it is determined whether the low-pressure pressure switch is in an open state; wherein the fourth time point = the low-pressure protection time - a preset low-pressure change time.

[0031] If yes, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase to the maximum opening degree;

[0032] If no, it is determined that the opening degree adjustment rule of the electronic expansion valve is to keep the current opening degree.

[0033] Further, 1≤ the third low pressure early warning time < the second low pressure early warning time < the first low pressure early warning time ≤ the low pressure protection time - the low pressure change time.

[0034] Further, the air conditioner further comprises:

[0035] A bypass circuit is arranged between the outlet of the outdoor heat exchanger and the suction port of the compressor, and an electromagnetic valve is arranged on the bypass circuit.

[0036] The controller determines the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low pressure switch when the operation time of the compressor reaches each of a plurality of preset time points in sequence, and specifically comprises:

[0037] When the operation time of the compressor reaches a fourth preset time point, it is judged whether the low pressure switch is in an open state; wherein the fourth preset time point = the low pressure protection time - a preset low pressure change time.

[0038] If yes, the opening degree adjustment rule of the electronic expansion valve is determined as increasing to the maximum opening degree, and the electromagnetic valve is controlled to change from a closed state to an open state;

[0039] If no, the opening degree adjustment rule of the electronic expansion valve is determined as keeping the current opening degree.

[0040] In order to achieve the above-mentioned purpose, the embodiment of the present application further provides a control method of an air conditioner, the air conditioner comprising:

[0041] A refrigerant circuit is arranged to circulate refrigerant in a circuit composed of a compressor, a condenser, an electronic expansion valve and an evaporator, one of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger;

[0042] A low pressure switch is arranged to protect the air conditioner from low pressure;

[0043] The method comprises:

[0044] After the air conditioner finishes defrosting and turns into a heating mode, the operation time of the compressor is obtained;

[0045] The opening degree adjustment rule of the electronic expansion valve is determined according to the on-off state of the low pressure switch when the operation time of the compressor reaches each of a plurality of preset time points in sequence; wherein the plurality of time points are determined according to a preset low pressure protection time.

[0046] The current opening degree of the electronic expansion valve is adjusted according to the determined opening degree adjustment rule.

[0047] Further, the air conditioner further comprises:

[0048] A bypass circuit is arranged between the outlet of the outdoor heat exchanger and the suction port of the compressor, and an electromagnetic valve is arranged on the bypass circuit.

[0049] The opening degree adjustment rule of the electronic expansion valve is determined according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points in sequence, and specifically comprises:

[0050] When the running time of the compressor reaches a fourth preset time point, it is judged whether the low-pressure pressure switch is in an off state; wherein the fourth time point = the low-pressure protection time - a preset low-pressure change time.

[0051] If yes, the opening degree adjustment rule of the electronic expansion valve is determined as increasing to the maximum opening degree, and the electromagnetic valve is controlled to change from a closed state to an open state;

[0052] If no, the opening degree adjustment rule of the electronic expansion valve is determined as keeping the current opening degree.

[0053] Compared with the prior art, the air conditioner and the control method thereof provided by the embodiment of the present application, the air conditioner comprises: a refrigerant circuit, which circulates refrigerant in a circuit composed of a compressor, a condenser, an electronic expansion valve and an evaporator, one of the condenser and the evaporator being an outdoor heat exchanger and the other being an indoor heat exchanger; a low-pressure pressure switch for low-pressure protection of the air conditioner; a controller for: obtaining the running time of the compressor after the air conditioner defrosting ends and turns into a heating mode; determining the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points in sequence, wherein the plurality of time points are determined according to a preset low-pressure protection time; and adjusting the current opening degree of the electronic expansion valve according to the determined opening degree adjustment rule. After the air conditioner defrosting, the embodiment of the present application sets the low-pressure protection time and sets a plurality of time points based on the low-pressure protection time to adjust the opening degree of the electronic expansion valve, which can improve the refrigerant flow, thereby avoiding low-pressure failure due to low pressure on the low-pressure side. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a schematic diagram of the appearance structure of an air conditioner provided by an embodiment of the present application;

[0055] Figure 2 is a schematic diagram of the internal structure of an air conditioner provided by an embodiment of the present application;

[0056] Figure 3is a working flow chart of a controller of an air conditioner provided by an embodiment of the present application;

[0057] Figure 4 is a working flow chart of a controller of an air conditioner provided by another embodiment of the present application;

[0058] Figure 5 is a working flow chart of a controller of an air conditioner provided by still another embodiment of the present application;

[0059] Figure 6 is a working flow chart of a controller of an air conditioner provided by still another embodiment of the present application;

[0060] Figure 7 is a working flow chart of a controller of an air conditioner provided by still another embodiment of the present application;

[0061] Figure 8 is a schematic diagram of an internal structure of an air conditioner provided by another embodiment of the present application;

[0062] Figure 9 is a working flow chart of a controller of an air conditioner provided by still another embodiment of the present application;

[0063] Figure 10 is a working example flow chart of a controller of an air conditioner provided by an embodiment of the present application;

[0064] Figure 11 is a working example flow chart of a controller of an air conditioner provided by another embodiment of the present application. DETAILED DESCRIPTION

[0065] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, any other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0066] Referring to Figure 1 shown is a schematic diagram of an external structure of an air conditioner provided by an embodiment of the present application, the external structure of the air conditioner comprises an indoor unit 100 and an outdoor unit 200, wherein the indoor unit 100 is used to adjust the temperature and humidity of indoor air, the outdoor unit 200 is connected with the indoor unit 100 through a connection pipe, and the indoor unit 100 is generally installed indoors, and the outdoor unit 200 is generally installed outdoors.

[0067] combined with Figure 2As shown in the figure, the air conditioner provided by the embodiment of the present application comprises a refrigerant circuit, and the refrigerant circulates in the circuit composed of the compressor 1, the condenser, the electronic expansion valve 4 and the evaporator, wherein one of the condenser and the evaporator is the outdoor heat exchanger 3, and the other is the indoor heat exchanger 5.

[0068] In combination Figure 2 As shown in the figure, in the embodiment of the present application, the air conditioner comprises a refrigerant circuit, and the refrigerant circulates in the circuit composed of the compressor 1, the condenser, the electronic expansion valve 4 and the evaporator, wherein one of the condenser and the evaporator is the outdoor heat exchanger 3, and the other is the indoor heat exchanger 5.

[0069] It should be noted that, Figure 2 The solid arrow in the figure represents the flow direction of the refrigerant in the refrigeration cycle, and the dashed arrow represents the flow direction of the refrigerant in the heating cycle.

[0070] In combination Figure 2 As shown in the figure, in the embodiment of the present application, the air conditioner further comprises a low-pressure pressure switch 6 and its related pipeline, and the low-pressure pressure switch 6 is used for low-pressure protection of the air conditioner. In the normal state, the low-pressure pressure switch 6 is in the closed state, and in the protection state, the low-pressure pressure switch 6 is in the open state. The control principle of the low-pressure protection is generally as follows: when it is detected that the low-pressure side pressure of the compressor 1 is lower than PS1, the contact of the low-pressure pressure switch 6 is disconnected, at this time, the low-pressure pressure switch 6 is in the protection state; when it is detected that the low-pressure side pressure of the compressor 1 is higher than PS2, the low-pressure pressure switch 6 recovers from the protection state to the normal state (i.e. from the open state to the closed state), wherein PS1 and PS2 are the pre-set low-pressure pressure thresholds, and PS2> PS1 is satisfied.

[0071] Understandably, in order to achieve low-pressure protection, the air conditioner also includes a pressure sensor, which is used to detect the low-pressure side pressure of compressor 1 in real time, so as to determine whether the low-pressure side pressure meets the low-pressure protection conditions (i.e., whether the low-pressure side pressure is lower than PS1).

[0072] In this embodiment of the invention, the air conditioner further includes a controller, which is connected to the low-pressure switch 6 and the pressure sensor to control the on / off state of the low-pressure switch 6 based on the low-pressure side pressure data detected by the pressure sensor. Furthermore, the controller is also used to control the operation of various components in the air conditioner, so that the various components of the air conditioner operate to realize the various functions of the air conditioner.

[0073] As described in the background section, after defrosting in heating mode, an air conditioner switches back to heating mode. During the initial period after starting heating mode, the compressor continuously draws in air, causing the low-pressure side pressure of the air conditioning system to be very low, which easily meets the low-pressure protection conditions and triggers low-pressure protection. By adopting the technical solution provided in this embodiment of the invention, a low-pressure protection time is set in the air conditioner, and several time points are set based on the low-pressure protection time to continuously optimize the opening of the electronic expansion valve, which can increase the refrigerant flow and thus fundamentally avoid low-pressure faults caused by low low-pressure side pressure.

[0074] As one optional embodiment, the controller is used for:

[0075] After the air conditioner finishes defrosting and switches to heating mode, the running time of the compressor is obtained;

[0076] The opening adjustment rule of the electronic expansion valve is determined based on the on / off state of the low-pressure switch at each of a preset number of time points when the compressor's operating time sequentially reaches these points; wherein, the preset number of time points are determined based on a preset low-pressure protection time.

[0077] The current opening of the electronic expansion valve is adjusted according to the determined opening adjustment rules.

[0078] Combination Figure 3 The diagram shown is a flowchart of the operation of an air conditioner controller according to an embodiment of the present invention. In a specific implementation of this embodiment, the controller operates as follows: After the air conditioner finishes defrosting, it switches to heating mode. Figure 3 Step S11 (as shown); Start timing from when the air conditioner starts heating mode to obtain the compressor's running time ( Figure 3The step S12) is shown; as the running time of the compressor increases, the running time of the compressor reaches each of a plurality of preset time points in turn, and when the running time of the compressor reaches each of the plurality of preset time points, the opening degree adjustment rule of the electronic expansion valve is determined according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of the plurality of preset time points (that is, whether it belongs to the protection state) Figure 3 The step S13) is shown; wherein the plurality of time points are determined according to the preset low-pressure protection time, and the plurality of time points are within the preset low-pressure protection time, that is, a plurality of time points for adjusting the opening degree of the electronic expansion valve are set within the preset low-pressure protection time; after determining the opening degree adjustment rule of the electronic expansion valve corresponding to each of the time points, the current opening degree of the electronic expansion valve can be adjusted according to the determined opening degree adjustment rule Figure 3 The step S14) is shown.

[0079] It should be noted that in order to prevent the refrigerant flow from being further reduced, in the embodiment of the present application, the opening degree adjustment rule of the electronic expansion valve does not reduce the opening degree of the electronic expansion valve, and as can be known from the following embodiments, when the opening degree of the electronic expansion valve is actually adjusted according to the determined opening degree adjustment rule, the opening degree of the electronic expansion valve is either increased or remains unchanged.

[0080] It should be noted that the embodiment of the present application presets a low-pressure protection time, and preferably, the value of the low-pressure protection time ranges from 120 seconds to 600 seconds.

[0081] The air conditioner provided by the embodiment of the present application comprises: a refrigerant circuit, which circulates refrigerant in a circuit composed of a compressor, a condenser, an electronic expansion valve and an evaporator, one of the condenser and the evaporator being an outdoor heat exchanger and the other being an indoor heat exchanger; a low-pressure pressure switch for low-pressure protection of the air conditioner; and a controller configured to: obtain the running time of the compressor after the air conditioner switches to a heating mode after defrosting; determine the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points, wherein the plurality of time points are determined according to a preset low-pressure protection time; and adjust the current opening degree of the electronic expansion valve according to the determined opening degree adjustment rule. The embodiment of the present application can improve the refrigerant flow by setting a low-pressure protection time and adjusting the opening degree of the electronic expansion valve based on the low-pressure protection time after the air conditioner defrosts in the heating mode, thereby avoiding low-pressure failure due to low pressure on the low-pressure side.

[0082] As one of the optional embodiments, the controller determines the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points in sequence, and specifically comprises:

[0083] When the running time of the compressor reaches a preset first time point, it is judged whether the low-pressure pressure switch is in the off state; wherein the first time point = the low-pressure protection time - a preset first low-pressure early warning time.

[0084] If yes, the protection times of the low-pressure pressure switch are recorded, and the opening degree adjustment rule of the electronic expansion valve is determined to be increased to a first preset opening degree.

[0085] If no, the opening degree adjustment rule of the electronic expansion valve is determined to be kept at the current opening degree.

[0086] In combination with Figure 4 , it is a working flow chart of a controller of an air conditioner provided by another embodiment of the present application. On the basis of the above-mentioned embodiment, when the controller executes step S13 shown in Figure 3 , it can first judge whether the running time of the compressor reaches a preset first time point (step S1311 shown in Figure 4 ); if it is judged that the running time of the compressor has not reached the preset first time point, it continues to wait for the next judgment; if it is judged that the running time of the compressor reaches the preset first time point, it further judges whether the low-pressure pressure switch is in the off state (step S1312 shown in Figure 4 ); if it is judged that the low-pressure pressure switch is in the off state, the protection times of the low-pressure pressure switch are recorded, and the opening degree adjustment rule of the electronic expansion valve is determined to be: increasing the opening degree of the electronic expansion valve from the current opening degree to a first preset opening degree (step S1313 shown in Figure 4 ); if it is judged that the low-pressure pressure switch is not in the off state, the opening degree adjustment rule of the electronic expansion valve is determined to be: keeping the opening degree of the electronic expansion valve unchanged (step S1314 shown in Figure 4 ).

[0087] It should be noted that the present embodiment further presets a first low-pressure early warning time, and the first time point = the low-pressure protection time - the first low-pressure early warning time.

[0088] It should be noted that, in the embodiments of the present invention, the opening degree of the electronic expansion valve can be increased from the current opening degree to the first preset opening degree by increasing the first preset number of steps; for example, assuming that the current opening degree of the electronic expansion valve is P0, the first preset number of steps is △P1, and the first preset opening degree is P1, then P1=P0+△P1; preferably, the value range of △P1 is 20 steps to 100 steps.

[0089] As one optional embodiment, the controller determines the opening adjustment rule of the electronic expansion valve based on the on / off state of the low-pressure switch when the compressor's operating time sequentially reaches each of a preset number of time points, and further includes:

[0090] When the compressor's operating time reaches a preset second time point, it is determined whether the low-pressure switch is in the off state; wherein, the second time point = the low-pressure protection time - the preset second low-pressure warning time;

[0091] If so, update the protection count of the low-pressure switch and determine that the opening adjustment rule of the electronic expansion valve is to increase to the second preset opening.

[0092] If not, then the opening adjustment rule of the electronic expansion valve is determined to maintain the current opening.

[0093] Combination Figure 5 The diagram shown is a flowchart of the operation of an air conditioner controller according to another embodiment of the present invention. Based on the above embodiments, in specific implementation of this embodiment, the controller executes... Figure 3 In step S13, after processing the first time point, it can be further determined whether the compressor's running time has reached the preset second time point. Figure 5 (See step S1321); If it is determined that the compressor's running time has not yet reached the preset second time point, then continue to wait for the next judgment; If it is determined that the compressor's running time has reached the preset second time point, then further determine whether the low-pressure switch is in the open state. Figure 5 (See step S1322); If it is determined that the low-pressure switch is in the open state, then update the protection count of the low-pressure switch (i.e., increment by 1), and determine the opening adjustment rule of the electronic expansion valve as follows: increase the opening of the electronic expansion valve from the current opening to the second preset opening ( Figure 5 Step S1323 (as shown); if it is determined that the low-pressure switch is not in the open state, then the opening adjustment rule of the electronic expansion valve is determined as follows: control the opening of the electronic expansion valve to maintain the current opening unchanged. Figure 5 (Step S1324 shown).

[0094] It should be noted that the embodiment of the present application also pre-provides a second low pressure early warning time, and a second time point = low pressure protection time-second low pressure early warning time.

[0095] It can be understood that when the corresponding processing is performed on the second time point, the current opening degree of the electronic expansion valve is the adjusted opening degree obtained after the corresponding processing of the first time point, and if the opening degree adjustment rule of the electronic expansion valve corresponding to the first time point is to increase the opening degree of the electronic expansion valve from the current opening degree to the first preset opening degree, the current opening degree of the electronic expansion valve corresponding to the second time point is the first preset opening degree; if the opening degree adjustment rule of the electronic expansion valve corresponding to the first time point is to control the opening degree of the electronic expansion valve to remain unchanged at the current opening degree, the current opening degree of the electronic expansion valve corresponding to the second time point is the current opening degree of the electronic expansion valve corresponding to the first time point.

[0096] It should be noted that in the embodiment of the present application, the opening degree of the electronic expansion valve can be increased from the current opening degree to the second preset opening degree by increasing the second preset step number; for example, assuming that the current opening degree of the electronic expansion valve corresponding to the first time point is P0, the first preset step number is △P1, and the first preset opening degree is P1, then P1=P0+△P1; further, assuming that the second preset step number is △P2 and the second preset opening degree is P2, then P2=P0+△P2 or P2=P1+△P2; preferably, the value range of △P2 is 20 steps to 100 steps.

[0097] As one of the optional embodiments, the controller determines the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low pressure switch when the running time of the compressor reaches each of the preset time points in turn, and the method further comprises:

[0098] When the running time of the compressor reaches a preset third time point, it is judged whether the low pressure switch is in an open state; wherein the third time point = the low pressure protection time-a preset third low pressure early warning time;

[0099] If yes, the protection number of the low pressure switch is updated, and the opening degree adjustment rule of the electronic expansion valve is determined according to the updated protection number;

[0100] If no, it is determined that the opening degree adjustment rule of the electronic expansion valve is to keep the current opening degree unchanged.

[0101] In combination with Figure 6 It is shown that the controller of the air conditioner provided by another embodiment of the present application is a working flow chart, and on the basis of the above-mentioned embodiment, the controller in the embodiment of the present application performs Figure 3In step S13, after processing the second time point, it can be further determined whether the compressor's running time has reached the preset third time point. Figure 6 (See step S1331); If it is determined that the compressor's running time has not yet reached the preset third time point, then continue to wait for the next judgment; If it is determined that the compressor's running time has reached the preset third time point, then further determine whether the low-pressure switch is in the open state. Figure 6 (See step S1332); If it is determined that the low-pressure switch is in the open state, then update the protection count of the low-pressure switch (i.e., increment by 1), and further determine the opening adjustment rule of the electronic expansion valve based on the updated protection count. Figure 6 (See step S1333); If it is determined that the low-pressure switch is not in the open state, then the opening adjustment rule of the electronic expansion valve is determined as follows: control the opening of the electronic expansion valve to maintain the current opening unchanged. Figure 6 (Step S1334 shown).

[0102] It should be noted that, in this embodiment of the invention, a third low-pressure warning time is also preset, and there is a third time point = low-pressure protection time - third low-pressure warning time.

[0103] As one optional embodiment, the controller determines the opening adjustment rule of the electronic expansion valve based on the updated number of protection cycles, specifically including:

[0104] Determine whether the updated protection count has reached the preset protection count threshold;

[0105] If so, then the opening adjustment rule of the electronic expansion valve is determined to be increased to the maximum opening.

[0106] If not, then the opening adjustment rule of the electronic expansion valve is determined to be increased to the third preset opening.

[0107] Specifically, in conjunction with the above embodiments, when the controller determines the opening adjustment rule of the electronic expansion valve based on the updated protection count, it can further determine whether the updated protection count has reached the preset protection count threshold. If it is determined that the updated protection count has reached the preset protection count threshold, the opening adjustment rule of the electronic expansion valve is determined to be: increase the opening of the electronic expansion valve from the current opening to the maximum opening. If it is determined that the updated protection count has not reached the preset protection count threshold, the opening adjustment rule of the electronic expansion valve is determined to be: increase the opening of the electronic expansion valve from the current opening to the third preset opening.

[0108] It can be understood that, when corresponding processing is performed for the third time point, the current opening degree of the electronic expansion valve is the adjusted opening degree obtained after corresponding processing is performed for the second time point. If the opening degree adjustment rule of the electronic expansion valve determined at the second time point is that the opening degree of the electronic expansion valve is increased from the current opening degree to the second preset opening degree, the current opening degree of the electronic expansion valve corresponding to the third time point is the second preset opening degree. If the opening degree adjustment rule of the electronic expansion valve determined at the second time point is that the opening degree of the electronic expansion valve is controlled to remain unchanged at the current opening degree, the current opening degree of the electronic expansion valve corresponding to the third time point is the current opening degree of the electronic expansion valve corresponding to the second time point.

[0109] It should be noted that, in the embodiment of the application, the opening degree of the electronic expansion valve can be increased from the current opening degree to the third preset opening degree by increasing the third preset step number. For example, it is assumed that the current opening degree of the electronic expansion valve corresponding to the first time point is P0, the first preset step number is ΔP1, and the first preset opening degree is P1. Then, P1=P0+ΔP1. Further, it is assumed that the second preset step number is ΔP2 and the second preset opening degree is P2. Then, P2=P0+ΔP2 or P2=P1+ΔP2. Further, it is assumed that the third preset step number is ΔP3 and the third preset opening degree is P3. Then, P3=P0+ΔP3 or P3=P1+ΔP3 or P3=P2+ΔP3. Preferably, the value range of ΔP3 is 20 steps to 100 steps.

[0110] As one of the optional embodiments, the controller determines the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of the preset time points in turn, and the method further comprises the following steps of:

[0111] When the running time of the compressor reaches a preset fourth time point, it is judged whether the low-pressure pressure switch is in the off state. The fourth time point is equal to the low-pressure protection time minus a preset low-pressure change time.

[0112] If yes, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase to the maximum opening degree.

[0113] If no, it is determined that the opening degree adjustment rule of the electronic expansion valve is to remain unchanged at the current opening degree.

[0114] In combination with Figure 7 It is shown that the controller provided by the embodiment of the application is a working flowchart of a controller of an air conditioner, and based on the above-mentioned embodiments, when the controller executes Figure 3At step S13, after the corresponding processing for the third time point, it is determined whether the running time of the compressor reaches a fourth time point (S1341); if the running time of the compressor does not reach the fourth time point, the next determination is continued; if the running time of the compressor reaches the fourth time point, it is further determined whether the low-pressure pressure switch is in an open state (S1342); if the low-pressure pressure switch is in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase the opening degree of the electronic expansion valve from the current opening degree to the maximum opening degree (S1343); if the low-pressure pressure switch is not in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to control the opening degree of the electronic expansion valve to remain unchanged at the current opening degree (S1344). Figure 7 At step S13, after the corresponding processing for the third time point, it is determined whether the running time of the compressor reaches a fourth time point (S1341); if the running time of the compressor does not reach the fourth time point, the next determination is continued; if the running time of the compressor reaches the fourth time point, it is further determined whether the low-pressure pressure switch is in an open state (S1342); if the low-pressure pressure switch is in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase the opening degree of the electronic expansion valve from the current opening degree to the maximum opening degree (S1343); if the low-pressure pressure switch is not in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to control the opening degree of the electronic expansion valve to remain unchanged at the current opening degree (S1344). Figure 7 At step S13, after the corresponding processing for the third time point, it is determined whether the running time of the compressor reaches a fourth time point (S1341); if the running time of the compressor does not reach the fourth time point, the next determination is continued; if the running time of the compressor reaches the fourth time point, it is further determined whether the low-pressure pressure switch is in an open state (S1342); if the low-pressure pressure switch is in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase the opening degree of the electronic expansion valve from the current opening degree to the maximum opening degree (S1343); if the low-pressure pressure switch is not in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to control the opening degree of the electronic expansion valve to remain unchanged at the current opening degree (S1344). Figure 7 At step S13, after the corresponding processing for the third time point, it is determined whether the running time of the compressor reaches a fourth time point (S1341); if the running time of the compressor does not reach the fourth time point, the next determination is continued; if the running time of the compressor reaches the fourth time point, it is further determined whether the low-pressure pressure switch is in an open state (S1342); if the low-pressure pressure switch is in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase the opening degree of the electronic expansion valve from the current opening degree to the maximum opening degree (S1343); if the low-pressure pressure switch is not in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to control the opening degree of the electronic expansion valve to remain unchanged at the current opening degree (S1344). Figure 7 At step S13, after the corresponding processing for the third time point, it is determined whether the running time of the compressor reaches a fourth time point (S1341); if the running time of the compressor does not reach the fourth time point, the next determination is continued; if the running time of the compressor reaches the fourth time point, it is further determined whether the low-pressure pressure switch is in an open state (S1342); if the low-pressure pressure switch is in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase the opening degree of the electronic expansion valve from the current opening degree to the maximum opening degree (S1343); if the low-pressure pressure switch is not in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to control the opening degree of the electronic expansion valve to remain unchanged at the current opening degree (S1344).

[0115] At step S13, after the corresponding processing for the third time point, it is determined whether the running time of the compressor reaches a fourth time point (S1341); if the running time of the compressor does not reach the fourth time point, the next determination is continued; if the running time of the compressor reaches the fourth time point, it is further determined whether the low-pressure pressure switch is in an open state (S1342); if the low-pressure pressure switch is in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase the opening degree of the electronic expansion valve from the current opening degree to the maximum opening degree (S1343); if the low-pressure pressure switch is not in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to control the opening degree of the electronic expansion valve to remain unchanged at the current opening degree (S1344).

[0116] At step S13, after the corresponding processing for the third time point, it is determined whether the running time of the compressor reaches a fourth time point (S1341); if the running time of the compressor does not reach the fourth time point, the next determination is continued; if the running time of the compressor reaches the fourth time point, it is further determined whether the low-pressure pressure switch is in an open state (S1342); if the low-pressure pressure switch is in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase the opening degree of the electronic expansion valve from the current opening degree to the maximum opening degree (S1343); if the low-pressure pressure switch is not in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to control the opening degree of the electronic expansion valve to remain unchanged at the current opening degree (S1344).

[0117] At step S13, after the corresponding processing for the third time point, it is determined whether the running time of the compressor reaches a fourth time point (S1341); if the running time of the compressor does not reach the fourth time point, the next determination is continued; if the running time of the compressor reaches the fourth time point, it is further determined whether the low-pressure pressure switch is in an open state (S1342); if the low-pressure pressure switch is in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase the opening degree of the electronic expansion valve from the current opening degree to the maximum opening degree (S1343); if the low-pressure pressure switch is not in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to control the opening degree of the electronic expansion valve to remain unchanged at the current opening degree (S1344).

[0118] Specifically, in conjunction with the above embodiments, the preset first low-pressure warning time, second low-pressure warning time, and third low-pressure warning time satisfy the following condition: third low-pressure warning time < second low-pressure warning time < first low-pressure warning time, and the value range of the first low-pressure warning time, second low-pressure warning time, and third low-pressure warning time is 1 second to (low-pressure protection time - low-pressure change time) seconds.

[0119] As one optional embodiment, the air conditioner further includes:

[0120] A bypass circuit is provided between the outlet of the outdoor heat exchanger and the suction port of the compressor, and a solenoid valve is provided on the bypass circuit;

[0121] The controller determines the opening adjustment rule of the electronic expansion valve based on the on / off state of the low-pressure switch at each of a preset number of time points when the compressor's operating time sequentially reaches these points. Specifically, this includes:

[0122] When the compressor's operating time reaches the preset fourth time point, it is determined whether the low-pressure switch is in the open state; wherein, the fourth time point = the low-pressure protection time - the preset low-pressure change time;

[0123] If so, the opening adjustment rule of the electronic expansion valve is determined to be increased to the maximum opening, and the solenoid valve is controlled to change from the closed state to the open state;

[0124] If not, then the opening adjustment rule of the electronic expansion valve is determined to maintain the current opening.

[0125] See Figure 8 The diagram shown is a schematic diagram of the internal structure of an air conditioner provided in another embodiment of the present invention. In this embodiment, the air conditioner further includes a bypass circuit, which is located between the outlet of the outdoor heat exchanger 3 and the suction port of the compressor 1, and a solenoid valve 7 is provided on the bypass circuit.

[0126] It should be noted that, with Figure 2 similar, Figure 8 The solid arrows indicate the direction of refrigerant flow in the refrigeration cycle, while the dashed arrows indicate the direction of refrigerant flow in the heating cycle.

[0127] Combination Figure 9 The diagram shown is a flowchart of the operation of an air conditioner controller according to another embodiment of the present invention. Based on the above embodiments, in specific implementation of this embodiment, the controller executes... Figure 3 In step S13, after processing the third time point, it can be determined whether the compressor's running time has reached the preset fourth time point.Figure 9 If it is determined that the running time of the compressor has reached the fourth time point, it is further determined whether the low-pressure pressure switch is in an open state (step S1352 shown); if it is determined that the low-pressure pressure switch is in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to increase the opening degree of the electronic expansion valve from the current opening degree to the maximum opening degree, and the solenoid valve is controlled to switch from the closed state to the open state (step S1353 shown); if it is determined that the low-pressure pressure switch is not in the open state, it is determined that the opening degree adjustment rule of the electronic expansion valve is to control the opening degree of the electronic expansion valve to remain unchanged at the current opening degree (step S1354 shown). Figure 9 Figure 9 Figure 9

[0128] It should be noted that, in the case where the bypass circuit is set (as shown in FIG. 1), when the controller executes step S13 shown, the processing flow for the first time point, the second time point and the third time point is the same as that in the case where the bypass circuit is not set (as shown in FIG. 2), when the controller executes step S13 shown, the processing flow for the first time point, the second time point and the third time point is the same, which will not be described here. Figure 8 Figure 3 Figures 2 to 6 Figure 3

[0129] The air conditioner provided by the embodiment of the present application is provided with a bypass circuit, when the solenoid valve is switched from the closed state to the open state, the bypass circuit is communicated (i.e., the high-pressure side and the low-pressure side are directly communicated), so that the refrigerant can directly return to the suction port of the compressor from the outlet of the outdoor heat exchanger, the refrigerant flow of the low-pressure side can be quickly increased, so that the low-pressure side pressure rises relatively quickly, and the low-pressure fault can be effectively avoided; however, the processing mode of setting the bypass circuit needs to consider whether the air conditioner meets the installation space position requirement of the bypass circuit, and additionally increases the cost; the processing mode of not setting the bypass circuit in the above embodiment only needs to optimize the design of the opening degree control logic of the electronic expansion valve, without additional cost.

[0130] Referring to FIG. 3 shown, it is a working example flow chart of the controller of the air conditioner provided by an embodiment of the present application, in the case where the bypass circuit is not set, the overall working flow of the controller is as follows: Figure 10

[0131] ​​​​​​​​(1) setting a low pressure protection time Tb, a first low pressure early warning time At1, a second low pressure early warning time At2, a third low pressure early warning time At3 and a low pressure change time Tc; wherein At3 < At2 < At1, and the value range of At1, At2 and At3 is 1 second to (Tb-Tc) seconds;

[0132] (2) recording the running time t of the compressor after the air conditioner defrosting ends and turns into heating mode;

[0133] (3) judging whether t=Tb-At1 is met, if t=Tb-At1 is not met, then continuing to wait for the next judgment; if t=Tb-At1 is met, then detecting whether the low pressure protection condition of the low pressure switch is met; if the low pressure protection condition is not met, then the opening degree of the electronic expansion valve does not need to be adjusted, maintaining the current opening degree to continue running; if the low pressure protection condition is met, then recording the protection times LP=1 of the low pressure switch, and increasing the opening degree P of the electronic expansion valve to P=P1, and maintaining P1 opening degree to continue running;

[0134] (4) judging whether t=Tb-At2 is met, if t=Tb-At2 is not met, then continuing to wait for the next judgment; if t=Tb-At2 is met, then detecting whether the low pressure protection condition of the low pressure switch is met; if the low pressure protection condition is not met, then the opening degree of the electronic expansion valve does not need to be adjusted, maintaining the current opening degree to continue running; if the low pressure protection condition is met, then recording the protection times LP=1+1=2 of the low pressure switch, and increasing the opening degree P of the electronic expansion valve to P=P2, and maintaining P2 opening degree to continue running;

[0135] (5) judging whether t=Tb-At3 is met, if t=Tb-At3 is not met, then continuing to wait for the next judgment; if t=Tb-At3 is met, then detecting whether the low pressure protection condition of the low pressure switch is met; if the low pressure protection condition is not met, then the opening degree of the electronic expansion valve does not need to be adjusted, maintaining the current opening degree to continue running; if the low pressure protection condition is met, then recording the protection times LP=2+1=3 of the low pressure switch, and further judging whether LP≥3 is met; if LP≥3 is met, then increasing the opening degree P of the electronic expansion valve to P=Pmax, and maintaining Pmax opening degree to continue running; if LP≥3 is not met, then increasing the opening degree P of the electronic expansion valve to P=P3, and maintaining P3 opening degree to continue running;

[0136] (6) judging whether t=Tb-Tc is met, if t=Tb-Tc is not met, then continuing to wait for next time of judgment, if t=Tb-Tc is met, then detecting whether the low-pressure pressure switch meets the low-pressure protection condition, if the low-pressure protection condition is not met, then the opening degree of the electronic expansion valve does not need to be adjusted, maintaining the current opening degree to continue running, if the low-pressure protection condition is met, then increasing the opening degree P of the electronic expansion valve to P=Pmax, and maintaining the Pmax opening degree to continue running.

[0137] Referring to Figure 11 Fig. 4 is a working example flow chart of a controller of an air conditioner provided by another embodiment of the present application, and the overall working flow of the controller is as follows in combination with the above embodiment in the case of setting a bypass circuit:

[0138] (1) setting a low-pressure protection time Tb, a first low-pressure early warning time Δt1, a second low-pressure early warning time Δt2, a third low-pressure early warning time Δt3 and a low-pressure change time Tc, wherein Δt3<Δt2<Δt1, and the value range of Δt1, Δt2 and Δt3 is 1 second to (Tb-Tc) seconds;

[0139] (2) after the air conditioner defrosting ends and turns into a heating mode, recording the running time t of the compressor;

[0140] (3) judging whether t=Tb-Δt1 is met, if t=Tb-Δt1 is not met, then continuing to wait for next time of judgment, if t=Tb-Δt1 is met, then detecting whether the low-pressure pressure switch meets the low-pressure protection condition, if the low-pressure protection condition is not met, then the opening degree of the electronic expansion valve does not need to be adjusted, maintaining the current opening degree to continue running, if the low-pressure protection condition is met, then recording the protection times LP=1 of the low-pressure pressure switch, and increasing the opening degree P of the electronic expansion valve to P=P1, and maintaining the P1 opening degree to continue running;

[0141] (4) judging whether t=Tb-Δt2 is met, if t=Tb-Δt2 is not met, then continuing to wait for next time of judgment, if t=Tb-Δt2 is met, then detecting whether the low-pressure pressure switch meets the low-pressure protection condition, if the low-pressure protection condition is not met, then the opening degree of the electronic expansion valve does not need to be adjusted, maintaining the current opening degree to continue running, if the low-pressure protection condition is met, then recording the protection times LP=1+1=2 of the low-pressure pressure switch, and increasing the opening degree P of the electronic expansion valve to P=P2, and maintaining the P2 opening degree to continue running;

[0142] (5) judging whether t=Tb-△t3 is met, if t=Tb-△t3 is not met, continuing to wait for next time of judging, if t=Tb-△t3 is met, detecting whether the low-pressure pressure switch meets the low-pressure protection condition, if the low-pressure protection condition is not met, the opening degree of the electronic expansion valve does not need to be adjusted, keeping the current opening degree to continue running, if the low-pressure protection condition is met, recording the protection times of the low-pressure pressure switch LP=2+1=3, and further judging whether LP≥3 is met, if LP≥3 is met, increasing the opening degree P of the electronic expansion valve to P=Pmax, and keeping the Pmax opening degree to continue running, if LP≥3 is not met, increasing the opening degree P of the electronic expansion valve to P=P3, and keeping the P3 opening degree to continue running;

[0143] (6) judging whether t=Tb-Tc is met, if t=Tb-Tc is not met, continuing to wait for next time of judging, if t=Tb-Tc is met, detecting whether the low-pressure pressure switch meets the low-pressure protection condition, if the low-pressure protection condition is not met, the opening degree of the electronic expansion valve does not need to be adjusted, keeping the current opening degree to continue running, if the low-pressure protection condition is met, increasing the opening degree P of the electronic expansion valve to P=Pmax, and keeping the Pmax opening degree to continue running, and converting the electromagnetic valve from the closed state to the open state.

[0144] The embodiment of the present application also provides a control method of an air conditioner, which is suitable for the air conditioner of any one of the above-mentioned embodiments, and the air conditioner comprises:

[0145] a refrigerant circuit, which circulates refrigerant in a circuit composed of a compressor, a condenser, an electronic expansion valve and an evaporator, one of the condenser and the evaporator being an outdoor heat exchanger, and the other being an indoor heat exchanger;

[0146] a low-pressure pressure switch, which is used for low-pressure protection of the air conditioner;

[0147] The method is executed by the controller, and the method comprises:

[0148] after the air conditioner is switched into the heating mode from the defrosting, obtaining the running time of the compressor;

[0149] determining the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points in turn, wherein the plurality of time points are determined according to a preset low-pressure protection time;

[0150] adjusting the current opening degree of the electronic expansion valve according to the determined opening degree adjustment rule.

[0151] In some embodiments, the opening and closing state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points is used to determine the opening degree adjustment rule of the electronic expansion valve, specifically comprising:

[0152] When the running time of the compressor reaches a preset first time point, it is determined whether the low-pressure pressure switch is in an open state; wherein the first time point = the low-pressure protection time - a preset first low-pressure early warning time;

[0153] If yes, the protection times of the low-pressure pressure switch are recorded, and the opening degree adjustment rule of the electronic expansion valve is determined to be increased to a first preset opening degree;

[0154] If no, the opening degree adjustment rule of the electronic expansion valve is determined to be maintained at the current opening degree.

[0155] In some embodiments, the opening and closing state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points is used to determine the opening degree adjustment rule of the electronic expansion valve, further comprising:

[0156] When the running time of the compressor reaches a preset second time point, it is determined whether the low-pressure pressure switch is in an open state; wherein the second time point = the low-pressure protection time - a preset second low-pressure early warning time;

[0157] If yes, the protection times of the low-pressure pressure switch are updated, and the opening degree adjustment rule of the electronic expansion valve is determined to be increased to a second preset opening degree;

[0158] If no, the opening degree adjustment rule of the electronic expansion valve is determined to be maintained at the current opening degree.

[0159] In some embodiments, the opening and closing state of the low-pressure pressure switch when the running time of the compressor reaches each of a plurality of preset time points is used to determine the opening degree adjustment rule of the electronic expansion valve, further comprising:

[0160] When the running time of the compressor reaches a preset third time point, it is determined whether the low-pressure pressure switch is in an open state; wherein the third time point = the low-pressure protection time - a preset third low-pressure early warning time;

[0161] If yes, the protection times of the low-pressure pressure switch are updated, and the opening degree adjustment rule of the electronic expansion valve is determined according to the updated protection times;

[0162] If no, the opening degree adjustment rule of the electronic expansion valve is determined to be maintained at the current opening degree.

[0163] In some embodiments, the determining the opening degree adjustment rule of the electronic expansion valve according to the updated protection times specifically comprises:

[0164] determining whether the updated protection times reach a preset protection times threshold;

[0165] if yes, determining that the opening degree adjustment rule of the electronic expansion valve is to increase to the maximum opening degree;

[0166] if no, determining that the opening degree adjustment rule of the electronic expansion valve is to increase to the third preset opening degree.

[0167] In some embodiments, the determining the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of the preset time points in turn further comprises:

[0168] when the running time of the compressor reaches a preset fourth time point, determining whether the low-pressure pressure switch is in the open state; wherein the fourth time point = the low-pressure protection time - a preset low-pressure change time;

[0169] if yes, determining that the opening degree adjustment rule of the electronic expansion valve is to increase to the maximum opening degree;

[0170] if no, determining that the opening degree adjustment rule of the electronic expansion valve is to keep the current opening degree.

[0171] In some embodiments, 1 < the third low-pressure early warning time < the second low-pressure early warning time < the first low-pressure early warning time ≤ the low-pressure protection time - the low-pressure change time.

[0172] In some embodiments, the air conditioner further comprises:

[0173] a bypass circuit arranged between the outlet of the outdoor heat exchanger and the suction port of the compressor, and an electromagnetic valve arranged on the bypass circuit;

[0174] the determining the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-pressure pressure switch when the running time of the compressor reaches each of the preset time points in turn specifically comprises:

[0175] when the running time of the compressor reaches a preset fourth time point, determining whether the low-pressure pressure switch is in the open state; wherein the fourth time point = the low-pressure protection time - a preset low-pressure change time;

[0176] if yes, determining that the opening degree adjustment rule of the electronic expansion valve is to increase to the maximum opening degree, and controlling the electromagnetic valve to switch from the closed state to the open state;

[0177] If no, it is determined that the opening degree adjustment rule of the electronic expansion valve is to keep the current opening degree.

[0178] It should be noted that the control method of the air conditioner provided by the embodiment of the present application can realize all the working processes of the air conditioner described in any of the above embodiments, and the specific implementation schemes and technical effects achieved by the method correspond to the same as those of the air conditioner described in the above embodiments, which will not be repeated here.

[0179] In summary, the air conditioner and the control method of the air conditioner provided by the embodiment of the present application, the air conditioner comprises: a refrigerant circuit, which circulates refrigerant in a circuit composed of a compressor, a condenser, an electronic expansion valve and an evaporator, one of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger; a low-voltage pressure switch for low-voltage protection of the air conditioner; a controller for: after the air conditioner defrosting ends and turns into a heating mode, obtaining the running time of the compressor; determining the opening degree adjustment rule of the electronic expansion valve according to the on-off state of the low-voltage pressure switch when the running time of the compressor reaches each of a plurality of preset time points in turn, wherein the plurality of time points are determined according to a preset low-voltage protection time; and adjusting the current opening degree of the electronic expansion valve according to the determined opening degree adjustment rule. The embodiment of the present application can improve the refrigerant flow by setting the low-voltage protection time and adjusting the opening degree of the electronic expansion valve based on the plurality of time points set according to the low-voltage protection time after the air conditioner defrosting and heating, thereby avoiding low-voltage failure due to low pressure on the low-pressure side.

[0180] The above only describes some embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the technical principles of the present application, some improvements and modifications can be made, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. An air conditioner, characterized in that, include: The refrigerant circuit circulates the refrigerant in a loop consisting of a compressor, a condenser, an electronic expansion valve, and an evaporator. One of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger. A low-pressure switch is used for low-pressure protection of the air conditioner; Controller, used for: After the air conditioner finishes defrosting and switches to heating mode, the running time of the compressor is obtained; The opening adjustment rule of the electronic expansion valve is determined based on the on / off state of the low-pressure switch at each of a preset number of time points when the compressor's operating time sequentially reaches these points; wherein, the preset number of time points are determined based on a preset low-pressure protection time. The current opening of the electronic expansion valve is adjusted according to the determined opening adjustment rules.

2. The air conditioner as described in claim 1, characterized in that, The controller determines the opening adjustment rule of the electronic expansion valve based on the on / off state of the low-pressure switch at each of a preset number of time points when the compressor's operating time sequentially reaches these points. Specifically, this includes: When the compressor's operating time reaches a preset first time point, it is determined whether the low-pressure switch is in the off state; wherein, the first time point = the low-pressure protection time - the preset first low-pressure warning time; If so, record the number of times the low-pressure switch is activated, and determine that the opening adjustment rule of the electronic expansion valve is to increase to the first preset opening. If not, then the opening adjustment rule of the electronic expansion valve is determined to maintain the current opening.

3. The air conditioner as described in claim 2, characterized in that, The controller determines the opening adjustment rule of the electronic expansion valve based on the on / off state of the low-pressure switch at each of a preset number of time points when the compressor's operating time sequentially reaches these points. The controller also includes: When the compressor's operating time reaches a preset second time point, it is determined whether the low-pressure switch is in the off state; wherein, the second time point = the low-pressure protection time - the preset second low-pressure warning time; If so, update the protection count of the low-pressure switch and determine that the opening adjustment rule of the electronic expansion valve is to increase to the second preset opening. If not, then the opening adjustment rule of the electronic expansion valve is determined to maintain the current opening.

4. The air conditioner as described in claim 3, characterized in that, The controller determines the opening adjustment rule of the electronic expansion valve based on the on / off state of the low-pressure switch at each of a preset number of time points when the compressor's operating time sequentially reaches these points. The controller also includes: When the compressor's operating time reaches a preset third time point, it is determined whether the low-pressure switch is in the off state; wherein, the third time point = the low-pressure protection time - the preset third low-pressure warning time; If so, update the protection count of the low-pressure switch, and determine the opening adjustment rule of the electronic expansion valve based on the updated protection count; If not, then the opening adjustment rule of the electronic expansion valve is determined to maintain the current opening.

5. The air conditioner as described in claim 4, characterized in that, The controller determines the opening adjustment rule of the electronic expansion valve based on the updated number of protection cycles, specifically including: Determine whether the updated protection count has reached the preset protection count threshold; If so, then the opening adjustment rule of the electronic expansion valve is determined to be increased to the maximum opening. If not, then the opening adjustment rule of the electronic expansion valve is determined to be increased to the third preset opening.

6. The air conditioner as described in claim 4, characterized in that, The controller determines the opening adjustment rule of the electronic expansion valve based on the on / off state of the low-pressure switch at each of a preset number of time points when the compressor's operating time sequentially reaches these points. The controller also includes: When the compressor's operating time reaches the preset fourth time point, it is determined whether the low-pressure switch is in the open state; wherein, the fourth time point = the low-pressure protection time - the preset low-pressure change time; If so, then the opening adjustment rule of the electronic expansion valve is determined to be increased to the maximum opening. If not, then the opening adjustment rule of the electronic expansion valve is determined to maintain the current opening.

7. The air conditioner as described in claim 6, characterized in that, 1 ≤ the third low-pressure warning time < the second low-pressure warning time < the first low-pressure warning time ≤ the low-pressure protection time - the low-pressure change time.

8. The air conditioner as described in claim 1, characterized in that, The air conditioner also includes: A bypass circuit is provided between the outlet of the outdoor heat exchanger and the suction port of the compressor, and a solenoid valve is provided on the bypass circuit; The controller determines the opening adjustment rule of the electronic expansion valve based on the on / off state of the low-pressure switch at each of a preset number of time points when the compressor's operating time sequentially reaches these points. Specifically, this includes: When the compressor's operating time reaches the preset fourth time point, it is determined whether the low-pressure switch is in the open state; wherein, the fourth time point = the low-pressure protection time - the preset low-pressure change time; If so, the opening adjustment rule of the electronic expansion valve is determined to be to increase to the maximum opening, and the solenoid valve is controlled to change from the closed state to the open state; If not, then the opening adjustment rule of the electronic expansion valve is determined to maintain the current opening.

9. A control method for an air conditioner, characterized in that, The air conditioner includes: The refrigerant circuit circulates the refrigerant in a loop consisting of a compressor, a condenser, an electronic expansion valve, and an evaporator. One of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger. A low-pressure switch is used for low-pressure protection of the air conditioner; The method includes: After the air conditioner finishes defrosting and switches to heating mode, the running time of the compressor is obtained; The opening adjustment rule of the electronic expansion valve is determined based on the on / off state of the low-pressure switch at each of a preset number of time points when the compressor's operating time sequentially reaches these points; wherein, the preset number of time points are determined based on a preset low-pressure protection time. The current opening of the electronic expansion valve is adjusted according to the determined opening adjustment rules.

10. The control method for an air conditioner as described in claim 9, characterized in that, The air conditioner also includes: A bypass circuit is provided between the outlet of the outdoor heat exchanger and the suction port of the compressor, and a solenoid valve is provided on the bypass circuit; The step of determining the opening adjustment rule of the electronic expansion valve based on the on / off state of the low-pressure switch when the compressor's operating time sequentially reaches each of a preset number of time points specifically includes: When the compressor's operating time reaches the preset fourth time point, it is determined whether the low-pressure switch is in the open state; wherein, the fourth time point = the low-pressure protection time - the preset low-pressure change time; If so, the opening adjustment rule of the electronic expansion valve is determined to be to increase to the maximum opening, and the solenoid valve is controlled to change from the closed state to the open state; If not, then the opening adjustment rule of the electronic expansion valve is determined to maintain the current opening.

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