Air conditioner and operation control method of air conditioner

Abstract

The present invention discloses an air conditioner and an operation control method of the air conditioner, comprising a circulation system formed by a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger. In response to a defrosting instruction, the four-way valve is switched to make the reverse defrosting circuit conductive, and the air conditioner enters the defrosting mode; the current operating frequency of the compressor is adjusted to a preset defrosting frequency, and the current opening of the electronic expansion valve is adjusted to a preset maximum opening; the outdoor coil temperature is detected in real time, and if the outdoor coil temperature is greater than a first preset temperature, the current operating frequency of the compressor is adjusted to a preset drying frequency, and the current opening of the electronic expansion valve is reduced to the initial opening of the air conditioner heating mode; wherein the drying frequency is less than the defrosting frequency. The present invention can effectively prevent the abnormal blockage of the air conditioner system during the defrosting process, and improve the operation reliability of the air conditioner.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning systems, and in particular to an air conditioner and an operation control method of the air conditioner. Background Art

[0002] Air conditioners have become an indispensable smart device in people's daily lives, capable of achieving multiple functions such as cooling, heating and dehumidification. The defrosting problem of air source heat pump systems is a key technical issue for air conditioners, which has a significant impact on heating performance and comfort. When the outdoor ambient temperature is low, air conditioners are prone to frost, and performance decays rapidly, resulting in insufficient heating capacity. At present, air conditioners generally use conventional reverse cycle defrosting. This defrosting method does not increase the cost of the air conditioner and is the simplest to implement, so it is widely used.

[0003] However, in the process of implementing the present invention, the inventors found that the prior art has at least the following problems: when the air conditioner enters the reverse cycle defrosting mode, the lubricating oil precipitates during the gasification process of the refrigerant in the indoor unit of the air conditioner, and the evaporation temperature gradually decreases, causing the lubricating oil to form flocs and adhere to the inner wall of the heat exchange tube, resulting in the enrichment of the lubricating oil in the indoor heat exchanger; in addition, during the defrosting process, the refrigerant continuously migrates to the compressor, causing a large amount of lubricating oil to dissolve in the compressor oil pool. After the defrosting is completed, when the four-way valve is switched to the hot start stage, the refrigerant carries a lot of lubricating oil into the electronic expansion valve, and the low temperature causes the lubricating oil flocs to gather in the valve and the subsequent pipelines, and the refrigerant in the compressor cannot quickly participate in the system circulation, resulting in a low evaporation temperature on the low-pressure side after the throttling element, which is easy to cause oil blockage, resulting in the air conditioner being unable to operate normally. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide an air conditioner and an operation control method of the air conditioner, which can effectively prevent the abnormal blockage of the air conditioner system during the defrosting process and improve the operation reliability of the air conditioner.

[0005] To achieve the above object, an embodiment of the present invention provides an air conditioner, comprising:

[0006] A circulation system formed by a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger;

[0007] An outdoor temperature sensor, used to collect the outdoor coil temperature of the outdoor heat exchanger;

[0008] Controller for:

[0009] In response to a defrost command, the four-way valve is switched to conduct the reverse defrost circuit, and the air conditioner enters a defrost mode;

[0010] Adjusting the current operating frequency of the compressor to a preset defrosting frequency, and adjusting the current opening of the electronic expansion valve to a preset maximum opening;

[0011] Real-time detection of the outdoor coil temperature;

[0012] If the outdoor coil temperature is greater than a first preset temperature, the current operating frequency of the compressor is adjusted to a preset drying frequency, and the current opening of the electronic expansion valve is reduced to an initial opening of the air conditioner heating mode; wherein the drying frequency is less than the defrosting frequency.

[0013] As an improvement of the above solution, the air conditioner further comprises an indoor fan and an indoor temperature sensor, wherein the indoor temperature sensor is used to collect the indoor coil temperature of the indoor heat exchanger;

[0014] Then, after adjusting the current operating frequency of the compressor to the preset defrosting frequency and adjusting the current opening of the electronic expansion valve to the preset maximum opening, the controller is further used to:

[0015] Real-time detection of the indoor coil temperature;

[0016] If the indoor coil temperature is less than or equal to the second preset temperature, the indoor fan is controlled to start running.

[0017] As an improvement of the above solution, the controller is also used for:

[0018] When the air conditioner is defrosted, the compressor is kept running, and the four-way valve is switched to connect the heating circuit, and the air conditioner enters the heating mode start-up stage.

[0019] As an improvement of the above solution, the air conditioner further includes an outdoor fan; when the air conditioner is defrosted, the controller is further used to:

[0020] Adjust the current operating frequency of the compressor to a preset minimum frequency; control the electronic expansion valve to maintain the current opening; control the indoor fan to maintain the current operating state;

[0021] After the defrosting of the air conditioner is completed and delayed for a preset time, the outdoor fan is controlled to start running.

[0022] As an improvement of the above solution, after the air conditioner enters the start-up phase of the heating mode, the controller is further used to:

[0023] If the outdoor coil temperature is greater than or equal to a third preset temperature, adjusting the current opening of the electronic expansion valve to the initial opening of the air conditioner heating mode;

[0024] If the outdoor coil temperature is lower than the third preset temperature, the current opening of the electronic expansion valve is adjusted to the preset maximum opening and the opening is maintained until the start-up phase of the heating mode ends.

[0025] The embodiment of the present invention further provides an operation control method of an air conditioner, the air conditioner comprising:

[0026] A circulation system formed by a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger;

[0027] An outdoor temperature sensor, used to collect the outdoor coil temperature of the outdoor heat exchanger;

[0028] The method comprises:

[0029] In response to a defrost command, the four-way valve is switched to conduct the reverse defrost circuit, and the air conditioner enters a defrost mode;

[0030] Adjusting the current operating frequency of the compressor to a preset defrosting frequency, and adjusting the current opening of the electronic expansion valve to a preset maximum opening;

[0031] Real-time detection of the outdoor coil temperature;

[0032] If the outdoor coil temperature is greater than a first preset temperature, the current operating frequency of the compressor is adjusted to a preset drying frequency, and the current opening of the electronic expansion valve is reduced to an initial opening of the air conditioner heating mode; wherein the drying frequency is less than the defrosting frequency.

[0033] As an improvement of the above solution, the air conditioner further comprises an indoor fan and an indoor temperature sensor, wherein the indoor temperature sensor is used to collect the indoor coil temperature of the indoor heat exchanger;

[0034] After adjusting the current operating frequency of the compressor to the preset defrosting frequency and adjusting the current opening of the electronic expansion valve to the preset maximum opening, the method further includes:

[0035] Real-time detection of the indoor coil temperature;

[0036] If the indoor coil temperature is less than or equal to the second preset temperature, the indoor fan is controlled to start running.

[0037] As an improvement of the above solution, the method further includes:

[0038] When the air conditioner is defrosted, the compressor is kept running, and the four-way valve is switched to connect the heating circuit, and the air conditioner enters the heating mode start-up stage.

[0039] As an improvement of the above solution, the air conditioner further includes an outdoor fan;

[0040] When the air conditioner is defrosted, the method further includes:

[0041] Adjust the current operating frequency of the compressor to a preset minimum frequency; control the electronic expansion valve to maintain the current opening; control the indoor fan to maintain the current operating state;

[0042] After the defrosting of the air conditioner is completed and delayed for a preset time, the outdoor fan is controlled to start running.

[0043] As an improvement of the above solution, after the air conditioner enters the start-up phase of the heating mode, the method further includes:

[0044] If the outdoor coil temperature is greater than or equal to a third preset temperature, adjusting the current opening of the electronic expansion valve to the initial opening of the air conditioner heating mode;

[0045] If the outdoor coil temperature is lower than the third preset temperature, the current opening of the electronic expansion valve is adjusted to the preset maximum opening and the opening is maintained until the start-up phase of the heating mode ends.

[0046] Compared with the prior art, the air conditioner and the operation control method of the air conditioner disclosed in the present invention, in response to the defrost instruction, switch the four-way valve to make the reverse defrost circuit conductive, and the air conditioner enters the defrost mode. In the defrosting stage, the current operating frequency of the compressor is adjusted to the preset defrosting frequency, and the current opening of the electronic expansion valve is adjusted to the preset maximum opening. When it is detected that the outdoor coil temperature is greater than the first preset temperature, it is determined to enter the dehydration and drying stage, and the current operating frequency of the compressor is reduced to the preset drying frequency, and the current opening of the electronic expansion valve is reduced to the initial opening of the air conditioner heating mode, which can effectively alleviate the continued migration of the refrigerant to the compressor and the migration of the lubricating oil to the indoor unit, prevent the compressor oil pool from dissolving a large amount of refrigerant, and then prevent the refrigerant with a high oil content rate from passing through the throttling device in the heating startup stage after the defrosting is completed and the heating mode is switched, causing oil blockage. The embodiment of the present invention solves the problem of abnormal blockage of the throttling element in the existing defrosting process and the initial heating stage, and effectively enhances the stability and reliability of the air conditioner system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a structural schematic diagram of an air conditioner provided by an embodiment of the present invention;

[0048] Figure 2 is a schematic structural diagram of a circulation system of an air conditioner in an embodiment of the present invention;

[0049] Figure 3 is a schematic diagram of a preferred structure of a circulation system of an air conditioner in an embodiment of the present invention;

[0050] Figure 4 is a schematic flow chart of the work performed by the controller in the embodiment of the present invention under the first preferred implementation mode;

[0051] Figure 5 is a schematic flow chart of the work performed by the controller in the embodiment of the present invention under the second preferred implementation mode;

[0052] Figure 6 is a schematic flow chart of the work performed by the controller in the third preferred implementation mode in the embodiment of the present invention;

[0053] Figure 7 is a schematic flow chart of the work performed by the controller in the fourth preferred implementation mode of the embodiment of the present invention;

[0054] Figure 8 is a flowchart of the work performed by the controller in the fifth preferred implementation mode in the embodiment of the present invention

[0055] Fig. 9 It is a schematic diagram of the state timing of various components of the air conditioner in the prior art;

[0056] Fig.10 is a schematic diagram of the timing sequence of states of various components of an air conditioner according to an embodiment of the present invention;

[0057] Fig.11 It is a flow chart of an operation control method of an air conditioner provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] See also Figure 1 , is a schematic diagram of the structure of an air conditioner provided by an embodiment of the present invention. The embodiment of the present invention provides an air conditioner 10, the air conditioner 10 includes a circulation system 20, and the circulation system 20 includes a compressor 21, a four-way valve 22, an indoor heat exchanger 23, an electronic expansion valve 24 and an outdoor heat exchanger 25, which are cyclically connected to form.

[0060] Preferably, the air conditioner 10 further includes an indoor fan 30 and an outdoor fan 40 for performing corresponding air supply operations.

[0061] Specifically, see Figure 2 , is a structural diagram of the circulation system of the air conditioner in the embodiment of the present invention. The four-way valve 22 includes four interfaces A, B, C and D. By controlling the connectivity of different interfaces of the four-way valve, the on-off control of the heating circuit and the reverse defrosting circuit of the air conditioner is realized.

[0062] In the first case, when port A is connected to port B, and port C is connected to port D, the exhaust port of the compressor 21 is connected to the inlet of the indoor heat exchanger 23 through the four-way valve 22, the outlet of the indoor heat exchanger 23 is connected to the inlet of the electronic expansion valve 24, the outlet of the electronic expansion valve 24 is connected to the inlet of the outdoor heat exchanger 25, and the outlet of the outdoor heat exchanger 25 is connected to the return air port of the compressor 21 through the four-way valve 22, thereby forming a conductive heating circuit. In the heating mode of the air conditioner, the exhaust gas of the compressor 21 enters the indoor heat exchanger 23 through the four-way valve 22, and the refrigerant condenses into a supercooled liquid in the indoor heat exchanger 23. After being throttled by the electronic expansion valve 24, the refrigerant enters the outdoor heat exchanger 25, and the refrigerant enters the compressor 21 for inhalation after being evaporated into gas through heat exchange, completing the entire cycle.

[0063] In the second case, when port A is connected to port D, and port B is connected to port C, the exhaust port of the compressor 21 is connected to the inlet of the outdoor heat exchanger 25 through the four-way valve 22, the outlet of the outdoor heat exchanger 25 is connected to the inlet of the electronic expansion valve 24, the outlet of the electronic expansion valve 24 is connected to the inlet of the indoor heat exchanger 23, and the outlet of the outdoor heat exchanger 25 is connected to the return air port of the compressor 21 through the four-way valve 22, thereby forming a conductive reverse defrosting circuit. During the defrosting process, the air conditioner enters the cooling mode, and the high-temperature and high-pressure refrigerant output by the compressor 21 enters the outdoor heat exchanger 25 through the four-way valve 22. The refrigerant releases heat in the outdoor heat exchanger 25 to perform a defrosting operation, and the refrigerant after releasing heat passes through the electronic expansion valve 24 and the indoor heat exchanger 23 and returns to the compressor 21.

[0064] It should be noted that when the four-way valve 22 is in the power-on state, port A is connected to port B, and port C is connected to port D; when the four-way valve 22 is in the power-off state, port A is connected to port D, and port B is connected to port C. The specific structure and principle of the four-way valve 22 can refer to the existing technology and will not be elaborated here.

[0065] Preferably, see Figure 3 , is a schematic diagram of a preferred structure of the circulation system of the air conditioner in an embodiment of the present invention, wherein the circulation system 20 further includes a first filter 26 and a second filter 27, which are respectively arranged between the indoor heat exchanger 23 and the electronic expansion valve 24, and between the outdoor heat exchanger 25 and the electronic expansion valve 24.

[0066] Further, see Figure 1 and Figure 2 The air conditioner 10 further includes an indoor temperature sensor 50 and an outdoor temperature sensor 60. The indoor temperature sensor 50 is disposed on the coil surface of the indoor heat exchanger 23 and is used to collect the indoor coil temperature T of the indoor heat exchanger 23. in The outdoor temperature sensor 60 is disposed on the coil surface of the outdoor heat exchanger 25 and is used to collect the outdoor coil temperature T of the outdoor heat exchanger 25.out .

[0067] See also Figure 1 The air conditioner 10 further includes a controller 70, which is connected to each component in the circulation system 20, and is also connected to the indoor fan 30, the indoor temperature sensor 50 and the outdoor temperature sensor 60, so as to obtain and analyze various information and issue relevant control instructions.

[0068] Specifically, see Figure 4 , is a schematic flow chart of the work performed by the controller in the first preferred implementation mode in the embodiment of the present invention, and the controller 70 is used to perform steps S11 to S14:

[0069] S11, in response to a defrost instruction, switching the four-way valve to connect the reverse defrost circuit, and the air conditioner enters a defrost mode;

[0070] S12, adjusting the current operating frequency of the compressor to a preset defrosting frequency, and adjusting the current opening of the electronic expansion valve to a preset maximum opening;

[0071] S13, detecting the outdoor coil temperature in real time;

[0072] S14. If the outdoor coil temperature is greater than a first preset temperature, adjust the current operating frequency of the compressor to a preset drying frequency, and reduce the current opening of the electronic expansion valve to an initial opening of the air conditioner heating mode; wherein the drying frequency is less than the defrosting frequency.

[0073] The embodiment of the present invention is applied to the operation process of the air conditioner in the heating mode. When the outdoor ambient temperature is lower than a certain temperature, for example, 5°C, the air conditioner is frosted and the defrosting function of the air conditioner is started. In response to the defrosting instruction, the controller 70 controls the four-way valve 22 to be in the power-off state, so that the A port is connected to the D port, the B port is connected to the C port, the reverse defrosting circuit is turned on, and the air conditioner enters the defrosting mode.

[0074] The embodiment of the present invention divides the defrosting process into a defrosting stage and a drying stage. When the air conditioner enters the defrosting mode, it is first in the defrosting stage, and the controller 70 controls the compressor 21 to adjust the current operating frequency F to the preset defrosting frequency F. d , and adjust the current opening U of the electronic expansion valve 24 to the preset maximum opening U max That is, the electronic expansion valve is fully open and the throttling and pressure reduction function is closed. The refrigerant maintains its original state when flowing through the electronic expansion valve 24 without throttling and reducing the pressure. Therefore, when passing through the indoor heat exchanger 23, it will not absorb indoor heat from the indoor heat exchanger 23, reducing the impact on the indoor temperature.

[0075] It should be noted that the defrosting frequency F d and the maximum opening Umax It is preset, and its specific value can be set according to the actual application situation, and is not specifically limited here.

[0076] It should be noted that when it is determined that the air conditioner meets the defrost conditions, the indoor fan 30, the outdoor fan 40 and the compressor 21 are all in a stopped state. When the four-way valve is switched and the air conditioner enters the defrost mode, the compressor 21 restarts during the defrost stage, while the indoor fan 30 and the outdoor fan 40 remain in a stopped state, waiting for subsequent control instructions.

[0077] Furthermore, the controller 70 obtains the outdoor coil temperature T collected by the outdoor temperature sensor 60 in real time. out , according to the outdoor coil temperature T out To determine whether the air conditioner has finished defrosting and entered the drying stage, and to adjust the operating parameters of the compressor 21 and the electronic expansion valve 24 in the drying stage.

[0078] Specifically, the first preset temperature T is preset out_set , which is used to characterize the outdoor coil temperature when the frost layer of the outdoor unit melts. out , if T out >T out_set , indicating that the frost layer has been effectively melted, and the outdoor heat exchanger enters the dehydration and drying stage. At this time, the current operating frequency of the compressor 21 is gradually reduced to the preset drying frequency F h , and the current opening of the electronic expansion valve 24 is reduced to the initial opening U of the heating mode. on When the defrost enters the drying stage, reducing the operating frequency of the compressor and the opening of the electronic expansion valve can effectively prevent the refrigerant from migrating to the compressor and the lubricating oil from migrating to the indoor unit, and prevent a large amount of refrigerant from dissolving in the compressor oil pool.

[0079] Optionally, the first preset temperature T out_set The value range of can be set to 1 ~ 3 ° C, and its value can be set according to actual conditions and is not specifically limited here.

[0080] It should be noted that the drying frequency F h is pre-set and satisfies F h <F d , drying frequency F h The specific value of can be set according to the actual application situation and is not specifically limited here.

[0081] The embodiment of the present invention provides an air conditioner, which responds to the defrost instruction, switches the four-way valve to make the reverse defrost circuit conductive, and the air conditioner enters the defrost mode. In the defrost stage, the current operating frequency of the compressor is adjusted to the preset defrost frequency, and the current opening of the electronic expansion valve is adjusted to the preset maximum opening. When it is detected that the outdoor coil temperature is greater than the first preset temperature, it is determined to enter the dehydration and drying stage, and the current operating frequency of the compressor is reduced to the preset drying frequency, and the current opening of the electronic expansion valve is reduced to the initial opening of the air conditioner heating mode, which can effectively alleviate the continued migration of refrigerant to the compressor and the migration of lubricating oil to the indoor unit, prevent the compressor oil pool from dissolving a large amount of refrigerant, and then prevent the refrigerant with a high oil content rate from passing through the throttling device in the heating startup stage after the defrosting is completed and the heating mode is switched. The embodiment of the present invention solves the problem of abnormal blockage of the throttling element in the existing defrosting process and the initial heating stage, and effectively enhances the stability and reliability of the air conditioner system operation.

[0082] As a preferred embodiment, see Figure 5 , is a schematic flow chart of the work performed by the controller in the second preferred implementation manner in an embodiment of the present invention.

[0083] After adjusting the current operating frequency of the compressor to the preset defrosting frequency and adjusting the current opening of the electronic expansion valve to the preset maximum opening, the controller is further configured to perform steps S15 and S16:

[0084] S15, real-time detection of the indoor coil temperature;

[0085] S16: If the indoor coil temperature is less than or equal to a second preset temperature, control the indoor fan to start running.

[0086] After the air conditioner enters the defrost mode, adjusts the current operating frequency of the compressor to the preset defrost frequency, and adjusts the current opening of the electronic expansion valve to the preset maximum opening, the controller 70 also obtains the indoor coil temperature T collected by the indoor temperature sensor 50 in real time. in , according to the indoor coil temperature T in Controls the opening status of the indoor fan.

[0087] Specifically, the second preset temperature T is preset in_set , used to indicate whether the current indoor coil temperature is in a low temperature state. in , if T in ≤T in_set , controlling the indoor fan 30 to start running. Preferably, the controlling the indoor fan to start running is specifically: controlling the indoor fan to turn on the breeze mode.

[0088] It can be understood that if the air conditioner is in defrost mode, the indoor coil temperature always meets T in >T in_set , the indoor fan 30 remains in the stopped state.

[0089] It should be noted that the second preset temperature T in_set It can be set according to actual conditions and is not specifically limited here.

[0090] By adopting the technical means of the embodiments of the present invention, when it is detected that the indoor coil temperature is low, the indoor fan is controlled to start running, which can effectively alleviate the accumulation of lubricating oil in the indoor heat exchanger caused by further reduction of the indoor coil temperature, prevent and alleviate the occurrence of oil blockage, and cooperate with the subsequent judgment of whether to enter the drying stage according to the outdoor coil temperature, as well as the control of the compressor and the electronic expansion valve in the drying stage, to more effectively prevent the occurrence of oil blockage.

[0091] As a preferred embodiment, see Figure 6 , is a flow chart of the work performed by the controller in the third preferred implementation mode in the embodiment of the present invention. The embodiment of the present invention is further implemented on the basis of the previous embodiment. After steps S11 to S16, the controller 70 is further used to perform step S21:

[0092] S21. When the defrosting of the air conditioner is finished, the compressor is kept running, and the four-way valve is switched to make the heating circuit conductive, and the air conditioner enters the heating mode startup stage.

[0093] In the embodiment of the present invention, after the air conditioner enters the defrost mode, it is judged in real time whether the air conditioner meets the defrost end conditions. When the defrost of the air conditioner is finished, the four-way valve 22 is directly switched, and the four-way valve 22 is controlled to be in an energized state, so that ports A and B are connected, ports C and D are connected, and the heating circuit is turned on, and the air conditioner enters the startup phase of the heating mode. During this process, the compressor 21 remains in an on-state.

[0094] By adopting the technical means of the embodiment of the present invention, the compressor does not stop after defrosting is completed, and the four-way valve is directly switched. Compared with the prior art that controls the compressor to stop after the air conditioner defrosts and then switches the four-way valve, the high-temperature and high-pressure refrigerant remaining in the outdoor heat exchanger can be effectively introduced into the compressor suction, accelerating the boiling and precipitation of the refrigerant in the liquid mixture in the compressor oil pool, increasing the compressor suction volume, prompting the refrigerant to quickly participate in the system circulation, and preventing the low-pressure side temperature from being too low to provide temperature conditions for oil blockage.

[0095] In an optional implementation, the outdoor coil set temperature T is preset when the defrosting end condition is met. out_set ', real-time detection of the current outdoor coil temperature T outWhether T is satisfied out ≥T out_set ', if yes, it indicates that the defrosting end condition is met. Of course, other methods in the prior art can also be used to determine whether the defrosting is ended, which will not affect the beneficial effects of the present invention.

[0096] As a preferred embodiment, see Figure 7 , is a flowchart of the work performed by the controller in the fourth preferred implementation mode in the embodiment of the present invention. When the air conditioner is defrosted, the controller is further used to perform steps S22 and S23:

[0097] S22, adjusting the current operating frequency of the compressor to a preset minimum frequency; controlling the electronic expansion valve to maintain a current opening; and controlling the indoor fan to maintain a current operating state.

[0098] S23, after the defrosting of the air conditioner is completed and delayed for a preset time, controlling the outdoor fan to start running.

[0099] In the embodiment of the present invention, when the air conditioner is defrosted, the air conditioner switches back to the heating mode. During the switching process, the controller 70 keeps the compressor running, but adjusts the current operating frequency of the compressor to the preset minimum frequency F. min , while the electronic expansion valve 24 and the indoor fan 30 remain in the current state. The outdoor fan 40 starts to run after a delay of a preset time t.

[0100] It should be noted that the minimum frequency F of the compressor min It is preset, and its value can be set according to the actual application of the compressor, and is not specifically limited here. It can be understood that F min <F h <F d .

[0101] Optionally, the preset time length t is set to 10s. Of course, the preset time length t can also be set to other values ​​according to actual conditions, which is not specifically limited here.

[0102] By adopting the technical means of the embodiment of the present invention, after the air conditioner defrosts, the compressor is controlled not to stop, and the operating frequency is adjusted to the lowest frequency, which can ensure the stable switching of the four-way valve, and can introduce the high-temperature and high-pressure refrigerant remaining in the outdoor heat exchanger into the compressor suction, accelerate the boiling and precipitation of the refrigerant in the liquid mixture in the compressor oil pool, and promote the refrigerant to quickly participate in the system circulation, preventing the low-pressure side temperature from being too low and causing oil blockage. In addition, both the indoor fan and the outdoor fan are in the starting state to ensure the normal switching of the heating mode.

[0103] As a preferred embodiment, see Figure 8, is a flowchart of the work performed by the controller in the fifth preferred implementation mode in the embodiment of the present invention. Based on the above embodiment, after the air conditioner enters the heating mode startup phase, the controller is further used to perform steps S31 and S32:

[0104] S31, if the outdoor coil temperature is greater than or equal to a third preset temperature, adjusting the current opening of the electronic expansion valve to the initial opening of the air conditioner heating mode;

[0105] S32: If the outdoor coil temperature is lower than the third preset temperature, adjust the current opening of the electronic expansion valve to the preset maximum opening, and continue until the start-up phase of the heating mode ends.

[0106] In the embodiment of the present invention, after the air conditioner switches back to the heating mode, it is first in the heating mode startup phase, at which time the compressor 21 is adjusted to the preset heating mode startup frequency F. on , and the current opening of the electronic expansion valve 24 is the preset initial opening U on .

[0107] Preset the third preset temperature T out_on , used to characterize the lower limit setting temperature of the outdoor coil during the start-up phase of the air conditioner heating mode. Real-time judgment of the outdoor coil temperature T out The third preset temperature T out_on The size relationship is, when T out ≥T out_on , the current opening of the electronic expansion valve 24 always maintains the initial opening U on , and when T out <T out_on When the current opening of the electronic expansion valve 24 is adjusted to the initial maximum opening U max , and maintain maximum opening during the entire heating mode startup phase.

[0108] Optionally, the first preset temperature T out_on The value range can be set to -30 ~ 35 ° C, and its value can be set according to actual conditions and is not specifically limited here.

[0109] Preferably, step S32 is specifically as follows: if the outdoor coil temperature is lower than the third preset temperature and lasts for a certain period of time t on , adjusting the current opening of the electronic expansion valve to the preset maximum opening, and continuing until the start-up phase of the heating mode ends.

[0110] See also Fig. 9 and Fig.10 , Fig. 9 It is a schematic diagram of the state timing of each component of the air conditioner in the prior art. Fig.10It is a state timing diagram of various components of the air conditioner embodiment of the present invention. Compared with the defrost control strategy of the prior art, the defrost process of the present invention is divided into a defrosting stage and a drying stage. During the defrosting process, when it is detected that the indoor coil temperature is less than or equal to the second preset temperature, the indoor fan is controlled to start running, which can effectively alleviate the accumulation of lubricating oil in the indoor heat exchanger caused by further reduction of the indoor coil temperature, thereby preventing and alleviating the occurrence of oil blockage. When it is detected that the temperature of the outdoor coil is greater than the first preset temperature, it is determined to enter the dehydration and drying stage, and the current operating frequency of the compressor is reduced to the preset drying frequency, and the current opening of the electronic expansion valve is reduced to the initial opening of the air conditioner heating mode, which can effectively alleviate the continued migration of the refrigerant to the compressor and the migration of the lubricating oil to the indoor unit, prevent the compressor oil pool from dissolving a large amount of refrigerant, and then prevent the refrigerant with a high oil content from passing through the throttling device in the heating startup stage after the defrosting is completed and the heating mode is switched, causing oil blockage. In addition, at the end of the defrosting, the process of switching to the heating mode adopts a switching method without stopping the compressor, which can effectively introduce the residual high-temperature and high-pressure refrigerant in the outdoor heat exchanger into the compressor suction, accelerate the boiling and precipitation of the refrigerant in the liquid mixture in the compressor oil pool, increase the compressor suction volume, prompt the refrigerant to quickly participate in the system circulation, and prevent the low-pressure side temperature from being too low to provide temperature conditions for the occurrence of oil blockage. The embodiment of the present invention solves the problem of abnormal blockage of the throttling element in the existing defrosting process and the initial stage of heating, and effectively enhances the stability and reliability of the air conditioner system operation.

[0111] See also Fig.11 , is a flow chart of an operation control method of an air conditioner provided by an embodiment of the present invention. An operation control method of an air conditioner is provided by an embodiment of the present invention, and the air conditioner comprises:

[0112] A circulation system formed by a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger;

[0113] An outdoor temperature sensor, used to collect the outdoor coil temperature of the outdoor heat exchanger;

[0114] The method comprises:

[0115] In response to a defrost command, the four-way valve is switched to conduct the reverse defrost circuit, and the air conditioner enters a defrost mode;

[0116] Adjusting the current operating frequency of the compressor to a preset defrosting frequency, and adjusting the current opening of the electronic expansion valve to a preset maximum opening;

[0117] Real-time detection of the outdoor coil temperature;

[0118] If the outdoor coil temperature is greater than a first preset temperature, the current operating frequency of the compressor is adjusted to a preset drying frequency, and the current opening of the electronic expansion valve is reduced to an initial opening of the air conditioner heating mode; wherein the drying frequency is less than the defrosting frequency.

[0119] As a preferred embodiment, the air conditioner further comprises an indoor fan and an indoor temperature sensor, wherein the indoor temperature sensor is used to collect the indoor coil temperature of the indoor heat exchanger;

[0120] After adjusting the current operating frequency of the compressor to the preset defrosting frequency and adjusting the current opening of the electronic expansion valve to the preset maximum opening, the method further includes:

[0121] Real-time detection of the indoor coil temperature;

[0122] If the indoor coil temperature is less than or equal to the second preset temperature, the indoor fan is controlled to start running.

[0123] As a preferred embodiment, the method further comprises:

[0124] When the air conditioner is defrosted, the compressor is kept running, and the four-way valve is switched to connect the heating circuit, and the air conditioner enters the heating mode start-up stage.

[0125] As a preferred embodiment, the air conditioner further includes an outdoor fan;

[0126] When the air conditioner is defrosted, the method further includes:

[0127] Adjust the current operating frequency of the compressor to a preset minimum frequency; control the electronic expansion valve to maintain the current opening; control the indoor fan to maintain the current operating state;

[0128] After the defrosting of the air conditioner is completed and delayed for a preset time, the outdoor fan is controlled to start running.

[0129] As a preferred implementation, after the air conditioner enters the heating mode startup phase, the method further includes:

[0130] If the outdoor coil temperature is greater than or equal to a third preset temperature, adjusting the current opening of the electronic expansion valve to the initial opening of the air conditioner heating mode;

[0131] If the outdoor coil temperature is lower than the third preset temperature, the current opening of the electronic expansion valve is adjusted to the preset maximum opening and the opening is maintained until the start-up phase of the heating mode ends.

[0132] The technical means adopted in the embodiments of the present invention can effectively alleviate the accumulation of lubricating oil in the indoor heat exchanger caused by further reduction in indoor coil temperature, prevent and alleviate the occurrence of oil blockage, and effectively alleviate the continued migration of refrigerant to the compressor and the migration of lubricating oil to the indoor unit, prevent the compressor oil pool from dissolving a large amount of refrigerant, and further prevent the refrigerant with a high oil content from passing through the throttling device in the heating startup stage after switching to the heating mode after the defrosting is completed, causing oil blockage. The embodiments of the present invention solve the problem of abnormal blockage of throttling elements in the existing defrosting process and the initial stage of heating, and effectively enhance the stability and reliability of the air-conditioning system operation.

[0133] It should be noted that the operation control method of an air conditioner provided in an embodiment of the present invention is identical to all process steps executed by a controller of an air conditioner in the above embodiment, and the working principles and beneficial effects of the two correspond one to one, so they will not be described in detail.

[0134] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0135] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An air conditioner, characterized in that: include: A circulation system formed by a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger; An outdoor temperature sensor, used to collect the outdoor coil temperature of the outdoor heat exchanger; Controller for: In response to a defrost command, the four-way valve is switched to conduct the reverse defrost circuit, and the air conditioner enters a defrost mode; Adjusting the current operating frequency of the compressor to a preset defrosting frequency, and adjusting the current opening of the electronic expansion valve to a preset maximum opening; Real-time detection of the outdoor coil temperature; If the outdoor coil temperature is greater than a first preset temperature, the current operating frequency of the compressor is adjusted to a preset drying frequency, and the current opening of the electronic expansion valve is reduced to an initial opening of the air conditioner heating mode; wherein the drying frequency is less than the defrosting frequency; The controller is also used for: When the air conditioner is defrosted, the compressor is kept running, and the four-way valve is switched to conduct the heating circuit, and the air conditioner enters the heating mode start-up stage; After the air conditioner enters the start-up phase of the heating mode, the controller is further used for: If the outdoor coil temperature is greater than or equal to a third preset temperature, adjusting the current opening of the electronic expansion valve to the initial opening of the air conditioner heating mode; If the outdoor coil temperature is lower than the third preset temperature, the current opening of the electronic expansion valve is adjusted to the preset maximum opening and the opening is maintained until the start-up phase of the heating mode ends.

2. The air conditioner according to claim 1, characterized in that: The air conditioner further comprises an indoor fan and an indoor temperature sensor, wherein the indoor temperature sensor is used to collect the indoor coil temperature of the indoor heat exchanger; Then, after adjusting the current operating frequency of the compressor to the preset defrosting frequency and adjusting the current opening of the electronic expansion valve to the preset maximum opening, the controller is further used to: Real-time detection of the indoor coil temperature; If the indoor coil temperature is less than or equal to the second preset temperature, the indoor fan is controlled to start running.

3. The air conditioner according to claim 2, characterized in that: The air conditioner further comprises an outdoor fan; when the air conditioner is defrosted, the controller is further used to: Adjust the current operating frequency of the compressor to a preset minimum frequency; control the electronic expansion valve to maintain the current opening; control the indoor fan to maintain the current operating state; After the defrosting of the air conditioner is completed and delayed for a preset time, the outdoor fan is controlled to start running.

4. An operation control method of an air conditioner, characterized in that: The air conditioner comprises: A circulation system formed by a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger; An outdoor temperature sensor, used to collect the outdoor coil temperature of the outdoor heat exchanger; The method comprises: In response to a defrost command, the four-way valve is switched to conduct the reverse defrost circuit, and the air conditioner enters a defrost mode; Adjusting the current operating frequency of the compressor to a preset defrosting frequency, and adjusting the current opening of the electronic expansion valve to a preset maximum opening; Real-time detection of the outdoor coil temperature; If the outdoor coil temperature is greater than a first preset temperature, the current operating frequency of the compressor is adjusted to a preset drying frequency, and the current opening of the electronic expansion valve is reduced to an initial opening of the air conditioner heating mode; wherein the drying frequency is less than the defrosting frequency; The method further comprises: When the air conditioner is defrosted, the compressor is kept running, and the four-way valve is switched to conduct the heating circuit, and the air conditioner enters the heating mode start-up stage; After the air conditioner enters the heating mode startup phase, the method further includes: If the outdoor coil temperature is greater than or equal to a third preset temperature, adjusting the current opening of the electronic expansion valve to the initial opening of the air conditioner heating mode; If the outdoor coil temperature is lower than the third preset temperature, the current opening of the electronic expansion valve is adjusted to the preset maximum opening and the opening is maintained until the start-up phase of the heating mode ends.

5. The operation control method of the air conditioner according to claim 4, characterized in that: The air conditioner further comprises an indoor fan and an indoor temperature sensor, wherein the indoor temperature sensor is used to collect the indoor coil temperature of the indoor heat exchanger; After adjusting the current operating frequency of the compressor to the preset defrosting frequency and adjusting the current opening of the electronic expansion valve to the preset maximum opening, the method further includes: Real-time detection of the indoor coil temperature; If the indoor coil temperature is less than or equal to the second preset temperature, the indoor fan is controlled to start running.

6. The operation control method of the air conditioner according to claim 5, characterized in that: The air conditioner also includes an outdoor fan; When the air conditioner is defrosted, the method further includes: Adjust the current operating frequency of the compressor to a preset minimum frequency; control the electronic expansion valve to maintain the current opening; control the indoor fan to maintain the current operating state; After the defrosting of the air conditioner is completed and delayed for a preset time, the outdoor fan is controlled to start running.

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