Air conditioner and oil blockage detection method for air conditioner

Abstract

The present invention discloses an air conditioner and an oil blockage detection method for the air conditioner. The air conditioner includes 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 heating instruction, the four-way valve is switched to make the heating circuit conductive, and the air conditioner enters the heating mode startup phase; when the current operating frequency of the compressor is the preset startup frequency, the average operating power of the compressor in the preset time period before the current moment is calculated in real time as the average startup power; if the current average startup power drops more than the average startup power in the previous heating mode startup phase by more than a first preset drop threshold, it is determined that the circulation system is oil blocked in the heating phase. The present invention can effectively detect whether the air conditioner system is abnormally blocked, which is conducive to taking relevant protective measures in time when the blockage is detected, thereby improving the operational reliability of the air conditioner.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and in particular to an air conditioner and an oil blockage detection method for 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 defrost mode, 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. The low temperature causes the lubricating oil flocs to accumulate in the valve and the filter, thereby causing oil blockage, resulting in the air conditioner being unable to operate normally. Therefore, how to detect whether oil blockage occurs and perform relevant protective measures when oil blockage occurs is crucial to ensuring the normal operation of the air conditioner. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide an air conditioner and an oil blockage detection method for the air conditioner, which can effectively detect whether abnormal blockage occurs in the air conditioner system, which is conducive to taking relevant protective measures in time when blockage is detected, thereby improving the operating reliability of the air conditioner.

[0005] To achieve the above-mentioned purpose, an embodiment of the present invention provides an air conditioner, including a circulation system formed by a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger;

[0006] Controller for:

[0007] In response to a heating instruction, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters a heating mode start-up phase;

[0008] Controlling the compressor to adjust the current operating frequency to a preset starting frequency, and adjusting the current opening of the electronic expansion valve to a preset initial opening;

[0009] When the current operating frequency of the compressor is the preset starting frequency, the average operating power of the compressor in a preset time period before the current moment is calculated in real time as the average starting power;

[0010] If the decrease of the current average starting power compared to the average starting power in the previous heating mode starting stage exceeds a first preset decrease threshold, it is determined that oil blockage occurs in the circulation system in the heating stage.

[0011] As an improvement of the above solution, after determining that oil blockage occurs in the circulation system during the heating stage, the controller is further configured to:

[0012] Adjust the current opening of the electronic expansion valve to a preset maximum opening, and after reaching the maximum opening, control the electronic expansion valve to perform at least one reciprocating fluctuation adjustment on the current opening; wherein the reciprocating fluctuation adjustment is: control the current opening of the electronic expansion valve to decrease by a preset opening adjustment step and then increase by a preset opening adjustment step;

[0013] After the reciprocating fluctuation adjustment, the current opening of the electronic expansion valve is maintained as the preset maximum opening.

[0014] As an improvement of the above solution, after determining that oil blockage occurs in the circulation system during the heating stage, the controller is further configured to:

[0015] The counted number of oil blockages is incremented by one; wherein the initial value of the number of oil blockages is zero;

[0016] When the oil blockage frequency reaches a preset alarm frequency threshold, the air conditioner is controlled to shut down and a fault alarm message is pushed.

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

[0018] In response to a defrost instruction, the four-way valve is switched to conduct the reverse defrost circuit, the air conditioner enters a defrost mode, and the compressor is controlled to adjust the current operating frequency to a preset defrost frequency;

[0019] When the current operating frequency of the compressor is the preset defrosting frequency, the operating power of the compressor is detected in real time within each preset detection cycle;

[0020] If the operating power of the current detection cycle decreases by more than a second preset decrease threshold compared to the operating power of the previous detection cycle, it is determined that oil blockage occurs in the circulation system during the defrosting stage.

[0021] As an improvement of the above solution, the air conditioner further comprises an outdoor temperature sensor, which is arranged on the coil surface of the outdoor heat exchanger and is used to collect the outdoor coil temperature of the outdoor heat exchanger;

[0022] The controller is also used for:

[0023] When the current operating frequency of the compressor is the preset defrosting frequency, the outdoor coil temperature is also detected in real time within each preset detection cycle;

[0024] After determining that the circulation system is blocked by oil during the defrosting stage, comparing the outdoor coil temperature with a preset effective defrosting temperature;

[0025] If the outdoor coil temperature is greater than the preset effective defrosting temperature, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters the heating mode startup stage;

[0026] If the outdoor coil temperature is less than or equal to the preset effective defrost temperature, the air conditioner is controlled to shut down and the current opening of the electronic expansion valve is adjusted to the preset maximum opening; after the preset shutdown time, the air conditioner is controlled to start and re-enter the defrost mode.

[0027] As an improvement of the above solution, after determining that the circulation system is blocked by oil during the defrosting stage, if the outdoor coil temperature is lower than the preset effective defrosting temperature, the controller is further configured to:

[0028] The statistical number of oil blockage times is added by one.

[0029] As an improvement of the above scheme, the circulation system also includes a filter and a one-way valve, the filter is arranged between the electronic expansion valve and the outdoor heat exchanger, the inlet of the one-way valve is connected to the electronic expansion valve, and the outlet of the one-way valve is connected to the outdoor heat exchanger.

[0030] The embodiment of the present invention further provides an oil blockage detection method for an air conditioner, wherein the air conditioner includes a circulation system formed by a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger;

[0031] The method comprises:

[0032] In response to a heating instruction, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters a heating mode start-up phase;

[0033] Controlling the compressor to adjust the current operating frequency to a preset starting frequency, and adjusting the current opening of the electronic expansion valve to a preset initial opening;

[0034] When the current operating frequency of the compressor is the preset starting frequency, the average operating power of the compressor in a preset time period before the current moment is calculated as the average starting power;

[0035] If the decrease of the current average starting power compared to the average starting power in the previous heating mode starting stage exceeds a first preset decrease threshold, it is determined that oil blockage occurs in the circulation system in the heating stage.

[0036] As an improvement of the above solution, after determining that oil blockage occurs in the circulation system during the heating stage, the method further includes:

[0037] Adjust the current opening of the electronic expansion valve to a preset maximum opening, and after reaching the maximum opening, control the electronic expansion valve to perform at least one reciprocating fluctuation adjustment on the current opening; wherein the reciprocating fluctuation adjustment is: control the current opening of the electronic expansion valve to decrease by a preset opening adjustment step and then increase by a preset opening adjustment step;

[0038] After the reciprocating fluctuation adjustment, the current opening of the electronic expansion valve is maintained as the preset maximum opening.

[0039] As an improvement of the above solution, the air conditioner further comprises an outdoor temperature sensor, which is arranged on the coil surface of the outdoor heat exchanger and is used to collect the outdoor coil temperature of the outdoor heat exchanger;

[0040] The method further comprises:

[0041] In response to a defrost instruction, the four-way valve is switched to conduct the reverse defrost circuit, the air conditioner enters a defrost mode, and the compressor is controlled to adjust the current operating frequency to a preset defrost frequency;

[0042] When the current operating frequency of the compressor is the preset defrosting frequency, in each preset detection cycle, the operating power of the compressor and the outdoor coil temperature are detected in real time;

[0043] If the operating power of the current detection cycle decreases by more than a second preset decrease threshold compared to the operating power of the previous detection cycle, it is determined that the circulation system is blocked by oil during the defrosting stage;

[0044] After determining that the circulation system is blocked by oil during the defrosting stage, comparing the outdoor coil temperature with a preset effective defrosting temperature;

[0045] If the outdoor coil temperature is greater than the preset effective defrosting temperature, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters the heating mode startup stage;

[0046] If the outdoor coil temperature is less than or equal to the preset effective defrost temperature, the air conditioner is controlled to shut down and the current opening of the electronic expansion valve is adjusted to the preset maximum opening; after the preset shutdown time, the air conditioner is controlled to start and re-enter the defrost mode.

[0047] Compared with the prior art, the air conditioner and the oil blockage detection method of the air conditioner disclosed in the present invention 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. In response to a heating instruction, the four-way valve is switched to make the heating circuit conductive, and the air conditioner enters the heating mode startup phase; the compressor is controlled to adjust the current operating frequency to a preset startup frequency, and the current opening of the electronic expansion valve is adjusted to a preset initial opening; when the current operating frequency of the compressor is the preset startup frequency, the average operating power of the compressor in a preset time period before the current moment is calculated in real time as the average startup power; if the current average startup power drops more than the first preset drop threshold compared with the average startup power in the previous heating mode startup phase, it is determined that the circulation system is oil blocked in the heating phase. The technical means of the embodiments of the present invention can effectively detect whether the air conditioner system is abnormally blocked in the heating mode, which is conducive to taking relevant protective measures in time when the blockage phenomenon is detected, and improving the operating reliability of the air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a structural schematic diagram of an air conditioner provided by an embodiment of the present invention;

[0049] Figure 2 is a schematic structural diagram of a circulation system of an air conditioner in an embodiment of the present invention;

[0050] Figure 3 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 4 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 5 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 6 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 7 is a schematic flow chart of the work performed by the controller in the fifth preferred implementation mode in the embodiment of the present invention;

[0055] Figure 8 is a schematic flow chart of the work performed by the controller in the sixth preferred implementation mode in the embodiment of the present invention;

[0056] Fig. 9is a schematic flow chart of the work performed by the controller in the seventh preferred implementation mode in the embodiment of the present invention;

[0057] Fig.10 It is a schematic diagram of a preferred structure of the circulation system of the air conditioner in the 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 structural schematic diagram of an air conditioner provided in Example 1 of the present invention.

[0060] An embodiment of the present invention provides an air conditioner 10, which includes a circulation system 20, wherein 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.

[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] See also Figure 1 The air conditioner 10 further includes a controller 30, which is connected to each component in the circulation system 20, so as to acquire and analyze each information and issue relevant control instructions.

[0066] Specifically, see Figure 3 , 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 30 is used to perform steps S11 to S14:

[0067] S11, in response to a heating instruction, switching the four-way valve to conduct the heating circuit, and the air conditioner enters a heating mode start-up phase;

[0068] S12, controlling the compressor to adjust the current operating frequency to a preset starting frequency, and adjusting the current opening of the electronic expansion valve to a preset initial opening;

[0069] S13, when the current operating frequency of the compressor is the preset starting frequency, calculating in real time the average operating power of the compressor in a preset time period before the current moment as the average starting power;

[0070] S14: If the decrease of the current average starting power compared with the average starting power in the previous heating mode starting stage exceeds a first preset decrease threshold, it is determined that the circulation system is blocked by oil in the heating stage.

[0071] The embodiment of the present invention is applied to the operation process of the air conditioner in the heating mode. When the air conditioner is in the operating state, when the controller 30 receives a heating command, it responds to the defrost command and controls the four-way valve 22 to be in the energized state, so that the A port and the B port are connected, the C port and the D port are connected, the heating circuit is turned on, and the air conditioner enters the heating mode.

[0072] When the air conditioner enters the heating mode, it is first in the startup phase, and the controller 30 controls the compressor 21 to adjust its current operating frequency F to the preset startup frequency F. on , and controls the electronic expansion valve 24 to adjust its current opening N to the preset initial opening N on , the circulation system performs normal heating operation.

[0073] It should be noted that the starting frequency F on and the initial opening N on It is preset, and its specific value can be set according to the actual application situation, and is not specifically limited here.

[0074] Furthermore, when the current operating frequency of the compressor 21 reaches the preset starting frequency F on When the controller 30 obtains the operating power of the compressor 21 in a certain period of time before the current moment, the average operating power in the period of time is calculated and recorded as the average starting power P avg,i , and in the heating mode startup phase, the controller 30 updates the average startup power P in real time avg,i .

[0075] Optionally, the preset time period τ is set to 5 to 15 seconds. Of course, its specific value can also be set according to actual needs without affecting the beneficial effects achieved by the present invention.

[0076] The current average starting power P is calculated avg,i Afterwards, the controller 30 obtains the average starting power P in the previous heating mode starting phase. avg,i-1 , and according to the current average starting power P avg,i and the average starting power P of the previous heating mode startup phase avg,i-1 , calculate the average starting power drop δ.

[0077] The decrease δ of the current average starting power compared to the average starting power in the previous heating mode starting phase satisfies the following calculation formula:

[0078]

[0079] It should be noted that the average starting power P in the previous heating mode startup phase is avg,i-1Specifically, the average operating power of the compressor in a preset time period τ before the end of the start-up phase of the previous heating mode is selected.

[0080] Furthermore, a first preset drop threshold η1% is pre-set to characterize the drop in the average starting power of the compressor. The controller 30 determines whether the compressor operating power has dropped significantly based on the calculated average starting power drop δ, and further determines whether the electronic expansion valve has oil blockage.

[0081] In one case, if δ≥η1%, it indicates that the electronic expansion valve 24 is blocked by oil. In another case, if δ<η1%, it indicates that the electronic expansion valve 24 is not blocked by oil or is slightly blocked by oil.

[0082] Optionally, the first preset drop threshold is set to be between 30% and 40%. Of course, the specific value can also be set according to actual needs without affecting the beneficial effects achieved by the present invention.

[0083] The embodiment of the present invention provides an air conditioner, which responds to a heating instruction, switches the four-way valve to make the heating circuit conductive, and the air conditioner enters the heating mode startup phase; controls the compressor to adjust the current operating frequency to the preset startup frequency, and adjusts the current opening of the electronic expansion valve to the preset initial opening; when the current operating frequency of the compressor is the preset startup frequency, the average operating power of the compressor in the preset time period before the current moment is calculated in real time as the average startup power; if the current average startup power drops more than the first preset drop threshold compared with the average startup power in the previous heating mode startup phase, it is determined that the circulation system is blocked by oil in the heating phase. The technical means of the embodiment of the present invention can effectively detect whether the air conditioner system is abnormally blocked in the heating mode, which is conducive to taking relevant protective measures in time when the blockage is detected, thereby improving the operating reliability of the air conditioner.

[0084] Preferably, see Figure 4 , is a flow chart of the work performed by the controller in the second preferred embodiment of the present invention. When δ<η1% is satisfied, it is further determined whether the start-up phase of the heating mode is completed. If so, the average operating power P of the compressor in the last preset time period τ of the start-up phase is recorded. avg , providing a data basis for calculating the average startup power drop δ in the next heating mode startup phase. If not, recalculate the average startup power of the compressor in the preset time period before the current moment, and recalculate and judge the average startup power drop δ.

[0085] Optionally, the following method is used to determine whether the start-up phase of the heating mode is completed: presetting the start-up preset time t set , determine the duration t of the air conditioner in the startup phaseon The start preset time t set If t on ≥t set , indicating that the startup is completed; if t on <t set , indicating that the startup has not yet been completed.

[0086] Among them, the start preset time t set The value is set to 120-180s. Of course, it can also be set according to the actual situation and is not specifically limited here.

[0087] As a preferred embodiment, see Figure 5 , is a flowchart of the work performed by the controller in the embodiment of the present invention under the third preferred implementation mode. The embodiment of the present invention is further implemented on the basis of the above embodiment. In step S14, that is, after determining that the circulation system is blocked by oil during the heating stage, the controller is further used to perform steps S15 and S16:

[0088] S15, adjusting the current opening of the electronic expansion valve to a preset maximum opening, and after reaching the maximum opening, controlling the electronic expansion valve to perform at least one reciprocating fluctuation adjustment on the current opening; wherein the reciprocating fluctuation adjustment is: controlling the current opening of the electronic expansion valve to decrease by a preset opening adjustment step and then increase by a preset opening adjustment step;

[0089] S16. After the reciprocating fluctuation adjustment, maintaining the current opening of the electronic expansion valve as the preset maximum opening.

[0090] In the embodiment of the present invention, in the heating mode of the air conditioner, if it is determined that oil blockage occurs, the electronic expansion valve 24 is controlled to adjust its current opening to the preset maximum opening N. max , that is, the electronic expansion valve is fully opened, and the throttling and pressure reduction function is turned off. Afterwards, the current opening of the electronic expansion valve is controlled to decrease by a preset opening adjustment step △N and then increase by a preset opening adjustment step △N, that is, in the opening interval [N max -△N,N max ] reciprocates at least once. Afterwards, the current opening of the electronic expansion valve 24 is maintained at the maximum opening N max .

[0091] Optionally, the preset maximum opening N max The maximum opening N is set to 480 steps, and the preset opening adjustment step length △N is set to 50 steps. Of course, the above values ​​are only for example. max The value of the opening adjustment step △N can be set according to actual conditions and is not specifically limited here.

[0092] By adopting the technical means of the embodiment of the present invention, after detecting that oil blockage occurs in the air conditioner, the electronic expansion valve is controlled to be fully opened and the throttling and pressure reduction function is turned off. The refrigerant maintains its original state when flowing through the electronic expansion valve 24 without throttling and reducing the pressure, which is conducive to alleviating or eliminating the oil blockage phenomenon.

[0093] As a preferred embodiment, see Figure 6 , is a flowchart of the work performed by the controller in the fourth preferred implementation mode in the embodiment of the present invention. Based on any of the above embodiments, in step S14, that is, after determining that the circulation system is blocked by oil during the heating stage, the controller is further configured to perform steps S17 and S18:

[0094] S17, adding one to the counted number of oil blockages; wherein the initial value of the number of oil blockages is zero;

[0095] S18. When the oil blockage frequency reaches a preset alarm frequency threshold, the air conditioner is controlled to shut down and a fault alarm message is pushed.

[0096] In the embodiment of the present invention, the controller 30 records an oil blockage frequency parameter j and sets the initial value j = 0. When it is determined that the circulation system is oil blocked, the oil blockage frequency j is increased by one, j = j + 1, so as to count the number of oil blockages of the air conditioner.

[0097] Furthermore, when the oil blockage times j reaches the preset alarm times threshold, indicating that the air conditioner has experienced multiple oil blockages, the air conditioner is controlled to shut down to prevent the air conditioner from running abnormally under the condition of oil blockage. In addition, the controller pushes the preset fault alarm information to remind the user to check and repair.

[0098] Optionally, the alarm number threshold is set to 3 times. Of course, the above value is only for example, and the alarm number threshold can also be set according to actual application conditions and user needs, and is not specifically limited here.

[0099] By adopting the technical means of the embodiment of the present invention, the control sequence of the air conditioner is to detect oil blockage, alleviate or eliminate oil blockage, and shut down for oil blockage protection. The process is gradual, that is, first detect whether oil blockage occurs, and give priority to alleviating or eliminating oil blockage under the premise that oil blockage occurs and does not threaten the safety of the air conditioner. If there is no effect, then shut down for protection, which effectively ensures the operating stability and reliability of the air conditioner and improves the user experience.

[0100] As a preferred embodiment, see Figure 7 , is a flowchart of the work performed by the controller in the fifth preferred implementation mode in the embodiment of the present invention. The embodiment of the present invention is implemented on the basis of any of the above embodiments, and the controller is further used to perform steps S21 to S23:

[0101] S21, in response to a defrost instruction, switching the four-way valve to conduct the reverse defrost circuit, the air conditioner enters a defrost mode, and controlling the compressor to adjust the current operating frequency to a preset defrost frequency;

[0102] S22, when the current operating frequency of the compressor is the preset defrosting frequency, detecting the operating power of the compressor in real time within each preset detection cycle;

[0103] S23: If the operating power of the current detection cycle decreases by more than a second preset decrease threshold compared with the operating power of the previous detection cycle, it is determined that oil blockage occurs in the circulation system during the defrosting stage.

[0104] The embodiment of the present invention is applied to the case where defrosting is required during the operation 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 activated. In response to the defrosting instruction, the controller 30 controls the four-way valve 22 to be in a 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.

[0105] After the air conditioner enters the defrost mode, the controller 30 controls the compressor 21 to adjust its current operating frequency to the preset defrost frequency F. d , and adjust the current opening N of the electronic expansion valve 24 to the preset maximum opening N max That is, the electronic expansion valve is fully opened, the throttling and pressure reduction function is closed, and the circulation system performs a reverse cycle defrosting operation.

[0106] It should be noted that the defrosting frequency F d It is preset, and its specific value can be set according to the actual application situation, and is not specifically limited here.

[0107] Furthermore, when the current operating frequency of the compressor 21 reaches the preset defrosting frequency F d When a certain time is taken as a detection cycle, the controller detects the current operating power P of the compressor 21 in real time in each detection cycle. i .

[0108] Optionally, the duration of the detection cycle is set to 5 to 15 seconds. Of course, the specific value can also be set according to actual needs without affecting the beneficial effects achieved by the present invention.

[0109] After calculating the operating power P of the current detection cycle i Afterwards, the controller 30 obtains the operating power P recorded in the previous detection cycle i-1 , and according to the operating power P of the current detection cycle iand the operating power P recorded in the previous detection cycle i-1 , calculate the operating power drop δ′.

[0110] Among them, the operating power P of the current detection cycle i Compared with the operating power P recorded in the previous detection cycle i-1 The decline δ′ satisfies the following calculation formula:

[0111]

[0112] Furthermore, a second preset drop threshold η2% is pre-set to characterize the magnitude of the drop in the compressor operating power. The controller 30 determines whether the compressor operating power has dropped significantly based on the calculated operating power drop δ′, and further determines whether the electronic expansion valve has oil blockage.

[0113] In one case, if δ′≥η2%, it indicates that the electronic expansion valve 24 is blocked by oil. In another case, if δ′<η2%, it indicates that the electronic expansion valve 24 is not blocked by oil or is slightly blocked by oil. In this case, the operating power of the compressor in the current detection cycle is re-detected, and the operating power drop δ′ is recalculated and judged.

[0114] Optionally, the second preset drop threshold is set to be between 30% and 40%. Of course, the specific value can also be set according to actual needs without affecting the beneficial effects achieved by the present invention.

[0115] By adopting the technical means of the embodiments of the present invention, it is possible to effectively detect whether abnormal blockage occurs in the air conditioner system in the defrost mode, which is conducive to taking relevant protective measures in time when blockage is detected, thereby improving the operating reliability of the air conditioner.

[0116] As a preferred embodiment, see Figure 2 The air conditioner 10 further includes an outdoor temperature sensor 40, which 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 . See Figure 8 , is a flowchart of the work performed by the controller in the sixth preferred implementation mode in an embodiment of the present invention, and the controller 30 is further configured to perform steps S34 to S37:

[0117] S34, when the current operating frequency of the compressor is the preset defrosting frequency, in each preset detection cycle, the outdoor coil temperature is also detected in real time;

[0118] S35, after determining that the circulation system is blocked by oil during the defrosting stage, comparing the outdoor coil temperature with a preset effective defrosting temperature;

[0119] S36, if the outdoor coil temperature is greater than the preset effective defrosting temperature, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters the heating mode start-up stage;

[0120] S37. If the outdoor coil temperature is less than or equal to the preset effective defrost temperature, the air conditioner is controlled to shut down, and the current opening of the electronic expansion valve is adjusted to the preset maximum opening; after the preset shutdown time, the air conditioner is controlled to start and re-enter the defrost mode.

[0121] In the embodiment of the present invention, when the current operating frequency of the compressor 21 reaches the preset defrosting frequency F d When the controller 30 obtains the outdoor coil temperature T collected by the outdoor heat exchanger 25 in each detection cycle, out .

[0122] Furthermore, the effective defrosting temperature T is preset. out_set , which is used to characterize the outdoor coil temperature when the frost layer of the outdoor unit melts. When it is determined that the circulation system is blocked by oil during the defrosting stage, according to the outdoor coil temperature T out The countermeasures to the oil blockage phenomenon are determined based on the relationship between the temperature and the preset effective defrost temperature.

[0123] Specifically, according to the collected outdoor coil temperature T out , if T out >T out_set , indicating that the frost layer has been effectively melted, the air conditioner is controlled to exit the defrost mode in advance, the four-way valve is switched to make the heating circuit conductive, and the air conditioner enters the heating mode startup phase. Then, according to the above embodiment, the oil blockage phenomenon is detected in the heating mode startup phase, and when the oil blockage phenomenon is detected, measures such as mitigation and elimination and shutdown protection are taken.

[0124] If T out ≤T out_set , indicating that the frost layer has not been effectively melted. At this time, the air conditioner cannot perform normal defrosting operation, so the air conditioner is controlled to shut down and the current opening of the electronic expansion valve 24 is adjusted to the preset maximum opening N max , the electronic expansion valve is fully opened, the throttling and pressure reduction function is turned off, and the refrigerant maintains the original state when flowing through the electronic expansion valve 24 without throttling and pressure reduction, which is conducive to alleviating or eliminating the oil blockage phenomenon. After the preset shutdown time t, the air conditioner is controlled to start and re-enter the defrost mode.

[0125] Optionally, the effective defrosting temperature T out_set The temperature is set to 0-5° C. Of course, the above values ​​are only examples, and the values ​​can also be set according to the actual application situation, and are not specifically limited here.

[0126] Optionally, the preset time length t is set to 1 minute. Of course, the above values ​​are only examples, and their values ​​can also be set according to actual application conditions, and are not specifically limited here.

[0127] Preferably, see Fig. 9 , is a flow chart of the work performed by the controller in the seventh preferred implementation mode in an embodiment of the present invention. After step S37, that is, after determining that oil blockage occurs in the circulation system during the defrosting stage, if the outdoor coil temperature is lower than the preset effective defrosting temperature, the controller is further configured to execute step S38:

[0128] S38, adding one to the counted number of oil blockages.

[0129] In an embodiment of the present invention, when it is determined that the air conditioner is blocked by oil during the defrost stage and the frost layer has not been effectively melted at this time, the current oil blockage situation is recorded in the oil blockage times, so that when it is subsequently determined that the oil blockage times j reaches the preset alarm times threshold, the air conditioner is controlled to shut down and the preset fault alarm information is pushed to remind the user to check and repair.

[0130] As a preferred embodiment, see Fig.10 , is a schematic diagram of a preferred structure of the circulation system of the air conditioner in the embodiment of the present invention, wherein the circulation system 20 further comprises 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. The circulation system 20 further comprises a one-way valve 28, wherein the one-way valve 28 is connected in parallel with the second filter 27, that is, the inlet of the one-way valve 28 is connected to the electronic expansion valve 24, and the outlet of the one-way valve 28 is connected to the outdoor heat exchanger 25.

[0131] When the air conditioner is in heating mode, 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 passes through the one-way valve 28 and the filter 27 in parallel and enters the outdoor heat exchanger 25. After being evaporated into gas through heat exchange, the refrigerant enters the compressor for intake, completing the whole cycle.

[0132] By adopting the technical means of the embodiment of the present invention and adding a bypass branch of the filter 27, the oil blockage phenomenon on the filter screen of the compressor exhaust after passing through the electronic expansion valve in the heating mode can be effectively alleviated, thereby ensuring the smooth start-up phase of the heating mode.

[0133] The embodiment of the present invention further provides an oil blockage detection method for an air conditioner, wherein the air conditioner includes a circulation system formed by a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger;

[0134] The method comprises:

[0135] In response to a heating instruction, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters a heating mode start-up phase;

[0136] Controlling the compressor to adjust the current operating frequency to a preset starting frequency, and adjusting the current opening of the electronic expansion valve to a preset initial opening;

[0137] When the current operating frequency of the compressor is the preset starting frequency, the average operating power of the compressor in a preset time period before the current moment is calculated as the average starting power;

[0138] If the decrease of the current average starting power compared to the average starting power in the previous heating mode starting stage exceeds a first preset decrease threshold, it is determined that oil blockage occurs in the circulation system in the heating stage.

[0139] By adopting the technical means of the embodiments of the present invention, it is possible to effectively detect whether abnormal blockage occurs in the air conditioner system in the heating mode, which is conducive to taking relevant protective measures in time when blockage is detected, thereby improving the operating reliability of the air conditioner.

[0140] Preferably, after determining that oil blockage occurs in the circulation system during the heating stage, the method further includes:

[0141] Adjust the current opening of the electronic expansion valve to a preset maximum opening, and after reaching the maximum opening, control the electronic expansion valve to perform at least one reciprocating fluctuation adjustment on the current opening; wherein the reciprocating fluctuation adjustment is: control the current opening of the electronic expansion valve to decrease by a preset opening adjustment step and then increase by a preset opening adjustment step;

[0142] After the reciprocating fluctuation adjustment, the current opening of the electronic expansion valve is maintained as a preset maximum opening.

[0143] Preferably, after determining that oil blockage occurs in the circulation system during the heating stage, the method further includes:

[0144] The counted number of oil blockages is incremented by one; wherein the initial value of the number of oil blockages is zero;

[0145] When the oil blockage frequency reaches a preset alarm frequency threshold, the air conditioner is controlled to shut down and a fault alarm message is pushed.

[0146] By adopting the technical means of the embodiment of the present invention, the control sequence of the air conditioner is to detect oil blockage - alleviate or eliminate oil blockage - shut down for oil blockage protection. The process is gradual, that is, first detect whether oil blockage occurs, and give priority to alleviating or eliminating oil blockage under the premise that oil blockage occurs and does not threaten the safety of the air conditioner. If there is no effect, shut down for protection, which effectively ensures the operating stability and reliability of the air conditioner and improves the user experience.

[0147] As a preferred embodiment, the air conditioner further comprises an outdoor temperature sensor, which is arranged on the coil surface of the outdoor heat exchanger and is used to collect the outdoor coil temperature of the outdoor heat exchanger;

[0148] The method further comprises:

[0149] In response to a defrost instruction, the four-way valve is switched to conduct the reverse defrost circuit, the air conditioner enters a defrost mode, and the compressor is controlled to adjust the current operating frequency to a preset defrost frequency;

[0150] When the current operating frequency of the compressor is the preset defrosting frequency, in each preset detection cycle, the operating power of the compressor and the outdoor coil temperature are detected in real time;

[0151] If the operating power of the current detection cycle decreases by more than a second preset decrease threshold compared to the operating power of the previous detection cycle, it is determined that the circulation system is blocked by oil during the defrosting stage;

[0152] After determining that the circulation system is blocked by oil during the defrosting stage, comparing the outdoor coil temperature with a preset effective defrosting temperature;

[0153] If the outdoor coil temperature is greater than the preset effective defrosting temperature, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters the heating mode startup stage;

[0154] If the outdoor coil temperature is less than or equal to the preset effective defrost temperature, the air conditioner is controlled to shut down and the current opening of the electronic expansion valve is adjusted to the preset maximum opening; after the preset shutdown time, the air conditioner is controlled to start and re-enter the defrost mode.

[0155] Preferably, after determining that oil blockage occurs in the circulation system during the defrosting stage, if the outdoor coil temperature is lower than the preset effective defrosting temperature, the controller is further configured to:

[0156] The statistical number of oil blockage times is added by one.

[0157] By adopting the technical means of the embodiments of the present invention, it is possible to effectively detect whether abnormal blockage occurs in the air conditioner system in the defrost mode, and take relevant protective measures in time when blockage is detected, thereby improving the operating reliability of the air conditioner.

[0158] It should be noted that the air conditioner oil blockage detection method provided in the embodiment of the present invention has the same process steps as those executed by the controller of the 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 repeated here.

[0159] 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.

[0160] 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: A circulation system comprising a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger; Controller for: In response to a heating instruction, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters a heating mode start-up phase; Controlling the compressor to adjust the current operating frequency to a preset starting frequency, and adjusting the current opening of the electronic expansion valve to a preset initial opening; When the current operating frequency of the compressor is the preset starting frequency, the average operating power of the compressor in a preset time period before the current moment is calculated in real time as the average starting power; If the decrease of the current average starting power compared with the average starting power in the previous heating mode starting stage exceeds a first preset decrease threshold, it is determined that the circulation system is blocked by oil in the heating stage; After determining that oil blockage occurs in the circulation system during the heating stage, the controller is further configured to: Adjust the current opening of the electronic expansion valve to a preset maximum opening, and after reaching the maximum opening, control the electronic expansion valve to perform at least one reciprocating fluctuation adjustment on the current opening; wherein the reciprocating fluctuation adjustment is: control the current opening of the electronic expansion valve to decrease by a preset opening adjustment step and then increase by a preset opening adjustment step; After the reciprocating fluctuation adjustment, the current opening of the electronic expansion valve is maintained as the preset maximum opening.

2. The air conditioner according to claim 1, characterized in that: After determining that oil blockage occurs in the circulation system during the heating stage, the controller is further configured to: The counted number of oil blockages is incremented by one; wherein the initial value of the number of oil blockages is zero; When the oil blockage frequency reaches a preset alarm frequency threshold, the air conditioner is controlled to shut down and a fault alarm message is pushed.

3. The air conditioner according to claim 2, characterized in that: The controller is also used for: In response to a defrost instruction, the four-way valve is switched to conduct the reverse defrost circuit, the air conditioner enters a defrost mode, and the compressor is controlled to adjust the current operating frequency to a preset defrost frequency; When the current operating frequency of the compressor is the preset defrosting frequency, the operating power of the compressor is detected in real time within each preset detection cycle; If the operating power of the current detection cycle decreases by more than a second preset decrease threshold compared to the operating power of the previous detection cycle, it is determined that oil blockage occurs in the circulation system during the defrosting stage.

4. The air conditioner according to claim 3, characterized in that: The air conditioner further comprises an outdoor temperature sensor, which is arranged on the coil surface of the outdoor heat exchanger and is used to collect the outdoor coil temperature of the outdoor heat exchanger; The controller is also used for: When the current operating frequency of the compressor is the preset defrosting frequency, the outdoor coil temperature is also detected in real time within each preset detection cycle; After determining that the circulation system is blocked by oil during the defrosting stage, comparing the outdoor coil temperature with a preset effective defrosting temperature; If the outdoor coil temperature is greater than the preset effective defrosting temperature, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters the heating mode startup stage; If the outdoor coil temperature is less than or equal to the preset effective defrosting temperature, the air conditioner is controlled to shut down, and the current opening of the electronic expansion valve is adjusted to a preset maximum opening; After the preset shutdown time, the air conditioner is controlled to start and re-enter the defrost mode.

5. The air conditioner according to claim 4, characterized in that: After determining that oil blockage occurs in the circulation system during the defrosting stage, if the outdoor coil temperature is lower than the preset effective defrosting temperature, the controller is further configured to: The statistical number of oil blockage times is added by one.

6. The air conditioner according to claim 1, characterized in that: The circulation system further comprises a filter and a one-way valve, wherein the filter is arranged between the electronic expansion valve and the outdoor heat exchanger, the inlet of the one-way valve is connected to the electronic expansion valve, and the outlet of the one-way valve is connected to the outdoor heat exchanger.

7. A method for detecting oil blockage in an air conditioner, characterized in that: The air conditioner includes a circulation system formed by a compressor, a four-way valve, an indoor heat exchanger, an electronic expansion valve and an outdoor heat exchanger; The method comprises: In response to a heating instruction, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters a heating mode start-up phase; Controlling the compressor to adjust the current operating frequency to a preset starting frequency, and adjusting the current opening of the electronic expansion valve to a preset initial opening; When the current operating frequency of the compressor is the preset starting frequency, the average operating power of the compressor in a preset time period before the current moment is calculated as the average starting power; If the decrease of the current average starting power compared with the average starting power in the previous heating mode starting stage exceeds a first preset decrease threshold, it is determined that the circulation system is blocked by oil in the heating stage; After determining that oil blockage occurs in the circulation system during the heating stage, the method further includes: Adjust the current opening of the electronic expansion valve to a preset maximum opening, and after reaching the maximum opening, control the electronic expansion valve to perform at least one reciprocating fluctuation adjustment on the current opening; wherein the reciprocating fluctuation adjustment is: control the current opening of the electronic expansion valve to decrease by a preset opening adjustment step and then increase by a preset opening adjustment step; After the reciprocating fluctuation adjustment, the current opening of the electronic expansion valve is maintained as the preset maximum opening.

8. The oil blockage detection method for an air conditioner according to claim 7, characterized in that: The air conditioner further comprises an outdoor temperature sensor, which is arranged on the coil surface of the outdoor heat exchanger and is used to collect the outdoor coil temperature of the outdoor heat exchanger; The method further comprises: In response to a defrost instruction, the four-way valve is switched to conduct the reverse defrost circuit, the air conditioner enters a defrost mode, and the compressor is controlled to adjust the current operating frequency to a preset defrost frequency; When the current operating frequency of the compressor is the preset defrosting frequency, in each preset detection cycle, the operating power of the compressor and the outdoor coil temperature are detected in real time; If the operating power of the current detection cycle decreases by more than a second preset decrease threshold compared to the operating power of the previous detection cycle, it is determined that the circulation system is blocked by oil during the defrosting stage; After determining that the circulation system is blocked by oil during the defrosting stage, comparing the outdoor coil temperature with a preset effective defrosting temperature; If the outdoor coil temperature is greater than the preset effective defrosting temperature, the four-way valve is switched to conduct the heating circuit, and the air conditioner enters the heating mode startup stage; If the outdoor coil temperature is less than or equal to the preset effective defrost temperature, the air conditioner is controlled to shut down and the current opening of the electronic expansion valve is adjusted to the preset maximum opening; after the preset shutdown time, the air conditioner is controlled to start and re-enter the defrost mode.

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