CN115371204A

CN115371204A - Electronic expansion valve fault determination method and related device

Info

Publication number: CN115371204A
Application number: CN202211025368.4A
Authority: CN
Inventors: 王穗; 刘合心; 张稳
Original assignee: Ningbo Aux Electric Co Ltd
Current assignee: Ningbo Aux Electric Co Ltd
Priority date: 2022-08-25
Filing date: 2022-08-25
Publication date: 2022-11-22
Anticipated expiration: 2042-08-25
Also published as: CN115371204B

Abstract

The embodiment of the invention provides a method for judging faults of an electronic expansion valve and a related device, and relates to the technical field of air conditioner control. Determining a target indoor unit in a standby state under the condition that the time length for a compressor of an outdoor unit of a multi-connected air-conditioning system to exit a starting platform reaches a preset time length; acquiring the operation parameters of the target indoor unit at the current moment according to the current operation mode of the multi-connected air-conditioning system; and judging whether the electronic expansion valve in the target indoor unit has a fault or not according to the operation parameters. The method can automatically realize the troubleshooting of the electronic expansion valve in the multi-connected air-conditioning system, avoids the manual detection, further can reduce the manual labor and improve the fault detection efficiency.

Description

Electronic expansion valve fault determination method and related device

Technical Field

The invention relates to the technical field of air conditioner control, in particular to a method for judging faults of an electronic expansion valve and a related device.

Background

When the multi-connected air-conditioning system operates, the outdoor units often provide refrigerant flow, and the indoor units control the on-off of the refrigerant flow and the flow adjustment through electronic expansion valves, so that if the electronic expansion valves in the multi-connected air-conditioning system have faults, the refrigerant flow control precision of the multi-connected air-conditioning system is reduced, the operation state of the multi-connected air-conditioning system is influenced, and even the operation safety of the multi-connected air-conditioning system is reduced.

In the prior art, a worker often needs to perform troubleshooting on an electronic expansion valve of the multi-connected air conditioning system in a manual detection mode, and the method increases manual labor and reduces the failure detection efficiency of the multi-connected air conditioning system.

Disclosure of Invention

The invention solves the problem of how to realize troubleshooting of an electronic expansion valve of a multi-connected air-conditioning system while avoiding manual detection.

In order to solve the above problems, embodiments of the present invention provide a method and a related device for determining a failure of an electronic expansion valve, so as to avoid troubleshooting the electronic expansion valve for a multi-connected air conditioning system in a manual detection manner, thereby reducing manual labor and improving failure detection efficiency.

In a first aspect, the present invention provides a method for determining a failure of an electronic expansion valve, which is applied to a multi-connected air conditioning system, where the multi-connected air conditioning system includes an outdoor unit and a plurality of indoor units connected to the outdoor unit, and the method includes:

determining a target indoor unit in a standby state under the condition that the time length for the compressor of the outdoor unit to exit the starting platform reaches a preset time length;

acquiring the operation parameters of the target indoor unit at the current moment according to the current operation mode of the multi-connected air-conditioning system;

and judging whether the electronic expansion valve in the target indoor unit has a fault or not according to the operation parameters.

According to the method for judging the fault of the electronic expansion valve, provided by the embodiment of the invention, when the time length of the compressor of the outdoor unit exiting the starting platform reaches the preset time length, the target indoor unit in a standby state is determined, the operation parameters of the target indoor unit at the current moment are obtained according to the current operation mode of the multi-connected air-conditioning system, and therefore whether the electronic expansion valve in the target indoor unit has the fault or not is determined according to the operation parameters. Whether the electronic expansion valve has a fault or not is determined according to the operation parameters of the target indoor unit under the condition that the time length for the compressor of the outdoor unit to exit the starting platform reaches the preset time length, so that the electronic expansion valve in the multi-connected air-conditioning system can be automatically checked, the manual detection is avoided, the manual labor can be reduced, and the fault detection efficiency is improved.

In an optional embodiment, the obtaining, according to the current operation mode of the multi-connected air conditioning system, operation parameters of the target indoor unit at the current time includes:

under the condition that the current operation mode of the multi-connected air conditioning system is a refrigeration mode, calculating the refrigeration pipe ring temperature difference of the target indoor unit according to the inlet air temperature of the target indoor unit and the middle temperature of an inner coil, calculating the refrigeration pipe temperature difference of the target indoor unit according to the middle temperature of the inner coil of the target indoor unit and the low-pressure saturation temperature of the outdoor unit, and calculating the refrigeration superheat degree of the target indoor unit according to the outlet temperature of the inner coil of the target indoor unit and the inlet temperature of the inner coil; wherein the operation parameters comprise the refrigeration pipe loop temperature difference, the refrigeration pipe temperature difference and the refrigeration superheat degree.

According to the method for judging the failure of the electronic expansion valve, provided by the embodiment of the invention, under the condition that the current operation mode of the multi-connected air-conditioning system is a refrigeration mode, the refrigeration pipe loop temperature difference of a target indoor unit is calculated according to the air inlet temperature of the target indoor unit and the middle temperature of the inner coil pipe, the refrigeration pipe temperature difference of the target indoor unit is calculated according to the middle temperature of the inner coil pipe of the target indoor unit and the low-pressure saturation temperature of the outdoor unit, and the refrigeration superheat degree of the target indoor unit is calculated according to the outlet temperature of the inner coil pipe of the target indoor unit and the inlet temperature of the inner coil pipe, so that the operation parameter of the target indoor unit at the current moment during refrigeration operation is obtained, and therefore, the multi-connected air-conditioning system can accurately determine whether the electronic expansion valve in the target indoor unit has the failure under the refrigeration mode based on the operation parameter.

In an optional embodiment, the determining whether an electronic expansion valve in the target indoor unit has a fault according to the operation parameters includes:

under the condition that the operation parameters meet a first refrigeration fault judgment condition or a second refrigeration fault judgment condition, controlling an electronic expansion valve in the target indoor unit to reset;

after the electronic expansion valve in the target indoor unit is controlled to reset, if the running parameters of the target indoor unit at the current moment still meet the first refrigeration fault judgment condition or meet the second refrigeration fault judgment condition, determining that the electronic expansion valve in the target indoor unit has a fault;

wherein the first refrigeration failure determination condition includes: the temperature difference of the refrigerating pipe ring is greater than or equal to a first refrigerating temperature threshold value, the temperature difference of the refrigerating pipe is greater than a second refrigerating temperature threshold value, and the refrigerating superheat degree is greater than a third refrigerating temperature threshold value;

the second refrigeration failure determination condition includes: the refrigerating pipe ring temperature difference is greater than or equal to a fourth refrigerating temperature threshold, the refrigerating pipe temperature difference is smaller than a fifth refrigerating temperature threshold, and the refrigerating superheat degree is smaller than a sixth refrigerating temperature threshold.

In the method for determining a fault of an electronic expansion valve provided in an embodiment of the present invention, when an operation parameter meets a first refrigeration fault determination condition or a second refrigeration fault determination condition, an electronic expansion valve in a target indoor unit is controlled to be reset, and then it is determined whether the operation parameter of the target indoor unit at the current time still meets the first refrigeration fault determination condition or the second refrigeration fault determination condition, and if so, it is determined that the electronic expansion valve in the target indoor unit has a fault. When the operation parameters meet certain refrigeration fault judgment conditions, the electronic expansion valve is controlled to reset at first, and then fault judgment is carried out again according to the operation parameters, so that fault misjudgment caused by the conditions of step loss, misoperation and the like of the electronic expansion valve can be avoided, and the fault judgment precision of the electronic expansion valve is improved.

under the condition that the current operation mode of the multi-connected air-conditioning system is a heating mode, acquiring the air inlet temperature and the heating standby opening degree of the target indoor unit, calculating the heating supercooling degree of the target indoor unit according to the high-pressure saturation temperature of the outdoor unit and the inlet temperature of the inner coil of the target indoor unit, and calculating the heating pipe loop temperature difference of the target indoor unit according to the middle temperature of the inner coil of the target indoor unit and the air inlet temperature;

the operation parameters comprise the air inlet temperature, the heating standby opening degree, the heating supercooling degree and the heating pipe ring temperature difference.

According to the electronic expansion valve fault judging method provided by the embodiment of the invention, under the condition that the current operation mode of the multi-connected air-conditioning system is a heating mode, the inlet air temperature and the heating standby opening degree of a target indoor unit are obtained, the heating supercooling degree of the target indoor unit is calculated according to the high-pressure saturation temperature of the outdoor unit and the inlet temperature of the inner coil of the target indoor unit, and the heating pipe ring temperature difference of the target indoor unit is calculated according to the middle temperature of the inner coil of the target indoor unit and the inlet air temperature, so that the operation parameters of the target indoor unit at the current moment in the heating operation are obtained, and therefore, the multi-connected air-conditioning system can accurately determine whether the electronic expansion valve in the target indoor unit has a fault or not under the heating mode on the basis of the operation parameters.

In an optional embodiment, the determining whether there is a fault in an electronic expansion valve in the target indoor unit according to the operation parameters includes:

controlling the electronic expansion valve in the target indoor unit to reset under the condition that the operation parameter meets a first heating fault judgment condition;

after the electronic expansion valve in the target indoor unit is controlled to reset, if the running parameters of the target indoor unit at the current moment still meet the first heating fault judgment condition, determining that the electronic expansion valve in the target indoor unit has a fault;

wherein the first heating fault determination condition includes: the air inlet temperature is greater than or equal to a first heating temperature threshold, the heating supercooling degree is greater than a second heating temperature threshold, the heating standby opening degree is equal to the opening maximum value, and the heating pipe ring temperature difference is less than or equal to a third heating temperature threshold.

In the method for determining a fault of an electronic expansion valve provided in the embodiment of the present invention, when the operation parameter meets the first heating fault determination condition, the electronic expansion valve in the target indoor unit is controlled to reset, and then it is determined again whether the operation parameter of the target indoor unit at the current time still meets the first heating fault determination condition, and if so, it is determined that the electronic expansion valve in the target indoor unit has a fault. When the operation parameters meet the first heating fault judgment condition, the electronic expansion valve is controlled to reset firstly, and then judgment is carried out again according to the operation parameters and the first heating fault judgment condition, so that whether the electronic expansion valve in the target indoor unit has faults or not is finally determined, fault misjudgment caused by the conditions of step loss, misoperation and the like of the electronic expansion valve can be avoided, and the fault judgment precision of the electronic expansion valve is improved.

controlling the electronic expansion valve in the target indoor unit to reset under the condition that the operation parameters meet a second heating fault judgment condition;

after the electronic expansion valve in the target indoor unit is controlled to reset, if the running parameters of the target indoor unit at the current moment still meet the second heating fault judgment condition, determining that the electronic expansion valve in the target indoor unit has a fault;

wherein the second heating fault determination condition includes: the air inlet temperature is less than or equal to a fourth heating temperature threshold, the heating supercooling degree is less than a fifth heating temperature threshold, the heating standby opening degree is equal to an opening minimum value, and the heating pipe ring temperature difference is greater than or equal to a sixth heating temperature threshold.

In the method for determining a fault of an electronic expansion valve provided in the embodiment of the present invention, when the operation parameter meets the second heating fault determination condition, the electronic expansion valve in the target indoor unit is controlled to be reset, and then it is determined again whether the operation parameter of the target indoor unit at the current time still meets the second heating fault determination condition, and if so, it is determined that the electronic expansion valve in the target indoor unit has a fault. When the operation parameters meet the second heating fault judgment condition, the electronic expansion valve is controlled to reset firstly, and then judgment is carried out according to the operation parameters and the second heating fault judgment condition again, so that whether the electronic expansion valve in the target indoor unit has a fault or not is finally determined, fault misjudgment caused by the conditions of step loss, misoperation and the like of the electronic expansion valve can be avoided, and the fault judgment precision of the electronic expansion valve is improved.

In an alternative embodiment, the method further comprises:

and under the condition that the electronic expansion valve in the target indoor unit is judged to have a fault, controlling the target indoor unit to send out fault alarm information.

According to the method for judging the failure of the electronic expansion valve, provided by the embodiment of the invention, the target indoor unit is controlled to send out failure alarm information under the condition that the electronic expansion valve of the target indoor unit is judged to have the failure, so that a user can be timely informed that the electronic expansion valve of the target indoor unit has the failure, and the user can conveniently and timely perform troubleshooting and repair.

In a second aspect, the present invention provides a device for determining a failure of an electronic expansion valve, which is applied to a multi-connected air conditioning system, where the multi-connected air conditioning system includes an outdoor unit and a plurality of indoor units connected to the outdoor unit, and the device includes:

the determining module is used for determining a target indoor unit in a standby state under the condition that the time length for the compressor of the outdoor unit to exit the starting platform reaches the preset time length;

the acquisition module is used for acquiring the operation parameters of the target indoor unit at the current moment according to the current operation mode of the multi-connected air-conditioning system;

and the judging module is used for judging whether the electronic expansion valve in the target indoor unit has a fault according to the operation parameters.

In the electronic expansion valve fault determination device provided by the embodiment of the invention, the determination module can determine the target indoor unit in a standby state when the time length for the compressor of the outdoor unit to exit the starting platform reaches the preset time length, the acquisition module can acquire the operation parameters of the target indoor unit at the current moment according to the current operation mode of the multi-connected air conditioning system, and the determination module can determine whether the electronic expansion valve in the target indoor unit has a fault according to the operation parameters. Whether the electronic expansion valve has a fault or not is determined according to the operation parameters of the target indoor unit under the condition that the time length for the compressor of the outdoor unit to exit the starting platform reaches the preset time length, so that the electronic expansion valve in the multi-connected air-conditioning system can be automatically checked, the manual detection is avoided, the manual labor can be reduced, and the fault detection efficiency is improved.

In a third aspect, the present invention provides a multi-connected air conditioning system comprising a main controller implementing the method according to any one of the foregoing embodiments by executing a computer program.

In a fourth aspect, the present invention provides a computer readable storage medium having stored thereon a computer program which, when executed by a master controller, implements the method according to any one of the preceding embodiments.

Drawings

Fig. 1 is a block schematic diagram of a multi-connected air conditioning system according to an embodiment of the present invention;

FIG. 2 is a schematic block diagram of an outdoor unit;

FIG. 3 is a schematic block diagram of an indoor unit;

fig. 4 is a schematic flow chart illustrating a method for determining a fault of an electronic expansion valve according to an embodiment of the present invention;

FIG. 5 is a schematic flow chart illustrating a method for determining a failure of an electronic expansion valve according to an embodiment of the present invention;

fig. 6 is a schematic flow chart illustrating a method for determining a fault of an electronic expansion valve according to an embodiment of the present invention;

fig. 7 is a schematic flow chart illustrating a method for determining a fault of an electronic expansion valve according to an embodiment of the present invention;

fig. 8 is a functional block diagram of an electronic expansion valve failure determination apparatus according to an embodiment of the present invention.

Description of reference numerals:

10-a multi-connected air conditioning system; 100-outdoor unit; 101-a compressor; 102-oil separation unit; 103-a gas-liquid separator; 104-a four-way valve; 105-a condenser; 110-indoor unit; 111-electronic expansion valve; 112-a heat exchanger; 120-liquid tube; 130-trachea; 200-a determination module; 210-an obtaining module; 220-decision module.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Fig. 1 is a block diagram of a multi-air conditioning system 10 according to an embodiment of the present invention, and referring to fig. 1, the multi-air conditioning system includes an outdoor unit 100 and a plurality of indoor units 110, and the outdoor unit 100 may be connected to the plurality of indoor units 110 through liquid pipes 120 and air pipes 130, respectively.

Alternatively, in the multi-air conditioning system 10, one or more outdoor units 100 may be provided. In the present embodiment, an example in which the multi-connected air conditioning system 10 includes an outdoor unit will be described.

Optionally, the multi-connected air conditioning system 10 further includes a main controller, configured to execute a computer program to implement the method for determining the failure of the electronic expansion valve according to the embodiment of the present invention. In one possible implementation, the main controller may be provided in the outdoor unit 100; in another possible implementation, the main controller may be located in any one of the indoor units 110.

Alternatively, fig. 2 is a block schematic diagram of an outdoor unit 100, and referring to fig. 2, the outdoor unit 100 includes a compressor 101, an oil separating device 102, a gas-liquid separator 103, a four-way valve 104, and a condenser 105.

Wherein the compressor 101 is used for compressing a driving refrigerant in an air conditioning refrigerant circuit; the oil separation device 102 is used for separating lubricating oil in high-pressure steam discharged by the compressor 101 so as to ensure that the device can safely and efficiently operate; the gas-liquid separator 103 is used for protecting the compressor by separating and preserving the refrigerant liquid in the return gas pipe; the four-way valve 104 is used for switching the refrigerant direction between the refrigeration mode and the molding mode; the condenser 105 condenses the high-pressure and high-temperature refrigerant vapor sent from the compressor into a liquid.

Alternatively, at least two pressure detecting devices, such as pressure sensors, etc., may be further provided in the outdoor unit 100, and the pressure detecting devices may be respectively provided at a compressor discharge pipe and a compressor suction pipe of the outdoor unit 100 for respectively obtaining a high pressure and a low pressure of the outdoor unit 100. It is understood that, in the present embodiment, the high pressure and the low pressure of the outdoor unit 100 are the high pressure and the low pressure of the multi-connected air conditioning system.

Optionally, fig. 3 is a block schematic diagram of the indoor unit 110, please refer to fig. 3, in which the indoor unit 110 includes an electronic expansion valve 111 and a heat exchanger 112.

The electronic expansion valve 111 is arranged on the air pipe and the liquid pipe and used for controlling the on-off of the flow of the refrigerant and adjusting the flow; the heat exchanger 112 is used for exchanging heat between indoor air and refrigerant in a pipeline of the air conditioning system.

Alternatively, the heat exchanger 112 includes an inner coil, and a plurality of temperature detecting devices, such as a temperature sensor, may be disposed in the indoor unit 110.

Alternatively, the temperature detecting devices may be respectively disposed at the inlet, the outlet and the middle of the inner coil, and respectively configured to detect the inlet temperature T2A, the outlet temperature T2B and the middle temperature T2 of the inner coil. It can be understood that the inlet temperature T2A, the outlet temperature T2B, and the middle temperature T2 of the inner coil are the refrigerant inlet temperature, the refrigerant middle temperature, and the refrigerant outlet temperature in the indoor unit 110.

Optionally, the temperature detecting device may also be disposed at an air inlet of the indoor unit 110, and is configured to obtain the inlet air temperature T1 of the indoor unit 110. It can be understood that the intake air temperature T1 is the ambient temperature of the indoor unit.

Embodiments of the present invention further provide a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a main controller, can implement the method for determining a fault of an electronic expansion valve provided in an embodiment of the present invention.

Next, taking the main controller installed in the outdoor unit 100 in fig. 1 as an example, the outdoor unit 100 is taken as an execution main body, and the method for determining a failure of an electronic expansion valve according to an embodiment of the present invention is exemplarily described with reference to a flowchart. Specifically, fig. 4 is a schematic flow chart of a method for determining a fault of an electronic expansion valve according to an embodiment of the present invention, please refer to fig. 4, where the method includes:

step 20, determining a target indoor unit in a standby state under the condition that the time length for the compressor of the outdoor unit to exit the starting platform reaches a preset time length;

optionally, the starting platform is a frequency platform on which a compressor operates when the multi-connected air conditioning system is started, and when the compressor operates on the frequency platform, each component in the multi-connected air conditioning system operates according to a preset initial operation condition.

Optionally, when the compressor of the outdoor unit exits the starting platform, the related components in the multi-connected air conditioning system may enter a feedback control stage, and at this time, the operation condition of the multi-connected air conditioning system is substantially in a steady state.

Optionally, the target indoor unit in the standby state is an indoor unit that is not currently subjected to the power-on instruction. It can be understood that, in the multi-connected air conditioning system, when an indoor unit is turned on and operates according to a received turn-on instruction, the outdoor unit connected to the indoor unit is also turned on, and at this time, the indoor unit that does not receive the turn-on instruction in the multi-connected air conditioning system is the target indoor unit in the standby state.

Optionally, the preset time period may be set in advance according to the actual operation condition and the relevant parameters of the air conditioner. In one possible implementation, the preset duration may be 10 minutes.

S21, acquiring operation parameters of a target indoor unit at the current moment according to the current operation mode of the multi-connected air-conditioning system;

optionally, the current operating mode includes a cooling mode and a heating mode.

Optionally, the operation parameter of the target indoor unit at the current time may represent an operation condition of the target indoor unit at the current time.

As can be understood, the outdoor unit may obtain the corresponding operation parameters of the target indoor unit at the current time according to the current operation mode of the multi-connected air conditioner.

And S22, judging whether the electronic expansion valve in the target indoor unit has a fault or not according to the operation parameters.

Optionally, since the operation parameter may feed back the operation condition of the target indoor unit at the current time, the outdoor unit may determine whether the electronic expansion valve in the target indoor unit has a fault according to the operation parameter.

Optionally, since a certain difference obviously exists between the operation condition of the target indoor unit when the multi-connected air-conditioning system is in the cooling mode and the operation condition of the target indoor unit when the multi-connected air-conditioning system is in the heating mode, in order to make the fault determination result more accurate, different operation parameters of the target indoor unit can be obtained when the multi-connected air-conditioning system is in the cooling mode and when the multi-connected air-conditioning system is in the heating mode to perform fault determination.

In a possible implementation situation, if the current operation mode of the multi-connected air conditioning system is a cooling mode, the outdoor unit needs to obtain a cooling pipe loop temperature difference, a cooling pipe temperature difference and a cooling superheat degree of the target indoor unit at the current time. It can be understood that, in the case that the current operation mode of the multi-connected air conditioning system is the cooling mode, the operation parameters of the target indoor unit at the current time include a cooling pipe loop temperature difference, a cooling pipe temperature difference, and a cooling superheat degree.

Alternatively, the outdoor unit may calculate the operation parameter by combining a plurality of parameters. Specifically, on the basis of fig. 4, the step S21 may be further obtained according to the following steps:

under the condition that the current operation mode of the multi-connected air-conditioning system is a refrigeration mode, the refrigeration pipe ring temperature difference of the target indoor unit is calculated according to the air inlet temperature of the target indoor unit and the middle temperature of the inner coil pipe, the refrigeration pipe temperature difference of the target indoor unit is calculated according to the middle temperature of the inner coil pipe of the target indoor unit and the low-pressure saturation temperature of the outdoor unit, and the refrigeration superheat degree of the target indoor unit is calculated according to the outlet temperature of the inner coil pipe of the target indoor unit and the inlet temperature of the inner coil pipe.

Optionally, the refrigerant pipe loop temperature difference Δ ac may be the difference between the inlet air temperature T1 of the target indoor unit and the middle temperature T2 of the inner coil, i.e., Δ ac = T1-T2.

Alternatively, the cooling pipe temperature difference Δ Tc may be a difference between the target indoor unit inner coil middle temperature T2 and the outdoor unit low pressure saturation temperature Tps, that is, Δ Tc = T2-Tps.

Alternatively, the low pressure saturation temperature Tps may be determined according to the low pressure of the outdoor unit. In one example, calculation formulas of the low pressure and the low pressure saturation temperature may be stored in advance in the outdoor unit, and thus, when the outdoor unit obtains the low pressure, the low pressure saturation temperature may be obtained according to the calculation formula stored in advance; in another example, each low pressure and the corresponding low pressure saturation temperature may be previously stored in the outdoor unit, and the outdoor unit may search for the corresponding low pressure saturation temperature according to the obtained low pressure.

Alternatively, if the pressure detecting device is not disposed in the outdoor unit, the low pressure of the outdoor unit cannot be obtained, and therefore the low pressure saturation temperature Tps cannot be obtained, and at this time, the low pressure saturation temperature Tps may be replaced by another value, for example, the outdoor unit may obtain the temperature T2 of the middle portion of the inner coil of the indoor unit in the on state in the multi-connected air conditioning system, calculate a weighted average value thereof, and replace the low pressure saturation temperature Tps by the weighted average value.

Alternatively, the cooling superheat SH may be the difference between the target indoor unit's inner coil outlet temperature T2B and inner coil inlet temperature T2A, i.e., SH = T2B-T2A.

Optionally, after obtaining the operation parameters of the target indoor unit at the current time, it may be determined whether the electronic expansion valve of the target indoor unit is faulty according to preset refrigeration fault determination conditions, and in order to avoid a situation of fault omission, the refrigeration fault conditions may include a first refrigeration fault determination condition and a second refrigeration fault determination condition.

In addition, in order to avoid the error judgment of the failure, the outdoor unit may control the electronic expansion valve to perform a reset operation first and then perform a failure judgment again when the outdoor unit determines that the electronic expansion valve may have the failure according to the operation parameters of the target indoor unit at the current time.

It can be understood that, in order to avoid the missing determination and the erroneous determination of the electronic expansion valve, on the basis of fig. 4, fig. 5 is another schematic flow chart of the method for determining the fault of the electronic expansion valve according to the embodiment of the present invention, please refer to fig. 5, and the step S22 may be further implemented by the following steps:

s22-1, controlling the electronic expansion valve in the target indoor unit to reset under the condition that the operation parameter meets the first refrigeration fault judgment condition or meets the second refrigeration fault judgment condition;

in this embodiment, if the operation parameter satisfies any one of the first refrigeration fault determination condition and the second refrigeration fault determination condition, it may be preliminarily determined that the target indoor unit has a fault of the electronic expansion valve, and at this time, in order to eliminate the situation that the fault of the electronic expansion valve is erroneously determined, the outdoor unit may first control the electronic expansion valve in the target indoor unit to reset.

Alternatively, the outdoor unit may send a reset instruction to the electronic expansion valve to instruct the electronic expansion valve to reset in a case where it is determined that the operation parameter satisfies the first refrigeration failure determination condition or the second refrigeration failure determination condition.

Alternatively, the specific number of steps in the reset command may be determined according to the type of the electronic expansion valve, for example, if the electronic expansion valve is a direct-acting type, the reset command may be "500 steps for closing the electronic expansion valve"; if the electronic expansion valve is of deceleration type, the reset command may be "close the electronic expansion valve by 2000 steps".

And S22-2, after the electronic expansion valve in the target indoor unit is controlled to be reset, if the running parameters of the target indoor unit at the current moment still meet the first refrigeration fault judgment condition or meet the second refrigeration fault judgment condition, determining that the electronic expansion valve in the target indoor unit has a fault.

In this embodiment, after the electronic expansion valve of the target indoor unit is controlled to be reset, the outdoor unit may obtain the operation parameters of the target indoor unit at the current time again, that is, calculate the cooling pipe loop temperature difference of the target indoor unit again according to the current intake air temperature of the target indoor unit and the middle temperature of the inner coil pipe, calculate the cooling pipe temperature difference of the target indoor unit according to the current middle temperature of the inner coil pipe of the target indoor unit and the current low-pressure saturation temperature of the outdoor unit, calculate the cooling superheat degree of the target indoor unit according to the current outlet temperature of the inner coil pipe of the target indoor unit and the current inlet temperature of the inner coil pipe, and then judge again whether the obtained operation parameters still satisfy the first cooling fault determination condition or the second cooling fault determination condition.

Alternatively, since the error determination has been eliminated by controlling the electronic expansion valve to reset, if the operating parameter of the target indoor unit at the current time still satisfies the first refrigeration fault determination condition or the second refrigeration fault determination condition, it may be determined that the electronic expansion valve of the target indoor unit has a fault.

Wherein the first refrigeration failure determination condition includes: the temperature difference of the refrigerating pipe ring is greater than or equal to a first refrigerating temperature threshold value, the temperature difference of the refrigerating pipe is greater than a second refrigerating temperature threshold value, and the refrigerating superheat degree is greater than a third refrigerating temperature threshold value; the second refrigeration failure determination condition includes: the temperature difference of the refrigerating pipe ring is more than or equal to a fourth refrigerating temperature threshold value, the temperature difference of the refrigerating pipe is less than a fifth refrigerating temperature threshold value, and the refrigerating superheat degree is less than a sixth refrigerating temperature threshold value.

Optionally, in a case that the multi-connected air conditioning system is in the cooling mode, when a time period for the compressor to exit the starting platform reaches a preset time period, the electronic expansion valve of the target indoor unit in the standby state should be in a closed state, that is, the number of steps of the electronic expansion valve is 0 at this time. Therefore, if the electronic expansion valve in the target indoor unit has no fault, no refrigerant should flow through the target indoor unit at this time, in this case, the inlet air temperature T1 of the target indoor unit should be substantially consistent with the middle temperature T2 of the inner coil, the outlet temperature T2B of the inner coil should be substantially consistent with the inlet temperature T2A of the inner coil, and the difference between the middle temperature T2 of the inner coil and the low-pressure saturation temperature Tps of the outdoor unit should be large.

In one example, if the electronic expansion valve in the target indoor unit has no fault, the difference value between the inlet air temperature T1 of the target indoor unit and the middle temperature T2 of the inner coil pipe, namely the temperature difference delta ac of the refrigerating pipe ring is less than 5 ℃; the difference value of the temperature T2B of the outlet of the inner coil and the temperature T2A of the inlet of the inner coil, namely the refrigerating superheat SH is less than 3 ℃; the difference value between the temperature T2 in the middle of the inner coil and the low-pressure saturation temperature Tps of the outdoor unit, namely the temperature difference delta Tc of the refrigerating pipe is more than 10 ℃.

If the electronic expansion valve in the target indoor unit has a fault, there should be a refrigerant leakage flow condition in the target indoor unit, which may include a condition where only one leakage occurs, i.e., a micro leakage, and a condition where a large degree of leakage exists, i.e., a large leakage.

Aiming at the micro-leakage condition, the inlet air temperature T1 of the target indoor unit and the middle temperature T2 of the inner coil pipe have a certain difference, namely the temperature difference delta ac of the refrigerating pipe ring is larger than or equal to a first refrigerating temperature threshold value; in consideration of stability, the low-pressure saturation temperature Tps of the outdoor unit is generally stable, and at this time, due to a micro-leakage condition, the middle temperature T2 of the inner coil pipe is slightly increased, so that the difference value between the middle temperature T2 of the inner coil pipe and the low-pressure saturation temperature Tps of the outdoor unit, namely the temperature difference Δ Tc of the refrigerating pipe is greater than a second refrigerating temperature threshold value; in addition, because the leaked refrigerant flow is small at this time, the flow is smaller than the heat exchange requirement of the multi-connected air conditioning system, and the refrigerant can be completely evaporated, so that the outlet temperature T2B of the inner coil at this time can be far greater than the inlet temperature T2A of the inner coil, that is, the refrigerating superheat SH can be greater than the third refrigerating temperature threshold.

Optionally, the first refrigeration temperature threshold, the second refrigeration temperature threshold, and the third refrigeration temperature threshold may be set in advance according to an actual situation. In one example, the first refrigeration temperature threshold may be 8 ℃, the second refrigeration temperature threshold may be 10 ℃, and the third refrigeration temperature threshold may be 5 ℃.

It can be understood that, if the temperature difference of the refrigeration pipe ring of the target indoor unit is greater than or equal to the first refrigeration temperature threshold, the temperature difference of the refrigeration pipe is greater than the second refrigeration temperature threshold, and the refrigeration superheat degree is greater than the third refrigeration temperature threshold, the target indoor unit meets the first refrigeration fault determination condition.

For a large leakage condition, the inlet air temperature T1 of the target indoor unit and the middle temperature T2 of the inner coil pipe have a certain difference, namely the temperature difference delta ac of the refrigerating pipe ring is larger than or equal to a fourth refrigerating temperature threshold value; at this time, because a large amount of refrigerant circulates in the target indoor unit, the difference between the middle temperature T2 of the inner coil and the low-pressure saturation temperature Tps is influenced by the on-way pressure drop, that is, the difference between the middle temperature T2 of the inner coil and the low-pressure saturation temperature Tps of the outdoor unit, that is, the temperature difference Δ Tc between the temperatures of the refrigerating pipes is smaller than the fifth refrigerating temperature threshold; in addition, since a large amount of refrigerant flows at this time, the refrigerant cannot be completely evaporated, and therefore, the inner-coil outlet temperature T2B is substantially the same as the inner-coil inlet temperature T2A at this time, that is, the refrigerating superheat SH is smaller than the sixth refrigerating temperature threshold value.

Optionally, the fourth cooling temperature threshold, the fifth cooling temperature threshold, and the sixth cooling temperature threshold may be set in advance according to actual conditions. In one example, the fourth refrigeration temperature threshold may be the same as the first refrigeration temperature threshold, 8 ℃, the fifth refrigeration temperature threshold may be 8 ℃, and the sixth refrigeration temperature threshold may be 2 ℃.

It can be understood that if the temperature difference of the refrigeration pipe ring of the target indoor unit is greater than or equal to the fourth refrigeration temperature threshold, the temperature difference of the refrigeration pipe is less than the fifth refrigeration temperature threshold, and the refrigeration superheat degree is less than the sixth refrigeration temperature threshold, the target indoor unit meets the second refrigeration fault determination condition.

In another possible implementation situation, if the current operation mode of the multi-connected air conditioning system is a heating mode, the outdoor unit needs to obtain the intake air temperature, the heating standby opening, the heating supercooling degree, and the heating pipe loop temperature difference of the target indoor unit at the current time. It can be understood that, in the case that the current operation mode of the multi-connected air conditioning system is the heating mode, the operation parameters of the target indoor unit at the current time include an intake air temperature, a heating standby opening degree, a heating supercooling degree, and a heating pipe loop temperature difference.

under the condition that the current operation mode of the multi-connected air-conditioning system is a heating mode, the air inlet temperature and the heating standby opening degree of a target indoor unit are obtained, the heating supercooling degree of the target indoor unit is calculated according to the high-pressure saturation temperature of the outdoor unit and the inlet temperature of an inner coil of the target indoor unit, and the heating pipe loop temperature difference of the target indoor unit is calculated according to the middle temperature of the inner coil of the target indoor unit and the air inlet temperature.

Alternatively, the intake air temperature T1 and the heating standby opening V of the target indoor unit may be directly collected by the outdoor unit.

Alternatively, the heating supercooling degree SC may be a difference between the high pressure saturation temperature Tpd of the outdoor unit and the inner coil inlet temperature T2A of the target indoor unit, i.e., SC = Tpd-T2A.

Alternatively, the high pressure saturation temperature Tpd may be determined according to the high pressure of the outdoor unit. In one example, calculation formulas of the high pressure and the high pressure saturation temperature may be stored in advance in the outdoor unit, and thus, when the outdoor unit obtains the high pressure, the high pressure saturation temperature may be obtained according to the calculation formula stored in advance; in another example, each high pressure and corresponding high pressure saturation temperature may be stored in the outdoor unit in advance, and the outdoor unit may search for the corresponding high pressure saturation temperature according to the obtained high pressure.

Alternatively, if the pressure detecting device is not installed in the outdoor unit, the high pressure of the outdoor unit cannot be obtained, and thus the high pressure saturation temperature Tpd cannot be obtained, and at this time, the high pressure saturation temperature Tpd may be replaced by another value, for example, the outdoor unit may obtain the middle temperature T2 of the inner coil of the indoor unit in the on state in the multi-connected air conditioning system, calculate the weighted average value thereof, and replace the high pressure saturation temperature Tpd by the weighted average value.

Optionally, the heating pipe loop temperature difference Δ Ah may be a difference between the middle temperature T2 of the inner coil of the target indoor unit and the intake air temperature T1, that is, Δ Ah = T2-T1.

Alternatively, after obtaining the operation parameters of the target indoor unit at the current time, whether the electronic expansion valve of the target indoor unit is in failure or not may be determined according to the preset heating failure determination conditions, and in addition, in consideration of the fact that the outdoor unit may have problems such as step loss, misoperation and the like in the electronic expansion valve, the electronic expansion valve is determined to be in failure by mistake, so in order to avoid the situation of failure determination, the outdoor unit may control the electronic expansion valve to perform a reset operation first and then perform a failure determination again when determining that the electronic expansion valve may have a failure according to the operation parameters of the target indoor unit at the current time.

Alternatively, the heating fault determining condition may include a first heating fault determining condition, on the basis of fig. 4, fig. 6 is another schematic flow chart of the method for determining a fault of an electronic expansion valve according to the embodiment of the present invention, please refer to fig. 6, and step S22 may also be implemented by the following steps:

step S22-3 of the invention, under the condition that the operation parameters meet the first heating fault judgment condition, controlling the electronic expansion valve in the target indoor unit to reset;

in this embodiment, if the operation parameter satisfies the first heating fault determination condition, it may be preliminarily determined that the target indoor unit has an electronic expansion valve fault, and at this time, in order to eliminate the electronic expansion valve fault misdetermination, the outdoor unit may first control the electronic expansion valve in the target indoor unit to reset.

Alternatively, the outdoor unit may transmit a reset instruction to the electronic expansion valve to instruct the electronic expansion valve to reset in a case where it is determined that the operation parameter satisfies the first heating failure determination condition.

Alternatively, the specific number of steps in the reset command may be determined according to the type of the electronic expansion valve, for example, if the electronic expansion valve is of a direct-acting type, the reset command may be "500 steps for closing the electronic expansion valve, and then 2 steps for opening the valve SV"; if the electronic expansion valve is of a deceleration type, the reset command may be "close the electronic expansion valve by 2000 steps, and then open the valve by SV2 steps".

The SV2 is a preset maximum opening degree value at the time of standby for heating of the electronic expansion valve in the target indoor unit. As can be appreciated, the electronic expansion valve is now reset to the maximum standby opening.

Step S22-4, after the electronic expansion valve in the target indoor unit is controlled to be reset, if the running parameters of the target indoor unit at the current moment still meet the first heating fault judgment condition, determining that the electronic expansion valve in the target indoor unit has a fault;

in this embodiment, after the electronic expansion valve of the target indoor unit is controlled to be reset, the outdoor unit may reacquire the operation parameters of the target indoor unit at the current time, that is, reacquire the intake air temperature and the heating standby opening of the target indoor unit, calculate the heating supercooling degree of the target indoor unit according to the high-pressure saturation temperature of the outdoor unit and the inlet temperature of the inner coil of the target indoor unit, calculate the heating pipe loop temperature difference of the target indoor unit according to the middle temperature of the inner coil of the target indoor unit and the intake air temperature, and then judge again whether the reacquired operation parameters still satisfy the first heating fault determination condition.

Alternatively, since the error determination has been eliminated by controlling the electronic expansion valve to reset, if the operating parameter of the target indoor unit at the current time still satisfies the first heating error determination condition, it may be determined that the electronic expansion valve of the target indoor unit has an error.

Wherein the first heating failure determination condition includes: the air inlet temperature is more than or equal to a first heating temperature threshold, the heating supercooling degree is more than a second heating temperature threshold, the heating standby opening degree is equal to the maximum opening degree, and the heating pipe ring temperature difference is less than or equal to a third heating temperature threshold.

Optionally, in a case that the multi-connected air conditioning system is in a heating mode, when a time period for the compressor to exit from the starting platform reaches a preset time period, the electronic expansion valve of the target indoor unit in a standby state should maintain an initial heating standby opening degree, and therefore, if there is no fault in the electronic expansion valve of the target indoor unit, a certain flow of refrigerant in the target indoor unit should be circulated at this time.

In this case, the refrigerant is appropriately condensed at the outlet, the heating supercooling degree SC in the target indoor unit is within a certain temperature range, and the heating standby opening V is between the opening maximum value SV2 and the opening minimum value SV1; in addition, since the refrigerant flow rate is proper at this time, the refrigerant includes two phases, in this case, the middle temperature T2 of the inner coil of the target indoor unit is substantially the same as the high-pressure saturation temperature Tpd of the outdoor unit, and therefore, the value range of the heating pipe loop temperature difference Δ Ah can be determined according to the design temperature range of the high-pressure saturation temperature Tpd and the service temperature range of the intake air temperature T1 of the target indoor unit.

Alternatively, the maximum opening degree value SV2 and the minimum opening degree value SV1 may be set in advance, and the maximum opening degree value and the minimum opening degree value at the time of standby for heating of the electronic expansion valve in the target indoor unit may be set.

In one example, if the electronic expansion valve in the target indoor unit has no fault, the heating supercooling degree SC in the target indoor unit of the target indoor unit is greater than or equal to 3 ℃ and less than or equal to 6 ℃; the heating standby opening V is greater than or equal to an opening minimum value SV1 and less than or equal to an opening maximum value SV2; the design temperature range of the high-pressure saturation temperature Tpd is 45-50 ℃, the use temperature range of the air inlet temperature T1 is 10-30 ℃, and the temperature difference delta Ah of the heating pipe ring should be more than or equal to 12 ℃ on the basis of considering the error.

If the electronic expansion valve in the target indoor unit is faulty, the target indoor unit should have no refrigerant flowing therethrough, an excessively low flow rate, or an excessively high flow rate.

Aiming at the condition that the refrigerant does not circulate or the flow is too small, in order to avoid fault misjudgment caused by too low temperature, the inlet air temperature of the target air conditioner is required to be more than or equal to a first heating temperature threshold value; at the moment, the refrigerant does not flow or the flow is too small, so the refrigerant is excessively condensed, the inlet temperature T2A of the inner coil of the target indoor unit is basically consistent with the inlet air temperature T1 of the target indoor unit, the high-pressure saturation temperature Tpd of the outdoor unit is far higher than the inlet temperature T2A of the inner coil, the heating supercooling degree SC is higher than a second heating temperature threshold, and the heating standby opening V is equal to the maximum opening SV2; in addition, at this time, because the refrigerant does not flow through the target indoor unit or the flow rate is too small, the refrigerant is completely condensed and accumulated in the target indoor unit, the temperature T2 of the middle portion of the inner coil of the target indoor unit is substantially consistent with the intake air temperature T1, and the heating pipe loop temperature difference Δ Ah is smaller than or equal to the third heating temperature threshold.

Alternatively, the first heating temperature threshold may be 15 ℃, the second heating temperature threshold may be 6 ℃, and the third heating temperature threshold may be 5 ℃.

It can be understood that the target indoor unit satisfies the first heating fault determination condition if the inlet air temperature of the target indoor unit is greater than or equal to the first heating temperature threshold, the heating supercooling degree is greater than the second heating temperature threshold, the heating standby opening degree is equal to the minimum opening degree value, and the heating pipe loop temperature difference is less than or equal to the third heating temperature threshold. In this embodiment, if the target indoor unit satisfies the first heating fault determination condition, it indicates that the actual electronic expansion valve of the target indoor unit is too small in opening degree or in a closed state, so that the controller may be reset to the maximum opening degree by controlling the electronic expansion valve to reset, and obtain the operation parameters of the target indoor unit again to perform fault determination.

Alternatively, the heating failure determination condition may further include a second heating failure determination condition, because there may be a case where the refrigerant flow amount is excessively large in the target indoor unit when the electronic expansion valve in the target indoor unit fails.

Specifically, on the basis of fig. 4, fig. 7 is another schematic flow chart of the method for determining a fault of an electronic expansion valve according to an embodiment of the present invention, please refer to fig. 7, where step S22 may be further implemented by:

step S22-5 of the invention, under the condition that the operation parameters meet the second heating fault judgment condition, the electronic expansion valve in the target indoor unit is controlled to reset;

in this embodiment, if the operation parameter satisfies the second heating failure determination condition, it may be preliminarily determined that the target indoor unit has an electronic expansion valve failure, and at this time, in order to eliminate the electronic expansion valve failure misjudgment, the outdoor unit may first control the electronic expansion valve in the target indoor unit to reset.

Alternatively, the outdoor unit may transmit a reset instruction to the electronic expansion valve to instruct the electronic expansion valve to reset in a case where it is determined that the operation parameter satisfies the second heating failure determination condition.

Alternatively, the specific number of steps in the reset command may be determined according to the type of the electronic expansion valve, for example, if the electronic expansion valve is of a direct-acting type, the reset command may be "500 steps for closing the electronic expansion valve, and then 1 step for opening the valve SV"; if the electronic expansion valve is of a deceleration type, the reset command may be "close the electronic expansion valve by 2000 steps, and then open the valve by SV1 steps".

The SV1 is a preset minimum opening degree value at the time of standby for heating of the electronic expansion valve in the target indoor unit. It will be appreciated that the electronic expansion valve is now reset to the minimum standby opening.

Step S22-6, after the electronic expansion valve in the target indoor unit is controlled to be reset, if the running parameters of the target indoor unit at the current moment still meet the second heating fault judgment condition, determining that the electronic expansion valve in the target indoor unit has a fault;

in this embodiment, after controlling the electronic expansion valve of the target indoor unit to reset, the outdoor unit may reacquire the operating parameters of the target indoor unit at the current time, that is, reacquire the intake air temperature and the heating standby opening degree of the target indoor unit, calculate the heating supercooling degree of the target indoor unit according to the high-pressure saturation temperature of the outdoor unit and the inner coil inlet temperature of the target indoor unit, calculate the heating pipe loop temperature difference of the target indoor unit according to the middle temperature of the inner coil of the target indoor unit and the intake air temperature, and then judge again whether the reacquired operating parameters still satisfy the second heating fault determination condition.

Alternatively, since the error determination has been eliminated by controlling the electronic expansion valve to reset, if the operating parameter of the target indoor unit at the current time still satisfies the second heating error determination condition, it may be determined that the electronic expansion valve of the target indoor unit has an error.

Wherein the second heating fault determination condition includes: the air inlet temperature is less than or equal to a fourth heating temperature threshold, the heating supercooling degree is less than a fifth heating temperature threshold, the heating standby opening degree is equal to the minimum opening degree, and the heating pipe ring temperature difference is greater than or equal to a sixth heating temperature threshold.

Optionally, for the case of an excessively large refrigerant flow, in order to avoid fault misjudgment caused by excessively high temperature, the inlet air temperature T1 of the target air conditioner should be less than or equal to a fourth heating temperature threshold; at this time, the refrigerant cannot be completely condensed due to the overlarge refrigerant flow, and the high-pressure saturation temperature Tpd of the outdoor unit is basically consistent with the inner coil inlet temperature T2A of the target indoor unit, so that the heating supercooling degree SC is smaller than a fifth heating temperature threshold, and the heating standby opening V is equal to the minimum opening SV1; in addition, at this time, the refrigerant flow in the target indoor unit is too large, so that the refrigerant is in a two-phase state, the temperature T2 of the middle portion of the inner coil of the target indoor unit is substantially the same as the high-pressure saturation temperature Tpd of the outdoor unit, and the heating pipe loop temperature difference Δ Ah is greater than or equal to the sixth heating temperature threshold.

Alternatively, the fourth heating temperature threshold may be 25 ℃, the fifth heating temperature threshold may be 3 ℃, and the sixth heating temperature threshold may be 12 ℃.

It can be understood that, if the intake air temperature of the target indoor unit is less than or equal to the fourth heating temperature threshold, the heating supercooling degree is less than the fifth heating temperature threshold, the heating standby opening degree is equal to the minimum opening degree, and the heating pipe loop temperature difference is greater than or equal to the sixth heating temperature threshold, the target indoor unit satisfies the second heating fault determination condition.

In this embodiment, if the target indoor unit satisfies the second heating fault determination condition, it indicates that the actual opening of the electronic expansion valve of the target indoor unit is too large, and therefore, the controller may reset to the minimum opening by controlling the electronic expansion valve to reset, and obtain the operation parameters of the target indoor unit again to perform fault determination.

Optionally, in order to ensure the operation safety of the multi-connected air conditioning system without affecting the operation of the multi-connected air conditioning system, a user needs to be timely notified to repair a target indoor unit with a failure of an electronic expansion valve when it is determined that the electronic expansion valve in the target indoor unit has a failure. Specifically, on the basis of fig. 4, the method further includes:

and controlling the target indoor unit to send out fault alarm information under the condition that the electronic expansion valve in the target indoor unit is judged to have faults.

Optionally, the failure alarm message is used to notify a user that the electronic expansion valve in the target indoor unit has a failure.

In one example, each indoor unit may be provided with a fault alarm device, such as a fault indicator lamp, and the outdoor unit may control the fault indicator lamp of the target indoor unit to be turned on to send out fault alarm information if it is determined that the electronic expansion valve in the target indoor unit has a fault.

In order to execute the corresponding steps in the above embodiments and various possible manners, an implementation manner of the electronic expansion valve failure determination apparatus is given below. Further, referring to fig. 8, fig. 8 is a functional block diagram of an electronic expansion valve fault determination apparatus according to an embodiment of the present invention. It should be noted that the basic principle and the technical effects of the electronic expansion valve failure determination apparatus provided in the present embodiment are the same as those of the above embodiments, and for the sake of brief description, no part of the present embodiment is mentioned, and reference may be made to the corresponding contents in the above embodiments. The electronic expansion valve fault determination device includes: a determination module 200, an acquisition module 210, and a decision module 220.

The determining module 200 is configured to determine a target indoor unit in a standby state when a duration that a compressor of an outdoor unit exits a starting platform reaches a preset duration;

it is understood that the determining module 200 can be used to implement the above step S20;

the obtaining module 210 is configured to obtain an operation parameter of a target indoor unit at a current moment according to a current operation mode of the multi-connected air conditioning system;

it is understood that the obtaining module 210 can be used to implement the step S21;

the determining module 220 is configured to determine whether an electronic expansion valve in the target indoor unit has a fault according to the operation parameters.

It is understood that the determining module 220 can be used to implement the step S22.

Optionally, the obtaining module 210 is further configured to, when the current operation mode of the multi-connected air conditioning system is a cooling mode, calculate a cooling pipe loop temperature difference of the target indoor unit according to an intake air temperature of the target indoor unit and a middle temperature of the inner coil, calculate a cooling pipe temperature difference of the target indoor unit according to a middle temperature of the inner coil of the target indoor unit and a low-pressure saturation temperature of the outdoor unit, and calculate a cooling superheat degree of the target indoor unit according to an outlet temperature of the inner coil of the target indoor unit and an inlet temperature of the inner coil; wherein, the operation parameters comprise the temperature difference of the refrigeration pipe ring, the temperature difference of the refrigeration pipe and the refrigeration superheat degree.

Optionally, the determining module 220 is further configured to control the electronic expansion valve in the target indoor unit to reset when the operation parameter meets the first refrigeration fault determining condition or meets the second refrigeration fault determining condition; after the electronic expansion valve in the target indoor unit is controlled to reset, if the running parameters of the target indoor unit at the current moment still meet the first refrigeration fault judgment condition or meet the second refrigeration fault judgment condition, determining that the electronic expansion valve in the target indoor unit has a fault; wherein the first refrigeration failure determination condition includes: the temperature difference of the refrigerating pipe ring is greater than or equal to a first refrigerating temperature threshold value, the temperature difference of the refrigerating pipe is greater than a second refrigerating temperature threshold value, and the refrigerating superheat degree is greater than a third refrigerating temperature threshold value; the second refrigeration failure determination condition includes: the temperature difference of the refrigerating pipe ring is greater than or equal to a fourth refrigerating temperature threshold value, the temperature difference of the refrigerating pipe is less than a fifth refrigerating temperature threshold value, and the refrigerating superheat degree is less than a sixth refrigerating temperature threshold value.

It is understood that the determination module 220 can also be used to implement the above steps S22-1 to S22-2.

Optionally, the obtaining module 210 is further configured to, when the current operation mode of the multi-connected air conditioning system is a heating mode, obtain an air intake temperature and a heating standby opening of a target indoor unit, calculate a heating supercooling degree of the target indoor unit according to a high-pressure saturation temperature of the outdoor unit and an inner coil inlet temperature of the target indoor unit, and calculate a heating pipe loop temperature difference of the target indoor unit according to a middle temperature of an inner coil of the target indoor unit and the air intake temperature; the operation parameters comprise air inlet temperature, heating standby opening, heating supercooling degree and heating pipe ring temperature difference.

Optionally, the determining module 220 is further configured to control the electronic expansion valve in the target indoor unit to reset when the operation parameter meets the first heating fault determining condition; after the electronic expansion valve in the target indoor unit is controlled to reset, if the running parameters of the target indoor unit at the current moment still meet the first heating fault judgment condition, determining that the electronic expansion valve in the target indoor unit has a fault; wherein the first heating failure determination condition includes: the air inlet temperature is more than or equal to a first heating temperature threshold, the heating supercooling degree is more than a second heating temperature threshold, the heating standby opening degree is equal to the opening maximum value, and the heating pipe ring temperature difference is less than or equal to a third heating temperature threshold.

It is understood that the determination module 220 can also be used to implement the above steps S22-3 to S22-4.

Optionally, the determining module 220 is further configured to control the electronic expansion valve in the target indoor unit to reset when the operation parameter meets the second heating fault determining condition; after the electronic expansion valve in the target indoor unit is controlled to reset, if the running parameters of the target indoor unit at the current moment still meet the second heating fault judgment condition, determining that the electronic expansion valve in the target indoor unit has a fault; wherein the second heating fault determination condition includes: the air inlet temperature is less than or equal to a fourth heating temperature threshold, the heating supercooling degree is less than a fifth heating temperature threshold, the heating standby opening degree is equal to the minimum opening degree, and the heating pipe ring temperature difference is greater than or equal to a sixth heating temperature threshold.

It is understood that the determination module 220 can also be used to implement the above-mentioned steps S22-5 to S22-6.

Optionally, the determining module 220 is further configured to, in a case that it is determined that the electronic expansion valve in the target indoor unit has a fault, control the target indoor unit to send out fault alarm information.

According to the electronic expansion valve fault determination device provided by the embodiment of the invention, the determining module can determine the target indoor unit in a standby state under the condition that the time length for the compressor of the outdoor unit to exit from the starting platform reaches the preset time length, the acquiring module can acquire the operating parameters of the target indoor unit at the current moment according to the current operating mode of the multi-connected air-conditioning system, and the determining module can determine whether the electronic expansion valve in the target indoor unit has a fault according to the operating parameters. Whether the electronic expansion valve has a fault or not is determined according to the operation parameters of the target indoor unit under the condition that the time length for the compressor of the outdoor unit to exit the starting platform reaches the preset time length, so that the electronic expansion valve in the multi-connected air-conditioning system can be automatically checked, the manual detection is avoided, the manual labor can be reduced, and the fault detection efficiency is improved.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. The method for judging the faults of the electronic expansion valve is applied to a multi-connected air-conditioning system, wherein the multi-connected air-conditioning system comprises an outdoor unit and a plurality of indoor units connected with the outdoor unit, and the method comprises the following steps: determining a target indoor unit in a standby state under the condition that the time length for the compressor of the outdoor unit to exit the starting platform reaches a preset time length;

2. The method as claimed in claim 1, wherein the obtaining of the operation parameters of the target indoor unit at the current moment according to the current operation mode of the multi-connected air conditioning system comprises:

under the condition that the current operation mode of the multi-connected air-conditioning system is a refrigeration mode, calculating a refrigeration pipe ring temperature difference of the target indoor unit according to the inlet air temperature of the target indoor unit and the middle temperature of an inner coil, calculating a refrigeration pipe temperature difference of the target indoor unit according to the middle temperature of the inner coil of the target indoor unit and the low-pressure saturation temperature of the outdoor unit, and calculating the refrigeration superheat degree of the target indoor unit according to the outlet temperature of the inner coil of the target indoor unit and the inlet temperature of the inner coil;

wherein the operation parameters comprise the refrigeration pipe loop temperature difference, the refrigeration pipe temperature difference and the refrigeration superheat degree.

3. The method of claim 2, wherein said determining whether an electronic expansion valve in the target indoor unit is malfunctioning based on the operational parameters comprises:

controlling the electronic expansion valve in the target indoor unit to reset under the condition that the operation parameter meets a first refrigeration fault judgment condition or a second refrigeration fault judgment condition;

4. The method of claim 1, wherein the obtaining of the operation parameters of the target indoor unit at the current moment according to the current operation mode of the multi-connected air conditioning system comprises:

under the condition that the current operation mode of the multi-connected air-conditioning system is a heating mode, acquiring the air inlet temperature and the heating standby opening degree of the target indoor unit, calculating the heating supercooling degree of the target indoor unit according to the high-pressure saturation temperature of the outdoor unit and the inlet temperature of the inner coil of the target indoor unit, and calculating the heating pipe ring temperature difference of the target indoor unit according to the middle temperature of the inner coil of the target indoor unit and the air inlet temperature; the operation parameters comprise the air inlet temperature, the heating standby opening degree, the heating supercooling degree and the heating pipe ring temperature difference.

5. The method of claim 4, wherein said determining whether an electronic expansion valve in the target indoor unit is malfunctioning based on the operational parameters comprises:

wherein the first heating failure determination condition includes: the air inlet temperature is greater than or equal to a first heating temperature threshold, the heating supercooling degree is greater than a second heating temperature threshold, the heating standby opening degree is equal to the opening maximum value, and the heating pipe ring temperature difference is less than or equal to a third heating temperature threshold.

6. The method of claim 4, wherein said determining whether an electronic expansion valve in the target indoor unit is malfunctioning based on the operational parameters comprises:

wherein the second heating failure determination condition includes: the air inlet temperature is less than or equal to a fourth heating temperature threshold, the heating supercooling degree is less than a fifth heating temperature threshold, the heating standby opening degree is equal to the opening degree minimum value, and the heating pipe ring temperature difference is greater than or equal to a sixth heating temperature threshold.

7. The method of claim 1, further comprising: and controlling the target indoor unit to send out fault alarm information under the condition that the electronic expansion valve in the target indoor unit is judged to have a fault.

8. The utility model provides an electronic expansion valve fault decision maker, its characterized in that is applied to many air conditioning systems, many air conditioning systems include the off-premises station and with many indoor sets that the off-premises station links to each other, the device includes: the determining module is used for determining a target indoor unit in a standby state under the condition that the time length for the compressor of the outdoor unit to exit the starting platform reaches the preset time length;

9. A multi-connected air conditioning system characterized by comprising a main controller implementing the method of any one of claims 1 to 7 by executing a computer program.

10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a master controller, carries out the method according to any one of claims 1-7.