Fault detection method, fault detection apparatus, computer device, and storage medium

Abstract

Disclosed in the present application are a fault detection method, a fault detection apparatus, a computer device, and a storage medium. The method comprises: on the basis of the opening degree of a flow control apparatus and a preset mapping function, calculating a first flow coefficient; on the basis of a first operating parameter of the flow control apparatus and a second operating parameter of a compressor, calculating a second flow coefficient; and on the basis of a deviation between the first flow coefficient and the second flow coefficient, performing fault detection on the flow control apparatus, so as to determine a fault detection result. By comparing a flow coefficient, which is obtained by means of real-time detection, with a theoretical flow coefficient to obtain a deviation therebetween, fault detection can be performed on a flow control apparatus in a timely manner, which is conducive to avoiding the impact of a faulty component in a timely manner, thereby improving the stability and reliability of an air conditioning system.

Description

Fault detection methods, fault detection devices, computer equipment and storage media

[0001] This application claims priority to Chinese Patent Application No. 2024105638811, filed on May 8, 2024, entitled "Fault Detection Method, Fault Detection Device, Computer Equipment and Storage Medium", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of fault detection technology, and in particular to a fault detection method, a fault detection device, a computer device, and a non-volatile computer-readable storage medium. Background Technology

[0003] Currently, most air conditioners are equipped with pressure and temperature protection values. When an abnormality is detected in the air conditioner's pressure or temperature, the system will shut down.

[0004] However, fault detection by detecting temperature anomalies has a certain lag and cannot detect faults in a timely manner. When temperature anomalies occur, air conditioner components (such as compressors and heat exchangers) may already be damaged, thus affecting the lifespan of the air conditioner. Summary of the Invention

[0005] This application provides a fault detection method, a fault detection device, a computer device, and a non-volatile computer-readable storage medium. Based on real-time acquired operating parameters (such as real-time opening degree, real-time operating parameters of the flow control device and the compressor), the theoretical flow coefficient and the real-time flow coefficient can be calculated in a timely manner. Based on the deviation between the theoretical flow coefficient and the real-time flow coefficient, the flow control device can be detected in a timely manner, which helps to avoid the impact of faulty components and thus improve the life of electrical appliances (such as air conditioners).

[0006] The fault detection method provided in this application includes: calculating a first flow coefficient based on the opening degree of the flow control device and a preset mapping function; calculating a second flow coefficient based on a first operating parameter of the flow control device and a second operating parameter of the compressor; and performing fault detection on the flow control device based on the deviation between the first flow coefficient and the second flow coefficient to determine the fault detection result.

[0007] In some embodiments, the first operating parameters include the inlet temperature and outlet temperature of the flow control device, and the second operating parameters include the real-time frequency of the compressor, the real-time discharge pressure at the compressor's discharge port, and the real-time return pressure at the compressor's return port. Based on the first operating parameters of the flow control device and the second operating parameters of the compressor, a second flow coefficient is calculated, including: determining the flow rate of the flow control device based on the real-time frequency, real-time discharge pressure, and real-time return pressure; performing pressure conversion on the real-time discharge pressure and real-time return pressure based on the flow rate to obtain the real-time inlet pressure and real-time outlet pressure of the flow control device, respectively; and calculating the second flow coefficient based on the flow rate, inlet temperature, outlet temperature, real-time inlet pressure, and real-time outlet pressure.

[0008] In some embodiments, based on the flow rate, the real-time exhaust pressure and the real-time return pressure are respectively converted into pressure to obtain the real-time inlet pressure and the real-time outlet pressure of the flow control device, including: determining a first pressure difference based on the flow rate and a preset first pressure drop function, wherein the first pressure drop function is a mapping function between the pressure difference between the exhaust pressure and the inlet pressure and the flow rate; determining the real-time inlet pressure based on the first pressure difference and the real-time exhaust pressure; determining a second pressure difference based on the flow rate and a preset second pressure drop function, wherein the second pressure drop function is a mapping function between the pressure difference between the return pressure and the outlet pressure and the flow rate; and determining the real-time outlet pressure based on the second pressure difference and the real-time return pressure.

[0009] In some embodiments, fault detection of the flow control device is performed based on the deviation between the first flow coefficient and the second flow coefficient to determine the fault detection result, including: calculating the real-time pressure difference based on the real-time inlet pressure and the real-time outlet pressure; calculating the fluid density based on the inlet temperature and the real-time inlet pressure; and calculating the second flow coefficient based on the flow rate, the real-time pressure difference, and the fluid density.

[0010] In some embodiments, fault detection of the flow control device is performed based on the deviation between the first flow coefficient and the second flow coefficient to determine the fault detection result, including: calculating the deviation rate of the second flow coefficient relative to the first flow coefficient; and performing fault detection of the flow control device based on the deviation rate and a preset threshold to determine the fault detection result.

[0011] In some embodiments, calculating the deviation rate of the second flow coefficient relative to the first flow coefficient includes: calculating the ratio of the second flow coefficient to the first flow coefficient; and determining the deviation rate based on the difference between the ratio and 1.

[0012] In some embodiments, the preset threshold includes a first threshold and a second threshold, the first threshold being greater than 0 and the second threshold being less than 0. Fault detection of the flow control device is performed based on the deviation rate and the preset threshold to determine the fault detection result, including: determining the fault detection result as a flow control device leak when the deviation rate is greater than the first threshold; determining the fault detection result as a flow control device blockage when the deviation rate is less than the second threshold; and determining the fault detection result as normal when the deviation rate is between the second threshold and the first threshold.

[0013] In some embodiments, fault detection of the flow control device is performed based on the deviation rate and a preset threshold to determine the fault detection result, including: when the deviation rate is between a second threshold and a first threshold, incrementing the counter value by 1, adjusting the opening degree of the flow control device, and performing a step of calculating a first flow system based on the opening degree of the flow control device and a preset mapping function; when the counter value is greater than or equal to a preset design value, outputting the fault detection result as normal.

[0014] In some embodiments, fault detection of the flow control device is performed based on the deviation rate and a preset threshold to determine the fault detection result, including: if the deviation rate is greater than a first threshold, and the opening degree of the flow control device is the minimum value of the opening degree range of the flow control device, the fault detection result is determined to be a leakage of the flow control device; if the deviation rate is less than a second threshold, and the opening degree of the flow control device is the maximum value of the opening degree range, the fault detection result is determined to be a blockage of the flow control device.

[0015] In some embodiments, the fault detection method further includes: issuing a warning message if the fault detection result indicates that the flow control device is leaking or blocked.

[0016] In some embodiments, the preset threshold is determined based on the calculation error of the second flow coefficient and a preset safety factor, the safety factor being determined based on the hardware parameters of the flow control device.

[0017] The fault detection device in this application includes a first processing module, a second processing module, and a detection module. The first processing module is used to calculate a first flow coefficient based on the opening degree of the flow control device and a preset mapping function; the second processing module is used to calculate a second flow coefficient based on a first operating parameter of the flow control device and a second operating parameter of the compressor; the detection module is used to perform fault detection on the flow control device based on the deviation between the first flow coefficient and the second flow coefficient to determine the fault detection result.

[0018] The electrical appliance in this application includes a flow control device; a compressor; a processor and a memory, wherein the memory stores a computer program, the computer program is executed by the processor, and the computer program includes instructions for performing the fault detection method of any of the above embodiments.

[0019] In some embodiments, the flow control device includes an electronic expansion valve.

[0020] The fault detection method, fault detection device, computer equipment, and computer-readable storage medium provided in this application calculate the theoretical flow coefficient (i.e., the first flow coefficient) when the flow control device is operating normally by measuring the real-time opening degree of the flow control device; then, by real-time detection of the first operating parameters of the flow control device and the second operating parameters of the compressor, the real-time flow coefficient (i.e., the second flow coefficient) is calculated. Compared to detecting the impact of a fault in the flow control device on the compressor, resulting in abnormal pressure or temperature, which is relatively delayed, the theoretical flow coefficient and real-time flow coefficient can be calculated in a timely manner based on the real-time collected operating parameters (such as real-time opening degree, real-time operating parameters of the flow control device and the compressor). Therefore, based on the deviation between the theoretical flow coefficient and the real-time flow coefficient, the flow control device can be detected in a timely manner, which is beneficial to avoid the impact of faulty components in a timely manner, thereby improving the life of electrical appliances (such as air conditioners).

[0021] Additional aspects and advantages of embodiments of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of embodiments of this application. Attached Figure Description

[0022] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0023] Figure 1 is a schematic diagram of an application scenario of the fault detection method provided in the embodiments of this application;

[0024] Figure 2 is a flowchart illustrating the fault detection method provided in an embodiment of this application;

[0025] Figure 3 is a schematic diagram of a scenario for the fault detection method provided in an embodiment of this application;

[0026] Figure 4 is a flowchart illustrating the fault detection method provided in an embodiment of this application;

[0027] Figure 5 is a flowchart illustrating the fault detection method provided in an embodiment of this application;

[0028] Figure 6 is a flowchart illustrating the fault detection method provided in an embodiment of this application;

[0029] Figure 7 is a flowchart illustrating the fault detection method provided in an embodiment of this application;

[0030] Figure 8 is a flowchart illustrating the fault detection method provided in an embodiment of this application;

[0031] Figure 9 is a schematic diagram of the modules of the fault detection device provided in an embodiment of this application;

[0032] Figure 10 is a schematic diagram of the structure of the electrical appliance provided in an embodiment of this application;

[0033] Figure 11 is a schematic diagram of the connection state between the non-volatile computer-readable storage medium and the processor provided in an embodiment of this application. Detailed Implementation

[0034] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of this application, and should not be construed as limiting the embodiments of this application.

[0035] To facilitate understanding of this application, the following explanations are provided for the terms used in this application:

[0036] 1. The flow coefficient (usually denoted as Cv or Kv) is a dimensionless number used to quantify the flow capacity of a valve, pipe, or other fluid control component. It represents the component's ability to allow fluid to pass through at a given pressure drop. The flow coefficient reflects not only the component's geometry but also the influence of fluid properties (such as density and viscosity) and flow regime (laminar or turbulent) on the flow rate.

[0037] 2. The AHRI 10-Coefficient Model is an important method for evaluating compressor performance. It comprehensively considers factors such as compressor cooling capacity, input power, and efficiency, providing a unified energy efficiency evaluation standard for the compressor industry. This allows compressors from different manufacturers to be compared under the same standard, promoting fair competition and technological progress within the industry.

[0038] The basic principle of this model involves the compressor's intake, compression, and exhaust processes. In specific calculations, it uses ten parameters (the "compressor ten coefficients") to describe the compressor's performance. These parameters include performance parameters such as cooling capacity, energy efficiency ratio, power consumption, and mass flow rate, as well as environmental parameters such as evaporation and condensation temperatures. By calculating these ten coefficients, the compressor's performance can be evaluated relatively accurately.

[0039] Please refer to Figure 2. An embodiment of this application provides a fault detection method applied to an electrical appliance, such as an air conditioner, which includes a flow control device. The fault detection method provided in this application includes the following steps:

[0040] Step 011: Calculate the first flow coefficient based on the opening degree of the flow control device and the preset mapping function;

[0041] In some embodiments, a flow control device is a device used to control the flow rate of a fluid medium. It is widely used in industrial, agricultural, and domestic fields to solve problems such as unstable flow rate and velocity fluctuations during fluid transmission, thereby improving production efficiency and quality of life. Its main function is to stabilize and regulate the fluid's flow rate and velocity, which can be adjusted according to user needs to keep the fluid's flow rate and velocity within a set range. Examples include electronic expansion valves and thermostatic expansion valves.

[0042] In some embodiments, the opening degree of a flow control device refers to the degree to which a valve or regulator in the device is open, which directly affects the flow rate and velocity of the fluid. The opening degree can be adjusted according to actual needs to meet different flow control requirements. For example, in an electronic expansion valve, a stepper motor drives the valve needle to move, and the movement of the valve needle controls the degree of valve opening, i.e., controls the opening degree of the electronic expansion valve.

[0043] In some embodiments, the preset mapping function is based on the flow control device and is used to describe the mapping relationship between the opening degree and the flow coefficient of the flow control device. Based on the preset mapping function, given the opening degree of the flow control device, the flow coefficient of the flow control device corresponding to the given opening degree can be obtained.

[0044] Specifically, the opening degree of the flow control device is one of the important factors affecting the flow coefficient of the flow control device. Assuming other influencing factors remain constant, based on a preset mapping function, inputting the opening degree of the flow control device can output the flow coefficient corresponding to that opening degree, i.e., the first flow coefficient. It can be understood that the first flow coefficient is used to fit the real-time flow coefficient; therefore, the input opening degree is the same as the real-time opening degree that should be applied during actual operation.

[0045] For example, when the real-time opening degree of the flow control device is 50%, the theoretical flow coefficient of the flow control device when the opening degree is 50% can be obtained based on the preset mapping function. That is, the first flow parameter of the flow control device when the opening degree is 50%.

[0046] Step 012: Calculate the second flow coefficient based on the first operating parameters of the flow control device and the second operating parameters of the compressor;

[0047] In some embodiments, the first operating parameter of the flow control device is a series of specific parameters of the flow control device during actual operation. For example, the first operating parameter may include the inlet temperature, outlet temperature, etc. of the flow control device.

[0048] In some embodiments, the second operating parameter of the compressor is a series of specific parameters of the compressor during actual operation. For example, the second operating parameter may include the compressor's operating frequency, discharge pressure, return gas pressure, etc.

[0049] Specifically, calculating the flow coefficient requires obtaining various operating parameters of the flow control device. Some of these parameters may not be directly available and must be obtained indirectly through the operating parameters of other components (such as the compressor). Based on the first operating parameters of the flow control device and the second operating parameters of the compressor, the various parameters required for calculating the flow coefficient of the flow control device are obtained. Then, based on these parameters, the flow coefficient of the flow control device during actual operation is calculated, which is the second flow coefficient.

[0050] For example, the first operating parameters of the flow control device include the inlet temperature, outlet temperature, inlet pressure, and outlet pressure, where the inlet and outlet pressures cannot be obtained directly. The obtained second operating parameters of the compressor include the operating frequency, discharge pressure, and return pressure. By converting the second operating parameters, the inlet and outlet pressures of the flow control device can be obtained, and finally, the real-time flow coefficient of the flow control device, i.e., the second flow coefficient, can be calculated.

[0051] It is understandable that calculating the flow coefficient of a flow control device requires obtaining various parameters. These parameters can be obtained from the first operating parameters of the flow control device and the second operating parameters of the compressor. Ultimately, this achieves the goal of conveniently calculating the real-time flow coefficient of the flow control device based solely on these parameters.

[0052] Referring to Figure 3, in some embodiments, the first operating parameter includes the inlet temperature and outlet temperature of the flow control device, and the second operating parameter includes the real-time frequency of the compressor, the real-time discharge pressure at the compressor's discharge port, and the real-time return pressure at the compressor's return port. Step 012: Based on the first operating parameter of the flow control device and the second operating parameter of the compressor, calculate the second flow coefficient, including the following steps:

[0053] Step 0121: Determine the flow rate of the flow control device based on the real-time frequency, real-time exhaust pressure, and real-time return pressure;

[0054] In some embodiments, the real-time frequency is the real-time operating frequency of the compressor. The operating frequency of the compressor during actual operation may be variable, so it is necessary to obtain the real-time operating frequency of the compressor.

[0055] In some embodiments, flow rate is a physical quantity used to describe the volume or mass of fluid passing through a cross-section per unit time. A flow control device can stably adjust and control the fluid flow rate under specific operating conditions.

[0056] It's understandable that a compressor has an exhaust port and a return port. Real-time exhaust pressure is the actual exhaust pressure at the compressor's exhaust port during operation; this pressure may vary under different operating conditions. Similarly, real-time return pressure is the actual return pressure at the compressor's return port during operation; this pressure may also vary under different operating conditions.

[0057] In some embodiments, the real-time exhaust pressure and real-time return pressure can be measured by using pressure sensors. The exhaust pressure is measured by a first pressure sensor located at the exhaust port, and the return pressure is measured by a second pressure sensor located at the return port.

[0058] Specifically, the AHRI ten-coefficient model is a model used to evaluate compressor performance. It includes ten parameters used to calculate compressor performance parameters such as cooling capacity, energy efficiency ratio, power, and mass flow rate. Based on the compressor's real-time frequency, real-time discharge pressure, and real-time return pressure, combined with the AHRI ten-coefficient model, the flow rate of the flow control device can be determined.

[0059] Step 0122: Based on the flow rate, the real-time exhaust pressure and real-time return pressure are converted into pressures to obtain the real-time inlet pressure and real-time outlet pressure of the flow control device.

[0060] In some embodiments, the real-time inlet pressure of the flow control device is the real-time pressure at the inlet of the flow control device. The inlet of the flow control device is connected to the discharge port of the compressor. The medium discharged from the discharge port of the compressor flows through the condenser and then flows back into the flow control device at the inlet. The real-time outlet pressure of the flow control device is the real-time pressure at the outlet of the flow control device. The outlet of the flow control device is connected to the return port of the compressor. The medium flowing out of the flow control device flows through the evaporator and then flows back to the compressor from the return port.

[0061] Specifically, since the compressor exhaust port is connected to the inlet of the flow control device, there is a pressure change relationship between the exhaust pressure and the inlet pressure. The real-time exhaust pressure can be converted into the real-time inlet pressure of the flow control device. Since the flow control device outlet is connected to the compressor return port, there is a pressure change relationship between the return pressure and the outlet pressure. The real-time return pressure can be converted into the real-time outlet pressure of the flow control device.

[0062] Step 0123: Calculate the second flow coefficient based on the flow rate, inlet temperature, outlet temperature, real-time inlet pressure, and real-time outlet pressure.

[0063] In some embodiments, the inlet temperature is the temperature at the inlet of the flow control device, and the outlet temperature is the temperature at the outlet of the flow control device.

[0064] In some embodiments, a first temperature sensor is provided at the inlet of the flow control device to detect the inlet temperature; and a second temperature sensor is provided at the outlet of the flow control device to detect the outlet temperature.

[0065] Specifically, the parameter data required to calculate the flow coefficient can be obtained based on the flow rate, inlet temperature, outlet temperature, real-time inlet pressure, and real-time outlet pressure, and the second flow coefficient can be calculated based on the obtained parameter data.

[0066] Thus, based on real-time frequency, real-time exhaust pressure, and real-time return pressure, the flow rate of the flow control device is determined using the AHRI ten-coefficient model. Then, based on the flow rate, the real-time exhaust pressure is converted into real-time inlet pressure, and the real-time return pressure is converted into real-time outlet pressure. This yields the parameters required to calculate the second flow coefficient, avoiding the need to add various sensors to obtain these parameters, thereby reducing both system complexity and detection costs.

[0067] Referring to Figure 4, in some embodiments, step 0122: Based on the flow rate, the real-time exhaust pressure and real-time return pressure are converted into pressures to obtain the real-time inlet pressure and real-time outlet pressure of the flow control device, respectively, including the following steps:

[0068] Step 01221: Based on the flow rate and the preset first pressure drop function, determine the first pressure difference. The first pressure drop function is a mapping function between the pressure difference between the exhaust pressure and the inlet pressure and the flow rate.

[0069] In some embodiments, when the medium in the pipeline flows from the exhaust port to the inlet of the flow control device, pressure loss occurs, resulting in the inlet pressure generally being lower than the exhaust pressure. Under constant pipeline operating conditions (e.g., flow rate), the pressure loss is generally fixed. Therefore, a mapping function between the pressure difference and inlet pressure and the flow rate, i.e., the first pressure drop function, can be established experimentally in advance.

[0070] Input the calculated flow rate into the pre-established first pressure drop function, and the corresponding first pressure difference will be output.

[0071] Step 01222: Determine the real-time inlet pressure based on the first pressure difference and the real-time exhaust pressure;

[0072] In some embodiments, the difference between the real-time exhaust pressure and the first pressure difference can be used as the real-time inlet pressure.

[0073] Step 01223: Based on the flow rate and the preset second pressure drop function, determine the second pressure difference. The second pressure drop function is a mapping function between the pressure difference between the return gas pressure and the outlet pressure and the flow rate.

[0074] In some embodiments, when the medium in the pipeline flows from the outlet of the flow control device to the return port, pressure loss occurs, resulting in the return pressure generally being lower than the outlet pressure. Under constant pipeline operating conditions (e.g., flow rate), the pressure loss is generally fixed. Therefore, a mapping function between the pressure difference and flow rate between the outlet pressure and the return pressure, i.e., the second pressure drop function, can be established experimentally in advance.

[0075] By inputting the calculated flow rate into the pre-established second pressure drop function, the corresponding second pressure difference can be output.

[0076] Step 01224: Determine the real-time outlet pressure based on the second pressure difference and the real-time return gas pressure.

[0077] In some embodiments, the sum of the real-time return gas pressure and the second pressure difference can be used as the real-time outlet pressure.

[0078] Since the real-time discharge pressure and return pressure of the compressor can be easily measured, while the inlet and outlet of the flow control device typically do not have pressure sensors and cannot be directly measured, a method is used to obtain the real-time inlet pressure of the flow control device through the real-time discharge pressure and a first pressure drop function, and the real-time outlet pressure of the flow control device through the real-time return pressure and a second pressure drop function. This not only eliminates the need to add pressure sensors to the inlet and outlet of the flow control device, reducing detection costs, but also reduces the complexity of the detection process.

[0079] Referring to Figure 5, in some embodiments, step 0123: calculating the second flow coefficient based on flow rate, inlet temperature, outlet temperature, real-time inlet pressure, and real-time outlet pressure, includes the following steps:

[0080] Step 01231: Calculate the real-time pressure difference based on the real-time inlet pressure and the real-time outlet pressure;

[0081] Step 01232: Calculate the fluid density based on the inlet temperature and real-time inlet pressure;

[0082] Step 01233: Calculate the second flow coefficient based on flow rate, real-time pressure difference, and fluid density.

[0083] It is understandable that the gas pressure changes after passing through the flow control device, and there is a pressure difference between the real-time inlet pressure and the real-time outlet pressure.

[0084] In some embodiments, fluid density refers to the mass of a unit volume of fluid, an important term in physics. Liquids and gases, as fluids, possess some properties that are significantly different from those of solids, and density is one of them. Fluid density is closely related to temperature and pressure. Fluid density generally decreases as temperature increases and generally increases as pressure increases.

[0085] In some embodiments, the flow coefficient is calculated as follows:

[0086] Where Cv is the flow coefficient, Q is the mass flow rate, ρ is the fluid density, and ΔP is the pressure difference between the inlet and outlet pressures.

[0087] Specifically, the real-time pressure difference ΔP of the flow control device can be obtained based on the real-time inlet and outlet pressures, and the fluid density ρ can be calculated based on the inlet temperature and real-time inlet pressure. Therefore, given the parameters in the flow coefficient calculation formula, the real-time flow coefficient of the flow control device can be calculated, which is the second flow coefficient.

[0088] Thus, referring to the calculation method of the flow coefficient, the parameters required for calculating the flow coefficient are obtained in real time, and the second flow coefficient of the flow control device is finally calculated. At this time, the second flow coefficient is the real-time flow coefficient of the flow control device, which can reflect the real-time flow coefficient of the flow control device during actual operation.

[0089] Step 013: Perform fault detection on the flow control device based on the deviation between the first flow coefficient and the second flow coefficient to determine the fault detection result.

[0090] It is understandable that the first flow coefficient reflects the theoretical flow coefficient of the flow control device under normal operating conditions, while the second flow coefficient is the real-time flow coefficient of the flow control device during actual operation.

[0091] Specifically, there may be a deviation between the first flow coefficient and the second flow coefficient. This deviation reflects the difference between the real-time flow coefficient and the theoretical flow coefficient of the flow control device. By detecting the deviation between the real-time and theoretical flow coefficients, it can be determined whether the flow control device has malfunctioned.

[0092] In some embodiments, if the deviation between the real-time flow coefficient and the theoretical flow coefficient is too large, it can be determined that the flow control device has malfunctioned; if the deviation between the real-time flow coefficient and the theoretical flow coefficient is not large, it can be determined that the flow control device has not malfunctioned.

[0093] In some embodiments, the ratio of the absolute value of the difference between the second flow coefficient and the first flow coefficient to the first flow coefficient can be used as the deviation rate. If the deviation rate is greater than a threshold, the fault detection result is considered a fault; otherwise, the fault detection result is considered normal.

[0094] In this way, the real-time flow coefficient of the flow control device during operation and the theoretical flow coefficient of the flow control device at the same opening degree are calculated. By comparing the deviation between the real-time flow coefficient and the theoretical flow coefficient, it is determined whether the flow control device has malfunctioned.

[0095] Since the flow coefficient is used to characterize the flow capacity of a flow control device, the theoretical flow coefficient (i.e., the first flow coefficient) when the flow control device is operating normally is calculated by measuring the real-time opening degree of the flow control device. Then, the real-time flow coefficient (i.e., the second flow coefficient) is calculated by real-time monitoring of the first operating parameter of the flow control device and the second operating parameter of the compressor. Compared to detecting a flow control device malfunction that affects the compressor and causes abnormal pressure or temperature, which is relatively delayed, the theoretical and real-time flow coefficients can be calculated promptly based on real-time collected operating parameters (such as real-time opening degree, and real-time operating parameters of the flow control device and compressor). Therefore, based on the deviation between the theoretical and real-time flow coefficients, timely fault detection of the flow control device is possible, which helps to avoid the impact of faulty components and thus improves the stability and reliability of the air conditioning system.

[0096] Referring to Figure 6, in some embodiments, fault detection of the flow control device is performed based on the deviation between the first flow coefficient and the second flow coefficient to determine the fault detection result, including the following steps:

[0097] Step 0131: Calculate the deviation rate of the second flow coefficient relative to the first flow coefficient;

[0098] Step 0132: Perform fault detection on the flow control device based on the deviation rate and preset threshold to determine the fault detection result.

[0099] In some embodiments, the preset threshold is used to determine the normal deviation rate range of the fault detection result. When the deviation rate between the second flow coefficient and the first flow coefficient is within the preset threshold, it indicates that the fault detection result is normal.

[0100] Specifically, the flow control device can be judged as to whether it has malfunctioned based on the deviation rate and the preset threshold. If the deviation rate is within the preset threshold, it means that no fault has been detected. If the deviation rate is outside the preset threshold, it means that the flow control device has malfunctioned.

[0101] It is understandable that even if the flow control device is operating normally without malfunction, deviations may still exist between the detected real-time flow coefficient and the theoretical flow coefficient due to various calculation errors or tolerances inherent in the flow control device itself. Therefore, by setting a preset threshold, the deviation rate range of the fault results can be determined. In this way, even if calculation errors and tolerances exist, the preset threshold can eliminate the impact of these errors and tolerances, improving the fault tolerance rate of the detection and avoiding false alarms caused by excessively high detection sensitivity.

[0102] In some embodiments, the preset threshold is determined based on the calculation error of the second flow coefficient and a preset safety factor, the safety factor being determined based on the hardware parameters and design conditions of the flow control device.

[0103] It is understandable that some parameters required for calculating the second flow coefficient need to be acquired through data collection. However, due to the inherent accuracy limitations of the sensors, the acquired data will have a certain degree of error, which is generally within acceptable limits. Furthermore, to ensure consistency across different design conditions and production processes, and to reflect the safety of the flow control device under various design conditions, a safety factor can be preset based on the hardware parameters of the flow control device. For example, during the design phase, the electronic expansion valve undergoes more detailed calibration at its large opening, while the calibration at its small opening is more coarse. By comprehensively considering both the calculation error and the preset safety factor of the flow control device, the preset threshold is determined to ensure its accuracy and applicability.

[0104] Referring to Figure 7, in some embodiments, step 0131: calculating the deviation rate of the second flow coefficient relative to the first flow coefficient includes the following steps:

[0105] Step 1311: Calculate the ratio of the second flow coefficient to the first flow coefficient;

[0106] Step 1312: Determine the deviation rate based on the difference between the ratio and 1.

[0107] Specifically, if the second flow coefficient and the first flow coefficient are equal, then their ratio is 1. The deviation rate is represented by subtracting 1 from the ratio of the second flow coefficient to the first flow coefficient, and the deviation rate can be positive or negative. If the second flow coefficient is greater than the first flow coefficient, the deviation rate is positive; if the second flow coefficient is less than the first flow coefficient, the deviation rate is negative. In this way, the deviation rate can intuitively reflect whether the second flow coefficient is larger or smaller than the first flow coefficient, and can determine the degree of deviation.

[0108] Please refer to Figure 8. In some embodiments, the preset threshold includes a first threshold and a second threshold, where the first threshold is greater than 0 and the second threshold is less than 0, i.e., the first threshold is greater than the second threshold. Step 0132: Perform fault detection on the flow control device based on the deviation rate and the preset threshold to determine the fault detection result, including the following steps:

[0109] Step 01321: If the deviation rate is greater than the first threshold, determine the fault detection result as leakage in the flow control device;

[0110] Step 01322: If the deviation rate is less than the second threshold, determine the fault detection result as blockage of the flow control device;

[0111] Step 01323: If the deviation rate is between the second threshold and the first threshold, the fault detection result is determined to be normal.

[0112] Optionally, since the deviation rate is calculated by subtracting 1 from the ratio of the second flow coefficient to the first flow coefficient, and the second flow coefficient may be greater than or less than the first flow coefficient, the preset threshold can be either positive or negative. The first threshold is set to be greater than 0, and the second threshold to be less than 0. The first and second thresholds represent the upper limit and lower limit, respectively, of the allowable flow capacity of the flow control device.

[0113] Specifically, the flow control device's capacity changes when it leaks or becomes blocked. When the flow control device leaks, its flow capacity is increased, and its flow coefficient is higher than normal. When the flow control device is blocked, its flow capacity is suppressed, and its flow coefficient is lower than normal.

[0114] When the second flow coefficient is greater than the first flow coefficient, it indicates that the real-time flow coefficient of the flow control device is greater than the theoretical flow coefficient, meaning the flow capacity of the flow control device is larger than the theoretical flow capacity. In this case, the ratio of the second flow coefficient to the first flow coefficient is greater than 1, and the deviation rate obtained by subtracting 1 from the ratio is greater than 0. If the preset first threshold is greater than 0, and the deviation rate is greater than 0 but not greater than the first threshold, it indicates that the degree of excess flow capacity of the flow control device is within the allowable range, and the fault detection result can be determined as normal. When the deviation rate is greater than 0 and greater than the first threshold, it indicates that the degree of excess flow capacity of the flow control device exceeds the upper limit of the allowable range, and the fault detection result can be determined as a leak in the flow control device.

[0115] When the second flow coefficient is less than the first flow coefficient, it indicates that the real-time flow coefficient of the flow control device is less than the theoretical flow coefficient, meaning the flow capacity of the flow control device is smaller than the theoretical flow capacity. In this case, the ratio of the second flow coefficient to the first flow coefficient is less than 1, and the deviation rate obtained by subtracting 1 from the ratio is less than 0. The preset second threshold is less than 0. If the deviation rate is less than 0 but not less than the second threshold, it indicates that the degree of under-flow capacity of the flow control device is within the allowable range, and the fault detection result can be determined as normal. When the deviation rate is less than 0 and less than the first threshold, it indicates that the degree of under-flow capacity of the flow control device exceeds the allowable range, and the fault detection result can be determined as a blockage in the flow control device.

[0116] Therefore, if the deviation rate of the flow control device is between the second threshold and the first threshold, the fault detection result can be determined to be normal.

[0117] Thus, based on the changes in the flow capacity of the flow control device during leakage and blockage, a first threshold and a second threshold are set to represent the allowable extent to which the flow capacity of the flow control device is too large and too small, respectively. This not only improves the fault detection tolerance but also allows for more accurate determination of the type of fault occurring in the flow control device.

[0118] In some embodiments, step 0132: performing fault detection on the flow control device based on the deviation rate and a preset threshold to determine the fault detection result includes the following steps:

[0119] Step 01324: When the deviation rate is between the second threshold and the first threshold, increment the counter value by 1, adjust the opening degree of the flow control device, and execute step 011 to calculate the first flow system based on the opening degree of the flow control device and the preset mapping function.

[0120] Step 01325: If the counter value is greater than or equal to the pre-designed value, output the fault detection result as normal.

[0121] Each time the deviation rate falls between the second and first thresholds, the counter value is incremented by 1. If the initial counter value is 0, the counter value is 1. Then, the flow control device opening is adjusted (e.g., increased or decreased). Based on the adjusted opening, step 011 is executed. If the deviation rate again falls between the second and first thresholds after the opening adjustment, the counter value is incremented by 1 again, updating to 2. This process continues until the counter value is greater than or equal to the pre-designed value. It is considered that, after multiple opening adjustments and judgments, the number of times the deviation rate falls between the second and first thresholds is greater than the number of times it does not. Therefore, the fault detection result is determined to be normal. This avoids misjudgments of normal fault detection results and improves the accuracy of normal fault detection. The opening size is different each time.

[0122] In some embodiments, step 0132: performing fault detection on the flow control device based on the deviation rate and a preset threshold to determine the fault detection result includes the following steps:

[0123] Step 01326: If the deviation rate is greater than the first threshold, and the opening degree of the flow control device is the minimum value of the opening degree range of the flow control device, the fault detection result is determined to be leakage of the flow control device.

[0124] Step 01327: If the opening degree of the flow control device is the maximum value of the opening degree range when the deviation rate is less than the second threshold, the fault detection result is determined to be that the flow control device is blocked.

[0125] The minimum value within the opening interval represents the minimum opening value of the flow control device, and the maximum value represents the maximum opening value. After obtaining the deviation rate, if the deviation rate is greater than the first threshold, and the flow control device opening is detected to be the minimum value within the opening interval (meaning the flow control device has been adjusted to its minimum opening, i.e., the flow control device is completely closed), then a leak is considered to have occurred in the flow control device. If the flow control device opening is consistently determined to be the minimum value within the opening interval multiple times, and the deviation rate is greater than the first threshold, then a leak is further determined to have occurred in the flow control device, thus avoiding false positives.

[0126] After obtaining the deviation rate, if the deviation rate is less than the second threshold, it is detected that the opening of the flow control device is the maximum value of the opening range, that is, the opening of the flow control device has been adjusted to the maximum opening, i.e. the flow control device is fully open. At this time, it is considered that the flow control device is blocked. If the opening of the flow control device is determined to be the maximum value of the opening range multiple times in a row, and the deviation rate is less than the second threshold, then it is further determined that the flow control device is blocked to avoid false judgment.

[0127] In some embodiments, the above fault detection method further includes the following steps:

[0128] If the fault detection result indicates that the flow control device is leaking or blocked, a warning message will be issued.

[0129] It's understandable that immediately shutting down the system after a fault is detected would prevent the determination of the cause of the fault, which, while protective, hinders subsequent maintenance. Therefore, issuing warning messages upon fault detection not only promptly alerts users or operators but also, by categorizing the fault and setting corresponding warning messages, indicates the type of malfunction. This facilitates timely shutdown to prevent the impact of the fault and aids in subsequent maintenance, thereby improving the stability and reliability of the air conditioning system.

[0130] Referring to Figure 9, to facilitate better implementation of the fault detection method provided in this application embodiment, this application embodiment also provides a fault detection device 10. The fault detection device 10 may include a first processing module 11, a second processing module 12, and a detection module 13. The first processing module 11 is used to calculate a first flow coefficient based on the opening degree of the flow control device and a preset mapping function; the second processing module 12 is used to calculate a second flow coefficient based on a first operating parameter of the flow control device and a second operating parameter of the compressor; the detection module 13 is used to perform fault detection on the flow control device based on the deviation between the first flow coefficient and the second flow coefficient, to determine the fault detection result.

[0131] In some embodiments, the second processing module 12 is further configured to determine the flow rate of the flow control device based on the real-time frequency, real-time exhaust pressure, and real-time return pressure; perform pressure conversion on the real-time exhaust pressure and real-time return pressure based on the flow rate to obtain the real-time inlet pressure and real-time outlet pressure of the flow control device respectively; and calculate the second flow coefficient based on the flow rate, inlet temperature, outlet temperature, real-time inlet pressure, and real-time outlet pressure.

[0132] In some embodiments, the second processing module 12 is further configured to: determine a first pressure difference based on the flow rate and a preset first pressure drop function, wherein the first pressure drop function is a mapping function between the pressure difference between the exhaust pressure and the inlet pressure and the flow rate; determine a real-time inlet pressure based on the first pressure difference and the real-time exhaust pressure; determine a second pressure difference based on the flow rate and a preset second pressure drop function, wherein the second pressure drop function is a mapping function between the pressure difference between the return gas pressure and the outlet pressure and the flow rate; and determine a real-time outlet pressure based on the second pressure difference and the real-time return gas pressure.

[0133] In some embodiments, the second processing module 12 is further configured to calculate the real-time pressure difference based on the real-time inlet pressure and the real-time outlet pressure; calculate the fluid density based on the inlet temperature and the real-time inlet pressure; and calculate the second flow coefficient based on the flow rate, the real-time pressure difference, and the fluid density.

[0134] In some embodiments, the detection module 13 is further configured to calculate the deviation rate of the second flow coefficient relative to the first flow coefficient; and to perform fault detection on the flow control device based on the deviation rate and a preset threshold to determine the fault detection result.

[0135] In some embodiments, the detection module 13 is further configured to calculate the ratio of the second flow coefficient to the first flow coefficient; and determine the deviation rate based on the difference between the ratio and 1.

[0136] In some embodiments, the preset threshold includes a first threshold and a second threshold, the first threshold being greater than 0 and the second threshold being less than 0. The detection module 13 is further configured to determine the fault detection result as a flow control device leak when the deviation rate is greater than the first threshold; determine the fault detection result as a flow control device blockage when the deviation rate is less than the second threshold; and determine the fault detection result as normal when the deviation rate is between the second threshold and the first threshold.

[0137] In some embodiments, the detection module 13 is further configured to increment the counter value by 1, adjust the opening degree of the flow control device, and perform the step of calculating the first flow system based on the opening degree of the flow control device and a preset mapping function when the deviation rate is between the second threshold and the first threshold; and output the fault detection result as normal when the counter value is greater than or equal to the preset design value.

[0138] In some embodiments, the detection module 13 is further configured to determine the fault detection result as flow control device leakage if the opening degree of the flow control device is the minimum value of the opening degree range of the flow control device when the deviation rate is greater than the first threshold; and to determine the fault detection result as flow control device blockage if the opening degree of the flow control device is the maximum value of the opening degree range when the deviation rate is less than the second threshold.

[0139] In some embodiments, the fault detection device 10 further includes an alarm module 14, which is used to issue an alarm message when the fault detection result indicates that the flow control device is leaking or blocked.

[0140] The fault detection device 10 has been described above from the perspective of functional modules, with reference to the accompanying drawings. These functional modules can be implemented in hardware, in software instructions, or in a combination of hardware and software modules. Specifically, the steps of the method embodiments in this application can be completed by integrated logic circuits in the processor's hardware and / or by software instructions. The steps of the method disclosed in this application can be directly manifested as execution by a hardware encoding processor, or execution by a combination of hardware and software modules in the encoding processor. In some embodiments, the software module can reside in a mature storage medium in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps in the above method embodiments.

[0141] Please refer to Figure 10. This application embodiment also provides an electrical appliance 1000, including a flow control device 200, a compressor 300, a processor 400, and a memory 500. The memory stores a computer program, which is executed by the processor. The computer program includes instructions for performing the fault detection method of any of the above embodiments.

[0142] In some embodiments, the appliance 1000 may be a device with cooling or heating functions. For example, an air conditioner, a freezer, and a heater.

[0143] In some embodiments, the flow control device 200 may be an electronic expansion valve.

[0144] Please refer to Figure 11. This application embodiment also provides a computer-readable storage medium 300, on which a computer program 310 is stored. When the computer program 310 is executed by the processor 320, it implements the steps of the fault detection method of any of the above embodiments. For the sake of brevity, it will not be described again here.

[0145] In the description of this specification, the references to terms such as "some embodiments," "in one example," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0146] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order according to the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0147] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A fault detection method, wherein, include: The first flow coefficient is calculated based on the opening degree of the flow control device and the preset mapping function; The second flow coefficient is calculated based on the first operating parameters of the flow control device and the second operating parameters of the compressor. The flow control device is fault detected based on the deviation between the first flow coefficient and the second flow coefficient to determine the fault detection result.

2. The fault detection method according to claim 1, wherein, The first operating parameters include the inlet and outlet temperatures of the flow control device, and the second operating parameters include the real-time frequency of the compressor, the real-time discharge pressure at the compressor's outlet, and the real-time return pressure at the compressor's return port. The calculation of the second flow coefficient based on the first operating parameters of the flow control device and the second operating parameters of the compressor includes: The flow rate of the flow control device is determined based on the real-time frequency, the real-time exhaust pressure, and the real-time return pressure. Based on the flow rate, the real-time exhaust pressure and the real-time return pressure are converted into pressures to obtain the real-time inlet pressure and real-time outlet pressure of the flow control device, respectively. The second flow coefficient is calculated based on the flow rate, the inlet temperature, the outlet temperature, the real-time inlet pressure, and the real-time outlet pressure.

3. The fault detection method according to claim 2, wherein, The step of converting the real-time exhaust pressure and the real-time return pressure based on the flow rate to obtain the real-time inlet pressure and real-time outlet pressure of the flow control device includes: Based on the flow rate and a preset first pressure drop function, a first pressure difference is determined, wherein the first pressure drop function is a mapping function between the pressure difference between the exhaust pressure and the inlet pressure and the flow rate; The real-time inlet pressure is determined based on the first pressure difference and the real-time exhaust pressure; Based on the flow rate and the preset second pressure drop function, a second pressure difference is determined, wherein the second pressure drop function is a mapping function between the pressure difference between the return gas pressure and the outlet pressure and the flow rate; The real-time outlet pressure is determined based on the second pressure difference and the real-time return gas pressure.

4. The fault detection method according to claim 2 or 3, wherein, The calculation of the second flow coefficient based on the flow rate, the inlet temperature, the outlet temperature, the real-time inlet pressure, and the real-time outlet pressure includes: The real-time pressure difference is calculated based on the real-time inlet pressure and the real-time outlet pressure; Calculate the fluid density based on the inlet temperature and the real-time inlet pressure; The second flow coefficient is calculated based on the flow rate, the real-time pressure difference, and the fluid density.

5. The fault detection method according to any one of claims 1-4, wherein, The step of performing fault detection on the flow control device based on the deviation between the first flow coefficient and the second flow coefficient to determine the fault detection result includes: Calculate the deviation rate of the second flow coefficient relative to the first flow coefficient; The flow control device is subjected to fault detection based on the deviation rate and a preset threshold to determine the fault detection result.

6. The fault detection method according to claim 5, wherein, The calculation of the deviation rate of the second flow coefficient relative to the first flow coefficient includes: Calculate the ratio of the second flow coefficient to the first flow coefficient; The deviation rate is determined based on the difference between the ratio and 1.

7. The fault detection method according to claim 6, wherein, The preset threshold includes a first threshold and a second threshold, wherein the first threshold is greater than 0 and the second threshold is less than 0. The step of performing fault detection on the flow control device based on the deviation rate and the preset threshold to determine the fault detection result includes: If the deviation rate is greater than the first threshold, the fault detection result is determined to be a leak in the flow control device; If the deviation rate is less than the second threshold, the fault detection result is determined to be a blockage in the flow control device; If the deviation rate is between the second threshold and the first threshold, the fault detection result is determined to be normal.

8. The fault detection method according to claim 7, wherein, The step of performing fault detection on the flow control device based on the deviation rate and a preset threshold to determine the fault detection result includes: When the deviation rate is between the second threshold and the first threshold, the counter value is incremented by 1, the opening degree of the flow control device is adjusted, and the step of calculating the first flow system based on the opening degree of the flow control device and the preset mapping function is executed. If the counter value is greater than or equal to the pre-designed value, the fault detection result is output as normal.

9. The fault detection method according to claim 7, wherein, The step of performing fault detection on the flow control device based on the deviation rate and a preset threshold to determine the fault detection result includes: If the deviation rate is greater than the first threshold, and the opening degree of the flow control device is the minimum value of the opening degree range of the flow control device, the fault detection result is determined to be leakage of the flow control device. If the deviation rate is less than the second threshold, and the opening degree of the flow control device is the maximum value of the opening degree range, the fault detection result is determined to be that the flow control device is blocked.

10. The fault detection method according to any one of claims 1 to 9, wherein, The method further includes: If the fault detection result indicates that the flow control device is leaking or blocked, a warning message will be issued.

11. The fault detection method according to claim 9, wherein, The preset threshold is determined based on the calculation error of the second flow coefficient and a preset safety factor, which is determined based on the hardware parameters and design conditions of the flow control device.

12. A fault detection device, wherein, The fault detection device includes: The first processing module is used to calculate the first flow coefficient based on the opening degree of the flow control device and a preset mapping function; The second processing module is used to calculate the second flow coefficient based on the first operating parameters of the flow control device and the second operating parameters of the compressor. The detection module is used to perform fault detection on the flow control device based on the deviation between the first flow coefficient and the second flow coefficient, so as to determine the fault detection result.

13. An electrical appliance, wherein, include: Flow control device; compressor; A processor and a memory, wherein the memory stores a computer program, the computer program being executed by the processor, the computer program including instructions for performing the fault detection method according to any one of claims 1 to 11.

14. The electrical appliance according to claim 11, wherein, The flow control device includes an electronic expansion valve.

15. A non-volatile computer-readable storage medium containing a computer program, wherein, When the computer program is executed by the processor, the processor performs the fault detection method according to any one of claims 1-11.

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