Hysteresis detection device and detection method for electronic expansion valve

Abstract

The application discloses a hysteresis detection device and method of electronic expansion valve, comprising the following detection steps: step S1: origin reset and sealing verification; step S2: forward stroke detection: S21: point-by-point driving increases the opening of the electronic expansion valve; S22: setting the inlet pressure global value Pset of the electronic expansion valve, adjusting the inlet measured pressure value Pmeas of the electronic expansion valve of each pulse detection point to approach the pressure global value Pset; S23: correcting the pulse number of a single pulse point; S24: recording the forward output flow value corresponding to each pulse point; step S3: reverse stroke detection: recording the reverse output flow value corresponding to each pulse point; step S4: according to the forward output flow value and the reverse output flow value corresponding to each pulse point, calculating the hysteresis value of each preset detection pulse point. The application provides a hysteresis detection device and method of electronic expansion valve, and improves the hysteresis detection precision.

Description

Technical Field

[0001] This invention relates to the field of electronic expansion valve testing technology, and more specifically, to a hysteresis detection device and method for electronic expansion valves. Background Technology

[0002] As a core flow control component in refrigeration and air conditioning systems, the hysteresis characteristics of electronic expansion valves directly affect the system's control accuracy and operational stability. Therefore, hysteresis detection is a crucial step in the production and acceptance process of electronic expansion valves. Existing hysteresis detection technologies for electronic expansion valves mostly rely on manual operation or simple open-loop control, which has the following technical shortcomings:

[0003] 1. Pressure differential fluctuations affect detection accuracy: During the detection process, it is difficult to keep the pressure differential between the inlet and outlet of the electronic expansion valve constant. Since the flow rate and pressure differential have a non-linear relationship, pressure differential fluctuations will cause flow measurement deviations, which in turn will affect the accuracy of hysteresis calculation.

[0004] 2. Opening control is prone to step loss: During the process of stepper motor driving electronic expansion valve, the step loss phenomenon is easily caused by factors such as mechanical friction and gear backlash, resulting in a mismatch between the command pulse number and the actual opening degree, and distorted detection data. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hysteresis detection device and method for electronic expansion valves, thereby improving the accuracy of hysteresis detection.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a hysteresis detection method for an electronic expansion valve, comprising the following detection steps: Step S1: Origin reset and seal verification: S11: Fully close the electronic expansion valve; S12: With the electronic expansion valve fully closed, detect the leakage flow rate of the electronic expansion valve. If the leakage flow rate value is qualified, proceed to the next detection step; Step S2: Forward stroke detection: S21: Drive the opening of the electronic expansion valve point by point according to the preset detection pulse points; S22: Set the global inlet pressure value Pset of the electronic expansion valve, and adjust the measured inlet pressure value Pmeas of the electronic expansion valve at each pulse detection point to approach the global pressure value Pset. S23: Correct the number of pulses at each pulse point so that the actual opening of the electronic expansion valve corresponds to the number of pulses at that opening; S24: Record the forward output flow value corresponding to each pulse point after correction; Step S3: Reverse stroke detection: S31: Drive the electronic expansion valve to decrease the opening point by point according to the preset detection pulse points; S32: Repeat steps S22 to S23 and record the reverse output flow value corresponding to each pulse point after correction; Step S4: Calculate the hysteresis value of each preset detection pulse point according to the forward output flow value and reverse output flow value corresponding to each pulse point. If the maximum value of the hysteresis value is less than or equal to the hysteresis value threshold, the detection is qualified; otherwise, it is unqualified.

[0007] Furthermore, with the electronic expansion valve fully closed, a leakage flow threshold for the electronic expansion valve is set. If the measured leakage flow of the electronic expansion valve is less than the leakage flow threshold, subsequent testing is performed.

[0008] Furthermore, in step S22, a pressure regulating valve is installed at the inlet of the electronic expansion valve. The measured pressure value Pmeas is adjusted by adjusting the opening of the pressure regulating valve so that the measured pressure value Pmeas approaches the global pressure value Pset.

[0009] Furthermore, the pressure deviation e = global pressure value Pset - measured pressure value Pmeas, and the formula for calculating the adjustment degree u of the pressure regulating valve opening is: u(k) = K p e(k)+K i +K d Δe, where the proportionality constant K p The value range is 0.5-2, and the integral coefficient K i The value range is 0.01-0.1, and the differential coefficient K d The value range is 0.1-1, e(k) is the pressure deviation at the current pulse point, and K i The cumulative pressure deviation up to the current pulse point is Δe, which is the difference between the pressure deviation at the current pulse point and the pressure deviation at the previous pulse point.

[0010] Furthermore, the global pressure value Pset ranges from 0.4 MPa to 0.6 MPa.

[0011] Furthermore, in step S23, the pulse correction value N_out = N_set + K c (Q_ideal-Q_meas), where N_set is the current pulse input value, Q_ideal is the theoretical flow rate under the current pulse, Q_meas is the measured flow rate under the current pulse, and K... c This is the pulse correction coefficient.

[0012] Furthermore, K c The value range is from 0.2 to 0.3.

[0013] Furthermore, at each pulse point, the flow rate values ​​at multiple sampling time points are collected to obtain the average flow rate value. If the rate of change between the flow rate value at each sampling time point and the average flow rate value is less than the stable threshold ε, then the current forward output flow rate value or reverse output flow rate value is recorded.

[0014] Furthermore, the stability threshold ε ranges from 0.4% to 0.55%.

[0015] The present invention also adopts the following technical solution: a hysteresis detection device for an electronic expansion valve, which uses a hysteresis detection method for an electronic expansion valve for detection. The hysteresis detection device for an electronic expansion valve includes an adjustment component. An air intake component and an exhaust component are respectively connected to both sides of the adjustment component. Gas enters the adjustment component from the air intake component and is discharged from the exhaust component. An electronic expansion valve is installed in the adjustment component. The valve opening is controlled by controlling the input pulse of the electronic expansion valve, thereby controlling the flow rate through the adjustment component.

[0016] In summary, the present invention has the following beneficial effects:

[0017] By maintaining a constant inlet pressure, inlet pressure fluctuations are reduced, thereby controlling the inlet-outlet pressure difference. Combined with an opening correction algorithm to compensate for step loss and friction errors, the actual pulse value corresponding to the opening is obtained, ensuring the accuracy of flow detection and opening control, and thus guaranteeing the accuracy of hysteresis detection. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of Embodiment 1;

[0019] Figure 2 This is a flowchart of Example 2.

[0020] Reference numerals: 1. Intake assembly; 2. Adjustment assembly; 21. Electronic expansion valve; 3. Exhaust assembly; 4. Electrical control plug. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1:

[0023] like Figure 1 As shown, this embodiment discloses a hysteresis detection device for an electronic expansion valve, including an adjustment component 2. The adjustment component 2 is equipped with an electronic expansion valve 21. The valve opening is controlled by controlling the input pulses to the electronic expansion valve 21, thereby controlling the flow rate through the adjustment component 2. The electronic expansion valve 21 is electrically connected to a pulse input device via an electrical control plug 4. Different pulse input values ​​correspond to different valve openings of the electronic expansion valve 21. An intake component 1 and an exhaust component 3 are connected to opposite sides of the adjustment component 2. Nitrogen gas is used for detection. The gas enters the adjustment component 2 from the intake component 1 and exits from the exhaust component 3. A pressure detection device is installed in the pipeline of the intake component 1 to detect the intake pressure, and a flow detection device is installed in the pipeline of the exhaust component 3 to detect the flow rate.

[0024] Specifically, the electronic expansion valve 21 is electrically and piped to the stepper motor driver, pressure regulating valve, mass flow meter, and pressure sensor, ensuring correct wiring and proper pipe sealing. The stepper motor driver uses a two-phase four-wire wiring system. The stepper motor driver is electrically connected to the stepper motor of the electronic expansion valve to drive the opening adjustment of the electronic expansion valve 21. The pressure regulating valve is installed in series in the inlet pipe of the electronic expansion valve (i.e., inlet assembly 1) to regulate the inlet pressure. The mass flow meter is installed in series in the outlet pipe of the electronic expansion valve (i.e., exhaust assembly 3) to collect the outlet medium flow of the electronic expansion valve 21. The pressure sensor is installed inside the inlet assembly 1 (between the pressure regulating valve and the inlet of the electronic expansion valve 21) to collect the measured inlet pressure. All pipe connections use sealed joints to prevent medium leakage from affecting the detection.

[0025] Example 2:

[0026] like Figure 2 As shown, a hysteresis detection method for an electronic expansion valve is provided, using the hysteresis detection device for the electronic expansion valve in Embodiment 1.

[0027] The test medium is dry nitrogen. The global pressure value Pset at the inlet of the electronic expansion valve 21 (i.e., the air intake channel of the air intake assembly 1) ranges from 0.4MPa to 0.6MPa. This pressure range is the commonly used inlet pressure for performance testing of expansion valves in the refrigeration and air conditioning industry.

[0028] If the inlet pressure of the electronic expansion valve 21 is too low, the differential pressure will be small, the flow rate will be low, and the signal will be weak, ultimately leading to increased reading errors and affecting hysteresis detection. On the other hand, if the pressure is too high, the requirements for pipeline sealing will increase, the small valve will be easily opened, and the valve core will be unstable, introducing additional errors and hindering detection. Therefore, Pset=0.5MPa is the preferred setting, as the pressure is moderate.

[0029] The exhaust assembly 3 is vented to the atmosphere, and the ambient temperature is controlled at 25±2℃. An ambient temperature sensor is placed in the detection area (close to the electronic expansion valve 21, 5~10cm away from the valve surface) to monitor the ambient temperature in real time and ensure that the detection environment meets the set requirements.

[0030] The inspection method specifically includes the following testing steps:

[0031] Step S1: Origin Reset and Seal Verification:

[0032] S11: Completely close the electronic expansion valve 21.

[0033] The electronic expansion valve 21 is closed to ensure it reaches the mechanical zero position (0 pulses), thus eliminating the stepper motor's accumulated step count error. The detailed process is as follows:

[0034] 1. First, complete the calibration of the total number of steps for the electronic expansion valve 21: Before the test, confirm the rated total number of steps for the electronic expansion valve 21 to be tested (i.e., the total number of stepper motor pulses required to go from the mechanical zero position fully closed to the fully open position, which is 500 pulses in the example) through the equipment manual. If the manual does not specify this, it can be calibrated by pre-test: drive the electronic expansion valve 21 to continuously close the valve from any position until it cannot be rotated, record the number of closing pulses, then continuously open the valve until it cannot be rotated, record the number of opening pulses, and take the average of the two pulse counts as the rated total number of steps;

[0035] 2. The valve closing operation is performed using 1.5 times the total number of steps. Regardless of whether the electronic expansion valve 21 is initially in any position, such as fully open, half open, or close to zero, the valve closing command of 1.5 times the total number of steps can ensure that the valve still has a redundant stroke of at least 0.5 times the total number of steps after passing the zero position. This avoids the valve not closing properly due to unknown initial position or loss of steps, and ensures that the valve is driven to the mechanical limit position (i.e., mechanical zero position).

[0036] 3. After the valve closing action is completed, current feedback is used for verification. A stepper motor current sensor (installed on the power supply line between the stepper motor driver and the stepper motor) is used to collect the motor operating current. When the stepper motor drives the valve to close to the mechanical zero position, the valve touches the mechanical limit, and the rotation resistance increases sharply, causing the stepper motor operating current to rise. When the motor current is detected to reach the preset threshold (1.2 to 1.5 times higher than the normal operating current) and lasts for more than 2 seconds, it is determined that the valve has reached the mechanical limit (zero position), thereby ensuring that the valve accurately reaches the mechanical zero position (0 pulse), completely eliminating the cumulative step error of the stepper motor, and laying the benchmark for subsequent opening control and flow detection.

[0037] S12: With the electronic expansion valve 21 fully closed, detect the leakage flow of the electronic expansion valve 21. If the leakage flow value is qualified, proceed to the next detection step.

[0038] The leakage flow threshold of the electronic expansion valve 21 is set to 250 mL / min to 320 mL / min. Specifically, the threshold is a point value, and its range is from 250 mL / min to 320 mL / min. If the measured leakage flow of the electronic expansion valve 21 is less than the leakage flow threshold, subsequent testing will be performed.

[0039] Step S2: Forward travel detection:

[0040] S21: Preset detection pulse points (e.g., 0, 50, 100, 150...500). Based on the preset detection pulse points, the opening of the electronic expansion valve 21 is driven point by point, and the opening gradually increases (forward detection).

[0041] S22: Adjust the measured inlet pressure value Pmeas of the electronic expansion valve 21 at each pulse detection point to be close to the global pressure value Pset.

[0042] Specifically, the measured pressure Pmeas at the inlet of the electronic expansion valve 21 is collected in real time, and the pressure deviation e = Pset - Pmeas is calculated. The opening adjustment degree of the pressure stabilizing valve used to adjust the inlet pressure of the electronic expansion valve 21 is u, and through the formula u(k)=K p e(k)+K i +K d Δe, where the proportional coefficient K p ranges from 0.5 to 2, the integral coefficient K i ranges from 0.01 to 0.1, the differential coefficient K d ranges from 0.1 to 1, e(k) is the pressure deviation at the current pulse point, K i is the cumulative pressure deviation up to the current pulse point, is the number of bits at the pulse detection point, with values of 1, 2, 3, 4...k, and Δe is the difference between the pressure deviation at the current pulse point and the pressure deviation at the previous pulse point, that is, Δe is equal to the pressure deviation at the current pulse point minus the pressure deviation at the previous pulse point. The opening of the current pressure stabilizing valve body is adjusted according to the obtained u(k) value.

[0043] The opening of the valve body is inversely proportional to the medium flow resistance. When the opening increases, the medium flow resistance decreases, and the medium of the constant pressure source can flow into the inlet side more smoothly. On the premise that the volume of the inlet pipeline is fixed, the medium accumulation amount increases, thereby increasing the inlet pressure; conversely, when the opening decreases, the inlet pressure decreases, so as to achieve the regulation of the inlet pressure.

[0044] At the same time, in the formula, u is the opening adjustment amount of the pressure stabilizing valve, and its numerical change directly corresponds to the change magnitude of the opening of the pressure stabilizing valve. When u increases, the opening of the pressure stabilizing valve increases, and when u decreases, the opening of the pressure stabilizing valve decreases. Through the dynamic adjustment of u, the stable control of the inlet pressure is achieved. Among them, the numerical value of u is linearly and positively correlated with the change of the opening of the pressure stabilizing valve. For every 1 unit increase in the u value, the opening of the pressure stabilizing valve increases by a fixed proportion (such as the opening increases by 1%), and for every 1 unit decrease in the u value, the opening of the pressure stabilizing valve decreases by the corresponding proportion. When Pmeas < Pset, the pressure deviation e is positive, and the u value increases synchronously, and the increasing amplitude is jointly determined by the three parameters K p 、K i 、K d .

[0045] The proportional term K p e(k) determines the basic adjustment amplitude of u (the greater the deviation, the more u increases), and the integral term K i continuously accumulates the deviation, the cumulative value of which can reflect the change direction of the deviation, K i The measured pressure value Pmeas is used to fine-tune the pressure value Pset to approximate the global pressure value, and to correct the u value based on the overall trend of change.

[0046] Differential term K d Δe is used to predict short-term pressure change trends and to correct the u value based on short-term trends, thereby accelerating the correction of the u value.

[0047] When the inlet pressure value Pmeas fluctuates within ≤ ±0.001MPa for n consecutive sampling cycles, the pressure deviation e approaches 0. At this point, the u value tends to stabilize (no longer fluctuates significantly). The stabilized u value corresponds to the optimal opening of the pressure regulating valve.

[0048] The effect of parameter K on u-value adjustment: p K i K d Directly affecting the adjustment speed and magnitude of the u value, such as K p As the value of u increases, the adjustment range of the deviation increases, and the response speed increases; K d Increasing K makes the adjustment of the u value smoother and avoids oscillations; i Increasing the value of u enhances its cumulative regulatory effect, enabling rapid elimination of static deviations and ensuring that the adjustment of the u value is adapted to the pressure control target.

[0049] The u-value is the adjustment amount of the pressure regulating valve opening, not the final opening value. The key difference is that the opening value is the actual opening degree of the pressure regulating valve (a fixed state value), directly reflecting the magnitude of the medium flow resistance; the u-value is a dynamic adjustment command that drives the opening change, fluctuating in real time with the pressure deviation e. By continuously fine-tuning the u-value, the pressure regulating valve opening is brought to and maintained in the optimal state for pressure control, ensuring stable inlet pressure. The reason for achieving stable inlet pressure control is that "the flow rate of the electronic expansion valve has a non-linear relationship with the inlet and outlet pressure difference," specifically as follows:

[0050] 1. Ensuring detection accuracy: The core detection target of this embodiment is the hysteresis characteristic of the electronic expansion valve 21. The calculation of the hysteresis value depends on the comparison between the forward measured flow and the reverse measured flow. The output flow of the electronic expansion valve 21 is not only related to its own opening degree (pulse number), but also affected by the pressure difference between the inlet and outlet. If the inlet pressure value fluctuates, it will cause the flow rate under the same opening degree to deviate, which will cause the hysteresis value calculation to be distorted and fail to meet the detection accuracy requirements.

[0051] 2. Ensure the effectiveness of subsequent opening correction algorithm: The opening correction algorithm is based on the characteristic that "under constant pressure difference, the opening of electronic expansion valve 21 is proportional to the flow rate". It compensates for step loss error through flow deviation. If the inlet pressure value is unstable, it will destroy the proportional relationship between opening and flow rate, causing the flow deviation to fail to accurately reflect the degree of step loss. The opening correction will then lose its meaning and will not be able to compensate for the step loss and friction error of the stepper motor.

[0052] Voltage regulation algorithm parameters (K) p K i K d Quick determination method: The "empirical initial value + rapid fine-tuning" method is adopted. First, the empirical initial value (verified in practice and compatible with most electronic expansion valves) is directly used: K p =1.0, K i =0.05, K d =0.5; Observe the inlet pressure fluctuation through the pressure sensor: if the pressure fluctuation is large and the response is slow, only increase K. p (Increase by 0.2 each time until the fluctuation is ≤ ±0.001MPa); if the pressure oscillation is significant, only decrease K. d (Decrease by 0.1 each time until the oscillation disappears); if there is still a slight deviation after the pressure stabilizes, only increase K. i (Add 0.01 each time, no need for excessive adjustment) to quickly confirm parameters.

[0053] S23: Correct the number of pulses at each pulse point so that the actual opening degree of the electronic expansion valve 21 corresponds to the number of pulses at that opening degree.

[0054] The formula for calculating the pulse correction value N_out is: N_out = N_set + K c (Q_ideal-Q_meas), where N_set is the current pulse input value, Q_ideal is the theoretical flow rate under the current pulse, Q_meas is the measured flow rate under the current pulse, and K... c This is the pulse correction coefficient.

[0055] K c The value of K ranges from 0.2 to 0.3. c The calibration method is used to determine the output pulse count. Three different preset pulse points (e.g., 100, 250, and 400 pulses) are selected for the electronic expansion valve. Under constant differential pressure, different output pulse counts are input, and the corresponding measured flow rate Q_meas is recorded using a mass flow meter. Combined with the theoretical flow rate Q_ideal, the result is calculated using the formula K. c = (N_out - N_set) / (Q_ideal - Q_meas) inverse calculation of K c The average of the back-calculated results from the three pulse points is taken as the final K. c This ensures that the loss of synchronization error can be effectively compensated.

[0056] S24: Record the positive output flow rate value Q_f(n) corresponding to each pulse point; the value of the pulse point is the corrected pulse correction value N_out and the corresponding positive output flow rate value Q_f(n).

[0057] Step S3: Reverse travel detection:

[0058] S31: After the forward stroke detection is completed, adjust the opening of the electronic expansion valve 21 to the maximum, in a manner similar to S11, so as to fully open the electronic expansion valve 21.

[0059] According to the preset detection pulse points, the opening of the electronic expansion valve 21 is driven point by point, and the opening gradually decreases to perform reverse stroke detection;

[0060] S32: Repeat steps S22 to S23, and record the reverse output flow value Q_r(n) and the corrected pulse correction value N_out corresponding to each pulse point;

[0061] Step S4: Based on the forward and reverse output flow rates corresponding to each pulse point, calculate the hysteresis value H(n) for each preset detection pulse point. H(n) = (|Q_f(n) - Q_r(n)|) / Q_max) × 100%, where Q_max is the maximum value in the forward output flow rate data (used as a detection benchmark; reverse flow rate data cannot be used), and Q_f(n) and Q_r(n) are the forward and reverse output flow rates, respectively. Based on the obtained H(n) arrays for different detection points, obtain the maximum value H_max of H(n). If H_max ≤ hysteresis threshold, the hysteresis is acceptable. The hysteresis threshold is set to 2%.

[0062] In step S23, at each pulse point, flow rates at multiple sampling time points are collected to obtain an average flow rate. If the rate of change between the flow rate at each sampling time point and the average flow rate is less than a stability threshold ε, the current forward or reverse output flow rate is recorded. The stability threshold ε ranges from 0.4% to 0.55%.

[0063] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for detecting hysteresis in an electronic expansion valve, characterized in that, The testing steps include the following: Step S1: Origin Reset and Seal Verification: S11: Completely close the electronic expansion valve; S12: With the electronic expansion valve fully closed, detect the leakage flow of the electronic expansion valve. If the leakage flow value is qualified, proceed to the next detection step. Step S2: Forward travel detection: S21: Based on the preset detection pulse points, drive the opening of the electronic expansion valve to increase point by point; S22: Set the global inlet pressure value Pset of the electronic expansion valve, and adjust the measured inlet pressure value Pmeas of the electronic expansion valve at each pulse detection point to be close to the global pressure value Pset; S23: Correct the number of pulses at each pulse point so that the actual opening of the electronic expansion valve corresponds to the number of pulses at that opening; S24: Record the positive output flow rate value corresponding to each corrected pulse point; Step S3: Reverse travel detection: S31: Based on the preset detection pulse points, drive the opening of the electronic expansion valve to decrease point by point; S32: Repeat steps S22 to S23 and record the reverse output flow rate value corresponding to each corrected pulse point; Step S4: Calculate the hysteresis value of each preset detection pulse point based on the forward and reverse output flow values ​​corresponding to each pulse point. If the maximum value of the hysteresis value is less than or equal to the hysteresis value threshold, the detection is qualified; otherwise, it is unqualified.

2. The hysteresis detection method for an electronic expansion valve according to claim 1, characterized in that, With the electronic expansion valve fully closed, a leakage flow threshold for the electronic expansion valve is set. If the measured leakage flow of the electronic expansion valve is less than the leakage flow threshold, subsequent testing is performed.

3. The hysteresis detection method for an electronic expansion valve according to claim 1, characterized in that, In step S22, a pressure regulating valve is installed at the inlet of the electronic expansion valve. The measured pressure value Pmeas is adjusted by adjusting the opening of the pressure regulating valve so that the measured pressure value Pmeas approaches the global pressure value Pset.

4. The hysteresis detection method for an electronic expansion valve according to claim 3, characterized in that, Pressure deviation e = global pressure value Pset - measured pressure value Pmeas. The formula for calculating the adjustment degree u of the pressure regulating valve opening is: u(k) = K p e(k)+K i +K d Δe, where the proportionality constant K p The value range is 0.5-2, and the integral coefficient K i The value range is 0.01-0.1, and the differential coefficient K d The value range is 0.1-1, e(k) is the pressure deviation at the current pulse point, and K i The cumulative pressure deviation up to the current pulse point is Δe, which is the difference between the pressure deviation at the current pulse point and the pressure deviation at the previous pulse point.

5. The hysteresis detection method for an electronic expansion valve according to claim 1, characterized in that, The global pressure value Pset ranges from 0.4 MPa to 0.6 MPa.

6. The hysteresis detection method for an electronic expansion valve according to claim 1, characterized in that, In step S23, the pulse correction value N_out = N_set + K c (Q_ideal-Q_meas), where N_set is the current pulse input value, Q_ideal is the theoretical flow rate under the current pulse, Q_meas is the measured flow rate under the current pulse, and K... c This is the pulse correction coefficient.

7. The hysteresis detection method for an electronic expansion valve according to claim 6, characterized in that, K c The value range is from 0.2 to 0.

3.

8. The hysteresis detection method for an electronic expansion valve according to claim 1, characterized in that, At each pulse point, the flow rate values ​​at multiple sampling time points are collected to obtain the average flow rate value. If the rate of change between the flow rate value at each sampling time point and the average flow rate value is less than the stable threshold ε, the current forward output flow rate value or reverse output flow rate value is recorded.

9. The hysteresis detection method for an electronic expansion valve according to claim 8, characterized in that, The stability threshold ε ranges from 0.4% to 0.55%.

10. A hysteresis detection device for an electronic expansion valve, comprising using the hysteresis detection method for the electronic expansion valve according to any one of claims 1-9, characterized in that, The hysteresis detection device of the electronic expansion valve includes an adjustment component (2). An intake component (1) and an exhaust component (3) are respectively connected to both sides of the adjustment component (2). Gas enters the adjustment component (2) from the intake component (1) and is discharged from the exhaust component (3). The electronic expansion valve is installed on the adjustment component (2). The valve opening is controlled by controlling the input pulse of the electronic expansion valve, thereby controlling the flow rate through the adjustment component (2).

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