Electronic expansion valve calibration method and device, air-cooled chiller and storage medium

Abstract

The present application relates to a method and device for calibrating an electronic expansion valve, an air-cooled chiller, and a storage medium, wherein the method comprises: during the operation of the air-cooled chiller, when an abnormality of the electronic expansion valve in the air-cooled chiller is detected, opening the orifice solenoid valve in the air-cooled chiller, and obtaining a first pressure at the outlet of the electronic expansion valve, and a second pressure at the outlet of the throttling orifice in the air-cooled chiller; controlling the opening of the electronic expansion valve so that a first absolute value of the first pressure and the second pressure is less than a first preset threshold, and displaying a target opening that matches the target instruction; when controlling the opening of the electronic expansion valve from zero to the target opening again, obtaining a second absolute value of the first pressure and the second pressure, and determining whether the electronic expansion valve is successfully calibrated based on a comparison result of the second absolute value and the second preset threshold.

Description

Technical Field

[0001] The present application relates to the field of air-cooled chillers, and in particular to a calibration method and device for an electronic expansion valve, an air-cooled chiller, and a storage medium. Background Art

[0002] In existing air-cooled chillers, electronic expansion valves serve as the primary throttling component. Commonly used large-capacity electronic expansion valves are typically driven by a stepper motor. During startup and shutdown, the valve is impacted by airflow, and motor vibration can cause the valve to fail to reach the desired opening or to close completely. Furthermore, during operation, impact from gaseous refrigerant can prevent the valve from effectively opening or closing. The actual valve opening is inconsistent with the target opening, further leading to abnormal regulation of the entire system. In actual use, this manifests as inaccurate water temperature control on the user side, which can easily lead to faults such as low pressure and oil shortages in the entire unit.

[0003] There is currently no effective solution to the above problems in the prior art. Summary of the Invention

[0004] The present application provides a calibration method and device for an electronic expansion valve, an air-cooled chiller, and a storage medium to solve the problem in the prior art that during the operation of the air-cooled chiller, if there is a gaseous refrigerant impact, the valve body will not be able to be effectively opened or closed, thereby causing the actual opening of the valve body to be inconsistent with the target opening.

[0005] In the first aspect, the present application provides a method for calibrating an electronic expansion valve, comprising: during the operation of an air-cooled chiller, when an abnormality of the electronic expansion valve in the air-cooled chiller is detected, opening the orifice solenoid valve in the air-cooled chiller, and obtaining a first pressure at the outlet of the electronic expansion valve and a second pressure at the outlet of a throttling orifice in the air-cooled chiller, wherein the electronic expansion valve and the throttling orifice are connected in parallel in the air-cooled chiller; controlling the opening of the electronic expansion valve so that a first absolute value of the first pressure and the second pressure is less than a first preset threshold, and displaying a target opening that matches the target instruction, wherein the target opening is the opening required for the electronic expansion valve to make the absolute value of the first pressure and the second pressure less than a first preset threshold; when controlling the opening of the electronic expansion valve from zero to the target opening again, obtaining a second absolute value of the first pressure and the second pressure, and determining whether the electronic expansion valve is successfully calibrated based on the comparison result of the second absolute value and the second preset threshold.

[0006] Optionally, controlling the opening of the electronic expansion valve so that the first absolute value of the first pressure and the second pressure is less than a first preset threshold value includes: when the first pressure is greater than the second pressure and the first absolute value is greater than the first preset threshold value, closing the electronic expansion valve so that the first absolute value is less than the first preset threshold value; when the first pressure is less than the second pressure and the first absolute value is greater than the first preset threshold value, opening the electronic expansion valve so that the first absolute value is less than the first preset threshold value; and maintaining the opening of the electronic expansion valve unchanged when the first pressure is equal to the second pressure.

[0007] Optionally, whether the electronic expansion valve is successfully calibrated is determined based on a comparison result between the second absolute value and a second preset threshold value, including: when the second absolute value is less than or equal to the second preset threshold value, determining that the electronic expansion valve is successfully calibrated; when the second absolute value is greater than the second preset threshold value, determining that the electronic expansion valve has failed in this calibration, and calibrating the electronic expansion valve again.

[0008] Optionally, the method further includes: determining that the electronic expansion valve is abnormal when the number of times the electronic expansion valve is recalibrated exceeds a preset number.

[0009] Optionally, detecting whether the electronic expansion valve in the air-cooled chiller is abnormal includes: detecting the low-pressure change ratio of the compressor suction port in the air-cooled chiller within a first preset time period; when the low-pressure change ratio is less than a third preset threshold, detecting whether the fan frequency increase rate within the first preset time period is greater than or equal to a fourth preset threshold or whether the water temperature drop rate is greater than or equal to a fifth preset threshold; when the fan frequency increase rate within the first preset time period is greater than or equal to the fourth preset threshold or the water temperature drop rate is greater than or equal to the fifth preset threshold, determining that the electronic expansion valve is normal; when the fan frequency increase rate within the first preset time period is less than the fourth preset threshold and the water temperature drop rate is less than the fifth preset threshold, determining that the electronic expansion valve is abnormal.

[0010] Optionally, after the electronic expansion valve is successfully calibrated, the method further includes: after receiving a shutdown command, controlling the bypass solenoid valve in the air-cooled chiller to open; after detecting that the high pressure at the exhaust port of the compressor and the low pressure at the intake port in the air-cooled chiller are balanced, closing the electronic expansion valve and closing the bypass solenoid valve after the electronic expansion valve is closed.

[0011] Optionally, after the air-cooled chiller is shut down, the method further includes: after receiving a startup command, controlling the orifice solenoid valve in the air-cooled chiller to open; after the compressor runs for a second preset time, controlling the main solenoid valve in the air-cooled chiller to open, and controlling the orifice solenoid valve to close after opening the electronic expansion valve to a target opening.

[0012] In a second aspect, the present application provides a calibration device for an electronic expansion valve, comprising: a first processing module, configured to, during operation of an air-cooled chiller, open an orifice solenoid valve in the air-cooled chiller when an abnormality of the electronic expansion valve in the air-cooled chiller is detected, and obtain a first pressure at an outlet of the electronic expansion valve and a second pressure at an outlet of a throttling orifice in the air-cooled chiller, wherein the electronic expansion valve and the throttling orifice are connected in parallel in the air-cooled chiller; a second processing module, configured to control the opening of the electronic expansion valve so that a first absolute value of the first pressure and the second pressure is less than a first preset threshold, and display a target opening that matches a target instruction, wherein the target opening is the opening required for the electronic expansion valve to make the absolute value of the first pressure and the second pressure less than the first preset threshold; and a third processing module, configured to obtain a second absolute value of the first pressure and the second pressure when controlling the opening of the electronic expansion valve from zero to the target opening again, and determine whether the electronic expansion valve is successfully calibrated based on a comparison result of the second absolute value and a second preset threshold.

[0013] In a third aspect, the present application provides an air-cooled chiller, comprising: at least one communication interface; at least one bus connected to the at least one communication interface; at least one processor connected to the at least one bus; and at least one memory connected to the at least one bus, wherein the processor is configured to execute the electronic expansion valve calibration method described in the first aspect of the present application.

[0014] In a fourth aspect, the present application further provides a computer storage medium storing computer executable instructions, wherein the computer executable instructions are used to execute the electronic expansion valve calibration method described in the first aspect of the present application.

[0015] The above technical solution provided by the embodiment of the present application has the following advantages over the prior art: the method provided by the embodiment of the present application, when an abnormality of the electronic expansion valve is detected, will adjust the opening of the electronic expansion valve so that the absolute value of the first pressure at the outlet of the electronic expansion valve and the second pressure at the outlet of the throttling orifice plate in the air-cooled chiller is less than a first preset threshold value. At this time, the opening of the electronic expansion valve can be considered to be the target opening. The target opening is known, so the currently displayed opening can also be set to the target opening. Then the opening of the electronic expansion valve is controlled from zero to the target opening again, and then the second absolute value of the first pressure and the second pressure is obtained again. If the second absolute value is less than the second preset threshold value, it indicates that the correction is successful. Otherwise, multiple corrections are required or it is determined that the electronic expansion valve is faulty. It can be seen that in the embodiment of the present application, after an abnormality occurs in the electronic expansion valve, it can be automatically corrected. After the correction is successful, the actual opening of the valve body can be guaranteed to be consistent with the target opening, thereby ensuring the stable operation of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0018] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0019] Figure 1 A schematic structural diagram of an air-cooled chiller provided in an embodiment of the present application;

[0020] Figure 2 A flowchart of a calibration method for an electronic expansion valve provided in an embodiment of the present application;

[0021] Figure 3 A flow chart of a self-correction control method for an electronic expansion valve provided in an embodiment of the present application;

[0022] Figure 4 A schematic structural diagram of a calibration device for an electronic expansion valve provided in an embodiment of the present application;

[0023] Figure 5A schematic diagram of an optional structure of an air-cooled chiller provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0025] The disclosure below provides many different embodiments or examples for implementing different configurations of the present invention. To simplify the disclosure of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0026] In order to solve the problem in the prior art that during the operation of an air-cooled chiller, if there is a gaseous refrigerant impact, the valve body cannot be effectively opened or closed, thereby causing the actual opening of the valve body to be inconsistent with the target opening, the present application provides an air-cooled chiller, such as Figure 1 As shown, the air-cooled chiller includes: a compressor 1, a water-side heat exchanger 2, an air-cooled fin heat exchanger 3, a system electronic expansion valve 4, a throttling orifice plate 5, a bypass solenoid valve 6, an orifice plate solenoid valve 7, a main line solenoid valve 8, a first one-way valve 9, and a second one-way valve 10.

[0027] based on Figure 1 The present application provides a method for calibrating an electronic expansion valve for an air-cooled chiller. Figure 2 As shown, the steps of the method include:

[0028] Step 201: during operation of the air-cooled chiller, if an abnormality is detected in an electronic expansion valve in the air-cooled chiller, opening an orifice plate solenoid valve in the air-cooled chiller and obtaining a first pressure at an outlet of the electronic expansion valve and a second pressure at an outlet of a throttling orifice plate in the air-cooled chiller, wherein the electronic expansion valve and the throttling orifice plate are connected in parallel in the air-cooled chiller;

[0029] It should be noted that when an abnormality is detected in the electronic expansion valve, the orifice solenoid valve is first opened to prevent blockage of the system flow path and other faults. The electronic expansion valve is then self-adjusted to restore it to normal operation.

[0030] Step 202: Control the opening of the electronic expansion valve so that a first absolute value of the first pressure and the second pressure is less than a first preset threshold, and display a target opening that matches the target instruction, wherein the target opening is the opening required for the electronic expansion valve to make the absolute value of the first pressure and the second pressure less than the first preset threshold;

[0031] In a specific example, the target opening can be set accordingly according to actual needs, but in a specific application scenario, it is preferably set to 50%, and other openings close to 50% are also feasible, such as 49%, 51%, etc.

[0032] Step 203 , when controlling the opening of the electronic expansion valve from zero to the target opening again, obtaining the second absolute value of the first pressure and the second pressure, and determining whether the electronic expansion valve is calibrated successfully based on the comparison result of the second absolute value and the second preset threshold.

[0033] It can be seen from the above steps 201 to 203 that when an abnormality of the electronic expansion valve is detected, the opening of the electronic expansion valve will be adjusted so that the absolute value of the first pressure at the outlet of the electronic expansion valve and the second pressure at the outlet of the throttling orifice plate in the air-cooled chiller is less than the first preset threshold value. At this time, the opening of the electronic expansion valve can be considered to be the target opening. The target opening is known, so the currently displayed opening can also be set to the target opening. Then the opening of the electronic expansion valve is controlled from zero to the target opening again, and then the second absolute value of the first pressure and the second pressure is obtained again. If the second absolute value is less than the second preset threshold value, it indicates that the correction is successful. Otherwise, multiple corrections are required or it is determined that the electronic expansion valve is faulty. It can be seen that in the embodiment of the present application, after the electronic expansion valve has an abnormality, it can be corrected by itself. After the correction is successful, the actual opening of the valve body can be guaranteed to be consistent with the target opening, thereby ensuring the stable operation of the entire system.

[0034] In the embodiment of the present application, the difference between the first pressure and the second pressure can be adjusted by controlling the opening of the electronic expansion valve. Therefore, the method of controlling the opening of the electronic expansion valve involved in step 202 so that the first absolute value of the first pressure and the second pressure is less than the first preset threshold value can further include:

[0035] Step 21: When the first pressure is greater than the second pressure and the first absolute value is greater than a first preset threshold, close the electronic expansion valve so that the first absolute value is less than the first preset threshold;

[0036] Step 22: When the first pressure is less than the second pressure and the first absolute value is greater than a first preset threshold, the electronic expansion valve is opened to make the first absolute value less than the first preset threshold.

[0037] Step 23: When the first pressure is equal to the second pressure, maintain the opening of the electronic expansion valve unchanged.

[0038] For the above steps 21 to 23, combine Figure 1 In a specific example, the following can be done: first open the orifice solenoid valve 7, then compare the pressure P1 (first pressure) after the electronic expansion valve 4 with the pressure P2 (second pressure) after the throttling orifice 5; when P1>P2, close the electronic expansion valve 4; when P1<P2, open the electronic expansion valve 4; when P1=P2, keep the valve stationary; after opening the orifice solenoid valve 7, synchronously calculate the absolute value of P1-P2; when the absolute value is ≤X, stop adjusting the valve.

[0039] It should be noted that the throttling orifice 5 in the embodiment of the present application is designed and selected to match the throttling effect of the 50% opening (target opening) of the electronic expansion valve 4, that is, the pressure after throttling is basically the same. In addition, in the present application, the orifice plate solenoid valve 7 is opened first to avoid blockage of the system flow path and other faults. Because there are differences in detection, it is difficult to keep P1 and P2 completely consistent. Therefore, a capacity value of X is given. X is usually set to 5-10%. It is assumed that the actual opening of the valve at this time is 50%, and the target command and displayed opening at this time are both corrected to 50%; wherein, the target command is the command sent to the air-cooled chiller to control the opening of the electronic expansion valve. That is, the opening of the electronic expansion valve is the same as the opening indicated by the target command, and the displayed opening of the air-cooled chiller is consistent with the opening indicated by the target command.

[0040] Steps 21 to 23 described above are actually self-regulation of the electronic expansion valve. To verify the accuracy of the self-regulation results, it is necessary to further determine whether the difference in outlet pressure between the electronic expansion valve and the throttle orifice plate during actual operation is within a preset range when the electronic expansion valve is opened from zero to the target opening. This indicates that the outlet pressures of the electronic expansion valve and the parallel throttle orifice plate are equivalent, indicating that the electronic expansion valve has returned to normal operation. If the pressure difference is not within the preset range, it may be necessary to self-regulate again or the electronic expansion valve may be deemed to have failed and cannot be corrected through self-regulation. Therefore, the method of determining whether the electronic expansion valve has been successfully calibrated based on the comparison result of the second absolute value and the second preset threshold value involved in step 203 described above can further include:

[0041] Step 31, when the second absolute value is less than or equal to a second preset threshold, determining that the electronic expansion valve calibration is successful;

[0042] Step 32 : When the second absolute value is greater than a second preset threshold, it is determined that the current calibration of the electronic expansion valve has failed, and the electronic expansion valve is calibrated again.

[0043] For the above steps 31 and 32, based on the above steps 21 to 23, Figure 1 The process may be: controlling the valve body from 0 to 50% again, detecting the pressure P1 after the electronic expansion valve 4 and the pressure P2 after the throttling orifice 5 (because the throttling orifice 5 is designed and selected to match, that is, to maintain the same throttling effect as the 50% opening of the electronic expansion valve 4, that is, the pressures after throttling of the two are basically the same), and calculating the absolute value of P1-P2 at the same time. When the absolute value is ≤Ps, where Ps is the throttling pressure comparison value, which is a preset value and is set according to the difference between the throttling orifice and the electronic expansion valve during matching, usually set at 15~30kPa, it is considered that the reset correction is successful, the electronic expansion valve 4 is opened to 100% opening for normal adjustment, and then the orifice solenoid valve 7 is closed; if the absolute value is >Ps, the reset is unsuccessful, and the valve body correction action is repeated.

[0044] In the embodiments of the present application, it is possible that the electronic expansion valve cannot be accurately calibrated through a single calibration, and multiple calibrations may be required. For example, after the first calibration, although the default opening is 50% (the target opening), the actual opening may be 40%, requiring a second calibration. After the calibration, if the default target opening is substantially consistent with the actual opening, the calibration is successful. However, it is also possible that the calibration still fails after several calibrations, in which case it is considered that the electronic expansion valve itself is faulty and cannot self-regulate and recover. Based on this, the method of the embodiments of the present application further includes:

[0045] Step 41 : When the number of times the electronic expansion valve is calibrated again exceeds a preset number, it is determined that the electronic expansion valve is abnormal.

[0046] In this regard, in a specific example, the preset number of times can be set to 3 times, 4 times, etc.

[0047] In the embodiment of the present application, before the self-regulation of the electronic expansion valve, it is first determined whether the electronic expansion valve is abnormal. Based on this, in the embodiment of the present application, the method for detecting whether the electronic expansion valve in the air-cooled chiller is abnormal may include the following steps:

[0048] Step 51, detecting a low pressure change ratio at an air intake of a compressor in an air-cooled chiller within a first preset time period;

[0049] Step 52: If the low pressure change ratio is less than the third preset threshold, detect whether the fan frequency increase rate is greater than or equal to the fourth preset threshold or whether the water temperature decrease rate is greater than or equal to the fifth preset threshold within the first preset time period;

[0050] Step 53: If the fan frequency increase rate is greater than or equal to a fourth preset threshold or the water temperature drop rate is greater than or equal to a fifth preset threshold within the first preset time period, it is determined that the electronic expansion valve is normal;

[0051] Step 54 : When the fan frequency increase rate is less than a fourth preset threshold and the water temperature drop rate is less than a fifth preset threshold within the first preset time period, it is determined that the electronic expansion valve is abnormal.

[0052] In this embodiment of the present application, the first preset duration can be set to within 1-2 minutes. If the duration is too short, the valve body adjustment cycle will not keep up, while if the duration is too long, it will be impossible to clearly distinguish whether the abnormality is caused by system operation or the valve body. In addition, the third preset threshold value can generally be set to 1%-2%.

[0053] Based on this, for the above steps 51 to 54, combined with Figure 1 In a specific example, it can be: during the operation of the unit, the valve body of the electronic expansion valve is opened (the flow area becomes larger). When it is detected that the valve body has a low pressure rise ratio of △P within the time t1, L If the value is less than or equal to m%, then it is determined that opening the valve wider has no significant effect, and further investigation is required to determine whether there is a valve abnormality. If the effect of opening the valve wider on the low pressure is not significant, a simultaneous determination is made as to whether there has been a fan frequency increase or a water temperature decrease during the time period t1. If the fan frequency increase rate is ≥ Δf (the fourth preset threshold) or the water temperature decrease rate is ≥ ΔT (the fifth preset threshold), then it is assumed that the fan or water temperature is the cause, and no correction adjustment is required. If the fan frequency increase rate is not ≥ Δf or the water temperature decrease rate is not ≥ ΔT, then it is determined that the actual valve opening has begun to mismatch the target, and correction adjustment is required.

[0054] In the embodiment of the present application, after the electronic expansion valve is successfully calibrated, it is necessary to level the on / off pressure difference to ensure that the expansion valve is not impacted by airflow when opening and closing, and can be closed and opened stably. Based on this, to prevent airflow impact during shutdown, the embodiment of the present application also includes:

[0055] Step 61, after receiving the shutdown command, controlling the bypass solenoid valve in the air-cooled chiller to open;

[0056] Step 62: After detecting that the high pressure at the exhaust port of the compressor and the low pressure at the intake port of the air-cooled chiller are balanced, close the electronic expansion valve and then close the bypass solenoid valve after the electronic expansion valve is closed.

[0057] In this regard, if the refrigerant passing through the expansion valve is in a gaseous state when the machine is shut down, the airflow impact causes the valve body to shake, making it impossible for the valve to close normally to 0%, which will cause the valve body to be directly out of adjustment when the machine is turned on next time. In this regard, in the embodiment of the present application, when the whole machine receives the shutdown command and the compressor is turned off, the bypass solenoid valve 6 is controlled to open. The bypass solenoid valve 6 is opened to bypass the high and low pressure differences. When the high and low pressure differences remain consistent, the refrigerant inside the system will no longer flow at a high speed, and will not cause impact on the valve body. After detecting that the high pressure at the compressor exhaust port and the low pressure at the intake port are balanced, the electronic expansion valve 4 is closed. After the electronic expansion valve 4 is completely closed, the bypass solenoid valve 6 is closed, thereby avoiding the airflow impact during shutdown.

[0058] Regarding preventing airflow shock during startup, the method in the embodiment of the present application further includes:

[0059] Step 71, after receiving the power-on command, controlling the orifice plate solenoid valve of the air-cooled chiller to open;

[0060] Step 72 : After the compressor runs for a second preset time, the main solenoid valve in the air-cooled chiller is controlled to open, and the orifice solenoid valve is controlled to close after the electronic expansion valve is opened to a target opening.

[0061] In this regard, since there is a large amount of gaseous refrigerant in the fin heat exchanger when the machine is turned on, the impact at this time will also cause the valve body to vibrate. However, opening the bypass solenoid valve 6 flow path at this time will have no throttling effect, and there will be no pressure difference between high and low pressures, which will easily cause the compressor to idle after it is turned on. Therefore, when the machine is turned on, the orifice solenoid valve 7 is first opened. After the initial compressor operation time t3 (t3 is usually the initial operation time setting value for protecting the compressor, during which the compressor maintains minimum load and does not move), the main solenoid valve 8 is opened, and the electronic expansion valve 4 is opened to 50% opening. Then the orifice solenoid valve 7 is closed, and the electronic expansion valve 4 and the compressor are controlled normally.

[0062] The present application is explained below in conjunction with the specific implementation of the embodiment of the present application. The specific implementation provides a self-correction control method for an electronic expansion valve. Figure 1 , the method in this specific embodiment, such as Figure 3 Shown, including:

[0063] Step 301: During normal operation of the unit, it is detected that the electronic expansion valve is opened greater than or equal to 3 times or the valve opening is greater than or equal to 5% within time t1;

[0064] In this regard, the detection time t1 is usually set at 1~2 minutes. If the time is too short, the valve body adjustment cycle cannot keep up, and if it is too long, it is impossible to clearly distinguish whether the abnormality is caused by system operation or by the valve body.

[0065] Step 302: Determine the low pressure rise ratio ΔP L Is it less than or equal to m%?

[0066] In this regard, △P L is the change ratio of low pressure during time t1. The low pressure detection position is the compressor suction port. Assuming that the initial low pressure is P 始 After t1 time, the low pressure is P 终 , △P L =(P 终 -P 始 ) / P 始 , m% is the set value, usually set to 1%~2%.

[0067] Step 303: within time t1, determine whether the fan frequency increase rate is greater than or equal to Δf or the water temperature decrease rate is greater than or equal to ΔT;

[0068] In this regard, the fan frequency increase will cause the high pressure to decrease and the low pressure to decrease synchronously, offsetting the effect of the valve body opening on the low pressure. Also assuming that the initial fan frequency f 始 , after time t1, the fan frequency f 终 , frequency rise rate = (f 始 -f 终 ) / t1; Similarly, the water temperature drop will also cause the low pressure to drop, offsetting the effect of the valve opening on the low pressure. The water temperature drop rate = (f 始 -f 终 Therefore, if the fan frequency increase rate ≥ Δf or the water temperature decrease rate ≥ ΔT, it is considered to be the influence of the fan or water temperature, and no correction adjustment is required.

[0069] Step 304: determining that the actual valve opening is no longer in line with the target and requires correction and adjustment;

[0070] In step 305, the orifice solenoid valve 7 is first opened, and then the pressure P1 after the electronic expansion valve 4 is compared with the pressure P2 after the throttling orifice 5. When P1>P2, the electronic expansion valve 4 is adjusted to be closed, and when P1<P2, the electronic expansion valve 4 is adjusted to be opened. When P1=P2, the valve remains stationary. After the orifice solenoid valve 7 is opened, the absolute value of P1-P2 is synchronously calculated. When the absolute value is ≤X, the valve adjustment is stopped. It is considered that the actual valve opening at this time is 50%, and the target instruction and the displayed opening at this time are both corrected to 50%.

[0071] Step 306 , control the valve body from 0 to 50% again, detect the pressure P1 after the electronic expansion valve 4 and the pressure P2 after the throttle orifice 5 , and calculate the absolute value of P1-P2;

[0072] Step 307: Compare P1 and P2 and count n times to see if the absolute value of P1-P2 is less than or equal to Ps; if yes, proceed to step 308; if not, proceed to step 309;

[0073] Step 308: Reset is successful, the electronic expansion valve 4 is raised to 100% opening, and the orifice plate solenoid valve 7 is closed;

[0074] Step 309: When n is greater than or equal to 4, the unit synchronous feedback fails.

[0075] When comparing P1 and P2, the number of times is recorded each time the comparison is made. When the number of times recorded is n≥4, it indicates that the valve body is stuck in a fixed position and cannot be corrected or repaired. At this time, the valve body will no longer be opened or closed. The main solenoid valve 8 will be opened to maintain the current state. The whole machine will keep running and a fault alarm will be fed back synchronously: the expansion valve body is abnormal.

[0076] Corresponding to the above Figure 2 , the embodiment of the present application also provides a correction device for an electronic expansion valve, such as Figure 4 As shown, the device includes:

[0077] a first processing module 402 configured to, during operation of the air-cooled chiller, upon detecting an abnormality in an electronic expansion valve in the air-cooled chiller, open an orifice plate solenoid valve in the air-cooled chiller, and obtain a first pressure at an outlet of the electronic expansion valve and a second pressure at an outlet of a throttling orifice plate in the air-cooled chiller, wherein the electronic expansion valve and the throttling orifice plate are connected in parallel in the air-cooled chiller;

[0078] The second processing module 404 is configured to control the opening of the electronic expansion valve so that a first absolute value of the first pressure and the second pressure is less than a first preset threshold, and to display a target opening that matches the target instruction, wherein the target opening is the opening required for the electronic expansion valve to make the absolute value of the first pressure and the second pressure less than the first preset threshold;

[0079] The third processing module 406 is used to obtain the second absolute value of the first pressure and the second pressure when controlling the opening of the electronic expansion valve from zero to the target opening again, and determine whether the electronic expansion valve is calibrated successfully based on the comparison result of the second absolute value and the second preset threshold.

[0080] Through the device of the embodiment of the present application, when an abnormality of the electronic expansion valve is detected, the opening of the electronic expansion valve is adjusted so that the absolute value of the first pressure at the outlet of the electronic expansion valve and the second pressure at the outlet of the throttling orifice plate in the air-cooled chiller is less than a first preset threshold value. At this time, the opening of the electronic expansion valve can be considered to be the target opening. The target opening is known, so the currently displayed opening can also be set to the target opening. Then the opening of the electronic expansion valve is controlled from zero to the target opening again, and then the second absolute value of the first pressure and the second pressure is obtained again. If the second absolute value is less than the second preset threshold value, it indicates that the correction is successful. Otherwise, multiple corrections are required or it is determined that the electronic expansion valve is faulty. It can be seen that in the embodiment of the present application, after an abnormality occurs in the electronic expansion valve, it can be corrected by itself. After the correction is successful, the actual opening of the valve body can be guaranteed to be consistent with the target opening, thereby ensuring the stable operation of the entire system.

[0081] In an optional implementation manner of the embodiment of the present application, the second processing module in the embodiment of the present application may further include: a first processing unit, used to close the electronic expansion valve so that the first absolute value is less than the first preset threshold when the first pressure is greater than the second pressure and the first absolute value is greater than the first preset threshold; a second processing unit, used to open the electronic expansion valve so that the first absolute value is less than the first preset threshold when the first pressure is less than the second pressure and the first absolute value is greater than the first preset threshold; a third processing unit, used to maintain the opening of the electronic expansion valve unchanged when the first pressure is equal to the second pressure.

[0082] In an optional implementation manner of the embodiment of the present application, the third processing module in the embodiment of the present application may further include: a fourth processing unit, used to determine that the electronic expansion valve correction is successful when the second absolute value is less than or equal to the second preset threshold; a fifth processing unit, used to determine that the electronic expansion valve correction has failed this time when the second absolute value is greater than the second preset threshold, and to calibrate the electronic expansion valve again.

[0083] In an optional implementation manner of the embodiment of the present application, the device in the embodiment of the present application further includes: a fourth processing module, which is used to determine that the electronic expansion valve is abnormal when the number of times the electronic expansion valve is calibrated again exceeds a preset number.

[0084] In an optional implementation manner of an embodiment of the present application, the first processing module in the embodiment of the present application includes: a sixth processing unit, used to detect the low-pressure change ratio of the compressor suction port in the air-cooled chiller within the first preset time period; a seventh processing unit, used to detect whether the fan frequency increase rate within the first preset time period is greater than or equal to the fourth preset threshold or whether the water temperature drop rate is greater than or equal to the fifth preset threshold when the low-pressure change ratio is less than the third preset threshold; an eighth processing unit, used to determine that the electronic expansion valve is normal when the fan frequency increase rate within the first preset time period is greater than or equal to the fourth preset threshold or the water temperature drop rate is greater than or equal to the fifth preset threshold; a ninth processing unit, used to determine that the electronic expansion valve is abnormal when the fan frequency increase rate within the first preset time period is less than the fourth preset threshold and the water temperature drop rate is less than the fifth preset threshold.

[0085] In an optional implementation manner of the embodiment of the present application, the device in the embodiment of the present application also includes: a fifth processing module, which is used to control the opening of the bypass solenoid valve in the air-cooled chiller after receiving a shutdown command; a sixth processing module, which is used to close the electronic expansion valve after detecting that the high pressure at the exhaust port of the compressor and the low pressure at the intake port in the air-cooled chiller are balanced, and then close the bypass solenoid valve after the electronic expansion valve is closed.

[0086] In an optional implementation manner of the embodiment of the present application, the device in the embodiment of the present application also includes: a seventh processing module, used to control the orifice solenoid valve in the air-cooled chiller to open after receiving the power-on command; an eighth processing module, used to control the main solenoid valve in the air-cooled chiller to open after the compressor runs for a second preset time, and control the orifice solenoid valve to close after opening the electronic expansion valve to the target opening.

[0087] like Figure 5 As shown, the embodiment of the present application provides an air-cooled chiller, including a processor 511, a communication interface 512, a memory 513 and a communication bus 514, wherein the processor 511, the communication interface 512, and the memory 513 communicate with each other through the communication bus 514.

[0088] Memory 513, for storing computer programs;

[0089] In one embodiment of the present application, the processor 511 is used to execute the program stored in the memory 513 to implement the control method of the electronic expansion valve provided by any of the aforementioned method embodiments, and its role is similar and will not be repeated here.

[0090] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the electronic expansion valve control method provided in any of the aforementioned method embodiments are implemented.

[0091] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0092] Through the description of the above embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a general hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the relevant technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0093] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0094] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for calibrating an electronic expansion valve, characterized in that: include: During the operation of the air-cooled chiller, when an abnormality of an electronic expansion valve in the air-cooled chiller is detected, the orifice plate solenoid valve in the air-cooled chiller is opened, and a first pressure at an outlet of the electronic expansion valve and a second pressure at an outlet of a throttling orifice plate in the air-cooled chiller are obtained, wherein the electronic expansion valve and the throttling orifice plate are connected in parallel in the air-cooled chiller, the orifice plate solenoid valve and the throttling orifice plate are arranged on the same branch line, and the orifice plate solenoid valve is upstream of the throttling orifice plate on the branch line; controlling the opening of the electronic expansion valve so that a first absolute value of the first pressure and the second pressure is less than a first preset threshold, and displaying a target opening that matches the target instruction, wherein the target opening is the opening required for the electronic expansion valve to make the absolute value of the first pressure and the second pressure less than the first preset threshold; When controlling the opening of the electronic expansion valve from zero to the target opening again, obtaining second absolute values ​​of the first pressure and the second pressure, and determining whether the electronic expansion valve is successfully calibrated based on a comparison result of the second absolute value and a second preset threshold.

2. The method according to claim 1, characterized in that Controlling the opening of the electronic expansion valve so that a first absolute value of the first pressure and the second pressure is less than a first preset threshold includes: When the first pressure is greater than the second pressure and the first absolute value is greater than the first preset threshold, closing the electronic expansion valve so that the first absolute value is less than the first preset threshold; When the first pressure is lower than the second pressure and the first absolute value is higher than the first preset threshold, the electronic expansion valve is opened wider so that the first absolute value is lower than the first preset threshold; When the first pressure is equal to the second pressure, the opening of the electronic expansion valve is maintained unchanged.

3. The method according to claim 1, characterized in that Determining whether the electronic expansion valve is successfully calibrated according to a comparison result between the second absolute value and a second preset threshold value includes: When the second absolute value is less than or equal to the second preset threshold, determining that the electronic expansion valve calibration is successful; When the second absolute value is greater than the second preset threshold, it is determined that the current calibration of the electronic expansion valve has failed, and the electronic expansion valve is calibrated again.

4. The method according to claim 3, characterized in that The method further comprises: When the number of times the electronic expansion valve is recalibrated exceeds a preset number, it is determined that the electronic expansion valve is abnormal.

5. The method according to claim 1, wherein Detecting whether the electronic expansion valve in the air-cooled chiller is abnormal includes: detecting a low pressure change ratio at an air intake port of a compressor in the air-cooled chiller within a first preset time period; When the low pressure change ratio is less than the third preset threshold, detecting whether the fan frequency increase rate within the first preset time period is greater than or equal to the fourth preset threshold or whether the water temperature drop rate is greater than or equal to the fifth preset threshold; If the fan frequency increase rate is greater than or equal to the fourth preset threshold or the water temperature drop rate is greater than or equal to the fifth preset threshold within the first preset time period, determining that the electronic expansion valve is normal; When the fan frequency increase rate is less than the fourth preset threshold and the water temperature drop rate is less than the fifth preset threshold within the first preset time period, it is determined that the electronic expansion valve is abnormal.

6. The method according to claim 1, characterized in that After the electronic expansion valve is calibrated successfully, the method further includes: After receiving the shutdown command, controlling the bypass solenoid valve in the air-cooled chiller to open, wherein the bypass solenoid valve is arranged on a branch in parallel with the electronic expansion valve; After detecting that the high pressure at the exhaust port of the compressor and the low pressure at the intake port of the air-cooled chiller are balanced, the electronic expansion valve is closed and the bypass solenoid valve is closed after the electronic expansion valve is closed.

7. The method according to claim 6, characterized in that After the air-cooled chiller is shut down, the method further includes: After receiving the power-on command, the orifice plate solenoid valve of the air-cooled chiller is controlled to open; After the compressor runs for a second preset time, the main solenoid valve in the air-cooled chiller is controlled to open, and after the electronic expansion valve is opened to a target opening, the orifice solenoid valve is controlled to close, wherein the main solenoid valve and the electronic expansion valve are arranged on the same main line, and the main solenoid valve is upstream of the electronic expansion valve on the main line.

8. A calibration device for an electronic expansion valve, characterized in that: include: a first processing module, configured to, during operation of an air-cooled chiller, open an orifice plate solenoid valve in the air-cooled chiller and obtain a first pressure at an outlet of the electronic expansion valve and a second pressure at an outlet of a throttling orifice plate in the air-cooled chiller when an abnormality of the electronic expansion valve in the air-cooled chiller is detected, wherein the electronic expansion valve and the throttling orifice plate are connected in parallel in the air-cooled chiller, the orifice plate solenoid valve and the throttling orifice plate are arranged on the same branch line and the orifice plate solenoid valve is upstream of the throttling orifice plate on the branch line; a second processing module, configured to control the opening of the electronic expansion valve so that a first absolute value of the first pressure and the second pressure is less than a first preset threshold, and display a target opening that matches the target instruction, wherein the target opening is the opening required for the electronic expansion valve to make the absolute value of the first pressure and the second pressure less than the first preset threshold; a third processing module, configured to obtain second absolute values ​​of the first pressure and the second pressure when controlling the opening of the electronic expansion valve from zero to the target opening again, and determine whether the electronic expansion valve is successfully calibrated based on a comparison result of the second absolute value and a second preset threshold.

9. An air-cooled chiller, characterized in that: include: at least one communication interface; at least one bus connected to the at least one communication interface; at least one processor coupled to the at least one bus; At least one memory connected to the at least one bus, wherein the processor is configured to execute the electronic expansion valve calibration method according to any one of claims 1 to 7.

10. A computer storage medium, characterized in that Computer-executable instructions are stored, and the computer-executable instructions are used to execute the calibration method of the electronic expansion valve according to any one of claims 1 to 7.

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