Stall diagnosis method based on automatic calibration of stall current

Abstract

The application relates to a kind of automatic calibration based on stall current stall diagnosis method, comprising the following steps: step 1, to stall current automatic calibration;Step 2, according to stall current stall judgment;According to the stall current stall judgment step includes: according to the current speed of motor by stall diagnosis current lookup table obtains the current stall diagnosis current threshold, according to the current speed of motor by stall diagnosis filter time lookup table obtains the current stall diagnosis filter threshold;When the actual current of motor is greater than stall diagnosis current threshold, current abnormal diagnosis timing is increased, otherwise current abnormal diagnosis timing is reduced;When current abnormal diagnosis timing is greater than stall diagnosis filter threshold, stall flag is set to true;When current abnormal diagnosis timing is equal to 0, stall flag is set to false.The beneficial effects of the application: realize the automatic calibration of stall current threshold, filter the condition of exceeding the set threshold in time domain at the same time, reduce the risk of misdiagnosis.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of based on stall current automatic calibration stall diagnosis method. BACKGROUND

[0002] In three-phase fan cooling system, fan is usually installed in the place of ventilation, and the side of fan blade is installed radiator, and the other side is in open state for keeping ventilation. When working, foreign matter can enter the open side of fan, causing fan blade to stall and unable to start. If fan cannot identify stall state after stall, it can continue to run under large load and low speed, causing motor to heat and even cause fire.

[0003] In the electronic control unit of the known three-phase fan system, stall is judged by detecting whether bus current exceeds the set current threshold. When bus current fluctuates, it is easy to cause misdiagnosis. SUMMARY

[0004] The present application aims to provide a kind of based on stall current automatic calibration stall diagnosis method to solve the problems raised in the background.

[0005] To achieve the above object, the present application provides the following technical solutions:

[0006] A kind of based on stall current automatic calibration stall diagnosis method, comprising the following steps:

[0007] Step 1, automatic calibration of stall current;

[0008] Step 2, stall is judged according to stall current;

[0009] Wherein, the step of automatic calibration of stall current includes:

[0010] Step 1.1, set the desired speed of motor to motor desired speed minimum value, and set stall current automatic calibration completion flag to false;

[0011] Step 1.2, detect the actual speed of motor, when the actual speed of motor and the desired speed of motor error is within the allowable error value range of the actual speed of motor, execute step 1.3, otherwise repeat step 1.2;

[0012] Step 1.3, record the maximum value, minimum value and average value of the current of motor, repeat step 1.3, record the time of step 1.3 execution, when the time of step 1.3 execution exceeds the set detection time, execute step 1.4, wherein the result of using the average value of the current of motor multiplied by stall diagnosis current threshold coefficient is used as stall diagnosis current threshold;

[0013] Step 1.4, comparing the current of the motor with the average value of the current of the motor recorded in step 1.3, recording the time when the current of the motor is greater than the average value of the current of the motor recorded in step 1.3; recording the time when step 1.4 is executed, and executing step 1.5 when the time when step 1.4 is executed exceeds the set detection time, wherein the result of using the time when the current of the motor is greater than the average value of the current of the motor recorded in step 1.3 divided by the total time of step 1.4, multiplied by the stall diagnosis filtering time coefficient, is used as the stall diagnosis filtering time;

[0014] Step 1.5, recording the expected speed of the motor and the stall diagnosis current threshold into the stall diagnosis current lookup table; recording the expected speed of the motor and the stall diagnosis filtering time into the stall diagnosis filtering time lookup table;

[0015] Step 1.6, if the expected speed of the motor is greater than or equal to the maximum value of the expected speed of the motor, setting the stall current automatic calibration completion flag to true, setting the expected speed of the motor to 0, and ending the stall current automatic calibration function; if the expected speed of the motor is less than the maximum value of the expected speed of the motor, increasing the expected speed of the motor by the expected speed step value of the motor and repeating steps 1.2 to 1.6;

[0016] The step of judging the stall according to the stall current comprises:

[0017] The current stall diagnosis current threshold is obtained from the stall diagnosis current lookup table according to the current speed of the motor, and the current stall diagnosis filtering threshold is obtained from the stall diagnosis filtering time lookup table according to the current speed of the motor; the current abnormal diagnosis time is increased when the actual current of the motor is greater than the stall diagnosis current threshold, and the current abnormal diagnosis time is decreased otherwise; the stall flag is set to true when the current abnormal diagnosis time is greater than the stall diagnosis filtering threshold; and the stall flag is set to false when the current abnormal diagnosis time is equal to 0.

[0018] As a further scheme of the application, the motor is a three-phase motor.

[0019] As a further scheme of the application, the motor is a fan.

[0020] As a further scheme of the application, the detected current of the motor is the bus current of the motor.

[0021] Compared with the prior art, the application has the beneficial effect of realizing automatic calibration of the stall current threshold, and reducing the risk of misdiagnosis by time domain filtering of conditions exceeding the set threshold.

[0022] Other features and advantages of the application will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a flow chart of automatic stalling current calibration of a stalling diagnosis method based on automatic stalling current calibration. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0025] As shown in Figure 1 , a stalling diagnosis method based on automatic stalling current calibration in an embodiment of the present application comprises the following steps:

[0026] Step 1, automatic calibration of stalling current;

[0027] Step 2, stalling judgment according to stalling current.

[0028] As a specific embodiment, the input of the stalling current calibration function is a stalling current calibration enable flag, a current of the motor, an actual speed of the motor, an actual speed error value of the motor, a minimum value of the expected speed of the motor, a maximum value of the expected speed of the motor, a step value of the expected speed of the motor, a motor current detection time, a stalling diagnosis current threshold coefficient, and a stalling diagnosis filter time coefficient.

[0029] The output of the stalling current calibration function is a stalling current automatic calibration completion flag, an expected speed of the motor, a stalling diagnosis current threshold, and a stalling diagnosis filter time.

[0030] When the stalling current calibration enable flag is false, the stalling current calibration is not performed. When the stalling current calibration enable flag is true, the stalling current automatic calibration is performed.

[0031] Specifically, the step of automatic calibration of stalling current comprises:

[0032] Step 1.1, setting the expected speed of the motor to the minimum value of the expected speed of the motor and setting the stalling current automatic calibration completion flag to false;

[0033] Step 1.2, detecting the actual speed of the motor, and when the error between the actual speed of the motor and the expected speed of the motor is within the allowed error value of the actual speed of the motor, executing step 1.3, otherwise repeating step 1.2;

[0034] Step 1.3, record the maximum value, the minimum value, the average value of the current of the motor, repeat step 1.3, record the time when step 1.3 is executed, when the time when step 1.3 is executed exceeds the set detection time, execute step 1.4, wherein the result of the average value of the current of the motor multiplied by the locked-rotor diagnostic current threshold coefficient is used as the locked-rotor diagnostic current threshold;

[0035] Step 1.4, compare the current of the motor with the average value of the current of the motor recorded in step 1.3, record the time when the current of the motor is greater than the average value of the current of the motor recorded in step 1.3; record the time when step 1.4 is executed, when the time when step 1.4 is executed exceeds the set detection time, execute step 1.5, wherein the result of the time when the current of the motor is greater than the average value of the current of the motor recorded in step 1.3 divided by the total time of step 1.4, multiplied by the locked-rotor diagnostic filter time coefficient, is used as the locked-rotor diagnostic filter time;

[0036] Step 1.5, record the expected speed of the motor and the locked-rotor diagnostic current threshold into the locked-rotor diagnostic current lookup table; record the expected speed of the motor and the locked-rotor diagnostic filter time into the locked-rotor diagnostic filter time lookup table;

[0037] Step 1.6, if the expected speed of the motor is greater than or equal to the maximum value of the expected speed of the motor, set the locked-rotor current automatic calibration completion flag to true, set the expected speed of the motor to 0, and end the locked-rotor current automatic calibration function; if the expected speed of the motor is less than the maximum value of the expected speed of the motor, increase the expected speed of the motor by the expected speed of the motor step value, and repeat steps 1.2 to 1.6.

[0038] Specifically, the step of judging the locked-rotor according to the locked-rotor current comprises:

[0039] According to the current speed of the motor, the current locked-rotor diagnostic current threshold is obtained through the locked-rotor diagnostic current lookup table, and the current locked-rotor diagnostic filter threshold is obtained through the locked-rotor diagnostic filter time lookup table according to the current speed of the motor; when the actual current of the motor is greater than the locked-rotor diagnostic current threshold, the current abnormality diagnosis time is increased, otherwise the current abnormality diagnosis time is decreased; when the current abnormality diagnosis time is greater than the locked-rotor diagnostic filter threshold, the locked-rotor flag is set to true; when the current abnormality diagnosis time is equal to 0, the locked-rotor flag is set to false.

[0040] As a specific embodiment, the motor is a three-phase motor. Specifically, the motor is a fan. The detected current of the motor is the bus current of the motor. As an optional embodiment, the motor is not limited to a three-phase motor or a fan.

[0041] It will be obvious to a person skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims should be considered as limiting the scope of the claims to the identity of the reference signs therein.

[0042] Furthermore, it should be understood that although the description is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A stall rotor diagnostic method based on automatic stall rotor current calibration, characterized in that, Includes the following steps: Step 1: Automatically calibrate the stall current; Step 2: Determine if the rotor is locked based on the locked rotor current; The steps for automatic calibration of the locked-rotor current include: Step 1.1: Set the desired motor speed to the minimum desired motor speed, and set the stall current automatic calibration completion flag to false; Step 1.2: Detect the actual speed of the motor. If the error between the actual speed of the motor and the expected speed of the motor is within the allowable error value of the actual speed of the motor, proceed to step 1.3; otherwise, repeat step 1.

2. Step 1.3: Record the maximum, minimum, and average values ​​of the motor current. Repeat step 1.3 and record the execution time of step 1.

3. When the execution time of step 1.3 exceeds the set detection time, execute step 1.

4. The average value of the motor current multiplied by the stall current diagnostic threshold coefficient is used as the stall current diagnostic threshold. Step 1.4: Compare the motor current with the average value of the motor current recorded in Step 1.3, and record the time during which the motor current is greater than the average value of the motor current recorded in Step 1.3; record the execution time of Step 1.

4. When the execution time of Step 1.4 exceeds the set detection time, execute Step 1.

5. The stall diagnosis filtering time is obtained by dividing the time during which the motor current is greater than the average value of the motor current recorded in Step 1.3 by the total time of Step 1.4, and then multiplying the result by the stall diagnosis filtering time coefficient. Step 1.5: Record the desired speed of the motor and the stall current threshold in the stall current lookup table; record the desired speed of the motor and the stall filtering time in the stall filtering time lookup table; Step 1.6: If the desired speed of the motor is greater than or equal to the maximum desired speed of the motor, then set the automatic stall current calibration completion flag to true, set the desired speed of the motor to 0, and end the automatic stall current calibration function; if the desired speed of the motor is less than the maximum desired speed of the motor, then increase the desired speed of the motor by the desired speed step value and repeat steps 1.2 to 1.

6. The steps for determining the stall condition based on the stall current include: The current stall current threshold is obtained from the stall current lookup table based on the current speed of the motor, and the current stall filter threshold is obtained from the stall filter lookup table based on the current speed of the motor. When the actual current of the motor is greater than the stall current threshold, the current anomaly diagnosis timer is increased; otherwise, the current anomaly diagnosis timer is decreased. When the current anomaly diagnosis timer is greater than the stall filter threshold, the stall flag is set to true; when the current anomaly diagnosis timer is equal to 0, the stall flag is set to false.

2. The stall rotor diagnosis method based on automatic stall rotor current calibration according to claim 1, characterized in that, The motor is a three-phase motor.

3. The stall diagnosis method based on automatic stall current calibration according to claim 2, characterized in that, The motor is a fan.

4. The stall rotor diagnosis method based on automatic stall rotor current calibration according to claim 1, characterized in that, The current detected in the motor is the bus current of the motor.

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