CN112787567B

CN112787567B - Control method and system

Info

Publication number: CN112787567B
Application number: CN201911086196.XA
Authority: CN
Inventors: 不公告发明人
Original assignee: Hangzhou Sanhua Research Institute Co Ltd
Current assignee: Hangzhou Sanhua Research Institute Co Ltd
Priority date: 2019-11-08
Filing date: 2019-11-08
Publication date: 2023-01-06
Anticipated expiration: 2039-11-08
Also published as: CN112787567A

Abstract

The invention discloses a control method, which is used for controlling a motor, wherein a control device stores or presets a normal threshold value and a locked-rotor threshold value which correspond to the motor, the normal threshold value is greater than the locked-rotor threshold value, when the motor runs, the back electromotive force or the related quantity of the motor is obtained, and the average value Bm of the back electromotive force or the related quantity of the back electromotive force of the motor is obtained; the obtained back electromotive force or the average value Bm of the related quantity of the back electromotive force of the motor is compared with the normal threshold and the locked rotor threshold, so that the working state that the motor runs normally or is possibly locked rotor is obtained, and the judgment is relatively reliable through the setting of the two thresholds.

Description

Control method and system

Technical Field

The invention relates to the field of electric control, in particular to a control method and a control system.

Background

When the motor runs normally in the running process, the current of a motor coil can change according to a normal rule; another situation is that the motor may occasionally cause a locked-rotor condition, i.e. a condition in which the motor rotates at 0 and still outputs torque, referred to herein as a locked-rotor condition, in which the current of the motor coil may exceed the rated current of the motor. The motor and even the system can be influenced to a certain extent, so that the effective running state of the motor is judged, and the subsequent problems caused by the locked rotor of the motor can be effectively reduced by correspondingly controlling the motor, thereby achieving the purpose of more effective running of the motor and the whole system.

Disclosure of Invention

The application provides a control method and a control system, which enable the system to operate more effectively.

The system can be used for a system with a motor, and further comprises a control device, wherein the control device stores or presets a normal threshold value and a locked-rotor threshold value corresponding to the motor, and the normal threshold value is greater than the locked-rotor threshold value;

the control method comprises the following steps of a, b and c, wherein at least one of the steps is as follows:

a, when the motor runs, obtaining the counter electromotive force or the related quantity of the counter electromotive force of the motor; processing the data of the counter electromotive force or the related quantity of the counter electromotive force of the motor to obtain an average value Bm of the counter electromotive force or the related quantity of the counter electromotive force of the motor;

comparing the obtained average value Bm of the back electromotive force or the related quantity of the back electromotive force of the motor with the normal threshold value, and judging whether the average value Bm of the back electromotive force or the related quantity of the back electromotive force of the motor is larger than the normal threshold value or whether the normal threshold value is smaller than the average value Bm of the back electromotive force or the related quantity of the back electromotive force of the motor;

and c, comparing the obtained back electromotive force or the average value Bm of the related quantity of the back electromotive force of the motor with the locked rotor threshold value, and judging whether the average value Bm of the related quantity of the back electromotive force or the back electromotive force of the motor is smaller than the locked rotor threshold value or whether the locked rotor threshold value is larger than the average value Bm of the related quantity of the back electromotive force or the back electromotive force of the motor.

The order of the steps b and c is not limited, and the two steps can be adjusted back and forth. The order of the other steps in this document is not intended to be limiting unless explicitly stated.

Meanwhile, a system is also provided, which comprises a control device and a motor, wherein the control device comprises a memory, a temporary memory or a random memory, and the memory stores an initial value of the normal threshold, an initial value of a locked rotor threshold, an initial value of the motor counter electromotive force or the average value of the related quantities thereof in a normal running state, and an initial value of the motor counter electromotive force or the average value of the related quantities thereof in a locked rotor state; the temporary memory or the random access memory is used for storing data of a normal threshold value, a locked rotor threshold value, and the back electromotive force or the related quantity of the back electromotive force of the motor; the system operates as described above in the control method.

The technical scheme, the control method and the control system can be used for self-adaptive detection and control of the motor or used as auxiliary control of the motor, and the system can be controlled more reliably by setting a normal threshold and a locked rotor threshold and enabling the normal threshold to be larger than the locked rotor threshold in a method relative to a single threshold.

Drawings

FIG. 1 is a schematic diagram of the local logic of a control method of an embodiment;

FIG. 2 is a schematic logic diagram of a portion of a control method according to another embodiment;

FIG. 3 is a schematic view of a portion of the logic of a control method according to yet another embodiment;

FIG. 4 is a flow diagram illustrating one manner of obtaining dynamic normal and locked rotor thresholds;

FIG. 5 is a schematic illustration of one result of dynamic verification using the present control method;

FIG. 6 is a schematic diagram of a partial logic of a control method according to another embodiment;

FIG. 7 is a schematic flow chart of obtaining dynamic normal and locked-rotor thresholds;

FIG. 8 is a schematic flow chart of the motor state determination;

FIG. 9 is a partial flow diagram of motor control after obtaining motor status;

FIG. 10 is a partial flow diagram of a motor jump determination;

FIG. 11 is another partial flow diagram of motor jump determination;

FIG. 12 is a schematic view of another partial flow chart of the motor jump determination;

FIG. 13 is a partial flow diagram of a threshold update.

Detailed Description

In order to make those skilled in the art better understand the technical solutions of the present invention, the technical solutions will be described below with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments, not all embodiments, of the technical solutions of the present invention. Modifications, combinations, and substitutions may be made by those skilled in the art based on these embodiments, and all other embodiments obtained by those skilled in the art without making any inventive changes should be within the scope of the present invention.

When the motor runs, the counter electromotive force can be changed according to the specific running condition of the used system, for example, different loads, such as different motor rotating speeds, the counter electromotive force can be differentiated, and the motor can occasionally have a locked-rotor condition due to various reasons and special conditions. The back electromotive force of the motor in normal operation and locked rotor is different.

The running working conditions of the motors are different, when different loads run at different speeds, the back electromotive force of the motors can be changed during normal running, and the back electromotive force of the motors during locked rotor can be distinguished; the back electromotive force of the same load motor under the two working conditions of normal operation and locked rotor is different. Therefore, when different loads operate, the threshold value for judging the operation state of the motor is preferably changed according to the operation condition; the threshold for distinguishing normal operation and locked rotor of the motor is preferably adjusted correspondingly when the motor is under different loads and at different speeds, and is referred to as the normal threshold and the locked rotor threshold, so that whether the motor is in normal operation or locked rotor is dynamically judged, and adaptive dynamic control is performed, so that accurate judgment can be performed more accurately according to the counter electromotive force of the motor or the related quantity of the counter electromotive force.

The correlation amount of the back electromotive force may be a positive correlation or a negative correlation, and the positive correlation is specifically described as an example below.

Referring to fig. 1, the local logic of one of the control methods may be combined with fig. 7, and the method includes the following steps:

and S11, when the motor runs, acquiring the back electromotive force of the motor or the related quantity Bemf of the back electromotive force at regular intervals. The related quantity of the back electromotive force means that the corresponding back electromotive force can be obtained according to the related quantity, such as a digital quantity or other electric signals related to the back electromotive force obtained by a sampling circuit, so that the back electromotive force can be obtained. The acquired interval time can be specifically set and adjusted, such as 10ms or 5ms or even 2ms interval time and the like; and storing the collected or obtained back electromotive force of the motor or the related quantity Bemf thereof into a temporary memory or a random access memory, wherein the memory can store corresponding data, such as 6 groups or 10 groups or 20 groups, and the like, and the newly obtained back electromotive force or the related quantity of data can replace the originally stored group of data.

The number of sets of data stored may be determined, resulting in a new set of data replacing the relatively oldest set of data in the set of data.

Step S12, removing the maximum value and the minimum value of the collected back electromotive force or the related quantity Bemf thereof, and averaging the rest groups of data to obtain the average value of the back electromotive force or the average value Bm of the related quantity of the back electromotive force;

step S13, comparing the obtained back electromotive force or the average value Bm of the related quantity Bemf with a stored normal threshold Br or an initial value of the normal threshold Br; if Bm > Br, go to step S15, if Bm is not greater than Br, go to step S14.Bm > Br shows that the motor is in a normal operation state.

When the operation is started, if the temporary memory or the random access memory does not have the normal threshold Br, the initial value of the normal threshold stored in the memory can be adopted; such as reading the initial value of the normal threshold of the memory as the normal threshold.

Step S14, comparing the obtained back electromotive force or the average value Bm of the related quantity Bemf with a locked rotor threshold value Bs or an initial value thereof; if Bm < Bs, go to step S16, if Bm is not less than Bs, go to step S11; bm < Bs indicates that the motor may be in a locked-rotor state.

When the operation is started, if the temporary memory or the random access memory has no locked-rotor threshold Bs, the initial value of the locked-rotor threshold stored in the memory can be adopted; for example, an initial value of the locked-rotor threshold of the memory is read as the locked-rotor threshold.

Step S15, updating the normal threshold Br: according to the original normal threshold Br and the average value Bm, the normal threshold Br is given again through operation, namely, the normal threshold Br is properly adjusted according to the running back electromotive force or the average value Bm of the relevant quantity Bemf, so that the normal threshold Br is more reliable; the specific examples include: br + Bm (1-A) C2, and a new normal threshold Br is given after operation; wherein a is an adjustment coefficient, which may specifically be as follows: 0.7, 0.8, 0.9, etc., A is greater than or equal to 0.7; c2 is a normal threshold coefficient, and 0.5 is constructed with C2 less than or equal to 0.9.

In addition, the calculation may also be performed based on the original normal threshold Br, the obtained average Bm and the stored average at the time of the original locked-rotor, that is, the new Br is related to the original normal threshold Br, the average of the back electromotive force of the current normal operation, and the average of the back electromotive force of the original locked-rotor.

Step S16, judging whether the motor is in an initialization stage, and if so, turning to step S17; if not, go to step S18;

s17, completing motor initialization, and turning to S11;

and step S18, judging that the motor is possibly in a locked-rotor state. The motor locked-rotor signal can be sent out for alarming; or the motor is debugged in a locked-rotor manner, if the motor rotates forwards and backwards to improve locked-rotor, the judgment is carried out again; or the motor is judged to be possibly in a locked-rotor state, and a signal is sent out to further combine other signals for judgment and the like. The locked-rotor threshold Bs can be updated at the same time: according to the original locked-rotor threshold value Bs and the current average value Bm, operation is carried out to endow the locked-rotor threshold value Bs again, namely, according to the running back electromotive force or the average value Bm of the related quantity Bemf, the locked-rotor threshold value Bs is properly adjusted, and the locked-rotor threshold value Bs is more reliable; the specific examples include: bs + Bm (1-B) C1; wherein B is an adjustment coefficient, which may specifically be: 0.7, 0.8, 0.9, etc., B is greater than or equal to 0.7; c1 is a locked-rotor threshold coefficient, and 2 is formed by the yarns C1. In addition, the stalling threshold Bs may also be updated after a certain number of times, such as 2 times, 3 times, or 5 times.

Or the calculation can be performed according to the original stalling threshold Bs, the obtained average value Bm of the current back electromotive force or the related quantity and the original normal running back electromotive force or the related quantity average value, that is, the new stalling threshold Bs is related to the original normal running back electromotive force average value, the current running back electromotive force average value and the original stalling threshold; the new normal threshold Br is associated with the average value of back emf for normal operation and the average value of back emf for the original stall and the original normal threshold.

Obtaining the possible locked rotor of the motor through the counter electromotive force, and judging that the motor is initialized in an initialization stage; if the motor stalling strategy is executed in the non-initialization stage, for example, the current command is executed or the motor is directly stopped after stalling occurs, and the command of an upper computer is waited for initialization or automatic initialization or further judgment and the like; or locked-rotor debugging can be performed first.

Therefore, when a system motor operates, the system detection and judgment can be more reliable through the setting of the normal threshold and the locked-rotor threshold, and the normal threshold or the locked-rotor threshold is dynamically updated as necessary, so that the normal threshold or the locked-rotor threshold is more suitable for the actual system operation condition, can be used for self-adaptive detection and control or used as auxiliary control of the motor, can adapt to the control requirement of the change of the specific operation condition, can effectively avoid the subsequent problems caused by the locked-rotor fault of the motor, and correspondingly improves the judgment accuracy, thereby achieving the purpose of protecting the motor and the whole system.

An additional embodiment is described below with reference to fig. 2 in conjunction with fig. 7. The control method comprises the following steps:

and S21, when the motor runs, acquiring the back electromotive force of the motor or the related quantity Bemf of the back electromotive force at regular intervals. The quantity or parameter of the back electromotive force can be obtained by the related quantity of the back electromotive force such as a digital quantity or other electric signals obtained by a sampling circuit. The acquired interval time can be specifically set and adjusted, such as 10ms or 5ms or even 2ms interval time and the like; the collected back electromotive force of the motor or the related quantity Bemf thereof is stored in a temporary memory (random access memory), the memory can store corresponding data, such as 6 groups, 10 groups, 20 groups and the like, and the collected data can replace the originally stored group of data.

The number of sets of data stored may be determined, resulting in new data replacing the relatively oldest set of data in the set of data.

Step S22, removing the maximum value and the minimum value or removing abnormal values such as abnormally large or abnormally small values from the collected back electromotive force or the related quantity Bemf thereof, and averaging the rest of groups of data to obtain an average value Bm of the back electromotive force or the related quantity Bemf thereof;

step S23, comparing the obtained back electromotive force or the average value Bm of the correlation Bemf with a stored normal threshold Br; if Bm > Br, go to step S25, if Bm is not greater than Br, go to step S24.Bm > Br shows that the motor is in a normal operation state.

Step S24, comparing the obtained back electromotive force or the average value Bm of the related quantity Bemf with the stored locked rotor threshold value Bs; if Bm < Bs, go to step S26, if Bm is not less than Bs, go to step S21; bm < Bs indicates that the motor may be in a locked-rotor state.

Step S25, updating the normal threshold Br: calculating according to the original normal threshold Br and the average value Bm, and endowing the normal threshold Br again, namely properly adjusting the normal threshold Br according to the running back electromotive force or the average value Bm of the relevant quantity Bemf thereof, so that the normal threshold Br is more reliable; the specific examples include: br + Bm (1-A) C2, and a new normal threshold Br is given after the operation; wherein a is an adjustment coefficient, which may specifically be: 0.7, 0.8, 0.9, etc., A is greater than or equal to 0.7; c2 is a normal threshold coefficient, and the 0.5-woven fabric C2 is less than or equal to 0.9.

In addition, the calculation can also be performed according to the original normal threshold Br, the obtained average value Bm and the average value stored in the original locked-rotor state, that is, the new Br is related to the original normal threshold Br, the average value of the back electromotive force of the current normal operation and the average value of the back electromotive force of the original locked-rotor state.

Or judging whether the back electromotive force of the motor or the average value Bm of the related quantity of the back electromotive force is greater than a normal threshold value for n times continuously, and if not, continuing to detect and judge; if so, updating the normal threshold Br;

and S26, judging that the motor is possibly in a locked-rotor state, sending a motor locked-rotor signal for alarming, or carrying out locked-rotor debugging processing on the motor, if the motor rotates forwards and backwards to improve locked-rotor, then judging again, or sending a signal to enable the system to further combine with other systems for judging, and the like. The locked rotor threshold Bs can be updated at the same time: calculating according to the original locked rotor threshold value Bs and the average value Bm, and endowing the locked rotor threshold value Bs again, namely, properly adjusting the locked rotor threshold value Bs according to the running back electromotive force or the average value Bm of the relevant quantity Bemf thereof, so that the locked rotor threshold value Bs is more reliable; the operation formula may specifically be as follows: bs + Bm (1-B) C1; wherein B is an adjustment coefficient, which may specifically be: 0.7, 0.8, 0.9, etc., B is greater than or equal to 0.7; c1 is a locked-rotor threshold coefficient, and 2 are constructed into C1.

The updating of the threshold value can also be carried out according to whether the counter electromotive force of the motor or the average value Bm of the related quantity of the counter electromotive force is continuously smaller than the locked rotor threshold value for n1 times, so as to update the locked rotor threshold value Bs, and if not, the detection and the judgment are continuously carried out; if yes, updating the locked rotor threshold Bs.

Or the new locked rotor threshold Bs is related to the original normal running back electromotive force or the related quantity average value, the current running back electromotive force or the related quantity average value and the original locked rotor threshold value; the new normal threshold Br is associated with the average of the back emf or related quantities for normal operation and the average of the back emf or related quantities for the original stall and the original normal threshold.

This embodiment may be applied to the control of the normal operation process, i.e. the way the further control is initiated. In addition, the above embodiment may be changed, for example, it may be determined whether the value is smaller than the locked-rotor threshold, and then determined whether the value is larger than the normal threshold.

In addition, the depolarization value can also be in another mode, such as removing some obviously abnormal data and the like. Referring to fig. 3, the control method includes the following steps:

and S31, when the motor runs, acquiring the back electromotive force of the motor or the related quantity Bemf of the back electromotive force at regular intervals. The relative amount of the back electromotive force, such as a digital quantity or other electric signals obtained by a sampling circuit, can be used for obtaining the quantity or parameters of the back electromotive force. The acquired interval time can be specifically set and adjusted, such as 10ms or 5ms or even 2ms interval time and the like; the collected back electromotive force of the motor or the related quantity Bemf thereof is stored in a temporary memory (random access memory), the memory can store corresponding data, such as 5 groups, 6 groups, 10 groups or 20 groups, and the collected data can replace the originally stored group of data.

The number of sets of data stored may be determined, resulting in a new set of data that may replace the relatively oldest set of data in the set of data.

Step S32, removing abnormal high or low values from the acquired data to calculate the average value, and calculating the average value of the acquired data if no abnormal value exists; or removing the maximum value and the minimum value, and averaging the rest groups of data; obtaining the average value of the back electromotive force or the average value Bm of the related quantity thereof;

step S33, comparing the obtained average value of the back electromotive force or the average value Bm of the related quantity thereof with the stored locked rotor threshold value Bs; if Bm < Bs, go to step S34, and if Bm is not less than Bs, go to step S36.Bm < Bs indicates that the motor may be in a locked-rotor state.

Step S34, according to the obtained average value of the back electromotive force or the average value Bm of the related quantity thereof and the original locked rotor threshold value Bs, operation is carried out to endow the locked rotor threshold value Bs again, namely, according to the running average value of the back electromotive force or the average value Bm of the related quantity thereof, the locked rotor threshold value Bs is properly adjusted, so that the locked rotor threshold value Bs is more reliable; the specific new stalling threshold Bs may be as follows: bs B + Bm (1-B) C1. In addition, whether or not to update the stalling threshold Bs may be determined based on whether or not the counter electromotive force of the motor or the average value Bm of the counter electromotive force correlation amount is smaller than the stalling threshold n1 times in succession.

And S35, judging whether the motor is possibly in a locked-rotor state, sending a motor locked-rotor signal for alarming, or performing anti-locked-rotor treatment on the motor, if the motor rotates in forward and reverse directions to improve locked-rotor, judging again or judging whether the motor is possibly in the locked-rotor state, sending a signal to enable the system to further combine other judgment, and the like. Further, the lock-up threshold Bs may be updated from step S33 directly to step S35.

Step S36, comparing the obtained average value of the back electromotive force or the average value Bm of the related quantity thereof with a normal threshold Br; if Bm is greater than Br, updating the normal threshold Br, and turning to the step S31; if Bm is not greater than Br, go to step S31.Bm > Br shows that the motor is in a normal operation state.

Updating a normal threshold Br: calculating according to the original normal threshold Br and the average value, and endowing the normal threshold Br again, namely properly adjusting the normal threshold Br according to the average value of the running back electromotive force or the average value Bm of the related quantity thereof, so that the normal threshold Br is more reliable; specifically, the method can comprise the following steps: br + Bm (1-A) C2, and a new normal threshold Br is given after operation;

wherein a is an adjustment coefficient, which may specifically be: 0.7, 0.8, 0.9, etc., A is greater than or equal to 0.7; c2 is a normal threshold coefficient, and the 0.5-woven fabric C2 is less than or equal to 0.9.B is an adjustment coefficient, which may specifically be as follows: 0.7, 0.8, 0.9, etc., B is greater than or equal to 0.7; c1 is a locked-rotor threshold coefficient, and 2 are constructed into C1.

Or according to the original lock-rotor threshold Bs, the obtained average value Bm and the stored average value in the original normal operation, that is, the new lock-rotor threshold Bs is related to the original normal operation back electromotive force average value, the current operation back electromotive force average value and the original lock-rotor threshold; the new normal threshold Br is associated with the average of the back emf for normal operation and the average of the back emf for the original stall and the original normal threshold.

Referring now to fig. 4, in another embodiment, the control method includes the steps of:

step S41, when the motor runs, acquiring a normal threshold Br and a locked rotor threshold Bs, or acquiring initial values of the normal threshold Br and the locked rotor threshold Bs as the normal threshold Br and the locked rotor threshold Bs;

in step S42, an average value of the back electromotive forces of the motor operation or an average value Bm of the correlation thereof is acquired. Specifically, the back electromotive force of the motor or the related quantity Bemf thereof may be collected at regular intervals. The relative amount of back emf is, for example, a digital quantity or other electrical signal obtained by a sampling circuit. The time interval of the acquisition can be set and adjusted, such as the time interval of 10ms or 5ms or even 2ms and the like; the obtained back electromotive force or the related quantity Bemf thereof can be stored in a temporary memory or a random access memory, the memory can store corresponding data, such as 6 groups or 10 groups or 20 groups, and the like, the collected data of the back electromotive force can replace the originally stored group of data, and then the data are processed to obtain an average value. The number of sets of data stored may be determined, resulting in new data, which may replace the relatively oldest set of data with new data.

Step S43, judging whether the motor is locked, if so, turning to step S44, and if not, turning to step S45, according to the obtained initial values of the normal threshold Br and the locked-rotor threshold Bs or the initial values of the normal threshold Br and the locked-rotor threshold Bs, and the average value of the back electromotive force or the related quantity Bemf thereof;

in step S44, the stalling threshold Bs is updated. According to the obtained average value of the back electromotive force or the average value Bm of the related quantity thereof and the initial value of the original locked rotor threshold value Bs, the original locked rotor threshold value Bs is calculated and updated by the obtained locked rotor threshold value Bs, namely, the locked rotor threshold value Bs is properly adjusted according to the running average value of the back electromotive force or the average value Bm of the related quantity thereof, so that the locked rotor threshold value Bs can be dynamically updated, and the control is more reliable; specifically, the following operations can be performed: bs + A + Bm (1-A) C1 to obtain a new locked rotor threshold value Bs; in addition, counting can also be carried out, the locked rotor threshold Bs is updated after n1 times of continuous counting is reached, n1 is an integer, for example, the value ranges from 2 to 5, if a non-locked rotor state occurs in the middle, n1 is reset, and counting is restarted;

and step S45, judging whether the motor is in a normal running state, and if so, updating the normal threshold Br. Specifically, the obtained average value of the back electromotive force or the average value Bm of the related quantity thereof is compared with a stored normal threshold, if the motor is judged to be in a normal running state, the original normal threshold Br is updated by calculating the obtained normal threshold Br after operation, that is, the normal threshold Br is appropriately adjusted according to the average value of the running back electromotive force or the average value Bm of the related quantity thereof, and the normal threshold Br is dynamically adjusted by combining the current running working condition of the motor, which specifically includes the following operations: br a + Bm (1-a) C2, resulting in a new normal threshold Br. In addition, counting can also be carried out, the normal threshold Br is updated after n times of continuous reaching, n is an integer, for example, between 2 and 5, if an abnormal state occurs in the middle, n is reset, and counting is restarted.

Wherein a is an adjustment coefficient, which may specifically be: 0.7, 0.8, 0.85, 0.9, etc., A is greater than or equal to 0.7; c2 is a normal threshold coefficient, and the 0.5-woven fabric C2 is less than or equal to 0.9. C1 is a locked-rotor threshold coefficient, and 2 is formed by the yarns C1.

Or the new lock-rotor threshold Bs is related to the original normal running back electromotive force or the related quantity average value, the current running back electromotive force or the related quantity average value and the original lock-rotor threshold value; the new normal threshold value Br is related to the normal running counter electromotive force average value, the original locked-rotor counter electromotive force average value and the original normal threshold value; the initial value can be used as a reference initially, and the dynamic normal threshold or locked rotor threshold is used as a reference after operation.

By using the control method, the threshold value is correspondingly adjusted along with the running working condition of the motor, and the probability of misjudgment caused by the mode of setting the fixed threshold value is reduced aiming at the counter electromotive force fluctuation caused by the change of the working condition. The use of two thresholds makes the determination relatively more reliable. Fig. 5 is a schematic diagram of one result of dynamic threshold verification using the present control method. The normal threshold Br and the locked rotor threshold Bs can be properly changed along with the change of the back electromotive force related quantity Bm, so that the control is more stable and reliable, and the possibility of misjudgment is reduced. Bemf is the actual acquisition result, which is the AD sampling result, and is positively correlated with the back electromotive force. In addition, the actual voltage value can be used, step is position operation feedback of a product, for example, the actual mechanical stroke of the product for the motor is 3093 half steps, and in order to acquire locked-rotor BEMF data, the software stroke of the product is set to 4000 half steps, so that in the process of product operation, after the stroke exceeds 3093 half steps, the locked-rotor condition occurs. From the Bemf acquisition results, it can be seen that in the locked rotor state, the Bemf value is relatively smaller than the result of normal operation. Br is a normal threshold value, namely the BEMF exceeding the threshold value is judged to be normal; and Bs is a locked rotor threshold value, namely the BEMF is smaller than the threshold value to judge that the locked rotor is possible. The normal threshold Br is larger than the locked rotor threshold Bs, the locked rotor threshold Bs is larger than most of back electromotive force when the motor is locked, and the normal threshold Br is smaller than most of back electromotive force when the motor normally runs; the normal threshold Br is larger than the average value of the counter electromotive force when the motor is locked and the counter electromotive force when the motor normally runs, and the locked-rotor threshold Bs is smaller than the average value of the counter electromotive force when the motor normally runs and the counter electromotive force when the motor is locked; or the normal threshold Br is larger than the average value of the back electromotive force when the motor is locked and the average value of the back electromotive force during normal operation, and the locked threshold Bs is smaller than the average value of the back electromotive force when the motor is normally operated and the average value of the back electromotive force during locked operation.

In addition, the control method may further include the embodiment shown in fig. 6, and the control method includes the steps of:

and S61, when the motor runs, acquiring the back electromotive force of the motor or the related quantity Bemf of the back electromotive force at certain time intervals.

The relative amount of back emf is, for example, a digital quantity or other electrical signal obtained by a sampling circuit. The acquired interval time can be specifically set and adjusted, such as 10ms or 5ms or even 2ms interval time and the like; the collected back electromotive force of the motor or the related quantity Bemf thereof is stored in a temporary memory, i.e. a random access memory, the memory can store corresponding data, such as 6 groups or 10 groups or 20 groups, and the like, and the collected back electromotive force or the related quantity Bemf thereof can replace the originally stored group of data. The number of sets of data stored may be determined, resulting in a new set of data that may replace the relatively oldest set of data in the set of data.

Step S62, removing abnormal values, such as a particularly high value or a particularly low value, of the collected back electromotive force or the related quantity Bemf thereof, and averaging the rest of the groups of data; if no abnormal value exists, averaging the obtained data; obtaining the average value of the back electromotive force or the average value Bm of the related quantity thereof;

step S63, comparing the obtained average value of the back electromotive force or the average value Bm of the related quantity thereof with a stored normal threshold Br, starting to have no normal threshold, and comparing the normal threshold with an initial value of the normal threshold; if Bm is greater than Br, updating the normal threshold Br or counting, and updating the normal threshold Br after the counting reaches n times; and returns to step S61; if Bm is not greater than Br, go to step S64; bm > Br shows that the motor is in a normal running state;

step S64, comparing the obtained average value of the back electromotive force or the average value Bm of the related quantity thereof with the original locked rotor threshold value Bs, and if no locked rotor threshold value exists, comparing the obtained average value with an initial locked rotor threshold value; if Bm < Bs, go to step S65, if Bm is not less than Bs, go to step S61.Bm < Bs indicates that the motor can be in a locked-rotor state;

and step S65, judging that the motor is possibly in a locked-rotor state, sending a motor locked-rotor signal alarm or a signal to a control device or an upper computer, or carrying out locked-rotor debugging on the motor, such as locked-rotor processing program, for example, carrying out forward and reverse rotation to improve locked-rotor, and then carrying out judgment again, and the like. In addition, the stalling threshold Bs may be updated simultaneously, or counted, the stalling threshold Bs may be updated after the count reaches n times, n1 is an integer, such as between 2-5 or 3-8, and if a non-stalling state occurs in the middle, n1 is reset, and the counting is restarted.

Referring to fig. 7, the control method includes the following steps:

step S71, when the motor runs, acquiring initial values of the normal threshold Br and the locked rotor threshold Bs or both, and acquiring an average value of the back electromotive force of the running motor or an average value Bm of the related quantity thereof. Specifically, the back electromotive force of the motor or the related quantity Bemf thereof may be collected at regular intervals. The relative amount of back emf is, for example, a digital quantity or other electrical signal obtained by a sampling circuit. The time interval of the acquisition can be specifically adjusted, such as 10ms or 5ms or even 2ms time interval and the like; the collected back electromotive force of the motor or the related quantity Bemf thereof is stored in a temporary memory, i.e., a random access memory, the random access memory can store corresponding data, such as 6 groups, 10 groups, 20 groups and the like, the collected data can replace the originally stored group of data, and then the data is used for obtaining an average value. The number of sets of data stored may be determined, resulting in new data, and the relatively oldest set of data may be replaced with the new data.

Step S72, judging whether the motor is locked according to the obtained normal threshold Br, the locked-rotor threshold Bs or the initial value and the average value of the back electromotive force or the related quantity Bemf thereof, if so, turning to step S73, and if not, turning to step S74; the initial values of the normal threshold value Br and the locked rotor threshold value Bs can be original values stored in a memory, or the normal threshold value Br and the locked rotor threshold value Bs stored in a temporary memory in the last operation;

in step S73, the lock-up threshold Bs is updated. Calculating and updating the original locked rotor threshold value Bs by the obtained locked rotor threshold value Bs according to the obtained average value of the back electromotive force or the average value Bm of the related quantity of the back electromotive force and the original locked rotor threshold value Bs, namely properly adjusting the locked rotor threshold value Bs according to the average value of the running back electromotive force or the average value Bm of the related quantity of the running back electromotive force to enable the locked rotor threshold value Bs to be more suitable for the requirements of actual running working conditions; specifically, the following operations can be performed: bs + Bm (1-B) C1 to obtain a new locked rotor threshold value Bs; alternatively, counting may be performed, wherein the stall threshold Bs is updated after n1 consecutive times, n1 being an integer, such as between 2-5 or 3-8, and if a non-stall condition occurs in the middle, n1 is reset and counting is resumed.

Wherein B is an adjustment coefficient, which may specifically be: 0.7, 0.8, 0.9, 0.85, etc., B is greater than or equal to 0.7; c1 is a locked-rotor threshold coefficient, and 2 is formed by the yarns C1.

And step S74, judging whether the motor is in a normal running state, and if so, updating the normal threshold Br. Specifically, the obtained average value of the back electromotive force or the average value Bm of the related quantity thereof is compared with the stored normal threshold Br or the initial value thereof, if the motor is judged to be in the normal running state, the normal threshold Br is updated by the calculated normal threshold Br after the operation, that is, the normal threshold Br is properly adjusted according to the average value Bm of the running back electromotive force or the average value of the related quantity thereof, and the normal threshold Br is more reliable by combining the current running working condition of the motor, and specifically, the operation can be as follows: br a + Bm (1-a) C2, resulting in a new normal threshold Br.

Wherein a is an adjustment coefficient, which may specifically be: 0.7, 0.8, 0.9, 0.85, etc., A is greater than or equal to 0.7; c2 is a normal threshold coefficient, and the 0.5-woven fabric C2 is less than or equal to 0.9.

In addition, the calculation can also be performed according to the original stalling threshold Bs, the obtained average Bm and the stored back electromotive force or the average value of the related quantity during the original normal operation, that is, the new stalling threshold Bs is related to the back electromotive force or the average value of the related quantity during the original normal operation, the back electromotive force or the average value of the related quantity during the current operation and the original stalling threshold; the new normal threshold value Br is related to the back electromotive force or the average value of the related quantity of the normal operation, the original blocked back electromotive force or the average value of the related quantity and the original normal threshold value;

according to the embodiment, the initial values of the reasonable normal threshold and the locked rotor threshold are set and stored in the system or the control product according to the characteristics of the control product used by the motor. And simultaneously, the counter electromotive force or related data in the normal operation state and the counter electromotive force or related data in the locked rotor state can be stored. And during actual operation, dynamically updating the back electromotive force data in the normal operation state according to the obtained back electromotive force related data in the normal operation state, and dynamically updating the related data in the locked rotor state according to the obtained back electromotive force or related quantity data in the locked rotor state. When the operation is started, the normal threshold value can be dynamically updated by the initial value of the normal threshold value and the BEMF data in the normal operation state, and the locked-rotor threshold value can be dynamically updated by the initial value of the locked-rotor threshold value and the BEMF data in the locked-rotor state; or the normal threshold value can be dynamically updated according to the initial value of the normal threshold value, the back electromotive force related data in the normal running state and the back electromotive force related data in the locked rotor state, and the locked rotor threshold value can be dynamically updated according to the initial value of the locked rotor threshold value, the back electromotive force related data in the locked rotor state and the back electromotive force related data in the normal running state; and then, the updated normal threshold and locked rotor threshold are used for carrying out self-adaptive dynamic control, so that even if the system applied by the motor is changed greatly, the dynamic control can be adapted and carried out. Specifically, the original data is replaced by the obtained new threshold, that is, the finally obtained normal threshold and the locked rotor threshold are stored in the temporary memory after each operation and are used for the next operation; or, the original stored initial values of the normal threshold and the locked-rotor threshold are called each time the operation is started, the stored initial values of the normal threshold and the locked-rotor threshold can be stored in the memory, the original initial values are called each time the operation is started, the updated threshold is only used for the operation, the updated data are stored in the random access memory, and the initial values are kept in the memory unchanged. The control method can generate a threshold value for dynamic judgment according to the actual running condition, and the dynamic judgment threshold value is used as a judgment basis for judging the motor locked rotor or normal running; and judging the filtered back electromotive force according to the dynamically judged threshold value, outputting a state result for an upper-layer control strategy to apply, and taking the state result as a main or auxiliary basis for judging locked rotor.

The control method can also refer to fig. 8, and the subroutine is mainly used for obtaining the motor state, updating the motor state and performing corresponding control, and the method comprises the following steps:

and S81, acquiring the back electromotive force of the motor or the related quantity Bemf of the back electromotive force at regular intervals when the motor runs. The related quantity of the back electromotive force is a quantity or parameter of the back electromotive force which can be obtained through digital quantity or other electric signals obtained by a sampling circuit. The time interval of the acquisition can be specifically adjusted, such as 10ms or 5ms or even 2ms time interval and the like; the collected back electromotive force of the motor or the related quantity Bemf thereof is stored in a temporary memory (random access memory), the memory can store corresponding data, such as 5 groups, 6 groups, 10 groups or 20 groups, and the collected back electromotive force data can replace the originally stored group of data.

The number of data sets stored in the temporary memory may be determined, a new set of data may be obtained, and the relatively oldest set of data in the data sets may be replaced. Initially data can be read from the memory. The data stored in the memory may include an initial value of a normal threshold, an initial value of a locked rotor threshold, BEMF data for a locked rotor state, BEMF data for a normal operating state. These data can remain unchanged, thus requiring memory and temporary storage; in addition, updates may be made so that only one memory need be included.

Step S82, removing abnormal high or low values of the acquired data, and averaging the acquired data if no abnormal value exists; or removing the maximum value and the minimum value, and averaging the rest groups of data; obtaining the average value of the back electromotive force or the average value Bm of the related quantity thereof;

step S83, is the original motor status locked? If yes, go to S84, if no, go to S86;

step S84, comparing the obtained average value of the back electromotive force or the average value Bm of the related quantity thereof with the stored locked rotor threshold value Bs; if Bm < Bs, it is determined that the motor is in the locked state and step S85 is performed, and if Bm is not less than Bs, it is determined that the motor may not be in the locked state and step S85 is performed. Bm < Bs indicates that the motor may be in a locked-rotor state.

And step S85, obtaining the current motor state, namely the locked-rotor state, and switching to a corresponding motor drive control program, and meanwhile, updating the threshold value when the conditions are met.

Step S86, comparing the obtained average value of the back electromotive force or the average value Bm of the related quantity thereof with a stored normal threshold Br; if Bm is greater than Br, the motor belongs to the normal operation state and goes to step S85, and if Bm is not greater than Br, it is determined that the motor may not belong to the normal operation state and goes to step S85.

For specific motor control, as shown in fig. 9, this is a schematic diagram of a subroutine of motor control, and includes the following steps:

step S91, is the motor state normal running state (i.e., motor state R)? If yes, turning to S92 or normal operation, returning to obtain information again and judging, and if not, turning to S93;

step S92, the motor normally runs and returns;

in step S93, is the motor state locked (i.e., motor state S)? If yes, go to S95, if no, go to S94;

step S94, stopping the motor;

in step S95, is the motor initialized? If yes, go to S96, if no, go to S97;

step S96, the motor initialization is completed, and the motor is returned to a normal running state to control the running of the motor;

step S97, sending out an alarm signal: and (4) motor stalling or debugging and processing the motor stalling.

In addition, as shown in fig. 10, this is a schematic diagram of an embodiment of determining whether the motor jumps during a normal operation process, and may be specifically applied to a combination application when a suspected motor of the system is locked, or to a subroutine for a normal determination during a normal operation, and specifically includes the following steps:

step S101, in a normal running state (motor state R) of the motor, acquiring an average value of back electromotive force of the motor or an average value Bm of related quantity of the back electromotive force;

step S102, comparing the obtained average value Bm with the previous average value Bm0 of the back electromotive force or the BEMF of the related quantity, judging whether the current average value Bm is smaller than the previous average value Bm0, if so, turning to S103, and if not, returning to the previous-stage program or returning to S101; bm is not less than the last average value Bm0, which indicates that the point is not a trip point and can exclude the possibility of being the trip point;

step S103, an absolute value Δ Bm of a difference between the current average value Bm and the previous average value Bm0 of the back electromotive force or the correlation BEMF; or calculating the difference delta Bm between the average value Bm0 of the BEMF of the back electromotive force of the previous time and the average value of the current time;

step S104, whether the delta Bm is larger than or equal to a first set value V1 or whether the accumulation of the difference of the average values of more than two continuous times, such as three continuous times, is larger than or equal to a second set value V2 or not; if yes, judging that the counter electromotive force of the motor jumps downwards to a certain degree, namely possibly a jump point, turning to step S106, and if not, turning to step S105;

step S105, judging whether the current point is a trip point, returning to a previous-level program or resetting and returning to S101;

step S106, judging whether the current point is a trip point, and adding 1 to the count N; and S107;

step S107, whether the jumping point count N reaches N or not is judged to be jumping if the jumping point count N reaches N; if not, go to S101.n is an integer of 1 or more, and specifically may be 1, 2, 3, 5 or the like. If the sum of the differences Δ Bm of several times, such as two times and three times, is adopted as judged by S104, n may be 1; if step S104 determines whether the difference Δ Bm is equal to or greater than the first setting value V1, n may be 3, which is only an example. Because the back emf that appears at one time may be a disturbance caused by a system anomaly, while 2 or 3 consecutive times are generally less likely to disturb.

Some of the above steps may be replaced by some similar functions, or combined, for example, step S102 and step S103 may be combined, and step S106 and step S107 may be combined. If the back electromotive force or the related quantity Bemf of the motor changes to the opposite direction in the process, the occasional interference is possible, the jumping point can be basically eliminated, and the back electromotive force or the related quantity Bemf changes to the same direction for a certain amount for n times continuously, the motor jumps, and if the motor is in the original normal operation state, the motor is continuously reduced for 3 times, and the motor is possibly locked.

The counter electromotive force or the related quantity Bemf changes a certain quantity in the same direction continuously for n times, wherein n is larger than or equal to 2, the motor jumps, if in a locked-rotor state, a locked-rotor processing program is operated, the counter electromotive force or the related quantity Bemf continuously increases for n times, such as 3 times, the motor is possibly converted into a normal operation state and is not locked. Referring to fig. 11, a schematic diagram of a subroutine for determining whether the motor is in a normal operation state in a locked-rotor state includes the following steps:

step S111, in a motor locked-rotor state (motor state S), the system runs a locked-rotor debugging program to obtain the counter electromotive force of the motor or the average value Bm of the BEMF of the related quantity of the motor;

step S112, comparing the obtained average value Bm with the previous average value Bm0, judging whether the current average value Bm is more than or equal to the previous average value Bm0, if so, turning to S113, and if not, returning to the previous-stage program or returning to S111; bm is not larger than the last average value Bm0, which indicates that the point is not a trip point and can exclude the possibility of being the trip point;

step S113, obtaining a difference Δ Bm between the current average value Bm and the previous average value Bm0 of the BEMF of the back electromotive force;

step S114, whether Δ Bm is equal to or greater than the first set value V1 or whether the cumulative sum of differences of average values of consecutive times, such as two times, three times, four times, five times, is equal to or greater than the second set value V2; if yes, judging that the counter electromotive force of the motor jumps upwards to a certain degree, namely possibly a jump point, and turning to the step S116, otherwise, turning to the step S115;

step S115, judging whether the current point is a trip point, returning to the previous-level program or resetting and returning to the step S111;

step S116, judging whether the current point is a trip point, and adding 1 to the count N; and S117;

step S117, whether the jumping point count N reaches N or not is judged to be jumping if the jumping point count N reaches N, and the previous-stage program can be returned, and or corresponding information is fed back to the control device or the system at the same time; if not, go to S111.n is an integer of 1 or more, and specifically may be 1, or 2, or 3, or 5. The sum of the differences Δ Bm taken several times in succession, e.g. two or three or more times, as judged at S114, n may be 1; if step S114 determines whether the difference Δ Bm is greater than or equal to the first setting value V1, n may be 3, which is only an example. Because the back emf that appears at one time may be a disturbance caused by a system anomaly, while 2 or 3 consecutive times are generally less likely to disturb.

Some of the above steps may be replaced by some similar functions, or combined, for example, step S112 and step S113 may be combined, or step S111, step S112 and step S113 may be combined; step S116 and step S117 may be combined.

In addition, the jump judging procedure can also be changed, mainly by judging whether Bm changes and whether the direction of change is the same all the time, as shown in fig. 12, which is a schematic diagram of another subroutine for judging whether to block the rotation, and includes the following steps:

step S121, obtaining the back electromotive force of the motor or the average value Bm of the related quantity BEMF; comparing the obtained average value Bm with the previous average value Bm0, judging whether the current average value Bm is larger than the previous average value Bm0, if so, turning to S122, and if not, turning to S131;

step S122, obtaining the difference delta Bm between the average value Bm of the current time and the average value Bm0 of the previous back electromotive force or the related quantity BEMF;

step S123, whether the delta Bm is larger than or equal to a first set value V1 or whether the accumulation of the difference of the average values of three times of continuous times is larger than or equal to a second set value V2; if yes, judging that the counter electromotive force of the motor jumps upwards to a certain degree, namely possibly a jump point, turning to step S124, if not, judging that the counter electromotive force is not the jump point, counting, resetting and returning to the upper-level program;

step S124, judging whether the trip point is possible, and adding 1 to the count N; and S125;

step S125, whether the jumping point count N reaches N or not is judged, if yes, jumping is judged, the previous stage program can be returned, and or corresponding information is fed back to the control system at the same time; if not, go to S121;

step S131, obtaining the back electromotive force of the motor or the average value Bm of the related quantity BEMF or the average value of the related quantity thereof; comparing the obtained average value Bm with the previous average value Bm0, judging whether the current average value Bm is smaller than the previous average value Bm0, if so, turning to S132, and if not, returning to the previous-stage program;

step S132, obtaining the absolute value delta Bm of the difference between the average value Bm of the current time and the average value Bm0 of the previous back electromotive force or the related quantity BEMF;

step S133, whether the delta Bm is larger than or equal to a first set value V1 or whether the accumulation of the difference of the average values of the delta Bm for continuous times such as three times is larger than or equal to a second set value V2; if yes, judging that the counter electromotive force of the motor jumps downwards to a certain degree, namely possibly a jump point, turning to step S134, if not, judging that the counter electromotive force is not the jump point, counting, resetting and returning to the upper-level program;

step S134, judging whether the trip point is possible, and adding 1 to the count N; and S125;

step S135, whether the jumping point count N reaches N or not is judged to be jumping if the jumping point count N reaches N, and the previous-stage program can be returned, and or the corresponding information is fed back to the control system at the same time; if not, turning to S131, continuing to acquire Bm and judging.

n is an integer of 1 or more, specifically 1, or 2, or 3, or 5, and the like, and may be related to the sampling interval and the determination method. Judging as S114, using the sum of several consecutive times, such as three times of difference Δ Bm, n can be 1; if step S114 determines whether the difference Δ Bm is greater than the first set value V1, n may be 3, which is only an example. Because the back emf that appears at one time may be a disturbance caused by a system anomaly, while 2 or 3 consecutive times are generally less likely to disturb.

Some of the above steps may be replaced by some similar functions, or combined, for example, step S124 and step S125 may be combined, or step S122 and step S123 may be combined, or step S132 and step S133 may be combined, and step S134 and step S135 may be combined.

An operation flow of the normal threshold Br and the locked-rotor threshold Bs is described below, referring to fig. 13, which includes the following steps:

step S141, when the motor runs, acquiring the initial value of the normal threshold Br and the locked rotor threshold or the initial value of the normal threshold Br and the initial value of the locked rotor threshold Bs, and the average value of the back electromotive force or the average value Bm of the related quantity thereof;

step S142, determine whether the motor is locked? Or acquiring the running working state of whether the motor is locked; if the result is locked rotor, go to step S143, if not, go to step S144;

step S143, updating the stalling threshold Bs: obtaining a new locked rotor threshold value Bs according to the locked rotor threshold value Bs, the average value Bms of the average value Bm of the counter electromotive force or the related quantity Bemf thereof during locked rotor and the average value Bmr of the average value Bm of the counter electromotive force or the related quantity Bemf thereof during normal operation of the motor, and updating the locked rotor threshold value; specifically, a new locked rotor threshold Bs is given: bs B1+ (Bmr + Bms) (1-B1) C3/2;

step S144, determine whether the motor is in a normal operation state? Or acquiring whether the motor normally runs; if yes, updating the normal threshold Br or turning to the step S145;

a step S145; updating a normal threshold Br: obtaining a new normal threshold Br according to the original normal threshold Br, the average value Bms of the counter electromotive force or the average value Bm of the related quantity Bemf during the locked rotor and the average value Bmr of the counter electromotive force or the average value Bm of the related quantity Bemf during the normal running of the motor, and updating the normal threshold; the normal threshold value Br is closer to the actual running state, so that the control is more reliable; specifically, the following operations can be performed: br A1+ (Bmr + Bms) (1-A1) × C4/2, resulting in a new normal threshold Br;

wherein, A1 and B1 are adjustment coefficients, which may specifically be as follows: 0.7, 0.85, 0.9, etc., A1 is greater than 0.7, B1 is greater than 0.7; c4 is a normal threshold coefficient, 1-woven fabric C4 is less than or equal to 1.3, C3 is a locked-rotor threshold coefficient, and 0.5-woven fabric C3 is less than or equal to 0.9.

Specifically, according to the obtained average value Bm of the back electromotive force or the related quantity thereof and the current working running state, if the current working running state is locked rotor, the data of the average value Bm of the back electromotive force or the related quantity thereof at the time of locked rotor is updated, and if the current working running state is the normal running state, the data of the average value Bm of the back electromotive force or the related quantity thereof at the normal running state is updated, such as updating a group of data thereof; then obtaining the average value Bms of the new locked-rotor back electromotive force or the average value Bm of the related quantity Bemf thereof or the average value Bmr of the normal running back electromotive force or the average value Bm of the related quantity Bemf thereof of the motor according to the updated data; and then obtaining a threshold value needing to be updated in the current working state according to the original normal threshold value and the locked rotor threshold value Bs or the initial value of the normal threshold value Br and the initial value of the locked rotor threshold value Bs, if the current locked rotor is locked, updating the locked rotor threshold value Bs, and if the current locked rotor is in normal operation, updating the normal threshold value Br. And the system performs control and judgment according to the updated threshold value. For example, the memory may store the initial value of the most original normal threshold Br, the initial value of the most original locked-rotor threshold Bs, and the data of the locked-rotor back electromotive force or its related quantity Bemf or the data of the average Bm, the data of the motor normal operation back electromotive force or its related quantity Bemf or the data of the average Bm; when the system starts to run, the data can be read and stored in the random access memory, and subsequent updating and operation are carried out through the data of the random access memory, such as calculation, updating and the like. Alternatively, the data retained last time at each run time may be used as the basic data, and these may be selected.

Bemf, in addition to being the back emf, may also be an electrical quantity or a digital signal related to the back emf, such as an AD sampling result related to the back emf, or may also be an actual voltage value.

The initial value of the normal threshold Br and the initial value of the locked rotor threshold Bs can be obtained by the following method: the motor is enabled to normally operate, a certain amount of motor back electromotive force or related quantity Bemf thereof is obtained when the motor operates under various working conditions, after data processing or pole removing is carried out, the average value is calculated, and the obtained average value is discounted to obtain an initial value of a normal threshold Br; initial value of locked-rotor threshold Bs: the method comprises the steps that a motor runs under a locked-rotor condition, a certain number of motor back electromotive forces or related quantities Bemf of the motor back electromotive forces are obtained, after data processing or a depolarization value is carried out, an average value is obtained, and the obtained average value is multiplied by a coefficient larger than 1 to obtain an initial value of a locked-rotor threshold value Bs; or, letting the motor normally operate, operate under various working conditions, obtain data of back electromotive force or its related quantity Bemf of a certain number of motors in normal operation, after data processing or a depolarization value, calculate an average value, obtain an average value Bmr of the back electromotive force or its related quantity Bemf average value Bm in normal operation of the motor, let the motor operate under a locked-rotor condition, obtain data of the back electromotive force or its related quantity Bemf of a certain number of motors in locked-rotor condition, obtain an average value Bms of the back electromotive force or its related quantity Bemf average value Bm in locked-rotor condition of the motor, obtain a normal threshold Br and a locked-rotor threshold Bs according to the average value Bmr of the back electromotive force or its related quantity Bemf average value Bm in normal operation of the motor, and the average value Bms of the back electromotive force or its related quantity Bemf average value Bm in locked-rotor condition of the motor, such as:

Br＝x1*Bmr+y1*Bms；

Bs＝x2*Bmr+y2*Bms；

x1 and y1 are normal threshold coefficients, x2 and y2 are locked-rotor threshold coefficients, wherein x1 is more than or equal to 0.5 and less than 0.9, and x2 is less than 0.5.

In addition, the average value Bmr of the average value Bm of the counter electromotive force or the related quantity Bemf thereof when the motor normally operates and the average value Bms of the average value Bm of the counter electromotive force or the related quantity Bemf thereof when the motor is locked can be obtained by averaging the two, the normal threshold Br is obtained by multiplying the average value of the two by a coefficient larger than 1, and the locked rotor threshold Bs is obtained by discounting the average value of the two; if the normal threshold Br is X times, for example 1.2 times, the average of the average Bmr of the mean Bms of the back electromotive forces or the related quantities Bemf thereof during normal operation of the motor, the average Bmr of the mean Bms of the back electromotive forces or the related quantities Bemf thereof during the stalling of the motor, and the y times, for example 0.8 times, the average of the mean Bmr of the back electromotive forces or the related quantities Bemf thereof during normal operation of the motor, the average Bms of the mean Bms of the back electromotive forces or the related quantities Bemf thereof during the stalling of the motor: br = x (Bmr + Bms)/2, bs = y (Bmr + Bms)/2, x is more than or equal to 1.15, y is less than or equal to 0.85.

In summary, the control method provided by the application is more reliable in control by setting the normal threshold Br or the stalling threshold Bs in a manner of being relative to a single threshold, and further, when the motor runs, the normal threshold Br or the stalling threshold Bs is dynamically updated according to the actual running state by using the actual counter electromotive force of the motor or the data of the relevant quantity Bemf of the counter electromotive force, and the control is performed according to the updated threshold, so that the control is closer to the actual running needs. The control device can be arranged independently, such as being matched with the motor or being arranged together with the motor; in addition, the system used by the motor can also be provided with a corresponding control module, for example, the motor is applied to an automobile air conditioning system, the control device can be a module of the automobile air conditioning system, or the control device of the automobile air conditioning system controls the motor by applying the control method.

The above description is only an example of the technical solution of the present invention, and is not intended to limit the present invention in any way. Those skilled in the art can make many possible variations and modifications to the disclosed solution, or to modify equivalent embodiments, without departing from the scope of the solution, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are within the scope of the technical solution of the present invention, unless the technical essence of the present invention is not departed from the content of the technical solution of the present invention.

Claims

1. A control method can be used for a system with a motor, and the system also comprises a control device, wherein the control device stores or presets a normal threshold and a locked rotor threshold corresponding to the motor, and the normal threshold is greater than the locked rotor threshold;

the control method comprises a step a and at least one of the steps b and c:

a, obtaining the counter electromotive force or the related quantity of the counter electromotive force of the motor when the motor runs; processing the data of the back electromotive force or the related quantity of the back electromotive force of the motor to obtain an average value Bm of the back electromotive force or the related quantity of the back electromotive force of the motor;

b, comparing the obtained average value Bm of the back electromotive force or the related quantity of the back electromotive force of the motor with the normal threshold, judging whether the average value Bm of the back electromotive force or the related quantity of the back electromotive force of the motor is larger than the normal threshold or whether the normal threshold is smaller than the average value Bm of the back electromotive force or the related quantity of the back electromotive force of the motor, updating the normal threshold if the average value Bm of the back electromotive force or the related quantity of the back electromotive force of the motor is larger than the normal threshold, and turning to the step c if the average value Bm of the back electromotive force or the related quantity of the back electromotive force of the motor is not larger than the normal threshold;

c, comparing the obtained back electromotive force or the average value Bm of the related quantity of the back electromotive force of the motor with the locked rotor threshold value, judging whether the motor is in an initialization stage or executing a locked rotor strategy if the average value Bm of the related quantity of the back electromotive force or the back electromotive force of the motor is smaller than the locked rotor threshold value or not or the locked rotor threshold value is larger than the average value Bm of the related quantity of the back electromotive force or the back electromotive force of the motor, and returning to the step a or returning to the previous-stage program if the average value Bm of the related quantity of the back electromotive force or the back electromotive force of the motor is not smaller than the locked rotor threshold value.

2. The control method according to claim 1, characterized in that the control method further comprises at least one of steps d and e:

d, updating the normal threshold value; the normal threshold value is related to the original normal threshold value, the motor back electromotive force in the normal running state or the average value of the related quantity of the motor back electromotive force;

e, updating the locked rotor threshold value; the locked rotor threshold value is related to the original locked rotor threshold value, the motor back electromotive force in the locked rotor state or the average value of the related quantity of the motor back electromotive force;

and the control device replaces the original normal threshold value with the updated normal threshold value to carry out dynamic control, or the control device replaces the original locked-rotor threshold value with the updated locked-rotor threshold value to carry out dynamic control.

3. The control method according to claim 1, further comprising at least one of steps d and e:

d, updating the normal threshold value; the normal threshold value is related to the original normal threshold value, the average value of the motor back electromotive force or the related quantity thereof in the normal running state and the average value of the motor back electromotive force or the related quantity thereof in the locked-rotor state;

e, updating the locked rotor threshold value; the locked rotor threshold value is related to the original locked rotor threshold value, the average value of the motor back electromotive force or the related quantity thereof in the locked rotor state, and the average value of the motor back electromotive force or the related quantity thereof in the normal running state;

4. The control method according to claim 1, characterized in that:

the step b further comprises the following steps: if the back electromotive force of the motor or the average value Bm of the related quantity of the back electromotive force is larger than a normal threshold value, turning to the step f;

if the back electromotive force of the motor or the average value Bm of the related quantity of the back electromotive force is smaller than the locked rotor threshold value, turning to a step g;

in addition, the method also comprises the following steps:

step f: whether the back electromotive force of the motor or the average value Bm of the related quantity of the back electromotive force is continuously greater than the normal threshold value for n times or not, if not, returning to the step a; if yes, go to step d;

step g: whether the counter electromotive force of the motor or the average value Bm of the related quantity of the counter electromotive force is less than the locked rotor threshold value for n1 times continuously or not, if not, returning to the step a; if yes, turning to step e;

d, updating the normal threshold value;

and e, updating the locked rotor threshold value.

5. The control method according to claim 1, characterized in that:

before the step b, the step c also comprises a step e if the back electromotive force of the motor or the average value Bm of the related quantity of the back electromotive force is less than a locked rotor threshold value; if not, turning to the step b;

if the back electromotive force of the motor or the average value Bm of the related quantity of the back electromotive force is larger than a normal threshold, turning to the step d; if not, returning to the step a or returning to the upper-level program;

d, updating the normal threshold value;

and e, updating the locked rotor threshold value.

6. The control method according to any one of claims 2, 4, and 5, wherein the updating the normality threshold includes: and (3) performing the following operation on the original normal threshold Br and the counter electromotive force of the motor in normal operation or the average value Bm of the related quantity of the counter electromotive force: br + Bm (1-a) C2, assigning the obtained result to a new normal threshold Br;

wherein A is an adjustment coefficient, and A is greater than or equal to 0.7; c2 is a normal threshold coefficient, and the 0.5-woven fabric C2 is less than or equal to 0.9;

the updating the locked rotor threshold value comprises: and (3) performing the following operation on the original lock-rotor threshold Bs and the counter electromotive force or the average value Bm of the related quantity of the counter electromotive force when the motor is locked-rotor: bs + Bm (1-B) C1, and assigning the obtained result to a new stalling threshold Bs;

wherein B is an adjustment coefficient, and B is greater than or equal to 0.7; c1 is a locked-rotor threshold coefficient, and 2 is formed by the yarns C1.

7. The control method according to any one of claims 3, 4, and 5, wherein the updating the normal threshold value includes: and performing the following operations on the original normal threshold Br, the average value Bms of the average value Bm of the counter electromotive force or the related quantity Bemf when the motor is locked and the average value Bmr of the average value Bm of the counter electromotive force or the related quantity Bemf when the motor normally runs: br + A1+ (Bmr + Bms) (1-A1) × C4/2, obtaining a new normal threshold Br, and endowing the obtained result with the new normal threshold Br;

the updating the locked rotor threshold value comprises: according to the original locked rotor threshold Bs, the average value Bms of the average value Bm of the counter electromotive force or the related quantity Bemf thereof during locked rotor and the average value Bmr of the average value Bm of the counter electromotive force or the related quantity Bemf thereof during normal operation of the motor, the following operation is carried out: bs B1+ (Bmr + Bms) (1-B1) C3/2, obtaining a new stalling threshold Bs, and assigning the obtained result to the new stalling threshold Bs;

wherein A1 and B1 are adjustment coefficients, A1 is greater than 0.7, and B1 is greater than 0.7; c4 is a normal threshold coefficient, 1-woven fabric C4 is less than or equal to 1.3, C3 is a locked-rotor threshold coefficient, and 0.5-woven fabric C3 is less than or equal to 0.9.

8. The control method according to any one of claims 1 to 5, wherein the control device comprises a temporary memory or a random access memory, the obtained back electromotive force or back electromotive force related quantity of the motor is stored in the temporary memory or the random access memory, and the temporary memory or the random access memory can store at least 6 groups of data; the step a of processing the back electromotive force or the data of the back electromotive force related quantity of the motor includes removing a maximum value and a minimum value and averaging the rest of data.

9. The control method according to claim 6, characterized in that the control device comprises a temporary memory or a random access memory, the obtained back electromotive force or back electromotive force related quantity of the motor is stored in the temporary memory or the random access memory, and the temporary memory or the random access memory can store at least 6 groups of data; the step a of processing the back electromotive force or the data of the back electromotive force related quantity of the motor includes removing a maximum value and a minimum value and averaging the rest of data.

10. The control method according to claim 7, characterized in that the control device comprises a temporary memory or a random access memory, the obtained back electromotive force or back electromotive force related quantity of the motor is stored in the temporary memory or the random access memory, and the temporary memory or the random access memory can store at least 6 groups of data; the step a of processing the back electromotive force or the data of the back electromotive force related quantity of the motor includes removing a maximum value and a minimum value and averaging the rest of data.

11. The control method according to any one of claims 1 to 5, wherein the control device includes a temporary memory or a random access memory, and the obtained back electromotive force or back electromotive force related quantity of the motor is stored in the temporary memory or the random access memory, and the temporary memory or the random access memory can store at least 6 sets of data; the step a of processing the back electromotive force or the data of the back electromotive force related quantity of the motor includes removing an abnormally large or small value and averaging the remaining data.

12. The control method according to claim 6, characterized in that the control device comprises a temporary memory or a random access memory, the obtained back electromotive force or back electromotive force related quantity of the motor is stored in the temporary memory or the random access memory, and the temporary memory or the random access memory can store at least 6 groups of data; the step a of processing the back electromotive force or the data of the back electromotive force related quantity of the motor includes removing an abnormally large or small value and averaging the remaining data.

13. The control method according to claim 7, characterized in that the control device comprises a temporary memory or a random access memory, the obtained back electromotive force or back electromotive force related quantity of the motor is stored in the temporary memory or the random access memory, and the temporary memory or the random access memory can store at least 6 groups of data; the step a of processing the back electromotive force or the data of the back electromotive force related quantity of the motor includes removing an abnormally large or small value and averaging the remaining data.

14. The control method according to any one of claims 1 to 5, wherein the control device further includes a memory that stores an initial value of the normal threshold, an initial value of a locked-rotor threshold, an initial value of an average value of the motor back electromotive force or the correlation thereof in a normal operation state, and an initial value of an average value of the motor back electromotive force or the correlation thereof in a locked-rotor state, and controls the operation with the initial value of the normal threshold as the normal threshold and the initial value of the locked-rotor threshold as the locked-rotor threshold when the motor starts to operate and the control device does not have the normal threshold and the locked-rotor threshold.

15. The control method according to claim 6, wherein the control device further includes a memory that stores an initial value of the normal threshold, an initial value of a stalling threshold, an initial value of an average value of the motor back electromotive force or the related quantity thereof in a normal operation state, and an initial value of an average value of the motor back electromotive force or the related quantity thereof in a stalling state, and when the motor starts to operate and the control device does not have the normal threshold and the stalling threshold, the initial value of the normal threshold is used as the normal threshold, and the initial value of the stalling threshold is used as the stalling threshold to control the operation.

16. The control method according to claim 7, wherein the control device further includes a memory that stores an initial value of the normal threshold, an initial value of a stalling threshold, an initial value of an average value of the motor back electromotive force or the related quantity thereof in a normal operation state, and an initial value of an average value of the motor back electromotive force or the related quantity thereof in a stalling state, and controls the operation using the initial value of the normal threshold as the normal threshold and the initial value of the stalling threshold as the stalling threshold when the motor starts to operate and the control device does not have the normal threshold and the stalling threshold.

17. A system comprising a control device and a motor, the control device comprising a memory, a temporary memory or a random access memory, the memory storing an initial value of the normal threshold, an initial value of a stalling threshold, an initial value of an average value of the motor back emf or related quantities thereof in a normal running state, an initial value of an average value of the motor back emf or related quantities thereof in a stalling state; the temporary memory or the random access memory is used for storing data of a normal threshold value, a locked rotor threshold value, and the back electromotive force or the related quantity of the back electromotive force of the motor; the system operates according to the control method of any one of claims 1-16.