阅读说明：本技术 一种控制方法及电动阀 (Control method and electric valve ) 是由 不公告发明人 于 2018-07-27 设计创作，主要内容包括：一种控制方法及电动阀,控制方法包括获取步进电机的回滞补偿步数,回滞补偿步数为电动阀改变转动方向时,电动阀由静止到开始转动的过程中步进电机的转动步数；根据电动阀的目标位置与步进电机对应的最大步进计数值获取步进电机对应的理论步进计数值,理论步进计数值为电动阀由开始转动至到达目标位置的过程中步进电机所需的步进计数值；根据回滞补偿步数与理论步进计数值获取步进电机对应的目标步进计数值,目标步进计数值为电动阀由静止至到达目标位置的过程中步进电机所需的步进计数值；根据目标步进计数值控制电动阀向目标位置转动。这样,改善了电动阀的实际位置受回滞现象影响的问题,提高了对电动阀的控制过程的准确性。(A control method and electric valve, the control method includes obtaining the compensation step number of hysteresis of the stepping motor, the compensation step number of hysteresis is when the electric valve changes the rotational direction, the electric valve is from resting to the rotational step number of the stepping motor in the course of starting to rotate; obtaining a theoretical step count value corresponding to the stepping motor according to the target position of the electric valve and the maximum step count value corresponding to the stepping motor, wherein the theoretical step count value is a step count value required by the stepping motor in the process that the electric valve rotates from the beginning to reach the target position; acquiring a target step count value corresponding to the stepping motor according to the hysteresis compensation step number and the theoretical step count value, wherein the target step count value is a step count value required by the stepping motor in the process that the electric valve is stopped to reach the target position; and controlling the electric valve to rotate to the target position according to the target step count value. Therefore, the problem that the actual position of the electric valve is influenced by the hysteresis phenomenon is solved, and the accuracy of the control process of the electric valve is improved.)

1. A control method capable of controlling an electrically operated valve, characterized by comprising:

obtaining the hysteresis compensation step number of a stepping motor, wherein the hysteresis compensation step number is the rotation step number of the stepping motor in the process that the electric valve starts to rotate from rest when the electric valve changes the rotation direction;

obtaining a theoretical step count value corresponding to the stepping motor according to the target position of the electric valve and the maximum step count value corresponding to the stepping motor, wherein the theoretical step count value is a step count value required by the stepping motor in the process that the electric valve rotates from the beginning to the target position;

acquiring a target step count value corresponding to the stepping motor according to the hysteresis compensation step number and the theoretical step count value, wherein the target step count value is a step count value required by the stepping motor in the process that the electric valve is stopped to reach the target position;

and controlling the electric valve to rotate to the target position according to the target step count value.

2. The control method according to claim 1, wherein the obtaining the number of hysteresis compensation steps of the stepping motor comprises:

and controlling the electric valve to change the rotation direction, and acquiring the hysteresis compensation step number of the stepping motor according to the rotation speed of the electric valve.

3. The control method according to claim 1, wherein the obtaining a target step count value corresponding to the stepping motor according to the hysteresis compensation step number and the theoretical step count value comprises:

and if the absolute value of the theoretical step count value is larger than the hysteresis compensation step number, acquiring a target step count value corresponding to the stepping motor according to the rotation direction of the stepping motor, the hysteresis compensation step number and the theoretical step count value.

4. The control method according to claim 3, wherein the obtaining a target step count value corresponding to the stepping motor according to the rotation direction of the stepping motor, the hysteresis compensation step number, and the theoretical step count value comprises:

if the stepping motor rotates forwards, taking the sum of the theoretical stepping count value and the hysteresis compensation step number as the target stepping count value corresponding to the stepping motor;

and if the stepping motor rotates reversely, taking the difference value between the theoretical step count value and the hysteresis compensation step number as a target step count value corresponding to the stepping motor.

5. The control method according to claim 1, before the obtaining a theoretical step count value corresponding to the stepping motor according to the maximum step count value corresponding to the stepping motor according to the target position of the electric valve, further comprising:

and acquiring the target position of the electric valve according to the target setting parameters in a table searching mode, wherein the table comprises the corresponding relation between the position of the electric valve and the setting parameters.

6. The method of claim 5, wherein the electrically operated valve comprises a water valve, the target setting parameter comprises a target flow rate, and the table comprises a correspondence between a position of the water valve and a flow rate.

7. The control method according to claim 1, further comprising, after the controlling the electric valve to rotate to the target position according to the target step count value:

acquiring an actual step count value of the stepping motor, wherein the actual step count value is the actual step count value of the stepping motor in the process that the electric valve is stopped to reach the target position;

and judging whether to control the electric valve to rotate to the target position or not according to the absolute value of the target step count value and the absolute value of the actual step count value.

8. The control method according to claim 7, wherein the determining whether to control the electric valve to rotate to the target position based on the absolute value of the target step count value and the absolute value of the actual step count value includes:

if the absolute value of the target step count value is larger than the absolute value of the actual step count value, controlling the electric valve to rotate along the original rotation direction at the target position;

and if the absolute value of the target step counting value is smaller than the absolute value of the actual step counting value, controlling the electric valve to rotate to the target position along the reverse direction of the original rotation direction.

9. An electrically operated valve, comprising a valve plate and a stepping motor, wherein the stepping motor drives the valve plate to operate, and the stepping motor operates according to a control method, and the control method comprises the control method of any one of claims 1 to 8.

10. The electric valve of claim 9, wherein the position of the valve sheet is obtained by a method comprising:

obtaining the hysteresis compensation step number of a stepping motor, wherein the hysteresis compensation step number is the rotation step number of the stepping motor in the process that the electric valve starts to rotate from rest when the electric valve changes the rotation direction;

acquiring the real-time rotating step number of the stepping motor;

starting step counting and acquiring a real-time step counting value when the real-time rotation step number is equal to the hysteresis compensation step number;

and acquiring the position of the valve plate according to the real-time step count value and the maximum step count value corresponding to the step motor.

11. The electrically actuated valve of claim 10, wherein starting a step count when the number of real-time rotational steps equals the number of hysteresis compensation steps and obtaining a real-time step count value comprises:

starting step counting when the real-time rotation step number is equal to the hysteresis compensation step number;

and acquiring the real-time stepping count value according to the rotation direction of the stepping motor.

Technical Field

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

Background

The electrically operated valve generally includes a controller, a stepping motor and a valve body, the controller sends a driving signal to the stepping motor to control the stepping motor to rotate, the stepping motor drives the valve body of the electrically operated valve to rotate, so that the valve body reaches a corresponding opening degree, the electrically operated valve may be, for example, a vehicular water valve, and the adjustment of the flow rate of the coolant can be realized by adjusting the position of the valve body in the vehicular water valve.

The electric valve has hysteresis phenomenon due to the arrangement mode of a mechanical structure, namely, the valve block on the gear output shaft is static when the stepping motor switches forward and backward, and the valve block of the electric valve starts to rotate after the stepping motor rotates for a certain angle, so that the actual position of the electric valve is influenced by the hysteresis phenomenon, the electric valve cannot accurately reach the required target position, and the accuracy of the control process of the electric valve is low. At present, the problem that the actual position of the electric valve is affected by the hysteresis phenomenon can be improved by improving the internal mechanical structure of the electric valve, but the method has higher requirements on the material and the specific structure of the mechanical structure, and the development and production cost of the electric valve is increased.

Disclosure of Invention

In view of this, the embodiment of the present invention provides a control method and an electrically operated valve, which improve the problem that the actual position of the electrically operated valve is affected by the hysteresis phenomenon, improve the accuracy of the control process of the electrically operated valve, reduce the requirements on the mechanical structure material and the specific structure and value, and reduce the development and production costs of the electrically operated valve, compared with the prior art in which the mechanical structure of the electrically operated valve is changed.

In a first aspect, an embodiment of the present invention provides a control method, capable of controlling an electrically operated valve, where the control method includes:

obtaining the hysteresis compensation step number of a stepping motor, wherein the hysteresis compensation step number is the rotation step number of the stepping motor in the process that the electric valve starts to rotate from rest when the electric valve changes the rotation direction;

obtaining a theoretical step count value corresponding to the stepping motor according to the target position of the electric valve and the maximum step count value corresponding to the stepping motor, wherein the theoretical step count value is a step count value required by the stepping motor in the process that the electric valve rotates from the beginning to the target position;

acquiring a target step count value corresponding to the stepping motor according to the hysteresis compensation step number and the theoretical step count value, wherein the target step count value is a step count value required by the stepping motor in the process that the electric valve is stopped to reach the target position;

and controlling the electric valve to rotate to the target position according to the target step count value.

In a second aspect, an embodiment of the present invention further provides an electrically operated valve, where the electrically operated valve includes a step motor and a valve plate, the step motor drives the valve plate to operate, the step motor operates according to a control method, and the control method includes the control method of the first aspect.

The method for acquiring the position of the valve plate comprises the following steps:

obtaining the hysteresis compensation step number of a stepping motor, wherein the hysteresis compensation step number is the rotation step number of the stepping motor in the process that the electric valve starts to rotate from rest when the electric valve changes the rotation direction;

acquiring the real-time rotating step number of the stepping motor;

starting step counting and acquiring a real-time step counting value when the real-time rotation step number is equal to the hysteresis compensation step number;

and acquiring the position of the valve plate according to the real-time step count value and the maximum step count value corresponding to the step motor.

The embodiment of the invention provides a control method and an electric valve, which comprises the steps of obtaining the hysteresis compensation step number of a stepping motor, wherein the hysteresis compensation step number is the rotation step number of the stepping motor in the process that the electric valve starts to rotate from rest when the electric valve changes the rotation direction; obtaining a theoretical step count value corresponding to the stepping motor according to the target position of the electric valve and the maximum step count value corresponding to the stepping motor, wherein the theoretical step count value is a step count value required by the stepping motor in the process that the electric valve rotates from the beginning to reach the target position; acquiring a target step count value corresponding to the stepping motor according to the hysteresis compensation step number and the theoretical step count value, wherein the target step count value is a step count value required by the stepping motor in the process that the electric valve is stopped to reach the target position; and controlling the electric valve to rotate to the target position according to the target step count value. The method has the advantages that the hysteresis compensation steps are utilized to monitor the rotation steps of the stepping motor in the process of starting rotation from rest of the electric valve when the rotation direction of the electric valve is changed, the target stepping counting value corresponding to the stepping motor is obtained according to the hysteresis compensation steps and the theoretical stepping counting value, the electric valve is controlled to rotate to the target position according to the target stepping counting value, the problem that the actual position of the electric valve is affected by hysteresis is solved, the accuracy of the control process of the electric valve is improved, the requirements on mechanical structure materials and specific structures and values are reduced compared with the method for changing the mechanical structure of the electric valve in the prior art, and the development and production cost of the electric valve is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present invention, the drawings needed to be used in the description of the embodiments or the background art will be briefly introduced below, and it is obvious that the drawings in the following description are schematic diagrams of some embodiments of the present invention, and for those skilled in the art, other solutions can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic flow chart of a control method according to an embodiment of the present invention;

FIG. 2 is a graph of the position of an electrically operated water valve versus flow rate according to an embodiment of the present invention;

FIG. 3 is a schematic flow chart of another control method according to an embodiment of the present invention;

fig. 4 is a schematic flow chart of a method for acquiring a position of a valve plate according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described through embodiments with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a schematic flowchart of a control method according to an embodiment of the present invention, where the control method may be applied to a scenario where an electric valve is required to perform control, and the control method may be executed by a control system of the electric valve, where the control system may be executed in a software and/or hardware manner. The control method comprises the following steps:

s101, obtaining the hysteresis compensation step number of the stepping motor, wherein the hysteresis compensation step number is the rotation step number of the stepping motor in the process that the electric valve starts to rotate from rest when the electric valve changes the rotation direction.

The electric valve has hysteresis phenomenon due to the arrangement mode of a mechanical structure, namely, a valve sheet on a gear output shaft is static at the initial stage of forward and reverse rotation switching of the stepping motor, and the electric valve starts to rotate after the stepping motor rotates for a certain angle. The electric valve is influenced by the hysteresis phenomenon, when the electric valve changes the rotation direction, the electric valve needs a period of time from rest to start to rotate, and the hysteresis compensation step number of the stepping motor is the rotation step number of the stepping motor in the process that the electric valve changes the rotation direction from rest to start to rotate.

For example, the hysteresis compensation step number of the stepping motor may be obtained by first controlling the electric valve to change the rotation direction, may control the electric valve to change from forward rotation to reverse rotation, may also control the electric valve to change from reverse rotation to forward rotation, and may be set according to a specific requirement on the rotation direction of the electric valve. And acquiring the hysteresis compensation step number of the stepping motor according to the rotation speed of the electric valve, namely detecting the stage from the standstill of the electric valve, namely the rotation speed is zero, to the start of the rotation of the electric valve, namely the rotation speed of the electric valve is changed into a non-zero value, and acquiring the rotation step number of the stepping motor in the stage, namely the hysteresis compensation step number.

And S102, acquiring a theoretical step count value corresponding to the stepping motor according to the target position of the electric valve and the maximum step count value corresponding to the stepping motor, wherein the theoretical step count value is a step count value required by the stepping motor in the process that the electric valve rotates from the starting position to the target position.

For example, before the theoretical step count value corresponding to the stepping motor is obtained according to the maximum step count value corresponding to the stepping motor and the target position of the electric valve, the target position of the electric valve may be obtained according to a target setting parameter by means of table lookup, where the table includes a corresponding relationship between the position of the electric valve and the setting parameter. For example, the electrically operated valve may include an electrically operated water valve, the step motor rotates to drive the water valve to rotate, the step motor rotates in a forward direction, the electrically operated water valve clockwise runs to a first water valve endpoint, and a water valve position corresponding to the first water valve endpoint is 100%; the stepping motor rotates reversely, the electric water valve rotates anticlockwise to a second water valve end point, and the position of the water valve corresponding to the second water valve end point is 0%. The target setting parameter includes a target flow rate of the electrically operated water valve, and the table may include a correspondence between a position of the electrically operated valve and the flow rate. The electric water valve comprises a valve plate and a stepping motor, wherein the stepping motor drives the valve plate to operate, and the stepping motor operates according to a preset control method.

Fig. 2 is a graph showing the relationship between the position and the flow rate of the electrically operated water valve according to the embodiment of the present invention. As shown in fig. 2, the abscissa represents the position of the valve plate, the unit is%, the position of the valve plate can be understood as the opening degree of the electric water valve, the ordinate represents the flow rate of the electric water valve, the unit is%, a curve 1 in fig. 2 is a relation curve corresponding to the position and the flow rate of the valve plate when the water valve rotates in the forward direction, a curve 2 is a relation curve corresponding to the position and the flow rate of the valve plate when the electric water valve rotates in the reverse direction, and the target position of the valve plate can be obtained according to the target set flow rate, corresponding to the relation curve of the position and the flow rate.

It should be noted that fig. 2 retains the influence factor of the hysteresis phenomenon, referring to curve 1, the flow rate of the electric water valve starts to increase when the electric water valve transitions from reverse rotation to forward rotation, and referring to curve 2, the flow rate of the electric water valve begins to decrease when the electric water valve transitions from forward rotation to reverse rotation, and the flow rate of the electric water valve starts to decrease when the electric water valve transitions from 88% to 94%. It should be noted that, in the above embodiments, the electrically operated valve is merely used as an electrically operated water valve, and the specific type of the electrically operated valve is not limited in the embodiments of the present invention.

After the target position of the electric valve is obtained, a theoretical step count value corresponding to the stepping motor can be obtained according to the target position of the electric valve and the maximum step count value corresponding to the stepping motor, and the maximum step count value corresponding to the stepping motor is equal to the process that the position of the electric valve is changed from 0% to 100%The number of steps of rotation of the middle stepping motor. The theoretical step count value corresponding to the step motor is the step count value required by the step motor in the process that the electric valve rotates from the beginning to the target position of the electric valve, the step count value is the theoretical value, and the target position of the electric valve can be set to be T_openIf the maximum step count value corresponding to the stepping motor is MaxCount, the theoretical step count value TFCount corresponding to the stepping motor satisfies the following calculation formula:

TFCount＝T_open·MaxCount

accordingly, the theoretical step count value corresponding to the stepping motor is obtained according to the maximum step count value corresponding to the stepping motor and the target position of the electric valve is obtained according to the target setting parameter in a table lookup manner, the setting parameter and the target position of the electric valve are not necessarily in a linear relationship, for example, a relationship curve shown in fig. 2 is in an S shape, the position and the flow rate of the water valve are not in a linear relationship, and compared with the case that the target position of the electric valve is directly obtained according to the target setting parameter and the linear relationship, the theoretical step count value corresponding to the stepping motor can be more accurately obtained according to the target position of the electric valve and the maximum step count value corresponding to the stepping motor.

And S103, acquiring a target step count value corresponding to the stepping motor according to the hysteresis compensation step number and the theoretical step count value, wherein the target step count value is a step count value required by the stepping motor in the process that the electric valve is stopped to reach the target position.

For example, the relationship between the absolute value of the theoretical step count value corresponding to the obtained stepping motor and the hysteresis compensation step number of the stepping motor may be determined first, and since the stepping motor rotates one step in the forward direction, the step count value increases by 1, the stepping motor rotates one step in the direction, the step count value decreases by 1, and after the zero point position is calibrated, the stepping motor rotates forward or backward relative to the zero point position so that the step count value may be a positive value or a negative value, the absolute value of the theoretical step count value is defined herein.

When the electric valve changes the rotation direction, the electric valve starts to rotate from the rest state to the rotation start process, if the absolute value of the theoretical step counting value is larger than the hysteresis compensation step number, the electric valve can be judged to start to rotate, and if the absolute value of the theoretical step counting value is smaller than or equal to the hysteresis compensation step number, the electric valve can be judged not to start to rotate. And when the absolute value of the theoretical step count value is greater than the hysteresis compensation value, acquiring a target step count value corresponding to the stepping motor according to the rotation direction of the stepping motor, the hysteresis compensation step number and the theoretical step count value.

If the stepping motor rotates forwards, the sum of the theoretical step count value and the hysteresis compensation step number is used as a target step count value corresponding to the stepping motor, namely when the stepping motor rotates forwards, the sum of the theoretical step count value and the hysteresis compensation step number is used as a step count value required by the stepping motor in the process of starting to rotate the electric valve from the beginning to the target position, the value is a positive value, and when the electric valve changes the rotating direction, the sum of the theoretical step count value and the hysteresis compensation step number is used as a step count value required by the stepping motor in the process of starting to rotate the electric valve from the rest to the target position, the value is a positive value, so that the step number which the stepping motor actually needs to rotate forwards in the process of stopping the electric valve to reach the target position is accurately obtained.

If the stepping motor rotates reversely, the difference value between the theoretical step count value and the hysteresis compensation step number is used as a target step count value corresponding to the stepping motor, namely when the stepping motor rotates reversely, the step count value required by the stepping motor in the process of starting to rotate the electric valve to reach the target position is a negative value, when the electric valve changes the rotating direction, the step count value required by the stepping motor in the process of starting to rotate the electric valve from rest to reach the target position is a positive value, the difference value is used as the step count value required by the stepping motor in the process of stopping the electric valve to reach the target position, and the difference value is a negative value, so that the step count which the stepping motor actually should rotate reversely in the process of stopping the electric valve to reach the target position is accurately obtained.

And S104, controlling the electric valve to rotate to the target position according to the target step counting value.

The electric valve is controlled to rotate to a target position according to a target stepping counting value corresponding to the stepping motor, which is obtained by calculating the hysteresis compensation step number and the theoretical stepping counting value, the hysteresis compensation step number is utilized to realize the monitoring of the rotation step number of the stepping motor in the process of starting rotation from rest of the electric valve when the rotation direction of the electric valve is changed, the problem that the actual position of the electric valve is influenced by the hysteresis phenomenon is solved, the accuracy of the control process of the electric valve is improved, the requirements on mechanical structure materials and specific structures and values are reduced compared with the change of the mechanical structure of the electric valve in the prior art, and the development and production cost of the electric valve are reduced.

Fig. 3 is a schematic flowchart of another control method according to an embodiment of the present invention. On the basis of the control method shown in fig. 1, after the electric valve is controlled to rotate to the target position according to the target step count value, the actual step count value of the stepping motor can be obtained, wherein the actual step count value is the actual step count value of the stepping motor in the process that the electric valve is stopped to reach the target position; and judging whether to control the electric valve to rotate to the target position or not according to the target step count value and the actual step count value. As shown in fig. 3, the control method includes:

s201, obtaining the hysteresis compensation step number of the stepping motor, wherein the hysteresis compensation step number is the rotation step number of the stepping motor in the process that the electric valve starts to rotate from rest when the electric valve changes the rotation direction.

S202, obtaining a theoretical step count value corresponding to the stepping motor according to the target position of the electric valve and the maximum step count value corresponding to the stepping motor, wherein the theoretical step count value is a step count value required by the stepping motor in the process that the electric valve rotates from the starting position to the target position.

And S203, acquiring a target step count value corresponding to the stepping motor according to the hysteresis compensation step number and the theoretical step count value, wherein the target step count value is a step count value required by the stepping motor in the process that the electric valve is stopped to reach the target position.

And S204, controlling the electric valve to rotate to the target position according to the target step count value.

And S205, acquiring an actual step count value of the stepping motor, wherein the actual step count value is the actual step count value of the stepping motor in the process that the electric valve is stopped to reach the target position.

And after the electric valve is controlled to rotate to the target position according to the target step count value, acquiring an actual step count value of the stepping motor, wherein the actual step count value is the actual step count value of the stepping motor in the process that the electric valve is stopped to reach the target position. The electric valve comprises a microcontroller, the microcontroller can control the rotation parameters of the stepping motor, the microcontroller controls the control process of the stepping motor in an open loop mode, and the microcontroller can directly acquire the actual stepping count value of the stepping motor in the process that the electric valve is static to reach the target position according to the driving signal output to the stepping motor.

And S206, judging whether to control the electric valve to rotate to the target position or not according to the absolute value of the target step counting value and the absolute value of the actual step counting value.

Judging the magnitude relation between the absolute value of the target step counting value and the absolute value of the actual step counting value, and if the absolute value of the target step counting value is larger than the absolute value of the actual step counting value, controlling the electric valve to rotate along the target position in the original rotating direction until the target step counting value corresponding to the stepping motor is equal to the actual step counting value corresponding to the stepping motor; and if the absolute value of the target step counting value is smaller than the absolute value of the actual step counting value, controlling the electric valve to rotate to the target position along the reverse direction of the original rotating direction until the target step counting value corresponding to the stepping motor is equal to the actual step counting value corresponding to the stepping motor.

After the electric valve is controlled to rotate to the target position according to the target step counting value, whether the electric valve is controlled to rotate to the target position is judged according to the absolute value of the target step counting value and the absolute value of the actual step counting value, and if the absolute value of the target step counting value is larger than the absolute value of the actual step counting value, the electric valve is controlled to rotate to the target position along the original rotating direction; if the absolute value of the target stepping counting value is smaller than the absolute value of the actual stepping counting value, the electric valve is controlled to rotate to the target position along the reverse direction of the original rotating direction, the problem that the actual position of the electric valve is influenced by the hysteresis phenomenon is solved, the accuracy of the control process of the electric valve is improved, meanwhile, the compensation of the actual stepping counting value corresponding to the stepping motor is realized, the difference between the actual position of the electric valve and the target position of the electric valve is reduced, and the accuracy of the control process of the electric valve is further improved.

The embodiment of the invention also provides the electric valve, the electric valve comprises a valve plate and a stepping motor, the stepping motor drives the valve plate to operate, the stepping motor operates according to the control method, and the control method can comprise the control method in the embodiment.

Fig. 4 is a schematic flow chart of a method for acquiring a position of a valve plate according to an embodiment of the present invention, where the method for acquiring a position of a valve plate can be applied to a scene where the position of the valve plate needs to be acquired, and can be executed by an acquisition system of the position of the valve plate, and the system can be executed in a software and/or hardware manner. As shown in fig. 4, the position acquisition method includes:

s301, obtaining the hysteresis compensation step number of the stepping motor, wherein the hysteresis compensation step number is the rotation step number of the stepping motor in the process that the electric valve starts to rotate from rest when the electric valve changes the rotation direction.

When the stepping motor is in the initial stage of forward and reverse rotation switching, the electric valve starts to rotate after the stepping motor rotates for a certain angle. The electric valve is influenced by the hysteresis phenomenon, when the electric valve changes the rotation direction, the electric valve needs a period of time from rest to start to rotate, and the hysteresis compensation step number of the stepping motor is the rotation step number of the stepping motor in the process that the electric valve changes the rotation direction from rest to start to rotate.

The electric valve can be controlled to change the rotation direction, the hysteresis compensation step number of the stepping motor is obtained according to the rotation speed of the electric valve, namely the rotation speed of the electric valve is detected to be zero from the static state to the stage when the electric valve starts to rotate, namely the rotation speed of the electric valve starts to be changed into a non-zero value, and the rotation step number of the stepping motor in the stage is obtained and is the hysteresis compensation step number.

And S302, acquiring the real-time rotation step number of the stepping motor.

The method comprises the steps of obtaining the real-time rotating step number of a stepping motor, namely obtaining the step number of the stepping motor rotating from rest to the current moment, similarly, controlling the stepping motor to rotate by a microcontroller in an electric valve, wherein the control process of the stepping motor by the microcontroller is an open-loop control process, and the microcontroller can directly obtain the real-time rotating step number of the stepping motor according to a driving signal output to the stepping motor.

And S303, starting step counting when the real-time rotation step number is equal to the hysteresis compensation step number and acquiring a real-time step counting value.

And starting step counting when the real-time rotation step number is equal to the hysteresis compensation step number, and acquiring a real-time step counting value according to the rotation direction of the stepping motor. When the real-time rotation step number is equal to the hysteresis compensation step number, the electric valve starts to rotate, the stepping counting is started at the moment, the rotation direction of the stepping motor is detected, and if the stepping motor rotates in the forward direction, the stepping real-time stepping counting value is added by 1 when the stepping motor rotates for one step; if the stepping motor rotates reversely, the real-time stepping counting value is subtracted by 1 every time the stepping motor rotates one step.

S304, acquiring the position of the valve plate according to the real-time step count value and the maximum step count value corresponding to the step motor.

The position of the electric valve is obtained according to the real-time step count value and the maximum step count value corresponding to the step motor, the maximum step count value corresponding to the step motor is the rotation step number of the step motor in the process that the position of the electric valve is changed from 0% to 100%, the maximum step count value corresponding to the step motor can be set to be MaxCount, the real-time step count value corresponding to the step motor is FCount, and then the position Pos of the electric valve meets the following formula:

by obtaining the hysteresis compensation step number of the stepping motor, the hysteresis compensation step number is the rotation step number of the stepping motor in the process that the electric valve starts to rotate from rest when the electric valve changes the rotation direction; acquiring the real-time rotation step number of a stepping motor; starting step counting and acquiring a real-time step counting value when the real-time rotation step number is equal to the hysteresis compensation step number; and acquiring the position of the electric valve according to the real-time step count value and the maximum step count value corresponding to the step motor. When the real-time rotation step number of the stepping motor is equal to the hysteresis compensation step number, the stepping counting is started, namely, the stepping counting is started to obtain a real-time stepping counting value when the electric valve starts to rotate, and the position of the electric valve is obtained according to the real-time stepping counting value, so that the influence of the hysteresis phenomenon on the position obtaining process of the electric valve is avoided, and the accuracy of the position obtaining of the electric valve is improved.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments illustrated herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.