Motor control method and device, motor and readable storage medium

文档序号：1878026 发布日期：2021-11-23 浏览：4次中文

阅读说明：本技术 电机的控制方法、装置、电机和可读存储介质 (Motor control method and device, motor and readable storage medium ) 是由彭国彬于 2021-08-31 设计创作，主要内容包括：本发明提供了一种电机的控制方法、装置、电机和可读存储介质。其中,电机的控制方法包括：在电机从开环运行阶段切换至闭环运行阶段过程中,获取电机处于开环运行阶段下,d-q坐标系的第一电流幅值和第一电压幅值；确定电机的开环位置角度和闭环位置角度之间的角度偏差；根据角度偏差、第一电流幅值和第一电压幅值,设定电机处于闭环运行阶段下,d-q坐标系的第二电流幅值和第二电压幅值。从而在切换过程中,给定电压和给定电流的幅值和绝对角度都不会发生突变,有效解决开、闭环切换时由于开、闭环估算角度不一致导致切换时电流大小和相位发生突变的问题,实现开环运行阶段和闭环运行阶段的平稳切换过渡。(The invention provides a control method and device of a motor, the motor and a readable storage medium. The control method of the motor comprises the following steps: in the process of switching the motor from the open-loop operation stage to the closed-loop operation stage, acquiring a first current amplitude and a first voltage amplitude of a d-q coordinate system when the motor is in the open-loop operation stage; determining an angular deviation between an open-loop position angle and a closed-loop position angle of the motor; and setting a second current amplitude and a second voltage amplitude of the d-q coordinate system when the motor is in a closed-loop operation stage according to the angle deviation, the first current amplitude and the first voltage amplitude. Therefore, in the switching process, the amplitude and the absolute angle of the given voltage and the given current cannot be suddenly changed, the problem that the current magnitude and the phase are suddenly changed during switching due to the fact that estimated angles of the open loop and the closed loop are inconsistent during switching of the open loop and the closed loop is effectively solved, and stable switching transition of an open loop operation stage and a closed loop operation stage is achieved.)

1. A method of controlling a motor, comprising:

in the process of switching the motor from an open-loop operation stage to a closed-loop operation stage, acquiring a first current amplitude and a first voltage amplitude of a d-q coordinate system of the motor in the open-loop operation stage;

determining an angular deviation between an open-loop position angle and a closed-loop position angle of the motor;

and setting a second current amplitude and a second voltage amplitude of the d-q coordinate system of the motor in the closed-loop operation stage according to the angle deviation, the first current amplitude and the first voltage amplitude.

2. The method of claim 1, wherein the setting a second current magnitude of a d-q coordinate system of the motor in a closed-loop operation phase according to the angular deviation and the first current magnitude comprises:

taking the product of the cosine value of the angle deviation and the first current amplitude as a d-axis current amplitude in the second current amplitude;

and taking the product of the sine value of the angle deviation and the first current amplitude value as the q-axis current amplitude value in the second current amplitude value.

3. The method of claim 1, wherein said setting a second voltage magnitude of a d-q coordinate system of said motor in a closed-loop operating phase based on said angular deviation and said first voltage magnitude comprises:

setting a d-axis voltage amplitude in the second voltage amplitude according to a product of a d-axis voltage amplitude in the first voltage amplitude and a cosine value of the angle deviation and a product of a q-axis voltage amplitude in the first voltage amplitude and a sine value of the angle deviation;

and setting a q-axis voltage amplitude in the second voltage amplitude according to a product of a d-axis voltage amplitude in the first voltage amplitude and a sine value of the angle deviation and a product of a q-axis voltage amplitude in the first voltage amplitude and a cosine value of the angle deviation.

4. The method of controlling a motor of claim 1, wherein said determining an angular offset between an open-loop position angle and a closed-loop position angle of the motor comprises:

determining the open-loop position angle according to the rotating speed of the motor;

determining a closed loop position angle according to the flux linkage information of the motor and the phase-locked loop;

determining a difference between the open-loop position angle and the closed-loop position angle as the angular deviation.

5. The control method of the motor according to any one of claims 1 to 4, characterized by further comprising:

controlling the rotating speed of the motor to be kept within a preset rotating speed range;

controlling the current amplitude of the motor to be reduced to an amplitude threshold value;

timing a duration that the current amplitude is less than or equal to the amplitude threshold;

and controlling the motor to enter the closed-loop operation stage based on the duration being greater than or equal to the preset duration.

6. The method of controlling the motor of claim 5, wherein the controlling the current magnitude of the motor to be reduced to a magnitude threshold comprises:

and controlling the current amplitude to reduce for multiple times according to the preset offset.

7. The control method of the motor according to any one of claims 1 to 4, characterized by further comprising:

responding to a starting instruction of the motor, and acquiring a current amplitude of the motor;

controlling the motor to enter the open-loop operation stage according to the current amplitude, and acquiring the rotating speed of the motor;

and controlling the motor to be switched from the open-loop operation stage to the closed-loop operation stage based on the rotating speed of the motor being greater than or equal to the preset rotating speed.

8. A control device of a motor, characterized by comprising:

the acquisition module is used for acquiring a first current amplitude and a first voltage amplitude of a d-q coordinate system of the motor in an open-loop operation stage in the process of switching the motor from the open-loop operation stage to a closed-loop operation stage;

a determination module for determining an angular deviation between an open-loop position angle and a closed-loop position angle of the motor;

and the switching module is used for setting a second current amplitude and a second voltage amplitude of the d-q coordinate system of the motor in the closed-loop operation stage according to the angle deviation, the first current amplitude and the first voltage amplitude.

9. The control device of an electric motor according to claim 8,

the switching module is further configured to use a product of a cosine value of the angular deviation and the first current amplitude as a d-axis current amplitude in the second current amplitude;

and taking the product of the sine value of the angle deviation and the first current amplitude value as the q-axis current amplitude value in the second current amplitude value.

10. The control device of an electric motor according to claim 8,

the switching module is further configured to set a d-axis voltage amplitude in the second voltage amplitude according to a product of a d-axis voltage amplitude in the first voltage amplitude and a cosine value of the angle deviation, and a product of a q-axis voltage amplitude in the first voltage amplitude and a sine value of the angle deviation;

11. The control device of an electric motor according to claim 8,

the determining module is further used for determining the open-loop position angle according to the rotating speed of the motor;

determining a closed loop position angle according to the flux linkage information of the motor and the phase-locked loop;

determining a difference between the open-loop position angle and the closed-loop position angle as the angular deviation.

12. The control device of the motor according to any one of claims 8 to 10, further comprising:

the control module is used for controlling the rotating speed of the motor to be kept within a preset rotating speed range;

controlling the current amplitude of the motor to be reduced to an amplitude threshold value;

the timing module is used for timing the duration that the current amplitude is smaller than or equal to the amplitude threshold;

the control module is further used for controlling the motor to enter the closed-loop operation stage based on the duration being greater than or equal to a preset duration.

13. The control device of an electric motor according to claim 12,

the control module is further configured to control the current amplitude to decrease for multiple times according to a preset offset.

14. The control device of the motor according to any one of claims 8 to 10,

the obtaining module is further used for responding to a starting instruction of the motor and obtaining a current amplitude of the motor;

the control device of the motor further includes:

the starting module is used for controlling the motor to enter the open-loop operation stage according to the current amplitude;

the acquisition module is also used for acquiring the rotating speed of the motor;

the switching module is further used for controlling the motor to be switched from the open-loop operation stage to the closed-loop operation stage based on the fact that the rotating speed of the motor is greater than or equal to a preset rotating speed.

15. An electric machine, comprising:

a memory storing programs or instructions;

a processor implementing the control method of the electric machine of any one of claims 1 to 7 when executing the program or the instructions.

16. A readable storage medium on which a program or instructions are stored, characterized in that the program or instructions, when executed by a processor, perform a control method of an electric machine according to any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of motor control, in particular to a motor control method, a motor control device, a motor and a readable storage medium.

Background

In the related art, most of motors (including compressors and fans) used in home appliances are controlled by a position-sensorless control method, and are usually started in an open-loop, a closed-loop manner. When the ring is opened, the motor is directly dragged to rotate through the open ring at a given angle, and only a current ring and no rotating speed ring exist at the moment. When the motor establishes a certain back electromotive force, the motor is directly switched into closed-loop control, and the position and the rotating speed of a motor rotor are estimated by a position-sensorless control method in the closed-loop stage. Because the rotor position estimation methods adopted in the open-loop stage and the closed-loop stage are different, when the open loop is switched into the closed loop, the estimated angle and speed are inevitably subjected to sudden change, the actual control effect is influenced, and the starting stability and reliability of the motor are further influenced.

Disclosure of Invention

The present invention is directed to solving or improving at least one of the technical problems of the prior art or the related art.

To this end, a first aspect of the invention provides a control method of an electric machine.

The second aspect of the invention also provides a control device of the motor.

The third aspect of the invention also provides an electric machine.

The fourth aspect of the present invention also provides a readable storage medium.

In view of this, a first aspect of the present invention provides a method for controlling a motor, including obtaining a first current amplitude and a first voltage amplitude of a d-q coordinate system of the motor in an open-loop operation stage during a process of switching the motor from the open-loop operation stage to a closed-loop operation stage; determining an angular deviation between an open-loop position angle and a closed-loop position angle of the motor; and setting a second current amplitude and a second voltage amplitude of the d-q coordinate system of the motor in the closed-loop operation stage according to the angle deviation, the first current amplitude and the first voltage amplitude.

According to the control method of the motor, in the starting process of the motor, the given current is taken as the final target current of the motor to be operated in an open loop mode, and when the motor reaches a certain rotating speed and establishes a certain back electromotive force, the motor needs to be switched to be operated in a closed loop mode, so that the motor can be accurately controlled through control feedback.

Specifically, in the process of switching the motor from the open-loop operation stage to the closed-loop operation stage, namely the open-loop-closed-loop switching stage, a first current amplitude and a first voltage amplitude of a d-q coordinate system (two-phase rotation coordinate system), namely maximum values of current and voltage, are obtained when the motor is in the open-loop operation stage. Wherein the first current amplitude includes a component of a d-axis (direct axis) current amplitude and a component of a q-axis (quadrature axis) current amplitude in the open loop, and likewise, the first voltage amplitude includes a component of a d-axis (direct axis) voltage amplitude and a q-axis (quadrature axis) voltage amplitude in the open loop. Estimating a rotor position angle (open-loop position angle) of the motor in an open-loop operation stage and a rotor position angle (closed-loop position angle) of the motor in a closed-loop operation stage, determining a second current amplitude of the motor in the closed-loop operation stage by using an angle deviation between the open-loop position angle and the closed-loop position angle and the first current amplitude, and determining a second voltage amplitude of the motor in the closed-loop operation stage by using the angle deviation between the open-loop position angle and the closed-loop position angle and the first voltage amplitude. Therefore, the difference of rotor position estimation adopted in the open-loop and closed-loop operation stages is fully considered, and when the switching stage begins, the first current amplitude and the first voltage amplitude can be switched to the d axis and the q axis of the closed-loop d-q coordinate system from the d axis and the q axis of the open-loop d-q coordinate system, namely, the given current and the given voltage under the open-loop d-q coordinate system are projected onto the closed-loop d-q coordinate system according to the angle deviation.

According to the motor control method provided by the invention, the second current amplitude and the second voltage amplitude are obtained by conversion according to the proportion of the first current amplitude and the first voltage amplitude, only a reference coordinate system, namely coordinate projection, is switched in the switching stage process, and the amplitude (current upper limit value) and the absolute angle of the given voltage and the given current cannot be suddenly changed, so that the problem that the current magnitude and the phase suddenly change in switching due to the inconsistency of the open-loop estimation angle and the closed-loop estimation angle in the open-loop switching and closed-loop switching is effectively solved, the stable switching transition of the open-loop operation stage and the closed-loop operation stage is realized, the problem that the motor cannot stably operate due to the speed oscillation and the like is avoided, and the starting stability and the reliability of the motor are improved.

It should be noted that the three-stage starting method of the motor includes: the method comprises three stages of positioning, open loop and closed loop, wherein before the open loop is operated, the motor enters a positioning stage to position the initial position of the rotor. Specifically, a direct current is applied to the motor windings so that the rotor is positioned at some initial angle. When the open-loop dragging is performed at the initial angle, the given current of the motor is added to the q-axis (quadrature axis) or the d-axis (direct axis) of the d-q coordinate system, taking the addition to the d-axis as an example, the given current amplitude in the open-loop operation stage is set as Iref, the component Idref1 of the d-axis current amplitude in the first current amplitude is equal to Iref, and the component Iqref1 of the q-axis current amplitude is equal to 0. Taking the q-axis as an example, the given current amplitude in the open-loop operation stage is set as Iref, and the q-axis current amplitude component Iqref1 is Iref and the d-axis current amplitude component Idref1 is 0 in the first current amplitude.

According to the control method of the motor provided by the invention, the following additional technical characteristics can be provided:

in the above technical solution, further setting a second current amplitude of the d-q coordinate system of the motor in the closed-loop operation stage according to the angle deviation and the first current amplitude, includes: taking the product of the cosine value of the angle deviation and the first current amplitude as the d-axis current amplitude in the second current amplitude; and taking the product of the sine value of the angle deviation and the first current amplitude value as the q-axis current amplitude value in the second current amplitude value.

In the technical scheme, the components of the second current amplitude in the closed-loop d-q coordinate system comprise a d-axis current amplitude and a q-axis current amplitude. And the d-axis current amplitude in the second current amplitude is equal to the cosine value of the angle deviation multiplied by the first current amplitude, and the q-axis current amplitude in the second current amplitude is equal to the sine value of the angle deviation multiplied by the first current amplitude, so that the coordinate projection of the given current amplitude in the d-q coordinate system is completed. Therefore, the difference of rotor position estimation adopted in the open-loop operation stage and the closed-loop operation stage is fully considered, when the switching stage starts, the first current amplitude and the first voltage amplitude can be switched to the closed-loop coordinate system d and the closed-loop coordinate system q from the open-loop coordinate system d and the q axis, and then only the reference coordinate system is switched in the switching process, and the amplitude (current upper limit value) and the absolute angle of the given voltage and the given current cannot be suddenly changed, so that the problem that the current magnitude and the phase are suddenly changed due to the inconsistency of the open-loop estimation angle and the closed-loop estimation angle in the open-loop switching and closed-loop switching is effectively solved, the stable switching transition of the open-loop operation stage and the closed-loop operation stage is realized, the problem that the motor cannot stably operate due to the speed oscillation and the like of the motor is avoided, and the starting stability and reliability of the motor are improved.

Specifically, when the open-loop dragging is performed, the given current of the motor is completely added to the q axis or the d axis of the d-q coordinate system, and under the condition that the given current is completely loaded on the d axis, the d axis current amplitude is the amplitude of the given current, the q axis current amplitude is 0, at the moment, the first current amplitude is the d axis current amplitude, the d axis current amplitude in the second current amplitude is the product of the cosine value of the angle deviation and the d axis current amplitude, and the q axis current amplitude in the second current amplitude is the product of the sine value of the angle deviation and the d axis current amplitude. Similarly, under the condition that the given current is completely loaded on the q axis, the q-axis current amplitude is the amplitude of the given current, the d-axis current amplitude is 0, at the moment, the first current amplitude is the q-axis current amplitude, the d-axis current amplitude in the second current amplitude is the product of the cosine value of the angle deviation and the q-axis current amplitude, and the q-axis current amplitude in the second current amplitude is the product of the sine value of the angle deviation and the q-axis current amplitude.

In any of the above technical solutions, further setting a second voltage amplitude of the d-q coordinate system of the motor in the closed-loop operation stage according to the angle deviation and the first voltage amplitude, includes: setting a d-axis voltage amplitude in a second voltage amplitude according to a product of the d-axis voltage amplitude in the first voltage amplitude and a cosine value of the angle deviation and a product of a q-axis voltage amplitude in the first voltage amplitude and a sine value of the angle deviation; and setting the q-axis voltage amplitude in the second voltage amplitude according to the product of the d-axis voltage amplitude in the first voltage amplitude and the sine value of the angle deviation and the product of the q-axis voltage amplitude in the first voltage amplitude and the cosine value of the angle deviation.

In the technical scheme, the components of the second voltage amplitude in the closed-loop d-q coordinate system comprise a d-axis voltage amplitude and a q-axis voltage amplitude. And calculating the product of the d-axis voltage amplitude component in the first voltage amplitude and the cosine value of the angle deviation to obtain a first voltage, and calculating the product of the q-axis voltage amplitude in the first voltage amplitude and the sine value of the angle deviation to obtain a second voltage. And adding the first voltage and the second voltage, and configuring the obtained value as a d-axis voltage amplitude in the second voltage amplitude. And calculating the product of the d-axis voltage amplitude and the sine value of the angle deviation in the first voltage amplitude to obtain a third voltage, and calculating the product of the q-axis voltage amplitude and the cosine value of the angle deviation in the first voltage amplitude to obtain a fourth voltage. And adding the third voltage and the fourth voltage, and configuring the obtained value as a q-axis voltage amplitude in the second voltage amplitude to complete the coordinate projection of the given voltage amplitude in the d-q coordinate system. Therefore, the difference of rotor position estimation adopted in the open-loop operation stage and the closed-loop operation stage is fully considered, when the switching stage begins, the first voltage amplitude and the first voltage amplitude can be switched to the closed-loop coordinate system d and the closed-loop coordinate system q from the open-loop coordinate system d and the q axis, and then only the reference coordinate system is switched in the switching process, and the amplitude (voltage upper limit value) and the absolute angle of the given voltage and the given voltage cannot be suddenly changed, so that the problem that the voltage magnitude and the phase are suddenly changed due to the inconsistency of the open-loop estimation angle and the closed-loop estimation angle in the open-loop switching and closed-loop switching is effectively solved, the stable switching transition of the open-loop operation stage and the closed-loop operation stage is realized, the problem that the motor cannot stably operate due to the speed oscillation and the like of the motor is avoided, and the starting stability and reliability of the motor are improved.

In the above technical solution, further, determining an angular deviation between an open-loop position angle and a closed-loop position angle of the motor includes: determining an open loop position angle according to the rotating speed of the motor; determining a closed loop position angle according to flux linkage information of the motor and a phase-locked loop; the difference between the open-loop position angle and the closed-loop position angle is determined as the angular deviation.

In the technical scheme, the motor is controlled by the input given current due to no control feedback in the open-loop operation stage of the motor, and the motor accelerates the rotor speed of the motor from a certain speed (for example, 0 to 5rad/s) to a preset speed related to the given current at an acceleration. And in the open-loop operation stage, integral operation is carried out on the rotating speed of the rotor, and the open-loop position angle is estimated. And in the closed-loop operation stage, flux linkage information (rotating speed and angle) of the rotor under a d-q coordinate system is determined by using a flux linkage observer, the flux linkage information is used as the input of a phase-locked loop, and the closed-loop position angle of the rotor is estimated through the output of the phase-locked loop. And carrying out subtraction operation on the open-loop position angle and the closed-loop position angle to obtain the angle deviation between the open-loop position angle and the closed-loop position angle.

In any of the above technical solutions, further, the method for controlling a motor further includes: controlling the rotating speed of the motor to be kept within a preset rotating speed range; controlling the current amplitude of the motor to be reduced to an amplitude threshold value; timing a duration for which the current amplitude is less than or equal to the amplitude threshold; and controlling the motor to enter a closed-loop operation stage based on the duration being greater than or equal to the preset duration.

In the technical scheme, after a second current amplitude and a second voltage amplitude under a d-q coordinate system are set, namely, the open-loop coordinate system is switched to a closed-loop coordinate system, the motor is controlled to work at a rotating speed meeting a preset rotating speed range, so that the motor can continuously run at the rotating speed in an open-loop running stage, and therefore smooth running of the motor is ensured.

Under the condition that the duration of the current amplitude which is less than or equal to the amplitude threshold reaches (is more than or equal to) the preset duration, the current amplitude of the d-q coordinate system is configured with the amplitude threshold and is kept for a short time, at the moment, the d-axis current is a positive value, so that the excitation current is increased, the motor magnetizing effect is achieved, the motor is ensured to have larger outlet voltage, the motor is controlled to enter a closed-loop operation stage, and the switching operation of the motor from the open-loop operation to the closed-loop operation is completed. The open-loop and closed-loop switching is further ensured to be rapid and more stable, smooth and reliable, even if the load fluctuates in the switching process, the motor cannot be out of step, and the stability is excellent.

The amplitude threshold value is related to the sampling performance of the motor, and the preset rotating speed range is related to the rotating speed of the motor in the open-loop operation stage.

In any of the above technical solutions, further, controlling the current amplitude of the motor to be reduced to an amplitude threshold includes: and controlling the current amplitude to be reduced for multiple times according to the preset offset.

In the technical scheme, in the process of controlling the current amplitude to decrease, in order to avoid current oscillation caused by direct one-time rapid decrease, the current amplitude is adjusted for multiple times in a step-by-step decreasing mode according to the preset offset, so that the current amplitude can be gradually decreased until the current amplitude is decreased to the amplitude threshold. The motor speed-increasing device is favorable for increasing exciting current, plays a role in increasing the magnetism of the motor, enables the switching process of speed opening and closed-loop control to be controlled stably in the starting process of the motor, ensures that the current of the motor cannot change suddenly, the rotating speed of the motor is stable, the vibration of the motor is greatly weakened, improves the switching success rate, is not influenced by the load characteristic of the motor in the switching process, and has strong universality and wide application range.

In any of the above technical solutions, further, the method for controlling a motor further includes: responding to a starting instruction of the motor, and acquiring a current amplitude of the motor; controlling the motor to enter an open-loop operation stage according to the current amplitude, and acquiring the rotating speed of the motor; and controlling the motor to be switched from the open-loop operation stage to the closed-loop operation stage based on the rotating speed of the motor being greater than or equal to the preset rotating speed.

In the technical scheme, when the motor is started, the motor is controlled to operate in an open loop according to the amplitude (current amplitude) of the given current required by the motor. Specifically, while the motor windings are sequentially conducted according to a predetermined phase sequence by using a specified current amplitude, the commutation frequency is gradually increased to increase the rotation speed of the motor. And in the process of the motor in the open-loop operation stage, the rotating speed of the motor is detected in real time.

Further, if it is detected that the rotation speed of the motor is greater than or equal to the preset rotation speed, which indicates that the motor has accelerated to the required preset rotation speed, and at this time, the motor has already established a sufficiently large back electromotive force, the step of switching the motor from the open-loop operation stage to the closed-loop operation stage may be executed, and the starting process of the motor is completed. Meanwhile, in the process of switching the motor from the open-loop operation stage to the closed-loop operation stage, a second current amplitude and a second voltage amplitude of the motor in the closed-loop operation stage are calculated by utilizing the angular deviation between the open-loop position angle and the closed-loop position angle. The amplitude (current upper limit value) and the absolute angle of the given voltage and the given current cannot be suddenly changed, so that the problem that the current magnitude and the phase are suddenly changed due to the fact that estimated angles of the open loop and the closed loop are inconsistent when the open loop and the closed loop are switched is effectively solved, stable switching transition of an open loop operation stage and a closed loop operation stage is achieved, the problem that the motor cannot stably operate due to the fact that the motor is subjected to speed oscillation and the like is avoided, and the starting stability and the starting reliability of the motor are improved.

According to the second aspect of the present invention, there is also provided a control apparatus of a motor, comprising: the acquisition module is used for acquiring a first current amplitude and a first voltage amplitude of a d-q coordinate system of the motor in an open-loop operation stage in the process of switching the motor from the open-loop operation stage to a closed-loop operation stage; the determining module is used for determining the angle deviation between the open-loop position angle and the closed-loop position angle of the motor; and the switching module is used for setting a second current amplitude and a second voltage amplitude of the d-q coordinate system of the motor in the closed-loop operation stage according to the angle deviation, the first current amplitude and the first voltage amplitude. Therefore, the control device of the motor has all the beneficial effects of the control method of the motor provided by the first aspect, and redundant description is omitted for avoiding repetition.

According to a third aspect of the present invention, there is provided an electric machine comprising: a memory storing a program or instructions; and a processor connected with the memory, wherein the processor implements the steps of the control method of the motor according to the first aspect when executing the program or the instructions. Therefore, the motor has all the beneficial effects of the control method of the motor provided by the first aspect, and redundant description is omitted for avoiding repetition.

According to a fourth aspect of the present invention, a readable storage medium is proposed, on which a program or instructions are stored, which when executed by a processor implement the control method of the electric machine proposed by the first aspect. Therefore, the readable storage medium has all the advantages of the control method of the motor provided by the first aspect, and redundant description is omitted for avoiding repetition.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 shows one of the flow diagrams of a control method of an electric machine according to an embodiment of the invention;

fig. 2 shows a second flow chart of a control method of the motor according to an embodiment of the invention;

fig. 3 shows a third flow chart of a control method of the motor according to an embodiment of the present invention;

fig. 4 shows a fourth flowchart of a control method of the motor according to an embodiment of the present invention;

fig. 5 shows a fifth flowchart of a control method of the motor according to the embodiment of the invention;

fig. 6 shows a sixth flowchart of a control method of the motor according to the embodiment of the invention;

fig. 7 shows a seventh flowchart of a control method of the motor of one embodiment of the present invention;

FIG. 8 illustrates one of the open-loop-closed-loop switching diagrams of a specific embodiment of the present invention;

FIG. 9 illustrates a second open-loop-closed-loop switching diagram according to an embodiment of the present invention;

FIG. 10 is a schematic diagram illustrating the variation of current during the start-up of a motor in accordance with an embodiment of the present invention;

fig. 11 shows a schematic block diagram of a control apparatus of a motor of an embodiment of the present invention;

fig. 12 shows a schematic block diagram of an electric machine according to an embodiment of the invention.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

A control method of a motor, a control apparatus of a motor, and a readable storage medium according to some embodiments of the present invention are described below with reference to fig. 1 to 12.

The first embodiment is as follows:

as shown in fig. 1, according to an embodiment of the first aspect of the present invention, the present invention provides a control method of a motor, including:

102, acquiring a first current amplitude and a first voltage amplitude of a d-q coordinate system of a motor in an open-loop operation stage in the process of switching the motor from the open-loop operation stage to a closed-loop operation stage;

104, determining the angle deviation between the open-loop position angle and the closed-loop position angle of the motor;

and 106, setting a second current amplitude and a second voltage amplitude of the d-q coordinate system of the motor in the closed-loop operation stage according to the angle deviation, the first current amplitude and the first voltage amplitude.

In the embodiment, in the starting process of the motor, the given current is taken as the final target current of the motor to be operated in an open loop mode, and when the motor reaches a certain rotating speed and establishes a certain back electromotive force, the motor needs to be switched to be operated in a closed loop mode, so that the motor can be accurately controlled through control feedback.

Specifically, after the motor meets a certain condition, the motor is switched from an open-loop operation stage to a closed-loop operation stage, and in the process of the open-loop and closed-loop switching stage, a first current amplitude and a first voltage amplitude of an open-loop d-q coordinate system (two-phase rotation coordinate system) during open-loop control of the motor are obtained, namely, the maximum values of a given current and a given voltage of the motor are obtained. Wherein the first current amplitude includes a component of a d-axis (direct axis) current amplitude and a component of a q-axis (quadrature axis) current amplitude in the open loop, and likewise, the first voltage amplitude includes a component of a d-axis (direct axis) voltage amplitude and a q-axis (quadrature axis) voltage amplitude in the open loop. Estimating a rotor position angle (open-loop position angle) of the motor during open-loop operation of the motor and a rotor position angle (closed-loop position angle) of the motor during closed-loop operation of the motor, determining a second current amplitude value of the motor in a closed-loop operation stage by using an angle deviation between the rotor position angles corresponding to the open-loop and the closed-loop and a first current amplitude value, and determining a second voltage amplitude value of the motor in the closed-loop operation stage by using the angle deviation between the open-loop position angle and the closed-loop position angle and the first voltage amplitude value. Therefore, the difference of rotor position estimation adopted in the open-loop and closed-loop operation stages is fully considered, and when the switching stage begins, the first current amplitude and the first voltage amplitude can be switched to the d axis and the q axis of the closed-loop d-q coordinate system from the d axis and the q axis of the open-loop d-q coordinate system, namely, the given current and the given voltage under the open-loop d-q coordinate system are projected onto the closed-loop d-q coordinate system according to the angle deviation.

According to the motor control method provided by the invention, the second current amplitude and the second voltage amplitude of the closed-loop d-q coordinate system are obtained by converting the first current amplitude and the first voltage amplitude in proportion, only the reference coordinate system (the d-q coordinate system of the given current and the given voltage) is switched in the switching stage process, namely coordinate projection, and the amplitude (the current upper limit value) and the absolute angle of the given voltage and the given current cannot be suddenly changed, so that the problem that the current magnitude and the phase are suddenly changed in switching due to the inconsistency of the open-loop estimation angle and the closed-loop estimation angle in the open-loop switching and closed-loop switching is effectively solved, the stable switching transition between the open-loop operation stage and the closed-loop operation stage is realized, the problem that the motor cannot stably operate due to the speed oscillation and the like is avoided, and the starting stability and reliability of the motor are improved.

Example two:

as shown in fig. 2, according to an embodiment of the present invention, there is provided a control method of a motor, including:

step 202, acquiring a first current amplitude and a first voltage amplitude of a d-q coordinate system when the motor operates in an open loop mode in a switching stage of the motor;

step 204, estimating an open loop position angle through the rotating speed of the motor;

step 206, estimating a closed loop position angle through a motor flux linkage and a motor phase-locked loop;

208, performing subtraction operation on the open-loop position angle and the closed-loop position angle to determine an angle deviation;

and step 210, setting a second current amplitude and a second voltage amplitude of the d-q coordinate system when the motor is in the closed operation according to the angle deviation, the first current amplitude and the first voltage amplitude.

In this embodiment, since the motor is operated without control feedback during the open loop operation phase, control is performed by inputting a given current, at which time the motor accelerates the rotational speed of the rotor of the motor from a certain rotational speed (e.g., 0, -5rad/s) to a preset rotational speed associated with the given current with an acceleration. And in the open-loop operation stage, integral operation is carried out on the rotating speed of the rotor, and the open-loop position angle is estimated. And in the closed-loop operation stage, determining the flux linkage information of the rotor under the d-q coordinate system by using a flux linkage observer, taking the flux linkage information as the input of a phase-locked loop, and estimating the closed-loop position angle of the rotor through the output of the phase-locked loop. And carrying out subtraction operation on the open-loop position angle and the closed-loop position angle to obtain the angle deviation between the rotor position angles corresponding to the open loop and the closed loop.

Specifically, as shown in fig. 8 and 9, the estimated open-loop position angle is θ 1, the estimated closed-loop position angle is θ 2, and the angular deviation Δ θ between the open-loop position and the closed-loop position is θ 1 — θ 2.

Example three:

as shown in fig. 3, according to an embodiment of the present invention, there is provided a control method of a motor, including:

step 302, in the switching stage of the motor, acquiring an open-loop current amplitude and an open-loop voltage amplitude of a d-q coordinate system when the motor operates in an open loop;

step 304, calculating an angle deviation between the rotor position angle during the open-loop operation of the motor and the rotor position angle during the closed-loop operation of the motor;

step 306, multiplying the cosine value of the angle deviation and the current component of the d axis in the open-loop current amplitude to be used as the current component of the d axis in the closed-loop current amplitude;

step 308, multiplying the sine value of the angle deviation and the current component of the d axis in the open-loop current amplitude to obtain a current component of the q axis in the closed-loop current amplitude;

step 310, setting a voltage component of a d axis in a closed-loop voltage amplitude according to a product of a voltage component of a d axis in the open-loop current amplitude and a cosine value of the angle deviation and according to a product of a voltage component of a q axis in the open-loop current amplitude and a sine value of the angle deviation;

step 312, a q-axis voltage component in the closed-loop voltage amplitude is set according to a product of a d-axis voltage component in the open-loop voltage amplitude and a sine value of the angle deviation and a product of a q-axis voltage component in the open-loop voltage amplitude and a cosine value of the angle deviation.

In this embodiment, the components of the closed-loop current magnitude (second current magnitude) in the d-q coordinate system include a d-axis current magnitude and a q-axis current magnitude.

When the open-loop dragging is carried out, and the given current is loaded on the d axis, the current component (d axis current amplitude) of the d axis in the closed-loop current amplitude (second current amplitude) is equal to the cosine value of the angle deviation multiplied by the current component of the d axis in the open-loop current amplitude (first current amplitude), and the current component (q axis current amplitude) of the q axis in the closed-loop current amplitude is equal to the sine value of the angle deviation multiplied by the current component of the d axis in the open-loop current amplitude, so that the coordinate projection of the given current amplitude in the d-q coordinate system is completed. Therefore, the difference of rotor position estimation adopted in the open-loop operation stage and the closed-loop operation stage is fully considered, when the switching stage begins, the open-loop current amplitude and the open-loop voltage amplitude can be switched to the closed-loop coordinate system d and q axes from the open-loop coordinate system d and q axes, and then only the reference coordinate system is switched in the switching process, and the amplitude (current upper limit value) and the absolute angle of the given voltage and the given current cannot be suddenly changed, so that the problem that the current magnitude and the phase are suddenly changed due to the inconsistency of the open-loop estimation angle and the closed-loop estimation angle in the open-loop switching and closed-loop switching process is effectively solved, the stable switching transition of the open-loop operation stage and the closed-loop operation stage is realized, the problem that the motor cannot stably operate due to the speed oscillation and the like of the motor is avoided, and the starting stability and reliability of the motor are improved.

Specifically, as shown in fig. 8, the given current of the motor is added to the d-axis, and the component of the d-axis in the closed-loop current amplitude is calculated by using the following formula (1). The q-axis component of the closed-loop current amplitude is calculated using the following equation (2).

Idref2＝Idref1×cosΔθ； (1)

Iqref2＝Idref1×sinΔθ； (2)

Wherein Idref2 is the d-axis current component in the closed-loop current amplitude, Iqref2 is the q-axis current component in the closed-loop current amplitude, and Δ θ is the angular deviation.

The same principle is that the given current of the motor is added to the q axis, and the closed loop current amplitude is calculated by adopting the following formulas (3) and (4):

Idref2＝Iqref1×cosΔθ； (3)

Iqref2＝Iqref1×sinΔθ； (4)

it should be noted that, since the given current of the motor is added to the q-axis (quadrature axis) or the d-axis (direct axis) of the d-q coordinate system during the open loop operation, Iqref1 or Idref1 is the magnitude (Iref) of the given current. Further, the components of the closed-loop voltage magnitude in the closed-loop d-q coordinate system include a d-axis voltage magnitude and a q-axis voltage magnitude.

And multiplying the cosine value of the angle deviation and the voltage component of the d axis in the open-loop voltage amplitude to obtain a first voltage through calculation. And performing multiplication operation on the sine value of the angle deviation and the voltage component of the q axis in the open-loop voltage amplitude, and calculating to obtain a second voltage. And adding the first voltage and the second voltage, and configuring the obtained voltage value as a voltage component of a d axis under a d-q coordinate system in the closed-loop voltage amplitude.

Similarly, the sine value of the angle deviation and the voltage component of the d axis in the open-loop voltage amplitude are multiplied, and a third voltage is obtained through calculation. And performing multiplication operation on the cosine value of the angle deviation and the voltage component of the q axis in the open-loop voltage amplitude, and calculating to obtain a fourth voltage. And adding the third voltage and the fourth voltage, and configuring the obtained voltage value as a q-axis voltage component in the closed-loop voltage amplitude to complete the coordinate projection of the given voltage amplitude in a d-q coordinate system. Thereby fully accounting for the differences in rotor position estimates employed during the open-loop and closed-loop operating phases, at the start of the switching phase, the open-loop voltage amplitude and the open-loop voltage amplitude can be switched from the d axis and the q axis of the open-loop coordinate system to the d axis and the q axis of the closed-loop coordinate system, furthermore, in the switching process, only the reference coordinate system is switched, and the given voltage and the amplitude (voltage upper limit value) and absolute angle of the given voltage do not change suddenly, thereby effectively solving the problem that the voltage and the phase are suddenly changed when switching due to the inconsistent estimation angles of the open loop and the closed loop when switching the open loop and the closed loop, realizing the stable switching transition of the open loop operation stage and the closed loop operation stage, avoiding the problem that the motor cannot stably operate due to the speed oscillation and the like, the closed-loop control can be reliably accessed in the starting process of the motor, and the starting stability and reliability of the motor are improved.

Specifically, as shown in fig. 9, the d-axis voltage component of the d-q coordinate system in the closed-loop voltage amplitude is calculated specifically using the following equation (5). The q-axis voltage component of the d-q coordinate system in the closed-loop voltage amplitude is calculated specifically using the following equation (6).

Vdref2＝Vdref1×cosΔθ-Vqref1×sinΔθ； (5)

Vqref2＝Vdref1×sinΔθ+Vqref1×cosΔθ； (6)

Where Vdref2 is the voltage component of the d-axis in the closed-loop voltage amplitude, Vqref2 is the voltage component of the q-axis in the closed-loop voltage amplitude, Δ θ is the angular deviation, Vdref1 is the voltage component of the d-axis in the open-loop voltage amplitude, and Vqref1 is the voltage component of the q-axis in the open-loop voltage amplitude.

Example four:

as shown in fig. 4, according to an embodiment of the present invention, there is provided a control method of a motor, including:

step 402, acquiring an open-loop current amplitude and an open-loop voltage amplitude of a d-q coordinate system during open-loop operation of the motor at a switching stage of converting the open-loop operation of the motor into closed-loop operation;

step 404, calculating an angle deviation between a rotor position angle when the motor operates in an open loop mode and a rotor position angle when the motor operates in a closed loop mode;

step 406, setting a closed-loop current amplitude and a closed-loop voltage amplitude of a d-q coordinate system of the motor in a closed-loop operation stage according to the angle deviation, the open-loop current amplitude and the open-loop voltage amplitude;

step 408, controlling the motor to operate at a rotating speed meeting a preset rotating speed range;

step 410, adjusting the current amplitude of the motor to be less than or equal to an amplitude threshold value;

step 412, judging whether the duration of the current amplitude value smaller than or equal to the amplitude threshold value reaches a preset duration, if so, entering step 414, and if not, entering step 410;

and step 414, controlling the motor to operate in a closed loop.

In this embodiment, after the closed-loop current amplitude (second current amplitude) and the closed-loop voltage amplitude (second voltage amplitude) in the d-q coordinate system are set by using the angle deviation, the open-loop current amplitude (first current amplitude) and the open-loop voltage amplitude (first voltage amplitude), that is, after the closed-loop coordinate system is switched to the closed-loop coordinate system from the open-loop coordinate system, the motor is controlled to operate at a rotation speed satisfying a preset rotation speed range, so that the motor can continue to operate at the rotation speed in the open-loop operation stage, thereby ensuring smooth operation of the motor. At this point, the current amplitude of the motor is adjusted, i.e. the maximum value of the given current is set, so that the current amplitude starts to decrease until the current amplitude decreases to the specified amplitude threshold. When the duration time of the current amplitude which is less than or equal to the amplitude threshold reaches (is more than or equal to) the preset duration time, the current amplitude of the d-q coordinate system is configured with the amplitude threshold and is kept for a short time, at the moment, the d-axis current is a positive value, the excitation current is increased, the motor magnetizing effect is achieved, the motor is ensured to have larger outlet voltage, the motor is controlled to enter a closed-loop operation stage, and the switching operation of the motor from the open-loop operation to the closed-loop operation is completed. The open-loop and closed-loop switching is further ensured to be rapid and more stable, smooth and reliable, even if the load fluctuates in the switching process, the motor cannot be out of step, and the stability is excellent.

The amplitude threshold is related to a sampling structure of the motor, and the preset rotation speed range is related to the rotation speed of the motor in the open-loop operation stage, for example, the upper limit value of the preset rotation speed range is the sum of the rotation speed of the motor in the open-loop operation stage and the error amount, and the lower limit value of the preset rotation speed range is the difference between the rotation speed of the motor in the open-loop operation stage and the error amount.

Further, after the motor enters a closed-loop operation stage, the feedback signal of the motor is periodically acquired according to a preset time interval, so that the current and/or the rotating speed of the motor are detected, the current and/or the rotating speed of the motor are adjusted through closed-loop control, and then the detected current and/or the detected rotating speed of the motor are input into a closed-loop control system as the feedback signal to adjust the current and/or the rotating speed of the motor, so that the motor can reach the required current and/or rotating speed. The preset time interval can be reasonably set according to the response time of closed-loop control.

Example five:

as shown in fig. 5, according to an embodiment of the present invention, there is provided a control method of a motor, including:

step 502, acquiring an open-loop current amplitude and an open-loop voltage amplitude of a d-q coordinate system during open-loop operation of the motor at a switching stage of converting the open-loop operation of the motor into closed-loop operation;

step 504, calculating an angle deviation between the rotor position angle when the motor operates in an open loop mode and the rotor position angle when the motor operates in a closed loop mode;

step 506, setting a closed-loop current amplitude and a closed-loop voltage amplitude of a d-q coordinate system when the motor operates in a closed loop according to the angle deviation, the open-loop current amplitude and the open-loop voltage amplitude;

step 508, controlling the motor to operate at a rotating speed meeting a preset rotating speed range;

step 510, gradually reducing the current amplitude of the motor according to a preset offset;

step 512, judging whether the duration of the current amplitude which is less than or equal to the amplitude threshold reaches a preset duration, if so, entering step 514, and if not, entering step 510;

and step 514, controlling the motor to operate in a closed loop.

In the embodiment, in the process of controlling the current amplitude to decrease, in order to avoid current oscillation caused by direct one-time rapid decrease, the current amplitude is adjusted for multiple times in a step-by-step decreasing manner according to a preset offset, so that the current amplitude can be gradually and linearly decreased until the current amplitude is decreased to be less than or equal to an amplitude threshold. The motor speed-increasing device is favorable for increasing exciting current, plays a role in increasing the magnetism of the motor, enables the switching process of speed opening and closed-loop control to be controlled stably in the starting process of the motor, ensures that the current of the motor cannot change suddenly, the rotating speed of the motor is stable, the vibration of the motor is greatly weakened, improves the switching success rate, is not influenced by the load characteristic of the motor in the switching process, and has strong universality and wide application range.

Specifically, for example, after the motor is switched from the open-loop coordinate system to the closed-loop coordinate system, the current amplitude is still the amplitude Iref of the specified current In the open-loop operation stage, the preset offset is In, and the current amplitude Iref1 after the first decrease is equal to Iref-In; after a specified interval, controlling the current amplitude to decrease for the second time, wherein the current amplitude Iref2 after the second decrease is equal to Iref 1-In; and so on until the current amplitude drops from Iref to Idmin (amplitude threshold).

It can be understood that, in the current amplitude decreasing stage, in order to reduce the motor jitter as much as possible, it is necessary to not only keep the motor rotation speed constant, but also control the phase of a given current to keep constant.

Example six:

as shown in fig. 6, according to an embodiment of the present invention, there is provided a control method of a motor, including:

step 602, acquiring a current amplitude of a motor under the condition of receiving a starting instruction of the motor;

step 604, operating the motor according to the current amplitude open loop;

step 606, judging whether the rotating speed of the motor exceeds a preset rotating speed, if so, entering step 608, and if not, entering step 604;

step 608, controlling the motor to enter a switching stage;

step 610, setting a closed-loop current amplitude and a closed-loop voltage amplitude of a d-q coordinate system when the motor operates in a closed-loop mode according to the angle deviation between the opening and closing of the motor and the closed-loop, and the open-loop current amplitude and the open-loop voltage amplitude of the d-q coordinate system when the motor operates in the open-loop mode;

step 612, maintaining the rotating speed of the motor within a preset rotating speed range;

step 614, adjusting the current amplitude of the motor to be less than or equal to an amplitude threshold value;

step 616, judging whether the duration of the current amplitude smaller than or equal to the amplitude threshold reaches a preset duration, if so, entering step 618, and if not, entering step 614;

and step 618, controlling the motor to operate in a closed loop.

Further, if it is detected that the rotation speed of the motor exceeds (is greater than or equal to) the preset rotation speed of the motor start, it indicates that the motor has accelerated to the required target rotation speed, and at this time, the motor has established a sufficient back electromotive force, the motor can be controlled to enter an open-loop and closed-loop switching stage, and then the step of converting the motor from open-loop operation to closed-loop operation is performed, so as to achieve the purpose of completing the motor start. Meanwhile, in the process that the motor is in the switching stage, the closed-loop current amplitude (second current amplitude) and the closed-loop voltage amplitude (second voltage amplitude) of the motor in the closed-loop operation stage are converted by using the estimated angle deviation of the rotor position angle in the open-loop operation and the closed-loop operation. Therefore, when the open-loop d-q coordinate system is switched to the closed-loop d-q coordinate system, the amplitude (reference current upper limit value) and the absolute angle of the given voltage and the given current in the coordinate system cannot be suddenly changed, the problem that the current magnitude and the phase are suddenly changed when switching is caused by the fact that the estimation angles of the open loop and the closed loop are inconsistent during switching is effectively solved, stable switching transition of an open-loop operation stage and a closed-loop operation stage is achieved, the problem that the motor cannot stably operate due to speed oscillation and the like of the motor is avoided, and starting stability and reliability of the motor are improved.

It can be understood that the rotation speed of the motor can be detected by a rotation speed detection device, and can also be obtained by converting the current and the voltage of a d-q coordinate system when the motor operates in an open loop mode.

It should be noted that, in response to a start command of the motor, before the open loop operation, the motor is controlled to enter a positioning stage to determine an initial position angle of the rotor of the motor. And positioning the rotor at the initial position angle, and controlling the motor to operate in an open-loop mode according to the amplitude of the given current, wherein the motor enters an open-loop operation stage.

It is worth mentioning that whether to execute the switching from the open-loop operation to the closed-loop operation of the motor can be judged by the rotating speed of the motor, and the time of the open-loop operation and the rotating speed of the motor have a certain corresponding relation due to the gradual rise of the motor in the open-loop operation stage. Therefore, whether to execute the switching from the open-loop operation to the closed-loop operation of the motor can be controlled by the time of the open-loop operation. Specifically, the motor is converted from the open-loop operation phase to the closed-loop operation phase based on the operating time period for which the motor is in open-loop operation exceeding (being greater than or equal to) the time period threshold.

Example seven:

as shown in fig. 7, according to an embodiment of the present invention, there is provided a control method of a motor, including:

step 702, responding to a starting instruction of a motor;

step 704, the motor enters a positioning stage;

step 706, operating the motor in an open loop;

step 708, ending the open-loop time, and starting to switch the coordinate system to project the given current and the given voltage to the closed-loop coordinate system;

step 710, keeping the rotating speed unchanged, gradually reducing the given current amplitude to an amplitude threshold value Idmin, and keeping the preset duration;

and 712, determining that the closed-loop switching is completed and the motor operates in a closed loop.

In this embodiment, as shown in fig. 10, the motor enters the Positioning (PARK) phase first and enters the open loop operation phase. Due to the open-loop dragging, the given current of the motor is added to the d-axis or the q-axis, and the given current amplitude in the open-loop phase is set to Iref (Idref1 is Iref, Iqref1 is 0), for example. When the open loop is accelerated to the starting speed, the switching stage is started, and the given current component and the given voltage component are simultaneously switched to the d-q axes of the closed loop d-q coordinate system from the d-q axes of the open loop d-q coordinate system at the beginning of the switching stage, namely the given current and the given voltage in the open loop coordinate system are projected on the closed loop coordinate system.

Specifically, as shown in fig. 8, at the time of starting switching, assuming that the open-loop position angle is θ 1 (the open-loop angle is integrated at a predetermined rotation speed), the closed-loop position angle is θ 2 (the closed-loop angle is obtained by flux linkage observation and phase-locked loop), the angular deviation between the open loop and the closed loop is Δ θ 1 — θ 2, and the predetermined currents in the open-loop coordinate systems d1 and q1 are projected onto the closed-loop coordinate systems d2 and q 2. Wherein, the given current projection Idref2 on the d-axis is Iref × cos Δ θ; given the current projection Iqref2 on the q-axis, Iref × sin Δ θ.

Similarly, as shown in fig. 9, given voltages in the open-loop coordinate systems d1, q1 are projected onto the closed-loop coordinate systems d2, q 2. The given current projection Vdref2 on the d-axis is Vdref1 × cos Δ θ -Vqref1 × sin Δ θ; the given current projection Vqref2 on the q-axis is Vdref1 × sin Δ θ + Vqref1 × cos Δ θ.

Therefore, when the loop is switched in an open loop mode, only the reference coordinate system, namely the coordinate projection is switched, the amplitude and the absolute angle of the given voltage and the given current cannot be suddenly changed, and therefore smooth transition in switching is guaranteed.

Further, as shown in fig. 10, the switching phase is entered, and after the coordinate system is switched, the motor speed is kept unchanged, the phase of the given current Iref is also kept unchanged, the amplitude of the given current is linearly decreased, and finally decreased to be equal to the amplitude threshold Idmin, and when the given current is decreased to the amplitude threshold Idmin and kept for a given time, the closed-loop switching is completed. Therefore, the stable switching transition of the open loop and the closed loop is realized, and the starting stability and reliability of the motor are improved.

Example eight:

as shown in fig. 11, according to an embodiment of the second aspect of the present invention, there is provided a control apparatus 800 of a motor, including: an acquisition module 802, a determination module 804, and a switching module 806.

In detail, the obtaining module 802 is configured to obtain a first current amplitude and a first voltage amplitude of a d-q coordinate system of the motor in the open-loop operation stage during the process of switching the motor from the open-loop operation stage to the closed-loop operation stage. A determination module 804, the determination module 804 configured to determine an angular deviation between an open-loop position angle and a closed-loop position angle of the motor. The switching module 806 is configured to set a second current amplitude and a second voltage amplitude of the d-q coordinate system of the motor in the closed-loop operation stage according to the angle deviation, the first current amplitude, and the first voltage amplitude.

In the embodiment, after the motor meets a certain condition, the motor is switched from the open-loop operation stage to the closed-loop operation stage, and during the switching stage between the open loop and the closed loop, a first current amplitude and a first voltage amplitude of an open-loop d-q coordinate system (two-phase rotation coordinate system) during the open-loop control of the motor are obtained, namely, the maximum values of the given current and the given voltage of the motor are obtained. Wherein the first current amplitude includes a component of a d-axis (direct axis) current amplitude and a component of a q-axis (quadrature axis) current amplitude in the open loop, and likewise, the first voltage amplitude includes a component of a d-axis (direct axis) voltage amplitude and a q-axis (quadrature axis) voltage amplitude in the open loop. Estimating a rotor position angle (open-loop position angle) of the motor during open-loop operation of the motor and a rotor position angle (closed-loop position angle) of the motor during closed-loop operation of the motor, determining a second current amplitude value of the motor in a closed-loop operation stage by using an angle deviation between the rotor position angles corresponding to the open-loop and the closed-loop and a first current amplitude value, and determining a second voltage amplitude value of the motor in the closed-loop operation stage by using the angle deviation between the open-loop position angle and the closed-loop position angle and the first voltage amplitude value. Therefore, the difference of rotor position estimation adopted in the open-loop and closed-loop operation stages is fully considered, and when the switching stage begins, the first current amplitude and the first voltage amplitude can be switched to the d axis and the q axis of the closed-loop d-q coordinate system from the d axis and the q axis of the open-loop d-q coordinate system, namely, the given current and the given voltage under the open-loop d-q coordinate system are projected onto the closed-loop d-q coordinate system according to the angle deviation. Therefore, in the process of the switching stage, only the reference coordinate system (the d-q coordinate system of the given current and the given voltage) is switched, namely the coordinate projection, the amplitude (the current upper limit value) and the absolute angle of the given voltage and the given current cannot be suddenly changed, the problem that the current magnitude and the phase are suddenly changed when the switching is carried out due to the fact that the estimation angles of the open loop and the closed loop are inconsistent when the open loop and the closed loop are switched is effectively solved, the stable switching transition of the open loop running stage and the closed loop running stage is realized, the problem that the motor cannot stably run due to the fact that the motor has speed oscillation and the like is avoided, and the starting stability and the starting reliability of the motor are improved.

Further, the switching module 806 is further configured to use a product of the cosine value of the angle deviation and the first current amplitude as the d-axis current amplitude in the second current amplitude. The switching module 806 is further configured to use a product of a sine of the angular deviation and the first current amplitude as the q-axis current amplitude in the second current amplitude.

In this embodiment, the components of the second current magnitude (closed-loop current magnitude) in the closed-loop d-q coordinate system include a d-axis current magnitude and a q-axis current magnitude. And the current component of the d axis (the current amplitude of the d axis) in the second current amplitude is equal to the cosine value of the angle deviation multiplied by the first current amplitude (the open-loop current amplitude), and the current component of the q axis (the current amplitude of the q axis) in the second current amplitude is equal to the sine value of the angle deviation multiplied by the first current amplitude, so that the coordinate projection of the given current amplitude under a d-q coordinate system is completed. Therefore, the difference of rotor position estimation adopted in the open-loop operation stage and the closed-loop operation stage is fully considered, when the switching stage starts, the first current amplitude and the first voltage amplitude can be switched to the closed-loop coordinate system d and the closed-loop coordinate system q from the open-loop coordinate system d and the q axis, and then only the reference coordinate system is switched in the switching process, and the amplitude (current upper limit value) and the absolute angle of the given voltage and the given current cannot be suddenly changed, so that the problem that the current magnitude and the phase are suddenly changed due to the inconsistency of the open-loop estimation angle and the closed-loop estimation angle in the open-loop switching and closed-loop switching is effectively solved, the stable switching transition of the open-loop operation stage and the closed-loop operation stage is realized, the problem that the motor cannot stably operate due to the speed oscillation and the like of the motor is avoided, and the starting stability and reliability of the motor are improved.

Further, the switching module 806 is further configured to set the d-axis voltage amplitude in the second voltage amplitude according to a product of the d-axis voltage amplitude in the first voltage amplitude and a cosine value of the angle deviation, and a product of the q-axis voltage amplitude in the first voltage amplitude and a sine value of the angle deviation. The switching module 806 is further configured to set a q-axis voltage amplitude of the second voltage amplitude according to a product of the d-axis voltage amplitude of the first voltage amplitude and a sine value of the angular deviation and a product of a q-axis voltage amplitude of the first voltage amplitude and a cosine value of the angular deviation.

In this embodiment, the components of the second voltage magnitude (closed-loop voltage magnitude) in the closed-loop d-q coordinate system include a d-axis voltage magnitude and a q-axis voltage magnitude. The cosine value of the angle deviation and the d-axis voltage amplitude in the first voltage amplitude are multiplied to obtain a first voltage through calculation, and the sine value of the angle deviation and the q-axis voltage amplitude in the first voltage amplitude (open-loop voltage amplitude) are multiplied to obtain a second voltage through calculation. And adding the first voltage and the second voltage, and configuring the obtained value as a voltage component of a d-axis of a d-q coordinate system in the second voltage amplitude. Similarly, a sine value of the angle deviation and a d-axis voltage amplitude value in the first voltage amplitude value are multiplied to calculate a third voltage, and a cosine value of the angle deviation and a q-axis voltage amplitude value in the first voltage amplitude value are multiplied to calculate a fourth voltage. And adding the third voltage and the fourth voltage, and configuring the obtained value as a q-axis voltage amplitude in the second voltage amplitude to complete the coordinate projection of the given voltage amplitude in the d-q coordinate system. Thereby fully accounting for the differences in rotor position estimates employed during the open-loop and closed-loop operating phases, at the start of the switching phase, the first voltage amplitude and the first voltage amplitude can be switched from the d and q axes of the open-loop coordinate system to the d and q axes of the closed-loop coordinate system, furthermore, in the switching process, only the reference coordinate system is switched, and the given voltage and the amplitude (voltage upper limit value) and absolute angle of the given voltage do not change suddenly, thereby effectively solving the problem that the voltage and the phase are suddenly changed when switching due to the inconsistent estimation angles of the open loop and the closed loop when switching the open loop and the closed loop, realizing the stable switching transition of the open loop operation stage and the closed loop operation stage, avoiding the problem that the motor cannot stably operate due to the speed oscillation and the like, the closed-loop control can be reliably accessed in the starting process of the motor, and the starting stability and reliability of the motor are improved.

Further, the determining module 804 is further configured to determine the open-loop position angle according to a rotation speed of the motor. The determining module 804 is further configured to determine a closed-loop position angle according to flux linkage information of the motor and the phase-locked loop. The determining module 804 is further configured to determine a difference between the open-loop position angle and the closed-loop position angle as the angle deviation.

In this embodiment, since the motor has no control feedback in the open-loop operation stage, the control is performed by the input given current, and the motor accelerates the rotor speed of the motor from a certain speed to a preset speed related to the given current with an acceleration. And in the open-loop operation stage, integral operation is carried out on the rotating speed of the rotor, and the open-loop position angle is estimated. And in the closed-loop operation stage, determining the flux linkage information of the rotor under the d-q coordinate system by using a flux linkage observer, taking the flux linkage information as the input of a phase-locked loop, and estimating the closed-loop position angle of the rotor through the output of the phase-locked loop. And carrying out subtraction operation on the open-loop position angle and the closed-loop position angle to obtain the angle deviation between the rotor position angles corresponding to the open loop and the closed loop.

Further, the control apparatus 800 for the motor further includes: a control module (not shown in the figure) for controlling the rotation speed of the motor to be kept within a preset rotation speed range; and controlling the current amplitude of the motor to be reduced to an amplitude threshold value. And a timing module (not shown) for timing the duration of the current amplitude less than or equal to the amplitude threshold. The control module is also used for controlling the motor to enter a closed-loop operation stage based on the duration being greater than or equal to the preset duration.

In this embodiment, after the second current amplitude and the second voltage amplitude in the d-q coordinate system are set, that is, after the open-loop coordinate system is switched to the closed-loop coordinate system, the motor is controlled to operate at a rotation speed satisfying the preset rotation speed range, so that the motor can continue to operate at the rotation speed in the open-loop operation stage, thereby ensuring smooth operation of the motor, and at this time, the current amplitude of the motor starts to be adjusted, that is, the maximum value of the given current is set, so that the current amplitude starts to be reduced until the current amplitude is reduced to the specified amplitude threshold. Under the condition that the duration of the current amplitude which is less than or equal to the amplitude threshold reaches (is more than or equal to) the preset duration, the current amplitude of the d-q coordinate system is configured with the amplitude threshold and is kept for a short time, at the moment, the d-axis current is a positive value, so that the excitation current is increased, the motor magnetizing effect is achieved, the motor is ensured to have larger outlet voltage, the motor is controlled to enter a closed-loop operation stage, and the switching operation of the motor from the open-loop operation to the closed-loop operation is completed. The open-loop and closed-loop switching is further ensured to be rapid and more stable, smooth and reliable, even if the load fluctuates in the switching process, the motor cannot be out of step, and the stability is excellent.

Further, the control module is further configured to control the current amplitude to decrease for multiple times according to a preset offset.

In the embodiment, in the process of controlling the current amplitude to decrease, in order to avoid current oscillation caused by direct one-time rapid decrease, the current amplitude is adjusted for multiple times in a step-by-step decreasing manner according to a preset offset, so that the current amplitude can be gradually decreased until the current amplitude is decreased to an amplitude threshold. The motor speed-increasing device is favorable for increasing exciting current, plays a role in increasing the magnetism of the motor, enables the switching process of speed opening and closed-loop control to be controlled stably in the starting process of the motor, ensures that the current of the motor cannot change suddenly, the rotating speed of the motor is stable, the vibration of the motor is greatly weakened, improves the switching success rate, is not influenced by the load characteristic of the motor in the switching process, and has strong universality and wide application range.

Further, the obtaining module 802 is further configured to obtain a current amplitude of the motor in response to a starting instruction of the motor; the control device 800 of the motor further includes: a starting module (not shown in the figure), which is used for controlling the motor to enter an open-loop operation stage according to the current amplitude; the obtaining module 802 is further configured to obtain a rotation speed of the motor; the switching module 806 is further configured to control the motor to switch from the open-loop operation stage to the closed-loop operation stage based on the rotation speed of the motor being greater than or equal to the preset rotation speed.

In this embodiment, the motor executes the start-up routine upon receiving a start-up instruction of the motor. At the moment, the motor is controlled to run in an open-loop mode, and the current conversion frequency is gradually increased while the motor winding is sequentially conducted according to the preset phase sequence by using the specified current amplitude, so that the rotating speed of the motor is increased. And when the motor operates in an open loop, the rotating speed of the motor is detected in real time. If the detected rotating speed of the motor exceeds (is more than or equal to) the preset rotating speed of the motor starting, the motor is accelerated to the required target rotating speed, and at the moment, the motor has established enough counter electromotive force, the motor can be controlled to enter an open-loop and closed-loop switching stage, so that the step of converting the open-loop operation of the motor into the closed-loop operation is carried out, and the purpose of finishing the starting of the motor is achieved. Meanwhile, in the process that the motor is in the switching stage, the closed-loop current amplitude (second current amplitude) and the closed-loop voltage amplitude (second voltage amplitude) of the motor in the closed-loop operation stage are converted by using the estimated angle deviation of the rotor position angle in the open-loop operation and the closed-loop operation. Therefore, when the open-loop d-q coordinate system is switched to the closed-loop d-q coordinate system, the amplitude (reference current upper limit value) and the absolute angle of the given voltage and the given current in the coordinate system cannot be suddenly changed, the problem that the current magnitude and the phase are suddenly changed when switching is caused by the fact that the estimation angles of the open loop and the closed loop are inconsistent during switching is effectively solved, stable switching transition of an open-loop operation stage and a closed-loop operation stage is achieved, the problem that the motor cannot stably operate due to speed oscillation and the like of the motor is avoided, and starting stability and reliability of the motor are improved.

Example nine:

as shown in fig. 12, according to an embodiment of the third aspect of the present invention, it is proposed that the electric machine 900 comprises a memory 902 and a processor 904. The memory 902 stores programs or instructions, among other things. The processor 904 is coupled to the memory 902. The steps of the method for controlling an electric motor according to the embodiment of the first aspect are implemented when the processor 904 executes a program or instructions. Therefore, the motor has all the beneficial effects of the control method of the motor provided by the embodiment of the first aspect, and redundant description is omitted for avoiding repetition.

Specifically, the electric machine includes a Permanent Magnet Synchronous Machine (PMSM) that employs a sensorless control strategy at start-up.

Example ten:

according to an embodiment of a fourth aspect of the present invention, a readable storage medium is proposed. The readable storage medium stores a program or instructions, and the program or instructions when executed by the processor implement the control method of the motor provided in the embodiment of the first aspect. Therefore, the readable storage medium has all the advantages of the control method for the motor provided in the embodiment of the first aspect, and redundant description is omitted for avoiding redundancy.

In the present invention, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. Further, it should be noted that the scope of the methods and apparatus of the embodiments of the present application is not limited to performing the functions in the order illustrated or discussed, but may include performing the functions in a substantially simultaneous manner or in a reverse order based on the functions involved, e.g., the methods described may be performed in an order different than that described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

In the description herein, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solutions of the present application may be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal (such as a mobile phone, a computer, a server, or a network device) to execute the method according to the embodiments of the present application.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

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