CN117792161A

CN117792161A - Control method and device of permanent magnet synchronous motor, electronic equipment and storage medium

Info

Publication number: CN117792161A
Application number: CN202311681530.2A
Authority: CN
Inventors: 李卫伟
Original assignee: Yijing Microelectronics Taizhou Co ltd
Current assignee: Yijing Microelectronics Taizhou Co ltd
Priority date: 2023-12-08
Filing date: 2023-12-08
Publication date: 2024-03-29

Abstract

The embodiment of the application provides a control method and device of a permanent magnet synchronous motor, electronic equipment and a storage medium. The method comprises the following steps: starting the permanent magnet synchronous motor according to initial parameters, wherein the initial parameters comprise a forced position and an initial Q-axis current; when the permanent magnet synchronous motor is in a starting state, calculating a first estimated position of the permanent magnet synchronous motor, and acquiring real-time D-axis current; and adjusting the initial Q-axis current according to the first estimated position and the real-time D-axis current to obtain a target Q-axis current, and controlling the permanent magnet synchronous motor according to the target Q-axis current so as to enable the permanent magnet synchronous motor to reach a closed-loop running state. By adopting the embodiment of the application, the permanent magnet synchronous motor can quickly reach a closed-loop running state after being started.

Description

Control method and device of permanent magnet synchronous motor, electronic equipment and storage medium

Technical Field

The present disclosure relates to the field of motor control, and in particular, to a method and apparatus for controlling a permanent magnet synchronous motor, an electronic device, and a storage medium.

Background

The traditional permanent magnet synchronous motor starting method mostly adopts open loop control, namely, the initial current is preset according to motor parameters and is directly applied to the motor to realize starting. The method is simple to start, but the rotor position cannot be effectively detected and tracked in the starting process, so that the problem that the rotor rotates reversely or oscillates after the motor is started is solved, and the permanent magnet synchronous motor is not beneficial to quickly achieving a stable closed-loop running state.

Disclosure of Invention

The application provides a control method, a control device, electronic equipment and a storage medium of a permanent magnet synchronous motor, which can enable the permanent magnet synchronous motor to quickly reach a closed-loop running state after being started.

In a first aspect of the present application, the present application provides a control method of a permanent magnet synchronous motor, including:

starting the permanent magnet synchronous motor according to initial parameters, wherein the initial parameters comprise a forced position and an initial Q-axis current;

when the permanent magnet synchronous motor is in a starting state, calculating a first estimated position of the permanent magnet synchronous motor, and acquiring real-time D-axis current;

and adjusting the initial Q-axis current according to the first estimated position and the real-time D-axis current to obtain a target Q-axis current, and controlling the permanent magnet synchronous motor according to the target Q-axis current so as to enable the permanent magnet synchronous motor to reach a closed-loop running state.

By adopting the technical scheme, the open-loop starting control of the permanent magnet synchronous motor is realized according to the preset forced position and the initial Q-axis current at the initial starting stage, so that the motor starts to accelerate from a static state. After the motor reaches a start state, a first estimated position of the motor is calculated using an observer algorithm. This results in a non-zero current on the D-axis due to the fact that the forced position used for open loop starting is different from the actual initial position of the motor. To achieve a smooth transition from open loop control to vector control of the magnetic rotating machine, the initial Q-axis current needs to be adjusted according to the first estimated position and the D-axis real-time current to obtain a smooth target Q-axis current to compensate for the effect of the position difference. Finally, the closed-loop control of the permanent magnet synchronous motor is realized according to the adjusted target Q-axis current, so that the motor operates in a stable closed-loop state. The smooth transition between the non-inductive start of the motor and the vector closed-loop control is realized when the initial position of the motor is not known. In the starting stage, the open-loop control starting is realized by preset parameters, in the transition stage, the position error is effectively compensated by adjusting the current of the Q axis, and in the closed-loop stage, the vector closed-loop control is realized. The whole process of the scheme is stable and effective, so that the motor can finally and stably run in a specified closed-loop control mode from a static state, and the non-inductive start and stable transition are achieved.

Optionally, the adjusting the initial Q-axis current according to the estimated position and the real-time D-axis current to obtain a target Q-axis current includes:

calculating the difference between the first estimated position and the forced position to obtain a deviation position;

judging whether the deviation position is smaller than a first threshold value and whether the real-time D-axis current is smaller than a second threshold value;

and if the deviation position is smaller than the first threshold value and the real-time D-axis current is smaller than the second threshold value, determining the initial Q-axis current as the target Q-axis current.

By adopting the technical scheme, the difference between the first estimated position and the forced position is calculated, and a deviation position representing the angular deviation between the first estimated position and the forced position is obtained. And then setting a deviation position and a reasonable threshold value of the real-time D-axis current, and determining whether the initial Q-axis current can be directly used as the target Q-axis current by judging whether the deviation position is smaller than the threshold value and whether the D-axis current is smaller than the threshold value. If both the deviation position and the D-axis current meet the threshold requirements, the first estimated position is close enough to the initial position, the D-axis current is basically close to zero, and the initial Q-axis current is directly determined as the target Q-axis current, so that smooth transition to closed-loop control is realized.

The approach degree of the first estimated position and the initial position is judged by calculating the deviation position, a threshold condition is set to determine whether the initial Q-axis current needs to be adjusted, the initial Q-axis current is directly adopted only when the position error and the D-axis current are within the allowable range, and the setting threshold judgment mode can prevent blind adoption of the initial Q-axis current when the error is overlarge, so that the target Q-axis current matched with the actual position error is obtained.

Optionally, the method further comprises:

if the deviation position is larger than or equal to the first threshold value or the real-time D-axis current is larger than or equal to the second threshold value, the initial Q-axis current is reduced by a target current value, and a first Q-axis current is obtained;

and controlling the permanent magnet synchronous motor according to the first Q-axis current, and re-executing the steps of calculating a first estimated position of the permanent magnet synchronous motor and obtaining real-time D-axis current until the deviation position is smaller than the first threshold value or the real-time D-axis current is smaller than the second threshold value to obtain the target Q-axis current.

By adopting the technical scheme, if the deviation position is judged to be greater than or equal to the threshold value, or the real-time D-axis current is judged to be greater than or equal to the threshold value, the fact that a larger position error or D-axis current exists is indicated, and the initial Q-axis current needs to be continuously adjusted. In this case, the scheme steps down the initial Q-axis current by the target current value to obtain a new first Q-axis current, and controls the motor according to the first Q-axis current. At the same time, the steps of calculating the first estimated position and acquiring the real-time D-axis current are re-performed. And gradually reducing the initial Q-axis current by repeating the operation, the adjustment and the control until the deviation position is smaller than the threshold value or the D-axis current is smaller than the threshold value, and stopping the adjustment, wherein the initial Q-axis current is the final target Q-axis current.

The progressive optimization of the initial Q-axis current is realized, and finally the target Q-axis current matched with the actual position error of the motor is obtained. The Q-axis current is continuously adjusted when there is a large error, and the adjustment is terminated when the error is judged to be within the allowable range.

Optionally, the reducing the initial Q-axis current by a target current value includes:

judging whether the permanent magnet synchronous motor runs stably or not;

if the permanent magnet synchronous motor runs stably, taking a first current value as the target current value, and reducing the initial Q-axis current by the target current value;

and if the operation of the permanent magnet synchronous motor is unstable, taking a second current value as the target current value, and reducing the initial Q-axis current by the target current value, wherein the second current value is smaller than the first current value.

By adopting the technical scheme, if the motor is judged to be stable in operation, a larger first current value is set as a target current value to quickly reduce the initial Q-axis current, and if the motor is judged to be unstable in operation, a smaller second current value is set as a target current value to slowly reduce the initial Q-axis current.

By judging the running stability of the motor and adopting a target current value matched with the motor and a corresponding speed strategy for reducing the initial Q-axis current, the system instability can be avoided when the initial Q-axis current is regulated. When the motor is running stably, a larger current value can be used for quick adjustment, and when the motor is running unstably, a smaller current value is used for slow adjustment. The strategy comprehensively considers the regulating speed and the system stability, and adopts the optimal regulating parameters according to the stability condition of the motor on the premise of ensuring stable transition, thereby realizing stable and effective regulation of the initial Q-axis current.

Optionally, the initial parameter further includes an initial D-axis current, and the initial D-axis current is 0.

By adopting the above technical scheme, in addition to the forced position and the initial Q-axis current, the initial D-axis current may be additionally added to the initial parameters of the present control method, and set to 0. This results in a non-zero current on the D-axis, since the forced position is different from the actual initial position of the motor at the time of open loop start control. Therefore, by additionally designating the D-axis current as 0 in the initial parameter, the generation of the D-axis current can be suppressed, and the D-axis current component can be reduced as much as possible.

The arrangement can alleviate current fluctuation caused by position error, and is beneficial to smoother starting process. When the D-axis current is designated as 0, the motor can still obtain enough starting torque from the Q-axis current, and the observed D-axis current also reflects the position difference more accurately, which is beneficial for subsequent smooth transition to closed-loop control.

Optionally, the calculating the first estimated position of the permanent magnet synchronous motor includes:

acquiring a first current and a first voltage of the permanent magnet synchronous motor, and performing Clark conversion on the first current and the first voltage to obtain a second current and a second voltage;

Performing Park conversion on the second current and the second voltage to obtain a third current and a third voltage;

and acquiring a fourth current and a fourth voltage obtained by the permanent magnet synchronous motor based on the third current and the third voltage control observer, and obtaining the first estimated position according to the fourth current and the fourth voltage.

By adopting the technical scheme, the position estimation under the condition of open loop starting of the motor is realized by means of series connection application of Clark conversion, park conversion, observer algorithm and the like. The method comprises the steps of firstly obtaining current and voltage information of a motor, and then converting a three-phase static coordinate system into a two-dimensional alpha beta coordinate system by Clark transformation so as to reduce the calculated amount and facilitate the operation of a follow-up observer. And then transferring the alpha beta coordinate to a dq coordinate system consistent with the motor rotation coordinate system through Park transformation so as to facilitate the application of an observer algorithm designed for the dq coordinate. And then, inputting the current and voltage quantities into an observer under the dq coordinates, observing and estimating the state of the motor through an observer algorithm, and finally outputting a first estimated position of the motor. The whole calculation process fully utilizes the principles of coordinate transformation and a state observer, converts the static three-phase coordinate into a rotating dq coordinate, obtains the position information of the motor under the rotating coordinate system through an observer algorithm, realizes effective estimation of the initial position of the motor under the open-loop starting condition, and creates conditions for subsequent closed-loop control.

In a second aspect of the present application, there is provided a control device for a permanent magnet synchronous motor, comprising:

the permanent magnet synchronous motor starting module is used for starting the permanent magnet synchronous motor according to initial parameters, wherein the initial parameters comprise a forced position and an initial Q-axis current;

the first estimated position calculation module is used for calculating a first estimated position of the permanent magnet synchronous motor and acquiring real-time D-axis current when the permanent magnet synchronous motor is in a starting state;

and the permanent magnet synchronous motor closed-loop control module is used for adjusting the initial Q-axis current according to the first estimated position and the real-time D-axis current to obtain a target Q-axis current, and controlling the permanent magnet synchronous motor according to the target Q-axis current so as to enable the permanent magnet synchronous motor to reach a closed-loop running state.

Optionally, the closed-loop control module of the permanent magnet synchronous motor is further configured to calculate a difference between the first estimated position and the forced position to obtain a deviation position; judging whether the deviation position is smaller than a first threshold value and whether the real-time D-axis current is smaller than a second threshold value; and if the deviation position is smaller than the first threshold value and the real-time D-axis current is smaller than the second threshold value, determining the initial Q-axis current as the target Q-axis current.

In a third aspect the present application provides a computer storage medium storing a plurality of instructions adapted to be loaded by a processor and to perform the above-described method steps.

In a fourth aspect of the present application, there is provided an electronic device comprising: a processor, a memory; wherein the memory stores a computer program adapted to be loaded by the processor and to perform the above-mentioned method steps.

In summary, one or more technical solutions provided in the embodiments of the present application at least have the following technical effects or advantages:

Drawings

Fig. 1 is a flow chart of a control method of a permanent magnet synchronous motor according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a control device of a permanent magnet synchronous motor according to an embodiment of the present application.

Fig. 3 is a schematic structural diagram of an electronic device according to the disclosure in an embodiment of the present application.

Reference numerals illustrate: 300. an electronic device; 301. a processor; 302. a communication bus; 303. a user interface; 304. a network interface; 305. a memory.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present specification, the technical solutions in the embodiments of the present specification will be clearly and completely described below with reference to the drawings in the embodiments of the present specification, and it is obvious that the described embodiments are only some embodiments of the present application, but not all embodiments.

In the description of embodiments of the present application, words such as "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described herein as "such as" or "for example" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "or" for example "is intended to present related concepts in a concrete fashion.

In the description of the embodiments of the present application, the term "plurality" means two or more. For example, a plurality of systems means two or more systems, and a plurality of screen terminals means two or more screen terminals. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating an indicated technical feature. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

The embodiment of the application provides a control method of a permanent magnet synchronous motor. In an embodiment, please refer to fig. 1, fig. 1 is a flow chart of a control method of a permanent magnet synchronous motor according to an embodiment of the present application, where the method may be implemented by a computer program, may be implemented by a single chip microcomputer, or may be run on a control device of a permanent magnet synchronous motor based on von neumann system. The computer program may be integrated in the application or may run as a stand-alone tool class application. Specifically, the method may include the steps of:

Step 101: starting the permanent magnet synchronous motor according to initial parameters, wherein the initial parameters comprise forced position and initial Q-axis current.

The initial parameters refer to control parameters that need to be preset when starting the permanent magnet synchronous motor, and in the embodiment of the application, the initial Q-axis current and the forced position can be understood to be used for starting the motor through open loop control and accelerating the motor without knowing the actual position of the motor.

The forced position refers to motor position information manually assigned to the inverter during the open loop starting stage, which can be understood as θ_force in the embodiment of the present application, and is used to calculate a voltage space vector according to the virtual position and apply the voltage space vector to the motor when the actual position of the motor is not known yet, so as to realize open loop starting control of the motor.

Specifically, it may be a position value arbitrarily set before starting, used as motor position information under FOC control, and the Q-axis and D-axis voltage components of the inverter are calculated from θ_force and applied to the motor to start acceleration operation by generating torque from the motor. But because theta _ for is not equal to the true angular position theta _ real, a non-zero current will be induced on the D-axis. The setting of θ_for enables the system to start the motor when the actual position of the motor is not known, but also introduces a position error, which is one of the key parameters for realizing open loop start control.

The initial Q-axis current refers to a Q-axis current reference value assigned to the inverter during an open loop start-up phase, which in this embodiment may be understood as iq_init, for providing the torque required by the motor to start accelerating the motor from a stationary state.

Specifically, iq_init is a Q-axis current magnitude preset under open loop control, and is input to the inverter as an Iq command for FOC control. The voltage vector corresponding to the virtual position θ_for is calculated according to the virtual position θ_for, and the inverter applies the voltage vector to the motor. The motor generates torque according to the voltage and supplies a set iq_init current to the Q-axis. The D-axis current is not zero at this time, but the motor can continue to acquire torque and begin accelerating. The setting of iq_init enables the start-up operation of the motor under open loop conditions.

Further, to achieve a smooth transition from the open-loop mode to the closed-loop mode, the permanent magnet synchronous motor needs to be started first. When the motor is started, the initial position of the motor is not known, so that vector control cannot be performed, and only open-loop control can be adopted. Therefore, an initial Q-axis current iq_init is set as a power current reference, a forced position θ_forc is assumed as an initial position of the motor, and then a corresponding voltage space vector is calculated according to θ_forc, and is applied to the motor through the inverter to accelerate the motor from a stationary state under the action of iq_init. At this point θ_for is different from the true angular position θ_real of the motor, so a non-zero current Id is generated on the motor D-axis. Although the difference between θ_for and θ_real may cause a certain jitter during the motor start-up process, the motor may reach a stable acceleration state. In this way, by presetting two initial parameters, namely the initial Q-axis current Iq_init and the virtual position theta_forc, open-loop starting control of the motor can be realized, and conditions are created for the subsequent smooth transition to the closed-loop mode.

On the basis of the above embodiment, as an alternative embodiment, the initial parameter further includes an initial D-axis current, and the initial D-axis current is 0.

After setting the initial Q-axis current reference iq_init, the D-axis current reference id_init is additionally specified to be 0 and input into the inverter. And then, calculating a corresponding voltage vector according to the virtual position theta_forc, and outputting the voltage vector to the motor through the inverter. The motor D-axis would otherwise produce a non-zero current, but now forcing a given id_init=0 would suppress the production of D-axis current.

The purpose of this is to reduce current jitter caused by the virtual position θ_for being different from the real position θ_real during open loop start. Specifying id_init=0 can reduce the D-axis current component as much as possible, contributing to a smoother starting process.

When id_init=0, the motor can still obtain sufficient torque starting from iq_init. The observed D-axis current Id is closer to 0, and the position difference is reflected more accurately, so that the follow-up closed-loop switching control is facilitated. To sum up, setting id_init=0 can make the open loop start smoother and obtain more accurate feedback current, and helps to realize smooth transition control of the motor.

Step 102: when the permanent magnet synchronous motor is in a starting state, a first estimated position of the permanent magnet synchronous motor is calculated, and real-time D-axis current is obtained.

The real-time D-axis current refers to a real-time current value of the D-axis of the motor during the operation process, and in the embodiment of the present application, id may be understood as Id, which is used to reflect a difference between the forced position θ_for and the actual position θ_real of the motor.

Specifically, id is the magnitude of the current of the D-axis component in the motor dq coordinates. At open loop start, since the designated θ_for is not equal to θ_real, the voltage vector calculated from θ_for has a certain deviation from the rotor position of the motor, resulting in a non-zero Id on the motor D-axis. The larger Id means that the larger the difference between θ_forc and θ_real. Therefore, detecting the Id can determine the deviation between θ_for and the actual motor position θ_real, which is one of the important parameters for realizing smooth switching to closed-loop control. By acquiring the Id feedback, the control amount can be adjusted to compensate for the effect of the positional deviation.

The first estimated position refers to a motor position obtained by first estimating the motor through an observer algorithm after the motor is started in an open loop, and may be understood as θ_est1 in the embodiment of the present application, and is used to represent an initial estimated position of the motor.

Specifically, θ_est1 is an estimated value of the initial position of the motor calculated by a state observer according to current and voltage feedback during the open loop starting process of the motor. Because there is no position information for closed loop feedback at this time, θ_est1 may deviate from the true angular position θ_real by some amount. But theta _ est1 may reflect a relatively reliable motor initial position. The purpose of acquiring θ_est1 is to realize a smooth transition from open-loop control to closed-loop control by utilizing the difference between it and the forced position θ_for when the control parameter is subsequently adjusted.

Based on the above embodiment, as an alternative embodiment, in step 102: the step of calculating the first estimated position of the permanent magnet synchronous motor may specifically further comprise the steps of:

step 201: and obtaining a first current and a first voltage of the permanent magnet synchronous motor, and performing Clark conversion on the first current and the first voltage to obtain a second current and a second voltage.

Specifically, in order to calculate the first estimated position θest1 of the motor, it is first necessary to acquire current and voltage information of the motor. Specifically, three-phase currents ia, ib and ic of the motor are collected through a current-voltage sensor to serve as first currents, and three-phase voltages va, vb and vc serve as first voltages. And then carrying out coordinate transformation on the three-phase currents and voltages according to a Clark transformation matrix, converting the three-phase currents and voltages into an alpha beta static coordinate system, and obtaining second currents I alpha and I beta and second voltages V alpha and V beta of the motor under the alpha beta coordinate system. The Clark transformation is performed to facilitate the calculation of θest1 based on the subsequent observer algorithm of the alpha beta coordinate, and the transformation to the two-dimensional coordinate system can also reduce the calculation amount. The current and voltage information in the αβ coordinate system can be obtained by Clark transformation, which are the measurement inputs required by the observer to calculate the first estimated position θest 1.

Step 202: and performing Park conversion on the second current and the second voltage to obtain a third current and a third voltage.

Specifically, in order to calculate the first estimated position θest1 of the motor, after Clark transformation is performed, the second currents ia and I β and the second voltages vα and vβ under the αβ stationary coordinate system obtained by Clark transformation are also required to be used as inputs, and then converted into the dq rotating coordinate system consistent with the motor rotating coordinate system through the Park transformation matrix, so that an observer algorithm designed for the dq coordinate system can be applied. After Park conversion, the third currents Id, iq and the third voltages Vd, vq of the motor are obtained in the dq coordinate system. Park transformation is a key coordinate transformation step in the process of calculating θest1, and current and voltage data in dq coordinates are obtained through transformation, and are all measurement inputs required by an observer for calculating θest 1. Coordinate transformation is realized through Park transformation, and current and voltage under dq coordinates required for calculating the first estimated position θest1 are obtained.

Step 203: and acquiring a fourth current and a fourth voltage obtained by the permanent magnet synchronous motor based on the third current and the third voltage control observer, and obtaining a first estimated position according to the fourth current and the fourth voltage.

Specifically, in order to calculate the first estimated position θest1 of the motor, it is also necessary to observe and estimate the position of the motor using an observer algorithm after Park conversion is performed. The method comprises the steps of inputting a third current and a third voltage under dq coordinates obtained by Park transformation into an observer, and observing and collecting a fourth current and a fourth voltage of the motor by the observer based on a current/voltage model by adopting a state observation method. Finally, the observer calculates a first estimated position θest1 of the motor according to the fourth current and the fourth voltage obtained by observation through calculation and operation. This is because the position information of the motor cannot be directly acquired during the open loop starting process, and the position of the motor needs to be indirectly calculated based on the state observation of the current and the voltage by the observer algorithm. Therefore, the operation of the observer is an indispensable key step in the open loop starting control process, and finally the first estimated position θest1 of the motor can be output to complete the position estimation task.

Step 103: and adjusting the initial Q-axis current according to the first estimated position and the real-time D-axis current to obtain a target Q-axis current, and controlling the permanent magnet synchronous motor according to the target Q-axis current so as to enable the permanent magnet synchronous motor to reach a closed-loop running state.

After the motor is started open loop, the first estimated position θ_est1 has been calculated by the above steps, and the real-time D-axis current Id is obtained. This can result in an observed Id that is not equal to 0 due to the difference between the forced position θ_forc used at open loop start and the actual initial motor position θ_real. In order to achieve a smooth transition from open loop control to magnetic rotating machine vector control, it is necessary to adjust the initial Q-axis current iq_init according to θ_est1 and Id to obtain a smooth target Q-axis current iq_target to compensate for the effect of the position difference.

Specifically, first, the positional deviation Δθ=θ_est1- θ_forc between θ_est1 and θ_forc is calculated. When Δθ approaches 0, it means that θ_est1 has trended toward the true angular position θ_real. Meanwhile, the real-time D-axis current Id is detected, and Id also tends to be 0. Iq_init can be adjusted according to the magnitude of Δθ and Id to smoothly decrease to a new target value iq_target to decrease Id. This can effectively suppress current fluctuations due to Δθ.

For example, the thresholds Dth for Δθ and Ith for Id may be set, when Δθ < Dth and Id < Ith, then let iq_target equal the current iq_init. If not, iq_init may be gradually reduced until the condition is met, in this way a smooth Iq_target is obtained.

After obtaining a stable target Q-axis current Iq_target, the motor is controlled in a closed loop mode according to the Iq_target, and the motor is input as Iq command quantity of subsequent vector control. The stable transition from open-loop control to closed-loop control is completed by adjusting the current of the Q axis, so that the motor operates in a stable closed-loop state, and conditions are created for subsequent vector feedback control.

On the basis of the above embodiment, as an alternative embodiment, in step 103: according to the estimated position and the real-time D-axis current, the step of adjusting the initial Q-axis current to obtain the target Q-axis current may further include the steps of:

step 201: and calculating the difference between the first estimated position and the forced position to obtain a deviation position.

In order to adjust the initial Q-axis current iq_init according to the difference between the first estimated position θ_est1 and the forced position θ_for, it is first necessary to quantify the positional deviation therebetween.

Specifically, by calculating the difference between θ_est1 and θ_for, a deviation position Δθ representing the angular deviation therebetween, that is, Δθ=θ_est1- θ_for can be obtained. The purpose of calculating Δθ is to quantify the degree of mismatch between θ_est1 and θ_for.

At open loop start, θ_forc is the initial virtual position set by the person, and θ_est1 is the position estimate calculated by the observer after start. θ_est1 is relatively closer to the actual initial motor position θ_real. Δθ reflects the error of θ_for relative to θ_real.

By calculating Δθ, the severity of the positional deviation can be determined based on the magnitude of Δθ, and iq_init adjusted accordingly to compensate for the effects of the discrepancy, achieving a smooth transition to closed loop control. If Δθ approaches 0, it is indicated that θ_est1 is already approaching θ_real, and the difference is not large, which is suitable for switching directly to closed loop. If Δθ is large, it is necessary to adjust iq_init stepwise to reduce the effect of the difference.

Step 202: and judging whether the deviation position is smaller than a first threshold value and whether the real-time D-axis current is smaller than a second threshold value.

Step 203: and if the deviation position is smaller than the first threshold value and the real-time D-axis current is smaller than the second threshold value, determining the initial Q-axis current as the target Q-axis current.

To determine whether the initial Q-axis current iq_init can be directly taken as the target current, it is necessary to quantify whether the magnitudes of the position deviation Δθ and the real-time D-axis current Id satisfy the requirements.

Specifically, a reasonable threshold Dth of Δθ is set first, and when Δθ < Dth, it is considered that the difference between θ_est1 and θ_real is already within the allowable range. At the same time, a reasonable threshold Ith for Id is set, and when Id < Ith, the influence of the positioning deviation on Id is considered acceptable.

Then, it is judged whether the calculated actual Δθ is smaller than a threshold Dth, and whether the detected real-time Id is smaller than a threshold Ith. If both Δθ and Id satisfy the above conditions, then it is stated that the current Iq_init has made θ_est1 sufficiently close to θ_real, id also substantially close to zero, and the difference has negligible effect on control.

In this case, in order to smoothly transition to the closed-loop control, the current iq_init may be directly set as the target Q-axis current iq_target, that is, iq_target=iq_init is determined, and then the subsequent closed-loop control is performed according to this iq_target without readjusting iq_init.

If either Δθ or Id does not meet the above conditions, it is also necessary to continue to adjust Iq_init so that Δθ and Id are further reduced, at which point the current Iq_init cannot be taken directly as Iq_target.

Step 204: and if the deviation position is greater than or equal to a first threshold value or the real-time D-axis current is greater than or equal to a second threshold value, reducing the initial Q-axis current by a target current value to obtain a first Q-axis current.

Step 205: and controlling the permanent magnet synchronous motor according to the first Q-axis current, and re-executing the steps of calculating the first estimated position of the permanent magnet synchronous motor and acquiring the real-time D-axis current until the deviation position is smaller than a first threshold value or the real-time D-axis current is smaller than a second threshold value to obtain the target Q-axis current.

If the delta theta is judged to be greater than or equal to the threshold value Dth or the Id is judged to be greater than or equal to the threshold value Ith, the current Iq_init is required to be adjusted and optimized, and then smooth transition to closed-loop control can be realized.

Specifically, iq_init needs to be reduced first to mitigate the effect of the discrepancy. The decreasing amplitude may set a target current value and decrease iq_init by the target value to obtain a new first Q-axis current Iq1. Then, motor control is performed based on the newly obtained Iq1 instead of iq_init, so that the motor continues to operate at the new Iq1. At the same time, the calculation of the first estimated position θ_est1 and the value acquisition of the real-time Id are re-performed. And judging the recalculated delta theta and the detected Id according to a threshold criterion. If the conditions Δθ < Dth and Id < Ith are not yet satisfied, the iq_init continues to be reduced, and the above operation is repeated until the conditions are satisfied. When both delta theta and Id meet the threshold condition, the current Iq_init is the final target Q-axis current Iq_target. By gradually reducing Iq_init, firstly enabling delta theta and Id to tend to a threshold value, and then terminating adjustment when the conditions are met, and finally obtaining a stable Iq_target, thereby realizing smooth transition to closed-loop control.

Based on the above embodiment, as an alternative embodiment, in step 204: the step of reducing the initial Q-axis current by the target current value may specifically further include the steps of:

step 301: judging whether the permanent magnet synchronous motor runs stably or not.

Step 302: and if the permanent magnet synchronous motor runs stably, taking the first current value as a target current value, and reducing the initial Q-axis current by the target current value.

Step 303: and if the permanent magnet synchronous motor is unstable in operation, taking the second current value as a target current value, and reducing the initial Q-axis current by the target current value, wherein the second current value is smaller than the first current value.

In order to smoothly reduce iq_init, the operation stability of the motor needs to be considered. Iq_init can be adjusted faster if the motor is running steady, and Iq_init needs to be adjusted slowly if the motor is running unsteady.

Specifically, it is first determined whether the actual operation of the motor is stable. Stability can be judged according to current and rotation speed fluctuation. If the motor is judged to be stable in operation, a larger first current value is set as a target current value, and Iq_init is reduced faster according to the target value, so that Iq_init is regulated to a larger extent. If the motor is judged to be running unstably, slow adjustment is required. At this time, a smaller second current value is set as a target current value, and iq_init is slowly reduced according to the smaller target value, so that the iq_init is regulated more smoothly. The speed of the amplitude reduction depends on the operation stability, and the stable reduction of Iq_init can achieve the target requirement without causing instability of the system. The fast adjustment can be optimized faster during stable state, and the slow adjustment can ensure stable transition during unstable state.

Therefore, the target current value for reducing Iq_init is determined according to the real-time running stability condition of the motor, and the speed of reducing the amplitude is correspondingly adjusted, so that stable optimization adjustment of Iq_init can be realized, the adjustment effect is ensured, and instability is prevented.

Referring to fig. 2, the present application further provides a control device of a permanent magnet synchronous motor, including:

On the basis of the above embodiment, as an optional embodiment, the closed-loop control module of the permanent magnet synchronous motor is further configured to calculate a difference between the first estimated position and the forced position to obtain a deviation position; judging whether the deviation position is smaller than a first threshold value and whether the real-time D-axis current is smaller than a second threshold value; and if the deviation position is smaller than the first threshold value and the real-time D-axis current is smaller than the second threshold value, determining the initial Q-axis current as the target Q-axis current.

On the basis of the foregoing embodiment, as an optional embodiment, the closed-loop control module of the permanent magnet synchronous motor is further configured to reduce the initial Q-axis current by a target current value if the deviation position is greater than or equal to the first threshold value, or if the real-time D-axis current is greater than or equal to the second threshold value, to obtain a first Q-axis current; and controlling the permanent magnet synchronous motor according to the first Q-axis current, and re-executing the steps of calculating a first estimated position of the permanent magnet synchronous motor and obtaining real-time D-axis current until the deviation position is smaller than the first threshold value or the real-time D-axis current is smaller than the second threshold value to obtain the target Q-axis current.

On the basis of the above embodiment, as an optional embodiment, the closed-loop control module of the permanent magnet synchronous motor is further configured to determine whether the permanent magnet synchronous motor is stable in operation; if the permanent magnet synchronous motor runs stably, taking a first current value as the target current value, and reducing the initial Q-axis current by the target current value; and if the operation of the permanent magnet synchronous motor is unstable, taking a second current value as the target current value, and reducing the initial Q-axis current by the target current value, wherein the second current value is smaller than the first current value.

Based on the above embodiment, as an optional embodiment, the first estimated position calculation module is further configured to obtain a first current and a first voltage of the permanent magnet synchronous motor, and perform Clark transformation on the first current and the first voltage to obtain a second current and a second voltage; performing Park conversion on the second current and the second voltage to obtain a third current and a third voltage; and acquiring a fourth current and a fourth voltage obtained by the permanent magnet synchronous motor based on the third current and the third voltage control observer, and obtaining the first estimated position according to the fourth current and the fourth voltage.

It should be noted that: in the device provided in the above embodiment, when implementing the functions thereof, only the division of the above functional modules is used as an example, in practical application, the above functional allocation may be implemented by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules, so as to implement all or part of the functions described above. In addition, the embodiments of the apparatus and the method provided in the foregoing embodiments belong to the same concept, and specific implementation processes of the embodiments of the method are detailed in the method embodiments, which are not repeated herein.

The embodiment of the present application further provides a computer storage medium, where the computer storage medium may store a plurality of instructions, where the instructions are adapted to be loaded and executed by a processor, where the specific execution process may refer to the specific description of the illustrated embodiment, and details are not repeated herein.

The application also discloses electronic equipment. Referring to fig. 3, fig. 3 is a schematic structural diagram of an electronic device according to the disclosure in an embodiment of the present application. The electronic device 300 may include: at least one processor 301, at least one network interface 304, a user interface 303, a memory 305, at least one communication bus 302.

Wherein the communication bus 302 is used to enable connected communication between these components.

The user interface 303 may include a Display screen (Display) interface and a Camera (Camera) interface, and the optional user interface 303 may further include a standard wired interface and a standard wireless interface.

The network interface 304 may optionally include a standard wired interface, a wireless interface (e.g., WI-FI interface), among others.

Wherein the processor 301 may include one or more processing cores. The processor 301 utilizes various interfaces and lines to connect various portions of the overall server, perform various functions of the server and process data by executing or executing instructions, programs, code sets, or instruction sets stored in the memory 305, and invoking data stored in the memory 305. Alternatively, the processor 301 may be implemented in hardware in at least one of digital signal processing (Digital Signal Processing, DSP), field programmable gate array (Field-Programmable Gate Array, FPGA), programmable logic array (Programmable Logic Array, PLA). The processor 301 may integrate one or a combination of several of a central processing unit (Central Processing Unit, CPU), an image processor (Graphics Processing Unit, GPU), and a modem etc. The CPU mainly processes an operating system, a user interface diagram, an application program and the like; the GPU is used for rendering and drawing the content required to be displayed by the display screen; the modem is used to handle wireless communications. It will be appreciated that the modem may not be integrated into the processor 301 and may be implemented by a single chip.

The Memory 305 may include a random access Memory (Random Access Memory, RAM) or a Read-Only Memory (Read-Only Memory). Optionally, the memory 305 includes a non-transitory computer readable medium (non-transitory computer-readable storage medium). Memory 305 may be used to store instructions, programs, code, sets of codes, or sets of instructions. The memory 305 may include a stored program area and a stored data area, wherein the stored program area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playing function, an image playing function, etc.), instructions for implementing the above-described respective method embodiments, etc.; the storage data area may store data or the like involved in the above respective method embodiments. Memory 305 may also optionally be at least one storage device located remotely from the aforementioned processor 301. Referring to fig. 3, an operating system, a network communication module, a user interface module, and an application program of a control method of a permanent magnet synchronous motor may be included in the memory 305 as a computer storage medium.

In the electronic device 300 shown in fig. 3, the user interface 303 is mainly used for providing an input interface for a user, and acquiring data input by the user; and the processor 301 may be used to invoke an application program in the memory 305 that stores a method of controlling a permanent magnet synchronous motor, which when executed by the one or more processors 301, causes the electronic device 300 to perform the method as described in one or more of the embodiments above. It should be noted that, for simplicity of description, the foregoing method embodiments are all expressed as a series of action combinations, but it should be understood by those skilled in the art that the present application is not limited by the order of actions described, as some steps may be performed in other order or simultaneously in accordance with the present application. Further, those skilled in the art will also appreciate that the embodiments described in the specification are all preferred embodiments, and that the acts and modules referred to are not necessarily required in the present application.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

In the several embodiments provided herein, it should be understood that the disclosed apparatus may be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative, such as a division of units, merely a division of logic functions, and there may be additional divisions in actual implementation, such as multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some service interface, device or unit indirect coupling or communication connection, electrical or otherwise.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable memory. Based on such understanding, the technical solution of the present application may be embodied in essence or a part contributing to the prior art or all or part of the technical solution in the form of a software product stored in a memory, including several instructions for causing a computer device (which may be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the methods of the embodiments of the present application. And the aforementioned memory includes: various media capable of storing program codes, such as a U disk, a mobile hard disk, a magnetic disk or an optical disk.

The foregoing is merely exemplary embodiments of the present disclosure and is not intended to limit the scope of the present disclosure. That is, equivalent changes and modifications are contemplated by the teachings of this disclosure, which fall within the scope of the present disclosure. Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure.

This application is intended to cover any adaptations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a scope and spirit of the disclosure being indicated by the claims.

Claims

1. A control method of a permanent magnet synchronous motor, characterized by comprising:

starting a permanent magnet synchronous motor according to initial parameters, wherein the initial parameters comprise a forced position and an initial Q-axis current;

2. The method of claim 1, wherein adjusting the initial Q-axis current based on the estimated position and the real-time D-axis current to obtain a target Q-axis current comprises:

3. The control method of a permanent magnet synchronous motor according to claim 2, characterized in that the method further comprises:

4. The control method of a permanent magnet synchronous motor according to claim 3, wherein the reducing the initial Q-axis current by a target current value includes:

Judging whether the permanent magnet synchronous motor runs stably or not;

5. The method of claim 1, wherein the initial parameters further comprise an initial D-axis current, the initial D-axis current being 0.

6. The method of controlling a permanent magnet synchronous motor according to claim 1, wherein the calculating a first estimated position of the permanent magnet synchronous motor includes:

7. A control device for a permanent magnet synchronous motor, comprising:

8. The control device of a permanent magnet synchronous motor according to claim 7, wherein the closed-loop control module of the permanent magnet synchronous motor is further configured to calculate a difference between the first estimated position and the forced position to obtain a deviation position; judging whether the deviation position is smaller than a first threshold value and whether the real-time D-axis current is smaller than a second threshold value; and if the deviation position is smaller than the first threshold value and the real-time D-axis current is smaller than the second threshold value, determining the initial Q-axis current as the target Q-axis current.

9. An electronic device comprising a processor, a memory, a user interface, and a network interface, the memory for storing instructions, the user interface and the network interface for communicating to other devices, the processor for executing the instructions stored in the memory to cause the electronic device to perform the method of any of claims 1-7.

10. A computer storage medium storing instructions which, when executed, perform the method of any one of claims 1-7.