阅读说明：本技术 一种基于功角自平衡特性的开环启动策略 (Open-loop starting strategy based on power angle self-balancing characteristic ) 是由 董培培 柯超 曹坤 于 2020-06-15 设计创作，主要内容包括：本发明涉及一种基于功角自平衡特性的开环启动策略,将速度环、电流环处于开环条件,d轴电压<Image he="47" wi="139" file="RE-385312DEST_PATH_IMAGE001.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,<Image he="32" wi="44" file="RE-696339DEST_PATH_IMAGE002.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>为对齐期望电压,q轴电压<Image he="30" wi="58" file="RE-999144DEST_PATH_IMAGE003.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,期望位置角<Image he="11" wi="57" file="RE-31341DEST_PATH_IMAGE004.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>°；施加一个与期望位置角相差90°方向的电压矢量,转子转动到期望位置角；撤掉d轴期望电压,进入开环启动阶段；将速度环处于开环,电流环处于闭环条件,d轴期望电流<Image he="18" wi="37" file="RE-241743DEST_PATH_IMAGE005.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,将q轴电流<Image he="27" wi="17" file="RE-407276DEST_PATH_IMAGE006.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>加到期望最大电流<Image he="40" wi="46" file="RE-287507DEST_PATH_IMAGE007.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,期望加速度<Image he="9" wi="48" file="RE-787759DEST_PATH_IMAGE009.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,角速度<Image he="33" wi="75" file="RE-287004DEST_PATH_IMAGE010.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,角度<Image he="30" wi="98" file="RE-821891DEST_PATH_IMAGE011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>；q轴电流<Image he="28" wi="21" file="RE-151985DEST_PATH_IMAGE012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>保持为期望最大电流<Image he="32" wi="47" file="RE-139532DEST_PATH_IMAGE013.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>,当角速度大于最小观测速度<Image he="22" wi="48" file="RE-567102DEST_PATH_IMAGE014.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>时,开启观测器；q轴电流<Image he="25" wi="18" file="RE-972807DEST_PATH_IMAGE015.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>由期望最大电流<Image he="33" wi="48" file="100004_RE-RE-DEST_PATH_IMAGE016.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>减小,将观测器观测到的角度和角速度与期望角度和角速度对比,满足切换阈值,进行闭环切换。本发明的开环启动策略,解决了现有电机在低速条件时,适用性差及启动和切换时扭矩脉动等缺陷。(The invention relates to an open-loop starting strategy based on a power angle self-balancing characteristic, wherein a speed loop and a current loop are in an open-loop condition, and d-axis voltage ， To align the desired voltage, the q-axis voltage Angle of desired position (iv) DEG; applying a voltage vector in a direction 90 degrees different from the expected position angle, and rotating the rotor to the expected position angle; removing the expected voltage of the d axis, and entering an open loop starting stage; the speed loop is in an open loop, the current loop is in a closed loop condition, and the d-axis expected current Applying q-axis current Up to the desired maximum current Desired acceleration Angular velocity Angle of rotation (ii) a q axis current Is maintained at the desired maximum current When the angular velocity is greater than the minimum observed velocity When the observer is started, the observer is started; q axis current From the desired maximum current And reducing, comparing the angle and the angular speed observed by the observer with the expected angle and the angular speed, meeting the switching threshold value, and carrying out closed-loop switching. The open-loop starting strategy of the invention solves the defects of poor applicability, torque pulsation during starting and switching and the like of the existing motor under the low-speed condition.)

1. An open loop starting strategy based on a power angle self-balancing characteristic is characterized in that: comprises the following steps of (a) carrying out,

step 1, the speed loop and the current loop are in an open loop condition, and d-axis voltage

Step 2, the speed loop and the current loop are in an open loop condition, and d-axis voltageWherein

step 3, removing the expected voltage of the d axis, and starting to enter an open loop starting stage;

step 4, the speed ring is in an open loop, the current ring is in a closed loop condition, and the d-axis expected current

Step 5, the speed ring is in an open loop, the current ring is in a closed loop condition, and the d-axis expected current

step 6, the speed ring is in an open loop, the current ring is in a closed loop condition, and the d-axis expected currentQ-axis current

Technical Field

The invention relates to the technical field of permanent magnet synchronous motor speed sensorless control, in particular to an open loop starting strategy based on a power angle self-balancing characteristic.

Background

The permanent magnet motor has the characteristics of high efficiency, high power density, good control performance and low maintenance cost, so the permanent magnet motor has wide application range, is used in various fields of aerospace, national defense, industry and agriculture, production, daily life and the like, and gradually becomes the main force of the application of a motor driving system, particularly a precise servo and an electric vehicle.

In the motor control strategy, in order to obtain real-time and accurate position information, a position detection device such as a hall position sensor, a resolver, or a photoelectric encoder is generally required to be installed. These sensors usually have high accuracy and response speed, but at the same time, the cost, size, weight and inertia of the system are increased, the complexity of design, wiring and installation is increased, the problem of electromagnetic compatibility is caused, and the reliability of the system is reduced, so that the application occasions are limited. In order to avoid the above problems, a position sensorless control technology has appeared, and for a sensorless control strategy, most of them adopt a back electromotive force observation algorithm, but when a motor is in a low speed condition, the back electromotive force is small, the back electromotive force observation algorithm is limited, and it is an I/F control strategy that is used mostly, and based on the algorithm, two control methods are generally adopted:

the first is that the speed loop is in open loop condition, the current loop is in closed loop condition, and the d-axis expected current

Q-axis desired currentDesired acceleration

Then angular velocity

Angle of rotationWherein

Which represents the slope of the current and,the time of action is expressed as a function of time,representing the acceleration constant. The current slope and the acceleration constant are calibrated according to the characteristics of the load and the motor in actual use, the applicability of the same parameter is poor under different load conditions, and the motor shakes seriously at the moment of starting, so that the starting fails under the serious condition.

The second is that the speed loop is in open loop condition, the current loop is in closed loop condition, and the d-axis expected current

Q-axis desired currentDesired acceleration

Then angular velocityAngle of rotationWherein

Representing the current constant. The current constant and the acceleration constant are calibrated according to the load and the motor characteristics in actual use, compared with the first mode, the method has the advantages that the motor is relatively smooth in starting, but after closed-loop switching, the expected current of a d axis is required

Q-axis desired current

Wherein

The desired current is obtained for the speed closed loop, and the current is suddenly changed, so that torque pulsation is caused, and the system performance is seriously influenced.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects of poor applicability, torque pulsation during starting and switching and the like of a motor under a low-speed condition in the prior art, the invention provides an open-loop starting strategy based on a power angle self-balancing characteristic, so that the torque pulsation is greatly reduced, and the system robustness is improved.

The technical scheme of the invention is as follows: an open loop starting strategy based on power angle self-balancing characteristics comprises the following steps,

step 1, the speed loop and the current loop are in an open loop condition, and d-axis voltageWhereinTo align the desired voltage, the q-axis voltageAngle of desired position°；

Step 2, mixing the raw materialsDegree ring, current ring in open-loop condition, d-axis voltage

WhereinTo align the desired voltage, the q-axis voltage

Applying a voltage vector oriented 90 ° from the desired position angle to which the rotor is rotatable;

step 3, removing the expected voltage of the d axis, and starting to enter an open loop starting stage;

step 4, the speed ring is in an open loop, the current ring is in a closed loop condition, and the d-axis expected current

Applying q-axis currentIncrease to the desired maximum current

Desired acceleration

Angular velocityAngle of rotation

；

Step 5, the speed ring is in an open loop, the current ring is in a closed loop condition, and the d-axis expected current

Q-axis current

Is maintained at the desired maximum currentDesired accelerationAngular velocity

Angle of rotationWhen the angular velocity is greater than the minimum observed velocityWhen the observer is started, the observer is used for observing angular speed and angle;

step 6, the speed ring is in an open loop, the current ring is in a closed loop condition, and the d-axis expected currentQ-axis currentFrom the desired maximum current

Reduction of the desired accelerationAngular velocityAnd comparing the angle and the angular speed observed by the observer with the expected angle and the angular speed, and performing closed-loop switching when the error value is smaller than a switching error threshold value.

The technical scheme of the invention has the following remarkable effects:

(1) when the expected position angle is 0 degree, the initial angle of the FOC control rotor is-90 degrees, a current vector which is equivalent to a q axis is applied to a real d axis, so that the torque is slowly increased along with the increase of the FOC control angle, the d axis rotates to be coincided with the q axis, the angle of the rotor is 0 degree, and the problem that the motor shakes at the moment of starting can be avoided.

(2) Because the open loop uses the q-axis current vector, the q-axis current vector is still continuously used after the closed loop, and the d-axis is completely unchanged, according to the principle of power angle self-balancing, when the current is gradually reduced and the acceleration is unchanged, the error angle is gradually reduced, and when the error angle is 0, the smooth switching of the closed loop is carried out, so that the sudden change of the current during the switching is avoided to a great extent, and the sudden change of the rotating speed is reduced.

(3) Has higher applicability under different load conditions.

Drawings

FIG. 1 is a block diagram of a motor control system in an embodiment of the present invention.

Fig. 2 is a schematic diagram of current and angular velocity in a specific embodiment of the invention.

FIG. 3 is a waveform of the speed at idle condition for an exemplary embodiment.

Fig. 4 is a waveform of the angle under no-load conditions in this embodiment.

FIG. 5 is a graph of speed and angle error and q-axis current waveform under no-load conditions for an exemplary embodiment.

Fig. 6 is a waveform diagram of the rotation speed under the condition of the load torque 1NM in the embodiment.

FIG. 7 is a waveform diagram of an angle under the condition of the load torque 1NM in the embodiment.

FIG. 8 is a graph of the speed and angle error and the q-axis current waveform for the load torque 1NM condition in the example embodiment.

Fig. 9 is a waveform diagram of the rotation speed under the condition of the load torque 2NM in the embodiment.

Fig. 10 is an angle waveform diagram under the load torque 2NM condition in the specific embodiment.

FIG. 11 is a graph of the speed and angle error and the q-axis current waveform for the load torque 2NM condition in the example embodiment.

Detailed Description

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

The invention relates to an open loop starting strategy based on a power angle self-balancing characteristic, which comprises the following steps of 1, enabling a speed loop and a current loop to be in an open loop condition, and enabling d-axis voltageWhereinTo align the desired voltage, the q-axis voltage

Angle of desired position

(ii) a Step 2, the speed loop and the current loop are in an open loop condition, and d-axis voltageWherein

To align the desired voltage, the q-axis voltageApplying a voltage vector in a direction 90 ° different from the desired position angle with the FOC, the rotor being rotatable to the desired position angle; step 3, removing the expected voltage of the d axis and entering an open loop starting stage; step 4, the speed ring is in an open loop, the current ring is in a closed loop condition, and the d-axis expected currentApplying q-axis currentIncrease to the desired maximum current

Desired acceleration

Angular velocityAngle of rotation(ii) a Step 5, the speed ring is in an open loop, the current ring is in a closed loop condition, and the d-axis expected currentQ-axis currentIs maintained at the desired maximum currentDesired acceleration

Angular velocityAngle of rotationWhen the angular velocity is greater than the minimum observed velocityWhen the observer is started, the observer is used for observing angular speed and angle;

step 6, the speed ring is in an open loop, the current ring is in a closed loop condition, and the d-axis expected current

Q-axis current

From the desired maximum currentReduction of the desired accelerationAngular velocityAnd comparing the angle and the angular speed observed by the observer with the expected angle and the angular speed, and performing closed-loop switching when the error value is smaller than a switching error threshold value.

Specifically, the q-axis desired maximum current, the desired current profile, and the desired acceleration need to be calibrated at full circuit load conditions.

Specifically, a current inner loop regulator is arranged to regulate the actual current of the q axis, and fig. 2 is a current change curve of the expected current of the q axis.

In order to verify the validity of the strategy, the strategy is used in the motor control system block diagram of fig. 1, and simulation analysis is performed.

The strategy is used for verifying the system under the conditions of no load, load torque 1NM and load torque 2 NM.

Simulation analysis experiment 1, analysis of influence of strategy on system under no-load condition

Fig. 3 shows waveforms of the given rotation speed, the actual rotation speed of the motor and the estimated rotation speed of the observer when the system is under the no-load condition, and it can be seen that the observed speed is obviously inaccurate during the low speed period, and the estimation effect is good after the rotation speed is increased; in addition, at the moment of starting the motor, the motor does not generate overlarge transient torque, but slowly increases the speed along with the increase of the expected speed; after 0.1s, the three speeds are basically consistent, and the fluctuation of the rotating speed of the motor is small in the acceleration process.

Fig. 4 shows waveforms of a given angle, an actual angle of a motor and an estimated angle of an observer when a system is in an unloaded condition, when the motor is started, the given angle lags behind a real angle by 90 °, that is, an initial error angle is 90 °, a torque gradually increases and the error angle gradually decreases with a gradual increase of a given speed, in order to enable the error angle to be close to 0 quickly, a q-axis current is gradually decreased, in order to maintain the same torque, the error angle is gradually decreased until the error angle is 0 according to a power angle self-balancing characteristic, then the given angle leads the real angle, the torque is decreased, and the actual speed is dropped.

Fig. 5 shows the angle and speed error and the current curve of the system under no-load condition, and it can be seen that when the position error is close to 0, the current is about 0.2A, and the rotational speed error is-60 RPM, so that after switching to the closed loop, the current does not produce a large sudden change, and the system operates more smoothly.

Simulation analysis experiment 2, analysis of influence of strategy on system under load 1NM

Fig. 6, 7, and 8 are waveform diagrams under the load 1NM condition, respectively, and it can be seen from fig. 8 that when the position error is close to 0, the current is about 1.1A, and the rotational speed error is-30 RPM.

Simulation analysis experiment 3, analysis of influence of strategy on system under load 2NM

Fig. 9, 10, and 11 are waveform diagrams under the condition of load 2NM, respectively, and it can be seen from fig. 11 that when the position error is close to 0, the current is about 2.2A, and the rotation speed error is-25 RPM.

Therefore, comparing the currents in the no-load, 1NM and 2NM switching states, the strategy automatically adjusts the magnitude of the expected current according to the load characteristics, and can realize smooth transition in the closed-loop switching state.