CN103414427A

CN103414427A - Brushless direct current motor control method

Info

Publication number: CN103414427A
Application number: CN2013103496998A
Authority: CN
Inventors: 李宁; 汪木兰; 左健民
Original assignee: Nanjing Institute of Technology
Current assignee: Huai'an Qingjiangpu District Market Supervision Comprehensive Service Center
Priority date: 2013-08-12
Filing date: 2013-08-12
Publication date: 2013-11-27
Anticipated expiration: 2033-08-12
Also published as: CN103414427B

Abstract

The present invention provides a brushless DC motor control method, which only uses a simple switch-type Hall position detector and an observer realized by software to reconstruct relatively accurate observation values of motor rotation angle and motor speed. The observed value realizes the sine wave vector control of the brushless DC motor. This method not only retains the simple, reliable and low-cost advantages of the brushless motor control system, but also improves the control accuracy and dynamic performance.

Description

Brushless DC Motor Control Method

技术领域technical field

本发明涉及一种无刷直流电动机的控制方法，特别涉及一种基于观测器的无刷直流电动机正弦波矢量控制方法。The invention relates to a control method of a brushless direct current motor, in particular to an observer-based sine wave vector control method of a brushless direct current motor.

背景技术Background technique

根据相励磁磁势分布的不同，三相永磁同步电动机可分为两种类型：正弦波型和方波型永磁同步电动机，前者励磁磁势分布是正弦波状，后者励磁磁势分布呈方波状。According to the different phase excitation magnetic potential distribution, three-phase permanent magnet synchronous motors can be divided into two types: sinusoidal and square wave permanent magnet synchronous motors, the former excitation magnetic potential distribution is sinusoidal, and the latter excitation magnetic potential distribution is Square wave shape.

方波型永磁同步电动机亦称为无刷直流电动机（BLDC）；正弦波型永磁同步电动机习惯被称为PMSM（Permanent Magnet Synchronous Motor）。按照传统的技术，正弦波永磁同步电机（PMSM），一般采用正弦波矢量控制方式，用于高精度的位置伺服控制，需要比较高精度的位置检测器，如光电脉冲编码器、旋转变压器等等。无刷直流电机（BLDC）一般采用方波控制方式，只用于简单的速度控制，仅仅装有简易的开关型霍尔位置检测器，其直接的位置检测精度仅有60度（电角度）。无刷直流电机控制系统的主要特点是简单可靠成本低，缺点是控制精度和动态性能较低。Square wave permanent magnet synchronous motor is also called brushless DC motor (BLDC); sine wave permanent magnet synchronous motor is customarily called PMSM (Permanent Magnet Synchronous Motor). According to the traditional technology, the sine wave permanent magnet synchronous motor (PMSM) generally adopts the sine wave vector control method for high-precision position servo control, and requires relatively high-precision position detectors, such as photoelectric pulse encoders, resolvers, etc. wait. Brushless DC motors (BLDC) generally adopt a square wave control method, which is only used for simple speed control. It is only equipped with a simple switch-type Hall position detector, and its direct position detection accuracy is only 60 degrees (electrical angle). The main feature of the brushless DC motor control system is simplicity, reliability and low cost. The disadvantage is that the control accuracy and dynamic performance are low.

近年来无刷直流电机正弦波矢量控制方法一直处于研究中，需要解决的最主要问题是在只采用简单霍尔检测器的情况下，尽量提高位置检测精度，通常的解决方法是：假定前一个霍尔信号周期与当前的霍尔信号周期相同，通过测量时间，间接地计算电机转角,这种方法在速度较低和电机处于速度变化状态下是不准确的，因而也限制了其实用性。In recent years, the sine wave vector control method of brushless DC motors has been under research. The main problem to be solved is to improve the position detection accuracy as far as possible when only using a simple Hall detector. The usual solution is: Assume that the previous The Hall signal period is the same as the current Hall signal period. By measuring the time, the motor rotation angle is calculated indirectly. This method is inaccurate when the speed is low and the motor is in a state of speed change, thus limiting its practicability.

发明内容Contents of the invention

本发明所要解决的技术问题：本发明为了解决现有技术中存在缺陷，无刷直流电机的转角、速度和负载观测模型及其控制方法，该方法仅利用简易的开关型霍尔位置检测器，实现无刷直流电机的正弦波控制。The technical problem to be solved by the present invention: in order to solve the defects in the prior art, the present invention has the rotation angle, speed and load observation model and its control method of the brushless DC motor. The method only utilizes a simple switch-type Hall position detector, Realize the sine wave control of brushless DC motor.

本发明的技术方案是：Technical scheme of the present invention is:

无刷直流电机控制方法，包括以下步骤：A method for controlling a brushless DC motor, comprising the following steps:

步骤1，建立无刷直流电机的转角、速度和负载观测模型，具体如下：Step 1, establish the rotation angle, speed and load observation model of the brushless DC motor, as follows:

（1）以固定的检测周期T，实时读取电机霍尔检测器发出的三路位置脉冲信号,实时计取三路位置脉冲总个数，通过下式得到电机转角的计算值

和速度的计算值

(1) With a fixed detection period T, read the three-way position pulse signal sent by the motor Hall detector in real time, count the total number of three-way position pulses in real time, and obtain the calculated value of the motor rotation angle by the following formula

and speed calculations

$\overset{~ ~}{θ θ} ((k k)) = = \frac{22 πP πP}{33} N N ((k k))$

$\overset{~ ~}{ω ω} ((k k)) = = \frac{22 πP πP}{33} ((N N ((k k)) - - N N ((k k - - 11)))) / / T T$

式中，k是循环采样次数，是电机转角的第k次计算值，

是电机速度的第k次计算值，N(k)是第k次检测得到的位置脉冲总个数，P是电机的磁极对数，T是检测周期；In the formula, k is the number of cyclic sampling, is the kth calculated value of the motor rotation angle,

is the kth calculated value of the motor speed, N(k) is the total number of position pulses detected by the kth time, P is the number of magnetic pole pairs of the motor, and T is the detection period;

（2）按下式进行低通滤波处理，得到电机的转角值θ和速度值ω；(2) Perform low-pass filter processing according to the following formula to obtain the motor's rotation angle value θ and speed value ω;

$θ θ ((k k)) = = α α \overset{~ ~}{θ θ} ((k k)) + + ((11 - - α α)) θ θ ((k k - - 11))$

$ω ω ((k k)) = = α α \overset{~ ~}{ω ω} ((k k)) + + ((11 - - α α)) ω ω ((k k - - 11))$

式中，θ(k)是电机转角的第k次滤波输出值，ω(k)是电机速度的第k次滤波输出值，α是滤波器系数，介于0和1之间；In the formula, θ(k) is the k-th filter output value of the motor rotation angle, ω(k) is the k-th filter output value of the motor speed, and α is the filter coefficient, which is between 0 and 1;

（3）依据电机的动力学特性，构建电机转角和速度观测模型如下：(3) According to the dynamic characteristics of the motor, the motor angle and speed observation model is constructed as follows:

$\overset{^^}{θ θ} ((k k)) = = \overset{^^}{θ θ} ((k k - - 11)) + + \overset{^^}{ω ω} ((k k - - 11)) * * T T$

$\overset{^^}{ω ω} ((k k)) = = \frac{11}{J J} (({K K}_{m m} {i i}_{q q} ((k k)) - - {T T}_{fz fz} ((k k)))) * * T T + + \overset{^^}{ω ω} ((k k - - 11))$

式中，

瞬时转角观测值，为瞬时速度观测值，J是电机的转动惯量，K_m是转矩系数，i_q是电机定子电流的交轴分量，采用定子电流交轴分量的指令值

代替实际的i_q，T_fz是负载转矩；通过负载观测模型计算得出，所述负载观测模型如下：In the formula,

Instantaneous rotation angle observations, is the instantaneous speed observation value, J is the moment of inertia of the motor, K _m is the torque coefficient, i _q is the quadrature axis component of the motor stator current, and the command value of the quadrature axis component of the stator current is used

Instead of the actual i _q , T _fz is the load torque; calculated by the load observation model as follows:

${T T}_{fz fz} ((k k)) = = {a a}_{11} ((θ θ ((k k)) - - \overset{^^}{θ θ} ((k k)))) + + {a a}_{22} ((ω ω ((k k)) - - \overset{^^}{ω ω} ((k k))))$

式中，a₁和a₂是负载观测器系数，可离线计算得到；In the formula, a ₁ and a ₂ are load observer coefficients, which can be calculated offline;

步骤2，将步骤1建立的电机转角和速度观测模型以及负载观测模型整合，得到转角、转速观测器，用于实时得到转角观测值

和速度观测值

将其应用于控制方法如下：Step 2, integrate the motor angle and speed observation model established in step 1, and the load observation model to obtain the angle and speed observer, which is used to obtain the observed value of the rotation angle in real time

and velocity observations

Apply it to the control method as follows:

以转角观测值为位置反馈信号，将位置给定信号θ^*与位置反馈信号相减而得到位置跟随误差信号，位置跟随误差信号经位置控制器后输出速度给定信号ω^*；Observation by rotation angle For the position feedback signal, combine the position given signal θ ^* with the position feedback signal The position following error signal is obtained by subtraction, and the position following error signal outputs the speed given signal ω ^* after passing through the position controller;

以速度观测值

为速度反馈信号，将速度给定信号ω^*与速度反馈信号

相减而得速度误差信号，速度误差信号经速度控制器后输出q轴电流给定信号

Take speed observations

As the speed feedback signal, combine the speed given signal ω ^* with the speed feedback signal

The speed error signal is obtained by subtraction, and the speed error signal outputs the q-axis current given signal after passing through the speed controller

检测电机定子电流i_a、i_b，经过旋转变换器形成交轴电流i_q和直轴电流i_d；以转角观测值作为旋转变换器的旋转变换角度，将q轴电流给定信号

与交轴电流i_q相减而得q轴电流误差信号，此误差信号经q轴电流控制器后输出交轴电压u_q，d轴电流给定信号为0，将直轴电流i_d经d轴电流控制器后输出直轴电压u_d，Detect the motor stator current i _a , i _b , form the quadrature axis current i _q and the direct axis current i _d through the rotary converter; take the observed value of the rotation angle as the rotation conversion angle of the rotary converter, and give the q-axis current signal

The q-axis current error signal is obtained by subtracting the quadrature-axis current i _q , the error signal outputs the quadrature-axis voltage u _q after passing through the q-axis current controller, the given signal of the d-axis current is 0, and the direct-axis current i _d is passed through d After the axis current controller outputs the direct axis voltage u _d ,

所述交轴电压u_q和直轴电压u_d经逆旋转变换器形成电机定子三相交流电压参考信号u_a、u_b、u_c，再经SPWM调制，用于控制主回路中的逆变器，驱动电机。The quadrature-axis voltage u _q and the direct-axis voltage u _d pass through the inverse rotary converter to form three-phase AC voltage reference signals u _a , u _b , _uc of the motor stator, and then modulated by SPWM to control the inverter in the main circuit to drive the motor.

所述步骤2中的滤波器的系数α应当随着速度的变化进行调整，电机速度越低，α值应当越小，速度越高，α值应当越大；所述滤波器的系数α小于等于0.9且大于等于0.1。The coefficient α of the filter in the step 2 should be adjusted as the speed changes, the lower the motor speed, the smaller the value of α, and the higher the speed, the greater the value of α; the coefficient α of the filter is less than or equal to 0.9 and greater than or equal to 0.1.

技术效果technical effect

本发明给出了一种无刷直流电动机的正弦波矢量控制方法，它仅利用简易的开关型霍尔位置检测器，通过软件实现的观测器，重构出比较精确的电机转角和电机速度的观测值，利用观测值实现无刷直流电动机的正弦波矢量控制。这种方法既保留了无刷电机控制系统简单可靠成本低的优点，同时提高了控制精度和动态性能。The present invention provides a sine wave vector control method for a brushless DC motor, which uses only a simple switch-type Hall position detector and an observer realized by software to reconstruct a relatively accurate motor rotation angle and motor speed. Observed value, using the observed value to realize the sine wave vector control of the brushless DC motor. This method not only retains the simple, reliable and low-cost advantages of the brushless motor control system, but also improves the control accuracy and dynamic performance.

附图说明Description of drawings

图1是转角、转速观测器的结构框图；Fig. 1 is a structural block diagram of the rotation angle and rotational speed observer;

图2是基于转角、转速观测器的无刷直流电机控制系统的结构框图；Figure 2 is a structural block diagram of a brushless DC motor control system based on a rotation angle and speed observer;

图3是无刷直流电机控制系统的电路原理图；Fig. 3 is a circuit schematic diagram of a brushless DC motor control system;

图4是无刷直流电机控制系统软件主程序流程图；Fig. 4 is a flow chart of the main program of the brushless DC motor control system software;

图5是无刷直流电机控制系统软件中断服务程序流程图。Fig. 5 is a flow chart of the software interrupt service program of the brushless DC motor control system.

具体实施例specific embodiment

一种无刷直流电机转角和速度观测模型及负载观测模型构建方法如下：A brushless DC motor angle and speed observation model and load observation model construction method is as follows:

（1）以固定的检测周期T，实时读取电机霍尔检测器发出的三路位置脉冲信号,实时计取三路位置脉冲总个数。通过下式得到电机转角的计算值

和速度的计算值 (1) With a fixed detection cycle T, read the three-way position pulse signals sent by the motor Hall detector in real time, and count the total number of three-way position pulses in real time. The calculated value of the motor rotation angle is obtained by the following formula

and speed calculations

$\overset{~ ~}{θ θ} ((k k)) = = \frac{22 πP πP}{33} N N ((k k))$

式中，k是循环采样次数，

是电机转角的第k次计算值，

是电机速度的第k次计算值，N(k)是第k次检测得到的位置脉冲个数，P是电机的磁极对数，T是检测周期。In the formula, k is the number of cyclic sampling,

is the kth calculated value of the motor rotation angle,

is the kth calculated value of the motor speed, N(k) is the number of position pulses detected by the kth time, P is the number of magnetic pole pairs of the motor, and T is the detection cycle.

（2）由于电机的霍尔检测器精度低，电机转角计算值和速度计算值都是的阶梯信号，是不连续的，须按下式进行低通滤波处理，得到电机的转角值θ和速度值ω。(2) Due to the low precision of the Hall detector of the motor, the calculated value of the motor rotation angle and the calculated value of the speed are both step signals, which are discontinuous. It is necessary to perform low-pass filtering according to the following formula to obtain the motor rotation angle value θ and speed value ω.

式中，θ(k)是电机转角的第k次滤波输出值，ω(k)是电机速度的第k次滤波输出值。α是滤波器系数，理论上介于0和1之间。In the formula, θ(k) is the k-th filter output value of the motor rotation angle, and ω(k) is the k-th filter output value of the motor speed. α is the filter coefficient, theoretically between 0 and 1.

（3）滤波器的系数α应当随着速度的变化进行调整，电机速度越低，α值应当越小，速度越高，α值应当越大，实际经验表明，α小于等于0.9且大于等于0.1。(3) The coefficient α of the filter should be adjusted as the speed changes. The lower the motor speed, the smaller the α value, and the higher the speed, the larger the α value. Practical experience shows that α is less than or equal to 0.9 and greater than or equal to 0.1 .

（4）按上述步骤得到电机的转角值θ和速度值ω，仍然存在较大的波动，而且存在时间上的滞后，为了得到瞬时转角观测值

和瞬时速度观测值

应当依据电机的动力学特性，构建“电机转角和速度观测模型”如下：(4) According to the above steps to obtain the motor's rotation angle value θ and speed value ω, there are still large fluctuations, and there is a time lag, in order to obtain the instantaneous rotation angle observation value

and instantaneous velocity observations

According to the dynamic characteristics of the motor, the "motor rotation angle and speed observation model" should be constructed as follows:

式中，J是电机的转动惯量，K_m是转矩系数，i_q是电机定子电流的交轴分量，T_fz是负载转矩。In the formula, J is the moment of inertia of the motor, K _m is the torque coefficient, i _q is the quadrature axis component of the motor stator current, and T _fz is the load torque.

（5）在重构的观测模型中，为了实际运算的方便，可用定子电流交轴分量的指令值代替实际的i_q。(5) In the reconstructed observation model, for the convenience of actual calculation, the command value of the quadrature axis component of the stator current can be used in place of the actual i _q .

（6）在重构的观测模型中，负载转矩T_fz可根据前面得到的θ与

的差，ω与

的差，按下式计算得到，该式称为“负载观测模型”。(6) In the reconstructed observation model, the load torque T _fz can be obtained according to θ and

The difference between ω and

The difference is calculated according to the following formula, which is called "load observation model".

式中，a₁和a₂是负载观测器系数，可离线计算得到。In the formula, a ₁ and a ₂ are load observer coefficients, which can be calculated offline.

（7）将“电机转角和速度观测模型”以及“负载观测模型”整合，可得到“转角、转速观测器”，用于实时得到转角观测值

和速度观测值和

可用于电机的矢量运算和反馈控制。“转角、转速观测器”的结构见附图1。(7) Integrate the "Motor Angle and Speed Observation Model" and the "Load Observation Model" to obtain a "rotation angle and speed observer", which is used to obtain the observation value of the rotation angle in real time

and velocity observations and

It can be used for vector operation and feedback control of motors. The structure of "rotational angle and speed observer" is shown in Figure 1.

霍尔信号经计数、采样和预计算得到电机转角的计算值

和速度的计算值

电机转角的计算值

和速度计算值

经低通滤波器处理，得到电机的转角值θ和速度值ω，依据电机的动力学特性，构建“电机转角和速度观测模型”，同时构建“负载观测模型”，将“电机转角和转速观测模型”以及“负载观测模型”整合，可得到“转角、转速观测器”，实时获取转角观测值

和速度观测值

The hall signal is counted, sampled and pre-calculated to obtain the calculated value of the motor rotation angle

and speed calculations

Calculated value of the motor rotation angle

and speed calculations

After the low-pass filter processing, the motor's rotation angle value θ and speed value ω are obtained. According to the dynamic characteristics of the motor, the "motor rotation angle and speed observation model" is constructed, and the "load observation model" is constructed at the same time. The "motor rotation angle and speed observation model"Model" and "Load Observation Model" are integrated to obtain "rotation angle and speed observer" to obtain the observation value of rotation angle in real time

and velocity observations

(8)将“转角、转速观测器”用于无刷直流电机闭环控制系统中，可以实现正弦波矢量控制。基于“转角、转速观测器”的无刷直流电机控制系统的结构如附图2所示。(8) Using the "rotation angle and speed observer" in the closed-loop control system of the brushless DC motor can realize the sine wave vector control. The structure of the brushless DC motor control system based on the "rotation angle and speed observer" is shown in Figure 2.

以转角观测值为位置反馈信号,位置给定信号θ^*与位置反馈信号

相减而得到位置跟随误差，位置跟随误差经位置控制器，输出速度给定信号ω^*，以速度观测值

为速度反馈信号，速度给定信号ω^*与速度反馈信号

相减而得速度误差，速度误差经速度控制器，输出q轴电流给定信号检测电机定子电流i_a、i_b，经过旋转变换器形成交轴电流i_q和直轴电流i_d；旋转变换器的旋转变换角度是q轴电流给定信号

与交轴电流i_q相减而得q轴电流误差，此误差经q轴电流控制器，输出交轴电压u_q，d轴电流给定信号为0，直轴电流i_d经d轴电流控制器，输出直轴电压u_d，交轴电压u_q和直轴电压u_d，经逆旋转变换器形成电机定子三相交流电压参考信号u_a、u_b、u_c，再经SPWM调制，用于控制主回路中的逆变器，驱动电机。Observation by rotation angle is the position feedback signal, the position given signal θ ^* and the position feedback signal

The position following error is obtained by subtraction. The position following error passes through the position controller to output the speed given signal ω ^* , and the speed observation value

For the speed feedback signal, the speed given signal ω ^* and the speed feedback signal

The speed error is obtained by subtraction, the speed error is passed through the speed controller, and the q-axis current given signal is output Detect the motor stator current i _a , i _b , form the quadrature axis current i _q and the direct axis current i _d through the rotary converter; the rotation transformation angle of the rotary converter is q-axis current given signal

The q-axis current error is obtained by subtracting the quadrature-axis current i _q . This error is passed through the q-axis current controller to output the quadrature-axis voltage u _q , the given signal of the d-axis current is 0, and the direct-axis current _id is controlled by the d-axis current output direct-axis voltage u _d , quadrature-axis voltage u _q and direct-axis voltage u _d , through the inverse rotary converter to form three-phase AC voltage reference signals u _a , u _b , u _c of the motor stator, and then modulated by SPWM, using It is used to control the inverter in the main circuit and drive the motor.

在附图2所示的系统中，外环是位置环，位置给定信号是θ^*，位置反馈信号是

位置控制器的输出信号是速度给定信号ω^*，速度反馈信号是

速度控制器采用PI控制算法。In the system shown in Figure 2, the outer loop is a position loop, the position given signal is θ ^* , and the position feedback signal is

The output signal of the position controller is the given speed signal ω ^* , and the speed feedback signal is

The speed controller adopts PI control algorithm.

速度环的内部，包含了q轴电流环和d轴电流环，速度控制器的输出信号是q轴电流给定信号

d轴电流给定信号为0。检测电机定子电流i_a、i_b，经过旋转变换形成交轴电流i_q和直轴电流i_d,用于反馈。旋转变换角度是

来自“转角、转速观测器”。The interior of the speed loop includes the q-axis current loop and the d-axis current loop. The output signal of the speed controller is the q-axis current given signal

d-axis current given signal is 0. Detect the stator current _ia and _ib of the motor, and form quadrature axis current i _q and direct axis current _id through rotation transformation for feedback. The rotation transformation angle is

From "Angle, Speed Observer".

q轴电流控制器和d轴电流控制器均采用PI控制算法，其输出分别是交轴电压u_q和直轴电压u_d，经逆旋转变换可形成电机定子三相交流电压参考信号u_a、u_b、u_c，再经SPWM调制，用于控制主回路中的逆变器，驱动电机。Both the q-axis current controller and the d-axis current controller adopt PI control algorithm, and their outputs are respectively the quadrature axis voltage u _q and the direct axis voltage u _d , which can be transformed into three-phase AC voltage reference signals u _a , u _b , u _c , modulated by SPWM, are used to control the inverter in the main circuit and drive the motor.

（9）如图3所示，本系统的处理器是采用TMS320F28035,附图2中的转角、速度观测器、位置控制器、速度控制器、d轴电流控制器、q轴电流控制器、旋转变换、逆旋转变换等模块均由软件实现，SVPWM模块由TMS320F28035内部的硬件实现。采用两只电流传感器ACS712检测电机定子电流i_a、i_b，电流传感器的信号输入到TMS320F28035的A/D转换接口。(9) As shown in Figure 3, the processor of this system adopts TMS320F28035, the rotation angle, speed observer, position controller, speed controller, d-axis current controller, q-axis current controller, rotation Modules such as transformation and inverse rotation transformation are realized by software, and the SVPWM module is realized by hardware inside TMS320F28035. Two current sensors ACS712 are used to detect the motor stator current _ia , _ib , and the signal of the current sensor is input to the A/D conversion interface of TMS320F28035.

主回路为交—直—交结构，其中的逆变器由智能功率模块IRAMX20UP60A实现。The main circuit is AC-DC-AC structure, and the inverter is realized by intelligent power module IRAMX20UP60A.

如图4和图5所示，分别为无刷直流电机控制软件主流程图和无刷直流电机控制系统软件中断服务程序流程图。所述的无刷直流电机控制软件主流程如下：1）初始化系统时钟、中断向量表、IO端口，2）初始化控制参数表，3）初始化A/D转换电路、PWM输出，4）启动控制周期定时器，5）等待控制周期定时器中断、刷新人机界面，6）读取霍尔传感器信号Ha、Hb、Hc，计算电机转角

和转速

，7）计算电机转角滤波值θ(k)和转速滤波值ω(k)，8）计算转角观测值

和速度观测值

，9）根据电流i_a、i_b、i_c的当前值，计算i_q(k)和i_d(k)；分别以主循环周期的1倍、2倍、4倍控制周期，完成位置控制器、速度控制器、电流控制器的刷新运算；10）根据交、直轴电流控制器的输出信号u_q(k)和u_d(k)，以及转角观测值

，通过逆旋转变换，计算三相电子电压的参考值，刷新SVPWM环节。无刷直流电机控制系统软件中断服务程序如下：1）响应定时中断，2）启动A/D转换器，3）读取A相电流采样值，4）读取B相电流采样值，5）读取C相电流采样值，6）中断返回。As shown in Figure 4 and Figure 5, they are the main flow chart of the brushless DC motor control software and the flow chart of the interrupt service routine of the brushless DC motor control system software. The main flow of the brushless DC motor control software is as follows: 1) Initialize the system clock, interrupt vector table, IO port, 2) Initialize the control parameter table, 3) Initialize the A/D conversion circuit, PWM output, 4) Start the control cycle Timer, 5) Wait for the control cycle timer interrupt, refresh the man-machine interface, 6) Read the Hall sensor signals Ha, Hb, Hc, and calculate the motor rotation angle

and speed

, 7) Calculate the motor rotation angle filter value θ(k) and speed filter value ω(k), 8) Calculate the rotation angle observation value

and velocity observations

, 9) Calculate i _q (k) and i _d (k) according to the current values of current i _a , i _b , and i _c ; complete position control with 1, 2, and 4 times the control period of the main cycle respectively 10) According to the output signals u _q (k) and u _d (k) of the AC and D axis current controllers, and the observed value of the rotation angle

, calculate the reference value of the three-phase electronic voltage through inverse rotation transformation, and refresh the SVPWM link. The software interrupt service program of the brushless DC motor control system is as follows: 1) Respond to the timing interrupt, 2) Start the A/D converter, 3) Read the sampled value of the A-phase current, 4) Read the sampled value of the B-phase current, 5) Read Take the current sampling value of phase C, 6) return from interrupt.

Claims

1. The brushless DC motor control method is characterized in that: comprising the following steps:

Step 1, establish the rotation angle, speed and load observation model of the brushless DC motor, as follows:

and speed calculations

\overset{~ ~}{θ θ} ((k k)) = = \frac{22 πP πP}{33} N N ((k k))

\overset{~ ~}{ω ω} ((k k)) = = \frac{22 πP πP}{33} ((N N ((k k)) - - N N ((k k - - 11)))) / / T T

In the formula, k is the number of cyclic sampling,

is the kth calculated value of the motor rotation angle,

(2) Perform low-pass filter processing according to the following formula to obtain the motor's rotation angle value θ and speed value ω;

θ θ ((k k)) = = α α \overset{~ ~}{θ θ} ((k k)) + + ((11 - - α α)) θ θ ((k k - - 11))

ω ω ((k k)) = = α α \overset{~ ~}{ω ω} ((k k)) + + ((11 - - α α)) ω ω ((k k - - 11))

In the formula, θ(k) is the k-th filter output value of the motor rotation angle, ω(k) is the k-th filter output value of the motor speed, and α is the filter coefficient, which is between 0 and 1;

(3) According to the dynamic characteristics of the motor, the observation model of the motor rotation angle and speed is constructed as follows:

\overset{^^}{θ θ} ((k k)) = = \overset{^^}{θ θ} ((k k - - 11)) + + \overset{^^}{ω ω} ((k k - - 11)) * * T T

\overset{^^}{ω ω} ((k k)) = = \frac{11}{J J} (({K K}_{m m} {i i}_{q q} ((k k)) - - {T T}_{fz fz} ((k k)))) * * T T + + \overset{^^}{ω ω} ((k k - - 11))

In the formula,

Instantaneous rotation angle observations,

is the instantaneous speed observation value, J is the moment of inertia of the motor, K _m is the torque coefficient, i _q is the quadrature axis component of the motor stator current, and the command value of the quadrature axis component of the stator current is used

{T T}_{fz fz} ((k k)) = = {a a}_{11} ((θ θ ((k k)) - - \overset{^^}{θ θ} ((k k)))) + + {a a}_{22} ((ω ω ((k k)) - - \overset{^^}{ω ω} ((k k))))

In the formula, a ₁ and a ₂ are load observer coefficients, which can be calculated offline;

Step 2, integrate the motor angle and speed observation model established in step 1, and the load observation model to obtain the angle and speed observer, which is used to obtain the observed value of the rotation angle in real time

and velocity observations

; apply it to the control method as follows:

Observation by rotation angle

For the position feedback signal, combine the position given signal θ ^* with the position feedback signal The position following error signal is obtained by subtraction, and the position following error signal outputs the speed given signal ω ^* after passing through the position controller;

Take speed observations

;

Detect the motor stator current i _a , i _b , form the quadrature axis current i _q and the direct axis current i _d through the rotary converter; take the observed value of the rotation angle as the rotation conversion angle of the rotary converter, and give the q-axis current signal

The quadrature-axis voltage u _q and the direct-axis voltage u _d pass through the inverse rotary converter to form three-phase AC voltage reference signals u _a , u _b , _uc of the motor stator, and then modulated by SPWM to control the inverter in the main circuit to drive the motor.

2. The brushless DC motor control method according to claim 1, characterized in that: the coefficient α of the filter in the step 2 should be adjusted as the speed changes, the lower the motor speed, the smaller the value of α , the higher the speed, the greater the value of α; the coefficient α of the filter is less than or equal to 0.9 and greater than or equal to 0.1.