【作者】 苏健勇；

【导师】 李铁才；

【作者基本信息】 哈尔滨工业大学 ， 电机与电器， 2009， 博士

【摘要】 永磁同步电动机(PMSM)具有体积小、效率高、可靠性高以及对环境适应性强等诸多优点,在各种高性能驱动系统中得到了广泛应用。永磁同步电动机无传感器控制技术不但能够降低系统成本,而且能够增加系统可靠性,是当前电机控制技术领域的研究热点之一。无传感器控制技术的研究在高速电机、微型电机、航空航天、水下机器人、家用电器等一些特殊场合具有重要意义。本文以永磁同步电动机扩展状态滑模观测器为研究重点,对磁链观测技术、参数误差影响、高阶滑模控制、位置和速度估算及观测器实现方法等进行了深入研究,并进行相应的仿真和实验分析。传统滑模观测器是建立在以电流为状态变量的二阶状态方程基础上,进行PMSM反电势观测,此时滑模控制率由符号函数组成,在数字实现时存在严重抖振现象,观测结果无法直接使用。使用低通滤波器会引起观测值幅值和相位发生变化,无法忽略并难以进行精确补偿。本文在分析表贴式永磁同步电动机电压方程和磁链变化规律基础上,建立以电流和磁链为状态变量的四阶扩展状态方程,提出扩展状态滑模观测器。在观测器电流方程部分,以电流偏差建立滑模面,采用滑模面的符号函数构成滑模控制率作为输入,并利用Lyapunov定理证明广义滑模可达性,进一步得出滑模增益矩阵自适应率。在观测器磁链方程部分,将滑模控制率乘以反馈矩阵作为输入,当滑模运动发生后,磁链误差渐近收敛到零。该观测器的特点是,滑模控制率中抖振可以被磁链方程滤波而不影响观测值,因此可使用磁链观测值直接进行转子位置和速度计算,避免了额外采用低通滤波器所带来的相位变化。同时观测器引入了转子角速度作为参数,该参数是时变的且在动态过程中将会存在一定误差。根据此误差存在时磁链观测应相互解耦原则进行选择反馈矩阵,可保证观测器中转速参数存在误差时也可以正确地计算出转子速度。由于内嵌式永磁同步电动机在静止坐标系下的电压方程中电感系数是时变的,无法直接应用上述观测器。本文通过对旋转坐标下电压方程做适当变换,推导出静止坐标系下含有时不变参数的状态方程。通过定义等效磁链,可以将基于静止坐标系下的观测器技术应用在内嵌式永磁同步电动机中进行转子角度和速度的估算,并近一步利用Lyapunov定理推导出参数取值方法。由于测量方法或工作状态的变化,观测器中参数将会存在一定误差。本文着重分析角速度误差存在时磁链观测结果变化规律,推导出幅值和相位变化与转速误差大小和观测器反馈矩阵的关系。对于定子电阻和电感误差,通过分析得到磁链观测误差与与电流相位关系,结合交流电机矢量控制理论中电流和磁链的相位关系,推导出磁链观测值实际值之间的相位关系,即转子角度估算值与实际值之差。磁链观测的目的是计算出转子角度和速度,本文采用一种基于锁相环的方法计算磁链周期和相位,从而得到转子角度和速度,该方法具有动态响应快和低通滤波等特点,可减小磁链观测值扰动影响。转子速度估算动态响应与观测器和锁相环有关,进一步分析了观测器和锁相环参数对角速度估算暂态影响。对于电机在零速时起动问题,采用虚拟位置和电流闭环控制相结合的起动策略,并说明了速度闭环切换方法。为进一步提高转速闭环动态响应,本文在传统滑模面基础上引入非线性滑模面,并选取适当控制率,构成二阶非奇异终端滑模观测器。控制率含有开关函数的积分形式,与原有直接含有开关函数相比抖振现象大大减小,并利用Lyapunov定理证明了观测器的稳定性,推导出参数取值方法。由于抖振的减小,可增加观测器带宽,从而提高速度闭环动态响应。对无传感器永磁同步电机数字控制系统硬件和软件进行设计。以该控制系统为基础,给出扩展状态滑模观测器的离散方法和实现结构,以及基于MATLAB的电机控制系统仿真结构图。重点介绍观测器算法在定点微处理器中实现方法,包括数据格式处理、方程实现以及控制规律中指数函数的处理办法。通过实验结果验证数字控制系统设计和观测器实现方法的有效性和可行性。更多还原

【Abstract】 Permanent magnet synchronous motor (PMSM) has been widely used in high performance drive applications for its advantages, such as compactness, high efficiency, reliability and suitability to environment. Sensorless control of PMSM has been a hot research topic of motor control technology, which has the advantages of low cost and high reliability. Sensorless control technology has a great significance in some special operation field, such as high speed motor, micro-motor, submarine robot and home appliances.This dissertation presents an extended state sliding mode observer of PMSM, and make deep research on flux observer, parameter error influence, high order sliding mode, position and speed calculation, observer digital implementation. And the corresponding simulations and experiments are carried on.The traditional sliding mode observer is based on the second order state equation, of which state variance is stator current, and is used to observe the back electromotive force. The equivalent control is composed of symbolic function. Much chattering exists in observed results. The low-pass filter will change the amplitude and phase of the observed results. The influence can’t be ignored and can’t be compensated accurately.The extended state sliding mode observer of SPMSM is based on the voltage equation and flux changing regularity. In the current part, the control input is composed of the symbolic function of the hyperplane. The general reachability is proved by Lyapunov theory. In the flux part, the product of sliding mode control and feedback matrix is adapted as the input control. When sliding mode occurs, the observed flux error will converge to zero. The merits are that the chatting can be filtered by flux equation. So the rotor position and speed can be calculated directly from observed flux without low pass filter. The feedback matrix is selected according to the rule, which is that the observed fluxes are decoupled when the speed error existed. Then the speed can be calculated correctly even if the error exists in the observer.In the IPMSM, the inductance is time-variant in voltage equation of the stationary coordinate. The observer can’t be utilized directly. The state equation with time invariant parameter is derived through the transform of voltage equation in rotating coordinate. The observer can be utilized by the definition of equivalent flux. The equivalence and hypothesis are proved to be appropriate by the analysis in the sensorless application field.According to the measure method or state varying, the parameters error in observer exist. The observed observation flux law is analysis when the angle speed error isn’t zero, and the relationship between the amplitude and phase and feedback parameter in observer is deduced. In the aspect of stator resistance and inductance error the relationship between observed and real flux are derived including amplitude and phase based on the current method in field oriented control. An improved PLL method is presented in order to calculate the rotor position and speed directly from observed flux, with the merits of fast response and low pass filter. The response of speed estimation between observer and PLL is analyzed. And startup strategy based on virtual position and current closed control and the method switch to speed closed loop are introduced.In order to improve the transient response, a second order NTSM observer is presented by the nonlinear sliding hyperplane which is the extension of the traditional linear hyperplane. The control of NTSM observer contains the integral of symbolic function, in which the chattering signal is much less than the one in traditional SMO. The stability of the NTSM observer is proved by Lyapunov theory. The simulations and experiments prove that chattering is suppressing effectively and the transient response is improved further.The PMSM sensorless digital control system is designed including hardware and software. The observer discretization and simulation implementation are proposed, and the motor control system simulation is build up based on MATLAB. The observer implementation method in fix-point MCU is discussed especially, including data format process, observer digital implementation and power function implementation. The simulation and experiments in each chapter prove that the observer implementation method and control system are effective and feasible.更多还原