A robust sliding mode flux and speed observer for speed sensorless control of an indirect field oriented induction motor drives

In this paper a new sliding mode flux and speed observer is proposed for indirect field oriented induction motor drive system. The error between the actual and observed currents converges to zero, which guarantees the accuracy of the flux observer. The rotor speed and the rotor time constant are estimated based on the estimated stator currents and rotor flux. The estimated rotor time constant is used in slip calculation and observer structures and the estimated speed is used as feedback to the speed regulation. Computer simulation and experimental results of the speed control verify the validity of the proposed speed estimation algorithm. The experimental results show the robustness and performance of the proposed observer structure. Experimental results have been realized without load, with load and with external disturbances.     

Implementation of a closed loop sliding mode observer for speed sensorless control of an indirect field oriented induction motor drives

A new sliding mode flux and speed observer is proposed for indirect field oriented induction motor drive system. The error between the actual and observed currents converges to zero, which guarantees the accuracy of the flux observer. The rotor speed and the rotor time constant are estimated based on the estimated stator currents and rotor flux. The estimated rotor time constant is used in slip calculation and observer structures. The estimated speed is used as feedback to the speed regulation. Simulation and experimental results of the speed control verify the validity of the proposed speed estimation algorithm.     

一种用于异步电机无速度传感器控制的自适应滑模观测器

针对异步电机无速度传感器中存在的对参数变化鲁棒性差的问题,研究了一种基于自适应滑模观测器的异步电机无速度传感器的矢量控制方案。自适应滑模观测器根据电机静止坐标系下的数学模型构造了转子磁链观测器,定子电流观测值与实际值的误差构成观测器的滑模面,在滑模运动下该观测器的观测值最终趋近于实际值,从而实现转子磁链的估计。电机转速由自适应方法估算得到,滑模观测器的稳定性可由李雅普诺夫稳定性证明。与其他方案相比,该方法的优点在于实现简单,对参数变化具有鲁棒性。仿真和实验对控制方案的正确性和可行性给出了验证,该观测器可以实现对转子磁链和转速的观测,且在负载扰动和给定转速变化的情况下该滑模观测器具有鲁棒性。     

基于二阶滑模观测器的感应电机转子磁链观测

实现矢量控制的基础是准确获得转速和转子磁链信息,本文提出了一种基于二阶滑模观测器的转子磁链观测方法。将构造的滑模观测器作为模型参考自适应系统(MRAS)的参考模型,将磁链的电流模型改造为该中间变量的可调模型,且其可调量为转速变量,进而构造出MRAS,实现对转速的观测。在此基础上,完成转子磁链的计算,并得到转子磁链角度,实现基于直接磁场定向的感应电机矢量控制。中间量的构造有效避免了传统MRAS中的纯积分问题,便于算法的实施;二阶滑模观测器有效地削弱了一阶滑模观测器存在的抖振扰动,并且参数具有较强的鲁棒性。仿真结果表明该转子磁链观测器具有较高的观测精度,且对外部扰动和转子电阻变化具有较强的鲁棒性,提高了系统的动稳态性能。     

Artificial intelligence-based speed control of DTC induction motor drives—A comparative study

The design of the speed controller greatly affects the performance of an electric drive. A common strategy to control an induction machine is to use direct torque control combined with a PI speed controller. These schemes require proper and continuous tuning and therefore adaptive controllers are proposed to replace conventional PI controllers to improve the drive's performance. This paper presents a comparison between four different speed controller design strategies based on artificial intelligence techniques; two are based on tuning of conventional PI controllers, the third makes use of a fuzzy logic controller and the last is based on hybrid fuzzy sliding mode control theory. To provide a numerical comparison between different controllers, a performance index based on speed error is assigned. All methods are applied to the direct torque control scheme and each control strategy has been tested for its robustness and disturbance rejection ability.     

Robust disturbance attenuation with unknown input observer and sliding mode controller

For a linear system with mismatched disturbance, a robust sliding mode control algorithm using only output feedback is developed in this paper. Although the system with intrinsic issues of unknown input and nonminimum phase is inherited, an improved reduced-order unknown input observer is to be presented in estimating the state of the system. The manipulation of H _∞ control theory along with the implementation of estimated system state can result in robust stabilization with disturbance attenuation when designing integral sliding surface of a system in the sliding mode. A controller is also designed to satisfy the reaching and sliding condition in line with the estimated system state. Finally, a numerical example is explained for showing the applicability of the proposed scheme.     

考虑滑模抖振的永磁同步电机模糊超螺旋滑模观测器

针对永磁同步电机控制系统中的传统滑模观测器在估计转子位置与转速时出现的抖振问题,设计一种基于模糊规则的超螺旋滑模观测器。该观测器利用串联高阶滑模结构特点来保证输出的连续性,以此削弱滑模控制中高频切换带来的抖振。而模糊规则的引入以解决超螺旋控制算法中边界函数的上界在实际中很难获得的问题,然后利用反证法验证所提出的模糊超螺旋滑模控制率的收敛性。最后在Matlab中搭建模型,实验结果表明所设计控制方案在满足控制精度的同时,减弱了系统抖振。     

永磁直线同步电机的双滑模观测器的设计

针对永磁同步直线驱动系统中存在双时间尺度特性,利用奇异摄动理论将永磁直线驱动系统分解成快变、慢变子系统,对快、慢变子系统分别设计了滑模位置观测器和滑模速度观测器。通过这两个观测器可以只利用便于测量的定子电流和电压来估计永磁直线同步电动机的磁极位置和线速度,消除了传统上使用位置和速度传感器所带来的诸多不利。仿真结果表明,所设计的双滑模观测器不仅能准确地估计磁极位置和线速度,实现无传感器控制,而且在系统模型存在不确定性和测量噪声时仍具有较好的鲁棒性。     

基于反电动势滑模观测器的异步电机矢量控制

为提高异步电机无速度传感器控制参数鲁棒性,同时减小滑模抖振,研究了一种基于反电动势高阶滑模观测器的异步电机速度观测和矢量定向方案。在对异步电机数学模型变换的基础上,通过非奇异终端滑模观测器的设计,实现了对反电动势的准确观测。据此设计了转速适应率,实现了转速观测,并由反电动势和转子磁链之间的故有相位关系,实现了转子磁场的直接定向。该方案的突出优势在于其较强的参数鲁棒性:一方面,其矢量定向的准确性不受转子电阻这一易变参数的影响;另一方面,转子电阻的变化对速度观测精确度的影响较小。同时高阶滑模观测器的设计有效地抑制了滑模抖振,提高了观测精确度。仿真结果验证了该方案的有效性,展示了其较强的参数鲁棒性。     

基于超螺旋滑模观测器的永磁同步直线电机无模型控制

针对永磁同步直线电机(permanent magnet linear synchronous motor, PMLSM)在运行过程中因参数失配和外部扰动导致控制性能下降的问题,提出一种基于超螺旋滑模观测器的永磁同步直线电机无模型控制策略。根据PMLSM在dq旋转坐标系下参数摄动时的数学模型建立电机对应的新型超局部模型,以避免参数失配。基于该新型超局部模型,结合滑模控制设计了无模型滑模速度控制器,通过Lyapunov稳定性理论证明该控制器的稳定性。同时,为削弱传统扩展滑模观测器对新型超局部模型中未知量观测的抖振,提高控制精度,设计超螺旋滑模观测器(super-twisting sliding mode observer, STSMO)对未知量进行在线辨识并实现前馈补偿。最后,将传统滑模控制、基于传统扩展滑模观测器的无模型控制算法与所提方法进行仿真和硬件在环实验对比,结果表明所提方法改善了PMLSM控制系统的动态响应性能,具有较强的鲁棒性。     

基于超螺旋滑模观测器的永磁同步电机无速度传感器控制方法

由于永磁同步电机在低速运行时,电机反电动势较小,因此采样通道的非线性导致的采样电压和电流中包含的直流偏置对电机反电动势观测的影响更为严重。针对这个问题,提出了一种基于超螺旋滑模观测器的永磁同步电机无速度传感器控制方法。首先,基于等效反馈的概念,设计了一种新的超螺旋滑模观测器,以提高低速时的无速度传感器控制精度;其次,详细分析了直流偏置对无速度传感器控制的影响,并且设计了一种基于二阶广义积分器的直流偏置抑制方法,从而进一步提高了无速度传感器控制精度;最后,通过6.6 kW永磁同步电机无速度传感器控制系统验证了所提控制策略的有效性。     

感应电机磁链和转矩的非奇异终端滑模控制

针对直接转矩控制技术以容差形式的Bang-Bang控制模式给系统的稳态运行带来的转矩脉动大、电流谐波成分重、定子磁链轨迹畸变等问题,将非奇异终端滑模控制应用到了转矩和磁链控制中.为了提高传统滑模控制的收敛性,分别独立设计了转矩控制器和磁链控制器的非奇异终端滑模平面.转矩控制器和磁链控制器由等效控制项和非线性切换项组成,非线性切换项中的符号函数sgn(S)通过积分作用削弱了控制量的抖振.仿真结果表明,非奇异终端滑模变结构直接转矩控制具有动态响应快、转矩波动和转速波动小、鲁棒性强、低"抖振"的特点.     

基于二阶滑模观测器的永磁同步电机无位置传感器控制

为了准确估计永磁同步电机的转子位置与速度,提出一种二阶滑模观测器.该观测器在传统线性滑模面基础上引入了混合非奇异终端滑模面,避免了常规滑模观测器由于低通滤波所产生的相位滞后问题,同时可以提高转子位置与速度的估算精度.为了保证观测器的稳定并抑制滑模固有的抖振现象,设计了滑模控制律.最后,采用具有锁相功能的转子位置与速度跟踪算法从观测的反电动势中解调出转子位置和速度信息.仿真和实验证明了所提观测器的正确性.     

Application of reaching law approach to the position control of a vector controlled induction motor drive

In this paper, a new position control method based on the reaching law control (RLC) approach is proposed for the robust position control of electrical drive systems. The main aim of this study is to investigate the robustness of the RLC approach under inertial-frictional variations and external disturbances and to address the application problems of the RLC approach for position control systems. New components are added to the controller in order to improve the robustness. The control method is applied to a vector-controlled induction motor drive system. It is shown in the paper that the practical constraints such as torque limitation, and the demand of high control performance, i.e., high bandwidth, result in undesirable overshoots. The performance of the control method is shown by simulation and experimental results.List of symbols X, X _k Continuous and discrete-time state vectors - x ₁, x ₂ State variables (the shaft position and speed of the rotor) - , _re Position and reference angles (rad) - Angular velocity (rad/s) - A,A _n State variable matrix with true and nominal parameters - B,B _n Control input matrix, with true and nominal parameters - u,u _max Control signal, and its maximum value - A,B Uncertain parts of the state matrix and the control input matrix - Equivalent terms of A, B uncertainties referred to matching condition - C Gain vector of switching function - s _k Switching function - q A constant used in the reaching law - A constant used in the reaching law - A constant used in the chattering reduction approach - T sampling period - J,J _n True and nominal inertia coefficient (kg m²) - B,B _n True and nominal friction coefficient (kg m²/s) - J,B The uncertain parts of the inertia and friction coefficients - T _e Produced (electrical) torque (control signal) (Nm) - Load torque (Nm) - Equivalent term of A referred to matching condition and scalar component - Equivalent term of B referred to matching condition - All uncertainties and disturbances referred to matching condition - J₀,B₀ The variation ratios of the inertia and friction coefficients - G State variable matrix in discrete-time model - H Control input matrix in discrete-time model - Slope of the sliding line (surface) - a Mechanical time constant - v _sd, v _sq Stator voltages in d-q axis (V) - i _sd, i _sq Stator currents in d-q axis (A) - L _s, L _R Stator and rotor self inductances (H) - L _m Mutual inductance (H) - Leakage factor - _e, _sl Stator and slip angular velocity (rad/s) - _r Rotor time constant - P Number of poles     

Observer-based nonlinear control of power system using sliding mode control strategy

This paper presents a new transient stabilization with voltage regulation analysis approach of a synchronous power generator driven by steam turbine and connected to an infinite bus. The aim is to obtain high performance for the terminal voltage and the rotor speed simultaneously under a large sudden fault and a wide range of operating conditions. The methodology adopted is based on sliding mode control technique. First, a nonlinear sliding mode observer for the synchronous machine damper currents is constructed. Second, the stabilizing feedback laws for the complete ninth order model of a power system, which takes into account the stator dynamics as well as the damper effects, are developed. They are shown to be asymptotically stable in the context of Lyapunov theory. Simulation results, for a single-Machine-Infinite-Bus (SMIB) power system, are given to demonstrate the effectiveness of the proposed combined observer-controller for the transient stabilization and voltage regulation.     

感应电机无速度传感器控制自适应速度观测器

理论与实践证明自适应速度观测器是实现高性能的感应电动机无速度传感器控制系统的有效方法之一。由于该系统的非线性性质,在观测器设计以及系统应用中还有许多有待解决的问题。针对此类问题,从理论联系实际的角度,分析现有的电机磁链、速度观测器理论的要点及其成果,如建模的条件、自适应速度估计算法及其物理性质、系统稳定性分析、线性化方法、以及观测器参数的辨识等。同时,给出了实验结果、指出了这些内容中尚存的相关问题。     

Deadbeat flux level control of direct-field-oriented induction motor

A method for the deadbeat flux level control of a direct-field-oriented induction motor with position control loop has been developed that employs an adaptive rotor flux observer. The observer is a full-order type and is used not only in the direct-field-oriented controller, but also to identify stator and rotor resistances of the motor. The observer reduces the sensitivity of a deadbeat controller to fluctuations in the motor parameters. The main advantage of this method is that it improves the efficiency of an induction motor without sacrificing dynamic performance. This paper describes the method as well as the fundamental characteristics of the system derived from experimental and simulation results.     

一种永磁同步电机新型高阶滑模观测器设计

为了提高无位置传感器控制的精度,增强控制系统的鲁棒性,减小不确定扰动的影响,提出了一种新型高阶滑模观测器。该设计使用改进的积分滑模定子电流观测器估算永磁同步电机的反电动势,从而分析得出转子位置和转速估算值。在指数趋近律的设计上,等速项用连续光滑的开关函数代替不连续的符号函数,指数项引入随系统的变化而调整的增益项。通过仿真实验,验证了该滑模观测器对改善转子位置和速度估算精度有明显的提升效果,增强了系统的鲁棒性,抑制了抖振现象。     

Compensation of stator iron loss of vector‐controlled induction motor using robust flux observer

A new vector control system of an induction motor is proposed in this paper to reduce the influence of iron loss, which has been difficult to deal with. Recently, many methods have been proposed to improve the accuracy of torque control, concentrating on the identification of parameters and the adjustment of the controllers. But, it is necessary for experts to tune parameters initially in those methods. The new method can reduce the influence of iron loss by using a robust flux observer. By adding current decoupling control for compensation of the iron loss, a vector control system with high torque linearity can be constructed. © 2001 Scripta Technica, Electr Eng Jpn, 137(3): 59–66, 2001     

采用滑模观测器的SGCMG框架伺服系统研究

针对框架伺服系统中应用的传统机械式角度测量传感器存在增加系统尺寸、重量和成本以及安装传感器会引起系统误差和降低系统可靠性等问题，基于TMS320F28335主控制器和A3PE3000从控制器设计硬件电路进行电信号采集和运算，并提出滑模观测器进行角度估算以替代机械式传感器，角度估算依据硬件电路测得电机绕组中有关精确的电信号，采用建立滑模观测器和基于锁相环算法实现转子位置和速度估算。在Simulink中搭建仿真模型，仿真结果表明，通过滑模观测器估计得到的位置值和速度值在系统运行0.2 s后能够稳定的跟踪上实际值。