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.     

Robust sliding mode control and flux observer for induction motor using singular perturbation

This paper proposes a sequential methodology for designing a robust adaptive sliding mode observer for an induction motor drive using a two-time-scale approach. This approach is based on the singular perturbation theory. The two-time-scale decomposition of the original system of the observer error dynamics into separate slow and fast subsystems permits a simple design and sequential determination of the observer gains. In the proposed method, the stator currents and rotor flux are observed on the stationary reference frame using the sliding mode concept. The control algorithm is based on the indirect field oriented sliding mode control with an on-line adaptation of the rotor resistance to keep the machine field oriented. The control–observer scheme seeks to provide an asymptotic tracking of speed and rotor flux in spite of the presence of an uncertain load torque and an unknown value of rotor resistance. The validity for practical implementation has been verified through computer simulations.     

Very low speed and zero speed estimations of sensorless induction motor drives

Recently, speed sensorless control of induction motor drives received great attention to avoid the different problems associated with direct speed sensors. However, low speed operation with robustness against parameter variations remains an area of research for sensorless systems. Stator resistance is of utmost importance for good operation of speed sensorless systems in low speed region. In this paper, a sliding mode current observer for an induction motor is presented. An estimation algorithm based on this observer in conjunction with Popov's hyper-stability theory is proposed to calculate the speed and stator resistance independently. The proposed speed observer with parallel stator resistance identification is first verified by simulation. Experimental results are included as well as to demonstrate the good performance of the proposed observer and estimation algorithms at very low and zero speeds.     

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。     

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。     

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.     

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。     

Analysis of rotor slotting saliency in induction motor sensorless control

This paper deals with induction machines study by Finite Element Analysis (FEA) for position sensorless control drives based on rotating voltage carrier injection. It focuses the analysis of the rotor slotting saliency, under the variations of: (1) supply of the machine (both the high frequency rotating voltage carrier and the fundamental frequency supply), (2) reference flux of the drive, (3) load torque, and (4) rotor geometry design. The relative spatial harmonic of the stator inductance space-vector responsible for the rotor slotting effect has been chosen as an index for evaluating the response to the high frequency carrier. A methodology for retrieving the stator inductance space-vector from a FEA is proposed as well. Results of the variation of the rotor slotting spatial harmonic of the stator inductance with the carrier frequency, the rotor flux linkage, the load torque and the rotor geometry are presented.     

基于滑模观测器的无传感器永磁同步电机矢量控制系统

本文在深入分析永磁同步电机数学模型的基础上,将滑模变结构控制应用于永磁同步电机控制系统中,根据永磁同步电机的数学模型,设计了一个滑模变结构控制器,用于估算电机转子位置和速度;根据磁场定向控制理论,利用估算的转子角度实现了无传感器矢量控制.实验结果表明,滑模变结构控制器对系统参数变化、外界环境的扰动以及内部的摄动具有很强的鲁棒性,能够在全频率范围内追踪实际信号,实现对转轴位置的观测.     

基于改进滑模观测器的SPMSM无位置传感器矢量控制系统

将用于预测永磁同步电机转子位置和转速的滑模观测器进行了改造,并构建了无位置传感器的矢量控制系统;并在此基础上提出了一种用于补偿转子位置角预测误差的改进方法。最后用Matlab仿真验证了算法的有效性,对结果进行了分析讨论。     

基于PLL自适应滑模观测器的PMSM无传感器控制

针对传统滑模观测器无传感器控制方法反电动势基波中高频谐波含量高、抖振严重以及转子位置估计误差大等问题,提出了一种锁相环结构(PLL)自适应滑模观测器永磁同步电机无传感器控制方法。首先,在满足Lyapunov稳定性的前提下,推导并建立了反电动势的自适应律,通过构造自适应滑模观测器,使得反电动势观测误差迅速衰减;同时采用带有消除旋转影响环节的锁相环得到转子位置,消除了转速变化的影响,进一步提高了观测精度;最后,在一台2.9 kW表贴式永磁同步电机上进行了实验验证。实验结果表明,该方法有效地抑制了滑模抖振,降低了反电动势中的高频谐波,提高了转子位置的观测精度。     

MRAS-based sensorless control of a vector controlled five-phase induction motor drive

Multi-phase ac motor drives are nowadays considered for various applications, due to numerous advantages that they offer when compared to their three-phase counterparts. In principle, control methods for multi-phase machines are the same as for three-phase machines. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information of the rotor speed is extracted from measured stator currents and voltages at motor terminals. Vector controlled drives require estimating the magnitude and spatial orientation of the fundamental magnetic flux waves in the stator or in the rotor. Open-loop estimators and closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an open-loop and model reference adaptive system (MRAS)-based sensorless control of vector controlled five-phase induction machine with current control in the stationary reference frame. The MRAS-based sensorless operation of a three-phase induction machine is well established and the same principle is extended in this paper for an IRFOC five-phase induction machine. Performance, obtainable with hysteresis current control, is illustrated for a number of operating conditions on the basis of simulation results. Full decoupling of rotor flux control and torque control is realised. Dynamics, achievable with a five-phase vector controlled induction machine, are shown to be essentially identical to those obtainable with a three-phase induction machine. Experimental verification is also provided.     

一种异步电机无速度传感器间接磁场定向控制策略

针对无速度传感器异步电机,提出了一种新的滑模磁通和速度观测方法。实际电流和观测电流之间的误差收敛到零,保证磁通观测器的精确性。根据估计的定子电流和转子磁链来估计转子的转速和转子时间常数。估计的转子时间常数用于滑模计算和观测器结构中,估计的转速用来作为转速调节的反馈。仿真结果证明所提出的速度估算方法有效以及所提出的观测器结构具有鲁棒性。     

感应电机滑模变结构控制系统的半实物仿真

滑模变结构控制非常适用于高阶非线性系统,但如何快速而有效地验证此类先进控制算法是开发人员面临的主要问题。基于此,针对大功率高性能调速控制系统,提出了快速验证的半实物仿真方案。首先,设计出基于滑模变结构控制的感应电机电流内环控制策略,在分析半实物仿真机理的基础上,搭建了滑模变结构控制系统的实时仿真模型,实现了系统硬件在环仿真,并分别对PI控制和滑模变结构控制的电流控制效果进行了对比实验。结果表明,滑模变结构控制策略在动态性能和抗负载扰动性能方面具有明显优势,半实物方案对先进控制算法的有效验证和应用具有重要意义。     

Design of a new adaptive sliding mode observer for sensorless induction motor drive

This paper proposes a new speed and flux estimation method which has the robustness against the variation of the electrical parameters of the motor and the superiority in the dynamic characteristics. In the proposed method, the stator currents and the rotor fluxes are observed on the stationary reference frame using the sliding mode concept. And the rotor speed is estimated using the current estimation errors and the observed rotor fluxes based on the Lyapunov stability theory. Also a design method of the observer gain using H₈ norm is proposed to minimize the effect of the speed estimation error on the rotor flux observation. The experimental results are shown to verify that the proposed method shows the excellent performances under the variations of motor resistance and inductance.     

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。     

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。     

Validation of an integral sliding mode control for optimal control of a three blade variable speed variable pitch wind turbine

Reduction in cost of wind energy requires most efficient control technology which can able to extract optimum power from the wind. This paper mainly focuses on the control of variable speed variable pitch wind turbine (VSVPWT) for maximization of extracted power at below rated wind speed (region 2) and regulation of extracted power when operating at above rated wind speed (region 3). To extract maximum power at below rated wind speed torque control is used whereas to regulate rated power at above rated wind speed pitch control is used. In this paper a nonlinear control i.e. integral sliding mode control (ISMC) is proposed for region 2 whereas a conventional proportional–integral (PI) control is adapted for region 3 of a VSVPWT. The proposed controller is combined with modified Newton Raphson (MNR) wind speed estimator to estimate the wind speed. The stability of the proposed ISMC is analyzed using Lyapunov stability criterion and the control law is derived for region 2 which is also adapted for the transition period between region 2 and region 3 (region 2.5). The dynamic simulations are tested with nonlinear FAST (Fatigue, Aerodynamics, Structures, and Turbulence) wind turbine (WT). The simulation results of ISMC are presented and the control performance is compared with conventional SMC and existing controllers such as aerodynamic torque feed forward control (ATF) and Indirect speed control (ISC). It is seen that especially in region 2.5, ISMC gives better performance compared to all other controllers.     

一种新的异步电动机调速系统的混合控制方法

矢量控制(FOC)和直接转矩控制(DTC)是目前高性能异步电动机调速系统中的两种主要控制方法.研究和工程实践表明,这两种方法各有优缺点,国内外很多学者也提出了很多方案,试图改进和完善这两种控制方法.本文从全新的思路出发,尝试把这两种方法结合到一个控制系统中,取长补短,形成一种新的混合控制方法.该方法使用户可以根据实际运行的不同需要,在线灵活地切换到合适的控制方法(FOC或DTC),以提高控制性能.为了实现两种控制方法之间的平滑切换,本文把传统的PI控制器改造成可重置PI控制器.仿真和实验结果表明,这种可重置PI控制器可以有效减少FOC和DTC切换时造成的系统波动,同时能保持原有控制系统的性能,提高了本文提出的混合控制方法的实用价值.     

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.