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.     

Improving transparency of bilateral control system by sliding mode assist disturbance observer

Transparency is an important indicator to evaluate the performance of a bilateral control system. Uncompensated disturbances in high frequency degrade the transparency in the traditional disturbance observer (DOB) based bilateral control. This paper analyzes the influence of the uncompensated disturbances, and proposes a sliding mode assist disturbance observer (SMADO) to solve the problem. The sliding mode technique helps the original DOB to estimate the disturbances in high frequency by making use of a rapid switching control value. The required switching gain is small in the proposal, which is good for alleviating the chattering. Moreover, to avoid conservative and arbitrary design of the switching gain, a reasonable benchmark is proposed by employing the estimation error between the original DOB and another parallel DOB with a different cutoff frequency. The validity of the proposal is confirmed by experiments. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

具有非线性输入的鲁棒自适应模糊滑模控制

针对一类具有死区非线性输入的SISO非线性系统,基于滑模控制原理,提出了一种稳定自适应模糊控制器设计方案.该方案通过使用积分型Lyapunov函数避免了反馈线性化方法中可能出现的控制器奇异性问题,运用两阶段法构造两个Lyapunov函数,确定出用于建模的有界闭区域,再证明跟踪误差收敛到零.通过理论分析,证明了闭环控制系统全局一致终结有界;仿真结果表明了该方法的有效性.     

A robust current control method with disturbance observer for matrix converter under abnormal input voltage

This paper presents a robust current control method with a disturbance observer for a matrix converter (MC) under an abnormal input voltage. The MC can directly convert power from an input alternating current (AC) source to a load without any direct current (DC) link. Since the MC has no reactive elements, the imbalance and distortion of the input voltage immediately influence the load. Therefore, a high‐performance current control of the load is impossible in this condition. In this letter, we propose a robust current control method for the MC under an abnormal input voltage. Adapting the disturbance observer to a load current control, current control is possible without the influence of the imbalance and distortion of the input voltage and of a fluctuation of a load paramerter, a resistance, an inductance and so on. This current control is robust under these conditions. The proposed method is effective for the application of a high‐performance AC motor drive employing vector control because it is necessary for the proposed method to coordinate with a reference frame. The validity of the proposed method is confirmed by simulation results. © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Hierarchical switching for active disturbance attenuation with fine controller tuning

In this paper, a novel adaptive disturbance attenuation algorithm is proposed combining switching and tuning. A two‐level hierarchical switching logic is developed, which first selects in a short time the potentially best controller among a finite pre‐designed family and then performs a local refinement of its attenuation capability. Thanks to the controller fine tuning, the proposed technique is able to provide a substantial performance improvement in terms of attenuation level as compared with a pure adaptive switching control scheme; at the same time, it retains the positive features of switching‐based approaches, in particular, concerning the possibility of rapidly achieving a satisfactory behavior. Further, an arbitrary attenuation level is ensured in the presence of particular classes of disturbances and provided that it is compatible with robust stability requirement. Simulation results are shown to underline the potential of the approach as a solution to the problem. Copyright © 2016 John Wiley & Sons, Ltd.     

Sliding mode observer for on-line broken rotor bar detection

The major task for any monitoring system is to detect upcoming faults as early as possible. Rotor failures are responsible for a large percentage of total induction motor failures. Thus, a new nonintrusive and in-service approach has been proposed in this paper to detect one broken rotor bar in induction motor using only input quantities information. The method is not affected by the type of load and other asymmetries and it is capable of providing reliable fault diagnose without maintenance specialist intervention. The proposed sensorless technique is based on two real time state space discrete models that are used to estimate the flux of both the stator and the rotor and analyzes the differences obtained in torque when the two models are employed. One of the observers was designed for rotor resistance disturbance rejection. Firstly, simulation results have been conducted and sensitivity and robustness also have been checked for the proposed method. Secondly, an experimental setup has been constructed to implement the new technique in on-line model. The results obtained validate the proposed model and show the reliability of the new method.     

Adaptive unknown input observer approach for aircraft actuator fault detection and isolation

In this paper, an adaptive unknown input observer (UIO) approach is developed to detect and isolate aircraft actuator faults. In a multiple-model scheme, a bank of parallel observers are constructed, each of which is based on a model that describes the system in the presence of a particular actuator fault. The observers are constructed based on a modified form of the standard UIO to generate fault-dependant residual signals, such that when a model matches the system, the residual signal will be zero. Otherwise, the residual will be definitely non-zero and governed uniquely by the faulty signal. For locked actuators and loss of actuator effectiveness, in which the locked position and the reduced effectiveness are additional unknowns, we develop an adaptive scheme to estimate these unknown parameters. To the best of our knowledge, this is the first adaptive UIO presented. We prove that the proposed adaptive algorithms guarantee that both the residual signals and the estimation errors of the unknown parameters converge exponentially when a model matches the plant. By further designing a model-matching index, the fault can be isolated accurately. A condition for the approach is that for an nth order system, there must be n independent measurements available. This requirement limits the applicability of our proposed approach. The condition is certainly satisfied by all state-feedback control systems. However, for some other systems, extra efforts may be needed to increase the number of measurements. The method is applied to a linear model of the F-16 aircraft with controller. The results show that the approach is effective. Copyright © 2006 John Wiley & Sons, Ltd.     

一种不确定非线性系统的滑模变结构观测器的研究

由于工程实际中大部分工业对象均为非线性系统,滑模观测器应用研究的重点已从线性系统转至不确定非线性系统。针对一类非线性满足Lipschitz条件,而不确定部分为有界函数的不确定非线性系统,提出一种滑模变结构观测器设计方案,将基于线性系统提出的Walcott-Zak观测器用于抑制非线性对系统的影响,而滑模变结构使得观测器对系统不确定性具有鲁棒性。对所设计观测器的稳定性进行了证明,并通过仿真验证了所提方法的有效性。     

Sliding mode control for a class of uncertain nonlinear system based on disturbance observer

In this paper, a sliding mode control (SMC) scheme is proposed for a class of nonlinear systems based on disturbance observers. For a nonlinear system, the disturbance that cannot be directly measured is estimated using a nonlinear disturbance observer. By choosing an appropriate nonlinear gain function, the disturbance observer can well approximate the unknown disturbance. Based on the output of the disturbance observer, an SMC scheme is presented for the nonlinear system, and the stability of the closed‐loop system is established using Lyapunov method. Finally, two simulation examples are presented to illustrate the features and the effectiveness of the proposed disturbance‐observer‐based SMC scheme. Copyright © 2009 John Wiley & Sons, Ltd.     

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.     

Sliding mode control with adaptive vss observer

The conventional sliding mode control or variable structure control (VSC) of a nonlinear uncertain system is well known for its robust property and simplicity of control law. However, the use of either is permitted only on the assumption that the upper bound of parameter variation or nonlinearity is known and that the complete information about the state is available. Although the former has recently been solved with adaptive robust control theory, the latter does not appear to be solved. This paper attempted to solve this problem using the technique of VSS adaptive robust control theory. That is, a VSS adaptive observer and a sliding mode control incorporated with this observer was proposed. The robust stability of the closed system can be proved applying Lyapunov's second method.     

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.     

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.     

Cancelation of unknown multiharmonic disturbance for nonlinear plant with input delay

In this paper, a new approach for cancelation of a multiharmonic disturbance is proposed. Compared with a number of known results in this paper, the disturbance cancelation problem is solved when the output variable is measured only, a relative degree of the plant is arbitrary and the control channel has delay. The numerical example is presented to illustrate the theoretical result. The reaction wheel pendulum on a movable platform is considered as the plant to demonstrate that the proposed approach is realizable and can be plugged in practice. The second goal is the development of mechatronic applications for use in education. Copyright © 2011 John Wiley & Sons, Ltd.     

Polynomial fuzzy controller design with disturbance observer using the SOS‐based approach

The polynomial fuzzy model is an effective model to design a fuzzy controller for nonlinear systems. In order to improve the control performance, a so‐called lumped disturbance is considered in the model. For countering the influence of the lumped disturbance, a new fuzzy disturbance observer (FDO) is proposed. Compared to the existing FDO, which is designed on the basis of an individual rule and whose estimate may not match the disturbance properly, the proposed method is able to follow the disturbance, in principle. As a result, the estimate of the new FDO is used directly to synthesize a part of controller along with the regular control input where such a disturbance is not considered. Finally, a set of conditions in the form of the sum of squares for the asymptotic stability of the closed‐loop system is provided. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于扰动跟踪Terminal滑模与多目标零动态的 协调励磁控制器设计

针对电力系统中存在各种扰动和模型不确定性等,为了提高励磁控制的鲁棒性,并考虑机端电压限制,设计了以功角稳定和电压控制为目标的协调励磁控制器。功角稳定控制在Terminal滑模中在线跟踪扰动并进行补偿,构成扰动跟踪Terminal滑模控制,抑制一般扰动和振荡,并能抑制共振型低频振荡;同时设计了多目标零动态滑模控制,在机端电压过限或突变时投入,具有控制功角和提高机端电压性能的功能。稳定控制和电压控制协调切换完成励磁控制。仿真结果表明控制器能在各种扰动时快速稳定功角,并能抑制共振型低频振荡,同时能有效控制机端电     

基于扰动跟踪Terminal滑模与多目标零动态的协调励磁控制器设计

针对电力系统中存在各种扰动和模型不确定性等,为了提高励磁控制的鲁棒性,并考虑机端电压限制,设计了以功角稳定和电压控制为目标的协调励磁控制器。功角稳定控制在Terminal滑模中在线跟踪扰动并进行补偿,构成扰动跟踪Terminal滑模控制,抑制一般扰动和振荡,并能抑制共振型低频振荡;同时设计了多目标零动态滑模控制,在机端电压过限或突变时投入,具有控制功角和提高机端电压性能的功能。稳定控制和电压控制协调切换完成励磁控制。仿真结果表明控制器能在各种扰动时快速稳定功角,并能抑制共振型低频振荡,同时能有效控制机端电压。     

A design of T–S fuzzy controller with disturbance observer

The so‐called lumped disturbance in this paper includes modeling error, external disturbance, unmodeled dynamics, and parameter perturbations. The lumped disturbance and control input do not share the same coefficient matrix in the local Takagi–Sugeno (T–S) fuzzy model. In order to design a proper fuzzy disturbance observer (FDO) and involve the estimate from the FDO into controller to counteract the influence of the disturbance, system equivalence transformation is proposed in this paper. As a result, the conditions for both the asymptotical stability of the closed‐loop system and the convergence of estimation error between the FDO and the disturbance are provided in the manner of linear matrix inequalities (LMIs). Also, computer simulations are provided to illustrate the effectiveness of the proposed FDO‐based control system. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于自适应积分滑模与扰动观测的多PMSM同步控制

为了克服多电机差速失步振荡及同步稳定性变差等问题,提出了基于新型自适应积分滑模和扰动观测的多 PMSM 同步控制方法。首先,构建了一种改进型偏差耦合同步控制结构。其次,设计了基于新型自适应积分滑模(new adaptive integral sliding mode control, NAISMC)的 PMSM 控制器。同时,利用滑模扰动观测器(sliding mode disturbance observer, SMDO)对电机负载扰动进行观测,并与改进的偏差耦合同步控制结构相结合,提出了基于NAISMC与SMDO的多 PMSM 的改进型偏差耦合同步控制方法。最后,进行了实验分析。其结果表明所提出的同步控制方法能有效地保证4个电机具有良好的同步性能,提高了其抗扰动的能力,确保了多电机同步的稳定性。     

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。