Torque ripple minimization of a switched reluctance motor by using continuous sliding mode control technique

This paper proposes a new method to minimize torque ripple of a switched reluctance motor (SRM), which is based on the control of the sum of the square of the phase currents by using only two current sensor and analog multipliers. In addition, the sliding mode control (SMC) technique has been applied to SRM speed control loop that compensates the low frequency oscillations on the torque output. The applied sliding mode controller adjusts the value of the reference current to keep the speed of the motor constant. The proposed sliding mode continuous controller performs better than PI and Fuzzy controllers and is also more robust to the external disturbances. The results show that the continuous sliding mode controller is effective compared to PI or Fuzzy controllers in reducing the torque ripple of the motor, compensating for the nonlinear torque characteristics and making the drive insensitive to parameter variations as well. Since, mutual inductances have an important disturbance effect on the torque ripple, mathematical model of the SRM has been derived in presence of them. It has been used a completely analog system to implement the proposed algorithm. Also, a mechanical sensor has been used to sense the rotor position. Simulation and experimental results are given to validate the proposed method for the self and mutual inductances and current measurements.     

开关磁阻电机的模糊分数阶PID控制算法研究

开关磁阻电机(SRM)的双凸极机械结构和开关工作特性,导致常规控制算法在其调速控制时,存在转矩脉动大、动态性能一般等问题。论文应用分数阶PID控制算法鲁棒性强和模糊控制不依赖于精确数学模型的优点,提出了一种基于模糊分数阶PID转矩控制算法。在适应SRM转矩控制模糊规则表的基础上,以转速偏差和偏差变化率为输入,通过模糊推理自适应调整分数阶PID控制器的比例系数、积分阶次、微分阶次,使SRM的转矩脉动较小。仿真结果表明该算法使开关磁阻电机的转矩脉动较小,动态响应好。     

基于DITC的开关磁阻电动机可逆控制系统

与传统的交直流电动机相比,开关磁阻电动机(Switched Reluctance Motor,简称SRM)的主要缺点是其转矩脉动较大以及由此引起的噪声和振动。通过引入直接瞬时转矩控制(Direct Instantaneous Torque Control,简称DITC),可有效减小SRM控制系统的转矩脉动。介绍了SRM-DITC可逆运行系统的主要组成,并提出了在可逆运行工作模式下的DITC方法。通过仿真和DSP物理实验,验证了所提方法的有效性。     

基于遗传算法和转矩分配函数的开关磁阻电机转矩脉动抑制

开关磁阻电机(SRM)特殊的双凸极结构导致其运行时会产生很强的转矩脉动。传统的转矩分配函数(TSF)控制方法虽然可以在一定程度上起到抑制转矩脉动的作用,但是受到开关频率、功率电源电压值等物理条件的限制,仍会存在较大的转矩脉动。为此,提出了一种基于遗传算法的SRM TSF控制方案。利用遗传算法良好的寻优能力,在指数型TSF控制的基础上,将转矩脉动作为优化目标来寻取最优的开关角。将1台四相8/6极的SRM作为研究对象,搭建了以TMS320F28335为控制核心的试验平台。试验结果验证了基于遗传算法的TSF控制方法可以有效减小SRM的转矩脉动。     

基于模糊PI控制的永磁同步电机转速脉动抑制

高精度宽调速范围伺服系统研究的内容之一是转速脉动抑制问题.在给出了含有脉动量的转矩模型基础上,针对该脉动量的不确定性,提出了在系统速度环上利用参数自整定PI模糊控制器实现减小转速脉动的方法,经与常规PI控制器仿真比较,该控制器性能良好,并使系统具有较强的鲁棒性.     

电动车用开关磁阻电机转矩控制器设计与优化

电动汽车用开关磁阻电机转矩动态特性对电动汽车整车动力性能与乘坐舒适性能起着至关重要的作用。为了降低开关磁阻电机转矩脉动,提高其平均转矩,达到优化转矩动态特性的目的,在MATLAB/Simulink环境中建立了开关磁阻电机非线性动态模型;利用动态模型仿真数据确立了电机转矩动态性能与转速、关断角之间的函数关系;以降低转矩脉动,提高平均转矩为目标,建立了最优关断角与转速之间的函数关系;设计了基于可变关断角的转矩优化控制器。仿真结果表明,本文建立基于可变关断角的转矩优化控制器能很好地降低转矩脉动,提高平均转矩,达到了优化开关磁阻电机转矩动态特性的目的。     

ACO based speed control of SRM fed by photovoltaic system

This paper proposes a speed control of Switched Reluctance Motor (SRM) supplied by Photovoltaic (PV) system. The proposed design of the speed controller is formulated as an optimization problem. Ant Colony Optimization (ACO) algorithm is employed to search for the optimal Proportional Integral (PI) parameters of the proposed controller by minimizing the time domain objective function. The behavior of the proposed ACO has been estimated with the behavior of Genetic Algorithm (GA) in order to prove the superior efficiency of the proposed ACO in tuning PI controller over GA. Also, the behavior of the proposed controller has been estimated with respect to the change of load torque, variable reference speed, ambient temperature, and radiation. Simulation results confirm the better behavior of the optimized PI controller based on ACO compared with optimized PI controller based on GA over a wide range of operating conditions.     

基于新型趋近律和混合速度控制器的IPMSM调速系统滑模变结构控制

为了提高内置式永磁同步电机(IPMSM)调速系统的动、静态性能,提出了一种基于新型变速趋近律的滑模控制器,该新型趋近律基于反双曲正弦函数,根据系统状态量,采取变带宽趋近方式,可有效抑制系统的稳态转矩脉动。为解决滑模控制中电机起动时响应速度快与起动电流大的矛盾,提出了一种基于PI和滑模控制(SMC)的混合速度控制器(HSC),该混合速度控制器中滑模控制基于新型趋近律,通过控制器输入值的大小选择控制方式,有效解决了上述矛盾问题,且该控制器可进一步提高系统的响应速度并能进一步抑制稳态转矩脉动。通过仿真和实验,验证了该速度控制器和该新型趋近律的可行性以及有效性。     

Robust Sliding Mode Speed Controller-based Model Reference Adaptive System (MRAS) and Load Torque Estimator for Interior Permanent Magnet Synchronous Motor (IPMSM) Drives

This paper presents a robust sliding mode control (SMC)-based model reference adaptive system (MRAS) aimed at improving the dynamic performance of interior permanent magnet synchronous motor (IPMSM) drives. MRAS following a speed controller for IPMSM drives is developed. The error signal between the plant speed and MRAS speed is augmented to permit the prescribed specifications be maintained using SMC. The load disturbance is detected using a load torque estimator and is compensated through the q-axis current reference value. The load torque estimator is used to provide a feedforward value in the speed controller in order to decouple the load torque from the speed control. This method can improve IPMSM dynamic performance against the disturbance torque without increasing SMC gain due to both chattering and stability limitations. The complete field-oriented control of an IPMSM drive with the proposed controller is successfully implemented in real time using the DSP-DS1102 control board for a laboratory 1-hp motor. A performance comparison of the proposed controller with the conventional PI controller is also provided. The efficacy of the proposed controller is verified by simulation and experimentation under different operating conditions. It is found that the proposed controller provides an excellent speed response under load torque disturbance and parameter uncertainty.     

永磁同步电机新型直接转矩控制系统设计

针对传统的直接转矩控制转矩脉动大、开关频率不恒定等问题,在分析永磁同步电机数学模型的基础上,综合矢量控制的特点,提出一种基于空间矢量脉宽调制的新型直接转矩控制系统,用PI调节器取代滞环控制器,用空间矢量脉宽调制取代开关表.同时为了提高系统性能,模糊控制被应用于该系统.在Matlab环境下建立永磁同步电机新型直接转矩控制系统仿真模型并进行仿真研究,仿真结果证明了新型直接转矩控制系统设计可行有效,在提高系统响应速度的同时,能有效减小转矩和磁链的脉动,改善控制系统的性能.     

An automatic torque ripple compensation system for direct drive motors

A serious problem in motion control is the occurrence of torque ripple. Since a direct drive (DD) motor with a magnet rotor uses a rare-earth magnet, the torque ripple is more serious than that of conventional servomotors. This paper presents an auto-compensation of torque ripple using a software-implemented torque observer. The frequency and amplitude of torque ripple can be obtained in the controller by using the estimated torque from an observer, and the autonomous generation of a compensating current component for a torque ripple is possible. The proposed algorithm has been verified by experiments.     

基于PWM的开关磁阻电机直接瞬时转矩控制

针对开关磁阻电机(SRM)转矩脉动过大的问题,提出一种结合直接瞬时转矩控制(DITC)和脉宽调制的控制方法。该方法依据SRM的转矩特性进行扇区划分,将三相SRM的一个电角度周期划分为9个扇区;同时给出转矩滞环大小的选取原则,在运行时能自适应地调整滞环大小。此外,不同于传统DITC,在每个采样周期内只选取基础电压矢量进行控制,该方法根据运行状况以及优化后的导通规则对每相电压占空比进行实时调整得到合适的电压矢量。通过Matlab/Simulink仿真及实验样机平台验证,证明了所提方法可以解决传统DITC存在的电流脉动大等诸多缺陷,并使DITC适用于较低的转矩环采样频率,在开关磁阻电机型电动车研制领域具有较高的应用价值。     

Evolutionary computation based multi-objective pole shape optimization of switched reluctance machine

This paper presents the application of elitist Non-dominated Sorting Genetic Algorithm version II (NSGA-II) to determine optimum pole shape design for performance enhancement of Switched Reluctance Machine (SRM). In SRM, torque output and torque ripple are sensitive to stator and rotor pole arcs and their selection is a vital part of SRM design process. The problem of determining optimal pole arc is formulated as a multi-objective optimization problem with the objective of maximizing average torque, minimizing torque ripple and copper loss. In order to account for the geometry as well as for the nonlinearity of material utilized, the Finite Element Method (FEM) is used to determine the performance of the machine. The proposed optimization technique is applied to determine optimal pole shape of an 8/6, four-phase, 5 HP, 1500 rpm SRM. The results show the effectiveness of the proposed approach and confirm the application of NSGA-II as a promising tool for solving SRM design problems. The results obtained by NSGA-II are compared and validated with classical multi-objective approach based on weighted sum method using Differential Evolution (DE) algorithm.     

开关磁阻电动机转矩控制的研究

文章着重讨论开关磁阻电动机驱动系统（SRD）的控制器设计,比较了电流控制器和磁链控制器的性能及输出转矩,以优化转矩输出、最小化转矩脉动。这种控制器因输入变量的不同其设计方法上有各自不同的考虑,而且它们对控制对象SRM性能影响也不同。文章比较了两者作用下SRM转矩输出结果并给出了相应结论。     

非线性模型的开关磁阻电动机转矩脉动抑制

针对开关磁阻电动机SRM(Switched Reluctance Motor)转矩脉动大的问题,基于SRM的磁化特性,分析了SRM的非线性模型.采用Matlab/Simulink仿真软件,对SRM、功率变换器及其控制系统建立了动态仿真模型,并用模糊控制器对SRM的关断角进行实时补偿,实现SRM关断角自动调节,达到减小转矩脉动的目的.仿真实验中,转矩脉动系数从补偿前的0.673 0降低到补偿后的0.257 4,证明了该方法的可行性和有效性,为实际SRM控制系统的设计和调试提供了有效的手段和工具.     

无速度传感器永磁同步电机的SVM-DTC控制

为改善常规基于常值切换的滑模转速观测器的低速性能，提出采用修正的指数趋近滑模和扩展卡尔曼滤波结合的方式进行速度估计。针对直接转矩控制低速时转矩脉动大的问题，采用基于模糊网络与PI控制结合的转矩角调节器来改进控制效果。仿真结果表明提出的速度估计器较常规滑模观测器的动态响应快，速度估计更为准确。改进的SVM-DTC方案的转矩角计算合理，转矩响应脉动减少，性能优于常规恒定PI系数的SVM-DTC。     

基于Supertwisting滑模永磁同步电机驱动的转速和转矩控制

针对永磁同步电机(PMSM)空间矢量的直接转矩控制方案超调频繁、响应时间慢等问题,将传统的转速PI控制器和转矩PI控制器替换成Super-twisting滑模控制器,并从理论上证明了Super-twisting滑模控制器用在转速环和转矩环上能在有限时间内收敛。借助MATLAB/Simulink仿真软件研究了PMSM的转矩脉动,分析了其动态响应速度。仿真结果表明,在空间矢量直接转矩控制中采用Super-twisting滑模控制器与PI控制器相比有更小的转矩脉动,提高了动态响应速度并且解决了超调频繁的问题。     

基于定子电阻补偿的PMSM直接转矩控制

传统直接转矩控制的缺点之一是转矩脉动较大,而定子电阻变化是导致低速转矩脉动产生的一个重要原因.提出了一种使用PI控制器的定子电阻补偿原理减小转矩脉动的方案,PI控制器的输入是实际磁链值和参考磁链值,输出是定子电阻的变化值.仿真结果表明,与传统直接转矩控制算法相比,该方案能显著减小转矩脉动,而且整个算法简单,容易实现.     

Control and operation of a new 8/6-pole doubly salient permanent-magnet motor drive

This paper proposes a new 8/6-pole doubly salient permanent-magnet (DSPM) motor drive, which offers the advantages of higher power density, higher efficiency, and wider speed range. The corresponding control and operation of the motor drive are presented. A variable proportional-integral (PI) controller combined with bang-bang control for the DSPM motor drive is developed. Two operation modes, namely, four-phase and two-phase operation modes, are proposed for the 8/6-pole DSPM motor drive. The drive system is implemented and tested. The results show that the developed control scheme can operate the DSPM motor properly, and the DSPM motor drive offers high efficiency over wide power range and good dynamic performance. Furthermore, the two-phase operation mode of the 8/6-pole DSPM motor offers the possibility of eliminating the torque ripple of the motor drive.     

COMPARISON OF CONTROL STRATEGIES TO MINIMIZE THE TORQUE RIPPLE OF A SWITCHED RELUCTANCE MACHINE

ABSTRACT

The Switched Reluctance Machine (SRM) presents simple structure with passive rotor without windings nor any magnets. That enables applications in mass production (low production and material costs) or in harsh environments (high temperature...). Unfortunately, its polyphase torque is naturally pulsed because of the highly nonlinear electromagnetic characteristics and because the phases have to be successively commutated in order to maintain a continuous rotation. A torque control associated with an appropriate strategy for the phase commutation is thus sought in order to reduce the torque ripple. Initially, the limits of the classical linear control (Proportional Integral controller) are determined. Then, the performances of the PI controller are improved by means of electromotive forces compensation. Nevertheless, the torque ripple remains significant. In order to compensate for SRM nonlinearities, we propose a nonlinear torque control associated with a suitable commutation strategy. This control has been simulated and experimentally tested. Its performances have been compared with the PI-obtained performances. Very promising results have been obtained at low and medium speeds. However, even with this nonlinear torque control, torque ripple still remains in the presence of voltage saturation. This is precisely why we are presenting herein an original method, which enables compensating for the effects of the feeding-voltage saturation.