开关磁阻电机基于转矩脉动最小化的直接转矩控制技术

开关磁阻电机的主要缺点是转矩脉动较大以及振动和噪声比其他调速系统严重。这里将直接转矩控制技术应用到开关磁阻电机中,以转矩脉动最小化为主要控制目标,在此基础上建立了直接转矩控制的仿真模型。仿真及实验研究表明,直接转矩控制技术能够将磁链矢量幅值很好地控制在滞环带内,从而有效地控制转矩脉动,降低电机的振动和噪声。     

在线转矩分配函数控制开关磁阻电机策略分析

开关磁阻电机(SRM)因双凸极结构,其内部磁场非线性导致运行过程中会产生较大的噪声和转矩脉动。根据开关磁阻电机数学模型,以四相8/6极SRM作为研究对象,用Matlab/Simulink搭建基于在线TSF策略的转矩脉动控制系统模型。系统将实时转矩跟踪参考转矩,将不确定性因素进行整体逼近减小误差,实现在线TSF控制。仿真结果表明,所提系统建模方法能有效地抑制转矩脉动,并增加其稳定性,为实际电机控制系统的设计提供新的思路及参考依据。     

新型建模及优化方法在BSRM中的应用

针对电机参数优化设计问题,引入多支持向量机与混沌优化算法,优化设计磁悬浮开关磁阻电机的结构参数。采用有限元仿真建立样本空间,采用多支持向量机构建磁悬浮开关磁阻电机的非参数模型,基于该模型,以满足额定电磁转矩为条件,优化电机参数,优化目标为最大的悬浮力、最小的转矩脉动、最小的绕组间互感,最优的电机结构参数通过混沌优化算法得到。仿真结果表明,BSRM利用多支持向量机所建立的非参数模型高效且准确,采用此优化方法设计的BSRM转矩脉动小、悬浮力大、绕组间互感小。     

基于转矩分配函数的开关磁阻电机的控制

转矩脉动较大是开关磁阻电机(SRM)的主要缺点,为了减小转矩脉动,提高电机性能,将转矩分配策略应用到电机中,能有效抑制转矩脉动。但由于开关磁阻电机的非线性,使得设计转矩分配函数变得很困难,传统的线性函数虽然简单,但无法体现开关磁阻电机的非线性。虽然非线性正弦函数的提出使得转矩性能得到了提高,但在换相区的效果还是不尽理想。为了解决这个问题,文中提出一种滞环补偿性转矩分配函数,仿真证明了该方法的有效性。     

基于转矩逆模型的SRM转矩脉动抑制研究

开关磁阻电机转矩逆模型的精度对于采用电流控制方式实现转矩控制的系统有很大的影响,文中采用经细菌群体趋药性算法优化后的最小二乘支持向量机建立开关磁阻电机的转矩逆模型,获得电流-转矩-角度特性;进而结合转矩分配函数和电流控制环构SRM转矩控制系统。通过仿真实验表明,该转矩逆模型准确地反映了电机的电流-转矩-角度特性,提高了开关磁阻电机控制系统中电流控制环的精度,并对该系统转矩脉动的抑制有重要作用。     

一种开关磁阻电机模糊PI的直接瞬时转矩控制

噪音是开关磁阻电机应用中的一大难题。针对开关磁阻电机运行过程中转矩脉动较大的问题,采用有限元计算方法所得到的电机模型,在MATLAB中进行开关磁阻电机模糊PI直接瞬时转矩控制的仿真实验。采用Ansoft电磁场仿真软件,搭建了三相4/6开关磁阻电机,并将得到的磁链数据导入MATLAB电机模型中。随后,利用该模型搭建模糊PI直接瞬时转矩控制的Simulink仿真实验平台。实验结果发现,系统在0.01 s时开始响应,转矩浮动在0.05~0.1 Nom之间。该结果表明,将有限元得到的电机模型应用到模糊PI直接瞬时转矩控制的仿真实验中时,可以提高系统响应,并有效抑制转矩脉动。     

基于BP神经网络的开关磁阻电机直接转矩控制建模与仿真

开关磁阻电机具有特殊的双凸极结构,导致其运行时会产生严重的转矩脉动,直接转矩控制可显著降低转矩脉动。但由于磁路的严重饱和,传统方法利用公式计算转矩过程非常复杂,提出一种基于BP神经网络来预测开关磁阻电机转矩,进而进行直接转矩控制的策略。通过有限元仿真得到训练数据经离线训练之后,即可得到输入量到转矩的非线性映射,该控制方法利用BP神经网络泛化、逼近能力强的优点,省去了复杂的转矩计算,同时可以对转矩脉动进行抑制。仿真和实验结果表明,该方法响应速度快,控制精度高。     

改进萤火虫算法在雷达伺服电机控制中的应用北大核心CSCD

由于开关磁阻电机(SRM)特殊的双凸极结构,在运行过程中会产生较大的转矩脉动,文中考虑开关角对SRM转矩脉动的影响,在转矩分配函数控制方法的基础之上,采用改进人工萤火虫算法对SRM开关角进行优化,设计一种基于改进萤火虫算法的转矩分配函数控制方法。该方法以铜耗与转矩脉动率作为优化目标,利用改进萤火虫算法的寻优能力,对开关角进行优化。仿真实验表明:该方法在工况1000 r/min下,相较于传统转矩分配函数控制策略,转矩脉动率减小了5.3%,在2000 r/min下,减小了5.23%。     

基于DSP的电动汽车双轮驱动系统设计

轮式驱动电动汽车采用多个轮毂电机独立驱动车辆-是未来电动车发展的一个重要的方向;开关磁阻电机不仅结构简单、运行可靠、制造成本低,而且调速范围宽、效率高-将其作为纯电动汽车驱动源具有优越性。本文以三相(16/12)极外转子开关型磁阻电机为基础,设计一种以TI公司生产的TMS320F28335 DSP控制芯片为核心的电动汽车双轮驱动系统。同时基于该控制系统,用实验法优化了前述开关磁阻电机的开通角和关断角,得出相电流与电磁转矩之间的关系,以实现通过分配双电机的相电流达到电机转矩的协调控制,从而实现电子差速的目的。     

单绕组磁悬浮开关磁阻电机结构优化设计

针对单绕组磁悬浮开关磁阻电机结构参数的优化问题,提出了基于相关向量机与混合粒子群优化的方法。通过有限元分析计算了电机悬浮力和转矩与结构参数的关系,构建基于相关向量机非参数模型。以电机平均悬浮力和平均转矩最大输出为优化目标,采用混合粒子群优化算法获取最优结构参数,通过对比仿真实验说明了该算法的准确性与优越性,电机性能得到明显提升。     

Novel Switched Reluctance Machine Configuration With Higher Number of Rotor Poles Than Stator Poles: Concept to Implementation

There is a great demand for efficient, quiet, reliable, and cost-effective motor drives for propulsion systems in hybrid and plug-in hybrid electric vehicles. Owing to a rigid structure and the absence of magnetic source on the rotor, a switched reluctance machine (SRM) is inherently robust and cost effective. In spite of these advantages, several challenges in the control of this machine remain an issue, including high levels of torque ripple, acoustic noise, and a relatively low torque density. This paper presents a new family of SRMs which have higher number of rotor poles than stator poles. Using a newly defined pole design formula, several novel combinations of the stator–rotor poles have been proposed. From the simulation and experimental analysis of a prototype 6/10 configuration, it has been observed that this machine produces higher torque per unit volume and comparable torque ripple when compared to a conventional 6/4 SRM with similar number of phases and constraints in volume. The results presented in this paper make this family of machines a strong contender for survivable high-performance applications for automotive propulsion systems. The simulation and experimental results for the prototype 6/10 configuration have been presented and compared to a conventional 6/4 design for verification.      

Hybrid excitation of SRM for reduction of vibration and acoustic noise

The inherent simplicity, ruggedness, and low cost of a switched reluctance motor (SRM) makes it a viable candidate for various general-purpose adjustable-speed applications such as industrial and home appliances. The primary disadvantage of an SRM is the vibration and acoustic noise compared with that of conventional machines. The main source of vibration in the SR drive is generated by rapid change of radial magnetic force when phase current is extinguished during commutation action. In this paper, a hybrid excitation method with C-dump inverter is proposed to reduce vibration and acoustic noise in the SR drive. The hybrid excitation has two-phase excitation by long dwell angle as well as conventional one-phase excitation. The vibration and acoustic noise are reduced because the scheme reduces abrupt change of excitation level by distributed and balanced excitation.     

Torque ripple minimization in switched reluctance motor drives byPWM current control

Higher torque ripple is one of the few drawbacks of switched reluctance motor (SRM) drives which otherwise possess excellent characteristics for applications in many commercial drives. This paper begins with an extensive review of torque ripple reduction methods that appear in the literature and then presents a new strategy of PWM current control for smooth operation of the drive. This method includes a current control strategy during commutation when torque ripple minimization is of utmost importance     

Control of switched reluctance motor torque for force controlapplications

The paper presents a method for controlling switched reluctance motor (SRM) torque for force control applications. SRMs are used in AdeptOne robots, and the authors perform experiments with two robots, controlled in coordination, in grasping and manipulation of various objects. The object and robot parameters are not exactly known, and adaptive methods are used to control the overall system. These methods are model-based control techniques which require high bandwidth torque control. This requirement is typical for high precision mechanisms. SRM characteristics are very nonlinear. In particular the torque ripple, friction, and the torque versus position and current relationships were analyzed in the context mentioned above, and specifically, for force control applications. The proposed method is based on a new commutation algorithm and a measured torque versus position and current relationship, used to smooth the SRM's torque ripple, hence generating a torque output nearly independent of position. Furthermore, the internal friction is estimated on-line, and compensated for. This renders a high accuracy torque tracking. The torque control method is based on feedback from the motor angular velocity, motor angle, armature current, and feedforward for friction compensation and cancellation of nonlinear effects. The method has been tested experimentally on Adept motors and the results were very encouraging. The method has been also used for adaptive control of two coordinated Adept robots     

Variable structure control of an SRM drive

The applications of a variable-structure system (VSS) to the control of a switched reluctance motor (SRM) drive is presented. After reviewing the operation of an SRM drive, a VSS-based scheme is formulated to control the drive speed. The scheme is then designed and tested by simulation. The results show that the VSS control is effective in reducing the torque ripple of the motor, compensating for the nonlinear torque characteristics, and making the drive insensitive to parameter variations and disturbances     

A current modulation scheme for direct torque control of switched reluctance motor using fuzzy logic

The paper addresses a fundamental control issue in switched reluctance motor (SRM) drives — the torque ripples. Normally, torque ripple minimization is achieved by using a look-up tables, i.e., the look-up tables uses stored magnetic characteristics to provide the reference current, on-angle, and off-angle for a given torque. A number of techniques for the generation of reference current profiles that minimize the torque ripples have also been suggested in the past. But due to highly nonlinear characteristics of the SRM, all these schemes are not fully successful. Moreover, their performance depends greatly on the accuracy of the magnetic characteristics measurements of the motor on which most of these algorithms work. Our work is primarily motivated to modulate the reference phase current pattern with the aid of fuzzy logic which is well suited to compensate for the nonlinearities of the system, so that the torque ripples are further suppressed. Performance of the proposed strategy is verified by computer simulation.     

Minimization of torque ripple in SRM drives

The torque pulsations in switched reluctance motors (SRMs) are relatively higher compared to sinusoidal machines due to the doubly salient structure of the motor. The magnetization pattern of the individual phases together with the T-i-&thetas; characteristics of the motor dictate the amount of torque ripple during operation. Both machine design and electronic control approaches have been used to minimize the torque ripple in SRMs. This paper presents an extensive review of the origin of torque ripple and the approaches adopted over the past decade to minimize the torque ripple. A hybrid torque-ripple-minimizing controller that incorporates the attractive features of some of the techniques developed in the past decade is presented along with simulation and experimental results     

Fault-tolerant switched reluctance motor drive using adaptive fuzzy logic controller

An adaptive fuzzy controller has been designed to develop a high-performance fault-tolerant switched reluctance motor (SRM) drive. The fuzzy controller continuously adapts its properties to regulate the machine torque as desired by the drive system even under fault conditions. The adaptation of the fuzzy membership functions results in extended conduction period and increased peak current of the healthy phases to deliver the commanded torque, as much as possible. The adaptive fuzzy controller provides smooth torque output with minimum ripple, even under fault conditions, yielding a high-performance SRM drive with fault-tolerant capability.     

On torque ripple reduction in current-fed switched reluctancemotors

This paper addresses a basic control issue in switched reluctance motor (SRM) drives-the production of a ripple-free torque. Simple and largely model-independent conventional supply waveforms are not able to satisfy this requirement. The goal of this paper is to improve SRM dynamical performance by compensating for motor nonlinearities, while maintaining the robustness of conventional methods. The method is based on a complete parameterization of position-dependent voltage and current profiles in ripple-free operation, and on a waveform optimization to minimize power supply requirements. Furthermore, model uncertainties are included to show that the proposed strategy consistently outperforms the conventional policy. Experimental data verifying the analytical approach are included