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     

Power Smoothing Using a Flywheel Driven by a Switched Reluctance Machine

A control system for power smoothing using a switched reluctance machine (SRM) driving a flywheel is presented in this paper. Power smoothing is achieved by controlling the SRM to operate as a motor/generator, storing or retrieving energy from a rotating flywheel. In order to increase the rotational energy stored in the flywheel, the SRM operates at high rotational speed, and the machine phase current is controlled using single-pulse mode. To control the SRM output power, a two-dimensional lookup table is used to store the switching angles. The control strategies proposed in this paper have been experimentally implemented in a 2.5-kW prototype based on an 8/6 SRM. Experimental results are presented and discussed.     

Inductance model-based sensorless control of the switched reluctance motor drive at low speed

A sensorless control scheme for the switched reluctance motor (SRM) drive at low speed is presented in this paper. The incremental inductance of each active phase is estimated using the terminal measurement of this phase. The estimated phase incremental inductance is compared to an analytical model, which represents the functional relationships between the phase incremental inductance, phase current, and rotor position, to estimate the rotor position. The presented sensorless control scheme requires neither extra hardware nor huge memory space for implementation. It can provide accurate rotor position information even as the magnetic characteristics of the SRM change due to aging. Combined with other inductance model-based sensorless control techniques, the proposed method can be used to develop an inductance model-based sensorless control scheme to run the SRM from standstill to high-speed. Simulation and experimental results are presented to verify the proposed scheme.     

A current-controlled quasi-resonant converter forswitched-reluctance motor

A current-controlled quasi-resonant power converter suitable for switched-reluctance motor (SRM) feeding is presented. The converter operation is analyzed and its characteristics are determined in terms of the system parameters. The converter control strategy is studied for different operating conditions. Current control operation is considered and discussed. Theoretical predictions are verified and validated by experimental results obtained with a prototype SRM drive     

Computer simulation and analysis of a new polyphase multipole motordrive

A new configuration for a high-power-density, high-efficiency polyphase multipole permanent magnet motor and its control system are presented. The mathematical model and simulation for this motor drive are presented in detail. The motor is essentially a kind of brushless DC motor with a novel arrangement of its magnet and winding. The control system is virtually a dual closed-loop system with a current controller as the inner loop and a speed controller as the outer loop. State-space equations are used for the mathematical model of the motor, and real-time simulation is applied for the controller and switching devices. The simulation results are verified with the experimental results and shown to be very satisfactory     

基于MATLAB的开关磁阻电机非线性模型仿真研究

在分析开关磁阻电机(SRM)数学模型的基础上,利用MATLAB-SIMULINK环境下的基本模块,采用模块化设计思想,搭建了开关磁阻电机控制系统中功能独立的子模块,如电机本体模块、速度控制模块、电流控制模块、转角选择模块等,利用这些通用的子模块搭建SRM控制系统的仿真模型。仿真结果证明了该建模方法的合理性和有效性。     

开关磁阻电机全数字控制系统中FPGA的应用

提出了基于数字信号处理器（DSP）和现场可编程门阵列（FPGA）的开关磁阻电动机全数字控制系统,对DSP和FPGA的功能进行了分配。根据开关磁阻电动机的驱动要求,分析控制逻辑,由FPGA实现了电流斩波、角度位置和PWM电压斩波相结合的控制方案。仿真结果表明,设计的开关磁阻电动机调速系统具有高效、实时、动态性能好等优点。     

A geometry based simplified analytical model of switched reluctance machines for real-time controller implementation

A geometry based simplified analytical model that decouples the current and position effect on flux and torque in the switched reluctance motor (SRM) drives is presented in this paper. This model gives a direct relation between phase current and torque accounting for the high degree of nonlinearity of the machine. A simple flux model and its inverse relationship have been developed to meet the diverse requirements of controller design. The paper emphasizes and demonstrates the importance of these relationships for real time controller implementation of high performance SRM drives.     

Dynamic Modeling, Experimental Characterization, and Verification for SRM Operation With Simultaneous Two-Phase Excitation

Dynamic modeling of switched reluctance motors (SRMs) is usually done on a per-phase basis. However, in most applications, SRMs are used with simultaneous excitation of more than one phase. Thus, a model accounting for mutual coupling in the presence of magnetic saturation is needed to predict and optimize their performance in terms of efficiency and torque ripple. This paper presents a dynamic two-phase excitation model of the SRM. Motor symmetry is used to reduce the amount of flux linkage data needed for the model. An experimental procedure to obtain the flux linkage data is described. Measured flux linkage data for the 8/6 SRM are also included. Details of the simulation model and comparison with experimental waveforms along with their implications for performance prediction are presented.     

Modeling faulted switched reluctance motors using evolutionaryneural networks

This paper examines the feasibility of using artificial neural networks (ANNs) and evolutionary algorithms (EAs) to develop discrete time dynamic models for fault-free and faulted switched reluctance motor (SRM) drive systems. SRMs are capable of functioning despite the presence of faults. Faults impart transient changes to machine inductances that are difficult to model analytically. After this transient period, SRMs are capable of functioning at a reduced level of performance. ANNs are applied for their well-known interpolation capabilities for highly nonlinear systems. A dynamical model for an SRM is constructed by feeding values for state variables back to ANN inputs. EAs are employed for their ability to search complex structural and parameter spaces to find good ANN solutions. Furthermore, the ANN structure and training regimen parameters are searched for using EAs. Finally, an analysis of the search is performed, and the resulting model is presented. The results of using the ANN-EA-based model to predict the performance characteristics of prototype SRM drive motion under normal and abnormal operating conditions are presented and verified by comparison to test data     

A sensorless switched reluctance drive system using a self-inductance estimating technique

This paper proposes a new method for estimating the shaft position of a switched reluctance motor (SRM). The shaft position of the SRM is obtained by on-line estimation of the self-inductances of the motor, and a closed-loop drive system can thus be achieved. The drive system performs well in both the pulse-width-modulated (PWM) region and the single pulse region. The adjustable speed range of the system is from 20 rev/min to 2000 rev/min. In addition, the drive system is automatically started from standstill to a required speed and exhibits good transient and load disturbance responses. The detailed theoretical analysis and several experimental results are presented in the paper. First, the basic principle of the proposed method is explained. The self-inductance estimating technique is derived by using the mathematical model of the SRM. Then, the relationship between the self-inductance and the shaft position of the motor is discussed. Next, a starting technique is presented. It is then shown how a 32-bit microprocessor system is used to estimate the position and speed, speed-loop control, and the generation of three-phase current commands. Several simulated and experimental results validate the theoretical analysis.     

基于dSPACE的开关磁阻电机模糊控制系统

由于开关磁阻电机存在很强的非线性,为了保证调速系统具有较好的动、静态性能,文中设计了一种复合模糊控制器代替比例积分微分PID控制。采用dSPACE实时仿真环境生成控制器C代码。实时系统具有与实际系统的硬件接口,与电机系统直接相连,构成快速控制原型系统,并对控制参数进行了在线调参。实验结果表明,采用dSPACE平台可以快速完成对SRM控制系统的研究和开发,为电气传动控制系统的设计和开发提供了一种新的思路。     

开关磁阻电机功率变换器杂散参数抑制及散热设计

功率变换器是开关磁阻电机调速系统(以下简称SRD)中保证电机可靠稳定运行的关键部件。在大功率功率变换器设计过程中,对电路的杂散参数以及功率器件的散热等问题的处理是功率变换器结构设计的关键。针对电路中的杂散参数,本文在设计功率变换器过程中构建了60KW开关磁阻电机功率变换器逆变回路杂散电感等效分布模型,分析了杂散电感在器件关断过程中的影响。在此基础上,引入低感叠层母线技术,从结构设计与工程运用角度出发对该母线进行分析,理论计算与仿真结果均表明设计方案比传统设计方案更有效地抑制了主回路杂散电感值。针对功率器件的散热问题,提出一种针对SRM负载的功率电路热损耗估算方法。通过损耗计算得出功率变换器主电路中损耗的来源和器件温升变化,对功率变换器的进一步设计改进有重要意义。     

基于Infineon XC2267的电机控制系统设计

在电动汽车的研究当中,驱动电机及其控制系统设计尤为重要,文中基于英飞凌公司的16位微控制器芯片XC2267,设计了电动汽车用永磁同步电机磁场定向矢量控制系统。对控制系统部分硬件电路进行了设计,并在Simulink仿真环境下建立电机控制系统的的仿真模型。仿真结果表明,系统设计合理、电机运行响应快、稳定性好,而且对永磁同步电机实际控制系统具有一定的指导意义。     

Control characteristics of the SRM drives. I. Operation in thelinear region

The control characteristics of switched reluctance motor (SRM) drives are analyzed for operation of the motor in the linear region of its magnetic characteristics. After reviewing the motor operation, the authors consider the current-fed and voltage SRM drives. For both types of drives, the control variables and the related ranges are identified, the relationships between such variables and the average motor torque are calculated, and the torque capability is found. The basic schemes for the speed control of the SRM drives are also formulated     

Analysis and implementation of a real-time predictive currentcontroller for permanent-magnet synchronous servo drives

A real-time current controller for PWM inverter-fed permanent-magnet synchronous motor drives is presented and analyzed. The proposed current control scheme is based on predictive control with a parallel integral loop added to compensate for the inaccuracy of the motor model and for the variations of motor parameters and DC voltage source. The proposed current control scheme is analyzed and its performance is evaluated by computer simulation. An EPROM-based implementation is presented in which calculations and pulsewidth modulation are executed by lookup tables resulting in high-speed operation. The controller performance is evaluated using a prototype l kW PM synchronous servo drive. Experimental results are given and discussed     

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     

Model predictive control of sensorless hybrid stepper motors in auxiliary adjuster for stereotactic frame fixation

A hybrid stepper motor (HSM) can be practically driven by open-loop control, however, it is definitely not enough for the increasing demands on precision control in wide industry applications. In this study, a practical control scheme, consisting of model predictive control (MPC) and extended Kalman filter (EKF), is presented for controlling a sensorless hybrid stepper motor (HSM). Numerical simulations and real-world experiments are conducted to show the performance and effectiveness of the proposed strategy. To extend the practical usage of the presented design, the proposed strategy has been utilized to control an auxiliary adjuster for stereotactic frame fixation system for use in the precise clinical neurosurgery operation.     

Robust speed control of a switched reluctance vector drive usingvariable structure approach

The robust speed control of a switched reluctance vector drive is presented in this paper. An approximate sliding-mode input power controller and another feedforward sliding-mode speed controller are combined with space voltage vector modulation. The resultant drive has rapid and robust speed response. In addition, a switched reluctance motor (SRM) drive incorporating the proposed controller requires only one current sensor and can be implemented in a low-cost 8-bit microcomputer and a few discrete integrated circuits. Furthermore, the controller does not require any offline characterization of the motor or load characteristics and could easily be applied to SRMs with any number of phase windings. A 4 kW four-phase SRM drive is constructed to test the performance of the controller. The results show that a step response from 200 to 1980 RPM needs only 2-3 s, even when driving a high-inertia load, and that the speed error can be controlled below 1%, even under unknown and dynamic loads. It is concluded that modified sliding-made controllers are effective in dealing with the highly-nonlinear characteristics of the SRM drive system