The Simulation And Research Of Speed Control Algorithm For SRM

SRM (Switched Reluctance Motor) control system has been the focus of intensive research efforts because of the advantages of flexible control strategy, simple structure, high reliability and excellent electric characteristics. But its greater torque ripple and noise problems restrict its application in some field. So it is necessary to study the speed control algorithm to reduce torque ripple for SRM.In this dissertation, at first, the working principle and adjustable-speed characteristics of SRM is researched on the basis of its basic electromagnetic laws.And then the advantages and disadvantages of traditional control methods,such as current chopping control, angle position control and voltage PWM control, are introducted. At last, the current domestic and international methods of reducing the torque ripple are introduced. Connection with the actual conditions of the relevant laboratory, one key of the dissertation is to optimize SRM's turn-on and turn-off angles.Based on the optimal control of flux-linkage, a simple controller which the optimal firing angles is determined on-line is proposed. It can reduce the torque ripple of SRM and also have good static and dynamic response.In addition, in the traditional control methods for SRM, it is required to use different control strategies at different speed, so it is very complex. It is also through indirect control of current to achieve the control of torque. And the torque is not directly controlled. In induction motors, DTC (Direct Torque Control) which control torque directly has been applied in wide range. Drawing from the induction motor direct torque control, DTC used in SRM is researched in this dissertation. First of all, an expression of instantaneous torque is deduced from elementary function. And then, select six effective voltage vectors to get the corresponding voltage vector sheet. Finally, set up the DTC simulation model of SRM in MATLAB.The simulation results show that stator flux trajectory is a circular and torque ripple is smaller than traditional control methods.Finally, developt the digital controller of the SRM based on DSP and CPLD and study the performances for SRM through the experimental system.