Study On High-Performance Switched Reluctance Drive Control System

Switched reluctance motor(SRM) takes on the merits such as simple structure, low cost, flexible control, etc. Switched reluctance drive system (SRD) has the advantage that conventional AC or DC drives system may not have, it attracts more and more attention and shows competition in commercial applications. In this dissertation the 0.75KW 4-phase switched reluctance motor is studied. The main aspect of study focuses on the theory of intelligent control system design for SRM.Firstly, this thesis introduces the development of SRM control system design, and then analyzed the principle and mathematical model of SRM. This thesis analyzes PWM control method of SRM and its converter circuit characteristic, and designed the hardware control system based on TMS320F240 DSP controller. The control system includes detector circuit, protection circuit, control and man-machine interface circuit, which makes full use of DSP recourse for high reliability and simplified the construction of system. The linearized simulation model and DSP control software are also introduced.Significant torque ripple, vibration and acoustic noise are the main drawbacks of the SRM to achieve higher performance. Several strategies are shown in this thesis to minimize the torque ripple and achieve the performance. These strategies include DTC control of SRM and a fuzzy-logic-based torque ripple reduction method for switched reluctance motors using a turn-off angle compensator approach. Simulations show that these strategies can reduce the torque ripple. The micro-step control is proposed to reduce the torque ripple and achieve more accurate position ability. Based on the torque-angle characteristic, the phase current is regulated according to the torque star map during commutation. The current of each phase become step waveform and derived vectors are obtained. So the step angle of the motor becomes smaller and the torque more smooth. The simulation and experiment results show that this system not only is feasible, but also is of fine speed and position control ability and has broad developing prospects.Finally, the application of SRM in electrical actuator is discussed.