SRM Torque Ripple Minimization Based On Multi-Level Converter

The Switched Reluctance Motor (SRM) has a high torque ripple because of the silent geometry and nonlinear magnetic characteristic. The high torque ripple affects output characteristic of SRM driving system, and it limits the application of SRM in the situation of low speed and steady such as servo drive system. Therefore the research on torque ripple minimization is always a hot and difficult topic of SRM research.Based on the torque sharing function (TSF) arithmetic and current hysteresis arithmetic, the article uses dual-loop control strategy and inner loop is current while outer loop is speed. It researches on three TSF torque control strategies of SRM torque ripple minimization that are separately based on asymmetric bridge converter, four-level converter and modified multi-level converter. Among them, TSF torque control scheme based on modified multi-level converter is research emphasis. Firstly, A nonlinear model of SRM is established using Matlab/Simulink. Secondly, the nonlinear model of SRM basic speed control system is also established. On the base of this, TSF torque control models of a 12/8 poles 3 phases SRM based on asymmetric bridge converter, four-level converter and modified multi-level converter are established when the models of dual-loop control strategies and converters are joined into control system. The simulation results show that the method of TSF torque control scheme based on modified multi-level converter could reduce torque ripple, improve dynamic performance and efficiency through simulation results contrast.The TMS320F2812 digital signal processor (DSP) is selected as the controller of the torque ripple control system in this thesis. By appropriated assigning system resources, the software and hardware of torque ripple control system for switched reluctance drive (SRD) are designed. The basic experiment of speed control system and the contrast experiments of two TSF torque control strategies of SRM torque ripple minimization that are separately based on asymmetric bridge converter and four-level converter are completed.