Study On Torque Ripple Reduction Control Of Three-Phase 12/8 Structure Switched Reluctance Motor

Two new direct torque control strategies are given to reduce the torque ripple of the three-phase 12/8 structure switched reluctance motor(SRM). Firstly, the torque ripple features of the three-phase 12/8 structure SRM are analyzed. Then three operation states of asymmetrical half-bridge power converter are defined, which are switch-on state, switch-off state, and the freewheeling state. In the switch-on state and the switch-off state, a new two-level DITC Strategy is given. And in the three kinds of states, a new three-level DITC Strategy is achieved. Combined with the Matlab/Simulink simulation results of two-level DITC Strategy and two-level DITC Strategy, system commutation processes are analyzed. Matlab/Simulink simulation results for different turn-off angles show that delaying turn-off angles can increase the commutation overlap intervals, and improve the smooth torque output.Matlab/Simulink simulation results for different turn-on angles show that delaying the turn-on angles will decrease the commutation overlap interval, and cause phase currents can not be established in time. Compared with the turn-off angle, the turn-on angle’s effect is more obvious. Furthermore, an experimental platform for a three-phase 12/8 structure SRM prototype is built, including the hardware system and software system. The hardware system mainly includes the TMS320F28335 DSP board, the signal-isolated circuit, the drive circuit, the power converter and the related peripheral circuits. The software system mainly includes the main program, the system initialization subroutine, the ADC7606 initialization subroutine, the LCD12864 initialization subroutine, the e QEP capture initialization subroutine, the DAC8563 initialization subroutine, the SCI initialization subroutine, and the system interrupt initialization subroutine. In the interrupt function subroutine, the timer interrupt function subroutine and the external interrupt function subroutine are designed respectively. The control algorithm subroutine called by the external interrupt function is analyzed as well. Taking a three-phase 12/8 structure SRM as the control object, comparative analysis of experimental results under two-level DITC and three-level DITC are completed. The experimental results indicate that the given torque ripple control strategies can achieve smooth torque output. Finally, the work of this paper is summarized and the work prospect is given.