The Control Design Of Efficiency And Torque Ripple Optimation Of Switched Reluctance Motor

Switched reluctance motors have a simple construction, low cost, and high fault-tolerant features, suitable for electric vehicle applications. Compared to the permanent magnet motors and AC induction motors, switched reluctance motor has not been widely used. The main reason is the switched reluctance motor drive system has low efficiency and high torque ripple. The study of the optimization of SRM efficiency and torque ripple has been highly valued.Firstly, this thesis describes the basic principle and the control models of SRM. The mechanism of the efficiency optimization and the source of the torque ripple optimization are analyzed in the linear inductance model. The formula of the turn-on angle for the optimal efficiency is calculated. A theory to improve the commutation torque increasing the turn-on angle and to control torque ripple by reducing the maximum torque is proposed. On the basis above, the strategy of APC/PWM control segment to optimal the efficiency and torque ripple is adopted. Second, the flux data of 4.2kW high voltage SRM is measured by the DC voltage pulse method. The formula of the actual inductance in the small-inductance is fit and the formula of the optimal turn-on angel is calculated. The look-up table of the torque-angle-current is established, and the maximum torque and the angle position are got. The online adjustment of the maximum torque is used to reduce the maximum torque value. Then, the simulation of the SRD is built by the Matlab/Simulink. Compared with the traditional PWM control strategy, the APC/PWM segment control strategy has a higher turn-on angle, efficiency and lower torque ripple. Finally, the measured platform of the SRD is built. The data of the APC/PWM segment control strategy and the traditional PWM control strategy are compared and analyzed, the efficiency and torque ripple of the SRD are optimized.The simulation and test results show that the APC/PWM segment control strategy is better than the traditional PWM control strategy. In the 0%-50% torque range, the efficiency is improved up to 4.14%, and the torque ripple is reduced by 2.44%. In the 50%-100% torque range, the efficiency is improved up to 2.37%, and the torque ripple is reduced by 2.38%.