Design Of SRM Integrated Power Converter For Vehicle And Research On Torque Ripple Suppression

Under the "double carbon" national strategic goal of carbon peak and carbon neutral,electric vehicles with electric energy as the core have become the most attractive means of transportation,however,efficient,energy-saving,and highly integrated motor drive systems have become a research hotspot in recent years.Switched reluctance motor has become the most promising automotive motor due to its simple structure,reliable operation,no need for permanent magnets,and high starting torque.However,the switched reluctance motor drive system has a single function,low power density,and the motor has a lot of noise and torque pulsation during operation,which limits its application in electric vehicles.In this paper,the structure of power converter and motor control strategy are optimized to improve power density of electric vehicle system and reduce motor torque pulsation.A switched reluctance motor integrated power converter for electric vehicles is proposed for the problems of low power density and single function of conventional power converters.The integrated converter adds only the front-end circuit to the conventional asymmetrical half-bridge circuit,allowing the motor to operate in drive mode,feed-back braking mode and charging mode.In the boost mode,the boost capacitor is used to increase the bus voltage and effectively improve the drive and braking performance of the switched reluctance motor.In the braking mode,the switching devices are controlled to form a Buck circuit to feed the braking energy back to the battery.In charging mode,the multiplexing of some power devices enables charging with power factor correction.The formulae for calculating the boost capacitance and inductance in the front-end circuit are also derived.This integrated power converter enables functional integration and increases the power density of the system.In order to further suppress torque ripple,based on the control principle of traditional torque distribution function,an improved torque online compensation control strategy is proposed based on the integrated power converter for the problem that the shape of traditional torque distribution function is fixed and it is difficult to match the speed change.This strategy allows the motor to automatically compensate for single-phase torque during operation,so that the total torque remains essentially constant.Subsequently,to address the problem of generating negative torque at high speed with the online compensation control strategy,a self-optimizing control strategy for the phase change zone is proposed,which minimizes torque pulsation by detecting the phase current,calculating the phase torque,and adjusting the opening and closing angles of the phase change zone in real time.A simulation model was built in Matlab/Simulink to verify the effectiveness of the integrated power converter and the improved control strategy.An experimental platform has been built,and motor operation experiments and battery charging experiments have been conducted to verify the feasibility of the scheme.