SRM power density improvement utilizing rotor conducting screens and DC-link voltage-boosting for EV applications

This paper studies the power density enhancement of a four-phase switched reluctance motor using rotor conducting screens and dc-link voltage-boosting for electric vehicle applications. The effect of conducting screen thickness and material electrical conductivity on current rise time, developed torque, and output power is studied. Different screen shapes are compared to elicit the optimum screen design by formulating a multi-objective optimization problem based on maximizing the developed torque and efficiency and minimizing added material weight. A double arm common switch converter with dc-link voltage-boosting capacitors is deployed. The boosted voltage provided by the capacitors aids the winding current to rapidly build-up; thus, increasing the motor base-speed, whence power rating. Finite element analysis results confirm the SRM drive's effectiveness in increasing motor base-speed and improving the torque range, hence the power capability of SRMs to be competitive with an equivalent-volume permanent magnet synchronous motor.