DESIGN AND PERFORMANCE EVALUATION OF A MEDIUM POWER PM-ASSISTED RELUCTANCE SYNCHRONOUS TRACTION MACHINE USING BONDED PM-SHEETS

This paper describes the optimum design of a permanent-magnet-assisted reluctance rotor of a 110 kW reluctance synchronous traction machine. Previous studies show that the performance of the pure reluctance synchronous machine drive deteriorates fast in the flux-weakening speed region. To address this problem, thin bonded permanent-magnet sheet material is used inside the flux barriers of the reluctance rotor to improve the performance of the drive, especially in the flux-weakening speed region. A design optimization algorithm is implemented to minimize the volume and hence the cost of the permanent-magnet material, subject to voltage and torque constraints. The calculated and measured results show clearly that the performance of the reluctance synchronous traction machine with a minimum amount of permanent-magnet material in the rotor compares favorably with the performance of the conventional induction machine drive at both rated and maximum speeds.