A novel permanent magnet motor with doubly salient structure

A new type of doubly salient machine is presented in which the field excitation is provided by nonrotating permanent magnets. This doubly salient permanent magnet (DSPM) motor is shown to be kindred to square waveform permanent magnet brushless DC motors. Linear and nonlinear analyses are made to investigate the characteristics of this new type of PM motor. A prototype DSPM motor is designed and comparisons made between this new type of motor and the induction motor. It is shown that by fully exploiting modern high energy PM material and the doubly salient structure, the DSPM motor can offer superior performance over existing motors in terms of efficiency, torque density, torque-to-current ratio, torque-to-inertia ratio etc., while retaining a simple structure amenable to automated manufacture