Comparative Study on Line-Start Permanent Magnet Synchronous Machines with Different Rotor Structures

Compared with squirrel-cage induction machines, line-start permanent magnet machines have high efficiency and high power factor because they exhibit two torque components: the permanent magnet torque and the reluctance torque. Though the stator of permanent magnet motor is same as the induction motor, numerous configurations are possible in term of the ways permanent magnet is placed in the rotor. In order to find the optimized structure, line-start permanent magnet synchronous machines with different rotor structures will be comparatively studied in terms of dynamics and steady state performance and transient process with finite element method. In this paper, the results for straight shape, v-shape and partially v-shape will be presented.