Short-circuit current reduction technique for surface mounted PM machines high torque-low speed applications

Permanent magnet synchronous machines present a high short-circuit current that can lead to the destruction of the motor for high rotor inertia, low speed, applications. The authors present a technique that reduces the short-circuit current of one slots per pole and per phase motors without changing the electromechanical performances. It consist in modifying the number of rotor poles and the power supply frequency whereas the stator remains unchanged. In addition, another remarkable result is obtained. The case of 2 slots per pole per phase motors leads to a magnetic decoupling of the stator phases by an adaptation of the winding.