Influence of Static Eccentricities on Performance and Control of Dual Three-Phase Permanent Magnet Synchronous Machines

Multiphase electric motor design can enable a reduction of the maximum current per phase to achieve higher torque and power demands. A common configuration is the dual three-phase PMSM with isolated neutral points. There are different dual three-phase winding approaches. One is designing the distributed winding with an electrical phase shift of 30 degree between the two subsystems, which offers additional benefits e.g. regarding torque pulsation. Another option is to separate the two winding systems by dividing the stator into two equal halves and control both winding sets with no electrical phase shift. Distributing every subsystem over one-half of the stator causes an increased sensitivity concerning static eccentricities which leads to a deviation in the coil flux linkage of every subsystem. This contribution compares, based on 2D FEM simulations, the sensitivity of two different dual three-phase winding configurations on static eccentricities regarding output power and airgap forces. In case of the segregated stator winding a feedforward control is proposed to balance the current sharing. As result, a method to parametrize the control based on end-of-line measurements is suggested.