Digital simulation of power conditioner-machine interaction for electronically commutated DC permanent magnet machines

The electromagnetic interactions between a transistorized chopper-inverter power conditioner and its associated permanent magnet machine is analyzed digitally by an experimentally verified time domain state model. The model is applied to the design of a system based on a ferrite type machine. The impact on the overall system performance of skewing the stator core to reduce the harmonics in the induced machine EMF is determined using this model. The EMF waveforms for zero, half, and one slot pitch skewing are determined by finite element analysis of the fields inside the machine. Furthermore, the impact on the system performance of varying the commutation angle to overcome inductance caused performance limitations is examined for each of the three cases of stator skewing.