Analysis and Calculation of No-Load EFM Waveform for Powerformer

The field circuit coupling time-stepping FEM is proposed to calculate the no-load EMF waveform of salient pole machine, according to the Powerformer prototype, the no-load EFM waveform of Powerformer is calculated, and the effects of different damper windings constraints are considered during calculation, and then the results are compared with the experimental value. It shows that different constraints on damper winding produce different harmonic content in no-load EMF waveform of Powerformer, and the sine distortion rate also changes in some extent, these changes need to be considered in accurate calculation.