Field reconstruction method applied for harmonic voltage mitigation in salient pole synchronous generators

Abstract

Small synchronous generators may present an output voltage with a relatively high harmonic distortion. It comes from the fact that the flux density distribution along the air gap is not a pure sinusoidal waveform. In this paper the Field Reconstruction Method (FRM) is used as a tool for search the optimal field current excitation in order to achieve a flux distribution closer to sinusoidal. FRM is used as surrogate the Finite Element Technique due its high computational efficiency. A commercial machine is modeled and then a routine is developed to modify the current profile of field excitation in attempt to reduce the Total Harmonic Distortion (THD) in the output voltage waveform. The simulation results showed a voltage profile improvement.