Search for optimization of synchronous generator excitation machine by analyzing the rectifier commutation angle

A well known characteristic of a synchronous generator excitation drive is the large commutation overlap of the rotor side rectifier. A large value of the rectifier commutation angle adds an important non-linearity for synchronous generator control applications and increases the energy loss. In this paper, the variation of the commutation angle and the parameters that determine its magnitude are investigated using three types of excitation machine: a salient-pole permanent magnet synchronous machine and salient-pole wound field synchronous machine with and without damper windings. The results show the direct influence of the leakage fluxes and present the contribution of the q-axis damper windings. Experimental tests are presented and discussed. Some ways to optimize the excitation machine are also presented.