Studies on electrical stresses in rotating rectifiers for brushless exciters

This study aims to establish an alternative methodology for determination of the main transients on brushless exciters due to transients in the main generator armature. The method consists in calculating, from design data, the parameters of the equivalent circuits of the main generator and the exciter, followed by simulations, with the software PSIM^®, of the worst voltage and current transients in the main generator armature, like single-phase, dual-phase and three-phase short circuits, asynchronous running of the main generator and out of phase synchronizing. In each case the currents and voltages of the rotative diodes were monitored. Simulation and experimental results are compared.