Electromagnetic Analysis of Rotating Permanent Magnet Exciters for Hydroelectric Generators

Abstract

The purpose of this project is to analyse different design possibilities for a rotating permanent magnet exciter for a hydroelectric generator. This is done through development of design models for optimizing suitable solutions. By use of Matlab/Simulink, COMSOL Multiphysics and ACE, the dynamics and the performance of the design is investigated. The aim is to have a robust system with low torque ripple absorbed by the exciter. It is shown that the six phase rectification solution has lower torque ripple for normal delay angles of the thyristor bridge compared to the three phase solution. For further development to try to reduce the torque ripple even more, one should optimize (reduce) the self and mutual inductances of the exciter rotor windings. A reduction of the parasitic magnetic energy storage in the system will reduce the torque ripple drastically.