Modelling and control of a cycloconverter with permanent magnet generator

Abstract

A 6-pulse noncirculating current cycloconverter is used as frequency changer for a high-frequency permanent magnet generator. A high-efficiency, high-speed gas turbine in the power range of 250 kW to 870 kW, drives the generator-converter unit. This system is intended for use in total energy systems or hybrid systems in vehicles and high-speed vessels. The cycloconverter is designed for three-phase 833 Hz to 50 Hz applications. A new vector-control like digital control strategy and a special discrete Fourier filter (DFT), intended for use with a one-phase version of the cycloconverter, are described. Both are implemented in a multi-processor digital controller used for feedback control and pulse-pattern generation. Simulation results and measurements of a laboratory one-phase version of the converter and a dummy-generator, using this digital control strategy and DFT, are given.