A theoretical and practical consideration of optimised input filter design for a low loss matrix converter

The paper reports the construction and testing of a matrix converter in which novel switching methods are employed to minimise the losses in the switching devices. A mixture of hard and soft commutation is used during each cycle of the output waveform. This permits losses to be reduced to a minimum while waveform quality is enhanced. IGBTs are used as the switching devices and a microcontroller generates the switching waveforms and provides control. The problems associated with input current filtering to comply with existing and possible future European EMC regulations are investigated. The paper compares disturbance voltage results from mathematical theory, computer simulation, and practical measurements from a power level converter under microprocessor control. Possible designs for an input filter to meet the European standards are considered. The relationship between the converter switching frequency and the cost of the input filter is explored