Analysis of switching loss of an AC fed direct converter for a switched reluctance machine

This paper evaluates switching and conduction losses of a direct AC fed converter for switched reluctance machine drives. The commutation process of the converter employing space vector modulation is analyzed, and the switching losses associated with ldquohardrdquo turn-on and ldquohardrdquo turn-off events are quantified based on experimentally validated device characteristics. It is shown that for a given dc load current, the switching loss varies with the voltage stress across a device, whilst the conduction loss is independent of the input voltage and modulation index. The total converter loss over a fundamental electrical period is obtained by taking the average value of the switching and conduction losses over 60⁰ electrical period.