HARMONIC AND INTERHARMONIC DISTORTION IN CURRENT SOURCE TYPE INVERTER DRIVES

Current source inverter drives are sources of harmonic and non-harmonic distortion in supply systems The non-harmonic components have frequencies that change with motor speed so conventional filters might not be effective in reducing their amplitude. The distortion calculation at the design stage allows preventive actions to minimise the distortion at source by varying d.c. link an/or a.c. motor parameters. The aim of the paper is to discuss the modeling of the supply side current distortion and to analyse the effects of non-ideal supply conditions. The main utilizable models, both analogue and numerical, are discussed and analysed Several laboratory and numerical experiments are reported to compare the different model characteristics and to analyse the current distortion sensitivity to the supply voltage distortion and unbalance.