Comparative performance analysis of VSI and CSI supply solutions for high power multi-phase synchronous motor drives

In today’s high-power electrical drives using synchronous machines, voltage source inverters (VSI) based on multilevel PWM technology and current source inverters (CSI) based on load commutated operation are the most important alternatives for motor supply (cyclo-converters being confined to very low speed applications). In this paper a comparative performance analysis of the two drive typologies in various multi-phase design configurations is presented. It is highlighted how the performance of the CSI drive could be remarkably improved resorting to motor windings with more than six phases.