Control scheme of hybrid inverters in high power drives

A control method is developed for a AC drive system, built of a parallel interconnection of a GTO primary inverter and a IGBT slave inverter, feeding a large induction motor where torque ripple attenuation is a primary concern. The GTO inverter is the main power supply and the IGBT inverter is used as an active filter to attenuate the current ripple due to the GTO low switching frequency. The proposed master-slave control scheme combines the best features in comparison of the equivalent voltage-source inverter such as low switching losses and fast current-control dynamics. In the paper the performances of the proposed control scheme are illustrated by using simulations.