Motor side active filter for high power synchronous drive

A novel approach to the parallel connection of VSI, called MSAF (motor side active filter) with predictive control is presented and analysed. It allows to reduce both the power module switching losses and to improve the quality of the motor currents. In particular, the active filtering approach is used in order to compensate the effects, on a synchronous machine, of a voltage source inverter operating with a low switching frequency. The improvement introduced by the proposed solution is an optimized power sharing in a VSI parallel connection. This power sharing is performed in order to allocate the most part of the load current to a VSI operating at a low switching frequency, while a second VSI, operating as an active filter, supplies only a small part of the load current. Simulated and experimental results are described.