Generic Predictive Control Algorithm to Eliminate the Common-Mode Voltage in Multilevel Three-Phase Inverters

Abstract

Medium-voltage industrial motor drives have been facing the problem of common-mode voltage(CMV) for the past few decades. Multilevel inverters provide not only better inverter performance but also greater electrical motor utilization. Conventional control of inverters with SVPWM has to limit constraints to accommodate the non-linearity and operational flexibility. The predictive controller can build the cost function to accommodate all possible improvement functions that are preferred over these conventional inverter-driven machines. This paper describes a generic approach to developing a predictive control algorithm for two-, three-, and five-level diode-clamped inverters. This algorithm provided the choice of optimal voltage vector selection in the elimination of the common-mode-voltages in three-phase inverters. The effectiveness of these switching voltage vectors also contributes to the improvement of inverter efficiency and DC-bus utilization. The implementation of this generic algorithm has been verified through simulation and laboratory prototypes.