Generalized Space Vector Pulse Width Modulation Technique for Cascaded Multilevel Inverters

Abstract

In this study, a generalized space vector pulse width modulation (SVPWM) method is proposed for cascaded H-bridge multilevel inverters. An explicit modulation function expression of the generalized SVPWM method is established for a single-stage cascaded inverter. Various continuous SVPWM and discontinuous PWM methods are obtained easily by changing the zero vector distribution coefficient. The generalized SVPWM method for cascaded multilevel inverters is achieved via the carrier phase shift strategy. A simple digital realization method for the generalized SVPWM is also proposed. By using this method, complex trigonometric function calculations, coordinate transformations, space vector selections, and duration time calculations are avoided. Finally, the simulation model and experimental device of the eight cascaded multilevel inverters are built to test the proposed method. The harmonic characteristics of the different modulation method are also analyzed. Simulation and experimental results demonstrate the feasibility and effectiveness of the method.