Comparison and Simulation of the Level-Shifted and Phase-Shifted Modulation for a Five-Level Converter for Integration of Renewable Sources

Abstract

Two H-bridge converters are cascade-connected in order to extend the power rating of grid-connected converters. This structure is known as a Cascaded H-Bridge converter. A cascaded H-bridge multilevel converter is introduced in this paper with a detailed discussion about the PI controller based closed-loop control system for the Static Var Compensator (STATCOM) application. This research work incorporates both phase shifted and level shifted multi-carrier based Pulse Width Modulation (PWM) with comprehensive comparisons. Simulation results are presented accordingly to manifest the efficacy and productivity of the proposed model for grid-connected multilevel converters. The benefits of this model are the simplicity of the control, modulation techniques and the quick response to the reactive power adjustment by adjusting the DC bus voltage. The performance of the Cascaded H-Bridge Converter (CHB) model is tested in MATLAB Simulink.