Voltage Balance Control for a Multilevel Interface for Renewable Energy Systems

Abstract

This paper presents a new method to balance the DC link voltages in a 3 level Diode Clamped Rectifier, even in the presence of unbalanced loads which cause a non-zero neutral point current. The method employs an offset which is added to each of the inverter modulation waves. This offset causes a zero sequence voltage which can drive the desired neutral point current whilst maintaining balanced DC link voltages. Simulation and experimental results confirm the method.