Development and testing midpoint voltage balance algorithms of three-level inverters

Abstract

Nowadays, the use of inverters is increasing inmore and more applications. Environmental awareness is becom-ing a trend, so more and more people install solar energy systemson their houses, which also require the use of inverters. Higherpower levels have led to the emergence of three-level inverterswhich has opened up new challenges, such as the issue of mid-point voltage balancing. This paper discusses voltage balancingand voltage ripple reduction techniques for three-level inverterswith Neutral-Point Clamped (NPC) topology. The balancing isbased on injecting zero-sequence voltage component in carrier-based modulation. The viability of the modulation techniques areverified by computer simulation and then tested on hardware.