Experimental comparisons of space vector neutral point balancingstrategies for three-level topology

The three-level neutral point clamp topology has attracted applications in medium-voltage high-power drive systems in recent years. Since the topology utilizes a neutral point voltage to achieve half bus voltage withstanding of power devices and threelevel output voltage delivery, it is critical to balance the neutral point voltage in occasions of disturbed or even continuous unbalance load conditions. This paper proposes a couple of balancing techniques based on space vector modulation principle and experimentally compares their effectiveness against the existing method.