Current Balancing Control Methods Using Advanced Carrier-Based Modulation for Five-Level Current Source Rectifiers

In an ideal ac-dc five-level current source multilevel converter, the dc current is equally divided between the two converters connected in parallel. However, current imbalances occur due to the nonidealities of the system, making the current balancing control to improve the multilevel converter performance. This article proposes two different methods for dc current balancing control for a five-level current source rectifier using an advanced carrier-based modulation strategy implemented through three different modulation patterns. A 6-kW prototype is constructed to demonstrate the current balancing control and a comparison among the methods is presented.