A Decentralized Controller Architecture for a Cascaded H-Bridge Multilevel Converter

Despite its inherently modular hardware structure, the control system of most cascaded H-bridge converters is usually highly centralized and relies on a high-bandwidth intraconverter communication system to transmit time critical control signals to the module controllers. In contrast, this paper presents a decentralized control strategy for a modular cascaded converter, where each module controller determines its own switching actions based on local sensors, a local current regulator, and a local modulator. The system achieves the same performance as an optimized centralized control system while only requiring a low intraconverter communication bandwidth.