Investigation of a Circuit Model and a Control Strategy for the Generalized Cascaded Full-Bridge Converter

This brief addresses an overall circuit model to represent a novel generalized cascaded full-bridge (GCF) converter. The synthesis methodology of the GCF converter uses full-bridge sub-modules (SMs) combined with the interleaving and cascading concepts. The time-dependent equations represented in terms of current and voltage magnitudes are obtained. Thus, it is possible to derive a comprehensive control system approach from the model. An improved control strategy provides power balancing while using the circulating current to balance the dc-link voltages and ensuring proper current sharing. A small-scale laboratory prototype of a static synchronous compensator (STATCOM) rated at 2.2 kVA/311 V validates the theoretical assumptions and statements.