Decoupled DC-Link Capacitor Voltage Control of DC–AC Multilevel Multileg Converters

This paper studies the coupling between the capacitor voltage control loops of diode-clamped (or functionally equivalent) multilevel multileg (multiphase) dc-ac converters. From a complete model of the plant revealing the coupling, a simple approach consisting in multiplying the vector of control commands by a constant matrix is proposed to decouple the control problem and achieve a better controller performance. Simulation and experimental results are presented to prove the superior performance of the proposed decoupled control.