A Model-Based Controller for the Cascade Multilevel Converter Used as a Shunt Active Filter

This paper presents a modeling process for the cascade H-bridge three-phase multilevel converter used as a shunt active filter. Based on the proposed mathematical model, a controller is designed to compensate harmonic distortion and reactive power due to a nonlinear load. Simultaneously, the controller guarantees regulation and balance of all capacitor voltages. The idea behind the controller is to allow distortion of the current reference during the transients to guarantee regulation and balance of the capacitors voltages. The results are shown for a cascade H-bridge three-phase five-level converter, however, this approach can be easily extended to higher levels.