Active power filtering by a flying-capacitor multilevel inverter with capacitor voltage balance

A new control strategy is developed for a four-level flying capacitor multilevel inverter to function as an active power filter (APF). This employs space vector modulation (SVM) scheme. However inverter switching vectors and sequences are determined according to the swings of capacitor voltage values at each level. A modified predictive current control law is developed This takes into account the derivative of the reference current in order to improve the performance of the conditioner when reference current changes quickly. Simulation study has shown that the proposed scheme leads to high performance harmonic current compensation for both steady and transient state operations and capacitor voltages at all levels are well balanced.