APPARATUS AND METHOD FOR CONTROLLING DELTA-CONNECTED CASCADED MULTILEVEL CONVERTER

Embodiments of present disclosure relate to an apparatus and a method for controlling a delta-connected cascaded multilevel converter. The apparatus () for controlling a delta-connected cascaded multilevel converter () comprises: a converter controller () configured to: receive current signals indicating phase currents flowing through respective phase arms of the converter (); determine a harmonic current signal indicating a circulating current of the converter () from the current signals; and generate, based on the determined harmonic current signal and a reference current signal, a harmonic voltage signal to cause an amplitude of the circulating current flowing through the phase arms of the converter () to be a predetermined amplitude.