Control of A Modular Scalable SiC-based AC-AC Converter With Small Arm Inductance and DC Capacitance

This paper presents the control of a modular and scalable three-phase AC-to-AC converter that features small and inductance and DC cell capacitance. While the phase-leg output inductor current is controlled by its average value controller, the arm inductor currents are under the peak-current mode control so that the arm inductance can be selected to be very small and voltages of cell capacitor banks within the phase-leg can be balanced within one switching cycle. An interleaving between the pulse width modulation carrier signals of three phases is implemented to reduce the common-mode noise generated by switching the 1.7 kV SiC MOSFETS. One main controller and six phase-leg controllers are utilized to enable the scalability of the control system. Experimental tests validated the proposed control system for the converter.