Simple modulator with voltage balancing control for the hybrid five-level flying-capacitor based ANPC converter

Abstract

The hybrid flying-capacitor based active-neutral-point-clamped converter is a recent multilevel converter topology with interesting properties such as high quality output voltage and easy extension to achieve a high number of levels with reduced number of power devices. The control of the flying capacitors of the three-phase converter has been previously carried out by an elaborate control technique taking advantage of the large number of redundant switching states. This paper is focused on the introduction of a simple single-phase modulator for the single-phase five-level hybrid flying-capacitor based active-neutral-point-clamped converter. The single-phase modulator can be applied to each phase of a three-phase converter without losing generality. Using this modulation technique, the dc-link capacitors and the floating capacitor voltages are controlled to their desired values. Simulation results show the good performance of the voltage control obtaining simultaneously high quality output voltages and currents.