Novel modulator for the hybrid two-cell flying-capacitor based ANPC converter

Abstract

Among the multilevel converters present in the industry, the hybrid flying-capacitor based active-neutral-point-clamped converter is very recent. It presents good features such as high quality output voltage, high modularity and easy extension to achieve a high number of levels with reduced number of power devices. This paper introduces a simple modulator for the single-phase two-cell hybrid flying-capacitor based active-neutral-point-clamped converter. The modulation technique is based on the determination of a switching sequence formed by two switching states which generate the two nearest voltage levels to the reference phase voltage. Some extra calculations are added to the modulation method to control the dc-link capacitors and the floating capacitor voltages. The computational cost of the modulation technique is low only including simple comparisons and mathematical expressions. Simulation results show the high quality output voltages and currents including the dc voltage control.