Self-precharge for single-leg odd-level multilevel converter

Abstract

Flying Capacitor (FC) multilevel pulse width modulated (PWM) converters are an attractive choice due to the natural voltage balancing property. It was previously shown the natural balancing method is falling short for self-precharge of odd-level FC converters. In this paper, a new switching scheme is proposed implementing zero average output voltage during start-up and using a controlled DC-bus voltage rise. The DC-bus rate must depend on the capacitor voltage balancing dynamics. (6 pages)