Three-Level Flying Capacitor Multilevel Topology with Delta-Sigma Modulation

This paper proposes a novel modulation concept for a 3-level flying capacitor multilevel system using an asynchronous delta-sigma modulator (ADSM). The benefits of delta-sigma modulation, including noise shaping, spread-spectrum qualities, and a lower average switching frequency while maintaining the same signal quality as traditional pulse-width modulation (PWM) methods, can be exploited in multilevel power converters. A control circuit is introduced which determines the flying capacitor voltage from the output switching terminal and keeps the flying capacitor at a constant voltage. In this paper, we present the concept of the modulator and the control circuit to control the flying capacitor voltage. We confirm the modulation method by simulations and measurements.