Active Capacitor Voltage Balancing Control for Three-Level Flying Capacitor Boost Converter

Abstract

The average-behavior circuit model of three-level flying capacitor boost converter (FCBC) is presented in this paper. The small-signal transfer functions of three-level FCBC are first obtained that are including two control signals as the input signals and including the output voltage and the capacitor voltage as the output signals. Besides, the voltage regulating controller is a proportional-integral (PI-type) controller and the voltage balancing controller is a proportional (P-type) controller. Based on the small-signal analysis of three-level FCBC, the closed-loop transfer functions can be obtained and the controller parameters can be selected as well. All the algorithms are implemented in a Field Programmable Gate Array (FPGA) chip. The simulation and experimental results validate the capacitor voltage balancing capability of the proposed method.