An interconnected adaptive observer for flying capacitor multilevel converters

Abstract

A nonlinear adaptive observer for flying capacitor converters is proposed. The observer estimates simultaneously the capacitor voltages and the load resistance, which adds robustness and improves estimation when system parameters are uncertain. Proposed scheme takes advantage of the converter structure to represent the system as a set of n interconnected subsystems, which allows to overcome the unobservable condition of the original system.This observer can be used to replace the voltage sensors needed to control and monitoring the capacitor voltages. Experimental data is used to validate and evaluate the performance of the proposed scheme.