Least-squares estimation of capacitor voltages in flying capacitor multilevel converters

This study presents a scheme to estimate the capacitor voltages in flying capacitors multilevel converters. Proposed scheme is based on the function that links control signals, capacitor voltages and the output voltage. Measuring the output voltage and knowing the switching function applied to each commutation cell, it is possible to compose a set of linear equations from which individual capacitor voltages can be reconstructed. The estimation scheme is based on a least-squares algorithm, and it does not need any system parameter as it does most of the known schemes. The proposed scheme is validated using experimental measurements from a five-level converter prototype.