Capacitor and input voltage estimation scheme for Flying Capacitor Multilevel Converters modelled as a Petri Net

Abstract

This paper presents an estimation method for the capacitor and input voltages in Flying Capacitor Multilevel Converters (FCMC). The scheme uses only the output current and voltage measurements. Furthermore, the estimation scheme is represented as a Petri Net, allowing a compact and formal approach to represent the estimation process. This scheme simplifies the needed hardware by using only one voltage sensor, simplifying its associated electronics and communication channels, allowing its real-time implementation in systems with a high number of levels. Simulation and experimental results obtained with a nine-level FCMC current-controlled chopper are presented. The converter control loops use the estimates. Different operating conditions are used to evaluate the system, verifying that the estimation scheme can successfully replace the (n-1) needed voltage sensors with only one.