Estimation of flying capacitors voltages in multicell converters

Flying Capacitor Multicell (FCM) converters are very interesting alternative for medium voltage and high power applications. The main reason is increase in the number of output voltage levels and its apparent frequency. Balancing of flying capacitors voltages is an important constraint to proper performance of FCM converters. So, observation of these flying capacitors voltages for using in active control is valuable where using voltage sensors results in increasing cost and size of the converter. This paper presents a new strategy to estimate flying capacitors voltages of FCM converters. The proposed strategy is based on discrete time model of converter. So, advantage of the proposed strategy is its simplicity which is effective for real time implementation. The circuit is simulated using PSCAD/EMTDC software and simulation results are presented to validate the effectiveness of the proposed estimation strategy to observe the flying capacitors voltages.