This paper proposes a new method for measuring capacitor voltages in multilevel flying capacitor (FC) converters that requires only one voltage sensor per phase leg. Multiple dc voltage sensors traditionally used to measure the capacitor voltages are replaced with a single voltage sensor at the ac side of the phase leg. The proposed method is subsequently used to balance the capacitor voltages using only the measured ac voltage. The operation of the proposed measurement and balancing method is independent of the number of the converter levels. Experimental results presented for a five-level FC converter verify effective operation of the proposed method.
I E E E Transactions on Power Electronics, 2017, Vol 32, Issue 10, p. 8115-8123
Voltage measurement; Capacitors; Switches; Voltage control; Pulse width modulation; Frequency measurement; Control systems, DC-AC power conversion, FC multilevel converter, power converter, voltage measurement