Abstract

Modular multilevel inverters have been proposed as a potential replacement for diode-clamped inverters in high-voltage, high-power applications as they can be extended to any number of levels without introducing significantly more complexity to the control system. This study discusses in detail the principle of operation, carrier-based pulse width modulation and a capacitors voltage balancing technique for three-level and five-level modular inverters. The modulation and balancing strategy presented are confirmed by simulations and the results are discussed.