Seven-level reduced flying capacitor inverter with improved harmonic distortion using hybrid phase-shifted carrier phase-disposition PWM

This paper proposes a simple modulation technique and a hybrid carrier-based PWM named as phase-shifted carrier phase-disposition PWM (PSC-PD-PWM) to reduce the switching states and the overall switching frequency of the state-of-art multiceli inverter. By doing so, higher number of output phase voltage levels can be synthesized with the number of flying capacitors and power semiconductor switches significantly reduced. Hence, a lower cost and lighter weight of reduced flying capacitor inverter (RFCI) is achieved as compared to the classical multilevel flying capacitor inverter (MFCI) based on phase-shifted carrier PWM (PSC-PWM). On top ofthat, the total harmonic distortion (THD) performance is found to be improved in RFCI with the proposed hybrid PSC-PD-PWM especially for the synthesized output line-to-line voltages. Comparative studies of MFCI and RFCI are discussed in this paper and highlighted the improvements made. In addition to that, the performance of the proposed RFCI with PSC-PD-PWM is evaluated under dynamic conditions. Results have proven the feasibility of the RFCI concepts with the proposed hybrid PSC-PD-PWM.