Design and Control Optimisation of a Novel Bypass-embedded Multilevel Multicell Inverter for Hybrid Electric Vehicle Drives

A novel bypass-embedded multilevel multicell inverter is proposed with manipulation of bidirectional flow of currents targeting electric motor drives and regenerative braking (battery recharging) for hybrid electric vehicles. To balance switching losses, maximise DC supply utilisations, balance the state of charge, and minimise total harmonic distortions, the inverter control method is optimised by incorporating phase disposition PWM with variable carrier frequency, third harmonic injection, as well as carrier reordering and reduction schemes. The proposed control scheme is investigated on an 11-level inverter for motor drives of a parallel hybrid electric vehicle with regenerative braking capability. The total harmonic distortion is 1.23% for line voltage, and 1.04% for stator current without filtering networks, i.e. a comparable performance to the states of the arts.