Synchronous PWM control of dual neutral-clamped converters for electric vehicle drive

A novel method of synchronized pulsewidth modulation (PWM) has been disseminated for control of dual neutral-point-clamped inverters feeding asymmetrical dual three-phase (six-phase) motor drive with two DC sources. Control algorithms provide in this case elimination of alternating common-mode voltages both in each inverter and in the load. Phase voltages of the drive system are characterised by quarter-wave symmetry during the whole control range including the zone of overmodulation, and its spectra do not contain even harmonics and sub-harmonics. Simulations give the behaviour of dual three-phase system with three versions of synchronized PWM.