Synchronized PWM scheme for dual inverter-fed drives with zero common-mode voltages

Novel method of direct synchronized pulsewidth modulation is applied for control of a dual inverter-fed open-end winding induction motor drive with zero common-mode voltages. New strategy and algorithms of synchronized PWM provide symmetry of the phase voltage of the system during the whole control range including the zone of overmodulation. Spectra of the phase voltage do not contain even harmonics and sub-harmonics (combined harmonics), which is especially important for the drive systems with increased power rating. Simulations gave the behaviour of dual inverter-fed system with the proposed synchronized PWM scheme.