Six-phase motor drive with variable switching frequencies and voltage synchronization of inverters

In this paper, modulation processes have been analyzed in six-phase asymmetrical motor drive on the base of four inverters with discontinuous synchronous modulation. It has been shown, that flexible PWM strategy based on control of switching frequencies of inverters as function of dc voltages allows to improve system performance and to insure voltage waveform symmetries during adjustment range. Simulations validate operation of systems with basic control modes.