Fuel-Cell Supplied Vehicle Drive with Synchronized Space-Vector Modulation

Analysis of operation of the six-phase traction drives with two isolated DC sources, controlled in accordance with basic schemes of synchronized pulsewidth modulation (PWM), has been performed. The analyzed drive topology uses two three-phase inverters having different DC link voltages. Two basic control schemes for the six-phase drives with synchronized PWM have been investigated: (1) control on the base of power balancing of the DC sources, and (2) PWM control with unequal power of two DC voltage sources. Special attention has been given to analysis of operation of six-phase drives in the zone of over modulation. The spectra of the phase voltage of the six-phase vehicle drives with synchronized PWM do not contain even harmonics and sub-harmonics during the whole control range, which is especially important for the high power/current applications. Simulations give the behavior of the dual-source fed six-phase motor drives with low switching frequencies, controlled in accordance with algorithms of continuous and discontinuous versions of synchronized PWM.