Algorithms, Schemes and Techniques of Space-Vector Modulation for Dual-Inverter Systems with Symmetrical Multilevel Phase Voltage

Basic schemes of synchronized space-vector-based pulsewidth modulation (PWM) have been applied for control of dual-inverter fed open-end winding motor drive supplied by two dc-sources with non-equal voltages. It has been shown, that algorithms of synchronized PWM provide continuous phase voltage symmetry for any ratio (integral or fractional) between the switching and fundamental frequencies of two inverters, and also for any ratio between voltages of two dc-sources of dual-inverter systems. MATLAB-based simulations illustrate behavior of dual-inverter systems with synchronized PWM. Spectra of multilevel phase voltage of open-end winding drives with both continuous and discontinuous schemes of synchronized PWM do not contain even harmonics and sub-harmonics during the whole control range, including the zone of overmodulation, which is especially important for the medium-power and high-power systems.