Multi-inverter and multiphase power electronic installations have additional degrees of freedom for construction of system topology, and for the choice of modulation schemes and algorithms for control of inverters in these systems. It has been shown, that in combined six-phase drives on the basis of two standard inverters and two neutral-point-clamped converters symbiosis of specialized control schemes with algorithms of synchronous space-vector PWM insures elimination of the common-mode voltage and continuous symmetry of voltage waveforms during entire control region for any operating conditions, and for any (integer or fractional) ratio between the switching and fundamental frequencies of converters. MATLAB-simulations illustrate behavior of four-inverter-based six-phase (asymmetrical dual three-phase) drives with basic schemes of synchronized PWM.