This manuscript presents short review of schemes, techniques and algorithms of synchronous space-vector pulsewidth modulation (PWM) developed for overmodulation control of voltage source inverters of transformer-based grid-connected photovoltaic (PV) systems. These system topologies are based on dual-inverter or triple-inverter configurations supplied by the corresponding strings of PV panels, and connected specifically with inverter-side windings of power transformer. Algorithms of space-vector PWM, developed and modified for synchronous control of PV inverters with high modulation indices (operating in the zone of overmodulation) insure synchronization and symmetry of voltage waveforms, characterized by improved spectral composition, at the outputs of inverters and at the corresponding windings of multi-winding power transformer.