Synchronously modulated cascaded neutral-clamped converters for photovoltaic application

The paper presents results of dissemination of a novel method of synchronized pulsewidth modulation (PWM) for control of dual (cascaded) neutral-point-clamped inverters for photovoltaic generation. Basic system topology includes two insulated strings of photovoltaic panels, feeding two cascaded neutral-clamped inverters, connected to grid by a three-phase transformer with the open winding configuration on primary side. Algorithms of synchronized PWM provide in this case continuous phase voltage synchronization. Simulation results present behavior of the systems. Spectral assessment of quality of the phase voltage for the systems with three basic versions of synchronized PWM has been performed.