An improved power converter for standalone Photovoltaic system

As the availability of solar energy varies widely with time and with different atmospheric condition, the cascaded multilevel inverters generates distorted output ac voltage and current if the generated PV voltages of each PV module are unequal. This paper proposes a novel space vector modulation technique for the single-phase cascaded H-bridge multilevel inverter (CHBMLI) to generate a balanced output voltage even under partial shadow condition of Photovoltaic (PV) module. In this topology each H-bridge cell of CHBMLI is connected to an individual PV module through a buck type DC-DC converter. This topology permits independent control of each PV module to operate them at maximum power point. It also offers other advantage such as lower current ripple compared to standard two-level topologies. The simulink model is developed using simpowersystem and simulink toolbox of MATLAB.