Cascaded H-Bridge Multilevel Inverter Topology with High Frequency Galvanic Isolation for Grid Connected PV System
Keywords:Cascaded H-Bridge MLI, MPPT, Flyback Converter, PV Modules, MOSFET Switches, Galvanic Isolation.
Cascaded H-bridge multilevel inverter is a dynamic solution for grid connected PV system. Due to separate
DC link feature DC sources can be replaced by PV module/panel and more precisely voltage is controlled. This can be
achieved by introducing maximum power point tracking (MPPT) in each module .the total power extracted from PV
panels will be maximized and hence the efficiency improves. This paper consist of single phase cascaded H-bridge MLI
topology is proposed for grid connected PV system and each modules is connected to one DC-DC flyback converter to
achieve best MPPT as well as galvanic isolation to improve efficiency. The DC-DC flyback converters are cascaded to
amplify the DC voltage in order to be used for medium and high voltage systems and result output voltage is used as an
input to H-bridge. Two MOSFET are operating in line frequency and two at switching frequency. This proposed model
will reduce switching losses and improve efficiency due to MLI obtain the best MPPT , get isolation at high frequency
eliminating the leakage current ,switching losses and voltage ripple.