Modelling and implementation of cascaded multilevel inverter as solar PV based microinverter using FPGA

In the field of power electronics, multilevel inverter plays a vital role for power quality improvement. The high switching frequency is used to obtain quality output waveform with a minimum amount of ripple content. The high voltage is reached by using voltage source inverter with almost zero harmonics without series connected switching devices. If the voltage level increased, the harmonic content of the output voltage waveform decreases in multistage converter. In this present work, single phase cascaded nine level inverter is designed for low powered microinverter and switching angles are produced by Selective Harmonic Elimination (SHE) technique. Each bridge in cascaded inverter will produce the output at different levels and allowing an overall nine level AC output voltage. Now-a-days, the solar photovoltaic is connected with microinverter is an efficient way of increasing the performance so that the proposed inverter derives an input from single PV module since it is module level inverter and it can provide good regulation for leads up to their rated capacity. The prototype is designed for 80W rating and the control signals are generated and processed using FPGA controller. The proposed inverter is designed and tested experimentally to verify the theoretical explanations and proposed design delivers high efficiency when compared with the conventional inverter at full load.