Z source inverter application and control for decentralized photovoltaic system

Renewable energy sources and technologies are increasingly gaining popularity in developing countries as their increasing energy demand can be met by the unexplored potential of renewable energy. With help of decentralized system the power can be directly used at local load centers which will ease centralized grid. The Impedance Source Inverter (ZSI) has many unique advantages as compared to normal Voltage Source Inverter (VSI) and is suitable for both centralized and decentralized applications. This paper elaborates the distinguishing feature of ZSI which makes it suitable for isolated and grid integrated applications for a source whose nature is highly intermittent. Operating principle, steady state analysis, different carrier modulation techniques to control shoot-through (ST) states are described. ZSI is able to maintain the constant load bus voltage when connected to a highly intermittent PV panel with help of suitable control technique. Its superiority in decentralized photovoltaic (PV) application is verified with help of MATLAB/Simulink environment. An insight of inter-dependency of semiconductor device voltage stress, boosting factor (B) and modulation index (M) for sinusoidal pulsewidh modulation (SVPWM) control techniques is also presented.