Dual reference phase shifted pulse width modulation technique for a N-level inverter based grid connected solar photovoltaic system

摘要

This study presents a control algorithm of a grid tied solar photovoltaic (PV) system using a dual reference phase shifted pulse width modulation technique for a single-phase cascaded N-level inverter. The grid tied inverter consists of several five-level hybrid inverter modules which are connected to the solar PV panels having equal DC voltage magnitudes. The proposed control technique for the multilevel inverter generate the near-sinusoidal current with near-unity power factor to the grid and balance the capacitor voltages across the DC links. The voltage and frequency of the multilevel inverter can be adjusted using closed loop control, such that, the maximum power flow to the grid can be achieved even under varying grid voltage. The performance of the complete system has been verified under different transient states. Experimental results verify the effectiveness of the proposed technique.