Closed Loop Control of Multi Level Inverter Tied with 415 V AC Source Using SV-PWM for Renewable Energy

Abstract

In this work, 415 V AC source is interfaced with three-level diode clamped inverter in which renewable energy source is used as a DC source, solar energy is used which is most popular renewable energy source. The obtained DC from the solar irradiation is fed to MPPT (Maximum Power Point Tracking) to utilize voltage at maximum power (DC). The perturb and observe technique is used in this work to track voltage at maximum power. The obtained DC is given to multilevel inverter to convert it into AC by making inverter switches (IGBTs) ON and OFF periodically. To make the switches ON and OFF the space vector pulse width modulation (SV-PWM) technique is used and by using PI controller and PLL (Phase Locked Loop) the close loop system is obtained by interfacing with 415 V AC which is also known as grid tied system. Without a filter, the %THD of line voltage is 30.94% and with the incorporation of filter in the system the %THD of line voltage drastically reduces to 5.39%. The modelling of the entire system is performed through MATLAB/Simulink in this work. The paper also presents the comparison of the results of line voltages for the proposed system with sinusoidal pulse width modulation (SPWM) and SV-PWM techniques.

Keywords: Solar energy, MPPT, three-level diode clamped inverter, gate pulse, SV-PWM