A Hybrid PWM Technique for SMES Integrated Solar PV Based Grid-Tied Transformerless Inverters

This paper introduces a hybrid pulse width modulation (PWM) technique to enhance the efficiency and effectiveness of a grid-feeding superconducting magnetic energy storage (SMES)-based transformerless H6 inverter system. The system is designed to interface solar photovoltaic (PV) power with a low to medium-voltage grid. The presented hybrid PWM technique aims to suppress the total harmonic distortion (THD) of the output voltage of the H6 transformerless inverter. A new carrier signal and a new modulating signal based on fundamental sinusoidal and triangle waves are utilized to model the hybrid PWM technique. The proposed hybrid PWM technique is more efficient and has lower leakage current during energy conversion than traditional bipolar PWM, unipolar PWM, and numerous other well-known PWM techniques. The total system is simulated in the MATLAB/Simulink and PLECS environments to verify the feasibility of the proposed PWM strategy. A 1 kW laboratory-scale prototype based on an H6 transformerless inverter was also built and tested with the proposed PWM technique to prove the effectiveness of the whole system.