New Multicarrier Modulation Scheme for Harmonics Mitigation of T-Type Solar Multilevel Inverter

This paper presents a new low-frequency modulation scheme for the power quality improvement of a T-type multilevel inverter (T-MLI) based solar photovoltaic (SPV) system. The T-type converter is employed for DC-AC conversion, generating five voltage levels with six switches per phase. The new modulation scheme is generated with two different functions i.e., sine and pulse generator, to have a modified carrier wave. This unique modified shape reduces the total harmonics distortion (THD) of the five-level output voltage compared to well-known pulse width modulation (PWM) techniques. The new modulation is used for closed-loop switching of a three-phase multilevel converter with designated maximum power point trackers (MPPT). The unit template control is utilized in this paper to generate reference grid currents. This system feeds active power in variable solar irradiances with enhanced power quality. Simulated results show the effectiveness of the system, and real-time implementation validates its practicability.