A new circuit of Modular Multilevel Inverter for grid-connected photovoltaic conversion plants

This study presents a new circuit topology of the Modular Multilevel Converter (MMC) which is deployed for photovoltaic grid applications. In the conventional MMC, two arm inductors are placed in each phase to limit the circulating current. In the proposed topology, the inductors are replaced by a transformer. The proposed circuit gives a 50% reduction of the voltage rating of the power devices and the capacitors in comparison with the conventional MMC. The required dc-link voltage which is fed directly by PV panels is also reduced by half. The paper presents a PWM method to control the solar inverter output voltage. The proposed concept is confirmed through simulation and experimental results.