Two-Stage Transformerless BI6-Topology-Based Microinverter

This paper proposes an application for the boost inverter 6 (BI6) topology as a microinverter, leveraging its capability of single-stage boost operation. A front-end DC-DC boost converter is added at the input side of the BI6 to increase the voltage-boosting gain and implement the maximum power point tracking (MPPT) technique. The BI6 is operated with a fixed boosting duty cycle, leaving two control variables in the system: the modulation index of the BI6, controlled by a current controller, and the duty cycle of the front-end boost converter, controlled by the MPPT controller. A MATLAB/Simulink simulation has been carried out to validate the proposed microinverter system.