A Two-stage Four-port Inverter for Hybrid Renewable Energy System Integration

This paper presents modeling and controllers design of a two-stage four-port inverter which interfaces with a wind turbine generator, photovoltaic (PV) panel, battery, and the AC load. The small-signal model of the whole system is first derived from the differential equations in the different operation stages. Based on the model, DC and AC side controllers are designed to control the battery voltage and current, DC-link voltage, and inverter output voltage and current, respectively. Matlab/Simulink simulation studies were carried out to testify the designed controllers with the real wind and solar data. The simulation results show that the proposed converter is capable of simultaneously doing maximum power point tracking (MPPT), protecting battery, and maintaining the sinusoidal voltage output with designed controllers. Experimental results further validated the effectiveness of the designed controllers.