Power control and management of a hybrid PV/hydro-turbine/battery connected with a central multilevel inverter

The renewable energy systems (RESs) are an alternative power generation especially in the microgrids. Solar energy is the most renewable energy available in the world but it has some disadvantages namely intermittent availability (due to the change in the irradiance and temperature). For this reason, PV power generators should be combined with other renewable resources such as hydro or wind turbine generator to improve the reliability of the generation system. In this paper, modeling and simulation of a grid-connected hybrid PV/hydro-turbine/battery system integrated with a central modified multilevel inverter (MLI). The rated of the PV generator is 2 kW at standard test condition (STC), while the rated of the hydro-turbine is about 4.2 kW. The conventional Perturbation and Observation (P&O) algorithm and maximum power point tracker (MPPT) are used to enhance the efficiency of both the PV generator and hydro-turbine system. A DC-DC boost converter is used to regulate the DC-link voltage (e.g. the reference DC voltage is 200 V). The simulation results show that the DC power is closed to the power generated from the hydro-turbine system and the DC-link voltage is stable under the variation of both the irradiance and the water speed due to efficient energy management of the battery.