Power Management in a Utility Connected Micro-Grid with Multiple Renewable Energy Sources

As an efficient alternative to fossil fuels, renewable energy sources have attained great attention due to their sustainable, cost-effective, and environmentally friendly characteristic. However, as a deficiency, renewable energy sources have low reliability because of their non-deterministic and stochastic generation pattern. The use of hybrid renewable generation systems along with the storage units can mitigate the reliability problem. Hence, in this paper, a grid connected hybrid micro-grid is presented, which includes wind and photovoltaic resources as the primary power sources and a hydrogen storage system (including fuel cell and electrolyzer) as a backup. A new power management strategy is proposed to perform a proper load sharing among the micro-grid units. Hybrid (distributed/central) control method is applied for the realization of the control objectives such as DC bus voltage regulation, power factor control, synchronous grid connection, and power fluctuation suppression. Distributed controllers have the task of fulfilling local control objectives such as MPPT implementation and storage unit control. On the other hand, the central control unit is mainly responsible for power management in the micro-grid. Performance and effectiveness of the proposed power management strategy for the presented micro-grid are verified using a simulation study.