Autonomous Power Management of Series-Parallel Hybrid Microgrid

This paper presents a hybrid topology microgrid formed by a series-parallel arrangement of dispatchable and non-dispatchable distributed generation units (DGs). The proposed hybrid microgrid offers the inherent benefits of a series topology, such as power conversion stages with reduced step-up gain, while still maintains the redundancy offered by a parallel topology. However, existing power regulation control approaches for series and paralleled DGs are contradictory to each other, and therefore cannot be applied to the proposed hybrid microgrid. To address this challenge, a new fully autonomous power management scheme is developed, which ensures proportional power sharing among the paralleled string units, while also satisfies the operational constraints of the non-dispatchable DGs, such as MPPT tracking, reactive power support, and on-demand power curtailment. The performance of the proposed control scheme has been extensively verified in simulation environment for different operating scenarios.