Hybrid Energy Storage System Power Division in MicroGrids Using a Multilevel Power Converter

In this paper, a new power division approach is proposed for a Four-Wires Three-Level Neutral Point Clamped (4W-3L-NPC) inverter used as the unique interface for a Hybrid Energy Storage System (HESS) supplied by a renewable energy system in the context of a Microgrid. The objective of this work is to define the limits of the investigated topology and prove its capacity to manage the power division and power exchange capabilities of a HESS. The proposed power division index is expressed using the DC mean power and AC active power, giving a clearer and simpler insight of the limits which are facilitating the implementation in the final controller. To prove its capability, the investigated approach has been tested in the context of a Microgrid with and without Renewable Energy Sources injection on the DC bus.