Executive Summary : | The integration of Electric Vehicle (EV) charging station in hybrid microgrid improves the system performance significantly by reducing the transmission losses as compared to when powered from utility grid, and furthermore, has affective power flow control as well. However, the uncoordinated power flow in hybrid microgrid and also for the uncontrolled power flow to EV charging station leads to inefficient utilization of renewable energy sources connected to the ac subgrid or/and dc subgrid in a hybrid microgrid power system. The control power flow between the ac subgrid and dc subgrid can be achieved by employing interlinking converter (AC/DC or DC/AC bi-directional converter), and the co-ordinated power flow control is managed using droop control scheme employed for individual subgrids and for the interlinking converter. Therefore, with such co-ordinated controlled power flow capability, the two sub-grids could be interfaced using the interlinking converter. In this work, a Triple Active Bridge (TAB) based interlinking converter is proposed to interface the ac subgrid with the dc subgrid and with the EV charging station facility. The TAB has three windings, and the individual windings will be dealing with power exchange from each subgrids and for the power for EV charging station. Therefore, in forming such hybrid system the challenge would be in designing the coordinated droop control scheme for controlling the power flow among the three ports of the TAB converter. The aim of the co-ordinated control would be to manage the power flow and sharing the power according to their availability. Such power flow control will be achieved by controlling the interlinking converter to exchange suitable amount of power between the sub-grids and the EV charging facility and the value of shared power will be dictated by the designed droop control scheme. |