Adaptive Energy Management Strategy for Optimal Power Flow Control of Hybrid DC Microgrid

In this work, an adaptive energy management strategy (AEMS) is proposed to achieve the optimal power flow control of off grid connected hybrid DC Microgrid (MG) against time varying source and load dynamics. The hybrid DC MG considered in this paper is operating with a solar PV array and mini hydro power plant (MHPP) as power dispatching sources. The intermittent input dynamics of solar PV system and time varying load power dynamics results in power fluctuations of hybrid DC MG. The MHPP cannot regulate these power fluctuations instantly due its operating dynamics. Therefore, AEMS has deployed a hybrid energy storage system (HESS) comprising battery and supercapacitor storage devices for compensating such power dynamics. The intermittent dynamics of solar PV array may force the battery storage of HESS into deep charging/discharging mode which again results in power fluctuations of hybrid MG. To avoid deep charging/discharging of battery storage system, AEMS has employed an adjustable gate positioning system which adjusts the gate opening/ closing position of servo mechanism for regulating the power output of MHPP. Moreover, adjustable gate positioning system doesn't going to effect the steady state output power of MHPP. This is the unique feature of AEMS. Adaptive power manger set the reference power to be delivered by MHPP in such a way that it compensates the time varying load power variations against its operating dynamics. In this paper, voltage control at the DC bus of hybrid MG is used to evaluate the power flow control with the proposed AEMS. The proposed methodology is validated using MATLAB SIMULINK software.