Power management strategy research for DC microgrid with hybrid storage system

Abstract

Due to the defects of the way of the traditional grid power supply, microgrid arises at the historic moment. At present, DC microgrid is an effective solution to integrate renewable energy sources which are DC power supply with DC loads. In allusion to the power unbalance intra-microgrid and the wide fluctuation of DC bus voltage due to unstable output of DC micro resources in DC microgrid, A DC microgrid structure consisting of photovoltaic generation system, hybrid energy storage systems and AC main grid, is researched in this paper. A novel power management strategy for this DC microgrid is proposed. The control strategy divides the DC bus voltage into seven ranges by six critical voltage values which are employed as the represents of power states, and according to the range which the bus voltage belongs to, the operation mode of the system can be automatically judged and switched freely. A hybrid energy storage system in this microgrid that contains two complementary type storage elements---battery and super-capacitor, can enhance the reliability and flexibility of the system based on their special supply logical. Experimental results show that above-mentioned control strategy is feasible through the MATLAB/SIMULINK simulation platform.

A Review on the Selected Applications of Battery-Supercapacitor Hybrid Energy Storage Systems for Microgrids

“…The HESS is integrated into the shunt and series inverters, with BESS delivering average load power during voltage interruption and SCSS providing load peak power fluctuation. The study in [142] investigates DC microgrid with HESS and posits a novel power management strategy for the integration of unstable RES DC grid to traditional grid power supply network. The DC bus voltage is employed as a carrier to represent operation modes of the system based on critical DC voltage conditions, the control strategy automatically judges and switches within the specified seven ranges of power operation state formed by six critical DC bus voltages.…”

Energy Balance Control of Energy Storage System Based on Improved Virtual DC Motor

“…For the discontinuity and instability of renewable energy sources, energy storage technology can effectively splice these discontinuous renewable energy sources together and transform them into a continuous and stable energy supply [2]. Energy storage systems can absorb grid energy and release energy at the same time, playing the role of peak and valley filling [3]. Compared to generators that dominate conventional power systems, most of the energy storage system access is based on the power electronic converter interface, which itself does not have rotational inertia conducive to maintaining system voltage stability.…”

Power Hardware In the Loop and Ancillary Service for Voltage Regulation in Low Voltage Grid

“…In terms of grid connection capabilities, the microgrid is linked to the main grid via the PCC; the integration of renewable energy sources or smaller generators gives an opportunities to participate in the energy market [12]. It should ideally include features to enable standalone modes of operation when an issue such as fault is experienced in the grid network depending on the design and type of power sources available; an effective system could also be included for the management and coordination of critical and non-critical loads during an emergency that would temporarily allocate loads based on the available generators [13][14][15].…”