An Energy Management System-Based Control Strategy for DC Microgrids with Dual Energy Storage Systems

Abstract

In this work, a control strategy is developed for different components in DC microgrids where set points for all controllers are determined from an energy management system (EMS). The proposed EMS-based control scheme is developed for DC microgrids with solar photovoltaic (PV) systems as the primary generation units along with energy storage systems. In this work, the concept of dual energy storage systems (DESSs) is used, which includes a battery energy storage system (BESS) and supercapacitor (SC). The main feature of this DESS is to improve the dynamic performance of DC microgrids during severe transients appearing from changes in load demands as well as in the output power from solar PV units. Furthermore, the proposed EMS-based control scheme aims to enhance the lifetime of the BESS in DC microgrids with DESSs and voltage stability as compared to the same without SCs. The proposed EMS-based control strategy uses proportional-integral (PI) controllers to regulate the switching control actions for different converters within the DC microgrid based on the decision obtained from the EMS in order to achieve the desired control objectives. The performance of the proposed scheme was analyzed through simulation results in terms of improving the voltage stability, maintaining the power balance, and enhancing the lifetime of BESSs within a DC microgrid framework incorporated with the DESS. The simulations are carried out in the MATLAB/SIMULINK simulation platform and compared with a similar approach having only a single energy storage system, i.e., the BESS.

Design of Robust Integral Terminal Sliding Mode Controllers with Exponential Reaching Laws for Solar PV and BESS-Based DC Microgrids with Uncertainties

“…The analogous circuit layout of a solar PV unit with a DDBC is shown in Figure 2. From Figure 2, using Kirchhoff's voltage and current laws, the mathematical model can be introduced as follows [9]:…”

“…An MG system can be classified into two categories based on the type of common DC-bus voltage: DCMG and ACMG [7]. However, the DCMG is gaining more prominence over the ACMG owing to several benefits, such as the fact that it is not essential to synchronize it with the existing grid and it has no frequency and reactive power control [8,9].…”

“…When there is insufficient power from the solar PV to satisfy load demands, an ESS will supply the shortage power to the DC-bus to maintain the power balance. Furthermore, when there is extra power after meeting the load demands, the excess power will be stored in the ESS [9,13]. However, to achieve this goal, an ESS must be connected to a BDDC to operate it in boost or buck modes depending on its state of charge and the DC-bus voltage state [14].…”

A nonlinear double‐integral sliding mode controller design for hybrid energy storage systems and solar photovoltaic units to enhance the power management in DC microgrids

“…The decentralized controller for DCMGs can be considered as an alternative option as it increases the scalability and reliability without requiring any communication links among local controllers [24][25][26][27][28][29]. A decentralized droop control scheme is presented in [24][25][26] where the control action is obtained by emulating the virtual impedance at the output of the power converter.…”

Design of Nonlinear Backstepping Double-Integral Sliding Mode Controllers to Stabilize the DC-Bus Voltage for DC–DC Converters Feeding CPLs

“…Recently, the power electronicbased DC distribution networks (DCDNs) are becoming more popular owing to their distinct advantages in terms of efficiency, controllability, flexibility, etc. [6,7]. However, two major challenges need to be addressed for a stable and reliable operation of power electronic-based DCDNs in conjunction of RESs, where the first challenge is the low terminal voltage of RESs while important to maintain a relatively high and stable terminal voltage of the DC-bus as all loads and RESs are either directly or indirectly connected to this bus [8][9][10].…”