Design of a Hybrid Energy Storage System for Improved Voltage and Frequency Control in a Multi Energy Resource Isolated Microgrid Power System Using an Enhanced Dynamic Droop Control Method

Abstract

This study was conducted basically to improve the voltage and frequency control system of hybrid energy storage system (HESS) microgrid using iteration method of dynamic droop gain control strategy. Six (6) Hybrid Energy Storage System (HESS) arrangement were considered and they were formed by different combinations of Battery Energy Storage System (BESS), Superconducting Magnetic-based Energy Storage (SMES) and also Supercapacitor (SUPCA) system as the new introduction into the HESS microgrid. The use of existing constant and dynamic droop-controlled technique on these arrangements were then compared with the new and enhanced constant and dynamic droop-controlled technique using MATLAB and iteration method. The results showed that the introduction of SUPCA in the HESS help to achieve; one, good frequency control and voltage-stabilization, two, improved and extended service time and lifespan of battery due to improvement in state-of-charge (SOC). The results also revealed that the improved HESSs showed better frequency and voltage regulation capabilities. Thus, it was concluded that the proposed enhanced dynamic droop-control technique significantly exploits the different features of SUPCA, SMES and BESS to form a sort of complementing HESS. Hence, it was recommended that the BESS in the new control system would significantly protect it from short-term frequency change cycles, Voltage changes and sudden change in currents, lifespan.