Control of high-energy high-power densities storage devices by Li-ion battery and supercapacitor for fuel cell/photovoltaic hybrid power plant for autonomous system applications

This study presents an energy management approach for a hybrid energy system comprised of a photovoltaic (PV) array and a polymer electrolyte membrane fuel cell (PEMFC). Two storage devices (a Li-ion battery module and a supercapacitor (SC) bank) are used in the proposed structure as a high-energy high-power density storage device. Multi-segment converters for the PV, FC, battery, and SC are proposed for grid independent applications. Nonlinear differential flatness-based fuzzy logic control for dc bus voltage stabilization for power plant are investigated. To validate the control approach, a hardware system is realized with analog circuits for the PV, FC, battery, and SC current control loops (inner controller loops) and with numerical calculation (dSPACE) for the external energy control loop. Experimental results with small-scale devices [a photovoltaic array (800 W, 31 A), a PEMFC (1200 W, 46 A), a Li-ion battery module (11.6 Ah, 24 V), and a SC bank (100 F, 32 V)] demonstrate the excellent energy-management scheme during load cycles.