ABSTRACT This paper presents a coordinated energy management system (EMS) for a fuel cell (FC) and supercapacitor (SC) hybrid system interfaced through three isolated dual active bridge (DAB) converters. In this architecture, the first DAB supplies the steady‐state DC bus load, second DAB provides transient and overload support and the third DAB enables direct FC to SC charging. The EMS uses measured DC bus voltage, load current and SC state of energy to coordinate converter activation. MATLAB/Simulink results for an 8 s case study show DC bus recovery to within in less than 5 ms, with a maximum voltage undershoot of 2.5 V during a load step from 13.3 to 16 A. Small‐signal analysis of the DC bus voltage control loop confirms robust closed‐loop stability with a phase margin of about and a crossover frequency of 2.27 kHz (). The dedicated charging path removes one intermediate conversion stage compared to a conventional charging path where the SC is charged via the DC bus. This reduces the number of conversion stages and associated losses and improves the effective charging‐path efficiency.
Ijaz et al. (2026) studied this question.