Nduwamungu, AphrodisLie, Tek TjingNair, Nirmal KCLestas, Ionis2026-03-302026-03-302026-05Engineering Science and Technology, an International Journal, ISSN: 2215-0986 (Print), Elsevier BV, 77, 102327-102327. doi: 10.1016/j.jestch.2026.1023272215-0986http://hdl.handle.net/10292/20830This paper investigates advanced nonlinear control strategies for a Quad Active Bridge (QAB) resonant converter supplying pulsed power loads (PPLs) in DC microgrids, where fast load transients and inter-port coupling challenge voltage stability. Three controllers are designed and evaluated for regulating the 48 V ports 3 and 4 under a PPL step from 100 W to 200 W : ASSOSMC, IHOSMC, and CMPC–ISMC. In terms of voltage regulation, ASSOSMC achieves the smallest peak deviations ( Δ V 3 = 0 . 5 V , Δ V 4 = 0 . 3 V ), whereas IHOSMC and CMPC–ISMC exhibit larger voltage dips of 3 . 0 / 2 . 8 V and 3 . 5 / 4 . 2 V at ports 3/4, respectively. Overshoot is kept below 1.531% (ASSOSMC) and limited to 0.667% (IHOSMC and CMPC–ISMC), with fast settling times of 3 . 6 μ s (ASSOSMC and CMPC–ISMC) and 4 . 7 μ s (IHOSMC). Energy efficiency is evaluated from steady-state averaged port powers over a common interval ( t = 2 . 1166 – 2 . 8610 s ): CMPC–ISMC achieves the highest overall efficiency ( η tot ≈ 90 . 775 % ), followed by ASSOSMC ( η tot ≈ 90 . 724 % ) and IHOSMC ( η tot ≈ 89 . 055 % ). Hardware-in-the-loop validation on an OPAL-RT platform confirms the effectiveness of the proposed controllers for stabilizing QAB port voltages under PPL disturbances, and highlights CMPC–ISMC as a balanced solution combining high efficiency with reduced current stress on the regulated ports.© 2026 The Authors. Published by Elsevier B.V. on behalf of Karabuk University. This is an open access article distributed under the terms of the Creative Commons CC-BY license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. You are not required to obtain permission to reuse this article.40 Engineering4008 Electrical Engineering4009 Electronics, Sensors and Digital Hardware7 Affordable and Clean EnergyIntegral HOSMModel predictive control with ISMCASSOSMCOPAL-RTJournal ArticleOpenAccess10.1016/j.jestch.2026.102327