Novel model reference-based hybrid decoupling control of multiport-isolated DC-DC converter for hydrogen energy storage system integration
Oyedotun E. Oyewole, Ali A. Abdel-Aziz, Ibrahim Abdelsalam, Eugene Bari, Khaled H. Ahmed
Abstract
Hydrogen energy storage systems (HESS) are increasingly recognised for their role in sustainable energy applications, though their performance depends on efficient power electronic converter (PEC) interfaces. In this paper, a multiport-isolated DC-DC converter, characterised by enhanced power density, reduced component count, and minimal conversion stages, is implemented for HESS applications. However, the high-frequency multiwinding transformer in this converter introduces cross-coupling effects, complicating control and resulting in large power deviations from nominal values due to step changes on other ports, which adversely impact system performance. To address this issue, a novel model reference-based decoupling control technique is proposed to minimise the error between the actual plant output and an ideal decoupling reference model, which represents the cross-coupling term. This model reference-based decoupling control is further extended into a hybrid decoupling control technique by integrating a decoupling matrix, achieving more robust decoupling across a wider operating region. The hybrid decoupling technique mathematically ensures an improved control performance, with the cross-coupling term minimised through a proportional-derivative controller. The proposed hybrid decoupling controller achieves a maximum power deviation of <3 % under various conditions, outperforming the conventional inverse decoupling matrix technique, which typically exhibits higher deviations under similar conditions. The effectiveness of the hybrid decoupling control is validated through simulations and experimental results, demonstrating significant improvements in decoupling performance. • Proposes a multiport-isolated DC-DC converter for HESS, achieving reduced conversion stages and improved power density. • Presents a hybrid decoupling control of the converter, eliminating lookup table and enhancing decoupling over wider region. • Provides a detailed mathematical model to analyse cross-coupling effects and derive an ideal decoupled model. • Demonstrates significant performance gains of the proposed technique compared to conventional decoupling controls. • Validates the proposed decoupling technique through comprehensive MATLAB/SIMULINK simulations and 380 W hardware prototype.