Author(s)

JueXiao Chen¹, EnYong Li¹, Lei Shi^1*, ZhongYao Jiang^2*      

Affiliation(s)

¹School of Automotive and Energy Studies, Tongji University, Shanghai 201804, China.

²Jiangsu Qunling Energy Technology Co., Ltd, Nantong 226407, Jiangsu, China.

Corresponding Author

Lei Shi, ZhongYao Jiang 

ABSTRACT

Fuel-cell power conditioning systems require DC–DC converters to achieve high efficiency, wide-range voltage regulation, and reliable operation under significant input and load variations. To address these requirements, this paper investigates an IPOS-type secondary LLC resonant DC–DC converter and proposes a hybrid control strategy combining pulse-frequency modulation (PFM) and phase-shift modulation (PSM). In the proposed scheme, PFM is employed as the primary control method to realize wide-range voltage regulation, while a frequency-clamping with phase-shift compensation mechanism is introduced to maintain effective power control and dynamic performance when the switching frequency reaches its practical upper limit. The effectiveness of the proposed topology and control strategy is validated through MATLAB/Simulink simulations and experimental studies on a laboratory prototype. Experimental results demonstrate a peak conversion efficiency of 96.6% under rated conditions, with efficiency remaining above 96% near the rated load range. In addition, the maximum output voltage deviation between two IPOS phases is limited to 1.9% under full-load operation, and fast, stable input-current tracking is achieved under step reference changes from 20 A to 80 A without noticeable overshoot. These results confirm that the proposed converter and hybrid control strategy are well suited for high-efficiency, wide-range fuel-cell energy conversion applications.

KEYWORDS

Fuel cell system; LLC resonant converter; Hybrid control

CITE THIS PAPER

JueXiao Chen, EnYong Li, Lei Shi, ZhongYao Jiang. Hybrid-controlled IPOS LLC converter for fuel cell applications. World Journal of Engineering Research. 2026, 4(1): 49-59. DOI: https://doi.org/10.61784/wjer3079.

REFERENCES

[1] Basha C H H, Mariprasath T, Murali M, et al. Simulative design and performance analysis of hybrid optimization technique for PEM fuel cell stack based EV application. Materials Today: Proceedings, 2022, 52: 290-295.

[2] Gunasekaran A, Sambasivam R, Ashokan A, et al. Realistic Simulation Analysis and Performance Testing Of One KW Fuel Cell Powered Three-Wheeler. Results in Engineering, 2025: 106336.

[3] Ramya V, Marimuthu R. A review on multi-input converters and their sources for fast charging of electric vehicles. Engineering Science and Technology, an International Journal, 2024, 57: 101802.

[4] Bairabathina S, Balamurugan S. Review on non-isolated multi-input step-up converters for grid-independent hybrid electric vehicles. International journal of hydrogen energy, 2020, 45(41): 21687-21713.

[5] Nie J, Meng L, Zhang H, et al. A three-level three-power-channel hybrid converter with wide voltage range for renewable energy medium voltage DC systems. Energy, 2025: 136940.

[6] Keerthi A, Dhanamjayulu C. A Thorough Review of Energy Management and an Advanced Control Techniques for Bi-directional DC-DC Converters in Electric Vehicle Applications. Results in Engineering, 2025: 106726.

[7] Abolghasemi M, Soltani I, Shivaie M, et al. Recent advances of step-up multi-stage DC-DC converters: A review on classifications, structures and grid applications. Energy Reports, 2025, 13: 3050-3081.

[8] El Hmidi J, Mansouri A, Ahaitouf A. Optimization approach of LLC resonant converter parameters for electric vehicles based on interior-point algorithm. Scientific African, 2025: e02939.

[9] Mahazabeen M, Abianeh A J, Ebrahimi S, et al. Enhancing ev charger resilience with reinforcement learning aided control. e-Prime-Advances in Electrical Engineering, Electronics and Energy, 2023, 5: 100276.

[10] Celik O, Teke A, Tan A. Overview of micro-inverters as a challenging technology in photovoltaic applications. Renewable and Sustainable Energy Reviews, 2018, 82: 3191-3206.

[11] Wang D, Li N, Liu M, et al. Study on phase-shift value optimization strategy for extending soft-switching range of buck-boost LLC converters. Electric Power Systems Research, 2026, 251: 112250.