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This article proposes a novel approach for operating hybrid fuel cell and battery power systems in marine vessels. The target of the approach is to reduce energy losses in drivetrain devices. In the proposed approach, the dc bus voltage of the hybrid power system is adjusted according to fuel cell operating points, which enables operation in freewheel mode, and thus significantly reducing power conversion losses. Feasibility of the proposed approach is verified using a real-time hardware-in-loop simulation setup consisting of prevalidated virtual models and real industrial power converter controllers. The results presented in the work illustrate that the variable dc approach enables significant improvements in drivetrain efficiencies, and thus providing significant savings for vessel operators. Additionally, variable dc approach is shown to eliminate high-frequency current ripple at the fuel cell terminals, which can further improve the efficiency and the lifetime of the fuel cells. [ABSTRACT FROM AUTHOR]

The use of multiple transmitters (Txs) has been an attractive solution for enabling free-positioning wireless power transfer (WPT) in a large area. One of the key challenges in such multi-Tx WPT systems is the cross-coupling between Tx coils. This letter proposes a compact self-decoupled Tx coil solution for multi-Tx WPT systems. The measured cross-coupling between Tx coils has been reduced by 95% compared with conventional coil designs. In addition, an integration method for a compensation inductor with the main Tx coil is proposed. Therefore, the coil design proposed in this letter facilitates creation of fully modular and scalable Tx coils for multi-Tx WPT systems. The proposed designs are experimentally verified in a laboratory prototype. [ABSTRACT FROM AUTHOR]

A new implementation of an iron-loss model for laminated magnetic cores in the MATLAB/Simulink environment is proposed in this paper. The model is based on numerically solving a one-dimensional diffusion problem for the eddy currents in the core lamination and applying an accurate hysteresis model as the constitutive law. An excess loss model is also considered. The model is identified merely based on the catalog data provided by the core material manufacturer. The implementation is validated with analytical and finite-element models and experimentally in the case of a toroidal inductor supplied from a GaN FET full-bridge inverter with 5–500 kHz switching frequencies and a deadtime of 300 ns. Despite the simple identification, a good correspondence is observed between the simulated and measured iron losses, the average difference being 3.3% over the wide switching frequency range. It is shown that accounting for the skin effect in the laminations is significant, in order to correctly model the iron losses at different switching frequencies. Some differences between the measured and simulated results at high switching frequencies are also discussed. The model is concluded to be applicable for designing and analyzing laminated magnetic cores in combination with power-electronics circuits. The Simulink models are openly available. [ABSTRACT FROM AUTHOR]