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Fe-based soft magnetic material such as amorphous or nanocrystalline alloy is an alternative to the ferrite for magnetic cores of the medium-frequency transformers (MFTs) due to its high permeability and magnetic saturation. However, accurate core loss modeling is one of the major obstacles to design a high-power-density MFT, especially when considering the nonlinearity hysteresis B-H loop. Besides, the magnetostriction that exhibits hysteresis characteristic causes the vibration issue. Several studies have proven that the high intensity of acoustic noise will do harm to the human's mental and physical health. However, the research on the modeling of the acoustic vibration caused by magnetostriction has been scarcely conducted. In this article, the Jiles–Atherton (J-A) model is applied to describe the hysteresis characteristic of the B-H and H-strain for the Fe-based soft magnetic material. The J-A magnetic and magentomechanical hysteresis models were incorporated into the finite element analysis (FEA) under the multiphysics simulation environment in order to estimate the core loss and temperature rise of the MFT. The acoustic vibration FEA model of the MFT was built based on the H-strain hysteresis J-A model. The fidelity of the simulated acoustic noise pressure was verified by the experiment test results. The proposed models in this article can be effective tools to evaluate the hysteresis magnetic and magnetomechanical behavior of the core in the MFT.

Fe-based nanocrystalline ribbon is an alternative to the ferrite for high-frequency magnetic cores due to its low hysteresis loss and high magnetic saturation. The drawback of the Fe-based nanocrystalline ribbon is its high conductivity. Crushing the homogenous ribbon to restructure a nanocrystalline flake ribbon (NFR) can reduce the conductivity while maintaining other superior magnetic properties of the noncrushed nanocrystalline ribbon. So far, several previous works have proven that the NFR can replace the ferrite in the dual active bridge and wireless power transfer system. However, seldom of these works mention the detailed mechanism of the NFR. In this article, the structure and manufacturing process of the NFR are introduced. The effect of the relative permeability and the crushing pattern on the magnetic properties of NFR has been quantitatively reported. A dual-permeability core formed by two types of NFR has been demonstrated for an inductor. Comparison has been made to inductors using the ferrite core (N27, N87, DMR44) in a similar size. Experiment results show that the dual-permeability NFR core has a lower core loss and higher magnetic saturation than the ferrite counterparts at frequencies from 100 to 300 kHz.

Wireless/contactless charging of electric vehicles can improve the safety and convenience of the electric vehicle charging process. However, in order to enable wireless charging on an electric vehicle, additional components need to be added to the vehicle, which increase the cost, and weight of the vehicle. Specifically, a wireless receiver coil and power electronics are required to receive the wireless power and charge the battery. This work proposes a new integrated wireless charger, which reuses the existing drivetrain components, such as the traction inverters and the motor, to serve as the receiver-side power electronics for wireless charging. Importantly, this topology limits the high frequency currents entering the traction components, such as the motor, which are susceptible to high frequency losses. The drivetrain can serve to control the charging rate of the batteries, which eliminates the need for transmitter side battery charging control and communication. Experimental validation was done by coupling a 110 kW EV machine and dual-inverter drivetrain to a 6.6 kW wireless transmission system. A peak charging efficiency of 94.3% over a vertical coil distance of 200 mm was achieved.