Electric Vehicle Battery Charger: Wireless Power Transfer System Controlled by Magnetic Core Reactor

This paper presents a control process and frequency adjustment based on the magnetic core reactor for electric vehicle battery charger. Since few decades ago, there have been significant developments in technologies used in wireless power transfer systems, namely in battery charger. In the wireless power transfer systems is essential that the frequency of the primary circuit be equal to the frequency of the secondary circuit so there is the maximum energy transfer. The magnetic core reactor allows controlling the frequencies on both sides of the transmission and reception circuits. Also, the assembly diagrams and test results are presented.

Improving magnetic coupling for battery charging through 3D magnetic flux

The spatial distribution of the magnetic field and the coupling between the coils in the Wireless Power Transfer (WPT) systems is an important aspect to consider in the system design and efficiency optimization. The presented study in this paper is based on tests performed on a physical model. The transmitting (primary) equipment, is an electrical three-phase system, capable to be connected in star or delta (both electrically and geometrically). The measured results allow to describe graphically the magnetic field distribution in three dimensions. The analytical formulas aim to help to understand and to quantify the physical phenomena but they cannot be considered a universal approach and the measurement results help to understand better the observable facts. In the WPT, the key issues that will influence the efficiency, are the alignment of the coils, the spatial orientation of the magnetic field, the detachment and the tilt between the windings, all they changing the magnetic coupling between the transmitter and the receiver of energy. This research is directed not only to the magnetic field distribution but finally, to optimize the energy transfer efficiency.