A wireless power transfer system is a device which uses electromagnetic induction to provide electric power without physical contact. They can be used for various applications, such as moving or rotating devices, or devices sealed inside enclosed spaces. Because the primary and secondary sides do not touch, the power transmission efficiency and leakage flux vary depending on their positions relative to each other. Therefore, it is important at the design stage to understand how properties change according to their placement.
When evaluating the properties of a transformer whose primary and secondary sides are separated by a gap, it is helpful to use magnetic field analysis based on the finite element method (FEM), which allows precise modeling of the geometry of the parts and their relative positions, and makes it possible to visualize the leakage in the magnetic flux that is generated in the primary side and transmitted to the secondary side.
This Application Note presents how to obtain the power transmission efficiency when the feeder wire’s position is moved in both the horizontal and vertical directions from a reference position, and how to display the flow of magnetic flux.