Wireless charging

Wireless charging is currently becoming a hot topic for marketing, consequently, for a design as well. However, wireless energy transfer principle is not new and already well-known. Specifically, this principle is used in electromechanical apparatus such as transformers. The only difference is that in a transformer transferring and receiving coils are motionlessly mounted on a static part, magnetic yoke, which guides the magnetic field from one coil to another. Therefore, it is possible to say that the energy is transferred via the specific magnetic path. However, there is a special class of electromechanical devices that indeed implement wireless energy transfer - electrical machines. They transfer the energy from static to rotating part or vice versa through a real, physical air gap. As so, we can conclude that wireless energy transfer…
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Transformer: 2D vs 3D modeling

When modeling an electromechanical device, a designer needs to keep in mind that a 2D problem set introduces an error in a field distribution in comparison with a 3D problem solution. However, a solving process of 2D problems is multiple times faster than of 3D. So, what is a range of the error specifically for a transformer design application? An example of transformer is shown on the pictures. It has a rectangular iron core with 15 turns of primary coil (all dimensions are in millimeters). [caption id="attachment_13" align="alignnone" width="150"] 3D view[/caption] [caption id="attachment_15" align="alignnone" width="285"] Front view[/caption] [caption id="attachment_16" align="alignnone" width="80"] Side view[/caption] A 2D model considers only a part of a coil with a current direction “in” and “out” a plane and neglecting end effects of “front” and “end”…
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