As the presence of wireless power transfer technology increases in consumer electronics, the industrial and medical industries are shifting focus towards this technology and its inherent advantages. As communication interfaces are becoming increasingly wireless With technologies like WLAN and Bluetooth, wireless power transfer has become a relevant option. Completely new approaches can be taken that not only offer obvious technical advantages, but also open up possibilities for new industrial design. This technology offers new concepts - especially in industrial sectors struggling with tough environmental conditions, aggressive cleaning agents, heavy soiling and high mechanical stresses (e.g. ATEX, medicine, construction machines). For instance, expensive and susceptible slip rings or contacts can be substituted. Another field of application is with transformers, which have to satisfy special requirements, such as reinforced or doubled insulation. The target of this Application Note is to demonstrate that easy-to-achieve solutions for wireless power transfer of one hundred Watts or more are reachable using circuit technology, without the need of software or controllers.

Summary

This resonant converter is very flexible and can be adapted to the requirements of many different applications This circuit currently represents the most effective wireless transfer of energy of up to several hundred Watts. If the demands of the application grows in terms of safety, On/Off, charging state detection etc., this circuit can serve as the basis and be extended by the hardware developer. A classical H bridge circuit with active regulation can also be taken as the basis rather than the resonant converter topology. In any case, EMC measurements should be performed on the first prototypes at an early stage during development.

High efficiency, the most compact package and good EMC properties essentially depend on the clocking circuit, as well as the transmitter and receiver coils. Besides the widest product range, Würth Elektronik also offers coils with the highest Q factors in their respective packages. This allows higher inductance values to be attained and results in smaller packages for the capacitors. In addition, HF litz (stranded) wire is used exclusively for high power (lower AC losses) with high quality ferrite material (high permeability). This means the maximum efficiency and best possible EMC performance for the end product.

Download: ANP032