Page 37 - KVIS Book

PHY02I

Study, Design, and Construction of Transmitter for Efficient
Wireless Power Transfer

Kornrapat Pongmala, Ployprakai Pusee, Pitchayut Bumrungsiri
Kamnoetvidya Science Academy, Thailand
Supervisor: Min Medhisuwakul
Email: kornrapat_p@kvis.ac.th

Wireless charging technology is becoming more crucial in our daily lives as there are
more commercial products in the market. However, magnetic induction method in the
wireless charger only has the capacity to charge in a short range. This research aimed
to identify the characteristics of the inductor of Qi wireless charger in which to be
altered to increase the range of a typical Qi wireless charger and still can be used to Qi
standard phones. Two main factors that allow successful wireless charging is the
resonant frequency and the electromotive force induced in the receiving coil. Various
models of inductor are constructed and tested for the value of resonant frequency and
electromotive force induced at different range. Some basic Physics principles were
applied and the data from each model were compared and used to identify the
preferred properties of the transmitting inductor. Then, an inductor is constructed
based on those properties and tested. The result identified 3 factors as having effects
on charging range: resistance of the inductor, mutual inductance, and self-inductance.

Keywords: Wireless charging, Qi wireless charger, Charging range, Resonant frequency,
Self-inductance, Mutual inductance