Wireless Power Transfer

2018

I worked on a reserch project involving wireless power transfer while a grad student at Michigan. The point of the research was control, not power electronics, but the group was having difficulty testing their control circuitry without reliable power electronics. They had been using EPC GaN evaluation boards as half bridge drivers, and they were blowing up left and right. To allow the research to continue at higher power levels, I built several driver boards using both silicon and GaN FETs.

Both Coils, One Capacitor Board, and the Rectifier

Half Bridge Driver

I built a half bridge driver board, a rectifier board, the transmit and receive coils, and a resonant capacitor board my first semester. This driver board worked well - The system could handle 500W continuously over a 10cm gap at 92% efficieny - but it was still possible to accidentally destroy it by driving the circuit at resonance unloaded. The second semester, I built a full bridge driver board with phase overcurrent protection, input overcurrent protection, and a latching failsafe mode.

Coil on Stand

Back of Coil on Stand with Resonant Capacitor Board

Heat Sink on Bottom of the Board

Second Revision Full Bridge Driver Board

Bottom of Full Bridge Driver

GaN Version of Full Bridge Driver

Bottom of GaN Version