Skip to content

Announcement of a Defense of a Thesis- Hoang Phuc T. (Peter) Pham

Hoang Phuc T. (Peter) Pham,
Candidate for Master of Science
Defense of a Master's Thesis
Faculty Advisors: Leon Tolbert, Daniel Costinett

Design of Power Receiving Units for 6.78 MHz Wireless Power Transfer Systems


In the last decade, the wireless power transfer (WPT) technology has been a popular topic in power electronics research and increasingly adopted by consumers. The Airfuel WPT standard utilizes resonant coils to transfer energy at 6.78 MHz, introducing many benefits such as longer charging distance, multi-device charging, and high tolerance of the coil misalignment. However, variations in coil coupling due to the change in receiving coil positions alter the equivalent load reactance, degrading efficiency. 

In recent studies, active full-bridge rectifiers are employed on WPT receivers because of their superior efficiency, controllability, and ability to compensate for detuned WPT networks. In order to take advantage of those characteristics, the rectifier switching actions must be synchronized with the magnetic field. In the literature, existing solutions for synchronizing the active rectifier in WPT systems are mostly not reliable and bulky, which is not suitable for small receivers. Therefore, a frequency synchronous rectifier with compact on-board control is proposed in this thesis. The rectifier power stage is designed to deliver 40 W to the load while achieving full zero-voltage switching to minimize the loss. The inherent feedback in the synchronization loop is analyzed to design stable and robust synchronization control, even at a low power of 0.02 W. The control system is accomplished using commercial components, including a low-cost microcontroller, which eliminates the need for bulky control and external sensing hardware. This high power density design allows the receiver to be integrated into daily consumer electronics such as laptops and monitors. Finally, a wide-range and high-resolution control scheme of the rectifier input phase is proposed to enable the dynamic impedance matching capability, maintaining high system efficiency over wide loading conditions. 

In addition, to increase the WPT technology adoption to low-power consumer electronics, a small wireless receiver replacing conventional AA batteries is developed. This receiver can supply power to existing AA battery-powered devices while providing the benefit of WPT technologies to consumers.

Dial-In Information

Zoom information

Time: Aug 5, 2020 09:30 AM Eastern Time (US and Canada) 

Email Hoang Phuc T. (Peter) Pham ( to request Zoom password.

Join from PC, Mac, Linux, iOS or Android:

Or iPhone one-tap (US Toll):  +13017158592,5261942061#  or +13126266799,5261942061# 

Or Telephone:
    +1 301 715 8592 (US Toll)
    +1 312 626 6799 (US Toll)
    +1 646 876 9923 (US Toll)
    +1 253 215 8782 (US Toll)
    +1 346 248 7799 (US Toll)
    +1 669 900 6833 (US Toll)
    Meeting ID: 526 194 2061
    International numbers available:

Or an H.323/SIP room system:
    H.323: (US West) or (US East) 
    Meeting ID: 526 194 2061
    Password: 08052020


Wednesday, August 5, 2020 at 9:30am

Virtual Event
Event Type

Lectures & Presentations




Current Students, Faculty & Staff


Defense, electrical engineering, master's, thesis

Electrical Engineering and Computer Science
Google Calendar iCal Outlook

Recent Activity