6.78-MHz, 50-W Wireless Power Supply Over a 60-cm Distance Using a GaN-Based Full-Bridge Inverter

Abstract

An inductive wireless power transfer system is proposed as a power supply for an on-line monitoring system for an overhead catenary. Because of the high voltage (25 kVrms) applied to the catenary, galvanic isolation was required to supply power to the attached monitoring system. The proposed wireless power system was able to transmit 50 W over a distance of 60 cm at 6.78 MHz. Design methodologies for the transmitter and the receiver coils, 6.78-MHz GaN-based full-bridge inverter, and rectifier are proposed in this paper. Pareto optimality, a multi-objective optimization technique, was used to determine optimal solutions in terms of efficiency and copper usage. A 100-W, 6.78-MHz full-bridge inverter was developed using 100 V, 35 A, E-HEMT GaN MOSFETs. Because of the high operating frequency, two factors were considered in the design of the full-bridge inverter, (1) close placement of the gate driver and the switch to minimize parasitic inductance and the resulting fluctuation of the drive signal and (2) effective heat dissipation from the switches and gate drivers for a high power rating. In addition, a full-wave rectifier was built using Schottky barrier diodes with a reverse recovery time of a few tens of nano-seconds. The developed wireless power system was experimentally evaluated. The measured coil-to-coil efficiency was 77%, and the measured efficiencies of the inverter and the rectifier were 92% and 93%, respectively. The overall system efficiency was 57% for a transfer of 47 W. Finally, the dependences of the efficiency on the distance, operating frequency, and load were evaluated.

The modelling, simulation, and implementation of wireless power transfer for an electric vehicle charging station

“…On the other hand, Lee examined in his study in 2019 that WPT systems can be adapted in different sizes in places where it is difficult to reach. Also, he transferred 47 W power with 52% efficiency with WPT at a distance of 60 cm which is the approach distance of the high voltage lines (Lee et al, 2019).…”

Minimum Power Input Control for Class-E Amplifier Using Depletion-Mode Gallium Nitride High Electron Mobility Transistor

“…Thus, they have been used in various applications, such as battery charging [2], drones [3], LED lighting [4], and biomedicine [5]. Many studies have demonstrated the excellent performance of class-E power amplifiers [6,7], particularly when gallium nitride high electron mobility transistors (GaN HEMTs) are used [7][8][9][10][11]. GaN HEMTs provide high efficiency and performance due to their exceptional characteristics, such as low gate charge loss [7] and gate-source capacitance, which almost produce an ideal ZVS [8,9].…”