Multi-MHz Auto-Resonant Power Oscillator in a 650 V GaN-on-SOI Technology for Compact Wireless Power Transfer Systems

In this research, we demonstrate a 60 W, 60 V, 3 MHz auto-resonant integrated power oscillator implemented on IMEC’s 650 V GaN-on-SOI MPW process. The monolithic integrated circuit, with dimensions of 2.$5\times$ 2.5mm$^{2}$, incorporates the switching cell of the so-called Royer-Circuit which can be used both in transmitter (inverter) and receiver (rectifier) circuits for WPT systems. Designed for power levels of 100W, the chip can handle maximum input voltages up to 150V and switching frequencies in a single-digit MHz range. The integrated design as well as MHz switching frequencies allow for a very compact and simple WPT system. This paper describes the operation and functionality of the Royer converter including the processed GaN-Royer IC and addresses important aspects of the integration of the circuit. The operation and performance of the designed IC is demonstrated in operation at resonant frequencies of up to 3MHz and output powers up to 100W at an input voltage of maximum 60V. The whole WPT system, including a Royer converter as transmitter and receiver reaches efficiencies between DC in and DC out up to $\eta = 90\%$. The limitations and further optimizations for such a converter system are discussed at the end of the paper.