Abstract
In this article, a highly efficient power module is presented with two class-E power amplifiers and an adaptive power combiner for transmitting output powers >100 W at 6.78 MHz in a wireless power transfer system. The losses caused by the combiners and interstage matching circuits or mismatching between the amplifier, and the combiners can significantly reduce the overall efficiency of the power module. To achieve an efficient combination of the output amplifier signals, the adaptive power combiner is proposed based on the consideration of the optimum load impedance characteristics of the power amplifiers. The input impedance of the combiner is designed using series capacitors and resistors between the two input ports of the combiner and the two output signals of the class-E amplifiers at the optimum load condition. The output performances of the proposed module can decrease based on the component mismatch between the two power amplifiers. The proposed power module was implemented on an FR4 PCB, with a 15 mm metal heat sink, and demonstrated an output power of 123.3 W, a power-added efficiency of 85.7%, and a power gain of 25.6 dB at 6.78 MHz. The second harmonic suppression of the module was 37 dBc.
Highlights
After the demonstration of the wireless power transfer technology, originally proposed by N
A 6.78 MHz signal, with a power of 25.3 dBm from the signal generator, is transmitted transmitted to each input of the class-E power amplifier (PA) by the power divider, which is manufactured by Minito each input of the class-E PA by the power divider, which is manufactured by Mini-Circuits
The proposed power module consisted of two class-E PAs symmetrically designed at the optimum load condition and of an adaptive power combiner that stably obtained an increased combining efficiency
Summary
After the demonstration of the wireless power transfer technology, originally proposed by N. As a wireless power transmission at a distance of 2 m at the Massachusetts Institute of Technology (MIT), this system has been applied to a variety of consumer applications [1,2,3]. Conventional application systems have been used for wireless charging of tablets and cell phones that require a power of, at most, 15 W [4,5]. An output transmitted power of over 100 W is required to obtain a delivered power of over 60 W, when the coupling and the power conversion efficiencies are assumed to be 70% and 90%, respectively. It is necessary to transmit enough power (more than 100 W) at the transmitter with operation stability because the coupling efficiency decreases as the distance between the transmitter and the receiver increases
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
