GaN power element technology has found its way into a major application in the industry with the release of the Dell Latitude computer using the AirFuel standard. Airfuel uses magnetic inductive technology (AirFuel standard) also known as Highly Resonant Wireless Power Transfer by Witricity’s Dr. Morris Kesler.
WiTricity's magnetic resonance technology is seamlessly integrated into the Latitude 7285 Detachable which now can be charged wirelessly over distance and with positional flexibility on a flat surface, which preserves this 2-in-1 notebook's sleek design. WiTricity is different from other forms of wireless charging in that it uses magnetic resonance technology, and this can both charge devices at a distance and through materials (Like a sheetrock wall or a table top), and also doesn't require the device to be precisely aligned to the charging mat.
This is also a significant milestone for WiTricity, which is 10 years old, because it is the first commercially available consumer electronics product to use WiTricity’s technology.
Dr. Alex Lidow, CEO and Co-founder of Efficient Power Conversion (EPC) was able to give me some insights for the Dell/WiTricity project and the contribution that GaN technology is making to this wireless power standard. Lidow commented that magnetic resonance is perfect for flat surfaces, on either horizontal (a mat or embedded into a desk or table top) or vertical (within a wall with a flat-screen TV). Lidow also said that Kitchen countertops can be very dangerous areas having wires running across those surfaces; wireless power adds to safety as well as convenience in this type of application.
The Dell PC has about a one square foot charging area. Lidow said that conventional antenna design prevents us from using magnetic resonance to cover large, room-size areas due to the multiple metal objects that cause interference with the resonance. Recent advances in antenna design, however, have overcome this problem as was demonstrated by EPC last March at the APEC conference. Now we can safely charge multiple products on a large surface such as a desk top or conference room table. As for me, if I could drop my smart watch on my night table to charge it, I would use it again.
WiTricity’s CEO, Alex Gruzen, has commented that it was a ‘significant proof point’ that large global brands (like Dell) can integrate wireless charging into their products. He feels that this will be the ‘new normal’. This and it is a significant starting point. Gruzen feels that magnetic resonance offers a ‘better user experience’ than other competing technologies and that it will ultimately be the technology of choice in the consumer electronics arena.
Dell’s Sr, VP of commercial client solutions, Kirk Schell, said that Dell’s vision is a ‘no-wires workspace’; it will enable the ‘freedom and flexibility today's employees demand’.
Lidow’s Enhancement-mode Gallium Nitride (eGaN) FETs and ICs are ideal for wireless power applications because they can operate at high frequency, high voltage, and high power.
EPC has a wide variety of Wireless Power Demo kits for designers that cover the full power range for Airfuel classes 2, 3, 4 and Multi-Mode for Airfuel and Qi/PMA compatibility for Wireless Power sources. (Image courtesy of EPC)
AirFuel Alliance compatible wireless power kits by EPC (Image courtesy of EPC)
AirFuel Alliance stated that the recent advances in the field of antennas and semiconductors would increase the efficiency of wireless charging at higher frequencies. ICs based on Gallium Nitride (GaN) are the most promising.
For power transmission over air at a frequency of 6.78 MHz, the transmitter must convert DC to AC by turning on / off 6,780,000 times per second. Whenever semiconductor turns on, it requires a small power amplification. This is not possible with Silicon; therefore, the choice is a Gallium Nitride process which is capable of that speed and as a bonus consumes less power.
New Multi-layer antennas soften the phenomenon known as the "skin effect", which adversely affects the reception of the transmitter signal. Alex Lidow has said that by using the GaN chip and new antenna new designs, the AirFuel Alliance managed to build a wireless power supply system with a frequency of 6.78 MHz, which will be able to compete effectively with competitors using low-frequency ranges.
When I joked about asking Nikola Tesla to help in this effort, Lidow commented that he was happy that Nikola Tesla never did get that huge tower functioning to transmit high power across the Earth’s atmospheric layer. I love the work done by Nikola Tesla, but I also believe that this effort was too early for its time and could have been disastrous.
Lidow did comment that we may be able to send a very focused power beam from space one day, but much development work still remains to be done. Last year Japan Space Systems transmitted power over a 50 m distance, but with large losses. Mitsubishi Heavy Industries also managed to send 10kW power over 500m, but with huge transmit/receive arrays. Some day maybe power cables will be obsolete.
1 See my article entitled, Wireless power challenges and opportunities and my article on the 2017 APEC conference entitled APEC 2017: first impressions and observations