Magnetic induction currently has the wireless charging market cornered and is available in Google, Samsung, and Nokia devices. Induction typically uses two magnetic coils -- a primary wire coil with an alternating electromagnetic field from within a charging base station, and a secondary coil in the device to convert power from the electromagnetic field to electrical current to charge a battery. Together, the coils create a transformer.
"If you design it right -- the right frequency and material, the quality of that coil -- you can get very efficient power transfer and design for specific distance or power," Perzow said.
Several companies have taken to inductive charging. Samsung's Galaxy S4 supports Qi, as has Google and Nokia. Perzow said the WPC has more than 40 million wireless devices on the market and has support from the semiconductor industry, Ikea, and Verizon.
The WPC offers close coil inductive technology, which draws up to five Watts and operate at 200-300 kHz. Perzow said the WPC's Qi technology can extend the charging range up to 40 mm away from the power source with 70% power efficiency.
ConvenientPower's dual-mode inductive/resonance multi-device charger.
(Source: WPC blog)
Qi and inductive charging have been touted for having protected connections, being safe enough for medical devices, and harboring low radio frequency interference. However, inductive charging is accused of being more delicate and more inconvenient than other types of charging; users have little freedom and must line up a device precisely with a wireless charging pad.
"I think there's something to that, but the assumption is that Qi is close couple inductive, and it will be that way forever, and that's not the case," Perzow said. "It is a constantly evolving technology. Qi is not a product. You can't spec it."