Wireless charging promises a cord-free future, one that offers freedom from being tethered to the end of a charging cable. One company might have its finger on the pulse for this wirelessly powered future. Alexander Lidow is the CEO and founder of Efficient Power Conversion, a company looking to expand upon its namesake. EPC most notably displays how it wants to revolutionize wireless charging with a seemingly simple desktop.
Lidow has dedicated most (if not all) of his career invested in finding and normalizing an alternative to silicon. He earned his masters and later Ph.D. in physics from Stanford in the late 1970s with the mission of finding silicon’s replacement. He worked with silicon transistors and developing their effectiveness for decades. Lidow served as Vice President and later CEO of International Rectifier in 1995. He even co-invented the HEXFET power MOSFET transistor.
However, “at the turn of the 21st century, I found myself in a unique position” to develop something new, he said in an interview with Interesting Engineering.
Use of gallium nitride
Initially, he looked to gallium arsenide. Gallium arsenide is an effective semiconductor. It’s used in solar cells, microwave integrated circuits, and certain diodes. While it worked considerably better than silicon transistors, the gallium arsenide was expensive and could really only be used for a niche market.
But then Lidow stumbled upon the effectiveness of gallium nitride. “It was much cheaper and could expand the market,” he said. That gallium nitride FET became the biggest selling point for EPC’s technological innovations — including the wireless desktop.
The real beauty of the system, Lidow hints, isn’t so much the concept of wireless charging but the use of gallium nitride.
“In 2007, I started my own company with this theory that I could make something with a higher performance of silicon with lower cost margins,” Lidow told Interesting Engineering.
EPC mentions on its website that higher performance technologies require higher frequencies to function. Traditional MOSFET (metal-oxide silicon field effect transistors) won’t cut it. But Lidow’s gallium nitride FET could certainly do the trick. That transistor holds the key to EPC’s wireless power success.
As with any tech development, the team experienced its issues. There were the larger issues surrounding wireless power technologies. The biggest one was how to accommodate for multiple objects on the same surface. Each new object meant reconfiguring the resonance to couple the new item. Lidow noted that standards across the discipline helped smooth out those issues. AirFuel Alliance helped to unify certain principles of magnetic resonance to make wireless charging developments easier. Anything else they came across would be more specific to how they applied the technology to the desk.
“When we built our initial desktop using conventional methods, we wanted to do as much as we wanted, as much as it could possibly handle,” he said. “We had to figure out how to get a whole lot more power through it with a bigger amplifier. More power (interference) farther out would whipsaw this antenna around. It wasn’t just nearby it was six feet away. Anything that goes on with it, this antenna starts wobbling around electrically.”
Other objects several feet away (“like a tiny metal belt buckle,” Lidow laughed) could cause interference. Lidow also mentioned that noise became an issue with increasing interference.
The result was an adjusted magnetic field ‘trained’ to stop at the edge of the desk. The field only rises a few inches from the desk top’s surface. Unfortunately, Lidow couldn’t say much else in way of the specifics. EPC is still getting patents on the intellectual property. However, anyone can tell from the demonstrations that it is certainly impressive.
However, Lidow is thinking bigger than just tabletops and kitchen countertops for these antennae. His vision includes drones that charge mid-air. It means TVs hanging on a wall without unsightly cables dangling down. Lidow sees a more environmentally appealing future, one with less batteries and AC adapters.
EPC isn’t the only company working on this technology. The Disney Research group attempted to create a wireless power system covering the entirety of a room. However, Disney recommended users stay at least 46 centimeters away from the point of charge emission — a large pole housing the 15 transistors used. It also powered the various devices anywhere from 40 percent efficiency to 95 percent. Lidow said the EPC wireless desktop comes in between 92 to 93 percent efficiency. That’s roughly equivalent to charging your devices plugged into an outlet without actually needing the outlet and cord.
One of EPC’s wirelessly powered drones that can be charge in mid-air.
“I see a world that’s very different in 10 years,” Ludow said. “I see a house without outlets and extension cords everywhere. Reduced electrical fires because there aren’t as many outlets. Electric autonomous cars will be on the road. When they need more fuel, they’ll stop off at a wireless charging station and get back on the road. It’s simple.”
And as for gallium nitride — that magical semiconductor?
As technology continues to get higher-power and higher-frequency, the chances of that happening become higher as well. The applications go beyond just wireless power. The EPC website lists DC-DC conversion, envelope tracking, and LIDAR as some of the other options for the eGaN FETs. Lidow remains confident that silicon is on its way out.
“I often say ‘as sure as the sun comes up, gallium nitride is going to replace silicon.'”
All images courtesy of Alexander Lidow/EPC