National | CHUBU CONNECTION

Nobel winner Hiroshi Amano and his team tap gallium nitride technology in bid to transmit power wirelessly from a distance

Chunichi Shimbun

Hiroshi Amano, a professor from Nagoya University who was awarded the 2014 Nobel Prize in physics, is developing together with other researchers a remote power supply system that sends energy to distant places using electromagnetic waves.

If put into practical use the research could greatly benefit all of society, such as through recharging electric vehicles (EV) while they are running or sending solar power generated in space to the earth.

“Our first target is to create a wireless system to supply electricity to drones within three years,” Amano said.

Currently, wires and cables must be connected to an electrical device to supply energy so that it can run continuously. Some wireless power transmission technology is already available, but it is inefficient and limited to products that can run on low power such as mobile phones.

The research team aims to develop a system that can convert electricity into high-frequency electromagnetic waves that are then sent to the target destination, like a laser light from an antenna, and converted back to electricity via a receiving antenna.

Theoretically it is possible to send a large amount of electricity to a distant place efficiently, but it is difficult to put the idea to practical use with current technology as a lot of energy is lost in the process.

Amano, 57, and his team have utilized the technology of crystallizing gallium nitride (GaN) — which was key to developing the blue light-emitting diodes (LED) that won Amano his Nobel Prize — becoming the first in the world to successfully improve the performance of power semiconductors used to regulate voltage and electric current. They believe this will contribute to resolving issues such as power loss.

The team has begun by developing a system for drones. With the cooperation of Japanese electronic manufacturers and drone developers, they are currently building a system with an electric circuit and embedded antenna.

The first target is to build within the next three years a system that can transfer energy wirelessly over a short distance — of a few dozen centimeters — in three minutes.

After that, they hope to develop it further so the system becomes able to charge a drone that can fly approximately 100 meters high.

“Remote power supplies will revolutionize the way goods and people are transported. They can enrich our lives,” said Amano.

Since drones can fly across areas regardless of geographical features, they have gained attention as a useful tool in disaster rescue missions and as a next-generation alternative for distributing goods.

However, they can only fly for a short period of time and need to be recharged frequently. A standard drone that is carrying an object weighing 20 kg can only fly for about 30 minutes.

If drones can be recharged while flying using a remote power supply system, their flight time will become virtually unlimited.

Manufacturers around the world are also competing to improve the performance of electric vehicles, where the new technology could again offer benefits.

One of the shortcomings of EVs is the long period of time needed for them to recharge. However, if remote power supply systems are installed on the road or intersections vehicles could recharge while running, so drivers would not have to stop at recharging stations.

Competition around the world to develop wireless power transmission technology is growing increasingly fierce.

The most well-known method is the magnetic coupling method, written in a paper published by Massachusetts Institute of Technology in 2007, but this method basically covers only short distances.

The system Amano and his team aim to build will enable the supply of power by sending electromagnetic waves to remote islands and other places, as well as transmitting electricity from offshore wind power efficiently to cities.

In the future, it may even be possible to build a space solar power plant whereby electricity generated in solar panels that are floating in space would be sent to Earth.

The development of the blue LED was a revolution in lighting technology, following the invention of incandescent bulbs and fluorescent lamps.

“I believe that (the remote power supply system) will become the technology that can make a greater contribution than the blue LED to the well-being of people all over the world,” said Amano.

This section, appearing Tuesdays, features topics and issues from the Chubu region covered by the Chunichi Shimbun. The original article was published on Jan. 4.