Engineers from Stanford University have presented a new technology that can wirelessly recharge devices while they are in motion. This technology could theoretically be scaled up so that drivers could charge their cars without ever having to pull over.
“This is a significant step toward a practical and efficient system for wirelessly re-charging automobiles and robots, even when they are moving at high speeds. We would have to scale up the power to recharge a moving car, but I don’t think that’s a serious roadblock. For re-charging robots, we’re already within the range of practical usefulness.”Shanhui Fan, professor of electrical engineering, director of the Edward L. Ginzton Laboratory, senior fellow at the Precourt Institute for Energy and professor, by courtesy, of applied physics.
Traditionally, wireless chargers work by creating a magnetic field with an oscillating frequency. This frequency creates a vibration within the magnetic coils found on the receiving device, resulting in the charger wirelessly transmitting energy. Unfortunately, the resonant frequency alters once the distance between the devices changes.
To deal with this issue, engineers added an amplifier and feedback resistor to their system. This gave their system the ability to automatically adjust as the distance between the two devices. The amplifier currently used in their design is a switch mode amplifier that boosts the efficiency of the system by 92%.
The latest prototype of their system has the power to transmit 10 watts of electricity wireless for up to two or three feet. The engineers are confident that scaling up the system so it can be used with cars, drones, and robots, should pose no problem. The greatest concern, according to the team behind this system, is whether the batteries in electric cars will be able to absorb so much power.
Although this is an exciting development to be sure, it will likely be many years before this technology is implemented. The wireless chargers will have to be thoroughly tested before they are embedded in highways around the country. That being said, this is a promising step towards a reality where you can recharge your car on the go, wherever you may be heading.
I did a work for similar applications during my PhD a couple of years ago.
If you wish to read it, it is open access at: https://ieeexplore.ieee.org/abstract/document/8125727