Forget dirty cables lying around on the floor and brutal connection to charge your car, the future is in induction, especially with this technology which eliminates the few defects.
Researchers at Chalmers University in Sweden have developed an induction technology that can achieve near perfect efficiency with loads climbing up to 500kW of power, putting it on par with today’s best solutions by cable. The team ensures that the project is so successful that it could be produced and marketed shortly, a passage facilitated by the use of already existing components.
Components already available
Professor Yujing Liu, in charge of the project in the Department of Electrical Engineering at Chalmers, explains the reasons for this spectacular result: “One of the key elements is that we now have access to high-power semiconductors based on carbide. silicon that have only been on the market for a few years. They allow us to have a higher voltage, higher temperatures and a much higher switching frequency compared to conventional components”.
The frequency of the magnetic field is crucial since it determines the limit of the power that can be transferred between two coils. Current induction systems generally operate at frequencies around 20 kHz, which is close to what is observed on a cook. Yujing Liu’s team works at 80 kHz. However, the more the frequency increases, the more the power dissipated by Joule effect causes the temperature to explode. To reduce this problem, they therefore need to use coils made up of Litz wires, each made up of 10,000 copper strands 70 to 100 micrometers thick, like a hair, woven and electrically insulated from each other. Again, these yarns were not commercially available until a few years ago.
Only 1 to 2% loss!
One of the factors limiting induction charging so far has also been the excessive losses which can be up to 50% on conventional systems. Here, Professor Liu is formal: we are of the order of negligible, between 1 and 2%.
The next step will therefore be to commercialize this technology. But it’s not tomorrow that you will have it in your box to load your personal vehicle. Yujing Liu himself, who drives an electric car every day, does not see much use in it: “I go home, I plug in and there you go, there is no problem”. Rather, the research team primarily has an industrial and professional application in view, for example in the charging of trucks or ferries.
