researchers of the Chalmers University of Technology (Sweden) have developed an induction charging technology capable of reaching 500 kW of power in direct current, as well as offering an efficiency of 98%. The team behind this breakthrough says the new system will soon be presented to the industry for commercialization.
The teacher yujing liu, who is leading the project at Chalmers Electrical Engineering Department, says that in terms of performance, it is one of the most efficient wireless charging systems in its power range. The researchers have used already existing components, which explains why this technology is practically ready to reach the market.
“A key factor is that we now have access to high-power semiconductors based on Silicium carbide, the so-called SiC components. They allow us to use a higher voltage, a higher temperature, and a much higher switching frequency, compared to classical silicon-based components.”
“Previous systems for wireless vehicle charging have used frequencies around 20 kHz. They were bulky and the energy transfer was not very efficient. Now we work with four times higher frequencies. So, induction becomes more attractive». The frequency of the magnetic field sets the limit on the amount of energy that can be transferred between two coils.
An ideal solution for electric buses
Another recent advance that has been able to be incorporated is the coils made of twisted “copper cords”made up of up to 10,000 copper fibers (each between 70 and 100 micrometers thick).
Regarding the efficiency of almost 100% of this technology, Yujing Liu points out that “Losses occur either with conventional conductive charging or with inductive charging. The efficiency we have now achieved means that losses in inductive charging can be almost as low as in a conductive charging system. The difference is so small that in practice it is negligible, around 1% or 2%.
The solution developed by Chalmers is powerful enough to charge buses extremely quickly without the need for human or robotic intervention. “It can facilitate the electrification of large vehicles and therefore speed up the phasing out of, for example, diesel-powered models.” Interestingly, Yujing Liu doesn’t think it will be especially useful for electric passenger cars.