Scientists at the North Carolina State University have developed a particularly small and efficient fast charger for electric cars. Their so-called medium voltage fast charger (MVFC) combines a transformer and charger in one for charging with 50 kW and great efficiency.
In fact, the team from North Carolina State claim their compact charger has reached an efficiency of 97.5 percent. This means their medium voltage fast charger disposes over an additional 4.5 percent power, power that goes to waste as heat when using a conventional charger.
Moreover, they claim their charger to be ten times smaller and much lighter than existing chargers today. The MVFC weights just 50 kilos and can be wallmounted whereas conventional 50 kW chargers require a concrete slap to hold the transformer alone. Srdjan Lukic, associate professor of electrical engineering at NC State and one of the developers explains: “The MVFC does the work of both the transformer and the fast charger, taking power directly from a medium-voltage utility line and converting it for use in an electric vehicle battery.” Another reason why the researchers were able to downsize the technology was the use of wide bandgap semiconductor devices.
From here, they started developing a new version of their compact charging device, this time with quicker charging and taking more than one electric vehicle into account. “We’ve had the more powerful, multi-vehicle MVFC in mind for some time, and recently received funding from the Department of Energy to build a next-generation prototype,” says Lukic.
In the multi-port station design, reads a release, a utility line is connected directly to a solid-state transformer (SST), which is a power-electronics-based smart transformer. The SST then feeds a local DC micro-grid, including stationary battery storage systems so that multiple charging points can be served. The multi-port MVFC will have a rating capacity of one megawatt, with each charging node capable of providing up to 350 kW of power, meaning the researchers are aiming for high power charging territory here.
The team is currently looking for industry partners to commercialise their technology.