Many researchers foresee a future where owners and drivers of electric vehicles don’t need to search for charging stations and spend time parked to top off the batteries. Someday in the future, charging your EV to be done by simply driving in the correct lane. The researchers are investigating technology that could recharge vehicle batteries by driving over special charging strips embedded in the road.
The sort of technology would save time for drivers and improve productivity in warehouses. Cornell researcher Khurram Afridi says there are many infrastructure questions you have to ask when trying to switch an entire country to electric vehicles. He says how society would function is a significant question because changing drivers en mass to electric vehicles means we need lots of charging outlets.
Afridi says we don’t have the kind of power available in our homes to charge vehicles very quickly. The approach the Cornell team is taking has origins more than a century ago, with Nikola Tesla famous for using alternating electric fields to power lamps, among other things. Afridi and his team say wireless power transfer is based on the underlying physics used to send messages through radio waves to spacecraft in deep space.
He says one significant change is that they’re sending much more energy across much shorter distances to moving vehicles. The system the team designed uses two insulated metal plates on the ground connected to a power line through a matching network and a high-frequency inverter. They create oscillating electric fields that attract and repel charges in a pair of matching metal plates attached to the vehicle’s underside.
The plates drive a high-frequency current through a circuit on the vehicle that rectifies it, and the rectified current charges the battery. A significant advantage of electric fields is that they have a more linear and directed nature compared with looping arcs of magnetic fields. That means they don’t require flux-guiding materials like ferrite and can operate at much higher frequencies.
One big challenge now is that electric fields generated by readily available voltages are weak. The team is compensating for the weakness by boosting voltage and operating the system at very high frequencies to achieve large levels of power transfer. The team is currently working to refine their system.