Wireless wonder

It’s a bit like charging a mobile phone on a charging pad, except the phone is a heavy vehicle and the pad is the highway beneath it.

The idea was developed by members of the engineering department at Indiana’s Purdue University, who are now testing how well their patent-pending wireless system can provide power to a heavy-duty electric truck, travelling at high speeds.

The electric truck in question, provided by American transport company Cummins, will soon begin driving over the test bed as part of the pilot program.

Semi-trailers with regional routes are ideal candidates for electrification because they travel predictable and consistent distances. However, wired charging, which currently dominates the electric vehicle infrastructure, poses logistical and safety challenges.

To combat this problem, the stationary wireless high-powered charging systems will, ideally, charge heavy-duty vehicles with minimal intervention from fleet workers.

The hope is to electrify a larger section of an Indiana interstate in the next four to five years.

“We’re developing a system that has the power to charge semi-trailers as they move 65 miles (105km) per hour down the road,” said John Haddock, a professor in Purdue’s Lyles School of Civil Engineering.

Within this wireless system, transmitter coils would be installed in dedicated lanes underneath normal concrete pavement and then send power to receiver coils attached to the underside of a vehicle. While other wireless EV charging efforts are also using transmitter and receiver coils, they haven’t been designed for the higher power levels that heavy-duty trucks need.

The Purdue-designed coils accommodate a wider power range — larger vehicles wouldn’t need multiple low-power receiver coils on the trailer to charge from the road, which has been proposed to meet the high-power demands. Instead, in the Purdue design, a single receiver coil assembly is placed under the tractor, greatly simplifying the overall system.

Working with highways and heavy-duty trucks is a unique challenge because the vehicles travel so much faster than on city roads, so they need to be charged at higher power levels.

Building electrified highways with heavy-duty trucks in mind would maximise greenhouse gas reductions and the feasibility of developing infrastructure for EVs.

Heavy-duty trucks are one of the biggest sources of greenhouse gas emissions for the American transportation sector, inpart because they make up a large portion of interstate traffic.

“The so-called ‘middle mile’ of the supply chain, which refers to all the travel heavy-duty trucks have to do to carry goods from one major location to another, is the most challenging part of the transportation sector to decarbonise,” said Purdue Professor of Civil engineering, Nadia Gkritza. “We see the potential for dynamic wireless power pavement technology as complementary to an expanding network of EV charging stations that we will see very soon here in the US.”