Utah State University "Aggie Bus," using wireless charging up to 90% efficient. (via Utah State University)
One of the biggest problems with switching to electric public transit buses is the issue of long-lasting, reliable batteries that last throughout the day and night. This dilemma has been tackled and researchers at the Utah State University in Logan, Utah, have obtained a solution. Their invention, called the “Aggie Bus”, will be tested on the USU students in 2013.
The bus overcomes battery issues by using inductive charging at bus stops. An inductive charging transformer, which consists of flat coils of wire, is split up. One half is placed on the underside of a bus and connects to its batteries. The other half is embedded in the street so the bus can be charged as it sits atop predetermined stops.
16 months ago, USU announced they had developed an induction charging system suitable for automotive vehicles. Using Nikola Tesla’s principles of induction, professor and engineer Hunter Wu applied modern technology to develop this method of charging. The USU team has worked with the Advanced Transportation Institute, an initiative of Utah Science Technology and Research (USTAR), to develop the “Aggie Bus”.
Their work has produced notable innovations in the field of wireless power transfer (WPT). First, they have pushed the maximum power that can be transferred to 25 kW. The team has achieved a transfer efficiency of 90%, though some reports say this high efficiency applies to 5 kW transfers and is much lower when transferring 25 kW. Another big hurdle towards public application was cleared when the team achieved a system that still charges even when the bus and charging pad are misaligned, up to 6 inches.
As Robert Behunin, USU’s Vice President of Commercialization and Regional Development, said, this technology offers many benefits past convenience. First, the batteries required are much smaller which saves money and space and reduces weight. Obviously, charging time can be reduced or eliminated using induction at each bus stop. The USU system includes no moving parts, which lends for greater reliability and requires no contact for conduction or visible wiring, so there is little risk for electrocution.
Although this is the first induction bus to be developed and designed by North American organizations, Italy, Korea and the Netherlands are testing similar projects.
The Aggie Bus was developed and will be sold by the USU spin-off company WAVE (Wireless Advanced Vehicle Electrification) Inc. WAVE will produce both halves of the induction chargers and will also likely oversee their installation and maintenance. WAVE will share revenues with USU and vice versa (WAVE has already paid the university $17,000 as royalty for their research). They will have ready-to-use buses in 2013 and will focus on replacing those that use overhead catenary wires to run (like electric trains). The company plans to be competitive with diesel and compressed natural gas vehicles.
An Aggie bus is already being tested on the streets, but in the summer of 2013, a 40’ Aggie bus will debut on the USU campus. This bus will use next generation inductive charging transformers capable of delivering 50 kW of power. This project has received $2.7 million by a TIGGER grant from the Federal Transit Administration.
Now we just need to combine this method of charging with many other possible ways of generating electricity. I think WPT buses and speed bump generators would make a perfect match.
Cabe
