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University of Minnesota

Solar Vehicle Project

Sponsors of the
Solar Vehicle Project

Electrical Engineering's Senior Design Class
Works on Projects for Aurora-II Team

As part of our curriculum integration, students from the Electrical Engineering department's senior design course will tackle two projects for the Aurora-II team.

The first project is to design a smart battery charger to charge our our donated battery pack. The smart battery charger will be used to recharge our 84 Volt battery pack during testing of the motor, the controller and Aurora-II itself.

Most batteries like to charge with a constant current, but most battery chargers are designed to charge at a constant voltage. This charging method reduces the lifetime of a battery. The battery charger researched by the design group will utilize switch mode electronics to charge with the batteries' preferred profile.

The second project is to have students design a manufacturable electric wheel. An electric wheel is really an electric DC brushless motor. The electric wheel takes the place of the drive wheel and attaches at the suspension mount point, and the rim of the drive tire.

The basic concept of this system is to turn a motor inside out. The suspension arm connects to the shaft, which remains

stationary. The shell of the motor with the rim and tire attached, rotates around the shaft and propels the vehicle. Typically on an electric vehicle, a motor with a gear attached to the shaft turns a belt connected to another gear on the wheel.

The electric wheel design would eliminate belt drag, reduce the overall weight of the vehicle, and eliminate need for belt and gear maintenance.

By replacing the vehicle's transmission system with this electric motor we can remove the inefficiencies of the transmission system, and be left with only the electrical losses associated with the motor. The addition of the electric wheel would greatly increase the range of Aurora-II since the efficiency of power from the battery pack to the ground would is 10 - 15 percent higher than with a motor/controller and transmission system.

The end result of our relationship with the EE senior design class will be two prototypes that we can begin to construct shortly.

Alex Detrick

Lights,
Camera,
Action!

Marketing Team
shifts focus to secure
media coverage of the
Aurora-II

We hope to have behind-the-scenes coverage of the buildup to

the unveiling of Aurora-II as well as coverage of the unveiling itself. We hope that the media will also broadcast pertinent updates of Aurora-II during the race.

In addition to news coverage, a local company is interested in producing a documentary about the Solar Vehicle Project and its team members. The documentary will cover the production of Aurora-II, Sunrayce 95 and the Pikes Peak Hill Climb. The documentary will also show what students can do in the "real world" with a post-secondary education in engineering.