STM32 MCUs Are Up to the Solar-Car Challenge

Application Examples, Our products, Smart Driving Leave a Comment

The 2016 American Solar Challenge is complete and the winner is the University of Michigan Solar Car team that was sponsored, in part, by ST. The University of Michigan team successfully defended its championship, winning its 6th consecutive title and 9th overall.

The ASC race, run every 2 years, challenges teams to design, build, and drive solar-powered cars in a cross-United States time/distance rally event. This year’s competition, a grueling 8-day, 1,975-mile marathon beginning in Ohio and ending in South Dakota, was further complicated by a lack of power-producing sunshine over the final two days. As a result, only one car was able to successfully complete the race entirely on solar power: the University of Michigan solar car.

There was no secret to the team’s success: the car was exceptionally well designed and both the race and the car’s power were extremely well managed. The extraordinary human achievement was aided by the car’s efficient electronics, which included 6 systems that used STM32F4 ARM® Cortex®-M MCUs. These systems included the lighting boards that controlled the turn signals and driving lights; the system that controlled the steering-wheel functions; a board with a collection of 5 buttons and 10 switches for testing the firmware in the car’s dashboard; and most critically for completing the grueling sun-limited race, the battery-management system board.

According to the UofM Solar Car team, their testing found that the power consumption for the STM32 boards was very low. In fact, the STM32 versions of boards consumed less power than some of the boards they had been running on 8-bit processors in earlier versions of their car.

The UofM isn’t the only solar-car team relying heavily on STM32 MCUs. Another is the Stanford (University) Solar Car team. The Stanford team, which also counts ST among its sponsors, did not participate in the ASC race. This talented team focuses on the World Solar (car) Challenge in Australia (in which the UofM team also participates) and uses the STM32 family of MCUs extensively throughout their car. Among the numerous STM32-controlled functions, there is the car’s Maximum Power Point Tracking controller, which tunes the voltage on the solar cells to maximize output power; another STM32 monitors the power stored in the battery while others control the electrical motors driving the front wheels and perform the driver-control functions.

With the University of Michigan (4th) and Stanford (6th) teams finishing strong in the 2015 World Solar Challenge, both look to build on their successes and the lessons they learned when they compete again in the grueling 3000-km (1864 mile) World Solar Challenge in 2017.

Of course, STM32 MCUs are used for much more than just solar cars – they are the leading family of ARM Cortex-M microcontrollers – and the STM32 Open Development Environment makes it extremely easy to develop and prototype for ANY application.