Drives and Controls Magazine

Electric sportscars use Siemens drivetrains

02 March, 2009

Researchers at Siemens have developed the drive-train technology for two electric sportscar prototypes unveiled at the recent Geneva Motor Show.

The first was a battery-powered version of the Porsche 911 developed by the German high-performance car specialist, Ruf Automotive. The prototype has a 270kW, 950Nm motor, a range of around 200km, and reaches 60mph (96km/h) in less than seven seconds. The electric 911 could go on sale next year.

A later version is expected to use two motors and to be the world’s first electric car with a bidirectional mains connection. This will allow it to be recharged in two hours from a 400V supply without needing the extra circuitry usually needed for charging. It could even feed excess energy into the grid.

The second Siemens-powered car at Geneva was a concept vehicle from the Swiss developer Rinspeed which can be converted from a one-seater sportscar to a three-seater using a flexible roof. This car, called the iChange, is powered by a 150kW motor and takes 4.2s to reach 100km/h. Its top speed is said to be 230km/h, and its pricetag is likely to be around  €1m.

The Siemens drivetrain for these cars consists of a motor/generator, power electronics, and a battery interface. The company says that the “electromobility” activities currently based at its corporate technology centre could join its environmental portfolio, which generated sales worth €19bn last year.

Siemens is also involved in other aspects of electrically powered road transport, including a project to develop and standardise charging technologies for electric and plug-in hybrid vehicles. One idea is to use the large batteries in these vehicles to store energy when they are not on the road. It is estimated that 90% of vehicles are idle for long periods and could therefore act as a distributed energy stores using birectional energy transfer systems, such as the one planned for the Ruf sportscar.