Audi has presented the new e-tron FE07 that has been developed by Audi Sport, with a new Audi MGU05 motor-generator unit. The electric racing car, with an all-new electric powertrain that was developed in-house for the first time, will make its debut on the race track during the test in Valencia.

While in recent years a continually optimized version of the powertrain, jointly developed with technology partner Schaeffler, was always used, work on the new MGU inverter unit for the coming world championship started from scratch.

The result is the Audi MGU05: an electric one-speed drivetrain with an internal rotor concept, external magnets, a highly efficient cooling system and six electrical phases. The engineers led by Stefan Aicher, Head of Development e-Drive at Audi Sport, managed to save weight compared to the previous unit by using lightweight materials and intelligent integration inside the vehicle.

We were able to directly reinvest these savings in the new MGU for the benefit of enhanced efficiency. Even so, the new MGU inverter unit weighs less than 35 kilograms. This was an exceptional achievement by the whole team.

—Stefan Aicher

Efficiency is the key factor of success in Formula E. In numerous tough testing cycles, the entire powertrain was stressed to its limits in order to raise the entire high-voltage system to a maximum performance level. The outcome was successful, with an overall efficiency of more than 95% for the powertrain. The new MGU inverter unit has an efficiency of even more than 97% in all relevant driving conditions, said Tristan Summerscale, Formula E Project Leader at Audi Sport.

If you compare our MGU with an internal combustion engine delivering a comparable power output of 250 kW, our efficiency is not only twice as high, but our weight of less than 35 kilograms is also much lighter. This clearly shows what an efficient solution an electric powertrain is.

—Tristan Summerscale