E-Machine Test Benches

  Picture of an e-machine test bench with a testing person in front of it. Copyright: © RWTH Aachen | TME

The laboratory for electric machines of the Center for Mobile Propulsion allows testing of various electric motors and generators e.g. for traction motors or Range Extender applications. The test bench is equipped with a powerful three-phase asynchronous load machine working as brake or drive unit, extensive measurement technology, a digital power analyzer for measuring of alternating current, in short AC and direct current, in short DC currents, a flexible IPU (Inverter Power Unit) and a coolant supply.

The flexible IPU can be used for characterization of different electric machines under steady state conditions. The temperature of the test object can be varied in a wide range by external conditioning of the cooling medium. In such tests, the losses and the thermal behavior of electric motors can be analyzed in detail. Additional possible types of testing are for example a back EMF analysis and a performance and efficiency measurement.

In addition, it is also possible to couple the traction machine with a hardware-in-the-loop, HiL simulator for short. This so-called closed-loop operation makes it possible to simulate the environment of the traction machine under hard real-time conditions and to take into account interactions with neighboring components - transmission, battery, DC/DC converter, combustion engine - during test bench operation. Thus, real traction machines are tested in a virtual hybrid drive to verify the hybrid strategy already in early development phases. In further test scenarios, the entire vehicle is simulated and the influence of the thermal e-machine behaviour on the driving dynamics is investigated, taking into account safety-relevant driving functions, e.g. torque vectoring.



Load machine
  • Asynchronous induction machine 271 kW peak, 200 kW const.
  • Torque: 601 Nm peak, 441 Nm const.
  • max. Speed: 14770 rpm
Power supply
  • max. voltage: 800 V DC
  • max. current: -400 A ... +400 A
  • Power: 270 kW peak, 200 kW const.
Coolant supply
Coolant conditioning -30 ... +105 °C