Stephan Paul, Bernd Cebulski, IAV GmbH Germany
The torque generated in automotive drives has to satisfy strong requirements regarding dynamic behaviour and accuracy. The state-of-the-art solution to realise the requirements is to implement a field-oriented-control (FOC). But this control needs to have accurate information about the current position and / or the current speed of the rotor. To acquire these information rotor-position-sensors are used that have an electro-magnetic-working principle. Usually these sensor are located close to the winding heads of the stator- and rotor-windings due to limited space for installation. Distortion of the sensor-signals can occur due to the electro-magnetic stray-field of the winding heads and the accuracy of the control gets worse. To avoid these problems and to implement the suitable sensor it is important to know exactly the spatial and temporal distribution of the electromagnetic field within the end-space.
These effects are investigated closely using different kind of approaches. The first one is the analytical calculation using the Biot-Savarts law. The second approach is the full 3D-FEM-Simulation using JMAG. Finally the calculation- und simulation-results are compared to 3D-measurements of the flux-densities inside an induction machine operated in different load-points.