Improved Functional Safety and Control Features of Sensorless Controlled Traction Drives by Adapted Machine Design (ATEM Sensorless)

Sensing the rotor position of tracton drives in electric cars by means of conventional position transducers increases the volume of the electric drive and poses a potential source of error. A failure can lead to power train damage or even to loss of controllability of the car. Reliability and thus functional safety can be increased by using sensorless methods as a redundant system.

For sensorless operation at low speeds, special demands have to be met when dimensioning and designing an electric drive. The realisation of a suitable motor design has not been explored sufficiently yet. In this project, a global approach in considering machine design and control shall develop a practice-oriented and flexible methodology for the design of traction drives, meeting the requirements made on sensorless operation and system performance.

Using a combination of numerical and analytical machine calculation methods and control simulations, the correlations between machine design and the influences on sensorless control are investigated and expressed in terms of design rules. The results are integrated in a novel, flexible development methodology, considering all relevant optimisation criteria of the drive system. The advantages and the suitability of the approach shall also be verified by practical experiments on standard motors and on a demonstrator.