Postgraduate Projects

Postgraduate studies (PhD) of graduates are presently done at Austrian and European partner universities. In course of these studies, research projects are carried out at Carinthia University of Applied Sciences.

HALL-SENSOR-IC (2003 - 2006)

Development of a Signal Processing Unit for the Position Detection of Rotating Objects Using Magnetic Field Sensors

In the automotive area magnetic field sensors are commonly applied for the position detection of rotating objects. One field of application of such a detection system is the angle detection of crankshaft and camshaft. In this Area the demands are correct phase and air gap independent signal output. Of course the sensor chip should also be very robust to noise and work without errors.

Figure 1 shows the application of a camshaft sensor: the differential sensor chip (there are two identically hall elements integrated into the chip) measures the magnetic field of the bar magnet behind the chip.

Figure 1: camshaft wheel with differential Sensor

The asymmetry of the magnetic field in between bar magnet and cogwheel, which depends on the actual cogwheel position, generates different hall voltages in the two sensor elements: the voltage is high if a cog is ahead the sensor and vice versa.

The aim of this PhD Thesis is to develop a digital signal processor (DSP) unit that detects the angle of the cog wheel from the differential sensor signal shown in figure 2. To perform minimal phase error and air gap independency nowadays sensors use different hysteresis concepts. The new sensor architecture will approach the problem from an other point of view with more complex and advanced algorithms.

Figure 2: Sensor Signal with wanted output after DSP

 

Publications

S. Hainz, E. Ofner, D. Hammerschmidt, T. Werth, H. Grünbacher: "Position Detection in Automotive Application by Adaptive Inter Symbol Interference Removal", in Proc. IEEE Sensors 2006, Daegu, Korea.

S. Hainz, D. Hammerschmidt, E. Ofner, T. Werth: "Improving Phase Accuracy by Removing Systematic Phase Error Introduced by Inter Symbol Interference", in Proc. Eurosensor 2006, Göteborg, Sweden.

S. Hainz, E. Ofner, D. Hammerschmidt, D. Tatschl and T. Werth: "Data Predictive Decisoin Feedback Equalizer for Position Detection in Automotive applications", in Proc. ICIT 2004, Hammamet, Tunisia.

S. Hainz, E. Ofner, D. Hammerschmidt, D. Tatschl and T. Werth: "Position Detection by Inter Symbol Interference Removal for Engine Applications", in Proc. Austrochip 2004, Vienna.

 

Project Partner

This project was done in cooperation with Infineon Technologies Villach, Department for Advanced Sensors.