Intelligent sensor systems for automotive applications

The growing market of high performance electric vehicles requires the development of compact electric motors able to deliver high torque and power with maximum efficiency. Performance, as well as the reliability, are two key parameters for a manufacturer. The monitoring of permanent magnet temperature and bearing health monitoring are among the most relevant technical aspects. In the first part of this thesis the state of the art analysis has been described, highlighting the technical difficulties of temperature measurement on the rotor of a high performance electric motor with high rotational speed. The collaboration between the HPE Group and the University of Bologna allowed the realization of four prototypes that have demonstrated the feasibility of the permanent magnet temperature monitoring with a contact type sensor at high rotational speed. The development, manufacturing and test of these prototypes has been illustrated together with the advantages and drawbacks analysis for each solution. The flow of the development has been focused on a progressive evolution towards solving the main problems that prevent this type of acquisition system from accessing the mass market. In particular, the two main issues to be solved are the cost and the invasiveness. The hardware evolutions achieved made it possible to obtain a final prototype that has the potential to be produced on a large scale. In addition, the solutions developed are also an important contribution to the existing scientific work, especially for what concerns the work on non-invasiveness and reliability at high rotational speeds. Finally, there is a brief description of a tailor made PCB solution for bearing monitoring through the vibration analysis. The developed prototype has been installed on a real high performance electric motor. Furthermore a dedicated test bench, capable of emulating some of the main causes of bearing failures in electric motors, has been presented.