Partnership with Renesas Electronics for the optimization of inductive position sensors

Renesas Electronics America (REA) is one of the biggest players in the inductive position sensing world after the acquisition of Integrated Devices Technology (IDT) Inc. in San Jose, California, during 2019.

REA and EMC Gems team have a long standing collaboration about the improvement of the accuracy of inductive position sensors, that are used in many industrial devices, from household appliances to robotics and automotive applications.

REA produces, among many other things, a family of integrated circuits for the realization of position sensors. This type of sensors is based on the physical principle of electromagnetic induction and its main strengths with respect to other technologies are its low cost and high immunity to stray electromagnetic fields. The use of these sensors is gaining popularity only recently in the industrial and automotive markets because the accuracy in the position obtained with this technology was not similar to that obtainable with other technologies.

In the first phase of the collaboration, we tailored our solvers to solve the eddy current problem coupled with mechanical motion that are typical of the virtual prototyping of inductive position sensors. In particular, the most efficient code is an optimized version of the Boundary Integral Method (BIM) code [1]. The typical electromagnetic simulation for the characterization of an inductive position sensor takes a few minutes. The simulation consists in finding the eddy currents inside the target and estimate the voltages induced on the receiving coils.

After the electromagnetic modeling tool was validated by REA with measurements on physical prototypes, EMC Gems team developed a novel methodology for inductive position sensor optimization. Optimization means in this case to obtain an inductive position sensor design that offers the best linearity measurement error and the least mismatch in the sin and cos receiving coil voltages. Differently from other techniques proposed in literature, it is the first time that the optimization is performed by modifying the shape of the sin and cos receiving coils. The optimization of the coil shapes is performed automatically and efficiently with EMC Gems virtual prototyping tools. The whole optimization is typically performed in about half an hour. The results obtained on physical prototypes showed that the methodology we developed allows to significantly improve the performance of the sensors designed by REA. A patent of the methodology has been granted [2].

We are looking forward to new collaborations and challenges in the field of inductive position sensors.