Dr Jeshma Thalapil Vaheeda

An easy-to-fabricate, full circle range (0◦-360◦), planar coil-based variable reluctance (VR) angle transducer with enhanced linearity is presented in this paper. The proposed sensor system aims to mitigate the limitations of existing VR angle sensors, particularly their limited accuracy and nonlinearity, resulting from the inherent sensor output characteristics. By carefully designing the coil geometry to achieve uniform flux distribution and implementing a simple semicircular-shaped rotor, the sensor system offers enhanced performance and linearity. The proposed sensor employs a semi-circular-shaped rotor plate (RP) placed between two PCBs with four coils each. These coils are strategically designed to ensure a linear variation of inductance with respect to the RP position, resulting in improved linearity in the sensor output. After validating the sensor design through analytical methods and finite element analysis (FEA), a suitable algorithm was developed for accurately estimating the rotor angle. A sensor prototype was manufactured to evaluate the performance of the sensor system. The prototype showed an excellent linearity with a worst case error of 0.31% and a resolution of 0.11◦. The sensor shows negligible sensitivity to axial misalignment of the shaft and the presence of external magnetic objects, highlighting the practical usefulness of the system.

This article presents a sensing system in the vehicle pad that detects the ground pad type and helps to enable the vehicle-to-grid (V2G) operation of an electric vehicle (EV). In this work, two commonly used vehicle pad types, i.e., circular pad (CP) and double-D pad (DDP), are considered together with bipolar pad (BPP) ground pad. BPP has to be correctly configured to magnetically couple to CP or DDP type pads in the EV. Otherwise, the efficiency of V2G wireless power transfer (WPT) will be very low. It will be highly beneficial if a simple scheme is available that can independently sense the ground pad configuration from the vehicle side. The proposed system senses the change in the magnitude and spatial pattern of the magnetic field directly below the vehicle pad and reliably detects the ground pad and senses the configuration of it. During sensing, the vehicle pad is excited at a very low current at the resonance frequency of the pad, and the magnetic field is observed using magnetoresistance (MR) sensors integrated in the vehicle pad. The magnitude of the field changes, mainly, due to the frequency bifurcation effect (FBE), while the field pattern gets modified due to the induced current in the ground pad. A prototype of the proposed system was built in the laboratory and tested, and its performance was evaluated. The results showed that the BPP ground pad configuration can be reliably sensed from the vehicle side, for both CP and DDP types of vehicle pads, thus validating the functionality and practicality of the proposed approach and the sensing system.