Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras
A Smart Primary Pad with Integrated TMR Sensors for Wirelessly Charged EVs
Categories for this Invention
Technology: Smart Primary Pad with Integrated TMR Sensors;
Industry & Application: Electric Vehicle (EVs);
Market: The global TMR sensor market is projected to grow at a CAGR of 3.5% during 2024-2029.
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Problem Statement
- In prior art literature survey, it is noted that Wireless power transfer(WPT) using an inductive power transfer (IPT) technique has been finding its application in the EV.
- One of the main challenges faced in the lumped Inductive power transfer (IPT), highway design is the detection of EVs as they travel over the IPT highway.
- Only that primary coil with sufficient coupling with the secondary coil on the EV needs to be energized. To mitigate the above challenge, a suitable sensing mechanism is required. Hence, there is a need to address said issues effectively in efficiently.
Technology
- Present invention describes a simple method and a IPT system to detect EVs’ secondary coil on IPT highways, & further said IPT system enables charging the vehicle while moving on the road.
- The IPT system includes one or more primary coil; secondary coil, installed on a body part of the vehicle; the IPT highway path, one or more sensor are placed over the trailing edge of the primary coil, & the leading edge of the primary coil to measure a magnetic field generated by the detection coil.
The method comprises a few steps shown in the smart chart herein:
- In this instant, a tunneling magnetoresistance (TMR) sensor based EV detection method on an IPT highway is proposed where in a detection coil is wound around an outer boundary of the secondary coil.
- TMR sensors sense the magnetic field generated by the detection coil.
- The TMR sensors are placed over the leading & trailing edges (in the direction of EV travel) of the primary coil, & from the leading edge TMR sensor outputs, the energization point of that primary coil to begin IPT, is decided.
- Similarly, from the trailing edge TMR sensor outputs, the de-energization point to stop IPT from that primary coil, is decided.
Key Features / Value Proposition
Technical Perspective:
- The detection coil is wound around an outer boundary of the secondary coil & the detection coil is excited at 400 kHz.
- The duration of the energizing the primary coil is determined from the TMR sensor outputs, & the duration for which there is an area of overlap between the primary & secondary coils of at least 50%.
- Claimed system enables the driver of the EV in correcting the lateral misalignment so that efficient charging is possible from the subsequent primary pads.
- There was negligible error introduced in the final output due to angular misalignment between the charging lane & the vehicle.
- The sensor system could detect the presence of metallic plates lying on the road in such a way that some of the sensors on the sensor pad are covered.
- The response time was found out to be around 7.5µs & with this response time, the system works for the usual vehicle speeds encountered.
- The proposed system is based on magnetic sensing, its performance is not affected due to dust, snow, oil and humidity.
Industry Perspective:
- Applicable in the area of Electric vehicles, usage in commercial vehicle, Public vehicle & etc.
Questions about this Technology?
Contact For Licensing
sm-marketing@imail.iitm.ac.in
ipoffice2@iitm.ac.in
Research Lab
Prof. Boby George
Department of Electrical Engineering
Intellectual Property
IITM IDF Ref. 2189
IN Patent No: 511503
Technology Readiness Level
TRL-4
 Proof of Concept ready, tested in lab.