Wireless Power Transmission for Autonomous Sensors in Removable Vehicle Seats

Abstract

Abstract-This work proposes the use of magnetic coupling for powering autonomous sensors in space-constrained applications, such as occupancy and belt detection in removable vehicle seats. The power demand of the autonomous sensor is considered between tens and hundreds of milliwatts. A theoretical analysis first highlights the critical parameters in order to achieve a large powering range and high efficiency. Series-resonant tanks are considered for both the primary and secondary networks. Because the intended application is space-constrained, small coils have to be used. In order to increase their quality factor, commercial ferrite-core coils are used. A class D power amplifier is proposed for the primary network. Experimental results show that a power of tens of milliwatts can be transferred to a 100 Ω load placed at the secondary network up to a distance of 2 cm, near seven times the radius of the coils (3 mm). The addition of a rectifier and a voltage regulator at the secondary network in order to properly power an autonomous sensor (3 V @ 30 mA) limits the powering range to 1 cm. Overall power efficiencies around 45 % and 20 % are achieved respectively at distances of 5 mm and 1 cm.

Seat Occupancy and Belt Detection in Removable Seats via Inductive Coupling

“…The primary and secondary networks may be placed respectively in the car floor and at the bottom of the removable seat. In another paper, we propose to power remotely the secondary network instead [5].…”

Backscattering technique for real‐time monitoring of the received power in wireless power transmission systems

“…Wireless power transmission (WPT) is an effective method of delivering electric power to inaccessible loads in various environments. This method has been used to deliver electric power to sensors, readout circuits, and power storage devices in various biomedical, industrial, and environmental applications . In WPT systems, an electromagnetic field transmits electric power from source to receiver nodes through an electrically nonconductive medium.…”