Magnetically-driven triboelectric generator as a direct power source for wireless sensors

This paper describes a magnetically-driven rotating triboelectric generator (M-TEG) as a direct power source for wireless sensors. Four M-TEGs are symmetrically placed on the wheel hub of a vehicle. Permanent magnets mounted on the brake caliper provide a non-contact magnetic force to generate a seesaw-like swing motion of the M-TEG in the tire. The unique advantage of the seesaw structure eliminates the influence of a large centrifugal force at a high rotating speed. High electrical output has been achieved in the wide ranges of rotation speed. The M-TEG at the rotation speed of 100 rpm can deliver a maximal output voltage of 316 V and power of 22.3 mW under a constant magnetic field strength of 0.2 T. There is no obvious decrease in the output voltage of the M-TEG after continuous working for more than 12 h. The power generated by the TEG is stored in a capacitor and the stored energy is used to drive MEMS pressure sensor. The M-TEG has also demonstrated to power a commercial wireless sensor for sending the real-time temperature information to a receiver and displaying on a monitor.