Abstract
Energy harvesting (EH) for tire pressure monitoring systems (TPMSs) is a key element to make tire sensors self-sufficient and to raise the features of vehicle tires to a next level. This work studies the commercially available piezoelectric flat transducers M2807-P1, M2807-P2 from SmartMaterials and P878.A1 and P876.SP1 from PI Ceramics to use the tire strain and to generate electrical energy inside the tire. An equivalent electromechanical network with the strain as input signal is derived and used to predict the voltage at the harvester output. A 220 μF capacitor is connected to store the harvested energy. In contrast to the common use of full-wave rectifiers, this work uses a synchronous electric charge extraction (SECE) circuit for efficient energy transfer. An electronic breaker (EB) serves as a simple implementation with discrete components. Although an EB provides only an efficiency of 40 %, it increases the amount of transferred energy significantly compared to state-of-the-art TPMS systems. Experimental results show an increase of the harvested energy of more than 200 % compared to former works.
