Synchronized Switch Harvesting Technique Applied to Electromagnetic Vibrations Harvester

1. Synchronized Switch Harvesting Technique Applied to Electromagnetic Vibrations Harvester E. Arroyo, A. Badel, F. Formosa Contact : earro@univ-savoie.fr Low voltage level Objectives Model of an electromagneticgenerator Vibrations Optimization of the electrical extraction circuit for electromagnetic generators Mechanical Energy ( Vibrations ) Mech.-to-mech. conversion Mechanical energy inside the gene. Application of non-linear techniques developed for piezoelectric generators to electromagnetic generators Energy harvester Mech.-to-elec. conversion Non usable electrical energy Electrical extraction circuit Usable electrical energy Comparison with classical extraction technique - Minimal losses Only 3 parameters are required to describe the behaviour of an electromagnetic generator - Highest possible power - Usable DC voltage levels Experimentation - Large bandwidth Autonomous sensor node MICA 2 (Berkeley) - Self-supply of the circuit SMFE circuit Classical extraction circuit Models Charge of C1 T/2 T Simplified linear model Commutation at each extremum of current Charge of C2 P overestimated Charge of C1 or C2 Simulations For low ξe : PR: Harvested power with the classical technique, with matching impedance Same or more power extractedwith the SMFE technique Best case : 2.5 more power PSMFE: Harvested power with the SMFE technique For high ξe : Less power extractedwith the SMFE technique Worse case : 10% less Experiments Performed on a non optimized generator PR strongly dependent on the load PSMFE constant from R = 1kΩ Generator parameters: k²= 0.03% ξe = 1 AC voltage level < 0.2V Resonance frequency : 153 Hz + Rectifier Usable DC voltage Usually increased by increasing the number of turns of the coil, at the detriment of the energy density From 1 to 30 V