An Electromagnetic Speed Bump Energy Harvester and Its Interactions With Vehicles

A novel speed bump energy harvester (SBH) is designed, developed, and tested to harness electricity energy from impulsion excitation when a vehicle passes through a speed bump. The challenge to harness large-scale impulse energy in short time is solved by the proposed unique energy conversion mechanism of the mechanical motion rectifier (MMR). Analogous to an electrical voltage rectifier, the MMR can directly convert irregular impulse into unidirectional rotation of the generator and maintain the high-speed rotation by disconnecting with the low-speed driving. With this motion mechanism, more energy from both downward and upward impulses can be harvested, which can produce three to four times more electricity than the conventional harvester without MMR mechanism. A prototype is tested using a passenger car. Up to 1270-W peak electrical power can be harvested from an electromagnetic generator when one-wheel axle of vehicle passes through the SBH at low speed. Moreover, in order to reveal the energy conversion mechanism of MMR and the interaction between the vehicle and SBH, a dynamic mechanical-electrical model of the MMR and a four-degree-of-freedom two-axle vehicle are established. Experimental measurement and numerical analysis demonstrate the effectiveness of the energy conversion mechanism of the MMR. Vehicle dynamics assessments under the impulse excitation show that the harvester can reduce the shock transmitted to the vehicle and improve vehicle comfort as well. The capability in generating the large-scale electrical power by the proposed SBH demonstrates the potential to power road-side electrical devices for smart transportation network.