Hybrid electromagnetic shock absorber for energy harvesting in a vehicle suspension

Electromagnetic harvesters need to be designed with a mechanism to amplify the coil relative velocity to ensure compact size and lower weight. This paper discusses a novel technique to use fluid link for velocity amplification in an electromagnetic shock absorber. Incorporation of the fluid amplification significantly improves harvested power, without affecting the system dynamics. Numerical modelling and experimentation of a prototype shock absorber comprising of high energy rare earth magnets have been presented. Peak coil voltage of 0.60-24.2 V was recorded during experimentation on the prototype. Experimental and simulation results validate that incorporation of the fluid amplification link improves the harvested electric power by 9702%. Comprehensive design procedure for better harvesting efficiency and vibration isolation has been discussed. Lastly incorporation of the shock absorber in McPherson strut suspension is illustrated. The real size version will be able to harvest peak power of 18-227 W for the suspension velocities of 0.15-0.4m/s.