Modeling and experimental study of a linear power generator for road energy harvesting

There are a large number of vehicles running on the road, and the shape of the road surface varies accordingly. Thus, this kinetic energy can be harvested to power electrical equipment along the road, and this energy harvesting technology has good environmental adaptability because it will not be affected by the sun, wind, or other natural environmental factors. A permanent magnet linear generator is designed and tested for road kinetic energy harvesting. The generator is described by a single degree of freedom system model with mass-spring-damping. The system response is analysed on the basis of the system model. The mover's vibration response is modeled over two stages according to the vehicle's wheel load. The power generation process is simulated and calculated according to the aforementioned models. The magnetic force and magnetic field are calculated by use of the finite element method; because of the non-linear magnetic force, the output electromotive force (EMF) is subject to frequency multiplication under conditions of sinusoidal displacement input. A prototype is manufactured and embedded in the road for experimental research purposes. The test result shows that the maximum peak-to-peak value of the output EMF and average power are up to 484.18 V and 255.1 W, respectively, as a car passes over the generator at a speed 20 km/h. Moreover, the time-domain and amplitude-frequency characteristics agree well with those calculated. It is demonstrated that the proposed model is able to describe the road power generator.