A novel hybrid energy harvester with increased power density

Abstract In this paper, a novel hybrid energy harvester is investigated by using a rotational generator and a surface permanent magnet linear generator (SPMLG). The rotational generator that was developed by Hendijanizzaded [1] can harvest maximum power under the optimum design process with constrain on the relative displacement of the mass. The aim of adding the SPMLG is to increase electrical damping that will affect the displacement of the moving mass. This idea is different than the existing hybrid systems in which energy is harvested from two different sources, such as sunlight and sound or heat and light to increase power extracted. The interactions between different electromechanical parameters can be taken advantages of to improve the power harvesting of the device. By adding SPMLGs to a rotational generator, electrical damping of the system will be increased while the mechanical parameters of the system, for example, the resonant frequency, the spring stiffness and the seismic mass are unchanged. The system model of the rotational and the hybrid harvesters will be established and numerically simulated. Also, the power extraction between the original rotational generator and the hybrid harvester under the same conditions will be compared to confirm the viability of the method. Obviously, the trade-off for this power increase is the additional weight of the SPMLGs that must be considered in the calculations of the power density which is outside the scope of this paper.