Experimental and Numerical Investigation of Energy Harvester Based on Magnetic Rolling Pendulum

In the paper, an innovative system for energy harvesting is presented, based on a magnetic pendulum. The proposed system is characterized by nonlinear behaviour that depends on the initial conditions of vibration. The appearance of nonlinearities can provide a broadened bandwidth at resonance zones for energy harvesting. Usually the second resonance manifests a low output harvested electric energy in mechanical systems compared to a main resonance zone. In this work, the system is proposed, which provides high output parameters for energy harvesting in both primary and secondary resonance zones. The magnetic pendulum focuses on converting mechanical energy into electrical energy by utilizing a subsystem based on coils. The main concept of this solution involves the use of a permanent rolling magnet between two magnetic bumpers. The system provides behaviour corresponding to double solutions by sweeping up and sweeping down the excitation frequency within the first and the second resonances, and it is associated with initial conditions such as the angle of deflection and initial force of excitations. Introducing a variable distance between the bumpers of magnets, the energy harvesting efficiency is modified. Applying such a magnetic pendulum system with variable mechanical input parameters opens perspectives for effective energy harvesting in a way that can be adapted to variable environmental conditions.