Improving energy harvesting by internal resonance in a spring-pendulum system

This paper proposes a two-to-one internal resonance to widen the bandwidth of vibratory energy harvesters. To describe the improved characteristic, an electromagnetic spring-pendulum harvester is designed. Approximate analytical solutions of the electromechanical coupled system are carried out by introducing the method of multiple scales, and the frequency response relationships of the displacement and the current are obtained. The character of broadband harvesting performance is examined, the two peaks and double jump phenomena for variation of design parameters were observed. The effect of key control parameters on the harvesters bandwidth is considered, and the nonlinear behaviors of the harvester are validated via numerical results.