Modeling, design and optimization of hybrid electromagnetic and piezoelectric MEMS energy scavengers

A hybrid energy scavenging technique is introduced to harness ambient energy through electromagnetic and piezoelectric mechanisms to achieve higher power density and higher energy conversion efficiency in a high mechanical damping MEMS structure. By inspecting the second-order mechanical dynamic system for electromagnetic and piezoelectric energy conversions, a unified model is proposed to capture the relation of the recoverable hybrid energy and the input vibration frequency as well as the amplitude. Design trade-offs are considered for the hybrid scavenger size and power maximization. A hybrid MEMS energy scavenger design with optimization results for implementation is shown as an example.