Geometry optimization of a MEMS-based energy harvesting device

A MEMS based energy harvesting device is designed to convert mechanical vibration energy to electrical energy via piezoelectric effect. In order to improve the performances of the device, the geometry has been optimized by using moving mesh ALE model available in Comsol Multiphysics. The thickness, length and width of metal and ZnO are varied to get maximum displacement and voltage. The length, width and thickness of cantilever are obtained as 2000μm × 120μm × 5.4μm. In order to lower resonance frequency and maximize the output voltage, a proof mass is placed on tip of cantilever. The dimensions of proof mass are 237μm × 120μm × 237μm and mass is 0.145mg. Cantilever beam resonated at a frequency of 630Hz with acceleration of 1g and an output voltage obtained for d₃₁ is 1.06V and for d₃₃ is 3.85V . The proposed device is suitable for vibration energy harvesting and can be used as potential micro-generator.