For the electret-based vibration energy harvester (eVEH), most of the theoretical studies focus on its electrical model, while the dynamic model is usually lumped as a mass-spring oscillator. This method might be inaccurate for the cantilever type eVEH, as the deformation of the counter electrode is not negligible. In this work, we endeavour to propose a dynamic model of the cantilever type eVEH. The electromechanical governing equations are derived from the Hamilton's principle and discretised using finite element method. In order to make it more computationally efficient, this model is further reduced by modal method. This work provides an accurate and efficient computational model and provide some useful guideline in the de-sign and optimization of the cantilever type eVEH.
