Coupled dynamic FE analysis of permanent-magnet mechanical vibration energy harvesting converter

The paper presents a coupled dynamic mechanical-electromagnetic finite element analysis of a vibration energy harvesting converter with permanent-magnet excitation. The system consists of a small, miliwatt power range, linear-motion permanent-magnet generator connected to a cantilever-beam spring element. The finite element equations derived for the mechanical part of the system according to the 1-D Timoshenko beam theory are coupled strongly with equations describing the 2-D distribution of magnetic field in the generator and those associated with the electric circuit. The time-stepping procedure based on the Crank-Nicolson discretisation schema is applied to the obtained system of differential-algebraic equations. The model is shown to provide satisfactory predictions of the system dynamic performance which is confirmed experimentally.