Innovative In-Plane Converter Design for a Capacitive Energy Harvester

This work presents an innovative design of a MEMS vibration energy harvester based on electrostatic transducer and allowing multidirectional in plane excitation. The proposed design uses a single variable capacitor axially attached to a shallow arched microbeam. The latter generates axial displacements when it is subject to external excitation. It is expected that the fundamental resonance frequency of the microbeam can be triggered by imposing a secondary DC voltage. The equations of motion are derived using the Hamilton’s principle for large displacements of the microbeam by taking into account the nonlinear form of the electrostatic force. Numerical simulations of the axial and transverse displacements of the microbeam are extracted and coupled to a conditioning circuit. The generated numerical simulations are used to calculate the harvested energy for several directions of the excitation. It was shown that, in contrast to the parallel-plates beam-based designs, the suggested design can generate energy even if the direction of excitation is changed, as a result the energy is augmented if the excitation is present in two, or even more, different in-plane directions.