Design and optimization of a magnetically sprung block magnet vibration energy harvester

A magnetically sprung, electromagnetic vibration energy harvester with block magnets is presented. The harvester achieves one of the highest reported measured normalized power densities for a magnetic levitation energy harvester of 7000 mu W cm(-3) g(-2). The measured power output at 6.7 Hz was 410 mu W and 304 mu W at 0.1g and 0.075g acceleration amplitudes, respectively. The energy harvester was constructed using block magnets, which allow more flexibility in design compared to the typical cylindrical magnet devices. The device has been modeled using analytic equations to calculate the nonlinear magnetic forces and flux, which have been input into a time step model of the harvester to calculate power output. The full design procedure to optimize the device is presented. (C) 2014 Elsevier B.V. All rights reserved.