Optimization of an Electromagnetic Energy Harvesting Backpack Under Actual Walking and Running Scenarios

Energy harvesting technology can provide a renewable, portable power source for soldiers who rely solely on battery power in the field. Electromagnetic energy harvesters scavenge energy from wasted kinematic and vibration energy in human motion. The motion of interest in this paper is vertical hip displacement during human gait that acts as a base excitation. The placement of a permanent magnet based linear generator mounted in a backpack can make use of this excitation that results in relative motion of the magnet to the coil of copper wire, which induces an electric current. This current can be used to charge a battery or capacitor bank installed on the backpack to power portable electronic devices, thereby reducing the need for extra batteries and overall battery weight. The purpose of this research is to use a multi-variable optimization algorithm to identify an optimal coil and magnet layout for power maximization. Results from this study will pave the way for a more efficient energy harvesting backpack while providing better insight into the efficiency of magnet and coil layout for various applications for electromagnetic power generation from vibration.