J. Shen

This paper presents a linear generator used for energy harvesting system equipped in footwear, which scavenges power from back-and-forth motion during walk. Structure of the electric machine is studied, and sizing optimization by finite element analysis (FEA) is detailed. A prototype has been built, validating that the simulated and test results have a good agreement.

This paper presents a comprehensive analysis and comparison of air-cored axial flux permanent magnet (AFPM) machines with different types of coil configurations. Although coil factor is particularly more sensitive to coil band width and coil pitch in air-cored machines than conventional slotted machines, remarkably no comprehensive analytical equations exist. Here new formulae are derived to compare the coil factor of two common concentrated-coil stator winding types. Then respective coil factors for the winding types are used to
determine the torque characteristics, and from that the optimized coil configurations. Three -dimensional (3D) FEA
models are built to verify the analytical models. Furthermore,
overlapping and wave windings are investigated and compared
with the concentrated-coil types. Finally, a prototype machine is designed and built for experimental validations. The results
show that the concentrated-coil type with constant coil-pitch is
superior to all other coil types under study.