SBIR Phase I: Prototype and Manufacture of Small-scale Axial Permanent Magnet Generator

The broader impact/commercial potential of this project is to address the deficit in portable power across sectors due to a lag in innovations in battery technology. Access to portable power is a universal problem. Wearable energy harvesting devices offer part of the power solution - human motion provides enough energy over a day such that ?wasted? energy can be captured and converted to enough usable electrical energy to power a variety of portable electronics. Wearable harvesters, such as a foot charger worn in a shoe, can seamlessly integrate into a user?s natural motion without causing the user any fatigue. Therefore, wearable energy harvesting technology is applicable to a wide variety of applications, including developing regions, military/aid organizations, consumer electronics and outdoor gear. Devices that implement mechanical systems have high theoretical power to weight ratios and produce enough power to charge small mobile electronics. To improve these devices, additional optimization on the limiting feature - the PMG - is necessary. This Small Business Innovation Research (SBIR) Phase I project will reduce the size and increase the efficiency of axial permanent magnet generators (PMGs) for energy harvesting applications. There are two types of PMGs used in current mechanical harvesting applications: radial and axial generators. Both produce multi-phase AC power, can be optimized for geometry and weight, and are used extensively in wind turbines on a large scale. Radials, because of their relative ease of manufacture, are designed for small-scale energy generation applications, most popularly in hand-crank generation devices. However, wearable energy harvesting applications have very strict volume requirements. The small, flat profile required for volume optimization suggests that axial PMGs are more space efficient for wearables. Essentially, to achieve a flatter profile in which height of the overall mechanism is minimized at the expense of increasing diameter, an axial generator would produce more power. The objectives of this project are to validate axial PMG simulations with physical prototypes, prove axial PMGs create a power increase of at least 10% over radial PMGs in existing commercial systems, and to evaluate the feasibility of manufacturing axial implementations at scale.