Recovery Act - High Torque, Low Cost, Direct-Drive Rotary Generator

Columbia Power has identified a highly effective wave energy converter that efficiently converts wave motion into rotary motion for conversion to electric power. Prior research by Columbia Power has identified that a power take off (PTO) utilizing rotary direct drive electric generation will provide a cost advantage over other PTO alternatives. The specifications for this direct drive rotary generator are not satisfied by any existing commercial product, thus a research, design, and demonstration effort is required in order to minimize the commercial risks of developing such a machine. The required direct drive rotary PTO specifications include high torque, high efficiency, a low friction marine bearing/seal solution, long life in a marine environment, high bearing loads, and a cost effective design. How Problem is addressed: Phase I of the research will include electromagnetic modeling, and design investigations of a permanent magnet rotary generator design which incorporates high efficiency, high torque, and a small air gap design that prioritizes low material and manufacturing costs. Several design concepts are proposed and will be investigated; the most promising will be designed for scaled prototype build and analysis. The generator design will include practical material and manufacturability limitations imposed by our composites manufacturing partner (Ershigs Inc.) and essential electromagnetic design priorities imposed by constrain costs. Phase II of the research will include a scaled build and testing including a detailed cost analysis of a full scale design. Phase 2 would complete with a full scale design of a demonstration device. Following full scale test and validation of the generator, this technology will be deployed in the Columbia Power wave energy buoy. Commercial Applications and Other Benefits: Low speed and high torque is a common characteristic for the prime mover of renewable energy sources such as wind, tidal, and wave energy. These systems will benefit from a cost effective rotary generator solution. If the electromagnetic and interface design concepts proposed in this project can be implemented in a cost effective way, significant cost reductions will be realized for these renewable energy systems.