Principal Engineering /Mechanical Design and Analysis /Boulder Wind Power

It’s difficult to see how wind turbines can progress beyond conventional designs unless weight comes out of nacelles and reliability improves. A permanent-magnet generator that allows dispensing with a gearbox seems an alternative, but it comes with a high-weight handicap. Cisco Oyague, Principal Engineer, Mechanical Design and Analysis with Boulder Wind Power (BWP) has a few ideas for minimizing weight.

His idea is to apply a tensioned spoke to the generator for a relatively rigid structure in torsion so it transmits torque where needed, but is relatively soft or flexible axially and angularly. In the end, it should be a light weight, PM generator.

Before coming to BWP, Oyague spent eight years designing and analyzing dynamic systems in the wind industry. His experience includes serving as the lead analyst for the National Renewable Energy Laboratory’s Gearbox Reliability Collaborative, as well as developing and validating wind-energy models. He holds a B.S. in mechanical engineering from University of Denver and a master’s in computational mechanics of materials and structures from Stuttgart Universität.

Since joining Boulder Wind Power in mid-2010, Oyague has led the mechanical design of BWP’s full-scale generator test stand, linear and nonlinear progressive structural analysis, along with the design and analysis for all bolted connections in the full-scale 3.0-MW generator. He has also led the design and analysis for all stator and rotor support structures in BWP’s first commercial prototype generator.

The design also selectively introduces flexibility into the generator support structure and locally manages the air gap between rotor and stator with a patented air-gap control system. This significantly reduces the mass and cost of the BWP generator support structure, as compared to conventional approaches that rely on heavy structures for stiffness in all dimensions.

The effort has paid off. Oyague was issued his first U.S. patent in 2012 for the tensioned-spoke concept as the support structure in the company’s large diameter, multi-megawatt, direct-drive generator. The patent, “Structure for an electromagnetic machine having compression and tension members,” provides a lightweight and cost-effective support structure for large diameter electric machines.