Development of a Concentrated Winding PM Alternator for a Small Wind Turbine

Small wind turbines in the 5 – 25 kW range for rural residences, farms and small businesses have a large market potential due to the millions of suitable sites in the U.S. and overseas. But industry sales have declined in recent years as the costs of photovoltaics have dropped and state incentive programs have reduced. This is unfortunate because most of the equipment for solar power is imported, while most small wind turbines installed in America are built in America. Small wind could contribute to a renaissance in U.S. manufacturing if sales increased significantly, and that would require a significant drop in costs. A next-generation small wind turbine rated at 15 kW has been developed utilizing new airfoil, rotor blade, blade manufacturing and stall control technology. The result is that a larger and more efficient rotor can double energy production without requiring a larger nacelle and tower. This new turbine, when released in late 2017, will drop the Levelized Cost of Energy (LCOE) by 50% compared to the current best-selling turbines in its size range. The costs could be further improved, however, with a lower cost direct-drive permanent magnet alternator design to replace the current 10-year old technology. The alternator is important because it accounts for over 50% of the direct manufacturing cost of the wind turbine itself. New permanent magnet motor/generator architectures with lower costs and higher performance have been developed for use in hybrid electric vehicles. One family of EV motor/generator architectures, Concentrated Windings, will be evaluated and applied to the design of an advanced direct-drive permanent magnet alternator for a 15 kW small wind turbine. This is projected to produce a 30% reduction in costs and a 100% improvement in peak torque. Phase I activities will be use magnetic analysis software to design and evaluate the characteristics for alternative designs suitable for the 15 kW turbine and then compare manufacturing costs relative to the existing baseline. Then Choose a design and prepare a detailed alternator design for the 15 kW turbine. And Build and test a prototype alternator and compare it against the existing product. The objective for Phase I is to design and validate an advanced small wind alternator that can be moved directly into beta tests and substituted for the existing design in the production 15 kW. This will allow a price reduction of 20-30% for the turbine itself or ~ 6% of the overall turbine system installed cost. Under “zero-down” leasing programs the projected sales in the 2018-2019 time frame are 800 systems, or 12 MW, and an annual growth rate of 20%.