Novel Medium Speed Wind Turbine Generator

Wind turbines provide an environmentally clean way of generating energy in ever more cost effective ways. Sites that that are classified as ‘high class’ generate power at lower costs than other generation alternatives. Unfortunately, the number of these sites is limited and lower costs and/or higher outputs are needed for future sites to be cost effective. This is particularly true with the phased removal of the Production Tax Credit (PTC). LC Drives is proposing a way to significantly reduce the cost of wind power that will allow more sites to be cost effective, allowing significant growth in the amount of wind power generated. LC Drives will develop a medium-speed generator for utility scale wind that is less than half the size of the best medium-speed generators on the market today. This smaller generator will allow system advantages that will produce more power and will also cost less to produce. This change will significantly reduce the Levelized Cost of Energy (LCOE) of wind, helping to meet the DOE’s goal for wind power cost to be reduced. The smaller generator concept is based on patented and ongoing development efforts for technology that LC Drives has developed for marine propulsion applications. This technological breakthrough cools the motor windings more effectively thereby allowing both higher slot current density and increased torque in a given volume. The outcome of this approach is the ability to develop much smaller machines when compared to what would be state of the art liquid cooled machines currently available.The existing range of machines is 20 inches in diameter with powers configurable to over 2MW at 1500 rpm achieved by increasing stack length. Medium-speed wind generators require 3-10MW capacity at speeds in the range of 300-600 rpm. To achieve this increase in output requires scaling the 20- inch machine to 72 inches in diameter whilst maintaining a design that is scalable in stack length. Traditional thought processes state that medium-speed drivetrains are only advantageous for larger offshore wind applications, but the smaller generator technology proposed here allows lower cost wind systems down to 3 MW and therefore applicable to almost all onshore applications. For larger offshore applications the LCOE reduction is also significant. This generator approach will reduce the LCOE of wind by 3% due to increase in energy produced, lower production costs, and reduce maintenance. Lowering utility scale wind LCOE is clearly defined in topic 14b, Innovations in Utility-Scale Performance, but does not ask for drivetrain improvements because it is assumed that the savings would be minimal. The ability to make such a dramatic improvement in the weight of the generator opens up the opportunity to accomplish the 3% reduction. In this industry, even fractional % reductions in LCOE are considered significant with rare credible opportunities for savings over 1%.The proposed program will complete the detailed design of the 72 inch diameter machine and quantify the benefit for wind LCOE. A phase II program will build a MW scale prototype that will be able to be dynamometer tested in LC Drives world class facilities. LC Drives has a support letter from ABB that is the largest motor/generator manufacturer in the world.