Innovative wind power drivetrains with improved components
Keeping low operation and maintenance costs and increasing reliability of wind turbines are high priorities if Europe is to reach 20 % renewable energy in the overall energy supply by 2020. Brushless generator technology can help increase wind turbine installations while also retaining Europe's competitiveness. The WINDRIVE (Industrialization of a 3 MW medium-speed brushless DFIG drivetrain for wind turbine applications) consortium developed brushless doubly-fed induction generator (DFIG) technology for wind power generation, taking it from the laboratory to an industrial-scale machine for multi-megawatt wind turbine applications. Medium-speed wind turbine drivetrains (WTDTs) are more reliable than current WTDTs, which are based on a three-stage gearbox and DFIG. Provided that the range of speeds is moderate, the converter rating needs only to be a fraction of the total generator output, thereby keeping the system cost low yet retaining reliability. The converter rating is generally about one third of the generator rating, allowing speed variations of about 33 %. Varying the converter voltage can be used to manage the reactive power flow from the generator. Control schemes were developed to enhance the response of the system to changing wind speeds and to accommodate varying grid conditions. The majority of wind turbine failures happen within the gearbox, leading to costly repairs and downtime. This novel drivetrain integrates more efficient and reliable components. Project partners developed a two-stage gearbox, excluding the third high-speed stage, which is the part of the gearbox with the highest failure rate. WINDRIVE supports the exploitation of a more reliable and cost-effective generator system for the wind power industry. This novel and disruptive drivetrain technology together with the improved gearbox should lead to wider adoption of wind power generation, especially offshore, thereby boosting the low-carbon economy and increasing energy security for the EU.
Keywords
Wind power, medium-speed drivetrains, brushless generators, wind turbines, brushless doubly-fed induction generator, gearbox
