Polinder, Henk8; Ferreira, Jan Abraham8; Jensen, Bogi Bech1; Abrahamsen, Asger Bech3; Atallah, Kais9; McMahon, Richard A.10
1 Department of Electrical Engineering, Technical University of Denmark2 Center for Electric Power and Energy, Department of Electrical Engineering, Technical University of Denmark3 Department of Wind Energy, Technical University of Denmark4 Wind Energy Systems, Department of Wind Energy, Technical University of Denmark5 Delft University of Technology6 University of Sheffield7 University of Cambridge8 Delft University of Technology9 University of Sheffield10 University of Cambridge
This paper reviews the trends in wind turbine generator systems. After discussing some important requirements and basic relations, it describes the currently used systems: the constant speed system with squirrel-cage induction generator, and the three variable speed systems with doubly fed induction generator (DFIG), with gearbox and fully rated converter, and direct drive (DD). Then, possible future generator systems are reviewed. Hydraulic transmissions are significantly lighter than gearboxes and enable continuously variable transmission, but their efficiency is lower. A brushless DFIG is a medium speed generator without brushes and with improved low-voltage ride-through characteristics compared with the DFIG. Magnetic pseudo DDs are smaller and lighter than DD generators, but need a sufficiently low and stable magnet price to be successful. In addition, superconducting generators can be smaller and lighter than normal DD generators, but both cost and reliability need experimental demonstration. In power electronics, there is a trend toward reliable modular multilevel topologies.
I E E E Journal of Emerging and Selected Topics in Power Electronics, 2013, Vol 1, Issue 3, p. 174-185