| Abstract |
This paper gives an overview of electrical conversion systems for wind turbines. First, the basics of wind energy conversion with wind turbines are reviewed and
requirements with respect to the electric system are considered.
Next, the three classical conversion systems are described with
their strengths and weaknesses: constant speed, variable speed
with doubly-fed induction generator and variable speed with direct-drive generator. The applied electric converters are shortly addressed. Finally, alternative generator systems and trends are discussed. There is a clear trend towards variable speed systems. Doubly-fed induction generator systems are
increasingly equipped with grid fault ride through capabilities.
For direct-drive turbines, the radial flux permanent-magnet synchronous generator is cheaper and more efficient than the
electrically excited synchronous generator. It is expected that
the voltage level of generators will increase up to values in the
order of 5 kV. |
