Optimal power utilisation with doubly-fed full-controlled induction generator

Doubly-fed induction generators are mainly used for wind energy conversion in MW power plants. They are controlled by a rotor inverter and DC-linked front-end converter while the stator is linked directly to the grid. If a DC-bus bar is available, a double feeding can occur about the inverter. This paper describes a doubly-fed full-controlled induction wind generator which offers a higher flexibility of stator side control to ensure minimal losses as well as optimal power utilisation. The special wind converter system has been investigated at a glance of installed off-shore MW-generators, where a DC-transmission is advantageous because of the avoided reactive power.