《Analysis，Modeling and Control of Doubly-Fed Induction Generators》 2005

jweisd

Analysis Modeling and Control of Doubly-Fed Induction Generators for Wind Turbines
Abstract
This thesis deals with the analysis, modeling, and control of the doubly-fed induction generator
(DFIG) for wind turbines. Different rotor current control methods are investigated with
the objective of eliminating the influence of the back electromotive force (EMF), which is
that of, in control terminology, a load disturbance, on the rotor current. It is found that the
method that utilizes both feed forward of the back EMF and so-called “active resistance”
manages best to suppress the influence of the back EMF on the rotor current, particularly
when voltage sags occur, of the investigated methods. This method also has the best stability
properties. In addition it is found that this method also has the best robustness to parameter
deviations.
The response of the DFIG wind turbine system to grid disturbances is simulated and verified
experimentally. A voltage sag to 80% (80% remaining voltage) is handled very well.
Moreover, a second-order model for prediction of the response of small voltage sags of the
DFIG wind turbines is derived, and its simulated performance is successfully verified experimentally.
The energy production of the DFIG wind turbine is investigated and compared to that of
other wind turbine systems. The result found is that the energy capture of the DFIG wind turbine
is almost the same as for an active stall-controlled fixed-speed (using two fixed speeds)
wind turbine. Compared to a full-power-converter wind turbine the DFIG wind turbine can
deliver a couple of percentage units more energy to the grid.
Voltage sag ride-through capabilities of some different variable-speed wind turbines has
been investigated. It has been found that the energy production cost of the investigated wind
turbines with voltage sag ride-through capabilities is between 1–3 percentage units higher
than that of the ordinary DFIG wind turbine without the ride-through capability.
Finally, a flicker reduction control law for stall-controlled wind turbines with induction
generators, using variable rotor resistance, is derived. The finding is that it is possible to
reduce the flicker contribution by utilizing the derived rotor resistance control law with 40–
80% depending on the operating condition.

gaojy1965

中文标题应为“双馈发电机分析、建模和控制”