Environmental Engineering Reference
In-Depth Information
Chapter 2
High-Order Sliding Mode Control
of DFIG-Based Wind Turbines
Mohamed Benbouzid
Abstract Actually, variable speed wind turbines are continuously increasing their
market share, since it is possible to track the changes in wind speed by adapting
shaft speed, and thus maintaining optimal power generation. The more variable
speed wind turbines are investigated, the more it becomes obvious that their
behavior is significantly affected by the used control strategy. Typically, they use
aerodynamic controls in combination with power electronics to regulate torque,
speed, and power. The aerodynamic control systems, usually variable-pitch blades
or trailing-edge devices, are expensive and complex, especially for larger turbines.
This situation provides a motivation to consider alternative control approaches.
This chapter deals, therefore, with high-order sliding mode control of doubly-fed
induction generator-based wind turbines. This kind of control strategy presents
attractive features such as chattering-free behavior (no extra mechanical stress),
finite reaching time, and robustness with respect to external disturbances (grid
faults) and unmodeled dynamics (generator and turbine). High-sliding mode
control appropriateness will be highlighted in terms of sensorless control and
enhanced fault-ride through capabilities. Simulations using the NREL FAST code
will be shown for validation purposes.
Keywords Wind turbine
Doubly-fed induction generator
High-order sliding
modes
High-gain observer
Control
Sensorless control
Nomenclature
WT
Wind turbine
DFIG
Doubly-fed induction generator
HOSM
High-order sliding mode
MPPT
Maximum power point tracking
FRT
Fault ride-through
