Quantum mechanics

Adaptive control

Control (management)

Engineering

Fault detection and isolation

Biology

Statistics

Control engineering

Actuator

Computer science

Fault (geology)

Seismology

Controller (irrigation)

Geology

Physics

Nonlinear system

Sliding mode control

Mathematics

Agronomy

Artificial intelligence

Parametric statistics

Observer (physics)

Wind power

Control theory (sociology)

Lyapunov stability

Electrical engineering

Ocean Engineering

This paper addresses an Active Fault-tolerant Control (AFTC) based on Time Delay Control (TDC) and nonlinear disturbance observer for wind turbines, exposed to pitch system sensor and actuator faults, uncertainties and exogenous disturbances. The developed adaptive TDC uses Time Delay Estimation (TDE) to estimate parametric uncertainties and provides an appealing model-free structure. TDE is also applied as an online fault estimation algorithm. Then, an adaptive robust control is designed for TDC using a combination of adaptive sliding mode with novel adaptation laws and a nonlinear disturbance observer (NDO). Through estimating the exogenous disturbances, the control gain of discontinuous term of sliding mode control law is kept small which in turn results in reduced chattering. Thus, the proposed structure provides smooth control signals and can isolate and accommodate the effect of faults. Stability analysis is conducted based on Lyapunov Theory. To verify the validity of the proposed structure, the controller is implemented in FAST environment. Simulation results reveal the effectiveness of the proposed controller in the presence of different faults, as well as uncertainties and turbulent wind field, compared to two existing methods, gain schedule PI (GSPI) and nonlinear PI (N-PI) control schemes.

Pitch actuator fault-tolerant control of wind turbines based on time delay control and disturbance observer