Hamed Habibi

Optimum efficiency control of a wind turbine with unknown desired trajectory and actuator faults

The operational wind turbine efficiency in the power maximization regions and reliability improvement to reduce the produced power cost can both be enhanced by using an appropriate controller to cope with the highly nonlinear behavior of wind turbines in the presence of wind speed variation and actuator faults. In this regard, a nonlinear controller is proposed to make the wind turbine operate effectively despite some of the actuator faults, similar to the fault-free case. The considered actuator faults are pitch and generator actuator biases, as well as pitch actuator dynamic change, including pump wear, hydraulic leak, and high air content in the oil. Also, the wind speed is assumed to be an unmeasurable disturbance, and, accordingly, when using the neural network scheme, the unknown desired trajectory is reconstructed, so that the captured power is maximized. The proposed controller is shown to be able to keep the wind turbine tracking the reconstructed desired trajectory with sufficient accuracy. By u...

Sensor fault detection and isolation: a game theoretic approach

ABSTRACT This paper studies sensor fault detection using a game theoretic approach. Sensor fault detection is considered as change point analysis in the coefficients of a regression model. A new method for detecting faults, referred to as two-way fault detection, is introduced which defines a game between two players, i.e. the fault detectors. In this new strategic environment, assuming that the independent states of the regression model are known, the test statistics are derived and their finite sample distributions under the null hypothesis of no change are derived. These test statistics are useful for testing the fault existence, as well as, the pure and mixed Nash equilibriums are derived for at-most-one-change and epidemic change models. A differential game is also proposed and solved using the Pontryagin maximum principle. This solution is useful for studying the fault detection problem in unknown state cases. Kalman filter and linear matrix inequality methods are used in finding the Nash equilibrium for the case of unknown states. Illustrative examples are presented to show the existence of the Nash equilibriums. Also, the proposed fault detection scheme is numerically evaluated via its application on a practical system and its performance is compared with the cumulative sum method.