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The maximum power point tracking problem of variable-speed wind turbine systems is studied in this paper. The wind conversion systems contain both mechanical part and electromagnetic part, which means the systems have time scale property. The wind turbine systems are modeled using singular perturbation methodology. A linear parameter varying (LPV)...
Citations
... The output feedback H2|H∞ controller designing method has been suggested based on LMI for power system stabilizers. The robust power system stabilizers outperform the conventional power system stabilizers and have the damping ability for various kinds of generators [6]. Quasi-LMI formula can be utilized for designing uncertainty and wind turbines with turbulence. ...
... Thus, it is observed that all seven eigenvalues related to closed-loop system have a negative integer part indicating that the closed-loop system is stable. In figures (4-6) to (4)(5)(6)(7)(8), the zero input answer pertains to the system's outputs. It is observed that the controller has been able to stabilize all of the state variables of the system and regulate them on zero. ...
In this paper, the maximum power point tracking problem of variable-speed wind turbine systems is studied. Both mechanical part and electromagnetic part of the wind energy conversion system are taken into consideration. In view of the different time scales between the mechanical part and electromagnetic part, singular perturbation theory is applied to model the system in order to cope with the stiffness caused by the two-time-scale characteristic. Then, linear parameter varying (LPV) model is developed to approximate the nonlinear singularly perturbed model. In consideration of data detection time of the state variables, in practice, the control inputs are dependent on the states with a small time delay. Therefore, a novel delay dependent [Formula: see text] controller is designed to make the rotor speed track the reference rotor speed. Furthermore, it is proved that the closed-loop system under control is asymptotically robust stable using Lyapunov theory. In the end, an example simulation verifies the effectiveness and advantages of the developed method by means of comparison with optimal torque control.
Due to the intermittent nature of wind, the wind power output tends to be inconsistent, and hence maximum power point tracking (MPPT) is usually employed to optimize the power extracted from the wind resource at a wide range of wind speeds. This paper deals with the rotor speed control of a 2 MW direct-driven permanent magnet synchronous generator (PMSG) to achieve MPPT. The proportional-integral (PI), proportional-derivative (PD), and proportional-integral-derivative (PID) controllers have widely been employed in MPPT studies owing to their simple structure and simple design procedure. However, there are a number of shortcomings associated with these controllers; the trial-and-error design procedure used to determine the P, I, and D gains presents a possibility for poorly tuned controller gains, which reduces the accuracy and the dynamic performance of the entire control system. Moreover, these controllers’ linear nature, constricted operating range, and their sensitivity to changes in machine parameters make them ineffective when applied to nonlinear and uncertain systems. On the other hand, phase-lag compensators are associated with a design procedure that is well defined from fundamental principles as opposed to the aforementioned trial-and-error design procedure. This makes the latter controller type more accurate, although it is not well developed yet, and hence it is the focus of this paper. The simulation results demonstrated the effectiveness of the proposed MPPT controller.
