Maximum Power Control of Wind Turbines with Practical Prescribed Time Stability Based on Wind Estimation

Designated‐time stabilizing strategy for a class of time‐varying nonlinear systems and its application to pendulum system

“…[25][26][27][28][29][30] Based on the findings in References 25 and 26, a series of elegant works concentrated on the prescribed-time stabilization have been achieved for a broad class of nonlinear systems. [31][32][33][34][35] Unfortunately, in References 25-28, the time-varying function which approaches to zero at the prescribed time is a part of the denominator of the actual controller, which yields a technique issue: the magnitude of the resultant control would tend to infinity inevitably at that time instant, also referred to the singularity problem. In other words, the control action is only defined/usable on a finite-time interval and the control mission will be terminated in finite-time horizon without depicting the system behavior after the prescribed time.…”

“…To further overcome such a potential drawback, a new idea called prescribed‐time state convergence (stability) as well as a time‐varying feedback design was recently proposed in Reference 25 where the upper bound estimate of the settling time equipped in fixed‐time convergence was revamped and advanced to be an arbitrarily tunable (i.e., “prescribed”) parameter irrespective of systems' initial states and/or other design parameters; this idea took an important step in accomplishing the fixed‐time stabilization with a desired upper bound estimate of the settling time and has received continuous attention recently 25–30 . Based on the findings in References 25 and 26, a series of elegant works concentrated on the prescribed‐time stabilization have been achieved for a broad class of nonlinear systems 31–35 . Unfortunately, in References 25–28, the time‐varying function which approaches to zero at the prescribed time is a part of the denominator of the actual controller, which yields a technique issue: the magnitude of the resultant control would tend to infinity inevitably at that time instant, also referred to the singularity problem.…”

Output Feedback Control for Spacecraft Attitude System with Practical Predefined-Time Stability Based on Anti-Windup Compensator

“…To deal with this problem, based on the concept of fixed-time sliding mode control, the problem of distributed output feedback attitude consensus control for multiple rigid spacecraft has been studied in [19], such that the requirement of an angular velocity measurement is removed, and the system trajectories converge to zero during a finite time that is independent of initial attitude. Although the upper bound of the settling time only depends on control parameters, it is difficult to determine a specific convergence time since at least four parameters contribute to estimating the settling time [20][21][22][23].…”

Maximum Power Tracking Control of Wind Turbines Based on a New Prescribed Performance Function

“…At this stage, the blade pitch angle is locked at the optimal value in order to optimize power production, and the torque control circuit is used to adjust the rotor speed to run relatively near to the ideal speed. Numerous control techniques, including tip speed ratio (TSR) control [3], optimal torque control [4], power signal feedback control [5], and extremum seeking control [6], etc., have been researched and used in this sector. However, their characteristics include a slow tracking speed and that tracking accuracy cannot be set in advance.…”

“…The contributions of this paper include: (1) The convergence rate and tracking precision can both be predetermined by the designer utilizing the new error transformation based on PPF; (2) Not only the tracking error variable, but also all other intermediate error variables will reach the predetermined stable region within a given time; (3) In spite of external disturbance, the WT can respond to the change of wind speed quickly and achieve maximum power control.…”