Dynamic Modeling of Wind Turbines Based on Estimated Wind Speed under Turbulent Conditions

Abstract

Large-scale wind turbines with a large blade radius rotates under fluctuating conditions depending on the blade position. The wind speed is maximum in the highest point when the blade in the upward position and minimum in the lowest point when the blade in the downward position. The spatial distribution of wind speed, which is known as the wind shear, leads to periodic fluctuations in the turbine rotor, which causes fluctuations in the generator output voltage and power. In addition, the turbine torque is affected by other factors such as tower shadow and turbine inertia. The space between the blade and tower, the tower diameter, and the blade diameter are very critical design factors that should be considered to reduce the output power fluctuations of a wind turbine generator. To model realistic characteristics while considering the critical factors of a wind turbine system, a wind turbine model is implemented using a squirrel-cage induction motor. Since the wind speed is the most important factor in modeling the aerodynamics of wind turbine, an accurate measurement or estimation is essential to have a valid model. This paper estimates the average wind speed, instead of measuring, from the generator power and rotating speed and models the turbine’s aerodynamics, including tower shadow and wind shear components, without having to measure the wind speed at any height. The proposed algorithm overcomes the errors of measuring wind speed in single or multiple locations by estimating the wind speed with estimation error less than 2%.

Optimum Resilient Operation and Control DC Microgrid Based Electric Vehicles Charging Station Powered by Renewable Energy Sources

“…The charging point in the station provides four typical DC chargers and two fast DC chargers (the fast charger typically requires 20 min to complete charging 80%, while the standard charger requires about 11 h to complete 80% charging). For example, the Nissan leaf car has about 24 kWh lithium-ion battery banks to store and supply power for EV motor [37][38][39][40]. Hence, within 30 min it reaches about 80% of its capacity at level 3 charging condition.…”

“…On the other hand, the resulting signal from the MPPT controller is regulated using a PI controller. Then the output of the internal loop is compared with the reference current produced by the outer loop to generate the PWM signal [38][39][40].…”

Design of State Feedback Current Controller for Fast Synchronization of DFIG in Wind Power Generation Systems

“…where P e is the generator electrical power, J is the system moment of inertia, B t is the friction coefficient, and ω m is the blade rotational speed. By substituting the maximum power from (13) into (14), the DFIG maximum generated power P e, max at each time step can be calculated as follows [34]:…”

“…Total harmonic distortion should be minimized. The current controller techniques listed in the literature can be divided into two main categories [14][15][16]: linear and nonlinear controllers. Proportional-integral (PI) stationary and synchronous, state feedback, and deadbeat controllers are examples of linear control techniques.…”

Real-Time Reliability Monitoring of DC-Link Capacitors in Back-to-Back Converters

“…The first step is to obtain both w and b to minimize the Energies 2019, 12, 2369 5 of 11 real data differences outside the insensitive region, which are determined by slack variables ξ and ξ * . To minimize the empirical risk, the slack variables are applied as [25] R reg ( f ) =…”