Yao Xingjia

Individual pitch control for variable speed turbine blade load mitigation

Dynamic load is a key consideration in large scale wind turbine design. It is approved that the performance of controller can distinguish impact wind turbine loads. During pitch control algorithm design, if load influence is considered, it will be benefit to lower cost of whole wind turbine and extend longevity. In this paper, an individual pitch controller is developed based on a kind of model free control strategy, to mitigate the blade root load for variable speed wind turbine. The measured blade root bending moment is taken as one of the inputs of the controller, and the three pitch demand as the controller output. The control strategy was simulated in bladed external controller based on a 3.0 MW doubly fed variable speed wind turbine model, the simulation result verified itpsilas feasible and effective. The blades root load is mitigated evidently compared to classic collective pitch control.

Integration of large doubly-fed wind power generator system into grid

This paper models the doubly-fed variable speed constant frequency (VSCF) wind power transmission system, including the wind variation, wind wheel dynamic, mechanical swing, drive train, generator dynamic, power system etc. Based on the FD61-1000 prototype doubly-fed generator wind power system design parameters, by using MATLAB Simulink tools to simulate the whole system, this paper finally reveals the doubly-fed VSCF wind turbines operation characteristic in power system and influence to other load under condition of wind variation

Decoupling control of Doubly-Fed Induction Generator based on Fuzzy-PI controller

In this paper, first a theoretical analysis for wind turbine and Double-Fed Induction Generator (DFIG) is processed, given the mathematical models of them. Aiming at the problems of the conventional PI controller, a Fuzzy-PI control strategy is presented. A comparison between the developed vector controller with the proposed Fuzzy-PI strategy and the same vector controller with a conventional PI strategy employing fixed gains has been done. The simulation results also show that using the proposed controller, the dynamic response of the system can be improved and more precise control is achieved.

Dynamic Characteristic of the Drive Train of DFIG Wind Turbines during Grid Faults

During a grid voltage drop ,a problem is resonances in the drive-train shaft between the wind turbine and induction generator. Disadvantageous effects caused by this are noticeable vibrations and high mechanical stresses due to torque oscillations. The oscillations can be damped using The Drive Train Damper, which is used to mitigate fatigue loading of drive train components, controller consisting of a nonlinear observer to estimate the torque in the rotor and computes a damping torque signal that is added to the driver’s demand. The control algorithm was implemented in the existing motor control unit without any additional hardware cost. The controller was successfully tested in a test. The resonances can essentially be eliminated.

Coordinate control strategy based on expert decision system of wind turbine

In this thesis, the torque control, pitch control and general wind turbine coordinate control strategy of variable-speed adjustable-pitch wind turbine were researched. The control object is local SUT-1500 wind turbine based on independent design. First, the control object was modeled by the modal linearization process using Bladed software, among which the mechanical dynamic response was considered. Then the operation range of wind turbine was divided into several regions and the main control strategy of each region was researched. After the description of optimal tip speed ratio control in region 2, the PID control and Simplex Method PID parameters optimal were used in region 2psila torque control and region 3psila pitch control. In the end, the coordinate control strategy based on Expert Decision System of the general whole wind turbine was described and comparatively analyzed based on experiment results.

Research and simulation of direct drive wind turbine VSCF characteristic

For the purpose of achieving VSCF control system, this paper, stemming from the aerodynamics basic theory, analyzing the principle of pursuiting most wind energy. Through constructing the wind turbine stress model. Theory Wind energy utilization modulus is inferred in this paper. The paper focuses on VSCF control theory and operation mode. Firstly, the analysis of the relationship diagram of power curve in different wind speed is represented. Secondly, an optimal power curve is found. The wind turbine which works along this curve could obtain a maximum output power, achieving the goal of VSCF.

Analysis of 1MW Variable Speed Wind Turbine Parameter Optimal Design Based on Cost Modeling Method

During the industrialization process of large scale variable speed pitch regulated wind turbine prototype, the problems of how to decrease cost of energy and improve economical index, and how to conduct parameters optimal design were discussed. First, the calculation flowchart of cost of energy (COE) and basic principle of cost modeling method were described. Second, taking the national 863 project Mage-watt variable speed Constant frequency Wind turbine research fruit SUT-1000 wind turbine prototype for example, parameters optimal design and comparison of rotor diameter and rated wind speed for each other, sensitivity analysis of changing factor determined by experience were described. Finally, under the equivalent capacity restrict condition, the parameters synthesis optimal design was described, suit for different wind farm site.

Research of Doubly Fed Variable Speed Wind Turbine Power Output Performance

The model of the whole doubly fed variable speed regulated pitch wind generation system was founded to do power output performance simulation. The method of sensorless direct torque control (DTC) and model referencing adaptive system (MRAS) method were used in power regulation control. The results of simulation on variable speed power control performance based on 1.5MW SUT-1500 wind turbine prototype were shown out. The experiment of synchronization and get connected to the grid were given out, and some analysis compared with synchronous generation wind system were carried out.

DTC in Doubly-fed VSCF wind turbine control system

To solve the connection to the grid and power control problems of doubly-fed variable speed constant frequency (VSCF) wind turbine control system , the method of rotor magnetic flux direct torque control (DTC) was used to regulate rotor side AC exciting ,and get the aim of controlling stator side output. The control principle was described, the trial control scheme was established, and the performance was verified by a 30 KW wind turbine trial platform .The trial results of control strategy were obtained on the process of synchronization and fore-and-aft getting connected to the grid. By testing and analyzing, the validity of the control method is confirmed ,which can be popularized to other similar generator system.

Pitch-regulated Mechanism of the Neural Network Control based on Hebbina Supervised Learning Algorithm

Pitch-regulated mechanism servo of wind turbine system is a slow time-variable nonlinear system. According to the requirement of the 1 MW wind turbine with variable speed and constant frequency, the parameters of its PID controller need to be learned or adjusted at real time. Therefore, we design this neural net PID controller based on the Hebbina supervised learning algorithm to realize the self-study and self-regulating of the wind turbine pitch control with hydraulic system. According to the practical data collected from the operation of 1 MW wind turbine, the learning speed (etai) of Hebbina supervised learning algorithm can be fixed off-line so that the wind turbine can operate under good conditions. The paper gives the simulation results with comparison and the application of control strategy on the 1 MW wind turbine system.