Xing Zuoxia

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.

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 on the optimization method of multi energy interconnected microgrid configuration and operation based on lifecycle cost

To solve the problem of the low return on investment in the traditional micro grid, multi energy interconnected micro grid were constituted by distributed photovoltaic, gas turbine, combined cooling heating and power supply system (CCHP). Because power generation of distributed photovoltaic has uncertainty and the load of cold, hot and electricity is unbalance, the optimizesion of microsource configuration and its operation must be made. The method of the genetic algorithms and linear programming is used to solve these. This optimize method was verified by MW-levels comprehensive community which the results show that the multi energy interconnected microgrid has economy and promotion value under the current price system and the condition of Comprehensive community.

The Study of the optimize Design for the Wind Turbines Controller

A nonlinear control method based on model linearization is established and a fuzzy controller is designed for the variable speed variable pitch wind turbines in this paper. The simulation results show that control performances have been improved, and the wind turbines controller is effective.