Xingjia Yao

Wind Turbine Control Strategy at Lower Wind Velocity Based on Neural Network PID Control

For the variable speed operation of large scale wind turbine, the vibrations become key problem that can not be ignored. In this paper, the active vibration control based on Neural Network PID control strategy was researched. Firstly, PID control algorithm was analyzed. Then, the PID control based on Neural Network was described especially BP Network and its algorithm. In the end, this control method was verified using simulation and prototype test. Keywords-Control; PID; Neural Network; Bladed I.INTRODUCTION The more complicated of controlled system, the higher of people requirements, further, people need control system could adapt to uncertainty, time-varying objects and environment ability. Traditional control method based on exact model can hardly meet the requirements. Control is defined as concept including decision, planning and learning ability. The neural network is paid more and more attention because of these advantages mentioned above. The control diagram of wind turbine is shown in Figure 1.

Pitch angle control of variable pitch wind turbines based on neural network PID

According with control theory of variable-speed and constant-frequency (VSCF) pitch-controlled wind turbine, neural network algorithm is adopted to predict pitch angle at real-time working condition, and to obtain more accurate pitch angle reference value. It enhances control precision of the entire pitch-controlled system.

The Dynamic Model of Doubly-fed Induction Generator Based on Wind Turbine

According to grid codes issued by utilities, tripping of wind turbines following grid faults is not allowed, and it is necessary to provide reactive power support to grid sometime. So this paper sets up a complete DFIG dynamic model, including the generator model, converter model and converter protection, grid model etc. to study the transient characters. The method of sensorless direct torque control (DTC) and model referencing adaptive system (MRAS) method were used in the converter control. At last, the results of simulation on DFIG transient power control performance based on 1.5 MW SUT-1500 wind turbine prototype indicated that the DTC control and the MRAC principle improve the system phase-ground fault ride-through capacity ,and fulfil the dynamic regulating of the DFIG external fault.

Characteristics of VSCF wind turbines under voltage disturbance

The wind turbines is often influenced by voltage disturbance because of voltage instability under the weakpower grids. This paper proposes a method for a variable speed constant frequency(VSCF) wind turbine with doubly-fed induction generator (DFIG) to stay connected to the grid during voltage disturbance. The keypoint of the method is to limit the inrush current in the rotor and the voltage in the DC bus in order to protect the wind turbines and the weak power grids. Then a detailed DFIG model is built and a control strategy is propsoed. In order to regulate network voltage, stabilize weak network, the DFIG using the proposed method can supply reactive power fast, hold system supply stability, reduce risk of voltage collapse and network splitting. Finally, the performance of the new control through severe voltage disturbance conditions is demonstrated by simulation.

Study on a New Control Strategy of Inverter of Outer Rotor Permanent Magnet Generator Wind Power System

For the consideration of the existing switching device power level, a converter circuit topology is proposed in this paper, which is accorded with the requirement of highpower direct-drive outer rotor permanent magnet generator. Particularly, a control method based on “non-controlled retification, boost chopper and SPWM inverter circuit” is proposed. Designs of the boost chopper circuit and the control system structure of SPWM inverter are mainly performed, then the block diagrams and control programs of the whole control system are set up. Finally Matlab/Simulink is used to carry on the simulation. The result of simulation showed that this method could meet the requirement of wind power generation system, and the feasibility and accuracy of the method are fully confirmed.

Dynamic model and simulation of doubly feed induction generator wind turbine

According to emergency grid rule requirements, wind farm should has the ability to stay connected and continue generation under external voltage failure conditions, that is, wind turbines have to keep in connection with grid and own continue power supply. Consequently, the dynamic model of double fed wind turbines, converter model and grid model were established to study the transent chatacters of DFIG. Also, current vector control method oriented by the stator flux was applied in converter control. Based on these, PSCAD was used in building models and simulating. Finally, the results shows that vector control is able to fulfill decoupled active and reactive power control of double fed generators and improve system low voltage ride through ability.

Study on power control of doubly fed wind turbine

This paper firstly introduces the system model of wind turbine. According to the input mechanical energy and the power curve of wind turbine, we study the Steady-state Characteristics, relationship of the power and turque. Then the power output characteristic of the wind turbine is simulated by MATLAB.The simulation result shows that the Double-Fed Induction Generator(DFIG) system can realize optimal power output-functions by adjust the power factor especially under the rated speed, then it can obtain maximum power output, this is a effective way to improve the efficiency of the wind turbine. This paper provide a reference of control strategy design of the wind turbine.

Based on mechanical and electrical decoupling of electric variable pitch control system

In this paper, a mechanical and electrical decoupling control system for the electric variable pitch control of wind turbine was discussed. First, considered the nonlinear mathematical model of the permanent magnet servo motor used electric variable pitch control of wind turbine, and through the identical change for above dynamic mathematical model, the electric variable pitch position servo control system with the electrical and mechanical decoupling was established. Then the experiment in time is beginning, and software is programmed with VC in Windows embedded control and in the servo system closed cycle no-load experiment, it has been carried out analysis on experiment result. So the results indicated that the mechanical and electrical decoupling control system of electric variable pitch respond quickly and has fine dynamic tracking characteristic and accuracy.