Design On The Variable Pitch Control System Of Mw Direct-driven PM Wind Generator

In recent years, wind energy has drawn worldwide attention as the world’s fastestgrowing renewable energy source. Benefit from the ceaseless development of infor-mation technology and automatic control technique, the development of wind powergeneration is in fast progress. Its single-machine capacity develops from several ki-lowatts up to more than one megawatts per unit，and control mode from fixed bladewith generator from stall type to variable-pitch type up to the variable-speed type. Inthe wind power market, direct-drive permanent magnet synchronous wind turbinegenerators have been developing rapidly for simple structure, low maintenance costs,high conversion efficiency and high reliability.The paper is based on the object of “localization of MW wind turbine generatorscontrol system”. Take the2MW XE93-2000direct-drive permanent magnet syn-chronous wind turbine generator as the specific research object, this paper carries outits research on modeling and simulation, and makes lots of design and improvementworks for the variable-pitch control system.First, the paper describes the operation principle of variable-pitch control sys-tems of variable speed wind generator. The nonlinear relation ofC pwith λ and βis educed by studying the aerodynamic characteristics of wind turbine machines,which provides theoretical base for the control strategy of variable-pitch wind powergeneration.Then, according to the characteristics of direct-drive permanent magnet windturbine generator, this paper separately established the mathematical models of aero-dynamic part, transmission part of the wind turbine machine and the part of di-rect-drive permanent magnet generator. Based on that, the mathematical model of thewhole direct-drive PM generators was established under the environment of Mat-lab/Simulink as well as the simulation and debugging.At last，This paper makes a total design and project approach for the variablepitch servo control system of XE93-2000direct-drive PM generators. The systemchooses independent electric variable-pitch method. By comparative selection, thevariable-pitch control system adopts DC electric pitch control system. On this basis,the paper also has made lots of detailed design and improvements on the power dis-tribution circuit, logic control circuit, backup power supplies, safety chain circuit,battery management unit and the circuit of pitch motor start-up etc.