Research On Direct Drive Wind Power Variable Speed Constant Frequency System

Energy problem is the constant issue in people's production and life, the energy in 21th century is the more concerned focus of people. Nonrenewable energy is increasingly exhaustion, thus many countries in the world make a good effort to search new energy to meet for the need of production and life. As a kind of renewable clean energy, wind power is thought of a new ideal green energy. The major utility form of wind power is wind power. Most of wind power converter equipments and technique in our country majorly have to depand the abroad patents, and technique for actual independent intellectual property is bare, so it is an urgent matter for our country's wind power course to develope wind power converter equipments for independent intellectual property.This paper has researched all kinds of wind power system, and the results show that direct drive wind power system is considered one of the most developmental system.The dual PWM converter unit that used in this system is one of the most advantageous topology. After deeply analysised and researched for direct drive wind power system, this paper attempt to put forward a new kind of control strategy, and reassign the control functions of individual unit of converter. The following job is completed under this structure.Considering the complex characters of multivariable, nonlinearable, coupling, strong disturbance this control object has and uncertain factors existed, the model of multipole low speed permanent magnet generator is equivalent, modlling the converter unit, use SVPWM modulation algorithm, design inner current loop and outer voltage loop of this system based on PI controller, and modelling and simulation for every submodel. As the fast character and dynamic character is not very good for the conventional PI controller and considering the practicality that fuzzy self-regulation PI controller has, so this paper design fuzzy self-regulation controller.The simulation results vs. conventional PI controller's demonstrate that the optimized membership degree function based fuzzy PI control system has the character of fast, small overshoot, short rise time and good disturbance rejection,and the results show that the theory design is correct, thus provides reference for practical project.