Research On Modeling And Simulation Of Control System In Direct-drive Wind Turbine

As in the depletion of renewable energy, people began to pay attention to the development and utilization of new energy. Wind power as the main force of the new energy, has achieved rapid development in recent years. Due to the high rate of energy conversion and flexible network power control, direct-drive wind power generation system becomes one of the most promising wind power generations and obtains extensive attention from researchers.In the direct-drive wind power system, full-power converter connects generator and electric, variable frequency energy is converted to the constant frequency constant voltage energy, to achieve the rapid adjustment of generator output current and power factor and reduce the harmonic pollution on power. Meanwhile, it plays a very active role in the efficient and stable operation of the entire wind power generation system. Therefore, the effective control of the converter is the core of the power conversion; master the technology can promote the development of China’s wind power business.The paper main makes research on the mathematical model of dual PWM converter in the direct-drive wind power system and its control strategy, and verified the correctness of the theory of the study by simulation experiment. The specific content of the paper is as follows: Ⅰ. Firstly, the research make introduction on the current situation of wind power; focuses on the direct-drive inverter topology and control technology, build a mathematical model of permanent magnet synchronous generator, the PWM rectifier and the converter DC link, so laid a foundation for the later study.Ⅱ. According to the mathematical model, study respectively on the machine side converter and grid side converter control strategy. Machine-side converter use the rotor magnetic field oriented vector control strategy, Network-side converter use the grid voltage-oriented control strategy, decoupling control of active power and reactive power; Parameters such as the calculation of the PI parameters of the control system, the network side of the filter inductor, the DC side capacitance, provides the reference for the choice of system parameters; Finally, study the protection measures to be taken to the DC side when the three-phase power grid voltage drop.Ⅲ. Build a simulation model of the entire direct-drive wind power generation system on the MATLAB/Simulink simulation platform and make simulation analysis on two cases of normal grid voltage and grid voltage drop. Simulation results show that:In the case of normal grid voltage, the control strategy can achieve the maximum power point tracking and maintain the stability of the DC voltage; In the case of power grid voltage drop, DC capacitor will bring over voltage. By protective measures can solve this problem effectively.