基于变桨距和转矩动态控制的直驱永磁同步风力发电机功率平滑控制

Power Smoothing Control Strategy of Direct-driven Permanent Magnet Synchronous Generator for Wind Turbine With Pitch Angle Control and Torque Dynamic Control

风能的不确定性以及风轮机自身特性使风力发电机输出有功功率随风速变化而波动,影响风电机组输出电能质量,严重时还会影响电网运行稳定性。在分析变桨变速直驱永磁同步风力发电机运行特性的基础上,提出了在全风速范围内结合风力机变桨控制和发电机变速控制的发电机有功功率平滑控制策略。考虑到风能的随机性及直驱风能发电系统很强的非线性,设计了基于模糊理论的变桨距控制器和发电机转矩动态滑模控制器。对一台采用该控制策略的直驱永磁同步风力发电机的运行行为进行仿真研究。结果表明,提出的模糊变桨距控制能有效控制发电机转速运行范围,动态滑模控制能使发电机输出平滑的有功功率。与传统最大风能跟踪控制策略相比,所提出的控制方案能有效降低直驱永磁同步风力发电机输出有功功率的波动,控制发电机转速运行范围。

The uncertainty of wind energy and the inherent features of the wind turbine make the output active power of the wind-power generator fluctuate with the change of the wind speed, which affects the output power quality of the wind turbine and even the stability of the power grid. Based on analyzing of the operational characteristics about the direct-driven permanent magnet synchronous generator （DD-PMSG）, an active power smoothing control strategy had been proposed through the pitch angle control and variable speed control of the generator in all operating regions. Considering the stochastic behavior of the wind energy and the highly nonlinear feature of the DD-PMSG, the pitch angle controller had been investigated based on the fuzzy theory and the generator torque dynamic sliding-mode controller. The operational characteristics of a DD-PMSG with the fuzzy pitch angle control and the torque dynamic sliding-mode control were studied through the computer simulation. The simulation results show that the speed operation range of the wind turbine can be effectively controlled by the fuzzy pitch angle control strategy and the output active power of the generator can be smoothed by the dynamic sliding-mode control strategy. Compared with the traditional maximum power point tracking （MPPT） control strategy, the proposed control strategy can effectively reduce the output active power fluctuations of the DD-PMSG and limit the operation range of the generator speed.