基于Matlab/Simulink的小型风力发电机电能质量指标仿真计算与分析

Simulation and analysis of power quality indexes for small wind turbines based on Matlab/Simulink

以小型风力发电机组为研究对象,依据IEC标准和国家标准,采用Matlab/Sumilink仿真与电能数据采集实验相结合的方法评价电能质量指标,提出影响电能质量评价指标的因素及优化对策,为提升小型永磁风力发电机组电能质量给予指导依据。研究表明:永磁发电机齿槽数和极对数等结构参数发生改变时,转子转动惯量增大导致频率偏差比增幅达1.37倍,并对发电机内部三相对称性有一定不利,转子磁通量增大使气隙磁场谐波畸变恶化但电压偏差减小;另外,风电机组防止超负荷提高转速可降低电压波动,同时限制高转速运行可避免三相不平衡度超标;此外,长时间温升超标运行导致的发电机绝缘老化和退磁,易使电压偏差和频率偏差比增幅分别达2.03倍和1.36倍。

This study order the small wind turbines as the research object. The data acquisition and analysis system is adopt to collected electrical data, while the Matlab/Sumilink is applied to this process simulation. And according to IEC standards and national standards, the power quality indexes are evaluated. The study would give the influencing factors of power quality and its optimizing countermeasures, so that the guiding basis can be provided for power quality improvement of small permanent magnet wind turbines. It has shown that when the number of cogs and pole pairs for PMSG changes, the increment of the rotor inertia lead to the increasing range of frequency deviation ratio reached 1.37 times and have bad effects on the three-phase symmetry of voltage. Besides, with the increment of the rotor flux linkage the total harmonic distortion rate of gap magnetic field will improves but the voltage deviation will be lower. Furthermore, the raising rotor speed or avoiding overload operation in wind turbines can mainly reduce voltage fluctuations, while the rotor speed restriction can avoid excessive three-phase imbalance. In addition, the insulation ageing and demagnetization because of chronically over-temperature operation make the voltage deviation enlarges 2.03 times and the frequency deviation ratio increases 1.36 times.