永磁直驱变速恒频风电系统并网逆变器研究

Research on Grid-connected Inverter in Direct-driven Permanent Magnet Wind Power System

针对永磁直驱风电系统,采用全功率脉宽调制(PWM)逆变器实现变速恒频并网。并网逆变器采用基于电网电压定向的矢量控制策略。构建电压外环和电流内环,电压外环用于稳定直流电容电压,电流内环实现有功能量和无功能量的解耦输出。仿真和实验均表明该控制方法可实现系统单位功率因数运行,注入电网电流正弦度较高,并网电流总谐波畸变率(THD)低于5%,且系统具有较好的动、静态性能。

A direct-driven wind turbine with permanent magnet synchronous generator （PMSG） model connected with grid is established to study the issues on parallel, the grid voltage oriented control strategy is presented.The voltage feed-forward out loop and current decouple inner loop are introduced.PI controller is applied to both loops under d,q synchronous reference frame.And this control strategy is set up in Matlab/Simulink and hardware experiment,the re- suits verify that the energy is decoupled to output.The grid-connected inverter can operate under unity power factor. The output current to grid can be with great characteristics of sine and total harmonic distortion（THD） is less than 5%.