兆瓦级直驱永磁风电系统低电压穿越研究

LVRT of a MW-level wind turbine unit with a direct-driven permanent magnet synchronous generator

通过对兆瓦级直驱式永磁同步风力发电机(PMSG)系统低电压穿越能力的研究,提出一种改进的直流母线电压控制策略。该策略通过调节直流电流和控制发电机的输出功率,抑制直流母线动态过电压。与传统控制策略相比,该策略中升压斩波变换器采用电流内环、直流母线电压外环的双闭环控制结构;网侧逆变器采用电流内环和转速外环的双闭环控制结构。仿真结果表明,该控制策略可有效提高PMSG系统的低电压穿越能力。

By studying the low voltage ride through （LVRT） capability of a MW-level variable speed wind turbine unit with a direct-driven permanent magnet synchronous generator （PMSG）, an improved DC link voltage control strategy was proposed. This strategy can suppress dynamic over-vohage at DC buses by adjusting DC current and controlling the generator output. Compared with the traditional control strategy, the improved one uses the double closed-loop control structure with the current inner loop and the DC link voltage outer loop in the boost chopper converter. And its inverter has also the double closed-loop structure with the current inner loop and the rotating speed outer loop. The simulation results show that the improved control strategy can effectively improve the LVRT capability of a variable speed wind turbine unit with a PMSG.