双三电平永磁直驱风力发电系统控制策略研究

摘要

为满足变流器容量需求并获取较低的电流谐波指标,降低开关损耗,达到良好的并网要求,直驱式风力发电系统采用永磁同步发电机(PMSG)和双三电平变流器相结合的拓扑结构.基于PMSG d,q坐标系下的数学模型,机侧变换器运用简化的空间矢量脉宽调制技术并结合PMSG的最大转矩电流比控制策略,充分利用凸极效应,提高系统运行效率,网侧变换器采用电压电流双闭环控制策略.利用Matlab软件建立直驱式永磁同步风力发电系统的仿真模型,并对风速突变时系统的动态特性进行研究.仿真结果表明,所建立模型具有较好的动态特性并验证了控制系统的正确性及有效性.%To meet the requirement for the capacity, low current harmonic level and low switching loss, direct-drive wind power generation system employed the topology which combined the permanent magnet synchronous generator (PMSG) and dual three-level PWM full-size converter.Based on d,q axis mathematical model of PMSG,in order to take full advantages of saliency effects, improve efficiency, the generator side adopts simplified space vector pulse width modulation technology combined with maximum torque per ampere control scheme.The grid side employes the dual close-loop control strategy which are the inner current-loop and the outer voltage-loop. The model of direct-drive wind power generation system is realized with the engineering software, Matlab for the case of wind speed stepping change shows the excellent dynamic performance of the model, in the same time, verifies the correctness and feasibili ty of the control strategy.