电网电压不平衡时基于直接谐振调节的双馈感应风电系统联合控制策略

Coordinated Control Strategy for a DFIG Generation System Under Unbalanced Grid Voltage Conditions Based on Direct Resonant Regulation

采用直接谐振调节技术,并兼顾考虑网侧变流器辅助功能,给出转子侧变流器和网侧变流器的联合控制策略,以期最大限度提升双馈发电系统综合运行能力。直接谐振控制技术以目标电磁量作为被控量,在正转同步速dq坐标系中通过谐振调节器直接获得所需的参考电压矢量,因此无需电流和电压的正、负序分解以及负序电流指令计算环节,即可实现网侧、转子侧电流的统一调节,并可显著增强控制系统对电机参数变化的适应性。仿真和实验研究表明:所设计的直接谐振调节技术在电网电压不平衡下提供准确的电流调节,并可严格地实现双馈发电系统在不平衡电网下的联合控制策略。

In order to develop the operation performance of the overall DFIG generation system, taking into account the GSC's auxiliary control, a coordinated control strategy with the direct resonant regulation has been presented in this paper. The selected electromagnetic quantities according to the target are used as the controlled variables for the resonant regulator in the positive synchronous reference frame so as to approach the commanded voltages. As a result, the rotor and GSC currents can be regulated without sequential separations and reference calculations. Besides, the proposed method can enhance the adaptability to generator parameters variations. Simulated and experiment results demonstrate the availability of the proposed direct resonant control methods for grid- and rotor-side converter.