Improved Control of DFIG Wind Turbines for Operation with Unbalanced Network Voltages
Improved Control of DFIG Wind Turbines for Operation with Unbalanced Network Voltages
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DOI：
10.1109/08ias.2008.153
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发表时间：
2008-10
期刊：
影响因子：
--
通讯作者：
W. Qiao;R. Harley
中科院分区：
文献类型：
--
作者：
W. Qiao;R. Harley
许多风力涡轮机发电机（WTG）安装在偏远的农村地区，在那里电网通常较弱，其特征在于不平衡的电压条件。如果在控制系统中不考虑电压不平衡，将导致电能质量和风力发电机系统的运行性能差。提出了一种新的控制方案，以改善运行性能的双馈感应发电机（DFIG）的涡轮机在电网电压不平衡的条件下。DFIG的转子侧变流器（RSC）和电网侧变流器（GSC）在正（dq）+参考系以及负（dq）-参考系中被控制。（dq）+参考系中的RSC和GSC的控制与平衡网络条件下的常规控制相同。在（dq）参考系中的RSC的补充控制最小化由不平衡的网络电压引起的DFIG的电磁转矩脉动;在（dq）参考系中的GSC的补充控制有助于平衡DFIG的总输出电流。在PSCAD/EMTDC中对一台接入电网电压不平衡的3.6 MW双馈风力发电机涡轮机进行了仿真研究。结果表明，该控制策略改善了双馈风力机涡轮机系统的运行性能。
Many wind turbine generators (WTGs) are installed in remote, rural areas, where the power grids are usually weak, characterized by unbalanced voltage conditions. If the voltage unbalance is not taken into account in the control system, it will cause poor power quality and poor operating performance of the WTG systems. This paper proposes a novel control scheme to improve the operating performance of a wind turbine equipped with a doubly fed induction generator (DFIG) under unbalanced network voltage conditions. The rotor-side converter (RSC) and grid-side converter (GSC) of the DFIG are controlled in a positive (dq)+ reference frame as well as in a negative (dq)- reference frame. Control of the RSC and GSC in the (dq)+ reference frame is the same as the regular control under balanced network conditions. The supplementary control of the RSC in the (dq)- reference frame minimizes the electromagnetic torque pulsations of the DFIG caused by the unbalanced network voltage; the supplementary control of the GSC in the (dq)- reference frame contributes to balance the total output currents of the DFIG. The proposed control scheme is implemented in PSCAD/EMTDC on a 3.6 MW DFIG wind turbine connected to a power network with unbalanced voltage. Results show that it improves the operating performance of the DFIG wind turbine system.