中文摘要：

为实现电网不平衡条件下直驱风电系统低电压穿越，通过研究含超级电容器储能单元的系统运行特性，建立超级电容器储能单元小信号模型，实现精准的充放电控制，确保系统安全稳定运行。提出风电系统中储能容量的确定方法，研究适合于该系统的低电压运行的控制策略，包括限制机侧变流器有功输出以及调整网侧变流器有功无功分配，为电网提供无功支撑。提出新的频率自适应正序电压分量检测法，为变流器运行提供精准快速的响应信号，提高系统鲁棒性。通过仿真验证含超级电容器储能的直驱风机系统及其控制策略的可行性。

英文摘要：

To realize low voltage ride-through of direct-drive wind generator under unbalance condition of through researching system operating characteristics of super capacitor energy storage super capacitor energy storage unit was established, realizing precision control of the c unit, the small signal the grid, model of harging and discharging to ensure the safe and stable operation of the system. The method determining energy storage capacity of wind generator was put forward. The low voltage running control strategy was studied, such as limiting active output of machine side converter, adjusting the active and reactive power distribution of grid side converter, providing reactive power support for grid. Also a new detection method of frequency adaptive positive sequence voltage component was put forward to provide accurate and fast response signal for converter running and improve the system robustness. The feasibility of direct-drive wind generator with super capacitor energy storage and the control strategy was verified through the simulation results.