直驱风力发电故障穿越控制方法综述

Review of fault ride-through control for direct-drive wind turbine

首先根据电网故障特征,分析了直驱风力发电机组在故障运行条件下的功率关系,根据分析结果将电网故障情况下机组实现故障穿越所面临的问题总结为由电网电压正序分量有效值下降带来的"有功不平衡"和电网电压负序分量带来的"功率波动"2类问题。在此基础上,对目前直驱风力发电机组的故障穿越方法进行了总结和分类,将"有功不平衡"控制策略分为减小发电机的输出功率来减小换流器的输入功率、在直流母线处消除不平衡功率、增大网侧换流器输出功率能力3种方法;将"功率波动"控制策略分为消除并网电流负序分量和消除直流母线电压纹波2种方法,并分析了不同方法的优缺点。根据现有方法的优缺点对直驱风力发电机组故障穿越控制方法的研究方向进行了展望。

The power relationship of direct-drive wind turbine operating under fault conditions is analyzed based on the characteristics of grid fault and the problems existing in the fault ride-through of unit under fault conditions are classified into two categories：active power imbalance and power fluctuation. The fault ride-through methods of direct-drive wind turbine are summarized and classified. The control strategies for active power imbalance are classified into three types：reduce the input power of converter by limiting the output power of generator,eliminate the power imbalance at DC-bus and increase the power output capability of grid-side converter. The control strategies for power fluctuation are classified into two types： eliminate the grid-side negative sequence current and eliminate the second-order ripple of DC bus voltage. The advantages and disadvantages of each control strategy are analyzed,based on which,the research direction of fault ride-through control for direct-drive wind turbine is prospected.