Diode-rectifier-based high voltage dc (DR-HVdc) systems can be a promising low-cost solution for exporting wind power from remote offshore wind farms to onshore power systems. Industrializing the offshore DR-HVdc requires technical maturation, achievable through in-depth studies and pilot experiments. Deployment of offshore DR-HVdc systems may entail a fundamental change of control philosophy in wind turbine (WT) converters from grid-following control to grid-forming. This article proposes a new grid-forming control for DR-connected offshore WT converters. The proposed controller uses two sequential control loops to regulate WTs’ active power, and maintain the frequency and voltage of the offshore ac network. The first control regulates the active-power mismatch of each WT into a voltage angle deviation, which leads to a frequency change. The second control adjusts the WT's alternating voltage magnitude to counteract the frequency change. An internal current control loop is used to limit the fault current and eliminate high-frequency resonances in the system. The proposed control is verified by electromagnetic transient simulations, including fault-ride through, WTs power change, reactive power disturbance, and WTs outage.

中文翻译：

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连接到基于二极管整流器的HVdc系统的海上风力发电机的控制

基于二极管整流器的高压直流（DR-HVdc）系统可以成为将风能从偏远的海上风电场输出到陆上电力系统的低成本解决方案。海上DR-HVdc的工业化需要技术的成熟，这可以通过深入的研究和试点实验来实现。海上DR-HVdc系统的部署可能需要对风力涡轮机（WT）转换器的控制原理进行从电网跟随控制到电网形成的根本改变。本文为DR连接的海上WT转换器提出了一种新的网格形成控制。拟议的控制器使用两个顺序控制回路来调节WT的有功功率，并保持离岸交流网络的频率和电压。第一控制将每个WT的有功功率失配调节为电压角偏差，这导致频率变化。第二个控件调整WT的交流电压幅度以抵消频率变化。内部电流控制环路用于限制故障电流并消除系统中的高频谐振。通过电磁瞬态仿真，包括故障穿越，WTs功率变化，无功功率干扰和WTs中断，对提出的控制进行了验证。