Sudden increases in the dc-link voltage, caused by ac grid side voltage drops, can lead to potential damage in the equipment. Therefore, dc choppers are widely used in offshore wind power links to absorb the excess energy and keep the voltage within safe margins. This article investigates the existing chopper topologies and summarizes their advantages and disadvantages. On this basis, a novel dc chopper topology with both centralized and distributed resistances is proposed. It is a combination of two mainstream chopper topologies and gives the flexibility to tradeoff among the pros and cons of them. In this way, the proposed topology achieves great electromagnetic interference performance, precise power control, and very small system disturbance. In addition, the maximum power dissipation of the distributed resistance is reduced by 75%. The switching frequency and the loss of insulated gate bipolar transistors (IGBTs) are also decreased. Finally, the claimed attributes of the proposed topology are verified by test and simulation.

中文翻译：

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一种用于基于 VSC 的海上风电场连接的新型直流斩波器拓扑结构

由交流电网侧电压下降引起的直流母线电压突然升高可能导致设备损坏。因此，直流斩波器广泛用于海上风电链路，以吸收多余的能量并将电压保持在安全范围内。本文调查了现有的斩波器拓扑并总结了它们的优缺点。在此基础上，提出了一种具有集中电阻和分布式电阻的新型直流斩波拓扑。它是两种主流斩波器拓扑结构的组合，可以灵活地权衡它们的利弊。通过这种方式，所提出的拓扑结构实现了良好的电磁干扰性能、精确的功率控制和非常小的系统干扰。此外，分布电阻的最大功耗降低了 75%。绝缘栅双极晶体管 (IGBT) 的开关频率和损耗也降低了。最后，通过测试和模拟验证了所提出的拓扑所声称的属性。