适用于大型海上风电的谐振型飞跨电容式模块化升压变换器  

Resonant Flying Capacitor Modular Boost Converter for Large Scale Offshore Wind Power

作　　者：潘俊良 王明渝[1] Pan Junliang;Wang Mingyu(School of Electrical Engineering,Chongqing University,Chongqing,400044,China)

机构地区：[1]重庆大学电气工程学院,重庆400044

出　　处：《电工技术学报》2024年第12期3746-3760,共15页Transactions of China Electrotechnical Society

摘　　要：随着海上风电发电容量的增大与离岸距离的增加,全直流型海上风电系统的优势越发明显。高压DC-DC变换器是该系统的核心部件,承担直流升压与输电的关键功能。对此,该文提出一种适用于大型海上风电的谐振型飞跨电容式模块化升压变换器,不受大功率中频高压变压器制造工艺的限制,无变压器结构使其能工作在更高频率,减少内部无源器件,实现轻量化。在高升压比应用场景中,变换器内部大部分功率器件为二极管,可节省控制单元,并降低成本。与电流连续模式相比,当内部二极管半桥工作在电流断续模式时,该变换器能在仅增加少量通态损耗的前提下实现内部功率器件的软开关。此外,该变换器采用准方波调制时,电流断续模式能避免内部串联二极管承受高dv/dt。最后,通过样机实验验证了该变换器拓扑的可行性与参数设计方法的正确性。With the increasing saturation of offshore wind farm sites,the trend in offshore wind power is shifting towards deep-water development.The absence of reactive power loss and sub-synchronous oscillation problems makes it more suitable for large-capacity,long-distance,deep-water offshore wind farms.The high-voltage DC/DC converter is the core component of all-DC offshore wind power,connecting the collector grid and the transmission line.A resonant flying capacitor modular boost converter is proposed for large-scale offshore wind power applications.Firstly,the transformer topology is introduced,and the operating mode analysis is carried out.This converter typically uses a multiphase structure to increase the transmission power and cancel out the AC component of the current at the DC input and output during symmetrical operation.Each phase consists of two sub-module half-bridges,diode half-bridges,and flying capacitors.The sub-module half-bridge connected to the DC input is named the master-bridge,and the other is named the slave-bridge.The master-bridge and slave-bridge adopt quasi-square-wave modulation to reduce the sub-module capacitance and facilitate soft-switching.The modulation phase difference between master-bridge and slave-bridge is adjusted to change the output power.According to the relationship between master-bridge arm inductance L_(m) and slave-bridge arm inductance L_(s),the converter operates in two conditions.The diode half-bridge can operate in continuous or discontinuous current mode based on parameter designs.Then,according to the phase relationship of steady-state voltage and current in the converter’s internal AC equivalent circuit diagram and the operating mode analysis,the two design methods are presented,one where L_(s) is much larger than L_(m),and the other where L_(m) is much larger than L_(s).When L_(s) is much larger than L_(m),the continuous current mode makes the DC side voltages of the slave-bridge and diode half-bridges close to that of the master-bridge,more convenient for devic

关 键 词：海上风电 高压直流输电 DC-DC变换器 模块化 飞跨电容 

分 类 号：TM46[电气工程—电器]