基于混合直流换流器的海上风电送出系统的启动策略  

Startup Strategy of Transmission System of Offshore Wind Farms Based on Hybrid DC Converter

作　　者：方梓熙 艾斯卡尔[2] 蔡旭[1] 杨志千 史先强 方陈 FANG Zixi;Aisikaer;CAI Xu;YANG Zhiqian;SHI Xianqiang;FANG Chen(Key Laboratory of Control of Power Transmission and Conversion,Ministry of Education,Shanghai Jiao Tong University,Shanghai 200240,China;Xinjiang Goldwind Science&Technology Co.,Ltd.,Beijing 100176,China;Electric Power Research Institute of State Grid Shanghai Municipal Electric Power Company,Shanghai 200437,China)

机构地区：[1]上海交通大学电力传输与功率变换控制教育部重点实验室,上海200240 [2]新疆金风科技股份有限公司,北京100176 [3]国网上海市电力公司电力科学研究院,上海200437

出　　处：《高电压技术》2021年第8期2698-2707,共10页High Voltage Engineering

基　　金：国家重点研发计划(2019YFE0104800);国家电网公司科技项目(520940200010)。

摘　　要：混合型直流换流器由全控辅助换流器与二极管整流器并联构成,相比传统模块化多电平换流器(modular multilevel converter,MMC),所需子模块数目大量减少,用于海上直流输电时的经济性显著上升,但目前针对该混合换流器的预充电尚无研究。为此,提出了混合直流换流器的启动策略。首先将混合换流器的启动分为不控充电与可控充电2个阶段,针对不控充电阶段分析了子模块电容电压之间的关系,并给出了限流电阻的计算方法。针对可控充电阶段,提出了2种不同的预充电方案。第1种方案依托于参数设计,方案简单有效,但降低了拓扑的模块性,提高了应用成本。第2种方案依托于环流控制,可以不用降低拓扑的模块性,但流程更加复杂,充电速度较慢。最后在MATLAB/Simulink中构建了混合换流器模型进行仿真,仿真结果验证了启动策略的有效性。Hybrid DC converter is composed of a fully controlled auxiliary converter and the diode rectifier.Compared with the traditional modular multilevel converter(MMC),the number of submodules is greatly decreased so as to increase the economic efficiency of the offshore DC transmission.However,the research on the precharge strategy of this converter is not available in literature presently.Therefore,the startup strategy of the hybrid DC converter is proposed in this paper.Firstly,the startup process of the hybrid converter is divided into two stages:uncontrollable stage and controllable stage.For the uncontrollable stage,the relationship of the capacitor voltage of the submodules is analyzed and the computation method of the current limiting resistance is proposed.For the controllable stage,two different precharge schemes are proposed.The first scheme based on parameter design is simple and effective.But the modularity of the topology is decreased and the application cost is increased.The second scheme based on circulating current control is more flexible without sacrificing the modularity of the topology.But the precharge process is more complicated and slower.Finally,the feasibility of the proposed startup strategy is verified through the simulation models of hybrid converter in MATLAB/Simulink environment.

关 键 词：混合直流换流器 预充电过程 启动策略 柔性直流输电 海上风场 二极管整流器 

分 类 号：TM46[电气工程—电器] TM614