适用于远距离大容量架空线输电的交叉型子模块拓扑

Topology of Cross-connected Sub-modules for Long-distance Bulk Overhead Line Power Transmission

提出了一种适用于模块化多电平换流器的具有直流故障自清除能力的交叉型子模块(CCSM)。该子模块由12个绝缘栅双极型晶体管、12个反并联二极管和4个电容组成,可分别输出4电平、2电平、0电平和-2电平。同等输出条件下,CCSM除了具有较高的经济性以外,还可在保证直流故障自清除能力的基础上为换流器提供更广泛的运行范围,尤其适用于电压等级高、输送容量大、采用架空线路传输的柔性直流输电系统。此外,还研究了基于CCSM的调制方法及电容电压平衡策略,并在PSCAD/EMTDC中搭建了仿真模型,验证了所提拓扑及控制策略的有效性与可行性。

A novel topology of cross-connected sub-module（ CCSM） with DC-fault clearance capability for modular multilevel converter is proposed and discussed. The CCSM containing 12 insulated gate bipolar transistors, 12 anti-parallel diodes and 4 capacitors, can output 4, 2, 0 and-2 electrical level, respectively. The efficiency of CCSM is as high as that of clamp-double sub-modules, while more suitable for bulk power overhead line transmission. The modulation and voltage balancing strategy is also discussed. A simulation model is built in PSCAD/EMTDC, the simulation results proving the validity and the feasibility of the proposed topology and control strategy.