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模块化多电平换流器(modular multilevel converter,MMC)中的子模块电容相互独立,电容电压的均衡完全依赖于均压控制,而均压控制的复杂程度又直接取决于MMC子模块数目,随着子模块数目的增加,均压控制对计算量和数据采集速度、精度的要求日趋严苛,由此带来了一系列子模块电容均压问题.为解决该问题,该文提出一种具备自均压能力的MMC拓扑,在保留MMC模块化特性的同时,在任意相邻子模块电容间增加了辅助均压回路,使得MMC在子模块投切过程中自发地实现电容电压的均衡.该文介绍所提出新型MMC拓扑的均压原理、调制策略、参数和阻尼电阻设计方法,并提出电容电压波动程度指标和集中程度指标,用于评估新型拓扑与传统半桥MMC拓扑的均压效果,通过PSCAD/EMTDC下的仿真结果验证所提出新型自均压拓扑和调制策略的有效性.“,”As the sub-module capacitors are independent of each other,voltage balancing control is necessary for the conventional modular multilevel converter (MMC) topology.With the number of sub-modules increasing,the complexity of voltage balancing control,involving massive computation as well as demand for critical high speed and accuracy of signal acquisition,stands out.A novel topology of MMC with voltage self-balancing ability was proposed to solve the problem.The topology can automatically keep the capacitor voltage balanced through the auxiliary voltage-balancing circuit inserted between the adjacent sub-modules.The working principle,modulation strategy,auxiliary device selection and damping resistance design of the novel topology were introduced,corresponding fluctuation index and concentration index are also produced to evaluate the voltage-balancing effect of the two topologies.Simulation results in PSCAD/EMTDC validate the voltage self-balancing ability and the proposed modulation strategy of the novel topology.