具备自均压能力的模块化多电平换流器拓扑

发布时间：2019-03-15 21:24

【摘要】：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。
[Abstract]:The capacitance of sub-modules in modular multilevel converter (modular multilevel converter,MMC (Modular multilevel Converter) is independent of each other. The equalization of capacitance voltage depends entirely on the voltage-sharing control, and the complexity of voltage-sharing control depends directly on the number of MMC sub-modules. With the increase of the number of sub-modules, the requirement of computation and data acquisition speed for voltage-sharing control becomes more and more stringent, which leads to a series of capacitor voltage-sharing problems of sub-modules. In order to solve this problem, a MMC topology with self-voltage sharing capability is proposed in this paper. While preserving the modularization characteristic of MMC, an auxiliary voltage-sharing loop is added between the capacitors of any adjacent sub-module, and an auxiliary voltage-sharing loop is added between the capacitors of any adjacent sub-module. The capacitor voltage equalization of the MMC is realized spontaneously in the switching process of the sub-modules. In this paper, the voltage sharing principle, modulation strategy, parameters and damping resistance design method of the proposed new MMC topology are introduced, and the index of capacitance voltage fluctuation and concentration degree are also presented. It is used to evaluate the voltage sharing effect between the new topology and the traditional half-bridge MMC topology. The simulation results under PSCAD/EMTDC verify the effectiveness of the proposed self-voltage sharing topology and modulation strategy.
【作者单位】：新能源电力系统国家重点实验室(华北电力大学);
【基金】：国家自然科学基金项目(51607065)~~
【分类号】：TM46

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