基于电压向量合成的模块化多电平换流器控制策略

介绍了模块化多电平换流器（modular multi-level converter,MMC）的拓扑结构与工作原理,提出一种基于电压向量合成的模块化多电平换流器型高压直流输电（modular multi-level converter based high voltage direct current,MMC-HVDC）控制方法.传统的模块化多电平换流器控制方法子模块投切频率高,相应的开关损耗也高.设计的电压向量合成控制法可以实现子模块工频开关投切,极大地降低了模块开关损耗.同时还针对该控制方法设计了模块均压控制策略和换流器闭环控制系统,在模块工频投切的同时模块电压也能得到良好的均压控制.仿真结果表明所设计的控制系统模块开关频率低,电压波动范围小,实现了功率的闭环控制,具备很好的理论研究价值和工程应用价值.

Research of Modular Multi-Level Converter Control Strategy Based on Voltage Vector Composition

： This paper introduced the topological structure and working principle of modular multi-level converter （MMC）, and presented a new control method for MMC-HVDC （modular multi-level converter based high voltage direct current） based on voltage vector composition. The switching frequency of sub-module was high in the traditional control method for MMC, so the switching loss was also high. In the proposed control method, the switching frequency of sub- module could be reduced to power frequency, so the module switching loss was greatly reduced. Meanwhile, the voltage balance control strategy of module and the closed-loop control system of converter were designed for the control method, in which the module voltage could obtain good control along with power frequency switching. Simulation results show that, the switching frequency of module is lower, and the voltage fluctuation range is small, in the proposed control system, which can realize the closed-loop control of power, as well as has great value in theoretical research and engineering application.