基于线性最优的MMC子模块电容电压均衡控制策略

发布时间：2018-11-20 21:37

【摘要】：为进一步优化模块化多电平换流器(MMC)子模块控制策略,尤其是能够兼顾子模块电容电压波动、桥臂环流二次谐波含量、子模块绝缘栅双极型晶体管(IGBT)投切次数和算法计算量四方面的性能,提出一种基于线性最优解的MMC子模块电容电压均衡控制策略。首先,阐述了子模块电容电压波动和子模块IGBT投切次数之间的相悖性,通过理论分析证明子模块电容电压波动与桥臂环流二次谐波含量之间也存在非线性关系,需寻找适当算法使其三者同时达到最优情况。然后,针对此目标,对传统算法进行优化,增加附加调节子模块功能,并结合子模块电容电压均衡控制策略,详细阐述了所述算法的控制流程及其优越性。最后,通过动模试验对传统控制策略、子模块电容电压均衡控制策略、所提控制策略及其他采用不同数量的附加调节子模块的控制策略进行对比。试验数据表明,所提策略可以在子模块电压波动、桥臂环流中的二次谐波含量和子模块IGBT投切次数三方面达到线性最优。
[Abstract]:In order to further optimize the control strategy of the modularized multilevel converter (MMC) submodule, especially the capacitance voltage fluctuation of the submodule and the second harmonic content of the bridge arm circulation, This paper presents a capacitor voltage equalization control strategy for submodule insulated gate bipolar transistors (MMC) based on linear optimal solution in terms of the switching times of (IGBT) and the computational complexity of the algorithm. Firstly, the contradiction between the voltage fluctuation of submodule capacitor and the number of switching times of submodule IGBT is expounded. The nonlinear relationship between the voltage fluctuation of submodule capacitor and the second harmonic content of the bridge arm circulation is proved by theoretical analysis. It is necessary to find an appropriate algorithm to achieve the optimal condition at the same time. Then, aiming at this goal, the traditional algorithm is optimized, and the function of additional regulation sub-module is added, and the control flow and its superiority of the algorithm are described in detail in combination with the capacitive voltage equalization control strategy of the sub-module. Finally, the traditional control strategy, the capacitor voltage equalization control strategy of sub-module, the proposed control strategy and other control strategies with different number of additional regulation sub-modules are compared by dynamic simulation test. The experimental data show that the proposed strategy can achieve linear optimization in three aspects: voltage fluctuation of submodule, second harmonic content in the circulation of the bridge arm and the switching times of the sub-module IGBT.
【作者单位】：国家电网公司;国网江苏省电力公司;国网江苏省电力公司电力科学研究院;
【基金】：国家自然科学基金资助项目(51377022) 江苏省自然科学基金资助项目(BK20140113) 国家电网公司科技项目(SGCC-2015-011)~~
【分类号】：TM46

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