不平衡网压下抑制MMC模块电压波动的环流注入方法

发布时间：2018-05-12 19:30

本文选题：不平衡网压 + 电压波动　；参考：《电力系统自动化》2017年09期

【摘要】：过高的子模块电压的波动会增加模块化多电平变流器(MMC)的体积及成本,甚至影响系统的安全运行。不平衡电网电压不仅对MMC的功率传输、环流控制造成影响,负序电压、负序电流的出现会加剧子模块电压的波动。为了保证系统运行的稳定,利用环流注入来有效地降低不平衡发生期间子模块的电压波动。首先通过推导不平衡网压情况下桥臂模块电压表达式,计算出环流注入表达式以降低模块电压波动。再分析对模块电压波动及直流侧脉动的作用效果,选择对表达式中负序2倍频环流及零序2倍频环流进行有效控制。以系统控制目标k及不平衡度ε为变量,绘制不同环流控制下三相模块电压波动三维图并对比控制策略作用结果。最终,通过MATLAB仿真及实验平台的结果,验证了环流注入算法的可行性及理论分析的有效性。
[Abstract]:Too high voltage fluctuation of the sub-module will increase the volume and cost of the modularized multilevel converter MMCs, and even affect the safe operation of the system. Unbalanced grid voltage not only affects the power transmission and circulation control of MMC, but also increases the fluctuation of submodule voltage due to the emergence of negative sequence voltage and negative sequence current. In order to ensure the stability of the system, circulation injection is used to effectively reduce the voltage fluctuation of the sub-modules during the occurrence of the imbalance. Firstly, the voltage expression of the bridge arm module under unbalanced grid voltage is derived, and the circulation injection expression is calculated to reduce the voltage fluctuation of the module. The effect of voltage fluctuation and DC side pulsation is analyzed, and the negative order 2 times circulation and zero sequence 2 double frequency circulation are selected to control effectively. Taking the system control target k and unbalance 蔚 as variables, the three dimensional diagram of voltage fluctuation of three-phase modules under different circulation control is drawn and the results of control strategy are compared. Finally, the feasibility of the circulation injection algorithm and the effectiveness of theoretical analysis are verified by the MATLAB simulation and experimental results.
【作者单位】：北京交通大学国家能源主动配电网技术研发中心;
【基金】：北京市科技计划资助项目(Z161100000716003)~~
【分类号】：TM46

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