基于子模块电容电压预估的MMC分段电压平衡优化控制

发布时间：2018-05-27 21:43

本文选题：高压直流输电 + 模块化多电平换流器　；参考：《高电压技术》2015年07期

【摘要】：随着高压直流输电系统电压等级和输送容量的提升,对模块化多电平换流器的电容电压平衡控制提出了更高的要求。为了实现对高压大容量模块化多电平换流器电容电压的优化控制,基于桥臂子模块分段控制思想,采用分段电容电压排序控制方法。首先,分析了段内和段间电容电压平衡机理,提出了段间电压平衡控制策略;其次,将MMC开关频率分为两部分,分别分析了各部分开关频率的影响因素,提出了基于子模块电容电压预估的段内电容电压平衡优化控制策略,以降低器件的等效开关频率;最后,基于PSCAD/EMTDC的仿真结果表明,在有效保证电容电压平衡的条件下,等效开关频率降幅可达25%,从而验证了相关理论分析的正确性和控制策略的有效性。
[Abstract]:With the increase of voltage level and transmission capacity of HVDC transmission system, higher requirements are put forward for capacitor voltage balance control of modularized multilevel converter. In order to realize the optimal control of capacitor voltage of high voltage and large capacity modularized multilevel converter, based on the idea of segmental control of bridge arm module, the method of voltage sequencing control is adopted. Firstly, the mechanism of capacitor voltage balance in and between segments is analyzed, and the control strategy of voltage balance between segments is proposed. Secondly, the switching frequency of MMC is divided into two parts, and the influencing factors of switching frequency in each part are analyzed respectively. In order to reduce the equivalent switching frequency of the device, an optimal control strategy of capacitor voltage balance based on submodule capacitor voltage prediction is proposed. Finally, the simulation results based on PSCAD/EMTDC show that the capacitor voltage balance can be effectively guaranteed. The equivalent switching frequency can be reduced to 25, which verifies the correctness of the theoretical analysis and the effectiveness of the control strategy.
【作者单位】：国家电网公司智能电网研究院;
【基金】：国家自然科学基金(51261130471)~~
【分类号】：TM721.1

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