| 引用本文: | 曹鑫巍,任文明,王炜信.基于二次谐波环流注入方法的混合MMC电容电压平衡控制策略[J].电力自动化设备,2021,41(11): |
| CAO Xinwei,REN Wenming,WANG Weixin.Capacitor voltage balancing control strategy of hybrid MMC based on second-order harmonic circulation injection method[J].Electric Power Automation Equipment,2021,41(11): |
|
| 摘要: |
| 当高压直流输电系统直流侧电压降低时，混合模块化多电平变换器(MMC)将工作在过调制状态，面临电容电压不平衡的问题。分析过调制状态下混合MMC中半桥与全桥子模块电容充放电过程与能量变化，提出一种简化的二次谐波环流参考幅值的生成方法。采用二次谐波环流注入方法避免混合MMC中半桥与全桥子模块电容电压不平衡的发生，实现半桥与全桥子模块电容在一个周期内的充放电平衡，使混合MMC在直流电压降低时继续传输有功功率。仿真与实验结果表明，所提出的二次谐波环流注入方法能够有效实现混合MMC在过调制状态下的电容电压平衡。 |
| 关键词: 高压直流输电 混合模块化多电平变换器 过调制 电容电压平衡 二次谐波环流 |
| DOI：10.16081/j.epae.202108002 |
| 分类号:TM721.1;TM46 |
| 基金项目: |
|
| Capacitor voltage balancing control strategy of hybrid MMC based on second-order harmonic circulation injection method |
|
CAO Xinwei, REN Wenming, WANG Weixin
|
|
Avic China Aero-Polytechnology Establishment, Beijing 100028, China
|
| Abstract: |
| The hybrid MMC(Modular Multilevel Converter) operates in over-modulation state when DC voltage decreases in HVDC(High Voltage Direct Current) transmission system, facing the problem of capacitor voltage imbalance. By analyzing the charging and discharging process and energy change of capacitor between HBSM(Half Bridge SubMo-dule) and FBSM(Full Bridge SubModule) of hybrid MMC in over-modulation state, a simplified method for generating the reference amplitude of the second-order harmonic circulation is proposed. By second-order harmonic circulation injection method, capacitor voltage imbalance between HBSM and FBSM in hybrid MMC is avoided, the charging and discharging balance of HBSM and FBSM capacitors in one fundamental cycle is realized, so that the hybrid MMC can continue to transmit active power when DC voltage decreases. The simulative and experimental results show that the proposed method can effectively achieve capacitor voltage balance of hybrid MMC under over-modulation state. |
| Key words: HVDC power transmission hybrid modular multilevel converter over-modulation capacitor voltage balance second-order harmonic circulation |
