基于电流注入法的模块化多电平换流器损耗建模

Modelling of Modular Multilevel Converter Loss Based on Current Injection Method

模块化多电平换流器(modular multilevel converter,MMC)的阀体损耗较大,MMC型柔性直流精细化电磁暂态仿真及系统效率研究需要对阀体损耗有更准确的模拟。针对现有柔性直流电磁暂态仿真中的阀体因采用等效模型导致的不存在的虚拟损耗问题,提出了基于电流注入法的柔性直流含阀体损耗电磁暂态建模方法,包括采用有限采样法实现不同运行工况下阀体损耗值的准确自动计算,参考计算结果在建模中采用电流注入法对损耗进行补偿,实现对换流阀损耗的动态跟踪与模拟。最后,通过在PSCAD中搭建柔性直流电磁暂态仿真模型,验证了所提方法的准确性,研究结果可用于精确模拟含阀体损耗的柔性直流电磁暂态建模,且通过仿真可进一步开展降损措施研究。

The valve body loss of the modular multilevel converter(MMC)is relatively large,and the refined electromagnetic transient simulation of the MMC based high voltage direct current(MMC-HVDC)requires more accurate simulation of the valve body loss for system efficiency study.Aiming at the problems of virtua losses caused by the use of equivalent models in existing MMC-HVDC electromagnetic transient simulation,a MMC-HVDC electromagnetic transient modeling method with valve body loss based on current injection method is proposed,which includes accurate automatic calculation of valve body losses under different operating conditions using the finite sampling method.Referring to the calculation results,the current injection method is used to compensate for losses in the modeling and dynamic tracking and simulation of converter valve losses are realized.Finally,the ac⁃curacy of the proposed method is verified by constructing a MMC-HVDC electromagnetic transient simulation model in PSCAD.The research results can be used to accurately simulate MMC-HVDC electromagnetic transient modeling with valve body losses,and further research on loss reduction measures can be carried out through simulation.