说明：  对基于模块化多电平换流器作为逆变器采用最近电平逼近调制模式时的谐波分量进行分析，选取逆变器上、下桥臂电流，相间环流及交流输出电压波形作为研究 对象，通过理论推导出上、下桥臂电流主要具有直流分量、基波分量及 2 次谐波分量;相 间环流仅含有偶次谐波;交流输出电压波形仅含有奇次谐波。
(Based on the analysis of the harmonic components of the modular multilevel converter when the closest level approach modulation mode is adopted as the inverter, the upper and lower bridge arm currents, inter phase circulation and AC output voltage waveforms of the inverter are selected as the research objects, and the current of the upper and lower bridge arm mainly includes DC component, fundamental component and second harmonic component; There are only even harmonics in the inter phase circulating current and odd harmonics in the AC output voltage waveform.)