Abstract：This paper presents the structural characteristics and operating principles of modular multilevel converters. Considering the actual requirements, SPWM pulse sequence suitable for modular multilevel converter is analyzed in detail. Two pulse modulation techniques, carrier phase shifted (CPS) technique and pulse phase shifted (PPS) technique, are proposed based on the existing modular multilevel converter prototype and control system hardware. Moreover, the principles of the two corresponding modulation schemes are studied by means of simulation and experiment. Study results indicate the difference between CPS and PPS, that is, CPS generates better SPWM pulse and features with higher dc voltage utilization compared with PPS. Meanwhile, CPS will take up more resources of control chips, and has limitations caused by limited expandability of DSP. Compared with CPS, PPS has better expandability, more simply control logic, as well as less control resources requirements, so it is suitable for multiplex SPWM pulse generating.
王晓鹏, 杨晓峰, 范文宝, 郑琼林. 模块组合多电平变换器的脉冲调制方案对比[J]. 电工技术学报, 2011, 26(5): 28-33.
Wang Xiaopeng, Yang Xiaofeng, Fan Wenbao, Zheng Trillion Q. A Comparative Study of Multi-Pulse Modulation Schemes for Modular Multilevel Converters. Transactions of China Electrotechnical Society, 2011, 26(5): 28-33.
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2011, Vol. 26 
