摘  要：為抑制三電平逆變器共模電壓，以二極管鉗位式拓撲為例，分析其共模電壓產生機理并提出一種抑制共模電壓的簡化三電平5段式空間矢量脈寬調制算法。該算法通過選取輸出共模電壓幅值小的基本電壓矢量參與調制來抑制共模電壓。仿真和實驗結果表明，所提算法將共模電壓最大幅值抑制到Vdc/6，比傳統一般算法、抑制共模電壓的7段式、7段式算法分別減少2/3，1/2，0，且可以克服上述3種算法輸出共模電壓幅值隨其調制度變化而變化的缺點。

關鍵詞：二極管鉗位式三電平逆變器；空間矢量脈寬調制；共模電壓；5段式算法

文獻標志碼：A     文章編號：1674-5124（2015）12-0106-05

Common-mode voltage analysis and reduction for three-level inverter

GAO Fang， GAO Rui

（College of Engineering and Technology，Changchun Vocational Institute of Technology，Jilin 130033，China）

Abstract: In order to reduce common-mode voltage of three-level inverter， this paper takes diode-clamped topology for instance， analyzes its common-mode voltage generation mechanism and proposes a simplified common-mode voltage reduction three-level five-segment space vector pulse width modulation algorithm（SVPWM）. To reduce common-mode voltage， this algorithm selects proper basic voltage vectors to modulate. Simulative and experimental results show that， the proposed algorithm can suppress the maximum value of common-mode voltage to one sixth of DC voltage source value， and decrease respectively about two thirds， one second， zero comparing with traditional space vector modulation， seven-segment， five-segment algorithm. Meanwhile， it can overcome the disadvantage of common-mode voltage value varies with the modulation index of above three algorithms. 

Keywords: diode-clamped three-level inverter； SVPWM； common-mode voltage； five-segment algorithm