Analysis of Vector Estimating Modulation Method to Eliminate Common Mode Voltage

Document Type : Research Article



The problem of common mode voltage in inverters can be considered as a major issue which leads to motor bearing failures. To eliminate these voltages, proposing some methods seems to be necessary. This paper has a comparative study on estimating modulation methods of eliminating common mode voltage. The main idea of these methods is based on generation of reference vector with nearest vector/ vectors with zero common mode voltage. Depending on the number of delivering nearest vectors, there are two estimating methods. For the reference method, reference vector is synthesized only by the nearest vector. But for the proposed method, the reference vector is synthesized by more than one vector. Dwell time calculations of these vectors are based on the distance between the afore-mentioned vectors and the reference vector. In this paper, some characteristics such as linear relationships among output voltage and modulation index, and also total harmonic distortion of output voltage and stator current are considered. Finally, it is concluded that the new method has more advantages such as more linear relationships and lower THD of current with respect to the reference method.


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Papers from Conference Proceedings (Published):
[8]     N. Rashidi‐rad, A. Rahmati and A. Abrishamifar, “A New Modulation Method to Eliminate Common Mode Voltages in Modular Multilevel Inverters”, in Proc.  2011 IEEE International Conference on Information and Industrial Electronics, pp. 113-116.
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