Affiliation:
1. Polytechnic Institute Zhejiang University Hangzhou China
2. College of Energy Engineering Zhejiang University Hangzhou China
3. Center for Balance Architecture Zhejiang University Hangzhou China
Abstract
AbstractBalancing control of neutral‐point voltage (NPV) and reducing common‐mode voltage (CMV) are crucial for a three‐level neutral‐point‐clamped (NPC) inverter. NPV oscillation can be inhibited by constructing virtual vectors and adding adjustment factors to eliminate stochastic disturbances that cause unbalanced NPV. However, the adjustment factors significantly increase computational complexity and introduce a dynamic sector split instead of the traditional static one. Moreover, constructing virtual vectors prompts a considerable rise in CMV. Therefore, this paper proposes a virtual space vector modulation strategy for the NPC inverter that eliminates NPV oscillation and reduces CMV. The study applies the idea of carrier‐based modulation (CBM), which reduces calculation time caused by the novel strategy of adding adjustment factors. A method to determine the maximum adjustment voltage is designed to evaluate NPV regulation ability, which is analysed. The novel method and the basic VSVM are theoretically compared, and it is proved that the novel method has better NPV regulation capability than the basic VSVM under high modulation ratio and high power factors, such as in motors systems.
Funder
National Natural Science Foundation of China
Publisher
Institution of Engineering and Technology (IET)
Subject
Electrical and Electronic Engineering