221 / 2017-11-21 17:01:24

The Security Protection of SiC MOSFET NPC Tri-level Converter

SiC MOSFET,NPC three-level converter,voltage balanced,leakage current,overcurrent,same arm,clamping diode,asymmetric capacitor

全体主题 > Applications in renewable energy and storage, transportation, industrial drives, and grid power

In this paper, the security strategies of Silicon Carbide (SiC) MOSFET neutral point clamped (NPC) tri-level converter were discussed. Firstly, SiC MOSFET driver was designed, in which over-current protection strategy based on drain-source voltage detection was suggested. Secondly, the origin about voltage unbalance between the same arm SiC MOSFET in tri-level converter was analyzed in detail during commutation process. A novel voltage balanced circuit was proposed. The research results showed that the leakage current of clamped diode was the dominant factor, which determined SiC MOSFET voltage unbalance degree. The greater the leakage current of clamped diode was, the more obvious the voltage unbalance in same arm SiC MOSFET. The tri-level converter experiments were carried, in which different types of clamped diode and proposed voltage balanced circuit were adopted. They verified that the voltage unbalance analyses and the proposed strategy were correct and effective.