Crosstalk Analysis and Suppression of Silicon Carbide MOSFET based Three-level Neutral-Point-Clamped Inverter

This paper analyzes the gate-source characteristic of Silicon Carbide (SiC) MOSFET in Three-level Neutral-Point Clamped (3L-NPC) Inverter. To analyze the switching process of the SiC MOSFET, the bridge arm crosstalk and gate voltage oscillation phenomenon of the 3L-NPC, the mathematical model of the cross-talk voltage based on 3L-NPC is introduced. The switching period of the SiC devices is analyzed which include the crosstalk and parasitic oscillation. According to this, the snubber circuit and the gate voltage surge suppression circuit are designed, which also include overcurrent and overvoltage protection. The experiment shows good results of the proposed analyzes. And the conclusion can be extended to multilevel Inverter.

I. Introduction

The 3L-NPC inverter was proposed for the first time in [1]. With the development of this new topology, multilevel inverters with different levels and different circuit structures are derived. Among them, the 3L-NPC topology is shown in Fig.1. The circuit is powered by a single power supply, using capacitors in series to create midpoint potentials and using diodes to clamp the neutral voltage [2].