Investigation of a Four Level Voltage Active Gate Driver for Loss and Slope Control of SiC MOSFETs

Abstract

denne masteroppgaven blir en styrekrets for silikon karbid metall-oksid-halvleder felteffekttransistorer (SiC MOSFET) introdusert. Denne styrekretsen introduserer midlertidige spenningsnivå som kan styres både i lengde og i spenningsamplitude. Evnen til denne styrekretsen til å påvirke svitsjingen til en SiC MOSFET blir undersøkt via simulerte og eksperimentelle dobbel puls tester. I simuleringene blir tre forskjellige varianter av en model for C3M0075120D SiC MOSFETen fra Wolfspeed undersøkt. For ˚a gjennomføre simuleringene ble en dobbel puls test implementert i LTSpice og evalueringsfunksjonalitet ble implementert via Python. I eksperimentene blir C3M0075120K SiC MOSFETen fra Wolfspeed brukt. En prototype av stryekretskonseptet ble utviklet for ˚a gjennomføre eksperimentene. Basert på simuleringene og eksperimentene så er evnen til stryekretskonseptet tilå påvirke svitsjingen til en SiC MOSFET bekreftet.

In this Master Thesis, a four level voltage active gate driver is introduced and tested with both simulations and experiments. The switching performance can be controlled by introducing an intermediate voltage level at turn-on and turn-off, controllable in both voltage amplitude and duration. A thorough simulation study was performed using a double pulse test circuit created in LTSpice, and evaluation functions, created in Python. The simulation study used three different models for the C3M0075120D Silicon Carbide (SiC) power Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET) from Wolfspeed. Based on the simulation study, the efficacy of the active gate driver concept was proved. An exemplary selection of intermediate voltage level duration and a single voltage amplitude value was tested for the experiments. Experimental Double Pulse Tests (DPTs) were performed, examining the turn-on switching transient. In order to facilitate these experiments, a printed circuit board prototype of Active Gate Driver (AGD) was created. In addition, a DPT setup and gate driver control software were provided to perform the experimental DPTs. For the experiments, the C3M0075120K SiC power MOSFET from Wolfspeed was used. The measurement data from the experiments were processed and evaluated using Python functions created for these tasks. Based on the experimental results, the AGD prototype can influence the turn-on switching transient of the Device Under Test (DUT).