Research On SiC MOSFET Characteristics And Application

Silicon carbide,as a main member of the third generation of semiconductor material, has characteristics such as wide band gap, high thermal conductivity, high saturated electron drift velocity,comparing to silicon and gallium arsenide.Taking SiC MOSFET as an example, because of its high switching frequency, high temperature,low on-resistance and other properties,it becomes a very popular component of high-voltage high-power switching devices.This paper chooses the proper SiC MOSFET model by leveraging static characteristics and switching characteristics of SiC MOSFET.Nowadays domestic researches on SiC MOSFET is still in an early stage and there is no mature drive circuit.This paper focuses on designing the drive circuit based on the selected SiC MOSFET model, so that the SiC MOSFET can get an relatively ideal waveform to turn on and off;In the meanwhile, this paper designs two parallel BOOST circuits using boost chopper circuit topology:one using silicon carbide power devices, the other one using silicon-based power devices, then does the switching experiments and the junction temperature experimentsunder a certain test environment. Experimental results verify the drive circuit design is practical. More important, the comparison of experimental dataproves the advantage of SiC MOSFET over Si MOSFET in terms of switching frequency, turn on and off performance and junction temperature.In the past, multiple MOSFET series-parallel uses DSP or other external devices to generate multiple PWM waves to achieve one-to-one power devices’ turn on or off.However, the asymmetric circuit can result in the driving signalsarrive gates at different time, which further leads tounsynchronized turn on or off on multiple MOSFETs.Based on some MOSFET series-parallel researches that have already been published, this paperproposes an easy-to-drive series topology. Itachievesmultiple MOSFETs series with single external drive, thus solving multiple drive signals’ gate arrival time inconsistency caused unsynchronized turn on or off, then applying it to boost chopper circuit.