Research On On-line Junction Temperature Measurement Of Silicon Carbide MOSFET Based On Temperature Sensitive Electrical Parameters

As a new generation of wide bandgap power semiconductor devices,silicon carbide MOSFETs have excellent performance in high voltage,high temperature,high frequency,and low loss.Junction temperature monitoring can improve their working ability under thermal limits,making better use of device performance.High precision and fast response junction temperature measurement also helps with device state perception and real-time regulation.The temperature sensitive electrical parameter method is very suitable for online junction temperature measurement because it does not require changes to the original packaging structure and has a fast response capability at the microsecond level.However,there are significant differences in the temperature sensitive characteristics between silicon carbide MOSFET devices and traditional silicon based devices,and targeted research is needed.In this paper,taking silicon carbide MOSFET as the research object,and facing the problem of online junction temperature measurement problem in its practical application,the temperature sensitive characteristics of silicon carbide MOSFET’s transient electrical parameters during turn-on and its application in online junction temperature measurement are studied.Firstly,in order to analyze the dynamic temperature sensitive characteristics of silicon carbide MOSFETs,the turn-on process was analyzed.An analytical model was established for the maximum change rate of the turn-on drain current,the maximum change rate of the turn-on drain source voltage,and the turn-on delay affected by temperature.A dynamic parameter temperature sensitive characteristic experimental platform was established,and the temperature sensitive characteristics of the transient electrical parameters of the switch were analyzed through experiments.By combining the analytical model,the relationship between the maximum rate of change in drain current,maximum rate of change in drain source voltage,and switch delay and junction temperature of silicon carbide MOSFET switches was revealed.Secondly,using the established analytical model of the relationship between dynamic temperature sensitive electrical parameters and temperature,the influence mechanism of bus voltage,driving resistance,driving positive voltage,and load current on the dynamic temperature sensitive electrical parameters of silicon carbide MOSFET was studied.A method to improve the temperature sensitivity of transient electrical parameters was proposed,and experimental verification was conducted through the dynamic parameter temperature sensitive characteristic experimental platform,I have mastered the influence of load current on the online measurement of junction temperature using dynamic temperature sensitive electrical parameter methodFinally,in order to achieve accurate online measurement of junction temperature and reduce the impact of load current on the accuracy of dynamic temperature sensitive electrical parameter measurement,a method combining multiple dynamic temperature sensitive parameters for junction temperature measurement was proposed,while extracting the value of load current.And a peak extraction circuit was designed to achieve online extraction of temperature sensitive electrical parameters.The effectiveness of the multi parameter fusion junction temperature measurement method and peak extraction circuit was verified through a DC chopper converter experimental platform.