| In recent years,wide-bandgap power semiconductor devices represented by silicon carbide(SiC)MOSFET have been gradually applied in the field of high frequency,high temperature and high power by their excellent performance.The halfbridge structure is the most common topology structure in the above applications.However,its crosstalk issue limits the switching speed and efficiency of the SiC MOSFETs.In order to suppress the crosstalk issue,the control of external circuit parameters is a direct and effective method.In this paper,the parameters influence and control of the crosstalk issue in the half-bridge structure of SiC MOSFETs are studied systematically.Firstly,the mechanism and process of half-bridge crosstalk issue of SiC MOSFET under resistive load and inductive load were compared and analyzed.Moreover,the crosstalk voltage analytical models of SiC MOSFET under resistive load and inductive load were established respectively.A circuit equivalent method was proposed for the modeling under resistive load,which realizes voltage decoupling between upper and lower bridge arm devices.For the inductive load,a complete analytical model with input parameters of only the device parameters and the external circuit parameters was established.To verify the effectiveness of the models,an experimental platform for half-bridge crosstalk characteristics of SiC MOSFET was built.Secondly,the influence and regulation of the external circuit parameters on the crosstalk voltage of SiC MOSFET under different loads were studied through the established crosstalk voltage analytical models.Moreover,the results were verified by the half-bridge crosstalk characteristic experiment platform of SiC MOSFET.It includes the influence and regulation of the external gate resistance of the upper bridge arm and the lower bridge arm simultaneously changing on the crosstalk voltage under inductive load under different common source inductance,the influence and regulation of the external gate resistance and the common source inductance of the lower bridge on the crosstalk voltage under different loads.Finally,in order to evaluate the influence of bias temperature instability(BTI)on the half-bridge crosstalk issue of SiC MOSFET and optimize the control of external circuit parameters,the BTI experiment platform of silicon carbide MOSFET was built.Moreover,the positive bias temperature instability(PBTI)and negative bias temperature instability(NBTI)experiments were carried out.The experimental results show that the NBTI will lead to the reduction of the control range of the external circuit parameters to suppress crosstalk.Therefore,the influence of NBTI should be considered in advance when designing parameters to suppress crosstalk.It means that the external circuit parameters should be designed according to the threshold voltage and the peak value of crosstalk voltage after the influence of NBTI. |
