Design Of Gate Driver Circuit For Si-IGBT+SiC-SBD Hybrid Module

Silicon carbide devices are gradually replacing traditional silicon devices in power electronics applications due to their higher operating temperature range,lower on resistance and lower switching losses.The new generation of"Si-IGBT+SiC-SBD" hybrid module achieves the optimal tradeoff between the performance and the cost of the device,but the traditional gate drive technology can not solve the problem of the long time current oscillation in the process of opening.Therefore,it is necessary to design a gate driver circuit which can suppress the current oscillation of the hybrid module.In this thesis,the switching characteristics of the hybrid module are analyzed in detail.The two parts are divided into silicon based IGBT and silicon carbide diode,and it is found that the reverse recovery of the freewheeling diode is the root cause of the current oscillation.Compared with the conventional silicon based diode,the silicon carbide diode has a large depletion layer capacitance and a small series resistance,so that the current oscillation exhibits the characteristics of low attenuation and low damping.The output driver circuit proposed in this thesis realizes the estimation of the time that the current oscillation raises by detecting the dVGE/dt and d(diC/dt)/dt.And by reducing the IGBT drive current to increase the resistance of the IGBT,the decay resistance of the oscillation circuit will be increased and the decay rate of oscillation will be speed up.And also,this circuit effectively suppress the current oscillation without sacrificing the current overshoot and opening loss by controlling the IGBT collector voltage dvC/dt and current gradient diC/dt.The proposed circuit has been implemented in 0.5?m 600V SOI BCD technology.The test results show that,compared with the traditional gate driver circuit,the circuit designed in this paper can effectively suppress the current oscillation of the hybrid module when it is turned on,and the oscillation time is only 38.7%of the traditional drive circuit.At the same time,the circuit also has obvious effect on the current overshoot and the opening loss.Compared with the traditional driving circuit,the circuit is reduced the current overshoot and the opening loss by 33.4%and 21.3%respectively.It can be said that the circuit achieves the desired design goals.