Research On IGCT Circuit Model And Key Techniques Of Driver Circuit

Integrated gate commutated thyristor(IGCT)is a new type of high-power semiconductor device,which integrates gate commutator thyristor(GCT)and gate driver through printed circuit board(PCB)in a low inductance way,and has a good application prospect.It is necessary to turn on and turn off the GCT by means of the integrated gate hard drive circuit.The advantages and disadvantages of the driving circuit directly affect the realization of the excellent characteristics of the device,so it is necessary to strictly control the stray inductance in the circuit.And,the circuit simulation model of IGCT is lacking in the design of driving circuit and application system.Aiming at the above problems,the key technologies of IGCT circuit model and drive circuit of 4500V/4000A IGCT are studied and discussed in this paper,the main contents are as follows:Firstly,the switch principle and internal commutation mechanism of IGCT are studied,and the hard-drive circuit simulation model(M-2T-3R-C)of IGCT is established.This model can accurately characterize the switching characteristics and internal commutation mechanism of GCT,which can replace the GCT device in the simulation.The key parameters of the model are analyzed and modified to verify the accuracy of the model.On this basis,the circuit simulation model of Dual-GCT is established the simulation waveform are compared with the experimental waveform under the same conditions,and the accuracy of the model is verified.Continue to extract the parameters of the circuit model based on SiC power MOSFET.The simulation results show that the switching speed of the circuit model based on SiC power MOSFET is 3?s higher than that of ordinary MOSFET.This model has laid a foundation for broadening IGCT and its derived devices.Secondly,the turn-off circuit of 4500V/4000A IGCT has a higher requirement for hard drive.When it is turned off,the amplitude of gate current should be up to 4000A within 1?s,and its rising rate should reach above-4000A/?ps.The stray inductance must be controlled in 5nH.In order to control the stray inductance of the turn-off circuit,the optimal value of the clamp capacitance and the clamp resistance is extracted from the optimal analysis of the turn-off clamp circuit.Then to study the distribution of stray inductance in turn-off circuit,the extraction method of the stray inductance and the effective measures to reduce the stray inductance are proposed.The total stray inductance of the turn-off circuit is reduced from 13.6nH to 4.7nH,and finally to 3.5nH.The gate current peak and rising rates are-6120A and-5720A/?s,which can meet the requirement of the turn-off ability of the drive circuit of 4500V/4000A IGCT.Thirdly,according to the index of the hard drive circuit,the working principle of the main driver circuits of turn-on,on-state and turn-off is studied,and a complete circuit schematic diagram is proposed for the key problems to be solved.Based on the simulation model of the GCT hard drive circuit established in this paper,the circuit simulation is carried out.The second trigger is studied in depth to ensure the complete opening of all units in the GCT turn-on process and avoid the false turn-off of GCT in the on-state.The logic control and detection module of IGCT driver circuit are studied,and the 4500V/4000A IGCT driver circuit is designed.Lastly,the 4500V/4000A IGCT driver circuit PCB is designed and made.The experimental circuit is built to verify the gate current,anode voltage and monitoring circuit of the main drive circuit.The experimental verification of the whole circuit is carried out by using the IGCT test bench and the double pulse test method.The reliable drive of 4500V/4000A IGCT is realized,and in terms of volume,turn-on delay time,turn-off delay time,it is better than the drive board of the same grade IGCT products of ABB.