Establishment And Verification GCT Circuit Simulation Model

Intergrated Gate Commutated Thyristor (IGCT) is a new high power semicondoctor device based on the Gate Turn-off Thyristor (GTO) and has a very good application prospect in the high-voltage power field. In order to broaden the application scope of IGCT, it is necessary to establish a simulated circuit model which can accurately express its switching characteristics.In this paper, based on the structural characteristics and operation principle of GCT, a M-2T-3R equivalent circuit model of GCT was presented. As an example for 4.5kV/4kA asymmetric IGCT, the switching characteristics of GCT were studied by Cadence-Pspice simulation software. The influence of model parameters and gate parasitic inductance on the switching characteristics of the GCT was analyzed, and the accuracy and suitability of the GCT simulated circuit model were verified by comparing with the numerical results. The main research contents are as follows:Firstly, the structure features and operating principle of GCT are briefly introduced. Based on the internal commutation process and double transistor model, a MOSFET is introduced between GCT gate and cathode, and proposed a M-2T-3R equivalent circuit model of GCT unit.Secondly, based on the GCT structural features with the multiple gate-cathode in parallel, the number of GCT cathode rings is equivalent to the number of parallel units, and the M-2T-3R circuit simulation model of GCT is established. The key model parameters, such as, the current amplification coefficients, transit times, bias capacitances of the PNP and NPN transistors, static resistance and internal distribution inductance of GCT, are extracted to analyze the influence of the key model parameters on the GCT switching characteristics.Thirdly, the accuracy and suitability of M-2T-3R circuit simulation model of GCT are analyzed. by circuit simulation. The M-2T-3R model circuit simulation result of the switching characteristic for 4.5kV/4kA IGCT is compared with device numerical simulation results, the(?)measured waveforms and the application manuals, the key characteristic parameters can basically fulfill the index requirements, this shows that the model can accurately express the commutation process and the switching characteristics of GCT. And the circuit simulation model is used in the 4.5kV/3.6kA and 4.5kV/2.2kA series IGCT respectively, and the switching characteristic curves are basically consistent with the numerical simulation results, and it shows that the model is suitable for IGCT with different current levels.The prosented GCT circuit simulation model can be used in the design of IGCT driver and protection circuit and the simulation of IGCT application system.