The forward breakover voltage and forward conduction voltage drop of a thyristor have been measured as a function of decreasing temperature between 25 degrees C and -180 degrees C. These data are presented for a 1200-V, 560-A average, inverter thyristor. Both the measured and calculated forward breakover voltages exhibit negative temperature coefficients. The decrease in V/sub BF/ at low temperatures necessitates that thyristors with overrated blocking voltages be used at these temperatures.< >
Power semiconductor devices are key components of power electronics circuits and equipment and are used primarily as switches or rectifiers. The main function of power semiconductor devices in power electronics applications is to control and transfer the flow of electrical energy from one form to another and in a form suitable for the user. In this manner, power semiconductor devices act as switches, having two operating modes: on (conducting) and off (nonconducting). While these two states are important in determining the efficiency and applicability of a semiconductor device, the transitions between them significantly impact system performance, determine energy losses, and affect reliability and other associated aspects of performance.
Triggering measurements were performed on thyristors with different gate geometries at various combinations of peak gate current, gate pulsewidth, and gate di/dt, to determine the trigger dependence of pulsed anode current di/dt. Peak gate current was varied from 4 A to 12 A, gate pulse width from 250 ns to 8 μs, and leading edge di/dt from 23 A/μs to 320 A/μs. Only the peak gate current was found to affect pulsed anode current di/dt.
The switching characteristics of 4H-SiC asymmetric GTO thyristors are studied and compared to Si-based IGBTs, MCTs and MOSFETs. Forward current density, turn-off time and forward blocking voltage parameters are matched for the various switching devices. From the measurements, the necessary parameters were extracted to develop a simple PSPICE circuit model for the SiC GTO. The simulated response of the model is compared to the experimental response of the device.
Although insulated-gate bipolar-transistor (IGBT) turn-on losses can be comparable to turn-off losses, IGBT turn-on has not been as thoroughly studied in the literature. In the present work IGBT turn on under resistive and inductive load conditions is studied in detail through experiments, finite element simulations, and circuit simulations using physics-based semiconductor models. Under resistive load conditions, it is critical to accurately model the conductivity-modulation phenomenon. Under clamped inductive load conditions at turn-on there is strong interaction between the IGBT and the freewheeling diode undergoing reverse recovery. Physics-based IGBT and diode models are used that have been proved accurate in the simulation of IGBT turn-off.
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