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Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
Like a thyristor, the GCT has a low on-state voltage of about 2 volts at 4000 amps. To reduce the turnoff losses, the device current must be turned off in 1 microsecond. Since the voltage applied to the gate is only 20 volts or so, the circuit inductance must be extremely low. For example, to turn off a current of 3000 amps in 1 microsecond, with 20 volts, requires that the inductance in the circuit must be less than about 6nH. Achieving such a low gate circuit inductance requires special design considerations. For this reason, many GCTs are sold integrated with a gate circuit. The integrated unit is thus called an integrated gate commutated thyristor (IGCT). Figure 120.19 shows a picture of an IGCT package, which includes the GCT, freewheeling diode, and gate driver. The input circuit merely requires a 20 -volt power supply and an infrared fiber optic link to deliver the turn-on and turn-off commands.
Principles of Energy Conversion
Published in Hamid A. Toliyat, Gerald B. Kliman, Handbook of Electric Motors, 2018
Hamid A. Toliyat, Gerald B. Kliman
The IGCT evolved from the GTO thyristor by realizing that if the entire anode current was extracted from the gate, the cathode current would be reduced to zero and the device would turn off as a PNP transistor. This can be seen by referring to Fig. 9.81(a). If a gate current equal to the anode current is extracted from the gate terminal, the cathode is essentially open (the gate cathode junction is reversed biased), and the PNP transistor portion of the device is left to turn off the anode current and block voltage. There is now no dv/dt effect and the device can be operated without a snubber circuit. The IGCT has been optimized for this type of operation [59]. Due to the large reverse gate current, the IGCT switches faster than the GTO. Since most applications require an inverse parallel diode, IGCT devices have been implemented with an integral inverse diode fabricated on the same silicon. This leads to the often used symbol of Fig. 9.81(b) where the little reverse triangle represents the inverse parallel diode.
Power Electronics
Published in Timothy L. Skvarenina, The Power Electronics Handbook, 2018
Kaushik Rajashekara, Sohail Anwar, Vrej Barkhordarian, Alex Q. Huang
To compare these various semiconductor technologies, two IGBTs, an IGCT, a GCT, and three ETOs were used [1]. One IGBT and the GCT are made by Mitsubishi, and the ETOs have been developed by researchers at Virginia Tech. The other IGBT is made by EUPEC, and the IGCT is from ABB. The IGBTs, CM1200HA-66H and FZ1200R33KF2, are rated for 1200 A (DC) and 3300 V, and are packaged in plastic modules 14 by 19 cm in size. The IGCT and the GCT are both 4500-V devices, which are rated for 4000 A maximum controllable current. The first ETO used, ETO4060s, is rated for 6000 V and 4000 A controllable current, and is based on a Toshiba GTO. The IGCT, the GCT, and the ETO4060s are packaged in 93-mm press-packs and, with gate drivers, have a maximum width of around 20 cm. The second ETO used, ETO1045s, is a small (53-mm) device rated for 4500 V and 1000 A. This ETO is based on a Westcode GTO. The ETO1045s is obviously of a lower rating than the GCT and IGCT, but it uses a fast conventional GTO, whereas the ETO4060s is based on a GTO designed for about 300 Hz. One final device used is a newly designed ETO, the ETO4045A, which is based on an ABB GTO similar to the thyristor used in the IGCT. The average current ratings for the IGCT, GCT, ETO4045A, and ETO4060s are 1200 A, whereas the ETO 1045 is suitable for about 450 A average. When the switching losses of the IGBT and a safe
Novel discontinuous PWM for dc-link voltage balancing of multilevel quasi-nested topologies
Published in International Journal of Electronics, 2022
The advancement in gate-controlled, power semiconductors like the insulated gate bipolar transistor (IGBT), the gate turn-off thyristor (GTO) and the gate-commutated thyristor (IGCT) has given great impulse to the development of medium and high voltage topologies within power ratings. In order to reach these power ratings, using traditional converter topologies (mainly NPC and two-level voltage and current source converters), the semiconductor technology has made great improvements to reach higher nominal blocking voltages and currents, currently at 8 kV and 6 kA) (Adler et al., 1984; Baliga, 1988; Moguilnaia et al., 2005), which also increased the final costs.