Page 76 - Rashid, Power Electronics Handbook

4 Gate Turn-Off Thyristors 61

The diode will be reverse biased because the gate voltage is 4.7 Applications
negative to the cathode. Therefore, the GTO will stop conduc-
tion. Gate turn-off thyristors have many applications, including
When the anode-to-cathode voltage is negative, that is, the motor drives, induction heating [4], distribution lines [5],
anode voltage is negative with respect to the cathode, the GTO pulsed power [6], and ¯exible ac transmission systems [7].
model will act like a reverse-biased diode. This is because the
p-n-p transistor will see a negative voltage at the emitter and
the n-p-n transistor will see a positive voltage at the emitter.
Therefore both transistors will be in the off state and hence the
GTO will not conduct. The SPICE subcircuit description of
the GTO model will be as follows:

.SUBCIRCUIT 1 2 3 ; GTO Subcircuit de®nition
*Terminal anode cathode gate
Q1 5 4 1 DMOD1 p-n-p ; p-n-p transistor with model DMOD1
Q3 7 6 1 DMOD1 p-n-p
Q2 4 5 2 DMOD2 n-p-n ; p-n-p transistor with model DMOD2
Q4 6 7 2 DMOD2 n-p-n
R1 7 5 10 O
R2 6 4 10 O
R3 3 7 10 O
.MODEL DMOD1 p-n-p ; Model statement for a p-n-p transistor
.MODEL DMOD2 n-p-n ; Model statement for an n-p-n transistor
.ENDS ; End of subcircuit de®nition

Acknowledgment Proceedings of Symposium on Power Electronics Electrical Drives.
The author would like to thank Mr Dinesh Chamund, Princi- Advanced Machine Power Quality. SPEEDAM Conference. Sorrento,
pal Engineer for Applications, Dynex Semiconductor, Italy; 3–5 June 1998, Vol. 1, pp. 2=5–10.
5. Malesani, L., and Tenti, P. Medium-frequency GTO inverter for
Doddington Road, Lincoln LN6 3LF, United Kingdom, who
induction heating applications, Second European Conference on
was invited to write this chapter and could not complete it due
Power Electronics and Applications: EPE. Proceedings, Grenoble,
to his work assignment France; 22–24 Sept. 1987, Vol. 1, pp. 271–276.
6. Souza, L. F. W., Watanabe, E. H., and Aredes, M. A. GTO controlled
References series capacitor for distribution lines, International Conference on Large
High Voltage Electric Systems. CIGRE'98, 1998.
1. Dynex Semiconductor: Data GTO data-sheets: web-site: http://
7. Chamund, D. J. Characterisation of 3.3 kV asymmetrical thyristor for
www.dynexsemi.com/products/proddata.htm
pulsed power application, IEEE Symposium Pulsed Power 2000 (Digest
2. Westcode Semiconductor: Data GTO data-sheets: web-site: http://
No. 00=053) pp. 35=1–4, London, UK, 3–4 May 2000.
www.westcode.com/ws-gto.html
8. Moore, P. and Ashmole, P. Flexible AC transmission systems: 4.
3. El-Amin, I. M. A GTO PSPICE model and its applications, The Fourth
Saudi Engineering Conference, November 1995, Vol. III, pp. 271–77. Advanced FACTS controllers, Power Engineering Journal 12:2, 95–
4. Busatto, G., Iannuzzo, F., and Fratelli, L. PSPICE model for GTOs, 100, 1998.