Title :
A large-capacity GTO inverter with low-loss snubber circuits
Author :
Kawakami, N. ; Ueda, S. ; Hombu, M. ; Ueda, A. ; Jifuku, Y.
Author_Institution :
Hitachi Ltd., Ibaraki, Japan
Abstract :
A large-capacity inverter using high-power gate turn-off (GTO) thyristors that can be used instead of a cycloconverter in AC drives is presented. With the techniques of multiple configuration and GTO series connection, the inverter capacity is increased effectively. High conversion efficiency is obtained by using low-loss snubber circuits for GTOs. It is confirmed that the low-loss snubber circuits using energy recovery units (ERUs) have good performance in pulse-width modulated (PWM) operation. High-energy recovery efficiency is obtained, especially in leading operation (turn-on operation when freewheeling diodes conduct). These snubber circuits have superior ability for clamping overvoltage at GTO turn-off. A 2750 kVA inverter with low-loss snubber circuits using high-power GTOs has been fabricated and evaluated
Keywords :
invertors; overvoltage protection; pulse width modulation; thyristor applications; 2750 kVA; AC drives; GTO series connection; GTO turn-off; PWM; energy recovery units; high conversion efficiency; large-capacity GTO inverter; low-loss snubber circuits; multiple configuration; overvoltage clamping; pulse-width modulated operation; turn-on operation; Circuits; Induction motors; Power supplies; Power system harmonics; Pulse width modulation inverters; Reactive power; Rectifiers; Snubbers; Switching frequency; Thyristors;
Journal_Title :
Industry Applications, IEEE Transactions on
