GTO thyristor current regulator - with resonance circuit and active clamping using gate-turn-off clamping thyristor

摘要

The current regulator has a quasi-resonant DC intermediate circuit, the AC terminals of each phase coupled to a common connection of the paired transistors (T1...T6) connected across the DC terminals. The cathode of a gate-turn-off clamping thyristor (Tc) is coupled via a diode (Dc) to the junction between a resonance capacitor (Cr) and a resonance circuit thyristor (Ts) and to the cathode of the latter via a resistor (Rb2). An auxiliary capacitor (Cb) is coupled to the anode of a diode (Db1) coupled to the resonance circuit thyristor at its cathode, with a parallel resistor (Rb1) across this diode. A further diode (Db2) is coupled between the latter diode (Db1) and a clamp diode (Dc). ADVANTAGE - Reduced switching losses and increased switching frequency.