Gate control system of the inverter using gate-turn-off thyristors

A gate control system of the inverter for generating AC output of a predetermined frequency and having plural GTO thyristors connected in a predetermined manner comprising:

• a means for generating a first pulse signal on which the frequency of the AC output is based;
• a means for generating a second pulse signal delayed for a predetermined period of time from the first pulse signal;
• a phase reference signal generating means for generating responsive to the second pulse signal a reference signal corresponding to the phase of the AC output of the inverter;
• an ON pulse generating means synchronizing with the second pulse and the phase reference signal to generate ON pulses corresponding to the GTO thyristors, respectively;
• an OFF pulse generating means synchronizing with the first pulse and the phase reference signal to generate OFF pulses after the ON pulses;
• a negative bias signal generating means for generating negative bias signals after the OFF pulses;
• an operation stop means synchronizing with the first pulse to supply the OFF pulses and then the negative bias signals to the GTO thyristors at the time when the operation of the inverter is to be stopped;
• and
• a commutation failure protecting means for supplying the ON pulses to the GTO thyristors at the time of commutation failure.