Study of driving characteristics of laser diodes used for triggering light-triggered thyristors (LTT)

The high-power thyristors are the core component of the HVDC systems. Traditional thyristors are triggered by the electric current pulses, as the development of the laser technology; light-triggered thyristors (LTT) are used more widely in the HVDC field due to its low triggering power and strong resistance against electromagnetic interferences. In connection with the current situation that the researches of driving mode optimization of the LTT and the driving characteristics of laser diodes in concert with LTT are shortage, a series of experiments about the light output characteristics of laser diodes and the light pulse absorbing and opening of LTT were designed in this paper, and the following conclusions were got after the results analyses: the output of laser diodes has an important relationship with the wavelength of the light, the I/O characteristic curve has three areas like the V-A curve of diodes; the opening time of LTT is shorter when it achieves a steep and high-amplitude pulse from the laser diode.