Design and Verification of Miniaturized High-Power Pulsed Laser Trigger System for Optically Controlled Multigate Thyristors

Abstract

Optically controlled multigate thyristors (OCMGTs) face challenges in high-voltage series applications, specifically requiring high-power triggering and synchronous turn-on of multiple gates. To address these issues, this article proposes a compact, high-power nanosecond pulse laser trigger system based on the field-induced nonlinear trigger mode (Mode C), targeting a benchmark of 4.5-kW peak optical power. The drive circuit utilizes a SiC MOSFET capacitor-direct-drive topology with a compact, low-inductance package, achieving a peak current of 146.6 A and an 80 ns rise time. Furthermore, the optical system employs a passive arrayed fiber combining and homogenization method alongside a transmissive-reflective beam-splitting mechanism, keeping the energy deviation among the three sampled optical paths within ±5%, which serves as a representative indication of the seven-spot uniformity. Experiments on a 42-kV high-voltage series assembly validate the design, achieving synchronous turn-on with a peak current of 20.15 kA, a di/dt of 19.89 kA/ $\mu $ s, and a measured interstage absolute delay of 413–436-ns relative to the master trigger (channel-to-channel skew $\approx$ 23 ns). Consequently, no turn-on delay or local overvoltage occurs across any stage, establishing a highly reliable engineering path for all-solid-state pulsed-power systems.