High-Voltage Si IGBT/SiC MOSFET Series-Connected Hybrid Switch

Hybrid switches combining shunt silicon (Si) insulated-gate bipolar transistors (IGBTs) and silicon carbide (SiC) metal-oxide semiconductor field-effect transistors (MOSFET) offer advantages of low losses, cost-effectiveness, and fast switching speed. Nevertheless, the restricted hybrid switching voltage level hinders the wide application of this emerging switch combination in pulse power applications. Serially connecting switches proves effective in augmenting the switching blocking voltage; however, there has been insufficient research conducted on series of hybrid switches. A comparative analysis is conducted between the single-column structure and the two-column structure of hybrid switches in this article. Both structures exhibit excellent switching speed, but the single-column structure demonstrates notable advantages in terms of switching losses. On the basis of the above series structure, it is analyzed that the high-voltage series hybrid switch often works under large-current conditions. A gate control strategy of series-connected hybrid switch taking into account switching speed, switching losses, and waveform distortion rate is proposed. An 18-stage series-connected hybrid high-voltage switch was built to validate its equalization characteristics and output capabilities. It finally realizes the blocking voltage of 15 kV at 185- $\Omega$ load resistance, the switching turn-on time (the 90%–10% voltage fall time) of 64.3 ns, the pulsewidth of 2–50 $\mu$ s adjustable, and the repetition frequency of 1 kHz.