Hybrid series connection of a controllable switch and thyristors

A hybrid series connection of a controllable switch such as a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), or a gate-turn-off thyristor (GTO) and thyristors is proposed and studied. The proposed hybrid series connection has a controllable turn-off capability. The thyristors in the proposed connection are not turned off by auxiliary commutation circuits, but turned off by the series-connected controllable switch, so that burdensome auxiliary commutation circuits are saved. A hybrid series connection of a BJT (or an IGBT) and GTOs is also studied. The proposed hybrid series connection can be applicable to DC choppers, inverters, and zero-voltage-switching resonant converters in high-voltage and high-power applications.