An 8.5kV Sacrificial Bypass Thyristor with Unprecedented Rupture Resilience

The paper details the development of a device intended for use as a sacrificial cell bypass switch in cascaded multi-level topologies with serial redundancy of cells of up to 4.6 kV (DC). The design is based on an 8.5 kV phase-control thyristor for industrial use. Maintaining rupture resilience constituted the main challenge. It ultimately triggered surges of more than 210 MA2s without rupturing. Secondary challenges include a guaranteed surge incapability and ensuring a long-term stable short-circuit failure mode.