Transient Thermal Management of Press-Pack Thyristors Using Stacked Structure and Phase Change Material

Thyristor crowbar circuits are a critical component in Static Synchronous Series Compensator (SSSC) protection systems, and lower-capacity thyristors are often selected to minimize costs. However, their thermal capacity is limited and the heat generated by the overcurrent will cause the junction temperature to rise above the limit, leading to thermal breakdown of the device. A thyristor with a lower breakdown voltage reduces power consumption for the same current flow, resulting in less heat generation, and the integration of phase change material (PCM) into the package of a power device can use latent heat to absorb large amounts of heat to suppress junction temperature rise. This paper proposes a stacked structure that provides more space for the PCM, and the thermal effects of the stacked structure and the integrated PCM structure are analyzed separately by finite element analysis (FEA). The simulation shows that the stacked structure can reduce the junction temperature at a power pulse of 16kW, and the junction temperature is further reduced by the additional heat absorbed by the PCM. The proposed package structure improves the short-term overcurrent capability of the press-pack thyristor.