As we know, there are dozens of power semiconductor devices on the Chinese market, each with its own characteristics and application fields. However, in ultra-high-power applications, thyristor device can not be replaced by other power semiconductor device because of the excellent performance of high withstand voltage and small on-state voltage drop. Especially in high-power controllable rectifier equipment, high-voltage direct current transmission, locomotive traction, dynamic reactive power compensation and other applications, certain advantages and broad application prospects of thyristor are widely recognized. With the continuous increasing in power and capacity of converter equipment, especially the rapid development of HVDC transmission, the output power capacity of single thyristor is required to be greatly increased to reduce the applied number of thyristors in series and parallel connection in the device circuit. Such to reduce the volume of the device, make it smaller, lighter in weight, and lower in manufacturing cost, as well as beneficial to the current and voltage equalization between the bridge arms of the device, thereby greatly improving the reliability of the device operation. The economic benefit was obtained utmost. Therefore, since the establishment, Runau company has always taken the R&D and production of large-capacity, high-power, and high-voltage thyristor as the main direction and top mission of the company’s development strategy. In recent years, gratifying technological progress through endless efforts had achieved, and continuous successes were obtained.