Abstract : This paper introduces the development of Insulated Gate Bipolar Transistors (IGBTs), and outlines the structure and performance characteristics of high-power IGBT transistors, as well as the structure, operating characteristics, and applications of frequency converters composed of high-power, high-voltage IGBT transistors in urban transportation and railway transportation. Keywords : Locomotive, EMU, AC drive, semiconductor device, control technology, new materials, new processes, prerequisites and factors for the success of IGBT technology. The development of IGBT frequency converter technology in locomotive and rolling stock traction systems began in the early 1990s, when it was used in the low-power range. In Europe, the first IGBT transistor frequency converter was designed and manufactured by Siemens in 1992 and used in low-floor trams in Frankfurt. The application range of IGBT transistor traction frequency converters has been expanded because of the improved turn-off capability and the increased current carrying capacity. Over the past 10 years, it has been continuously improved due to many major technical decisions made regarding transistor structure and manufacturing processes. For designers, the most important issues are the mechanical arrangement of semiconductor devices (IGBT transistors, diodes) within the housing and the high demands placed on the traction system due to load cycle variations. To solve this problem, careful research and experimentation were required. This resulted in the development of a high-strength housing for the frequency converter module, capable even of withstanding the particularly harsh operating conditions of subways, where the total number of operating cycles throughout the line's lifespan is very high. IGBT transistor traction frequency converters have two advantageous characteristics that are important not only for railways but also for manufacturers. First, these devices offer potential for cost reduction due to their low assembly cost and improved traction system efficiency. The second characteristic enabling the rapid adoption of IGBT transistor frequency converter technology is the high reliability and versatility of the traction system. Even in the early stages of frequency converters using gate turn-off thyristors (GTOs), it was evident that the complexity of these devices limited further improvements in reliability. In particular, the control circuitry of the GTO thyristor has a very strong impact on system reliability. [b][align=center]For more details, please click: Development of IGBT Transistor Traction Frequency Converters[/align][/b]