Reliability and availability (Part 4: IGCT based converters)
IGCT is a power semiconductor used in medium voltage converter applications. The abbreviation stands for Integrated gate-commutated thyristor. Unlike classical thyristor that can only be switched on, IGCT can be switched on and off through its adjacent gate unit. Therefore, it is a self-commutated device. IGCT has very low losses and allows highly efficient power conversion. For more information you can read here: https://new.abb.com/semiconductors/integrated-gate-commutated-thyristors-(igct)
IGCT is inherently a very robust device. Same as normal thyristor, it can withstand high surge current for a short time. IGCT based converters therefore normally have fuseless design. The best thing regarding IGCT is that the semiconductor itself practically does not age. The gate unit ages, but not faster than any other electronics.
Variable speed drives based on IGCT are being manufactured since mid 1990s. Their installed base is estimated to more than 10’000 units worldwide. The operational experience exceeds 20 years. No surprise, these products are very mature and field proven. Majority of these products are still in active phase and this will hardly change in upcoming years.
Main drive manufacturers report IGCT based drives as very reliable:
https://library.e.abb.com/public/871a18f5be50461b83cfceae9f021978/67-71%204m6009_EN_72dpi.pdf
https://library.e.abb.com/public/4e960207fbc5045885257b63006788c9/MVD-PHPF01U-EN-REVE.pdf
Due to low parts count n+1 redundancy is not needed. IGCT based drives serve in the roughest applications such as rolling mill drives in metals, ball and SAG mill drives in mining or drives in marine propulsion. Moreover, IGCT based converters can be found in power conversion applications such as grid interties (e.g. railway interties in Switzerland, Germany, Austria or Scandinavian countries), offshore wind turbines, hydro power plants etc.
References
[1] ABB Semiconductors, https://new.abb.com/semiconductors
