Inverter-Fed AC Drive Systems for Steel Rolling Mills

Masahiro Tobise, Omika Works, Hitachi, Ltd.
Ken'ichi Onda, D. Eng., Power & Industrial Systems R & D Division, Hitachi, Ltd.
Shigeru Sugiyama, Omika Works, Hitachi, Ltd.
Mitsunori Yamashina, Hitachi Works, Hitachi, Ltd.


In the steel rolling industry, steel rolling plants with inverter-fed drive systems have been applied for small to large-capacity motors. The power devices supporting the inverter drive continue to gain in capacity, as represented by the 6 kV, 6 kA gate turn-off thyristor (GTO). The large capacity of these elements makes it possible to reduce the size of medium- and large-capacity inverter drive systems.

The application range affected by power line needs has also expanded accordingly. To satisfy these needs, Hitachi, Ltd. provides a large-capacity GTO inverter drive system for steel rolling mills. A large-capacity GTO inverter drive system (motor capacity: 5000-6400 kW class) using the latest large-capacity GTO (6 kV, 6 kA) was developed along with a medium-capacity insulated gate bipolar transistor (IGBT) inverter drive system (motor capacity: about 2000 kW) using a large-capacity IGBT. These drive systems satisfy power line needs with high power factor and minimum harmonics.

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