ABB industrial control module 5SHY3545L0021 thyristor module controller IGCT

BCT Application in Drives Equipment

Regenerative DC Drive

Overview:

• The speed control of electrical motors is commonly achieved using AC or DC drives.
• BCT’s main application areas in drives equipment are in DC drives and feeding sections for AC drives with energy regeneration during braking.
• Another application area is in cycloconverters for large synchronous motors.
• The chosen application example is a regenerative DC drive.

Regenerative DC Drive:

• The standard solution involves a (B6C)2 connection, requiring 12 thyristors arranged in two fully controlled rectifiers in an anti-parallel connection (shown in figure 4.3).
• When BCTs are used, a (B6C)2 bridge is built with only 6 semiconductor components.
• Depending on the solution, the (B6C)2 bridge may have reduced height or width.
• The use of BCTs enables a more compact solution, reducing the need for mechanical components like heat sinks and supports.
• Footprint reduction for larger systems, e.g., rolling mill line-ups, is about 10-30%, leading to significant cost savings.
• Compact solutions allow for locating high-power drives equipment in rooms with reduced height, avoiding paralleling low-power bridges when more power is needed (e.g., in harbor cranes).

Soft Starter for Asynchronous Machines

Overview:

• When starting an asynchronous machine directly fed from a three-phase supply net, high starting currents stress the machine and feeding circuit.
• Soft starters, consisting of pairs of anti-parallel thyristors (one pair per phase), are used to reduce starting stresses.
• BCTs can directly replace these anti-parallel thyristors in the soft starter.

Advantages of BCT in Soft Starters:

• Substituting anti-parallel thyristors with BCTs leads to a reduced number of mechanical parts like mounting clamps.
• Enables a more compact solution for soft starters.

Both applications showcase how BCTs can enhance system efficiency, reduce mechanical parts, and enable more compact solutions in drives equipment, leading to cost savings and improved performance.