Peak thyristor current: midpoint (M-2) vs. full bridge for same RLE load current A single-phase full-wave converter in midpoint (M-2) connection feeding an RLE load has a peak thyristor current of 15 A. For a fully controlled full-bridge converter feeding the same load current profile, the peak current through each thyristor will be:

Introduction / Context:
Converter topologies (midpoint M-2 versus full bridge) change transformer utilization and device RMS currents, but the instantaneous device current waveforms relative to the load are similar: when a device conducts, it carries the load current. Comparing peak device currents helps with device selection and thermal design.

Given Data / Assumptions:

• M-2 midpoint converter: peak thyristor current = 15 A.
• Same RLE load current is assumed when comparing to a fully controlled full-bridge.
• Ideal components, same output current waveform envelope.

Concept / Approach:

In both M-2 and full-bridge configurations, an individual device that is conducting carries the instantaneous load current. While RMS currents and transformer secondary currents differ between the two topologies, the peak device current equals the peak load current when the device conducts. Thus, for the same load current profile, the peak thyristor current per device does not change.

Step-by-Step Solution:

Verification / Alternative check:

Waveform sketches of both circuits show rectangular or quasi-rectangular device current pulses equal to load current magnitude; RMS differs due to conduction pattern and transformer split in M-2.

Why Other Options Are Wrong:

30 A (a) doubles incorrectly; 15√2 A (b) confuses peak with RMS; 7.5 A (d) halves incorrectly; 10 A (e) is arbitrary.

Common Pitfalls:

Confusing RMS ratings and transformer secondary currents with peak instantaneous device current requirements.

Final Answer:

15 A