McMurray full-bridge inverter – device count In a classic McMurray full-bridge inverter implementation, how many thyristors and diodes are typically used in the main power circuit?
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A4 thyristors and 2 diodes
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B4 thyristors and 4 diodes
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C8 thyristors and 4 diodes
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D8 thyristors and 8 diodes
Answer
Correct Answer: 8 thyristors and 4 diodes
Explanation
Introduction / Context:McMurray family inverters employ forced commutation networks. The full-bridge version duplicates the half-bridge commutation legs, increasing the device count to realize bidirectional load voltage with reliable commutation.
Given Data / Assumptions:
- Classic McMurray full-bridge (not McMurray-Bedford variant).
- Symmetrical commutation in both legs.
Concept / Approach:
A half-bridge McMurray stage uses a commutation pair per leg. Converting to a full bridge doubles the number of controlled devices while adding clamp/feedback diodes for energy recovery. A typical arrangement ends up with eight thyristors and four diodes in the main bridge paths, with auxiliary commutation components (capacitors, inductors) not counted here as “diodes”.
Step-by-Step Solution:
Half-bridge: 4 SCRs + 2 diodes.Full-bridge: two such legs → 8 SCRs + 4 diodes.Verification / Alternative check:
Reference topologies for McMurray full bridge show duplicated commutation legs yielding the cited device count.
Why Other Options Are Wrong:
- 4-device answers correspond to half-bridge or simpler bridges.
- 8 thyristors and 8 diodes overstates the diode count for the basic scheme.
Common Pitfalls:
Mixing McMurray and McMurray-Bedford counts or including auxiliary recovery diodes differently from main path diodes.
Final Answer:
8 thyristors and 4 diodes