Single-phase full-wave converter (M-2, center-tap): peak inverse voltage (PIV) A single-phase full-wave converter (M-2 connection) uses a center-tapped secondary. The RMS voltage across each half of the secondary is 300 V. What is the PIV rating required for each thyristor?

Introduction / Context:
In a center-tapped, single-phase full-wave converter (M-2), the non-conducting thyristor must withstand the inverse voltage when the other device conducts. Correctly estimating the peak inverse voltage (PIV) is essential for device selection and reliability.

Given Data / Assumptions:

• Center-tapped transformer with each half secondary RMS = 300 V.
• Ideal transformer and devices, no commutation overlap.
• PIV for each thyristor in a center-tap full-wave configuration equals twice the peak of the half-secondary.

Concept / Approach:
For a center-tapped secondary, the peak of each half is V_m,half = Vrms,half * sqrt(2). When one thyristor conducts, the other sees the sum of the instantaneous voltages of both halves, reaching approximately 2 * V_m,half as the peak inverse voltage.

Step-by-Step Solution:
Compute peak of half secondary: V_m,half = 300 * sqrt(2) ≈ 424.3 V.PIV per thyristor = 2 * V_m,half ≈ 2 * 424.3 ≈ 848.6 V.Round to a practical rating ≈ 850 V; designers typically choose the next standard device rating (e.g., 1,000 V) with margin.

Verification / Alternative check:
Well-known result: for center-tap full-wave rectifiers (diodes or SCRs), PIV ≈ 2 * V_m,half.

Why Other Options Are Wrong:

• 300 V or 600 V: use RMS values or a single peak; both undervalue the true PIV.
• 1,200 V: overly conservative for the stated RMS value (though may be chosen for margin).
• 600^2 V: meaningless.

Common Pitfalls:

• Mistaking total secondary RMS for half-winding RMS in PIV calculations.
• Confusing RMS with peak quantities.

Final Answer:
850 V (approximately)