Single-phase converter with center-tapped transformer and highly inductive load For a single-phase full converter using a center-tapped secondary and a highly inductive (continuous current) load, with firing angle α, each thyristor conducts for what electrical angle?

Introduction / Context:
Full-controlled single-phase converters commonly use either a bridge or a center-tapped secondary with two thyristors. With a highly inductive load, current is continuous and each device conducts for a fixed span independent of the firing angle, apart from overlap. The question targets recognition of conduction intervals under continuous current.

Given Data / Assumptions:

• Single-phase full control with center-tapped transformer secondary.
• Load inductance is large enough to maintain continuous current.
• Overlap and source impedance are neglected for simplicity.

Concept / Approach:

In continuous conduction, once fired, a thyristor continues to conduct until current is naturally transferred to the other device. In the ideal case, each device conducts for 180 degrees (π radians). Firing angle α shifts the current transfer instant but does not reduce the total conduction angle per device for a continuous current scenario.

Step-by-Step Solution:

Verification / Alternative check:

Waveforms in standard texts show rectangular device current pulses of width π when load inductance is high.

Why Other Options Are Wrong:

α or π − α would apply if current were discontinuous; π/2 is for special commutation intervals; 2π − α is not meaningful for single device conduction in one cycle.

Common Pitfalls:

Assuming conduction width shrinks with larger α even under continuous current; forgetting that inductance sustains current.

Final Answer:

π