In single-phase DC drives, a 'dual converter' is used for reversible operation. Which connection accurately describes a single-phase dual converter?

Introduction / Context:
Dual converters provide four-quadrant DC drive capability by allowing power flow and motor current reversal without mechanical contactors. Understanding their connection is essential for regenerative braking and smooth reversals.

Given Data / Assumptions:

• Single-phase system.
• Reversible voltage polarity at the DC output is required.

Concept / Approach:
A single-phase dual converter comprises two fully controlled bridges connected in antiparallel on the DC side. One bridge provides positive polarity DC, the other provides negative polarity DC. Interlocking and circulating/non-circulating modes manage current reversal and harmonics.

Step-by-Step Solution:
1) Identify need: reversible DC output polarity.2) Use two controlled bridges; one is assigned positive polarity, the other negative.3) Connect antiparallel so only one bridge conducts at a time (or both in circulating mode with reactors).
Verification / Alternative check:
Drive manuals depict antiparallel fully controlled bridges; semiconverters are not used for full four-quadrant operation.
Why Other Options Are Wrong:

• Parallel same polarity cannot reverse output.
• Semiconverters do not provide full four-quadrant functionality.
• Center-tapped single bridge does not enable polarity reversal without additional hardware.

Common Pitfalls:

• Confusing antiparallel with anti-series; polarity reversal requires antiparallel arrangement.
• Ignoring circulating current management between bridges.

Final Answer:
Two fully controlled converters in antiparallel.