Single-phase step-up cycloconverter: 50 Hz to 100 Hz A single-phase step-up cycloconverter converts 50 Hz input to 100 Hz output. One half-wave of the 50 Hz input will produce how many output waves?
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AOne half wave of output
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BOne full wave of output
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CTwo full waves of output
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DEither one or two full waves depending on control
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ENo output in that interval
Answer
Correct Answer: One full wave of output
Explanation
Introduction / Context:Cycloconverters synthesize a new frequency directly from an AC input without a DC link by segmenting and recombining portions of the input waveform through phase-controlled devices. A step-up cycloconverter produces an output frequency higher than the input by proper gating and polarity reversal within smaller time windows.
Given Data / Assumptions:
- Input frequency = 50 Hz, period T.
- Output frequency = 100 Hz, period T/2.
- Ideal switching and sufficient device count are assumed.
Concept / Approach:
For a frequency-doubling (50 → 100 Hz), the converter must produce a complete output cycle in half the input period. Thus, within one input half-cycle (duration T/2), the control scheme constructs both the positive and negative half-waves of the output in sequence to total one full 100 Hz cycle.
Step-by-Step Solution:
Let input period be T (for 50 Hz).Output period needed is T/2 (for 100 Hz).Within one input half-cycle of duration T/2, synthesize a full 100 Hz cycle (positive + negative half-waves) by appropriate device gating.Verification / Alternative check:
Frequency-doubling control waveforms for step-up cycloconverters in textbooks show exactly one output cycle generated during each input half-cycle.
Why Other Options Are Wrong:
Half wave (a) is insufficient; two full waves (c) would imply 200 Hz; (d) is incorrect for a fixed 2:1 step-up; (e) contradicts operation.
Common Pitfalls:
Assuming cycloconverters only step down; overlooking polarity inversion and gating schemes required to synthesize the higher frequency.
Final Answer:
One full wave of output