GATE 2024 EE – Question 62
A single-phase half-controlled bridge converter supplies an inductive load with ripple free load current. The triggering angle of the converter is 60°. The ratio of the rms value of the fundamental component of the input current to the rms value of the total input current of the bridge is __________ (rounded off to 3 decimal places).
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Correct answer: 0.94 to 0.96
Explanation
With ripple-free load current $I_o$, the input current is a quasi-square wave of height $\pm I_o$ conducting for $\pi-\alpha$ in each half-cycle. Its rms value is $I_o\sqrt{1-\dfrac\alpha\pi}$, and the rms of the fundamental is $\dfrac{2\sqrt2}{\pi}I_o\cos\dfrac\alpha2$. For $\alpha=60^\circ$: $\dfrac{0.9003\times0.8660}{\sqrt{2/3}}=\dfrac{0.7797}{0.8165}=0.955$.