In a three phase half controlled rectifier with constant current load and freewheeling diode, what is the fraction of cycle the diode conducts? Consider firing angle $$(\alpha)$$ of thyristors greater than $$60^\circ$$.

A

$$\frac{\left(\alpha - \frac{\pi}{3} \right)}{2 \pi}$$

B

$$\frac{\left(\alpha + \frac{\pi}{3} \right)}{2 \pi}$$

C

$$\left(\alpha - \frac{\pi}{3}\right) \times \frac{3}{2 \pi}$$

D

$$\left(\alpha + \frac{\pi}{3}\right) \times \frac{3}{2 \pi}$$