Question

for rectifier operation theoretically ignition angle range between​

Answer 1

Explanation:

Firstly, the situation you are defining, is not called as 'rectification mode' but 'inversion mode' when the dc bus voltage polarity is reversed. Secondly, a simple R-L load does not support this situation: there must be a source of energy on the dc side, with correct polarity so that current flows through the SCR's in the forward direction only, eg a battery connected with its polarity reversed to the normal rectification mode bus voltage polarity.

Now, if the firing angle is more than 90 deg, then the delay angle of input ac current is also more than 90 deg. Let us simply assume that the fundamental current is now lagging by more than 90 deg, The input power on ac is V*I*cos<alpha> where <alpha> is more than 90 deg, implying power input is negative as cos<theta> is now negative. Thus, now power is flowing out and not in to the ac side input. remember that the power is now flowing out from the dc side energy source to the ac line.