A single - phase fully controlled thyristor bridge ac -

A single - phase fully controlled thyristor bridge ac - dc converter is operating at a firing angle of 25° and an overlap angle 10° with constant dc output current of 20 A. The fundamental power factor (displacement factor) at input ac mains is

I₀ =	V_m	[cosα - cos(α + μ)]
	ωL_s

∴ 20 =	2 × √2	[cos25° - cos(25 + 10)]
	2 × π × 100L_s

L_s = 0.0045 Henery

V_o =	2 × √2 × 230
	π

cos25° -	2 × π × 50 × 0.0045	× 20 = 178.65
	π

∴ Displacement factor =	V_o I_o
	V_s I_s

=	178.65	×	20	= 0.78
	230		20