Page 221 - Power Electronics Handbook

Performance factors 2 I1

(C)
9.35 Waveforms used in calculating load d.c. voltage for ap-pulse converter

waveforms has now been moved to the commencement point for overlap,
the two waveforms being given by equations (9.7) and (9.8).

v, = J(2)Vcos (9-7)

v, = J(~)VCOS (9.8)

During the overlap period the load voltage assumes a value intermediate
between V, and V, so that the d.c. voltage is given by equation (9.9).

PJI:
= J(2) V sin - (1 + cos p)
P
P I C
-
= 42) v ; cos2 E
sin
P 2
= v,, cos2 -E
2
Therefore the effect of overlap is similar to that of firing angle delay in
that the mean output voltage is reduced, although the extent of variation in
the two cases is different. For circuits operating with delay (Y and overlap
angle p, the value of mean d.c. voltage is given by equation (9.10).

VavCa) = v,,COsLycos 2P - (9.10)
2