
Fundamentals of AC–DC–AC Converters Control and Applications 16-31
Assuming initial steady-state operation,
m
=
mc
= const. and U
dc
= U
dcc
= const., the transfer function
of the AC–DC–AC converter–fed IM drive can be described.
Based on above considerations, it can be concluded that introduced active PF has no negative impact
on the line current. is can be derived analytically. Please consider rotating reference frame concur-
rently with VF. With assumption that the system is decoupled, and meets the UPF condition, i.e., I
Lx
= 0,
the following equations can be derived:
L
dI
U U RI
Ly
Ly py Ly
= − −
(16.79)
C
dU
dt
I
U
U
I
dc
Ly
py
dc
load
= −
(16.80)
L
dI ...