Operation and Design of Multilevel Inverters Dr ... - MotorLab.com

voltage. This magnetizing voltage can be expressed in terms of the transistor signals
and dc voltage as
1
vam = −
2
( TaL
TaR
) vdc
From (3.2-23), the magnetizing current can be calculated by
(3.2-23)
vam
p iam
= (3.2-24)
L
Once the magnetizing current is known, the left and right reactor currents can be
found by solving the two unknowns from the two KCL equations
asL
asR
Copyright 2005. K.A. Corzine 24
m
i − i = i
(3.2-25)
asL
asR
am
i + i = i
(3.2-26)
Considering (3.2-23), it can be seen that the redundant states in Table 3.2-6 can
make the magnetizing voltage positive or negative effecting the change in i am
according to (3.2-24). This can be used to control i am to zero yielding zero
differential mode current according to (3.2-25) so that i asR = iasL
.
It should be pointed out that the material presented herein shows the fundamental
example. Extensions of this material include paralleling multi-level phases [7],
combining the parallel topology with an H-bridge structure [28], and paralleling
more than two phases.
as