
10-6 Power Electronics and Motor Drives
phasors v
s
and
I
s
whose moduli correspond to the variable rms values. e use of Equation 10.5 leads to
e
xpress the voltage and current space phasors as follows:
v V e
i I e
s
s
s
s
j t
v
j t
v i
=
=
−
− −
2
2
( )
( )
ω ϕ
ω ϕ ϕ
(
10.9)
ese vectors present constant moduli and rotate at positive ω angular speed.
In
c
ase
o
f
a
n
a
nticlockwise
v
oltage
s
ystem
v V t
q
s s
q v
= + −2 cos( )ω ϕ∆
,
t
he
q
expression becomes
t
s s
= + − −2 co s( )ω ϕ ϕ∆
.
e
c
orresponding
s
pace
p
hasors
t
hat
r
esult
f
rom
t
he
u
se
o
f
E
quation
1
0.5 can be written as
v V e
i I e
s
s
s
s
j t
v
j t
v i
=
=
− −
− − −
2
2
( )
( )
ω ϕ
ω ϕ ϕ
(10.10)
ese vectors rotate ...