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T
k
=
|
V
ref
|
sin
(
kπ/
5
−
γ
)
T
s
|
V
l
|
sin
(
kπ/
5)
T
k
=
|
V
ref
|
sin
(
γ
−
(
k
−
1)
π/
5)
(19)
T
s
|
V
l
|
sin
(
kπ/
5)
T
0
=
T
s
−
T
k
−
T
k
+1
where
|
V
l
|
is the amplitude of the largest vector.
4 Vector Control of Five-Phase PMSM
Based on decoupled mathematic model, the scheme of rotor field oriented control
for five-phase PMSM is presented, shown in Fig.5.
In the Fig.5 there is the current control in the two subspaces which are
α
1-
β
1
and
α
3-
β
3. The field oriented control
i
d
= 0 is adopted. The
i
d
1
=0and
i
d
3
=0
are zero. The
i
q
1
= 0 is the output of speed PI regular similar to the traditional
vector control of three-phase PMSM.
The difference between the three-phase and five-phase is appliance of the three
harmonic torque according to (5). In the Fig.5, the
i
q
3
= 0 reference is calculated
according to the
i
q
1
= 0. The coecient
K
q
3
from
i
q
1
=0to
i
q
3
= 0 is dependent
on the rotor design and the limitation of VSI current. In most field, can be set
as zero. At this time
K
q
3
is zero.
After the calculation of four PI regulators, the voltage reference
i
q
3
=0
is obtained in the corresponding subspace. Before the SVPWM calculation,
these reference need to be converted in the stationary coordinate by the
T
−
1
(
θ
)
module.
u
V
dc
d
1
i
0
PId1
PIq1
1
i
u
q
Z
i
PIv
ABC
VSI
u
PWM
MOTOR
i
0
d
3
PId3
PIq3
3
u
i
q
3
i
K
DE
3
q
3
i
1
i
Z
T
T
()
i
3
i
3
Fig. 5.
Rotor field oriented control of five-phase PMSM
5 Simulation and Experiment Analysis
The SVPWM waveform in the No.1 section is shown in Fig.5. The action time
T
0
and
T
2
is calculated by (19). In one switching period, each device switches
on and switches off only once.
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