Download Initial Design of 12s-10p and 12s-14p with Outer

The 2nd Power and Energy Conversion Symposium (PECS 2014)
Melaka, Malaysia
12 May 2014
Initial Design of 12s-10p and 12s-14p with OuterRotor Field-Excitation Flux Switching Machine
Syed Muhammad Naufal Syed Othman, Erwan Sulaiman, Mohamed Mubin Aizat Mazlan, Zhafir Aizat Husin
Universiti Tun Hussein Onn Malaysia, Locked Bag 101, Batu Pahat, Johor, 86400 Malaysia
[email protected], [email protected]
Abstract—This paper shows the initial design of Outer-Rotor
Field Excitation Flux Switching Machine with 12slot-10 pole and
12slot-14pole as an alternative for a non-permanent magnet flux
switching machine. The performance, design specification and a
no-load test is presented. All excitation sources such as armature
winding and field winding is located at the stator, although the
stator at the inner and rotor at the outer part. Furthermore,
salient pole is used to modulate and switch polarity of the flux
linkage in the armature winding, while the rotor comprise only
stack of iron only.
Armature Coil
(a)
(b)
Index Terms—35H210, copper, FEC coil, 2D-Finite Element
Analysis, ORFEFSM, FEFSM, IPMFSM
I. INTRODUCTION
Armature Coil
In this day, Induction Permanent Magnet Flux Switching
machine is one of the most successful candidate for a high
torque, speed and power density especially in the sector of
transportation such as hybrid electric vehicle. The common use
for a high torque and high speed rating is the 3-phase system
used worldwide. Flux switching machine(FSM) comprise of
Permanent Magnet(PM), Field Excitation(FE) and Hybrid
Excitation. Of all the three classification of FSM, field
excitation is the best candidate with a decent performance with
a low cost of manufactured. Hence, FEFSM motor has a huge
advantages in the construction (simple), magnet-less, and
variable flux control capabilities which suitable for various
performances. Since the permanent magnet is being used
widely in research for a better optimization, making the usage
of rare earth magnet to increase in demand. FEFSM do perform
magnetization but from the magnetic field of the coil differ
from the PMFSM, which magnetization performs from the rare
earth magnet itself. Filed excitation flux switching machine
perform distinct compared to PMFSM and HEFSM, because it
us field excitation to generate flux. The basic operation of the
motor is based on the principle of switching flux. It describe
machine as the stator tooth flux switches the polarity followed
with the motion of the salient pole rotor. It can be illustrated in
the following Figure 1(a), (b), (c) and (d). Figure 1(a) and (b)
shows how the flux of FEC direction unto the rotor while
Figure 1(c) and (d) illustrates the FEC fluxes unto the stator
and hence completed a one cycle of flux. The transition
between Figure 1(a) and (b) causes the stator flux to switch
between the stator tooth alternate tooth
(c)
(d)
Figure 1: Principle operation of FEFSM (a) θe=0° and (b)
θe=180° flux moves fromstator to rotor (c) θe=0° and (d)
θe=180° flux moved from rotor to stator
II. DESIGN RESTRICTION, SPECIFICATIONS AND PROCEDURES
FOR HYBRID ELECTRIC VEHICLE APPLICATIONS
Table 1 shows the design restriction, specification for
outer-rotor FEFSM with 12S-10P and 12S-14P. 650V of DC
bus voltage and 360A of maximum inverter is the electrical
restrictions that are set. As for the limitation of current density,
it is set to a maximum 30Arms/mm2 for armature winding and
30A/mm2 for FEC respectively. The main part of the design
such as outer diameter, motor stack length, shaft radius and air
gap are restrict to 264mm, 70mm, 30mm and 0.8mm. Since it
consists of only iron stack sheets, it can be assumed that it is
mechanically robust to rotate at high speed.
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The 2nd Power and Energy Conversion Symposium (PECS 2014)
Melaka, Malaysia
12 May 2014
TABLE I
DESIGN SPECIFICATIONS AND PARAMETERS
FOR 12S-10P
(12S-10P)
Max. DC-bus voltage inverter (V)
Max. inverter current (A)
Max. current density in armature
winding, Ja (Arms/mm2)
Max. current density in excitation
winding, Je (A/mm2)
Number of phase
Number of stator poles
Number of rotor poles
Outer diameter of motor (mm)
Motor stack length (mm)
Rotor radius (mm)
Air gap length (mm)
Rotor pole width (mm)
Rotor pole depth (mm)
FEC width (mm)
FEC depth (mm)
Armature coil depth (mm)
Armature coil width (mm)
FEC 1
(mm)
650
360
30
30
3
12
10
264
70
132
0.8
52
10.82
2.7652
53.04
53.04
3.1674
Figure 4 12S-10P FEFSM windings(FEC 1)
FEC 2
The machine configuration and windings are illustrated in
Fig. 3 and Fig. 4, respectively. From configuration, the FEC
are allocated uniformly between each armature coil slot and
alternate FEC and armature coil slot around the stator. The
directions of FEC are in counter-clockwise polarity and
clockwise polarity, while the three phase armature coils are
placed in between them.
Figure 5 12S-10P FEFSM windings(FEC 2)
Rotor
Stator
Armature
Coil
TABLE II
DESIGN SPECIFICATIONS AND PARAMETERS
FOR 12S-14P
Shaft
(12S-10P)
Max. DC-bus voltage inverter (V)
Max. inverter current (A)
Max. current density in armature
winding, Ja (Arms/mm2)
Max. current density in excitation
winding, Je (A/mm2)
Number of phase
Number of stator poles
Number of rotor poles
Outer diameter of motor (mm)
Motor stack length (mm)
Rotor radius (mm)
Air gap length (mm)
Rotor pole width (mm)
Rotor pole depth (mm)
FEC width (mm)
FEC depth (mm)
Armature coil depth (mm)
Armature coil width (mm)
Figure 3 Design configuration of 12S-10P outer-rotor FEFSM
178
(mm)
650
360
30
30
3
12
14
264
70
132
0.8
38.92
10.82
2.7652
53.04
53.04
3.1674
The 2nd Power and Energy Conversion Symposium (PECS 2014)
Melaka, Malaysia
12 May 2014
As for 12S-14P, the number of FEC and armature
winding is same as 12S-10. Figure 6 below show the diagram
for 12S-14P. All of the design is come from commercial finiteelement analysis (FEA), the JMAG Designer 12.1 version. In
which, it is release by Japan Research Institute(JRI) as a way to
perform a 2D-FEA.
Rotor
Stator
Armature
Coil
Figure 8.Flux linkage of 12S-14P FEFSM phase U, V and W
Shaft
Coil test is intended to satisfy whether the machine manner
at the U flux at the zero rotor position. Since the U flux value
is 0 Wb at the condition of 90º and 270º, while it’s at
maximum value during 180º it shows that conditions has been
fulfilled.
B. FEC flux linkage at varies FEC current density, JE
Figure 9 and 10 shows the U phase flux linkage when
supplying current at various FEC for design 12Slot-10Pole
ORFEFSM and 12S-14P ORFEFSM while Figure 11 and 12
show the maximum U phase flux linkage when Je=0 A/mm2
until Je=30A/mm2.
Figure 6 Design configuration of 12S-10P outer-rotor FEFSM
III. DESIGN RESULTS AND PERFORMANCES BASED ON 2DFINITE ELEMENT ANALYSIS
A. Coil Arrangement Test
Coil arrangement tests are performed in order to identify
each armature coil separately. What is the operating principle
of the outer-rotor FEFSM and to set the position of each
armature coil phase, where all armature coils are wounded in
counter-clockwise direction while FECs are wounded in
clockwise and counter-clockwise direction. The flux linkage at
each coil is observed and the armature coil phases are defined
according to the conventional three-phase system. Fig. 5
demonstrates the flux linkage of all coils at separate phase as
three-phase flux linkage defined as U, V, and W, respectively.
The flux produced relatively smooth as there is no distortion
occurs.
Figure 9. U phase Flux linkage at varies FEC current density, JE
Figure 7.Flux linkage of 12S-10P FEFSM phase U, V and W
179
The 2nd Power and Energy Conversion Symposium (PECS 2014)
Melaka, Malaysia
12 May 2014
Figure 10. U phase Flux linkage at varies FEC current density, JE
where it is not. Meanwhile, the gap between the shaft and
stator is small; the flux density there should be saturated.
From the JE characteristic graph, the flux increases to
5A/mm2 then decrease at 10A/mm2 considered constant until
30A/mm2. This is because the material used for FEC, copper,
has reached its limit to produce flux. Besides, inside the
motor, there is some flux that flow in opposite direction thus it
will cancelled each other. From both graph, it shows that the
maximum value is different, 12S-10P shows a higher
maximum value 0.0085 Wb when Je=5 A/mm2, while 0.0060
Wb for 12S-14P.
Figure 14.Illustration of flux distribution of the three-phase 12S-10P
ORFEFSM
Figure11. Maximum U phase flux (12S-10P) at varies FEC current density,
JE.
Figure 15.Illustration of flux distribution of the three-phase 12S-14P
ORFEFSM
D. Cogging Torque
Figure 16 show the cogging torque graph. This graph is
plotted when JE equal 30 A/mm2 and JA equal 0 Arms/mm2
which no current being supply to armature coil. One cycle is
formed as the rotor being rotate 6°. There are 6 cycles formed
as another 6 cycles are exactly the same as previous. It shows
that the rotor is in synchronizing rotation. From both design,
the amplitude of each cycle for 12S-10P is higher (6Nm)
compared to 12S-14P (4Nm). A high cogging torque can
create a disturbance if it do not exceed 10 per cent of the total
torque it produce.
Figure12. Maximum U phase flux (12S-14P) at varies FEC current density,
JE.
C. Flux Distribution
Flux distribution test is about the flux distribution around
the motor. It can classify into many types of color in order to
determine its density. The highest value of the parameter is the
one that being set during the plot. From the Figure 13, the
highest set value is 2.4000T while the maximum value during
the operation of the motor is 2.2959T. The condition during
this test perform is at Je=30 A/mm2, and Ja=30 A/mm2, where
the armature and FEC current supply is at maximum.
Figure 15 show a different value of flux density compared
to Figure 14, this is because the maximum value is 2.3042 T.
From here, we can determine where the flux is saturated and
180
The 2nd Power and Energy Conversion Symposium (PECS 2014)
Melaka, Malaysia
12 May 2014
ACKNOWLEDGMENT
This research was supported by Geran Insentif Pelajar
Siswazah(GIPS, vot 1368) under
Research, Innovation,
Commercialization and Consultancy management(ORICC)
University Tun Hussein Onn Malaysia(UTHM), Batu Pahat
and Ministry of Higher Education Malaysia(MOHE).
REFERENCES
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Figure 16.Cogging Torque of 12S-10P FEFSM
Figure 17.Cogging Torque of 12S-14P FEFSM
CONCLUSION
As for the conclusion design studies and performance
analysis of an outer-rotor 12S-10P, 12S14P FEFSM are
presented. The design of the proposed motor is quite
complicated because of the opposite configuration which
exposes in more core loss than inner-rotor. Besides, it is better
way of design when compared with inner-rotor FEFSM. There
is no usage of permanent magnet and thus, it can be expected
as very low cost machine. In addition for future research the
final design of outer-rotor FEFSM will have a robust rotor
structure with high mechanical strength suitable for high speed
motor applications. Therefore, it is reasonable to say that the
proposed machine will be good candidate as a non-permanent
magnet machine for HEV drives and achieve target
performance.
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