Md Zarafi Ahmad, Erwan Sulaiman, Zainal Alam Haron, Faisal...
Transcript of Md Zarafi Ahmad, Erwan Sulaiman, Zainal Alam Haron, Faisal...
9/15/20141
Md Zarafi Ahmad, Erwan Sulaiman, Zainal Alam
Haron, Faisal Khan, and Mubin Aizat Mazlan
Dept. of Electrical Power Engineering
Faculty of Electrical and Electronic Engineering
Universiti Tun Hussein Onn Malaysia
World Virtual Conference on Advanced Research in
Mechanical and Materials Engineering, 2014
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OUTLINES
1• Introduction
2• Design Restrictions and Specifications
3
• FEA-Based Performance Analysis• Improved Design Structure
• Flux Characteristic at Various Current Densities
• Cogging Torque
• Induced Voltage
• Torque and Power Profile
4 • Conclusion
INTRODUCTION
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Fig. 1 Classification of electrical machines
INTRODUCTION
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• High performance application of AC
machines required:
i. High torque density
ii. High power density
iii. High reliability
iv. High efficiency
INTRODUCTION
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• Previously, the
interior permanent
magnet
synchronous
machines (IPMSM)
are mostly used in
electric vehicle (EV)
A better machine such as flux switching machine (FSM) is selected
5. Complex structure
Problems of IPMSM
4. Low rotor mechanical strength- Necessity of large no. of bridges- Less robust in high speed condition
1. Distributed armature windings - Longer coil end length- High copper loss
3. High PM volume (1.1kg)
2. Constant PM flux
INTRODUCTION
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• However, most of research done on FSMs are focused
on inner-rotor configuration and hard to find report on
outer-rotor configuration.
• Lately, an outer-rotor PM FSM for in-wheel drive has
been proposed for light traction EV applications
• Nonetheless, with constant PM as a main flux
source, it also may suffer from demagnetization and
un-controllable flux.
• Thus, this research presents analysis of a new dual
excitation flux switching machine (DEFSM) with outer-
rotor configuration for In-Wheel Drive EV. PM
DC Field Excitation
DESIGN CONDITIONS AND SPECIFICATIONS
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Items Unit
Outer-
rotor
DEFSM
Geometrical
dimension
and volume
Motor diameter mm 264
Motor stack length mm 70
Shaft radius mm 30
Air gap length mm 0.8
PM weight kg 1.0
Input voltage
and current
Max. DC-bus voltage inverter V 650
Max. inverter current Arms 360
Max. armature current
density, Ja
Arms/mm2 30
Max. FEC current density, Je A/mm2 30
Output
performances
Maximum torque Nm 333
Maximum power kW 123
Machine weight kg 30
Power density kW/kg 4.1
Table I. Design conditions and specifications of outer-rotor DEFS Motor
DESIGN CONDITIONS AND SPECIFICATIONS
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Fig. 3 Initial design
Non-Overlap windingAC
PM Rotor
FEC
Rotor pole width = Stator
tooth width
PM and AC at least 1/3
of stator body
Rotor depth 15%-20% of
machine’s radius
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Design Improvement Process
Fig. 4 Design parameters
Fig. 5 Optimization process
Start
Deterministic Optimization
Tn (Nm), Pn (kW), (n=1)
n = n + 1
Vary rotor parameters
D1, D2, D3
Vary PM parameters
D5, D6
Vary FEC Slot Parameters
D7, D8
Vary Armature Slot
Parameters D9, D10
Tn = In +1
Pn = Pn + 1
End
No
Yes
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Fig. 6 Initial design Fig. 7 Improved design
Tmax = 243.52 Nm
Pmax = 110.31 kW
Tmax = 298.46 Nm
Pmax = 138.75 kW
3. Design Improvement Process
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FEA BASED PERFORMANCE ANALYSIS
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0 3 6 9 12 15 18 21 24 27 30 33 36
ϕ [Wb]
Rotor [º]
Je=0 Je=5 Je=10 Je=15
Je=20 Je=25 Je=30
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0 3 6 9 12 15 18 21 24 27 30 33 36
ϕ [Wb]
Rotor [˚]
Je=0 Je=5 Je=10 Je=15
Je=20 Je=25 Je=30
(a) Original design (b) Improved design
Fig. 8 U-phase flux linkage
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FEA BASED PERFORMANCE ANALYSIS
Fig. 9 Cogging torque Fig. 10 Back-emf
-5
-4
-3
-2
-1
0
1
2
3
4
5
0 3 6 9 12 15 18 21 24 27 30 33 36
T [Nm]
Rotor position [°]
Improved design Original design
-200
-150
-100
-50
0
50
100
150
200
0 3 6 9 12 15 18 21 24 27 30 33 36
Back-emf [V]
Rotor [°]
Improved design
Original design
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FEA BASED PERFORMANCE ANALYSIS
Fig. 11 Torque and Power vs Speed
0
20
40
60
80
100
120
140
160
0
50
100
150
200
250
300
350
0 5000 10000 15000 20000
P [kW]T [Nm]
Speed [r/min]
Improved design Initial Improved design Initial
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CONCLUSION
This paper has discussed and demonstrated the
design analysis improvement on 12slot-14pole
DEFSM with outer-rotor configuration.
Some improvement on the torque and power has
been achieved which give the torque density and
power density of 10.19 Nm/kg and 4.74
kW/kg, respectively.
Further design investigation and improvement will
be conducted to achieve the target performances of
torque and power.