Different Novel Electric Machine Designs for
Automotive Applications
G. Dajaku
FEAAM GmbH
Neubiberg, Germany
� Introduction, Concentrated Winding
� New Stator Design with Flux-Barriers
� Self-Excited Synchronous Machine
� Different Novel Winding Topology for PMSMs and ASMs
� ASM with Concentrated Windings
� Conclusions
Overview
2
� Main Requirements
� FSCW are increasingly used in several industry application !!
Introduction
3
High Power Density High Efficiency Low Costs
� Limited volume
� Weight
� Energy price & Co2
� Battery capacity
� Materials
� Manufacturing
SOLUTIONS – State of the Art
� PM machines
(NdFeB, SmCo)
� FSCW
- High winding factor
- Short end-winding
� Low losses
(iron, copper, magnets)
� FSCW
- Short end-winding
- High filling factor
� FSCW
- Simple manufacturing
- Short end-winding
� Other machine types
(ASM, CESM, SynRel,
etc.)
FSCW - Fractional slots tooth
concentrated winding
� Main Characteristics
Concentrated Windings
4
� Advantages
� Compact design
� Simple manufacturing
� Short end winding
� High winding factor
� Low copper losses
� Disadvantages
� High space harmonics
o Rotor losses
o Noise and vibrations
� Realization
� Single- or double-layer
� Tooth concentrated
Winding MMF
� Realization: 12-Teeth/10-Poles
Concentrated Windings
5
++High winding factors:
SL DL
ξ5 =0.966 ξ5 =0.933
ξ7 =0.966 ξ7 =0.933
1. Single-layer 2. Double-layer
0 2 4 6 8 10 12 14 16 18 200
0.2
0.4
0.6
0.8
1
1.2
1.4
Space Harmonics
MMF [ p.u. ]
Single-Layer
Double-Layer
-Losses, noise and vibration
- 5th or 7th => working harmonic
MMF Winding Characteristics
Reduction of the Winding MMF-harmonics
6
Using magnetic flux-barriers
1. Flux-barriers in stator yoke* (*ICEM-2012)
2. Flux-barriers in stator teeth* (*EDPC-2012)
Modifying winding
3. Different turns per coil-side* (*ICEMS-2011)
4. 24-Teeth/10-Poles* (*IEMDC-2011)
5. 18-Teeth/10-Poles* (*IEMDC-2013)
6. 36-Teeth/10-Poles
1). 2).
3).
4).
flux-barriers
� Self-excited SM: Rotor excitation through MMF harmonics
Permanent Magnet Machines
7
� Flux-Barriers in Stator Teeth
Flux barriers
0 2 4 6 8 10 12 14 16 18 200
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Harmonic Order
B [ T ]
Conv. Stator
New Stator-73% -19%
+16%
� Simple manufacturing; Efficiency cooling; Modular structure
� Reduction of material costs and space up to 20%
� High Efficiency
� Improved field weakening
� Available efficiency cooling
Comparison of Results for a PM Machine
8
0
1
2
3
4
0 40 80 120 160 200
T [Nm]
rotor position [el. degree]
Ieff=70A: Electromagnetic Torque
Conv. Stator (Lstk=70mm)
New Stator (Lstk=58,8mm)
0
10
20
30
40
50
60
70
80
90
P [ W ]
P_Cu P_Stator P_Rotor P_MagnetsIron Iron v
Losses
Conv. Stator (Lstk=70mm)
New Stator (Lstk=58,8mm)
� Conv. Design: Da = 80mm, Lstk = 70mm
� New Design: Da = 80mm, Lstk = 58.8mmVolume:
Analogous PM Machine with FB
9
� Requirements
0,0
0,5
1,0
1,5
2,0
2,5
500 1000 1500 2000 2500
Te [Nm]
Speen [rpm]
Irms=10A
Irms=15A
Irms=20A
Irms=25A
Irms=30A
Flux-barriers (non-
magnetic material)
� New Concentrated Winding, 18-Teeth/10-Poles
� Low harmonic contents
� High slot fill factor
� Short end-winding length
� Simple construction
Self-Excited CESM with Concentrate Winding
10
MMF winding characteristics
0 5 10 15 200
0.2
0.4
0.6
0.8
1
Harmonic Order
MMF [ p.u. ]
12-Teeth/10-Poles
18-Teeth/10-Poles
PM
SynRel
CESM
� Fundamental Construction
Self-Excited CESM with Concentrate Winding
11
Main Characteristics
� Brushless current excited synchronous machine
� Simple tooth concentrate winding for the both stator and rotor
� The 5th MMF harmonic is used as working harmonic
� The 13th MMF harmonic is used as excitation harmonic
Block Circuit-Diagram for the New Machine
0 5 10 15 200
0.2
0.4
0.6
0.8
1
Harmonic Order
MMF [ p.u. ]
MMF 18T/10P
Working
harmonic
Excitation
harmonic
Simulation Results
12
� Exemplary Machine
� Da = 230 mm
� Lstk = 150 mm
� UDC = 400 V
� Imax = 650 A
� nmax =12000 rpm
-50
0
50
100
150
200
250
300
350
0 60 120 180 240 300 360
T [Nm]
time [ms]
1). n = 5100 rpm, Ieff = 500A
0
50
100
150
200
250
300
0 0,5 1 1,5 2 2,5
T [Nm]
time [ms]
2). n = 600 rpm, Ieff = 650A
2)
1)
Different Winding Topologies with
Low MMF Harmonic Contents
13
� 24-Teeth/10-Poles Winding
24-Teeth/10-Poles Machine
0 5 10 15 20 250
0.2
0.4
0.6
0.8
1
Harmonic Order
MMF [ p.u. ]
� 36-Teeth/10-Poles Winding
MMF [ p.u]
Harmonic Order
24-Teeth/10-Poles ASM
14
� ASM Prototype Machine � Efficiency Map (Experimental Results)
Comparison of Two ASM for Traction Applications
15
A). 90-Teeth/10-Poles ASM with the conv. winding
B). 36-Teeth/10-Poles ASM with the new winding
Machine specifications Reference machine
Conv. Design
New Design-1 New Design-2
Active langth 63 mm 70 mm 65 mm
Nr. of poles 10 10 10
Stator outer radius 151 mm 151 mm 151 mm
Shaft radius 99,5 mm 99,5 mm 99,5 mm
Max. Efficiency difference - +2,6%
-0,3%
+0,3%
-0,3%
Copper reduction - 0% 15,5%
A B
� Series Connection of Rotor Bars
New Rotor Design for ASM with CW
16
Winding MMF
ASM: 9-teeth/8-poles
End-Ring Module
Conclusions
17
High Power Density High Efficiency Low Costs
� Limited volume
� Weight
� Energy price & Co2
� Battery capacity
� Materials
� Manufacturing
New SOLUTIONS: E-machines with Concentrated Windings and,
� Flux-barriers (PMSM, SynRel): >> up to 20% material costs and volume reduction,
high efficiency
� Self-excitation (CESM): >> low costs design, small volume, high efficiency
� New Windings (PMSM, CESM, ASM, SynRel):
>> high efficiency & power-density, low costs
� New ASM Rotor: >> low costs, high efficiency
� Torque Pulsations Reduction: >> low costs, high efficiency