multiphase drives for ev applications eecomobility (orf) · 2019. 10. 8. · ahmed salem why...
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![Page 1: Multiphase Drives for EV Applications EECOMOBILITY (ORF) · 2019. 10. 8. · Ahmed Salem Why Multiphase Drives Modulation Techniques 1. Space Vector Modulation (SVPWM) Based on Vector](https://reader036.vdocuments.net/reader036/viewer/2022071008/5fc55ecef7172f204d07a057/html5/thumbnails/1.jpg)
We acknowledge the support of the NaturalSciences and Engineering Council of Canada(NSERC), which invests annually over $1billion in people, discovery and innovation.
EECOMOBILITY (ORF) &HEVPD&D CREATE
We acknowledge the support ofthe Ontario Research Fund:Research Excellence Program.
Multiphase Drives for EV ApplicationsCentre for Mechatronics and Hybrid TechnologyElectrical and Computer Engineering, McMaster UniversityAhmed Salem
Why Multiphase Drives
Modulation Techniques1. Space Vector Modulation (SVPWM) Based on
Vector Space Decomposition (VSD):Pros:• Full control of voltage vectors in different subspaces• Compensation of non-torque production harmonics.Cons:• Requires high computational power.• Requires additional controllers to compensate the effects ofmachine back EMF’s.
Sa1
Sa2
Sa3Sa4
Sa5
Sa6
Sa1
Sa2
Sa3Sa4
Sa5
Sa6
—
A
— —
— —
—
-
+
Vdc
Multiphase Drives Features:1. Lower Power/Current Rating per Phase.2. Fault-tolerance operation.3. Torque density improvement.4. Lower Dc-Link Current Ripples.
Calculate Ixy0+0-*
Calculate Loss function
Min(Loss) using global
Optimization A
Increase Tref & evaluate Iαβ*
Possible global Minima
No
A
Applying constraints
Calculating Ia1b1c1a2b2
Yes
Record Values of K in look up table against
the Tref
End
Il <= In (l = a1, b1, c1, a2, b2)& Ic2 =0
Start
Project StatementObjectives:• Develop a six-phase
inverter based on the requirements of the drive.
• Reduce the size of the DC-link bank of capacitors.
Tasks:• Literature review on multiphase
drives.• Build up a scaled down prototype
of six-phase inverter.• Developing new control technique.• Developing new switching
technique for the capacitor sizing.
The figure shows a schematic of one phase-leg of the inverterused in Tesla Model S which has for the upper part 6 switchesconnected in parallel. The inverter comprises of 36 IGBT in total.The multiphase concept overcomes the problems associatedwith paralleling IGBT’s.
c2 b1c1b2 a2
30º
120º 120º n
C2 B1C1B2 A2
N
- +Vdc
A1
a1
3-Phase Inverter
3-Phase Inverter
T1
Fault-Tolerance Capability
8, 42
27
10
3 , 59
1714
24, 31
19
26
18
302, 58
51
16, 23
28
5022
6, 62
20
54 48, 55
38
56
60, 4
53
36
39, 32
44
37
61, 5
494621
3412
35
29
47
16,
27
52922
45
26
36
1154
41
18
37
45,
3534
42
46
14 44
10
38
43 50
59, 339, 32
58, 2
47, 40
6, 62
8, 15
30
12
4, 60
13 20
5, 6124, 31
2928
0+
0-
0, 9, 10, 12, 17, 18, 20, 27, 29, 30, 33, 33, 32, 36, 43, 45, 46, 51, 53, 54, 63
8, 16, 25, 26, 28, 32, 41, 42, 44, , 49, 50, 52, ,59, 61, 62
24, 40, 48, 57, 58, 60
56
1, 2, 4, 11, 13, 14, 19, 21, 22, 31, 35, 37, 38, 47, 55
7
3, 5, 6, 15, 23, 39
2. SVPWM based on voltage classification method
Using two references Using one reference
Pros: Simple technique in implementationCons: Unable to eliminate the xy subspace harmonics.
• Unlike Three-phase drives, Multiphase drives operates with hightorque range under faulty conditions.• Three-phase drives has 29% maximum output torque withoutput torque ripples under optimal current control.• Six-phase Drives under one-phase loss can operate up till69.5% under optimal current control with no torque ripples andminimum losses..Remedial Solution to increase the torque range under single-phase faults:• The proposal is to provide a neutral connection to the dc-linkmidpoint and by applying global optimization the torque rangereaches 81.6% which represents 11% increasement.
Results:
0 10 20 30 40 50 60 70 80 90 100
Torque Range %
0
20
40
60
80
100
Stat
or C
oppe
r Los
s %
Without Neutral
With Neutral
Healthy