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ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling Universität der Bundeswehr München

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Page 1: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

-

Advantages and Challenges

Dieter Gerling

Universität der Bundeswehr München

Page 2: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

development of costs for battery packs

2

estimated for Chevy Bolt

estimated for Tesla Model S

● ●

estimated for Tesla Model 3 (Gigafactory)

Page 3: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

standard system up to now for high power traction

3

= 3 ̴ M

ca. 375V ca. 150V

Page 4: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

possible system architecture with low voltage DC circuit

4

electrical machine

power electronics DC electrical system

M

48V

⁞ ⁞

battery

Page 5: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

stator „winding“ evolution

5 Quelle: derkonstrukteur.de

distributed winding

concentrated winding

stator cage winding

Page 6: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

building the entire electrical drive

no more coils, massive stator cage instead

perfect utilization of available space: • perfect slot filling factor • no end-windings

great thermal behavior • low thermal resistance bar – iron • water cooled end-ring possible

minimum production cost • aluminum instead of copper • simple production, e.g. die-casting, low invest

extremely smooth rotating field • individual bar currents • very high efficiency

6

Page 7: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

ISCAD (Intelligent Stator Cage Drive) e.g. as induction motor with changing number of poles during operation

7

Page 8: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

changing the number of pole pairs during operation (exemplary calculation)

8

p=3

p=2

p=1

Page 9: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

best-in-class overload capability

9

This overload area can be used by ISCAD (machine and power electronics) because the voltage limit is not reached

Page 10: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

ISCAD: power electronics generations

10

Gen 1

Gen 2

Gen 3

Page 11: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

power electronics: losses at partial load

advantages of MOSFETs in relevant driving cycles

lower forward voltage at partial load (𝑅𝐷𝐷,(𝑜𝑜)𝐼1 instead 𝑉𝐹)

further optimization potential for MOSFET inverter

11

𝑃𝐿 ↓ ↓ 𝐿𝐿𝐿𝐿𝐿𝐿

Page 12: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

DC wiring

larger cross-sections for higher currents short distances for light-weight, aluminum instead of copper

300 hp example (5 kA)

• distance: 1 meter • material cost: < 5 € • conductor mass: < 5 kg

large contact surface

flexible coax conductors using metal braid

• compact design • perfect shielding of electromagnetic fields

12

Page 13: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

top class efficiency

13

Evaluation of Machine and Inverter Losses ISCAD Improves Efficiency by 20% to 25%

𝑃𝐿 ↓

Time (s)

0 200 400 600 800 1000 1200V

eloc

ity (k

m/h

)0

30

60

90

120

Time (s)

0 200 400 600 800 1000 1200 1400 1600 1800

Velo

city

(km

/h)

0

35

70

105

140

NEDC

WLTC

Page 14: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

top class efficiency

14

Page 15: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

numerous additional advantages

MOTOR

extremely cost-efficient

no copper, no magnets

extremely robust

ISCAD - 48V Traction Drive

15

BATTERY

drop out of single battery cells does not result in large capacity reduction

simplified BMS

simplified CID

increased available capacity and lifetime (against higher voltages)

POWER ELECTRONICS

drop out of single half-bridges does not result in large power reduction

power electronics and electrical machine are perfectly integrable

high switching frequency

improved EMI characteristics

common cooling with electrical motor

SYSTEM

electrically intrinsic safe system

effort for high-voltage training of employees (R&D, production, maintenance, etc.) is avoided

12V-supply is simple and very cost-efficient (low voltage DC/DC-converter)

scalability of the system is very simple (same power electronics modules for all different power levels)

best-in-class availability

very low system costs

Page 16: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

Conventional BEVs ISCAD – 48V Drive

16

NO DANGER LOW

VOLTAGE

SUITABLE FOR ANYBODY

Page 17: ISCAD - 48V Traction Drive: Advantages and Challenges...ISCAD - 48V Traction Drive - Advantages and Challenges Dieter Gerling . Universität der Bundeswehr München

ISCAD - 48V Traction Drive

main challenges

contacts with low ohmic resistance

conductive high power charging

main advantages

electrically intrinsic safe system

extremely cost-efficient

no material supply issues (e.g. copper, rare-earth magnets)

best-in-class system availability

perfect scalability

extremely high partial-load efficiency -> reduction of battery capacity (same range)

unsurpassed acceleration power

no high-voltage training of employees 17