high voltage dc fuse protection for hybrid electric vehicles · high voltage dc fuse protection for...

© 2015 Eaton, All Rights Reserved.

High Voltage DC Fuse Protection for Hybrid Electric Vehicles

Saffiya Osman, Field Applications Engineer

Sam Mudge, Product Manager

2 © 2013 Eaton Corporation. All rights reserved. E © 2014 Eaton Corporation. All rights reserved.

Hybrid & Electric Vehicles Today vs. Tomorrow

• More power

• Greater range

• Faster

• Scaleability

• Mass transport (Tram & Bus)

• LGV & HGV

3 © 2015 Eaton, All Rights Reserved.

HEV Fusing development

Project description:

• Safe and effective protection of the electrical

systems such as battery module and cables

within an EV, Drayson world land speed record

for EV (328.6km/h)

Value Proposition:

• Bussmann fuses are suited for even the most

demanding applications such as electric

vehicle technology, they prevent components

from major damage and protect the driver

against fire in the event of a crash

Technical Differentiators:

• Field Application Engineering

• In-house testing capability

• Understanding of critical DC protection


HEV Fuse Applications

5 © 2012 Eaton Corporation. All rights reserved.

Key Considerations for HEV

5

• Typical system requirements

• ~500Vdc (for passenger vehicles); up to 450A

• Growing all the time

• ~750-1000Vdc (truck and bus); up to 600A

• Recent requests >1000Vdc

• Low time constants

• Differences between Industrial fusing to Automotive

• Cyclic load profile – difficult to define, depends on stop/start, nature of journey,

depends on different driver styles

• Ambient temperature profile (low and high)

• Shock and Vibration

• Space and weight – mounting options


Selection Process for HEV

• Rated Voltage

Dimensioning

• Rated Current

Dimensioning

• Fuse Selection Criteria ?


Rated Voltage Dimensioning

• Most HSF fuses currently designed for AC systems therefore HEV requires

additional DC capability testing

• To properly protect any system – fuse voltage rating must be at least equal to

the system voltage

• HEV typically has low time constant, making it more comparable with the

current AC characteristics of the fuse

• Voltage requirement significantly affects the size of the fuse


Rated Current Dimensioning

• Rated Current – RMS current the fuse can carry continuously

without degrading/exceeding temperature rise limits (under well defined

steady-state conditions)

• Many conditions can affect the current carrying capability

• Guidelines for selecting the current rating

• Basic Selection factors

• Influence of Overloads

• Cyclic Loading

• G & B factors


Basic Selection

Ib = In x Kt x Ke x Kv x Kf x Ka x Kb

• Ib = The maximum permissible continous RMS load current

• In = Rated current of a given fuse

• Kt = Ambient temperature correction factor

• Ke = Thermal connection factor

• Kv = Cooling air correction factor

• Kf = Frequency correction factor

• Ka = Correction of high altitude (above 2000m)

• Kb = Fuse load constant


Cyclic loading and Overloads

• Cyclic loading and Overloads lead to premature fuse fatigue

which can later cause nuisance tripping

• Current variations of sufficient size and duration to change the

temperature of the fuse elements in such a way that the very

sensitive restrictions (necks) will fatigue


…Cyclic Loading and Overloads

• Regular or irregular variations of the load current

• Causes the temperature of the fuse elements to fluctuate

• Heavy thermal cyclic loading leads to mechanical stress premature

aging/fatigue

• SOLUTION – Reduce ΔT of the fuse by selecting a higher rated fuse

• Use “G-factor” to apply a safety margin in the fuse selection

• 1.6 in general applications

• 1.3 in EV applications – irregular but not generally high overloads (average

temperature of elements)

• In > Irms * G

Drive cycles influence fuse selection Needs early consideration


Fuse Selection

North

American

BS88 Ferrule Square Body

Requirements

• Current Voltage capability

• Current de-rating

• Physical size and type

Modifications

• Internal element modifications time-current characteristics verified on test

• Voltage capability verified on test (450Vdc-500Vdc not common for HSF industrial applications)

DIN 43653 BS88 Blade DIN 43620

Flush End

French

End Tag Options (square body)


Challenges in EV Applications

• HSF product range designed for industrial applications

• Application:

• Very high and very low ambient temperatures

• Application: -40oC +105oC

• Test: Thermal load and thermal shock – 500+ cycles!

• Testing vs Real life applications

• Cyclic load profile – difficult to define

• Small cables

• Space constraint

• High shock and vibration tolerance

EV Applications push standard industrial fuses to design limit


Automotive Standards and Qualification

• No global standards for Electric Vehicles: • AECQ200

• JASO D622 – Japan

• SAE J2781

• ISO 8820-1

• ISO 8820-8

• Solutions are fully catered to accommodate each OEM requirements

• In-house testing capability within Eaton • DC capability

• Shock and vibration

• Cyclic loading

Early awareness of OEM test spec. is essential for fuse selection

© 2015 Eaton, All Rights Reserved. 15

Why choose Eaton….

• Over 100 years experience in fuse protection

• Global manufacturing and distribution for world class lead time

• Global accreditations – IEC, DIN, BS, UL, CSA, CCC….

• Product portfolio – most comprehensive in the world

• Worldwide Field Application Engineers to assist in fuse selection and

application advice, also providing complete technical comparisons

© 2015 Eaton, All Rights Reserved. 16

CONTACT:

Sam Mudge, Product Manager

[email protected]

Saffiya Osman, Field Application Engineer

[email protected]

mailto:[email protected]

mailto:[email protected]

high voltage dc fuse protection for hybrid electric vehicles · high voltage dc fuse protection for...

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