High Voltage DC Fuse Protection for Hybrid Electric Vehicles

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1 High Voltage DC Fuse Protection for Hybrid Electric Vehicles Saffiya Osman, Field Applications Engineer Sam Mudge, Product Manager

2 Hybrid & Electric Vehicles Today vs. Tomorrow More power Greater range Faster Scaleability Mass transport (Tram & Bus) LGV & HGV Eaton Corporation. E All rights reserved. 2

3 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 3

4 HEV Fuse Applications 4

5 Key Considerations for HEV Typical system requirements ~500Vdc (for passenger vehicles); up to 450A Growing all the time ~ Vdc (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 2012 Eaton Corporation. All rights reserved. 5 5

6 Selection Process for HEV Rated Voltage Dimensioning Rated Current Dimensioning Fuse Selection Criteria? 6

7 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 7

8 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 8

9 Basic Selection I b = I n x K t x K e x K v x K f x K a x K b I b = The maximum permissible continous RMS load current I n = Rated current of a given fuse K t = Ambient temperature correction factor K e = Thermal connection factor K v = Cooling air correction factor K f = Frequency correction factor K a = Correction of high altitude (above 2000m) K b = Fuse load constant 9

10 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 10

11 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 11

12 Fuse Selection Requirements Current Voltage capability Current de-rating Physical size and type BS88 North Ferrule Square Body American End Tag Options (square body) DIN BS88 Blade DIN Flush End French Modifications Internal element modifications time-current characteristics verified on test Voltage capability verified on test (450Vdc-500Vdc not common for HSF industrial applications) 12

13 Challenges in EV Applications HSF product range designed for industrial applications Application: Very high and very low ambient temperatures Application: -40 o C +105 o C 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 13

14 Automotive Standards and Qualification No global standards for Electric Vehicles: AECQ200 JASO D622 Japan SAE J2781 ISO ISO 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 14

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 15

16 CONTACT: Sam Mudge, Product Manager Saffiya Osman, Field Application Engineer 16

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