Demand for reliable circuit protection, high-speed communications, and compact power conversion solutions in e-mobility and transportation systems is growing on a range of platforms, including hybrid and electric vehicles, buses, medium- and heavy-duty on- and off-highway vehicles, and marine platforms . These trends are being driven by a growing emphasis on sustainability and safety as the transportation industry transitions to more autonomous control and electric vehicles (EVs) or hybrid electric vehicles (HEVs). As a result, new vehicle systems are emerging that gradually become more dependent on safe and sustainable vehicle operation.

Author: Jeff Shepard

Demand for reliable circuit protection, high-speed communications, and compact power conversion solutions in e-mobility and transportation systems is growing on a range of platforms, including hybrid and electric vehicles, buses, medium- and heavy-duty on- and off-highway vehicles, and marine platforms . These trends are being driven by a growing emphasis on sustainability and safety as the transportation industry transitions to more autonomous control and electric vehicles (EVs) or hybrid electric vehicles (HEVs). As a result, new vehicle systems are emerging that gradually become more dependent on safe and sustainable vehicle operation.

To ensure safety and reliability, designers of connected, electric and autonomous vehicles require a wide variety of circuit protection and communication and power conversion solutions designed to operate reliably in challenging environments, And certified to meet AEC-Q200, SAE, USCAR and other performance standards.

This article briefly reviews some circuit protection device specifications that designers need to be aware of. It then introduces Bel Fuse’s specific circuit protection, connectivity and power conversion solutions, and studies the application of these products in electric mobility systems.

Electric Vehicle Protection components and Standards

To address the challenges surrounding electric vehicles, designers can take advantage of a range of circuit protection, high-speed communications, and power conversion solutions qualified and certified to automotive-grade standards, including:

・Automotive qualified fuses in cartridge, PC board mount (through hole and surface mount) and offset stud configurations optimized for powertrains and subsystems, plus fuses for auxiliary applications and accessories , such as driver assistance radar systems, brake pump motors, portable chargers, battery systems, infotainment systems, cameras, programmable lighting, and power-assisted steering. In addition, specific applications will • require high surge, fast acting, slow trip and recoverable polymeric positive temperature coefficient (PPTC) insurance.
AEC-Q200 qualified electromagnetic interference (EMI) suppression chokes that filter noise and protect high-speed data signals and provide Differential noise suppression is provided by Automotive Ethernet, Controller Area Network (CAN) bus, FlexRay, and Automotive Universal Serial Bus (USB).
・ Fully shielded RJ45 connector compliant with Society of Automotive Engineers (SAE) USCAR2-6 (System Performance Specification for Automotive Electrical Connectors – 6th Edition), allowing designers to replace the CAN bus with faster and lighter automotive Ethernet to support Growing in-vehicle computing needs for a range of ADAS systems, such as driver assistance cameras and radar-based driver assistance systems, as well as telematics, media converters, and gateways.
・IP67 certified power converters, including automotive-qualified electric and hybrid vehicle battery chargers, feature convection or liquid-cooled implementations with galvanic isolation.

Choosing a Circuit Protection Device

To select the appropriate device, it is important to have a clear understanding of its operating characteristics when specifying circuit protection devices for e-mobility systems. Some basic specs include:

・ Rated voltage: the maximum voltage allowed for safe work
・Rated current: The current that a fuse can carry under normal operating conditions, in amperes (A)
Breaking capacity (also known as breaking rating or short-circuit rating): The maximum current that a fuse can break at its rated voltage without being damaged; the breaking capacity must meet or exceed the expected maximum fault current of the circuit
・ Time Current Curve: Defines whether the fuse is fast or slow (also known as delayed action); fast fuses are used where speed of protection is critical; slow fuses are used where short current surges or overloads occur

I2t: a specification without a test standard

One specification that deserves special attention is the nominal melt rating, I2t (pronounced “I squared T”). This is a measure of the energy required to melt a fuse element, an important fuse characteristic in any application. I2t is expressed as “ampere squared seconds” (A2 seconds). Unfortunately for the designer, neither the UL/CSA 248 nor the IEC127 miniature and miniature fuse standards include a test procedure or test standard for I2t. The industry standard definition of I2t is:

Fusing I2t is measured at 10In using constant direct current (DC), where ln is the rated current of the fuse.

Using 10In can be problematic and does not always give an accurate open time. Especially slow fuses may require multiples higher than 10 times the rated current to get a true I2t value. Because different manufacturers approach this challenge differently, the designer must have a clear understanding of the method used to derive the I2t value for a particular fuse. There is a more detailed discussion of these challenges here: I2t Demystified.

Fast-Blow and Slow-Blow Chip Fuses

Thick-film technology-based surface mount devices are available to designers of automotive navigation systems, lithium-ion (Li-ion) battery management systems (BMS), LED headlights, automotive Power over Ethernet (PoE), PoE+, and liquid crystal displays (LCDs). Benefit from chip mounted fuses such as the 0685P series fast fuses. The 0685P series has high inrush current capability. These AEC-Q200 qualified, UL Listed 1206 size fuses are rated from 2 A to 50 A and voltage (volts) ratings of 50 volts alternating (AC) and 63 volts direct current. The 0685P3000-01 model is rated at 6 A and has a 10In rated I2t of 1.3 A2 seconds.

For designers requiring slow blowing, Bel offers the C1T series 1206 size blade fuses (Figure 1). These products are available in current capacities from 750 milliamps (mA) to 8 A and are rated at 63 volts ac or dc. Model 0685T6000-01 is rated for 6.0 A and 10In rated I2t is 6.0 A2 seconds. The C1T series slow fuses are UL, CSA, and CE listed, with IEC 60127 TUV certification for small fuses.

How to ensure circuit protection, high-speed data and power conversion for e-mobility platforms
Figure 1: Chip fuses like the slow-blow C1T series are used in a variety of automotive applications where a compact form factor is important. (Image credit: Bel Fuse)

Recoverable PPTC Devices

PPTC devices can be used if the design benefits from the very low operating resistance and very high hold current of resettable circuit protection. PPTC is used in applications such as motor and motor circuit protection for power door locks, mirrors, seats, sunroofs and windows, heating ventilation and air conditioning (HVAC) systems and Electronic control unit (ECU) I/O protection. Especially useful.

Bel offers two PPTC device families. Both are AEC-Q compliant, TUV certified to EN/IEC 60738-1-1 and EN/IEC 60730-1, and recognized to UL1434.

The 0ZRS radial leaded PPTC is rated from 500 mA to 10 A, has a maximum voltage of 32 VDC, and has a typical power rating of 0.9 to 7.0 W (Figure 2). For example, the 0ZRS0100FF1E has a trip current of 1.9 A, a hold current of 1.0 A, and a power rating of 1.4 W.
The 0ZCG surface mount PPTC is rated from 100 mA to 3 A, has a maximum voltage of 6 to 60 VDC, and has a typical power rating of 0.8 to 1.3 W. The 0ZCG0110BF2B device of this series is rated for 24 VDC, 1.1 A holding current, 2.2 A tripping current, and 1 W rated power.

How to ensure circuit protection, high-speed data and power conversion for e-mobility platforms
Figure 2: The OZRS radial leaded PPTC is rated at 32 VDC and has a maximum current of 10 A. (Image credit: Bel Fuse)

Inrush current withstand fuse

The 0680L series square 2410 package size surface mount ceramic fuses have high inrush current capability (Table 1). These slow fuses are designed for applications requiring high DC breaking ratings and high DC voltage ratings. They are rated up to 125 volts DC or AC and provide current ratings from 375 mA to 12 A. The 0680L fuse is AEC-Q qualified.

How to ensure circuit protection, high-speed data and power conversion for e-mobility platforms
Table 1: Electrical characteristics of the 0680L series surface mount slow fuses. (Image credit: Bel Fuse)

These slow fuses are typically used for PoE, PoE+, mains and battery charging circuit protection; the 0680L3000-05 is rated at 3 A and 0.81 W, and I2t is rated at 13 A for 2 seconds at 10In.

Fast Electric Vehicle Power Fuse

Designers can employ fast fuses in cartridge and bolt-on configurations to protect high-power batteries and electric vehicle power converters. These fuses are fully compliant with EU Directive 2011/65/EU and Amendment Directive 2015/863. They are designed to meet the reliability requirements of UL 248-1 and JASO D622 and ISO8820-8. Typical applications include:

・Main system insurance
· charging station
・ Energy storage and battery packs
・ Power distribution unit
・ On-board DC-DC converter
・ Brake pump motor
・ Air conditioner compressor motor
・ Electric steering system

They can handle up to 600 A and are rated at 500 to 1000 VDC; the 0ADAC0600-BE is a typical box fuse rated at 600 mA and 600 VDC or VAC, 10In I2t rated at 0.073 A2 seconds.

Electric vehicle time lag fuse

The 0697W series subminiature radial lead time lag fuses are rated at 350 VAC or 72 VDC and 1 A to 6 A in accordance with IEC 60127-3 (Figure 3). These fuses meet AEC-Q quality and Mil-Std 202G environmental standards.

How to ensure circuit protection, high-speed data and power conversion for e-mobility platforms
Figure 3: The 0697W series are AEC-Q qualified radial lead high voltage time-lag fuses. (Image credit: Bel Fuse)

Applications for the 0697W device include ECUs, motors, climate and ventilation controls, plug and cigarette lighter accessories, power sockets and wiring harnesses. For example, 0697W2000-02 is rated for 2 A and 0.63 W, and I2t is rated for 30 A2 seconds at 10In.

Common Mode Choke Coils for High Speed ​​Communication

Designers of automotive infotainment, multimedia, and ADAS systems using Ethernet, CAN, FlexRay, or USB communication buses can use Signal Transformer’s SPDL series of AEC-Q200-qualified ultra-compact common-mode chokes to suppress differential-mode noise (Fig. 4). These compact surface mount device (SMD) chokes are available in four metric sizes (2012, 3216, 3225 and 4532) and 26 different component ratings. The SPDL series has a current rating range of 150 to 400 mA and an impedance range of 90 to 2200 ohms (Ω). The SPDL3225-101-2P-T model is rated at 150 mA, 2200 Ω, and has an inductance of 100 microhenry (μH).

How to ensure circuit protection, high-speed data and power conversion for e-mobility platforms
Figure 4: The SPDL series of ultra-compact SMD common mode chokes can be used for Ethernet, CAN bus, FlexRay or USB communication interfaces. (Image credit: Signal Transformer)

Upgrade to Ethernet

Designers are replacing the CAN bus with Ethernet in an increasing number of e-mobility applications due to its faster transfer rates and lighter cables. The Bel Fuse MagJack Automotive Ethernet Single Port Integrated Connector Module (ICM) integrates an Ethernet magnetic solution into a connector package. This results in a more compact solution and simplifies the task of upgrading existing CAN bus systems with Ethernet signaling and wiring (Figure 5). The MagJack Ethernet ICM has a maximum operating temperature of 100°C and is compatible with SAE/USCAR2-6. These ICMs are approved by Broadcom, Intel and Marvell and are compatible with standard automotive-grade transceivers, further simplifying the transition to Ethernet.

How to ensure circuit protection, high-speed data and power conversion for e-mobility platforms
Figure 5: The MagJack Automotive Ethernet single-port ICM has integrated magnetics to meet the need for a compact solution. (Image credit: Bel Fuse)

An example is the A829-1J1T-KM Automotive Ethernet ICM, which meets all IEEE 802.3 10/100Base-T electrical requirements.

Power Conversion for HEVs and EVs

Bel Power Solutions offers designers a complete range of e-mobility power conversion options, including DC-DC converters, bidirectional DC-DC converters, on-board chargers, auxiliary inverters, and bidirectional inverter chargers with two DC -Inverter charger system integrated with DC down converter. For example, the 22 kilowatt (kW) BCL25-700-8 is a liquid-cooled on-board battery charger for HEVs and EVs on medium- and heavy-duty platforms on and off-highway (Figure 6). Features and specifications of the BCL25-700-8 include:

・Single-phase (190 to 264 VAC) or three-phase (330 to 528 VAC) input
・ Can be connected to AC mains or Electric Vehicle Supply Equipment (EVSE) charging stations (EV Std. IEC 61851-1)
・ 60A constant output current in the range of 250 to 800 VDC
・ Up to four units can be placed in parallel
・ Compliant with IP67 and IP6K9K standards
・ IEC 61851-21-1 and ECE R10.6 certification
・SAE J1772 and CAN interface compliant with SAE J1939
・ Active HVDC interlock monitoring
・ Full load operating temperature -40 to 60℃
・Over temperature, over current and output over voltage protection

How to ensure circuit protection, high-speed data and power conversion for e-mobility platforms
Figure 6: The BCL25-700-8 is a 22 kW on-board liquid-cooled battery charger for HEVs and EVs in medium and heavy duty applications on- and off-highway. (Image credit: Bel Fuse)

Epilogue

Supporting the safety and sustainability requirements of the next generation of connected, electric and increasingly automated vehicles will require a wide variety of circuit protection, communication and power conversion solutions. As shown, designers have easy access to a variety of solutions including automotive-qualified circuit protection devices, AEC-Q200 qualified EMI suppression chokes, SAE/USCAR2-6 qualified fully shielded RJ45 Ethernet network connectors and IP67 certified power converters. These will help HEV and EV designers address many of the current and emerging design challenges that arise as autonomous designs evolve.

The Links:   SKM75GB063D FF450R17ME3