Developing power and data networks in emerging vehicles
When we talk about emerging vehicles we are typically talking about the electrification of the drivetrain in traditional vehicles, or the introduction of entirely new vehicles. With hybrid technology also advancing, some emerging vehicles will continue to leverage internal combustion.
In all cases, total or partial electrification of the drivetrain comes with new requirements. Transferring energy from a rotating electric motor is entirely different to harnessing the power of a reciprocating internal combustion engine. In most cases, control is simpler as there are fewer moving parts, but the focus is also now on the efficient and safe application of high voltages.
If we couple this with the overarching trend for more data, we see that the power and data network architectures in both traditional and emerging vehicles are changing. Some new vehicles may look and feel like their older counterparts, but beneath the outer layer they are entirely unrecognizable.
Moving data centers
Leading voices in the automotive industry confirm that the amount of data generated by a modern vehicle can reach 10s of Gbytes per hour. That equates to hundreds of Tbytes in a year. It is little wonder that cars are now being referred to as data centers on wheels.
To combat this increased digital traffic in the vehicle, manufacturers are adopting zonal architectures. A zonal approach to vehicle design changes the way functions are grouped. In a traditional architecture, similar functions would be on the same wired network, irrespective of where they are in the vehicle. Wiring looms can reach tens if not hundreds of kilometers. The weight of the loom has increased so much that it is now often the second heaviest component in an ICE vehicle, after the engine.
The weight, cost, and complexity of wiring looms is a growing problem for manufacturers. Moving to a zonal architecture reduces the need to run wires long distances around a vehicle chassis. Instead, local processors manage areas of the vehicle and report back to a central computer that has overall control.
Power distribution
In an electric drivetrain the major components are the power cabling, the battery, the traction motor(s), and the energy converters. The battery in an electric vehicle can range from around 65 V in an e-scooter up to 800 V or more in a family saloon or truck.
The traction motors and inverters will vary in a similar way, depending on the vehicle. Selecting the right solution will depend on the vehicle, but it will also be influenced by the commercial considerations. More efficient inverters may require higher quality components but deliver a better user experience in terms of range and reliability.
As electrification takes hold, the need to deliver power to more electronic control units (ECUs) will also increase. The demand may be to power more ECUs or deliver more power to the same number of ECUs. In each case, power distribution comes with considerations around wiring and connections.
Making the right connections in data and power
In some applications where space is limited, such as in electric mobility devices or smaller EVs, OEMs will need to combine power and data in a single connector. This can present further design challenges. The Compactus Sealed Hybrid connectors from Molex is a robust, IP69k-rated solution. The Compactus system is rugged enough for harsh environments with high levels of vibration, yet still extremely compact thanks to Molex’s advancements in miniaturization.
OEMs looking to eliminate some of the tooling costs associated with design flexibility might benefit from the stAK50h unsealed stackable connection system from Molex. The stAK50h system is USCAR compliant and meets the industry-standard automotive footprint for 0.50mm, 1.20mm and 2.80mm terminal sizes.
More mid- to high-end vehicles now include autonomous features enabled by technologies such as high-resolution cameras, radar, and LiDAR. The High-Speed FAKRA Mini (HFM) coaxial cable is specified for signals up to 20 Gbps and forms part of the Molex portfolio of high-speed networking cable solutions for transportation.
Read more about the range of solutions Molex offers for zonal vehicle architectures.
The stAK50h family of unsealed stackable connectors from Molex
Power management in electric vehicles
Controlling the flow of power in modern vehicle architectures now involves multiple voltage domains. The use of 48 V networks for the electrification of mechanical functions is increasing in internal combustion engine vehicles and mild/hybrid/battery electric vehicles.
The complementary trend is to use solid state switches in place of larger and less reliable electromechanical relays. Controlling voltage domains now typically involves using power MOSFETs as high-side switches.
Switching MOSFETs in a high-side configuration requires drivers and controllers. While this adds to the cost and complexity over electromechanical solutions, it is a prime example of how the additional cost is far outweighed by the increased value solid-state switching brings.
The VNF1048F from STMicroelectronics is the first product in the new STi2Fuse family of smart switches for harness protection. Other devices in the family will comprise single-, dual-, and quad-channel smart electronic digitally resettable fuses. The VNF1048F, available now, is a gate controller, able to switch high-side power MOSFETs to control 12 V, 24 V, and 48 V rails, digitally.
Data transport in electric vehicles
In-vehicle networking is evolving, as Ethernet proves itself capable of providing the high bandwidth and robustness needed for advanced systems such as LiDAR and cameras. With CAN still very much a favorite, FlexRay is also the well-established choice for advanced in-vehicle fault-tolerant communications.
For less demanding data communications, such as sensors and actuators in comfort functions, LIN (Local Interconnect Network) still has value. CXPI (Clock eXtension Peripheral Interface) was conceived to succeed LIN, by reducing the number of devices needed for the clock part of the network. The CXPI transceivers offered by Infineon include in the S6BT112A01 and S6BT112A02 integrated transceivers. The transceivers combine a CXPI data link controller and CXPI bus line. These integrated solutions include high surge protection, allowing them to be connected the vehicle battery directly.
Combining power and data appeals to system architects in OEMs developing new vehicles. Achieving this can be challenging, but the TLE9278BQX V33 from Infineon is one example. This highly integrated device combines four CAN transceivers that are compliant with the CAN Flexible Data-rate (FD), alongside a switched-mode power supply (SMPS) with integrated switches for implementing DC-DC buck/boost power switching. Infineon has managed to combine these features in a package measuring just 7mm by 7mm.
The TLE9278BQX V33 can be used in gateways, body control modules, chassis control, and in driver assistance applications. The SMPS buck regulator can provide 3.3V at up to 750mA. The device is controlled over a SPI interface. A low-power mode means the device can be used in always-on applications that are permanently powered by the vehicle’s battery.
For functions like LiDAR and cameras with high bandwidth demands, Ethernet’s popularity continues to grow. The SJA1110 family of software- and pin-compatible Ethernet switches from NXP comprises four devices. The SJA1110 family is aimed at automotive applications including ADAS, infotainment, service-oriented gateways, digital clusters, and zonal architectures.
All four devices integrate 100BASE-T1 and 100BASE-TX PHYs and support time-sensitive networking (TSN) standards. The Ethernet switches also include best-in-class packet inspection and DoS prevention capabilities. Advanced secure boot and functional safety features are also included.
The software defined vehicle
More automotive OEMs are developing advanced vehicles that harness electrification. The benefits that come with moving away from fossil fuels and internal combustion create opportunities to rewrite the playbook.
We will see increasing diversity in mobility, differentiated by advanced features such as autonomous driving. The complexity will move away from controlling mechanical systems, toward leveraging the information afforded by data. Power distribution and management, and data networking are emerging as the platforms for innovation.
Automotive innovation will result in the prevalence of software-defined vehicles that provide greater customization, with the extensibility and flexibility that offers. Avnet and its supplier partners are at the forefront of this exciting period in automotive history.
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