EBV presents Infineon advanced E/E architecture and 48V boardnet
Sustainability, reducing the CO2 emission, recuperation of kinetic energy is a must have. Automated driving increases the power demand for actuation and diagnosis capabilities. These are just some of the challenges for the next design of cars. With dual power supply 12/48V it seems to be a perfect match between sustainability and providing the right power needed.
Classic centralized power distribution schemes can no longer fulfill these requirements. Smart, decentralized power distribution architectures, however, provide an alternative approach that allows engineers to address these key design criteria by using the latest semiconductor technologies to replace conventional relays and fuses. The various protection and diagnostic features of a smart switches are essential for modern power distribution systems.
As a new voltage domain for vehicles, today’s selection of 48V micro-hybrid components is limited. But this doesn’t change the fact that you need cost-effective, high performance and well-aligned electrification solutions for your applications. Infineon offers an entire system of chipset solutions, from voltage regulators and transceivers to sensors, microcontrollers and smart power drivers. They’re also pleased to support you with our 48V micro-hybrid system demonstrators for inverters and DC/DC
Discover here the applications and Infineon Solutions that are helping engineers to effectively solve these challenges.
48V boardnet & functions
An additional CO2 saving can be achieved by adding an electrical motor to support the various operational states of a car and which allows a recuperation of energy into a battery. This concept led to the development of different types of hybrid electrical vehicles, such as plug-in hybrid electric vehicles, full hybrid electric vehicles and mild hybrid electric vehicles (MHEV) Depending on the type of hybridization a CO2 saving of up to 50% can be reached.
From the commercial point of view the MHEV is the most economical type where invest per saved gram of CO2 is the lowest. The additional applications in a MHEV typically require power compared to applications in a car with just an ICE. To enable and supply these applications used in a MHEV, a higher voltage level is required. As a compromise (trade off) between safety specifications and the power needed an additional power network at 48V was established. In 2016 the first production car with a 48V system architecture entered the market and more and more OEM offer mild hybrid models with a 48V architecture.
Benefits of 48V:
- The main benefit of a 48V power network with its typical applications is the reduction of the CO2 output
- This is realized mainly by the recuperation of energy but also driving support by the starter generator is a benefit of the 48V network.
- New comfort features which need a higher power density are as well an advantage of the second power network in a MHEV.
- Further auxiliary applications which consume high power can be moved from the 12V network to the 48V side. This allows realizing of an even more stable 12V power network.
48V Architecture from P0 to P4 generation
The Audi SQ7 was the first car on the road with a 48V power network. It was not implemented to provide hybrid functionality, it was just invented to enable performance and comfort features which need for a short time a high energy input. This high power demand can be provided by a 48V lithium ion battery. All other applications consuming electrical energy are supplied by the 12V net. Even the generator is supplying the 12V net and the power for the 48V is provided via a DC/DC converter from the 12V power net.
- Clear focus on electrified comfort features and increased performance such as e-turbo and roll stabilization.
- Applications which could be hardly driven in a 12V environment can now be realized
The SQ7 is the first and the last of his kind. In a 48V subnet the essential role has the Starter Generator (SG) and therefore can also be called the heart of a MHEV. With the starter generator two essential applications are enabled which make the combustion engine driven car to a mild hybrid electric vehicle. For driving (limited) the SG can support or drive the car with up to 15kW of power. Energy recuperation is the second key feature of a MHEV. Due to the more powerful 48V subnet more energy can be regained and transferred into the battery. In a simplified approach, the generations P0-P2 differ only if there is a belt driven SG or an integrated SG used and where the integrated SG is mounted. Is it belt driven (P0)? Merged into the crankshaft (P1), into the transmission (P2) or is it even transmission mounted (P3).
- Overall savings: 6 to 8 % CO2
- Comfort features and increased performance
- Starter generator (smooth starting and boosting function)
- (- 48V battery (Li-Ion / super-cap) incl. BMS & main switch)
- Bidirectional DC/DC converter, possible complementary supply of the two power networks
More and more applications consuming higher power are moved to the 48V subnet. Heater or auxiliary drives such as water pump or engine cooling fan can be supplied by the 48V net. Generation P4 vehicles have an electric axle and AWD/4WD (all-wheel) on demand is feasible.
- Overall savings: up to 20 % CO2
- Increased boosting performance + recuperation power
- Beltless starter generator
- Electric air charger/compressor (eAC)
- Sailing & predictive driving (ICE off @ city traffic, parking, coasting)
- Low point shifting
- Torque vectoring (without differential)