48V Regional Architecture: The Future of Electric Vehicles

After Tesla began using the 48V system, new trends have emerged in the electrical field and communication architecture. The 48V regional architecture is becoming a key technology to improve the performance and efficiency of electric vehicles.

Tesla's solution still retains the traditional 48V battery, and the power module can play an important role in the entire power network. Regarding how to design this aspect, Vicor introduced how the 48V regional architecture can optimize the battery system of battery electric vehicles (BEV), which is a more valuable and forward-looking solution.

Of course, we also see that the switch between 12V and 48V solutions has a great impact on the low-voltage electrical architecture, so at present, we still focus on forward-looking thinking.

Part 1

Challenges of Electric Vehicle Systems

The main challenges facing electric vehicle systems include compatibility with roadside chargers, system complexity handling, weight minimization, and power dissipation. These challenges become more complex as pure electric loads gradually transition from 12V to 48V, including motor loads, non-motor loads (such as computing platforms for smart cars, heated windshields, etc.) and functional safety loads (such as electric power steering, smart electronic brakes, etc.).

● System complexity: As electric vehicles increase in functionality, electrical systems become more complex, and traditional centralized architectures are unable to meet the demands.

● Compatibility issues: There are compatibility issues between charging stations with different voltage standards (400V and 800V), which leads to charging inconvenience.

● Weight and heat dissipation: Electric vehicles need to reduce weight as much as possible and dissipate heat effectively to improve driving range and system efficiency.

From this picture, we can see that it mainly includes 12V and 48V loads. The low-voltage load of the whole vehicle is transmitted through 48V, and the 12V electrical load is converted through 48V.

The shift from centralized to regionalized electrical and electronic (E/E) architecture is in response to growing load demands.

The regional E/E architecture is equipped with a high-performance computing unit and connected via CAN bus and automotive Ethernet, enabling more efficient load management and power distribution.

The 48V PDN solves the incompatibility issues between 400V and 800V charging infrastructure by integrating the charger and 48V power delivery network into the battery pack. This integration not only reduces heat, cost and weight, but also improves the overall efficiency of the system.

Part 2

Design

Overall, a 48V regional PDN using high-density power modules brings multiple benefits, including reducing system weight, size, and complexity, providing flexibility and scalability, accelerating time to market, simplifying the power delivery network, and reducing the weight and cost of the wiring harness.

By integrating 48V conversion during battery system assembly, vehicle assembly time can be reduced at the factory and costs can be saved through integration.

The 48V PDN solution includes the use of components such as the BCM6135 and PRM3735, which provide high transient response and efficiency, as well as stable regulated output voltage. The application of these power components enables 48V and 12V loads to be managed and distributed more efficiently.

To further reduce the size and weight of PDNs, the concept of using virtual batteries has been proposed to eliminate or minimize the need for batteries in an innovative way.

To enable 800V BEVs to charge at 400V charging stations, chargers based on the Vicor NBM9280 parallel solution can maintain high performance even at a coolant temperature of 50°C.

High-density power modules, such as Vicor’s NBM9280 and BCM6135, can further improve system efficiency and response speed. These modules have the following advantages:

● High efficiency: The peak efficiency of BCM6135 can reach 97.3% at 800V input voltage.

● High transient response: Can maintain stable output when load current changes rapidly.

● Modular design: Each power module can be easily connected in parallel or expanded to meet different power requirements, ranging from 1kW to 20kW.

Judging from the results, by introducing smaller power modules, the distributed architecture can achieve a lighter effect compared to the original centralized electrical architecture.

In order to better manage and distribute power, the automotive electrical architecture has evolved from the past distributed architecture to the current domain-centralized architecture and gradually to the future regional architecture. The regional architecture achieves more efficient power management and lower system complexity through high-performance computing units and regional control units (ZCU).

summary