ST Stellar-E SR5E1 22KW OBC combo 3KW DC-DC car charger solution

For the global awareness of environmental protection is on the rise, the global automotive industry is slowly moving into the era of electrification in order to reduce carbon emissions. The whole vehicle system is mainly composed of battery, electric drive and electric control, among which the battery system is the power source of the whole vehicle, and the OBC system for charging the battery is even more important. A highly safe and efficient OBC system is inevitably needed by the whole industry.

I. Stellar-E - an automotive grade processor with high security

1. Stellar-E (SR5E1)

In the era of information explosion, the protection of automotive information is also becoming more and more important. The Stellar series of chips developed by ST specifically for in-vehicle use has a high level of information protection.

The requirements of electric vehicles include robust hardware devices to ensure efficient power conversion and performance with superior security and safety. The ability to receive periodic wireless software updates is at the heart of the feature enhancements and ensures critical safety and security updates throughout the vehicle lifecycle.

Improved user experience through enhanced range and performance and the latest security updates  The key to superior electric vehicle performance lies in the vehicle's components and how they combine advanced digitalization with efficiency and innovation. The OBC system designed using the Stellar-E series brings 22KW of energy to charge the vehicle's battery, while also incorporating 3KW of DC power that can be used on board.

In this article, we will discuss the advantages of Stellar-E chip, the design of OBC system, and the future outlook.

2. Stellar-E features

• -AEC-Q100 automotive certification
• -SR5 high-performance analog mcu: new wide-bandgap-required digital and analog high-frequency control technology (SiC and GaN)
• -Excellent real-time and functional safety performance (ASIL-D)
• -Built-in fast and cost-optimized OTA (over-the-air) reprogramming capability
• -High-speed secure cryptographic service (HSM)
• -Dual-core 2x 32-bit Arm® Cortex®M7 300MHz computing power

3. Stellar-E SR5E1 Processor Block Diagram

II. 22KW OBC System Combo 3KW DCDC

The design of 22KW OBC system is mainly designed by three power supply topologies and the circuit block diagram is shown below.

1. 22KW OBC combo 3KW DC-DC specification

2. 22KW OBC combo 3KW DC-DC Features

-Faster control loop for optimal utilization of SiC/GaN

-High resolution timer (HRTIM) for SiC/GaN

-Supports peak current mode control (PCMC) for 3KW DC-DC

-Support CLLC two control combinations.

(1).PFM + phase shift control

(2). Peak current mode control (PCMC)

-CRM controlled PFC

-With bi-directional power supply function, can be charged and discharged

-Full support for 3.3KW, 6.6KW, 11KW, 22KW power output

-Single-phase/three-phase PFC switching

3. 22KW OBC combo 3KW DC-DC development board

4. 22KW OBC combo 3KW DC-DC main materials

III. Rapid Control Prototyping

• -Speed up the development process and shorten the development time
• -Use MBD method to run 3ph PFC (800V) in 2 months with the first star - e monolithic sample
• -Prototyping, reference design, solution development
• -Provide complete support package to shorten customer system evaluation cycle

IV. Future Outlook

At the heart of any electric (EV) or plug-in hybrid (HEV) vehicle design lies the high voltage (200 to 800 VDC) battery and its associated charging system. Using an On-Board Charger (OBC), you can charge the battery from AC power at home or at a private or public charging station outlet.

From 3.6 kW single-phase to 22 kW three-phase high power converters, in combination with the use of third-generation semiconductors SiC and GaN, OBCs today must have the highest efficiency and reliability to ensure fast charging and meet limited space and weight requirements. For future high-security power supply designs, the Stellar-E series can meet the charging design needs of their electric vehicles.

►Scene Application Diagram

►Display board photo

►Solution cube diagram

►Core Technology Advantage

• Electric vehicle requirements include robust hardware devices to ensure efficient power conversion and performance with superior security and safety.
• The ability to receive periodic wireless software updates is at the heart of the feature enhancements and ensures critical safety and security updates throughout the vehicle lifecycle.
• Improved user experience through enhanced range and performance and the latest security updates.   
• The key to superior electric vehicle performance lies in the vehicle's components and how they combine advanced digitalization with efficiency and innovation.

► Solution Specifications

• 1. CRM controlled single/three-phase bridgeless totem pole PFC Input: 304Vac-456Vac Output: 450Vdc-900Vdc 
• 2. 22KW OBC Input: 450Vdc-900Vdc Output: 36A Idc MAx.
• 3. 3KW DC-DC Input: 800Vdc /3.75A Idc Output: 14Vdc / 215A Idc 215A Idc