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

With the global awareness of environmental protection rising, the global automotive industry is slowly entering the era of electrification to reduce carbon emissions. The vehicle system is mainly composed of three electric components: battery, electric drive, and electronic control. The battery system is the power source of the vehicle, and the OBC system that charges the battery is even more important. A highly safe and efficient OBC system is bound to be needed by the entire industry.

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

1. Stellar-E (SR5E1)

In the era of information explosion, the protection of automobile information is becoming increasingly important. The Stellar series chips developed by ST specifically for automotive use have a high level of information protection capabilities.

The requirements for electric vehicles include powerful hardware devices to ensure efficient power conversion and performance with excellent safety and security. The ability to receive regular wireless software updates is at the core of functional enhancements and guarantees critical safety and security updates throughout the vehicle lifecycle. Improve the user experience through enhanced range and performance and the latest safety updates. The key to the excellent performance of electric vehicles lies in the components of the car and how they combine advanced digitalization with efficiency and innovation. The OBC system designed using the Stellar-E series can bring 22KW of energy to charge the vehicle battery, while also combining 3KW of DC power for on-board use.

This article will discuss in depth the advantages of Stellar-E chips, the design of the OBC system, and future prospects.

2. Stellar-E Features

• AEC-Q100 automotive qualified

•SR5 high performance analog MCU: digital and analog high frequency control technology required by new wide bandgap (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

2. 22KW OBC System Combo 3KW DCDC

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

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

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

• Faster control loops for optimal utilization of SiC/GaN

• High Resolution Timer (HRTIM) for SiC/GaN

•Supports 3KWDC-DC peak current mode control (PCMC)

•Supports two CLLC control combinations:

(1).PFM+phase shift control

(2). Peak current mode control (PCMC)

• CRM controlled PFC

• With bidirectional power supply function, can be charged and discharged

•Fully supports 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

3. Rapid Control Prototyping

•Speed ​​up the development process and shorten the development time

• 3ph PFC (800V) running with first STAR-E MCU sample within 2 months using MBD method

• Prototype development, reference design, solution development

• Provide a complete support package to shorten the 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 onboard charger (OBC), you can charge the battery from an AC mains outlet at home or at a private or public charging station. From 3.6 kW single-phase to 22 kW three-phase high-power converters, with the use of third-generation semiconductors SiC and GaN, today's OBCs must have the highest efficiency and reliability to ensure fast charging and meet limited space and weight requirements. In the future of high-safety power supply design, the Stellar-E series can meet the charging design needs of its electric vehicles.

►Scenario application diagram

► Display board photos

►Solution Block Diagram

►Core technology advantages

The requirements for electric vehicles include powerful hardware devices to ensure efficient power conversion and performance with excellent safety and security.

The ability to receive regular over-the-air software updates is central to the functionality enhancements and ensures critical safety and security updates throughout the vehicle lifecycle.

Improve the user experience with enhanced range and performance, and the latest safety updates.

The key to an electric car’s superior performance lies in the vehicle’s components and how they combine advanced digitalization with efficiency and innovation.

►Solution Specifications

1. CRM controlled single-phase/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