The reference design has silicon carbide (SiC) technology and high-frequency operation for optimal power management and energy regeneration.
High-power bidirectional DC-DC power converters, particularly those utilising a dual active bridge (DAB) topology, play a crucial role in modern power systems. These converters enable efficient energy transfer between different voltage levels, making them essential for applications requiring charging and discharging capabilities, such as electric vehicles (EVs), renewable energy storage systems, and industrial power supplies. The DAB topology offers significant advantages, including high efficiency, compact size, and the ability to operate at high frequencies, reducing passive components’ size and cost. Additionally, its bidirectional nature allows for seamless power flow control in both directions, supporting energy regeneration and optimised power management.
This reference design, UM3198 by ST Microelectronics, provides a comprehensive solution for a high-power bidirectional DC-DC power converter, utilising a dual active bridge (DAB) topology based on ACEPACK2 SiC power modules. Control of the power converter is managed through the STM32G474 MCU, a mixed-signal digital platform optimised for digital power applications. Integrating the latest generation silicon carbide (SiC) power modules and high-frequency operation (100 kHz) ensures superior performance and design efficiency. Soft switching is achieved through modulation techniques that adjust according to load and voltage variations, improving the converter’s overall performance. The STDES-DABBIDIRP is the main power board, using ACEPACK2 SiC power modules. It includes a full-bridge module (A2F12M12W2-F1) for the high-voltage side and two half-bridge modules (A2H6M12W3-F) for the low-voltage side, along with bulk capacitors, sensing sections, and an auxiliary power supply.
The STDES-DABBIDIRDF driver board controls the full-bridge module with an STGAP2SiCS gate driver. STDES-DABBIDIRDH has two driver boards for the half-bridge modules, and it also uses STGAP2SiCS drivers. The control board, STDES-PFCBIDIRC, uses an STM32G4 microcontroller for communication and programming. Advanced SiC MOSFETs and the DAB topology at a 100 kHz switching frequency achieve nearly 98% efficiency, allowing for smaller, cost-effective passive components. This design is ideal for high-efficiency, reliable applications such as EVs, industrial battery chargers, and other equipment. The bidirectional isolated DC-DC converter features two voltage-sourced full bridge circuits connected via an inductor and high-frequency transformer. Its symmetrical design enables bidirectional power flow, with each bridge operating in a totem pole configuration for efficient energy transfer.
ST Microelectronics has tested this reference design. It comes with a bill of materials (BOM), schematics, assembly drawing, printed circuit board (PCB) layout, and more. The company’s website has additional data about the reference design. To read more about this reference design, click here.
