Isolated DC-DC converters are a key component to many power conversion applications such as EV Chargers, Industrial Power Supplies, Energy Storage Systems, Welding/Induction Heating, and many others. There are many different topologies utilized to create isolated DC-DC converters; however, for applications greater than 10 kW, applications are typically limited to Dual Active Bridge, Phase Shifted Full-Bridge, LLC, CLLC, and other resonant topologies. These converters utilize a full-bridge of active devices on the primary side and either a diode rectifier (power uni-directional power configuration) or another full-bridge of active devices (bi-directional power configuration) on the secondary side. The graphic below shows how these topologies share a common architecture but differ in the high frequency transformer stage.
Power systems greater than 10 kW can take advantage of the many benefits that power modules can offer. These benefits include high thermal conductivity, built-in isolation to a heatsink, optimized PCB layouts, power scalability, simplified system design, and reduced manufacturing complexity. This directly translates to improved performance while simultaneously reducing time to market and manufacturing costs.
Wolfspeed offers a wide selection of power module products that span from 5 kW to 100’s of kW in capability. The diagram below illustrates how Wolfspeed’s various power modules fit into the power spectrum.
For high power applications, dual half-bridge modules can be utilized together to form full-bridges, enabling much higher current than a full-bridge in a single module footprint. The benefit of this approach is scalability, even within a product family the current and power can be adjusted depending on the application.
The primary downside of utilizing multiple half-bridge modules to form full-bridges is increased system volume. The newly introduced, dedicated full-bridge modules in the Wolfspeed WolfPACK family now offer an extremely power dense full-bridge solution, that is also readily scaled to higher power levels with other products within the WolfPACK family. The benefits of active full-bridges to isolated DC-DC converters can be achieved in an extremely simple and dense solution, requiring only a single full-bridge module for both input and output, halving the number of modules required in a half-bridge solution. Yet, the power scalability still exists within the platform. The new CBB021M12FM3 and CBB032M12FM3 are 21 mΩ and 32 mΩ full-bridge modules. These modules have current capability of 39 A (CBB032M12FM3) and 50 A (CBB012M12FM3) that are well suited for DC-DC converters in the 15-35 kW range. This power level is a “sweet spot” for building scalable power systems based on a building block approach, as there is significantly wider selection of other system components available at this power level such as inductors, transformers, sensors, etc.
To support the design-in process, Wolfspeed has collaborated with several gate driver partners. The gate driver designs are available with differing design goals in mind, ranging from simple and cost effective all the way to feature-rich configurable designs. The gate drivers are also designed to be plug-and-play with evaluation boards specifically tailored for the new full-bridge modules.
The dynamic evaluation kit (KIT-CRD-CIL12N-FMB) is designed to enable you to quickly evaluate the dynamic performance of the module. It includes DC-Link capacitors, high-frequency current shunt, probe points, and is plug-and-play with partner gate drivers.
Interested in understanding how these new full-bridge modules, along with Wolfspeed’s existing module portfolio can help address your needs? Visit our product page for more details along with key supporting items such as SpeedFit™ design simulation, PLECS models, application notes, reference designs, and evaluation kits.
