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Case Study
Accelerating Industrial E-mobility
Article
Stercom is making durable, scalable OBCs possible with Wolfspeed SiC
More EV users are looking to gain the most of their batteries by leveraging the expanding charging networks around them – either to power their home, a local grid, another vehicle, or receive power from any of these loads via a bi-directional charger. This concept, aptly named Vehicle-to-Everything (V2X), is one way Stercom is enabling more accessible and efficient charging technologies with Wolfspeed Silicon Carbide.
Together, Stercom and Wolfspeed are taking the universal grid compatibility first introduced via V2X applications for passenger vehicles, and scaling them to ensure that high-power EVs like off-highway heavy duty vehicles, commercial trucks and marine applications can benefit from (and contribute to) regenerative energy. Stercom is proud to shape the way that industrial vehicles – all major emissions contributors – can remain operational for longer periods of time, while reducing their collective carbon footprint.
Challenge:
- Enable bi-directional power flow without compromising on efficiency or charging times
- Deliver a highly durable system capable of operating in demanding environments
- Must be truly scalable and support nearly all grid-voltages and configurations worldwide
Solution:
- A joint technical partnership that began in 2021 and accelerated with Stercom’s adoption of Wolfspeed Gen 4 technology in their next-gen OBC
Innovation:
- A 22-kW onboard charger that’s capable of AC charging in < 3 hours
- Low stray inductance and highly compact 1200-V Gen 4 WolfPACK modules ensured a simpler system design, ideal for parallel connecting up to 8 Stercom OBCs
- 97% OBC efficiency enabled by modules’ low conduction and switching loss performance
An “all-in-one” OBC that makes no compromises
Stercom’s vision to create a 22-kW OBC that had universal grid compatibility (UGC) and optional adaptive charging for all types of high-voltage batteries came quickly on the heels of several years of global investment in fast charging systems. With CAN interfaces and diagnostics, Stercom’s design would achieve seamless integration into most global charging standards and networks. But enabling greater efficiency and shorter charge times in industrial vehicles was another priority, and one that couldn’t be compromised.
It's well understood that silicon carbide (SiC) switches have much better reverse polarity operation than IGBTs, making SiC a natural contender for Stercom’s bidirectional design. But given the long-haul vehicles that the systems would be deployed in, efficiency and durability was a must-have. Enter Wolfspeed’s Gen 4 1200-V WolfPACK™ power modules:
A system built to last
What followed a multi-year partnership built on both company’s technical prowess was two versions of a 22 kW V2X OBC: a 550 V / 70-A option, and its 950-V / 40-A variant. Both designs achieve an excellent 97% efficiency by leveraging 1200-V WolfPACK Modules. The AC-DC portion utilized CHB011M12GM4T’s for 3-level conversion which dramatically reduces dynamic losses, leading to significant magnetics shrink as well as cost down. The isolated DC-DC stage utilizes CBB011M12GM4T’s to enable high-frequency conversion with a small isolation transformer. The ISO-26262 functional safety compliant OBCs come with the added confidence that they’ll operate any altitude, thanks to Wolfspeed’s improved cosmic ray immunity. Safety and durability is further bolstered by the systems’ ISO 16740-4 compliance, a global standard that evaluates road vehicles for climatic loads.
“When our partnership first started, we believed Wolfspeed could deliver on the efficiency that is tablestakes for OBCs. When we moved further through the development of our next gen OBC, we were pleasantly surprised by the thermal behavior and stability of the Gen 4 WolfPACK module technology. It is bar-none.”
Bernd HornHead of Sales, Stercom
The power of partnership
As the creator of the world’s most advanced silicon carbide semiconductor technology, Wolfspeed provides hands-on support throughout the design process to help customers maximize the benefits of silicon carbide. This philosophy guides Wolfspeed’s partnerships with innovators in the marketplace and enables the world’s most disruptive technologies.
“Stercom’s creative vision for prioritizing maximum adaptability in EV charging applications is not only impressive – it’s essential for a sustainable future. Our pursuit of undisputed technology leadership was also essential as we jointly navigated the technical hurdles in ensuring their system’s performance was never compromised. I’m very pleased with the outcome of this partnership.”
Guy MoxeyVice President and General Manager for Industrial and Energy, Wolfspeed
About Stercom Power Solutions, GmbH
Stercom was founded in 2014 with the vision of helping to shape a livable and ecological future through new ideas and innovations. Efficient and safe energy storage and optimized charging technology are our contribution to ecological progress.
Stercom’s team of recognized experts attaches great importance to looking after you from conception through implementation to integration and certification and to developing the best possible technology for your challenge.
For more information, visit www.stercom.de
