Power modules: driving efficiency in inverter solutions

Their common ground of engineering excellence and performance is Bosch's silicon carbide (SiC) semiconductor technology as well as extensive manufacturing experience: Bosch has already sold more than 14 million power modules worldwide since 2011 and is the first chip manufacturer to go into series production with SiC semiconductors in a vehicle inverter – manufactured using the trench-etch process and making Bosch a leading expert in SiC power devices.

The different DSL versions are designed for high-voltage applications like on-board chargers, DC/DC converters, eBDU, and inverters. Their single switch design gives system manufacturers great implementation flexibility within their hardware and scalability across various models. The power module can, for example, be used in two-wheelers with very limited space, giving engineers the maximum freedom to design the best architectural set-up. It comes in voltage classes of 750 V or 1,200 V to cover a broad range of vehicle types. Equipped with Bosch’s second generation dual-channel SiC trench gate technology including improved high temperature RDS(on), switching behavior, and internal gate resistance RG,INT, the DSL can cover all state-of-the-art e-mobility applications that need to be individually designed on electrical component level.

Vehicle production must be flexible and lean to maximize efficiency. Easy handling and installation of components is particularly important for small quantities, customized products or when specific assembly line requirements must be met. Also, in some use cases including performance or prototype car production, fast optimization is essential. The CSL, fully designed by Bosch, specifically addresses the need for easy implementation by manufacturers or Tier1 suppliers. However, the CSL is just as suitable for mass production of general-purpose vehicles.

The PM6.1 is the newest member of the power module portfolio. It is fully designed and produced by Bosch following the local-for-local strategy and addressing the special requirements of innovative e-mobility solutions with a unique assembly and interconnected technology. Optimized for highest power density at smallest size, the module is part of Bosch’s automotive inverter and eAxle. It is also available independently for manufacturers and suppliers and their own vehicle applications.

The secret of its high innovation level lies in the pioneering three-dimensional structure as much as in 15 years of experience in power module engineering and manufacturing on a global scale. The PM6.1 has a symmetrical low inductive layout that suppresses self-excited oscillation between parallel connected dies, leading to an exceptional high stability. What’s more, the sandwich structure enables high temperature operation and improves thermo-mechanical robustness. It is therefore the ideal match for demanding high-end applications: two to six chips in a parallel configuration of different sizes with max. 40 mm² are possible. With one mechanical platform for all performance variants, full scalability is ensured. This saves manufacturers the development costs associated with multiple platforms across their portfolio.

When it comes to semiconductors and SiC, Bosch has already achieved a lot of milestones – and according to our roadmap, the journey is far from over. We are pushing the boundaries of SiC technology specifically in the fields of performance and robustness. These improvements also directly influence our power modules, allowing for next generations to emerge. Planned future power module releases will cover power scaling, interface optimization, thermal performance and cost optimization. Stay tuned for more news!