To achieve a zero-emission future, the automotive industry urgently needs transformation. Automakers must accelerate the launch of differentiated electric vehicle models. NXP, in collaboration with Wolfspeed, has jointly introduced a fully validated 800V traction inverter reference design, effectively helping EV system architects overcome numerous technical hurdles.

Power Inverter Module Analysis

To support automotive partners and accelerate vehicle electrification, NXP and Wolfspeed have jointly launched a fully validated 800V traction inverter reference design. This design helps EV system architects effectively overcome multiple challenges, including selecting appropriate components to improve system efficiency, meeting functional safety certification standards, and ensuring long-term reliability.

The EV traction inverter reference design is a complete system solution that integrates the Arm® Cortex®-M7-based S32K39 MCU, the functional safety-compliant FS26 system basis chip for power management, and the latest-generation high-voltage isolated gate driver GD3162. To complete the system, the design also includes Wolfspeeds 1200V six-pack YM SiC power module.

Complete ECU solution based on NXP reference design and Wolfspeed SiC power module

This EV traction inverter reference design has been jointly tested using a hardware-in-the-loop (HIL) setup at the Wolfspeed Munich laboratory. Under 800V battery operating conditions, the peak power exceeds 300kW.

Test results from the laboratory HIL setup

Efficient Design: Dynamic Gate Strength to Meet Different Power Demands

Laboratory simulation results show that overall efficiency improves by approximately 1% thanks to the proprietary features of NXPs high-voltage gate driver. This feature allows designers to dynamically adjust the gate drive signal strength based on real-time operating conditions, achieving a balance between efficiency, switching speed, and electromagnetic compatibility. According to models based on the Worldwide Harmonized Light Vehicles Test Procedure (WLTP), this design is expected to increase driving range by approximately 14 miles compared to traditional EV solutions.

Efficiency improvement results

Designed with Functional Safety in Mind: System-Level Functional Safety Documentation Beyond Device Data

In terms of functional safety (FuSa), compliant components are always designed with high quality and reliability as top priorities. Safety is integrated into every aspect of design, manufacturing, documentation, and technical support. The EV traction inverter reference design adopts key components compliant with the highest risk level ASIL D, including NXPs S32K396 MCU, FS2633 system basis chip, and GD3162 high-voltage gate driver. To further simplify customer integration, the design also provides FuSa documentation, such as the system safety concept, which details the decomposition from assumed safety goals to safety requirements at the hardware and software levels.

Building a Reliable and Long-Lasting Superior Design

Implementing an 800V traction inverter requires silicon carbide solutions. Compared to traditional silicon IGBTs, SiC material is inherently more reliable and durable. Wolfspeed has seized the opportunity to incorporate advanced packaging technology into its automotive-grade YM package, further enhancing system durability.

The 1200V six-pack YM SiC power module uses a direct-cooled copper pin-fin baseplate design. By immersing the pin fins directly in coolant, it not only simplifies system assembly but also significantly improves thermal performance. Additionally, the module uses a silicon nitride substrate, a robust ceramic material with excellent thermal shock resistance and wear resistance, effectively dissipating heat from the chips to lower system operating temperatures. Another innovative packaging feature is sintered chip attachment technology. This advanced die-attach method creates a strong bond between the chip and the silicon nitride substrate, ensuring outstanding thermal conductivity and mechanical durability, supporting higher power output and providing excellent thermal cycling performance. The direct-cooled copper pin-fin technology combined with sintered chip attachment technology improves both thermal performance and system lifespan.

The YM module replaces traditional wire bonds with copper top-side clips, significantly enhancing the modules current-carrying capacity and power cycling lifetime. At the same time, its optimized terminal layout effectively reduces package inductance, minimizes voltage overshoot, and achieves ultra-low switching losses. To reduce potential mechanical failure risks, the automotive-grade YM module uses a hard epoxy resin encapsulation. Compared to gel-based packages, epoxy molding compound not only provides excellent moisture resistance but also offers superior structural integrity. By combining sintered chip attachment, copper clips, and epoxy molding compound, the modules lifespan is extended up to three times compared to competing products.

Wolfspeeds six-pack YM-SiC power module

These advanced packaging technologies underpin the AQG324-certified YM3 power module, effectively addressing the challenges of operating in harsh automotive environments. This design ensures consistent performance and endows the module with exceptional durability.

NXP Products

The 800V traction inverter reference design jointly created by NXP and Wolfspeed marks a significant step forward in the automotive industrys transition to electrification. This reference design addresses key challenges faced by EV designers, including improving energy efficiency, functional safety, and long-term reliability, ensuring that EV performance can match or even exceed that of internal combustion engine vehicles. With dynamic gate strength adjustment technology and advanced silicon carbide power modules, this reference design serves as a vital tool for EV designers, helping to create high-quality, energy-efficient, and safe electric vehicles while ensuring excellent performance throughout their entire lifecycle.