Powering Forward: Electric Propulsion in Heavy-Duty Trucks

June 06, 2024 by Darshil Patel

BAE System and Eaton tested their electric drive solution on a commercial demonstration truck.

Electric drive technology for heavy-duty commercial trucks is experiencing significant advancements, with power electronics leading the way. Power systems, like inverters, are becoming more compact and efficient. Semiconductors using silicon carbide (SiC) and gallium nitride (GaN) are increasingly utilized in these power electronics as they offer superior thermal and electrical properties, allowing higher power densities and more efficient thermal management. However, challenges remain in scaling these advanced power systems into existing truck architectures.

Electric transmission significantly affects the efficiency of propulsion systems by optimizing electric motor performance across various driving conditions. Single-speed transmission, commonly used in electric vehicles (EVs), allows the motor to operate efficiently within its optimal range, reducing energy losses associated with gear shifting and complex transmission mechanics. However, multi-speed transmission developed for heavier vehicles can enhance performance, efficiency, and range, particularly for heavy loads and steep grades.

BAE Systems and Eaton tested their integrated electric drive system for medium—and heavy-duty trucks. The system combines BAE's advanced electric motor and power electronics with Eaton's HD or MD 4-speed EV transmission, showcasing a promising leap forward in heavy-duty electric propulsion.

BAE’s electric commercial truck

BAE’s electric commercial truck. Image used courtesy of BAE Systems


Modular Power Control System

BAE's modular advanced power electronics are at the heart of the heavy-duty truck electric drive solution. The architecture uses fewer components, cables, and connections, saving space and weight in the vehicle. Moreover, it simplifies OEM integration and lowers overall cost.

BAE's power modules use advanced materials and modular design. By employing SiC devices, the system improves heat management, reduces weight, and increases power density. Moreover, GaN transistors provide faster switching and reduce component size. Using interchangeable component modules for powering single, dual, or multi-motor configurations further streamlines the design, reducing the need for multiple unique parts. As a result, the electric drive configurations use 50% fewer connections, wires, and cables than conventional systems. This enhances reliability and eases assembly while reducing potential failure points.

This advanced technology offers several advantages over conventional electric drive systems. The design's modularity and flexibility make it easier to adapt the system to various vehicle configurations. However, the complexity of integrating SiC and GaN components and ensuring compatibility across different vehicle platforms poses a significant engineering challenge.


BAE, Eaton Support Commercial Electric Trucks

BAE Systems and Eaton teamed up in 2023 to provide electric drive solutions for the medium-duty truck market. They expanded their collaboration to include heavy-duty commercial trucks above 19 tons, such as delivery trucks, regional haul trucks, and buses.


HD transmission.

HD transmission. Image used courtesy of Eaton


BAE Systems combines its electric motor and high-power density power modules with Eaton's HD 4-speed EV transmission to support a complete heavy-duty EV system. This builds upon their existing MD-4 solution (based on Eaton's MD 4-speed transmission), designed for medium- and heavy-duty applications.

They tested their integrated electric drive system based on MD-4 for medium- and heavy-duty commercial trucks. The test took place at Eaton's proving grounds in Michigan on a Class 7 demonstration vehicle, where the test truck met all key on-road performance milestones.