As the market demand for electric vehicles continues to increase – driven in part by government regulations on fuel efficiency, escalating fuel costs and an overall trend toward “greener” transportation options – a growing number of automotive manufacturers are incorporating the latest power electronic technology in their designs to improve overall performance, increase efficiency, and reduce cost, weight and complexity.
Hybrid electric vehicles (HEVs), plug-in hybrid electrical vehicles (PHEVs) and battery electrical vehicles (BEVs) all contain several critical systems that stand to benefit from wide bandgap power devices; these devices have the potential to enhance both the energy efficiency and performance of electric vehicles, which could enable early adopters to achieve a significant market advantage over their competitors.
As one of the leading wide bandgap semiconductor materials, silicon carbide (SiC) offers a number of proven performance advantages over conventional silicon technology, including higher voltage blocking capability, faster switching speed, lower on-state and switching losses, higher thermal conductivity, and higher surge resistance. These characteristics provide the platform for advanced power electronics subsystems that are at the heart of electric vehicle drivetrains, power converters and charging systems.
In a typical electric drivetrain vehicle, sophisticated power electronics are employed to manage the flow of energy between energy storage devices (batteries) and motor drive inverters. Improving the efficiency of these power electronics systems, which currently depend on conventional silicon power devices with limited voltage and power ratings, is critical for improving overall electric vehicle efficiency and reliability. By using the performance advantages of SiC power devices, electric drivetrains can achieve increased efficiency, higher power levels and power density, and reduced cooling system requirements. These system-level benefits yield increased vehicle performance, driving range per charge and decreased energy and/or fuel cost.
Fig. 1: EV charging systems benefit from the improved efficiency and thermal characteristics of Cree’s SiC Schottky diodes.
The significant performance enhancement that SiC can provide in an electric vehicle application can be shown