Application of SiC power device in Vehicle charger (OBC)

New energy vehicles require an on-board charger (OBC)that allows users to charge at home, work, and private/public sockets. OBC is an AC-DC converter consisting of a (PFC + isolated DC-DC) main stage.Main function: The grid voltage is connected to the vehicle charger through the ground AC charging pile and AC charging port to charge the electric vehicle battery. Common OBC power levels include 3.3 kW, 6.6 kW, 11 kW, and 22 kW.

In OBC systems, SiC MOSFETs (Metal-oxide-semiconductor field effect tube) can replace IGBTs (Insulated Gate Bipolar Transistors) and MOSFETs.

Advantages of SiC Device in OBC:

Fit Higher Operating Temperature Tolerance:
SiC power devices exhibit superior thermal resistance, enabling operation at higher temperatures. This is critical for OBCs, as charging generates certain amount of heat. SiC devices enhance system reliability and longevity by better managing high-temperature environments.

Faster Switching Speed:
SiC devices switch faster than traditional silicon-based devices, allowing higher switching frequencies. This means that the OBC can control current and voltage more effectively, reduce power loss and electromagnetic interference, and improve the response speed and conversion efficiency of the system.

Lower On-Resistance:
SiC devices have low on-resistance, which can reduce the power loss of switching devices. This is particularly important for OBC, as it reduces thermal dissipation, improves energy conversion efficiency, and shortens charging times.

Higher Voltage Tolerance:
SiC devices support higher voltage levels, offering greater design margin and stability. This ensures reliable OBC operation under diverse conditions, improving system stability and safety.