22 kW Bi-Directional Active Front End (AFE)

This reference design demonstrates the application of Wolfspeed’s 1200V C3M™ SiC MOSFETs to create a 22kW three phase bidirectional active front end (AFE) converter for electric vehicle (EV) on-board charger (OBC); off-board fast charging; and other industrial applications such as energy storage systems and three phase PFC power supplies. This design operates as a standalone AC/DC converter and is compatible with both single-phase and three-phase inputs. It has two operating modes: power factor correction (PFC) mode and inverter mode. In both modes; the DC bus voltage is flexible to demonstrate operation under a range of conditions. The use of 1200V C3M™ 32mOhm SiC MOSFETs in a TO- 247-4 package provides the best figure of merit (FOM) and reduces switching loss and cross talk.

The design accomplishes

• Peak efficiencies of 98.5% in both PFC and inverter mode
• Power density of 4.6kW/L

This reference design is offered as a comprehensive design package which can be used as a starting point for new SiC designs.

Specifications

PFC Mode

• Three Phase Input Voltage: 305Vrms → 450Vrms line-line 50/60Hz
  Max current: 32A
  Output DC Voltage: 650V → 900V; Max power 22kW
• Single Phase Input Voltage: 180Vrms → 264Vrms 50/60Hz
  Max current: 32A
  Output DC Voltage: 380V → 900V; Max power 6.6kW

Inverter Mode

• DC Input Voltage: 350V → 760V DC
  Max current: 20A
• AC Output Voltage: 230Vrms 50Hz single phase
  Max power: 6.6kW

• Switching Frequency: 45kHz
• Tooled heatsink to simulate cooling plate
• CAN interface