Application of three-phase unfolder in electric vehicle drivetrain

This paper investigates control of the three-phase unfolder and associated isolated bidirectional dc-dc converter modules in motor drive applications. The resulting system is well-suited in the electric vehicle drivetrain as a high-power integrated ac fast charger. Compared with other methods using the motor as an ac interface when charging, this approach removes limitations on the motor type and winding configuration while easily achieving galvanic isolation. The full system with proposed controller is validated in simulation for max-torque-per-amp operation on a permanent magnet synchronous motor. An experimental system is constructed and tested with both an inductive load and unloaded motor.