Input impedance improvement by using digital compensation strategy for high power density rectifiers with wide load operation

In this paper, an improved control loop based on feedforward is proposed to reduce the total harmonic distortion of the input current (THDi), realizing power factor correction (PFC) in MCM. The frequency responses of the input impedance for a wide frequency range are improved and unified by adding feedforward duty-ratio to the output of the original current-loop. A 5 kW experimental prototype is built to verify the validity of this strategy. The experimental results show that the system has close to unity power factor (PF), and THDi is significantly reduced.