Analysis of a novel bi-directional rectifier with double DC bus voltage

This paper presents a current-controlled rectifier with double DC bus voltage that allows a bi-directional power flow capability and provides a clean sinusoidal line current. This converter can reduce the current harmonics owing to the power factor correction and the voltage harmonics due to circuit configuration compared with the conventional half-bridge pulse-width modulation (PWM) rectifier. The control signals of the power switches are derived from the DC link voltage balance compensator, line current controller and DC link voltage regulator. The carrier-based PWM scheme is employed to draw a clean sinusoidal line current, high input power factor, regulated DC link voltage and balance capacitor voltages. Three voltage levels are generated on the AC terminal of the adopted rectifier. The feature of bi-directional power flow can regenerate the stored energy in loads back to the mains and possibly reduce the size of the DC link capacitor. The principle of operation is confirmed by the computer simulations