The single-phase single-switch PWM three-level high power factor rectifier for DC network application

In this paper, a new unidirectional three-level rectifier is presented to draw sinusoidal line current with low THD and unity power factor. The adopted rectifier consists of a diode bridge, a power switch and two blocking diodes. Low cost, simple structure and convenient control are the main advantages of this rectifier. A two loop controller is developed to control the adopted rectifier. A voltage controller based on PI controller regulates the DC link voltage in the outer loop, while the current controller based on hysteresis comparator in inner loop control the input current. An input current sign detector is used to select the appropriate switching state from a look-up table. Analytical and computer simulation results are presented to show the efficient operation and advantages of the presented rectifier.