Bridgeless Buck-Boost PFC Rectifier with Positive Output Voltage Suitable for LED Driving

摘要

In this paper, a bridgeless buck-boost PFC rectifier with positive output voltage is presented. This circuit is designed to operate in the discontinuous conduction mode (DCM). Due to the DCM, this PFC rectifier is easy to control and has no reverse recovery currents created from the diodes. Via output voltage sensing along with the traditional voltage-follower control, a suitable control force is created so as to drive the power switches of this PFC rectifier. Therefore, for this PFC rectifier, the output voltage is kept constant at a desired value as well as the input current follows the input voltage as tightly as possible. Moreover, the corresponding harmonic distortion meets the requirements of the IEC6100-3-2 Class C harmonics standard, and hence the proposed rectifier is suitable for driving the LED. Eventually, by means of mathematical deductions and experimental results, the effectiveness of the proposed bridgeless buck-boost PFC rectifier is demonstrated.