Study On The Bridgeless Sepic Power Factor Correction Converter With One-cycle Control Strategy

With the continuous development of power electronics technology, PFC (Power Factor Correction) technology is constantly evolving. In terms of single-phase power factor correction, bridgeless Sepic power factor correction circuit is becoming more and more popular because it’s input current follows the input voltage automatically and it can easily be isolated between input and output parts. Currently, most studies on bridgeless Sepic PFC converters are about the main circuit topology, and relatively less study on the control strategy. Literature studies show that most of the switching devices in bridgeless Sepic PFC circuits are suffering from large voltage and current stress, which increases the losses on the switching devices and also reduces the efficiency of the circuits. To solve this problem, the bridgeless Sepic PFC converter with one-cycle control strategy is studied in this paper.Firstly, this paper introduces the research background and research status about power factor correction technology, and introduces the basic principles of the one-cycle control strategy as well as its application in PFC circuits. Secondly, the principle of bridgeless Sepic PFC circuit is introduced and then a set of appropriate parameters is determined. According to the principle of one-cycle control, one-cycle control equation for the bridgeless Sepic PFC circuit is constructed and the topology of the control circuit is given.On this basis, the simulation on the bridgeless Sepic PFC converter with one-cycle control with Simulink are given. The results show that the switching devices withstand less voltage and current stress compared with the voltage-mode control strategy.Finally, the experimental circuits are studied. According to the working principle of the main circuit, the devices in the main circuit are chosen and the control circuit including the reset integrators, voltage and current sampling circuits is designed. The experimental results are given. The results show that the switching devices bear less voltage and current stress under one-cycle control although the input current follows the input voltage and the output voltage can reach 50V in both control modes, which is consistent with the simulation results.