A bridgeless CUK PFC converter with positive output voltage

一种具有正输出电压的无桥CUK PFC变换器

¹ Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, 518057
² School of Automation, Northwestern Polytechnical University, Xi'an 710072, China

Received: 27 October 2020

Abstract

The output voltage of the traditional CUK PFC converter is negative, and an additional inverting amplifier circuit is needed, which increases the volume and cost of the converter. A new type of bridgeless CUK PFC converter topology is proposed in this paper, which makes the converter have a positive output voltage without the need of an additional inverting amplifier circuit, and has the advantages of simple control, high efficiency, and low cost. Through topology optimization, one input capacitor is reduced, and the two diodes are converted from the high-current working state of high frequency to low-current working state of power frequency, ordinary rectifier diodes can be selected instead of fast recovery diodes, thereby reducing the volume and cost of the converter. The converter works in DCM, so no current control loop is required, which simplifies the control circuit. In addition, the main switch is turned on under ZVS condition, and the output diode is turned off under ZCS condition, which reduces the switching loss and improves the efficiency of the converter. A simulation model was built in PSIM, and a prototype with a rated power of 150 W was fabricated to verify the effectiveness and superiority of the proposed converter. Experimental results show that the PF of the proposed converter is 0.995 7, and the input current THD is 3.78% under rated input conditions.

摘要

传统的CUK PFC变换器输出电压为负，需要附加反相放大器电路，增大了变换器的体积和成本。提出了一种新型无桥CUK PFC变换器拓扑，该拓扑在无需附加反相放大器电路的情况下使变换器输出电压为正，具有控制简单、高效率、低成本的优点。通过拓扑优化减少了1个输入电容，并使2个二极管从高频的大电流转换为工频的小电流工作状态，可选取普通整流二极管代替快恢复二极管，从而降低了变换器的体积和成本。该变换器工作在不连续导通模式下，不需要电流控制环，从而简化了控制电路。另外，主开关在零电压开关（ZVS）条件下导通，输出二极管在零电流开关（ZCS）条件下关断，降低了开关损耗，提高了变换器的效率。在PSIM中搭建了仿真模型，并制作了额定功率150 W的试验样机，验证了所提变换器的有效性和优越性。实验结果表明，在额定输入条件下，功率因数（PF）为0.9957，输入电流的总谐波失真（THD）为3.78%。