一种单级高频AC/AC变换器

A Single Stage High Frequency AC/AC Converter

在LCD背光源、隧道照明等大功率LED照明领域,LED驱动电源需实现功率因数校正、输入输出隔离、多路恒流输出功能。为此,该文提出一种包括高频AC/AC变换模块和高频AC/DC变换模块的模块化多路输出LED驱动电源,并主要研究一种输出为高频正弦交流电压的单级高频AC/AC变换器,其内部包括功率因数校正和高频DC/AC变换两个功率变换单元。首先对单级AC/AC变换器的拓扑进行推演,然后分析其工作原理及性能特点。由于功率因数校正单元的工作原理及性能特点在以前的文献中有详细介绍,该文主要描述高频DC/AC变换单元的工作原理,并采用基波分析法对其性能进行分析。最后搭建一台输出功率为100W的单级高频AC/AC变换器实验样机,实验结果表明:在额定输入输出条件下,功率因数达到0.94,直流母线电容电压在全输入输出范围内最高为440V,满足实际应用需求。

In many high power applications, such as large scale LCD panel backlighting, tunnel lighting, etc, LED driver should realize the following three functions at least： power factor correction, input and output electrical isolation, and multiple constant current outputs. A modular multi-channel LED driver composed of high frequency AC/AC module and high frequency AC/DC modules was proposed. The main topic of this paper is a kind of single stage high frequency AC/AC converter with high frequency sinusoidal ac output voltage, which consists of two power conversion cells： power factor correction cell and high frequency DC/AC conversion cell. Firstly, the topology deduction of the single stage AC/AC converter was performed. Secondly, its operation principle was introduced. Since the operation theory and characteristics of the power factor correction cell have been analyzed completely in the previous publications, the main focus of this paper is the high frequency DC/AC conversion cell. The operation theory of the high frequency DC/AC conversion cell was described in detail and characteristics were analyzed based on the fundamental analysis method. Finally, a 100W prototype was built to verify the correction of the analysis. The measured power factor is 0.94 with normal input and output and the highest DC bus voltage is 440V in the whole input and output ranges, which meets the practical applications.