High Power Density Isolated Cuk Converter

DC-DC converter is widely used in all kinds of electronic devices. There have more demands for DC-DC converter with the higher integratation and more complicated function of the electronic device. Such as higher power, smaller volume and losses. The purpose of this paper is to find a better solution for 28V-to-12V DC-DC switch-mode power supply (SMPS) application. The power supply should have excellent overall performance including its efficiency, power density, and ripple, etc.The isolated Cuk circuit topology is used in this converter. Firstly, the isolated Cuk topology is analyzed theoretically in this paper. Up to now, there have seldom literature that makes detailed analysis about the isolated Cuk topology. Most of the literatures discuss the relation between the input voltage and the output voltage only. They omit the practical voltage and current of the internal components. This paper analyzes the voltage and current of the internal components and derives the parameter calculation method of the main components in the Cuk topology. Secondly, the design principle of high-frequency (HF) transformer is discussed. The paper presents the parameter evaluation method of the HF transformer. Then, two kinds of Zero-Voltage-Transition (ZVT) circuit is analyzed and compared. At last, the paper introduces the implementation of the power supply circuit, gives the results of simulation and experiment, and summarizes the conclusion of the whole experiment.The power supply in the experiment did not reach the performance we had expected. But the analysis in the paper and the experiment results is very helpful for the research of Cuk topology in the future.