小功率电源和充电器的集成磁路分析和设计

The Analysis and Design of the Integrated Magnetics in Small Power Supplies

为了提高小功率电源,特别是5W以下电源的功率密度和效率,提出采用新型EI方式的集成磁路CUK电路。不同于常规的电路分析方法,本文通过建立磁路等效计算的模型,求出其输入输出零纹波的判定条件,所得的零纹波条件与电路分析方法吻合。并对该CUK型电路的EI型集成磁路进行设计和开关器件及电容的选择,得到整个充电器的功率密度和效率,最后利用Matlab电路进行仿真得到输出波形。本文的设计针对输出功率为1W、输出电压为5V、开关频率为240kHz的小功率充电器,设计结果表明了EI集成磁路变压器是目前提高小功率充电器效率和功率密度的新型拓扑结构。

To improve the efficiency and the power density of the small power supplies and chargers, especially the supplies with the power below 5W, a new integrated magnetics transformer with the El core is introduced, which composes the CUK circuit. The integrated magnetics transformer with El core in CUK circuit is analyzed. The magnetic path model is built. From the model, it gets the conditions of zero ripples in input and output current. The conditions of zero ripples are accordant with those from the electrical circuit. The integrated magnetics design method and calculation are also present. The power density and efficiency are gotten after the capacitors and switch being selected. At last, the Matlab is used for simulation. The waveforms of the new integrated magnetics are gotten to check the new method and design result. The charger of lW, whose power is especially small, 5V and 240kHz is designed as an example.