基于I～P特性的反激式电源高频变压器磁芯选择

Core Selection of High Frequency Transformer Based on I ～ P Characteristics for the Flyback Power Supply

为了实现高频变压器磁芯的合理选择,提出了一种基于反激式电源I～P特性的高频变压器磁芯选择方法。该方法建立了考虑高频变压器和反激式开关电源外围电路的联合仿真模型,计算了不同磁芯对应的电源I～P特性曲线,借助拟合工具推导了不同磁芯的I～P特性拟合公式,根据磁芯最大工作磁密得到了不同磁芯对应的电源最佳输出功率,并结合电源的最大设计功率,实现了开关电源在不同功率应用区间的磁芯合理选择,有利于降低反激式开关电源的设计成本。研制了由两种不同磁芯构成的高频变压器样机,搭建了反激式电源模块功率特性测试平台,测试了工作电压为220 V时两种磁芯的I～P特性,并与联合仿真结果进行了比较,吻合较好,验证了该方法的正确性,为高频变压器的磁芯选择提供了参考。

In order to realize the reasonable selection of the core of high frequency transformer,a method of core selection for high frequency transformer based on I ~ P characteristics of flyback power supply is presented. In this method,a combined simulation model considering the peripheral circuits of high frequency transformer and flyback switching power supply is established, the I ~ P characteristic curves corresponding to different magnetic cores are calculated,the fitting formulas for I ~ P characteristics of different cores are derived by means of fitting tools,according to the maximum working magnetic density of magnetic core,the optimal output power of power supply corresponding to different magnetic cores is obtained,and based on the maximum design power of the power supply,the reasonable selection of the magnetic core of the switching power supply in different power application areas is realized,which is conducive to reducing the design cost of the flyback switching power supply. A high-frequency transformer prototype composed of two different magnetic cores is developed,and a flyback power supply module power characteristic test platform is built,the I ~ P characteristics of the two cores are tested when the working voltage is 220 V,and the results are compared with the joint simulation results. The result shows that the method is correct and serves as a reference for the core selection of high frequency transformer.