基于PIN二极管模型的开关电源电磁干扰研究

Research on Electromagnetic Interference of Switch Power Supply Based on PIN Diode Model

本文采用电路-器件协同仿真的方法对开关电源中的电磁干扰进行了分析。本文采用了基于有限元的混合方法对双极扩散方程进行求解,建立能够准确展现导通和截止特性的PIN二极管子电路模型,并将其作为整流关键器件加载到开关电源电路中。在电路分析中分别加载商业软件PIN二极管模型和自建PIN二极管模型,获得两种不同情况下的分布电容电流、共模电压和差模电压,通过对比分析,认识了开关电源电磁干扰的物理特性以及关键器件模型对电磁干扰分析的影响。

In this paper, electromagnetic interference(EMI) of switch power supply is analyzed with a circuit-device co-simulation method. For constructing a PIN diode model which can describe the forward conduction and reverse-recovery characteristics more accurately, a hybrid method based on finite element method(FEM) is proposed to solve the ambipolar diffusion equation. And the constructed model is deployed as rectifier in the circuit. The commercial PIN model and the self-built model are loaded in the circuit for analysis respectively. By comparing the distributed capacitor current, common mode voltage and differential mode voltage that are obtained under such two different situations, the physical characteristics of EMI in the switch power supply and effects on the EMI analysis due to those crucial devices are acknowledged and analyzed.