电动汽车开关电源电磁兼容优化设计方法

Electromagnetic Compatibility Optimization Design for Switching Power Supply used in Electric Vehicle

针对电力电子设备严重的电磁兼容问题,分析得出功率器件对地的寄生电容是影响共模干扰传播的主要因素,采用有限元法和静电场原理建立了寄生参数的计算模型,并推导出了计算方法,通过基于控制寄生参数大小的方法提出了变换器系统电磁干扰的优化设计方法。实验结果表明,通过增大功率器件导热片与散热器之间导热硅脂的厚度,能够增大开关器件对地的寄生阻抗,使得传播到变换器电源线上的电磁干扰降低,从而提高变换器系统的电磁兼容性。

On the basis of serious electromagnetic interference produced by power electronic equipment,parasitic capacitance existing between transistor and heat sink is considered as the main factor disturbing common-mode loop.Calculation model of parasitic capacitance is established by using FEM and electrostatic field principle,and computing method is also derived.Electromagnetic interference improvement method for converter system is proposed by controlling the parasitic capacitance impedance.Experimental results show that changing the permittivity and thickness of the thermal conductive adhesive which are filled between the transistor heat-conducting plate and heat sink to can reduce the conducted interference.