风冷冰箱控制板风扇电机驱动电路EMI问题改善方案分析

Analysis of EMI improvement for fan motor drive circuit in main board of air-cooled refrigerator

本文研究了电冰箱控制板使用Mos驱动控制风扇电机引起的电磁干扰(EMI)问题,找到了风扇电机驱动电路主要EMI干扰来源,并提出了通过调整buck电路电感使其工作在DCM模式、续流二极管并联RC吸收电路、降低Mos开关速度,三个方案来解决EMI问题。

This paper studies the electromagnetic interference （EMI） caused by using Mos drive to contrul fan motor in refrigerator main board, finds out the main EMI interference sources of fan motor drive circuit, and puts forward three schemes by adjusting the inductance of buck circuit to make it work in DCM mode, adding RC snubber circuit in parallel with the fly-wheel diode or reducing Mos switching speed, to solve the EMI problem.