关键词: 变频空调, 传导发射, 电磁干扰, 抑制策略

Abstract: The rapid switching operations of high-frequency power devices in the DC fan drive systems of household inverter air conditioners are prone to inducing severe conducted electromagnetic interference (EMI) through parasitic coupling. The issue has emerged as a critical bottleneck constraining the electromagnetic compatibility (EMC) performance of air conditioning products. Focusing on the conducted emission issues of DC fan systems, thoroughly investigates the coupling mechanism constituted by high-frequency power devices and the parasitic capacitance of motor windings in the blowing mode. Furthermore, an equivalent circuit model for conducted emissions, incorporating high-frequency parasitic parameters, is established. On this basis, a suppression strategy for conducted interference is proposed, based on regulating the coupling path of the DC fan's parasitic capacitance, thereby achieving effective shunting of the interference energy. Consistent results from simulation verification and experimental tests demonstrate that this strategy significantly suppresses the electromagnetic interference generated by the DC fan module and effectively attenuates the conducted emission levels of the air conditioning system, provided a feasible and practically valuable systematic solution for the mechanism analysis and proactive design of conducted EMI in inverter air conditioners.

Key words: Variable-frequency air conditioner, Conducted emission, Electromagnetic interference, Suppression strategy