关键词: 电磁兼容, 功率电感, 磁场耦合, PCB布局, 屏蔽

Abstract: The magnetic field radiation from board-level power inductor poses a significant challenge in the electromagnetic compatibility (EMC) design of switching power supplies. The near-field coupling mechanism between the inductor and adjacent sensitive loops is complex, and existing layout rules often rely on empirical experience, making it difficult to quantitatively evaluate and mitigate risks in the early stages of development. To address the issue, taking a case of excessive interference power in a certain type of dehumidifier as the starting point, a method for analyzing and suppressing the magnetic coupling of power inductor based on the combined simulation of ANSYS HFSS-Circuit is proposed. By constructing six sets of comparative simulation models of the power inductor and sensitive loops, systematically investigates the influence of relative position (same layer/different layer), loop orientation (perpendicular/parallel to the PCB plane), and aluminum foil shielding on coupling strength, quantitatively revealing the sensitivity of key layout parameters. Furthermore, the research traces and analyzes the 21.34 MHz high-frequency noise generated by the switching transistor ringing. Based on the above analysis, specific guidelines for PCB layout and EMC design were summarized, providing a theoretical basis and engineering guidance for the electromagnetic compatibility design of switching power supplies.

Key words: Electromagnetic compatibility, Power inductor, Magnetic field coupling, PCB layout, Shielding