Prediction of Conducted Disturbances Generated by a DC/DC Converter

Abstract

This paper introduces a detailed approach to model and simulate conducted electromagnetic interference (EMI) in the time domain using Lt-Spice software. The focus of the study is on the Buck converter, with the aim of identifying and characterizing electromagnetic disturbance sources arising from the power supply. The research also seeks to analyze their propagation paths and examine the impact of switch selection and control parameters on the electromagnetic compatibility (EMC) signature of the converter. The proposed methodology employs a comprehensive modeling strategy that accounts for the interactions between various converter components and their associated parasitic elements. By accurately representing the electrical and magnetic fields in the time domain, the simulation captures the dynamic behavior of the system, allowing for a realistic assessment of conducted disturbances. The research begins with a thorough examination of the power supply and its switching behavior. Key device characteristics, including switching frequency, voltage, and current waveforms, are carefully analyzed to understand their influence on conducted EMI. Additionally, the model integrates parasitic elements linked to the power device, such as inductive and capacitive components, to address their impact on electromagnetic emissions. Furthermore, the study delves into the propagation paths of conducted disturbances, considering the parasitic elements of the converter's layout, such as PCB traces, cables, and connectors. It evaluates the effects of these elements on electromagnetic emissions, providing insights into propagation mechanisms and potential coupling paths. Various switch types, such as MOSFET or IGBT, are examined, and their effects on conducted EMI are evaluated. Through comprehensive simulations and analysis, the paper offers valuable insights into the conducted disturbances generated by the DC/DC converter, contributing to a comprehensive understanding of the system's electromagnetic behavior. The findings presented in this study can inform the design and optimization of DC/DC converters, facilitating the development of more EMC-friendly solutions.