Design and implementation of EMI filter for high frequency (MHz) power converters

Abstract

Abstract-The fabrication of emerging power semiconductor devices and high frequency PCB power transformers has made it possible to design the power converters in MHz switching frequency range. However, the higher switching frequency, di/dt loops and dv/dt nodes in power stages of these converters generate higher order harmonics which causes Electro Magnetic Interference (EMI). It is commonly believed that the EMI has worst affect in the converters switching in MHz frequency range than the converters operating below 150 kHz. Thus, it is important research direction to investigate the consequences of implementing a line filter to suppress the conducted EMI in high frequency power converters. In this paper, the measurements, and analysis of the conducted EMI in emerging power converters, switching in MHz frequency range, and the design of the filter for its suppression is presented. The design of LISN and its PCB implementation for EMI measurements is presented. The measurement of conducted EMI of a half bridge DC-DC converter switching at 3.45 MHz and the analysis of the frequency spectrum is discussed. The design, PCB implementation and characterization of the EMI filter and the measurement of the suppressed conducted noise by applying the filter are also discussed.

Hybrid PLC‐VLC channel model and spectral estimation using a nonparametric approach

“…The devices used in VLC may pollute the PLC channel by feeding back to the electrical network the period impulsive noise generated during rectification and switching activities . It is known that converters connected to the power network are equipped with an electromagnetic interference (EMI) filter used to attenuate the noise going from the converter to the electrical network and vice versa . Nevertheless, a nonnegligible amount of noise is still flying between the electrical network and the device.…”

Design of Coreless PCB Transformer for DC/DC Converter Applications

“…The fly-back converter is the most frequently used SMPS circuit in low power uses. As, in converter the switching frequency is amplified, the power MOSFET's switching losses increase which brings about a reduced hard switched power converter efficiency accordingly high electromagnetic interference (EMI) [3]. Besides, with the assist of the soft switching tactics like zero current switching (ZCS) and zero voltage switching (ZVS), the electromagnetic interfering would be reduced [4,5].…”

Self-oscillating galvanic isolated bidirectional Very High Frequency DC-DC converter

“…Using resonant converters the switching losses can be significantly reduced, these types of converters are used in [1]- [5]. Increasing the switching frequency into the Very High Frequency ( VHF = 30 MHz -300 MHz) reduces the value as well as the physical size of passive components significantly, not just the energy storing components inside the converter also the EMI filter can be greatly reduced [6], [7]. The Class-E DC-DC converter topology, presented in [8] inspired by [9], is made with an inverter and a rectifier that both uses a resonant circuit to enable soft switching.…”