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Author: search.filters.author.Ngaopitakkul, AtthapolSubject: search.filters.subject.electromagnetic interference (EMI)

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    Attenuation of Electromagnetic Interference Generated by High-Frequency Switching Devices
    (2022-01-01)
    Jettanasen, Chaiyan
    ;
    Ngaopitakkul, Atthapol
    ;
    Pothisarn, Chaichan
    A frequency modulation (FM) radio signal receiver is an important device for radio transmitters. The FM radio signal receiver is mounted on the radio transmitter, and its circuit is connected to the electronic system inside the radio transmitter. Therefore, it is necessary to consider the electromagnetic interference (EMI) produced by the FM radio signal receiver to prevent damage caused by interference. This study investigated the EMI characteristics of an FM radio signal receiver in terms of conducted emissions and radiated emissions. The conducted emissions were measured in the frequency range of 150 kHz to 30 MHz and exceeded the CISPR22 standard at frequencies of 370 kHz (-2.4 dB) and 480 kHz (-6.5 dB). The radiated emissions were measured in the frequency range of 30 MHz to 1000 MHz and exceeded the EN55022 standard at a frequency of 33.93 MHz (-13 dB). The conducted emissions were reduced using an axial ferrite bead, while the radiated emissions were attenuated using multipoint grounding and shielding techniques. The axial ferrite beads could attenuate the conducted emissions by 8 dB. The multi-point grounding and shielding techniques attenuated the radiated emissions by approximately 22 dB. These EMI attenuation methods demonstrated satisfactory attenuation performance and resulted in the EMI satisfying the relevant standards.
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    Impact of Electromagnetic Interference Filter Performance in a System without and with Grounding for Supporting the Nanogrid Road Lighting System
    (2021-04-27)
    Jettanasen, Chaiyan
    ;
    Bunjongjit, Sulee
    ;
    Ngaopitakkul, Atthapol
    This study focuses on the comparison of conducted electromagnetic interference (EMI) mitigation for a nanogrid road lighting system, using a passive EMI filter between ungrounded and grounded systems. An inverter was used as the equipment under test in the experiment. The inverter is a power conversion device that receives power from the source and supplies power to the AC electrical load of an LED luminaire. There are two points where the self-generated noises propagate to other nearby devices/equipment. For this reason, this study shows the EMI spectrum from both the DC input and AC output of the inverter. The results of both sides were additionally compared between the two case studies: ungrounded and grounded systems. The real EMI testing results were also compared with the EMI/electromagnetic compatibility standard. The results confirm the effectiveness and benefits of system grounding, integrated with the proposed passive EMI filter.