On low frequency conducted EMI: interference mitigation with focus on the DC switching harmonic in the time and frequency domains

Pena Quintal, Angel Eduardo (2023) On low frequency conducted EMI: interference mitigation with focus on the DC switching harmonic in the time and frequency domains. PhD thesis, University of Nottingham.

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The recent increase of interconnected electrical systems such as power supplies and communication links are creating problems associated with electromagnetic fields generated at different voltage levels and frequencies. Semiconductor switches used in for example Switched Mode Power Supplies are constantly increasing in power rating and frequency limits. In addition, wired communication links are also increasing the working bandwidth and channel capability to transfer more information in less time.

Smart grids are receiving much attention from companies and researchers all over the world. Two concerns that drive the research carried out on smart grids are Power Quality and Signal Integrity. This work presents an analysis of conducted emissions with two aims.

Firstly, an analysis is made of the simulated and measured data when a DC system generates electromagnetic interference and how to improve or mitigate it with certain frequency modulation techniques by spreading the spectrum of the switching frequency in agreement to an established standard.

Secondly, a demonstration of the coupling effects as one of the major concerns when dealing with Electromagnetic Interference sources is presented experimentally. Statistical analyses for these tests are performed to understand the main causes and possible actions to suppress interference and to address Electromagnetic Compatibility between devices.

The work presents the following findings.

An understanding of the important parameters for frequency modulation techniques called as Spread Spectrum. These parameters are the rate of change for the modulating signal and the modulation index that controls the switching frequency of a modulated DC-DC converter to mitigate the interference measured.

The importance of an auxiliary time domain (Bit Error Rate) analysis to measure the interference of a DC-DC converter modulated by Spread Spectrum to understand the main drawback in the emissions measured from a different point of view by means of a Crosstalk environment.

The conclusion that Bit Error Rate measurement of a communication signal cannot be decreased using Spread Spectrum Modulation for the power converter as the EMI source.

The results obtained use data measured using an EMI receiver and where possible a simulation describing the most important parameters. This work provides interesting and useful points to analyse the Spread Spectrum technique applied to DC power converters and the main advantages and disadvantages.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Greedy, Steve
Sumner, Mark
Keywords: Electromagnetic fields; Smart grids; Electromagnetic interference; Frequency modulation; Coupling effects; Electromagnetic compatibility
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7800 Electronics
Faculties/Schools: UK Campuses > Faculty of Engineering > Department of Electrical and Electronic Engineering
Related URLs:
Item ID: 76663
Depositing User: Pena Quintal, Angel
Date Deposited: 11 Jan 2024 10:21
Last Modified: 07 Mar 2024 10:05
URI: https://eprints.nottingham.ac.uk/id/eprint/76663

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