Techniques and Challenges in Conducted EMI Analysis of Renewable Energy Systems

Renewable energy sources have been widely integrated into modern power systems, leading to the massive use of power converters, which represent the main sources of conducted electromagnetic (EM) noise. Furthermore, power grids employ interactive devices including smart meters that resort to powerline communication (PLC) technology and are usually more susceptible to EM noise than traditional electrical machinery. This paper provides a state-of-the-art overview of conducted EM interference (EMI) analysis in power systems, focusing on EMI prediction models, PLC coexistence issues, and measurement challenges. Insights into the use of various methods in different application scenarios are provided, and relevant future studies are foreseen

A Flexible Black-Box Model for Conducted Emission Predictions with Different Switching Frequencies

Black-box modeling technique is an efficient approach to represent the electromagnetic interference behavior of power converters, whose presence may cause malfunctioning in adjacent electronic devices. Although developing a black-box model is simpler and less demanding than extracting an explicit circuit model, model effectiveness is limited to certain operating conditions, such as a fixed modulation strategy. In this work, a flexible black-box model is proposed, which can be effectively used for prediction also in case of different modulation conditions without requiring a new estimation of model parameters if modulation parameter (such as the switching frequency) changes. Flexibility is achieved by modeling time-domain noise waveforms using an analytical curve-fitting model or an autoregressive model, whose accuracy is compared in time and frequency domain. The proposed model is experimentally verified on a boost converter operated with different switching frequencies

Positioning Uncertainty of Near-Field Probes

This work stochastically analyzes the positioning uncertainty of electric near-field probes. For this purpose, a virtual test bench is built and simulated in a full-wave solver using a Monte Carlo method, showing its impact on the probe factor

Test Design Methodology for Time-Domain Immunity Investigations Using Electric Near-Field Probes

This article investigates the possibility to develop time-domain immunity tests using electric near-field probes, for flexible customization of broadband input waveforms injected into specific pins of PCBs. For this purpose, a test design methodology is proposed, which is based on circuit modeling of the injection mechanism on the one hand, and on pulse design and equalization on the other hand. Two circuit models are developed. The former employs measurement/simulation data along with port-reduction techniques to model noise injection through near-field probes by means of internal induced sources. Conversely, the latter model only includes passive components and is derived starting from physical observation of the involved phenomena. Both models are compatible with circuit solvers and can be easily adapted for different traces under test. Since pulse-like noise is usually broadband, suitable stress waveforms are utilized to obtain different noise spectra. Also, in order to precisely control the shape of the waveform reaching the targeted pin, an equalization procedure is employed. These models and techniques can be easily applied to amplification systems originally designed for frequency-domain tests, thus providing a comprehensive solution for the design of broadband immunity tests in the time domain. The feasibility and accuracy of the proposed methodology are proved by full-wave simulations and measurements

Analysis of Near-Field Probing Techniques for Immunity Tests

This work experimentally investigates the performance of near-field probes as injection devices for wideband immunity tests. To this end, the coupling effectiveness and resolution of different kinds of magnetic and electric near-field probes are firstly investigated in terms of S-parameters measured with the probes placed on microstrip traces. Different test benches are set up and experimentally characterized in order to investigate the characteristics and determine the frequency response of the transfer function of a typical measurement chain for immunity verification. Finally, time-domain near-field tests employing arbitrary waveform generators are introduced, showing the feasibility of injecting customized wideband noise waveforms at specific pins

Effects of the Switching Frequency of Random Modulated Power Converter on the G3 Power Line Communication System

Power Line Communication (PLC) technologies utilize existing power cables for both power and data transmission which minimizes cost and complexity. However, recent studies show that alternative modulation schemes such as Random Pulse Width Modulation (RPWM), applied to power converter to minimize conducted emissions, have possible side effects on the PLC system. In this work, the effects of the switching frequency of randomly modulated power converter on the G3-PLC system is investigated. To this end, a range of switching frequencies from 10 kHz-100 kHz is applied to a randomly modulated DC-DC converter and its potential effect on the G3-PLC is studied. Experimental results confirmed that switching frequencies near the bandwidth of the G3-PLC caused significant disturbance and possible coexistence issue compared to the frequencies out of this range. Moreover, there is a tradeoff between Electromagnetic Interference (EMI) reduction and coexistence issue that is Random Frequency Modulation, which is very effective for EMI reduction, is found to be very disruptive for G3-PLC, compared to alternative random modulation techniques like Random Pulse Position Modulation

Alternative radiated susceptibility test methods at unit level

This article briefly illustrates and discusses the possibility to develop alternative, simplified test methods for radiated susceptibility testing at unit level for the aerospace sector. The rationale here discussed, and the alternative test methods here illustrated, are targeted to the development of a testing approach with deeper physics' sense, quicker and less expensive in order to help the industrial design process of equipment for spacecraft. The theoretical basis of this analysis is the possibility to enforce equivalence (in terms of common mode current) among the effects due to field-to-wire-coupling, bulk current injection and crosstalk, under suitable assumptions. Two dual approaches are considered, one aimed at achieving deterministic equivalence, the other enforcing equivalence in statistical terms. Pros and cons of the proposed alternative test methods are discussed by illustrating the outcomes of ad hoc setups and a wide experimental campaign