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

PSpice-simulink co-simulation of the conducted emissions of a DC-DC converter with random modulation

This paper investigates the beneficial effects of Random Modulation strategies in reducing the conducted emissions generated by DC-DC converters. The analysis is carried out by PSpice-Simulink co-simulation in order to achieve effective modelling of the converter on the one hand (PSpice), and easy implementation of the modulation scheme on the other (Simulink). Particularly, Random Pulse Width Modulation is used to control a DC-DC converter involving second-generation Cree SiC MOSFET. The non-linear characteristics of the converter as well as its parasitic elements are considered by the PSpice model. The predicted CM and DM emissions are compared versus those obtained by standard PWM, showing a significant reduction of the overall emissions in the frequency range of interest

Limitations in Applying the Existing LISN Topologies for Low Frequency Conducted Emission Measurements and Possible Solution

The use of power electronic converters to interface renewable sources and intelligent loads to electricity distribution systems is increasing at a rapid rate as they bring flexibility and control to the system. However, they also bring an increased level of conducted emissions (CE) to the system due to their switching behaviour - usually at a few tens of kilohertz. The increased emissions are seen particularly in the low-frequency range (2-150 kHz) and it may possibly impair the operation of information and communication technology (ICT) equipment connected to the same system. It is therefore essential to assure accurate measurement of low frequency emissions from a particular piece of equipment, to ensure it meets standards for electromagnetic compatibility (EMC). According to EMC standards, CE are usually measured by using a Line Impedance Stabilization Network (LISN). However, the standard LISN bandwidth does not fully cover this low-frequency range (2-150 kHz), resulting in inaccurate measurement and poor repeatability. This paper examines this issue, by investigating the limitations in using the CISPR 16-1-2 LISN topology for CE measurement at low frequency in a grid-tied inverter system, and by proposing a possible solution, which requires adding extra components to the LISN circuit