A. S. de Beer

Effects of LED lamps on the power-line communications channel

LED (Light Emitting Diode) lamps have recently come on to the market as energy efficient alternatives to incandescent light bulbs. Although energy effective, they inject conductive noise into the power-line system. This can have a detrimental effect on the power-line communications channel. This paper investigates these effects when LED lamps are seen as noise sources on the power line. It shows that there are two classes of LED lamps - depending on the noise generating electronics used as drivers for the light emitting diodes. Different driver electronics have different influences in different parts of the emission spectrum. It is shown that in the CENELEC band: (3kHz-150kHz) the interference level from LED lamps is significantly below the allowed maximum PLC signal levels. In the band 150kHz-30MHz however, PLC signals compete with Electromagnetic Compatibility (EMC) levels and the SNR can be equal to zero, but only if the lamps have active power electronic converters.

The influence of fluorescent lamps with electronic ballast on the low voltage PLC network

The fluorescent lamps or fluorescent tubes are low pressure mercury-vapor gas-discharge lamps that use fluorescence to produce visible light. These lamps inject noise into the power-line communications channel. This can have a detrimental effect on the power-line communication system. In this paper we investigate the effects when the fluorescent lamps with electronic ballasts are seen as noise sources on the powerline channel. It is shown that in the CENELEC band: (3kHz-150kHz) the interference level from fluorescent lamps is significantly below the allowed maximum PLC signal levels. In the band 150kHz-30MHz however, PLC signals compete with Electromagnetic Compatibility (EMC) levels. The operational method of the electronic ballast inside the fluorescent lamp is explained.

The impact of the CFL lamps on the power-line communications channel

A number of measurements show the results of the harmonics and conducted emissions from “Energy-Savings” Compact Fluorescent Lamps (CFL) when connected to the power-line communications channel. Different CFLs from different manufacturers were investigated. The paper covers the CENELEC band, as well as the broadband communications channel: 150kHz-30MHz. The obtained results show the levels of harmonics and interference that these types of lamps produce. It shows that CFLs produce interference in the 3kHz-150kHz band, but this pose no risk for PLC. Some CFLs do however produce interference in the 150kHz-30MHz band that can interfere with power-line communications.

Nonlinear resonant pole zero voltage switching in a self oscillating DC to DC converter with magnetic feedback

The self-oscillating inverter with magnetic feedback has proven itself over the years as a simple and robust converter. The fixed-ratio DC-to-DC converter based on this inverter is described, and it is shown that zero voltage switching can be achieved with minimal modifications to the circuit. The topology distinguishes itself from other zero-voltage-switching, clamped voltage topologies by the fact that the inductor in the parallel resonant tank not only is nonlinear, but may include a series resistor. Dimensioning of the soft switching network is restricted by conditions imposed by the feedback circuit and base drive requirements. A method for analysis and experimental results is presented.<<ETX>>

Problematic aspects when using a LISN for converter EMI characterisation

In this paper it is shown that conducted interference from a power converter differs when measured with and without a Line Impedance Stabilization Network (LISN). This is problematic as the true Electromagnetic Interference (EMI) of a converter is therefore difficult to characterize. Possible reasons for this difference are discussed showing to the influence of a LISN on measurements.

The effect of leakage inductance and snubbing on electromagnetic interference generated by a flyback converter

Leakage inductance is known to affect power transfer of transformers and coupled inductors, as well as causing voltage spikes across converter switches possibly damaging them. The standard solution is to implement a snubber to reduce these voltage spikes. This paper investigates the effects of leakage inductance as well as snubbing on conducted EMI emissions.

Contactless power-line communications

Power lines that carry communication signals tend to produce radiated electromagnetic interference (EMI). In this paper it is shown how this, usually negative effect, is used for contactless signal transmission. Commercial PLC modems operating in the 150kHz - 30MHz band are used and LAN signals are contactlessly transmitted and received up to 2m.

Some considerations for miniaturized measurement shunts in high frequency power electronic converters

Power semi-conductors are able to achieve switching transients within a few nanoseconds and possibly even faster. These fast switching transients will need to be measured and analyzed thoroughly. In this paper four different types of shunt constructions and installations are tested on the same power electronics circuit, giving widely diverse results. Interpreting and analyzing these measurement results will assist in developing accurate current measurement devices for fast switching transient power electronic converters of the future.

On mercury vapor lamps and their effect on the smart-grid plc channel

The mercury vapor lamp is the oldest high intensity discharge technology lamp that uses an electric arc, and comes in different shapes and designs. It creates a very bright light by using an arc through vaporized mercury in a high pressure tube. This lamp can cause unwanted interference to the smart-grid network or power line communications channel when connected to the channels wiring system. In this paper we investigate the negative effects that the mercury vapor lamps with electric ballast have on the smart-grid PLC channel. This can have a strong and negative effect when using the smart-grid PLC network to control the automatic switching of lamps in public places. The narrowband and broadband channels are investigated where the interference level from mercury vapor lamps is significantly below the allowed maximum PLC signal levels on the band: (3 kHz - 150 kHz), and competes with Electromagnetic Compatibility (EMC) levels on the 150 kHz - 30 MHz band. The mercury vapor lamp uses an electric ballast to connect to the powerline system. This connection is explained in detail.

The influence of high pressure sodium lamps on the power line communications channel

The high pressure sodium lamp is a high energy outdoor light source that belongs to the high intensity discharge lamp family. It comes in different shapes and requires a ballast to start it. The high pressure sodium lamp is a source of interference to the power line communications channel as it injects noise when connected to the 220V mains. This paper investigates the influence of the high pressure sodium lamp on the narrowband and broadband power line communications channel. It is shown that the frequency band: 3kHz-150kHz is not highly infected whereas in the band: 150kHz-30MHz, PLC signals compete with Electromagnetic Compatibility (EMC) levels.