Electromagnetic Interference and Compatibility

Recent progress in the fields of Electrical and Electronic Engineering has created new application scenarios and new Electromagnetic Compatibility (EMC) challenges, along with novel tools and methodologies to address them. This volume, which collects the contributions published in the “Electromagnetic Interference and Compatibility” Special Issue of MDPI Electronics, provides a vivid picture of current research trends and new developments in the rapidly evolving, broad area of EMC, including contributions on EMC issues in digital communications, power electronics, and analog integrated circuits and sensors, along with signal and power integrity and electromagnetic interference (EMI) suppression properties of materials

Investigation into a GPS time pulse radiator for testing time-stamp accuracy of a radio telescope

The MeerKAT radio telescope in South Africa is required to tag the arrival time of a signal to within 10 ns of Coordinated Universal Time (UTC). The telescope has a local atomic clock ensemble and uses satellite based remote clock comparison techniques to compare the telescope time to UTC. The master clock timing edge is distributed to each telescope antenna via an optical fibre precise time transfer. Although the timing accuracy of the telescope time was measured internally by the telescope, there is a need for an independent method to verify how well each antenna and its associated processing stages are aligned to UTC. A portable GNSS time-pulse radiator (GTR) device for testing the time-stamp accuracy was developed. The GTR was calibrated at the National Metrology Institute of South Africa and laboratory characterisation tests measured its RF timing pulse to be 1.32 ± 0.100 µs ahead of the UTC second. The telescope’s time and frequency reference clock ensemble consists of two hydrogen masers, an ultrastable crystal and GPS disciplined Rubidium clocks. During operation, the GTR radiates a broadband GPS time synchronised RF timing signal at a known distance from the telescope antennas and the corresponding timestamps were compared to the expected value. Recent GTR timing tests performed on one of the MeerKAT antennas showed that the telescope’s generated timestamps associated with the GTR’s RF timing signal coincided with the expected delay of approximately 16 ± 0.1 µs measured from an antenna 4.8 km away from the telescope’s master clock transmitter. Ultimately we used the GTR to verify that the telescope time and UTC were aligned to within 100 ns. Future work is planned to improve the profile of the transmitted signal and timing critical hardware in order to reduce the GTR’s error budget

Conducted EMI Mitigation in Power Converters using Active EMI Filters

Wide bandgap devices enable high power density power converters. Despite the advantages of increased switching frequency, the passive components are still a major bottleneck towards enabling high power density. Among the passive components in the converter, the passive EMI filters are unavoidable to ensure compliance with conducted EMI standards. Active EMI filters help reduce the volume of the passive components and have been around for three decades now. Firstly, this work presents a summary of all the different active EMI filters based on the type of noise-sensing, noise-processing, the type of active circuits used and the type of control methods. This is followed by modeling, design and stability analysis of three different active EMI filters for DM noise attenuation. The first active EMI filter is a conventional active EMI filter. The key bottlenecks to improving performance of the conventional active EMI filter are identified while still achieving volume reduction of passive components. Following this two novel active EMI filters are presented that overcome the bottlenecks of conventional active EMI filter. The second active EMI filter is based on a analog twin-circuit. This novel filter uses a twin-circuit which enables the use of low-voltage surface-mount components for compensation. The third active EMI filter uses zero-phase filtering implemented in an FPGA. While all the filters are demonstrated for differential-mode noise, their use can be extended for common-mode noise attenuation

Power Converters in Power Electronics

In recent years, power converters have played an important role in power electronics technology for different applications, such as renewable energy systems, electric vehicles, pulsed power generation, and biomedical sciences. Power converters, in the realm of power electronics, are becoming essential for generating electrical power energy in various ways. This Special Issue focuses on the development of novel power converter topologies in power electronics. The topics of interest include, but are not limited to: Z-source converters; multilevel power converter topologies; switched-capacitor-based power converters; power converters for battery management systems; power converters in wireless power transfer techniques; the reliability of power conversion systems; and modulation techniques for advanced power converters

Development of novel low noise switch-mode power supply designs for high fidelity audio power amplifiers.

Today, linear power supplies are widely used to provide the supply voltage rail to an audio amplifier and are considered bulky, inefficient and expensive due to the presence of various components. In particular, the typical requirements of linear designs call for physically large mains transformers, energy storage/filtering inductors and capacitors. This imposes a practical limit to the reduction of weight in audio power systems. In order to overcome these problems, Switch-mode Power Supplies (SMPS) incorporate high speed switching transistors that allow for much smaller power conversion and energy storage components to be employed. In addition the low power dissipation of the transistors in the saturated and off states results in higher efficiency, improved voltage regulation and excellent power factor ratings. The primary aim of this research was to develop and characterize a novel low noise switch mode power supply for an audio power amplifier. In this thesis, I proposed a novel balancing technique to optimize the design of SMPS that elevate the performance of converter and help to enhance the efficiency of power supply through high speed switching transistors. In fact, the proposed scheme mitigates the noise considerably in various converter topologies through different mechanisms. To validate the proposed idea, the technique is applied to different converters e.g; PFC boost converter, flyback converter and full-bridge converter. The performance of audio amplifier is evaluated using designed SMPS to compare with existing linear power supply. On the basis of experimental results, the decision has been made that the proposed balanced SMPS solution is as good as linear solution. Due to novelty and universality of balancing technique, it can provide a new path for researchers in this field to utilize the SMPS in all other audio devices by further enhancing its efficiency and reducing system noise