Electromagnetic compatibility (EMC) standards for an accredited test laboratory require that the measurement uncertainty of the measuring instruments be characterized. The CISPR 16-4 standard gives guidance to the magnitude of this uncertainty, but no method of characterization. This thesis describes a method to perform this characterization on a conducted emissions measurement system, taking advantage of full system analysis techniques to reduce the uncertainty to exceptionally low levels. In addition, a framework is introduced whereby uncertainty can decomposed into its constituent parts such that the laboratory operator can identify methods to improve the systems performance.

This thesis comprises modeling and simulation of an AC-DC converter (Battery charger). An AC-DC converter may cause a high frequency distortion in the electrical power network or augment the existing distortion caused by other devices connected to the network. The goal is to design a controller for suppressing this noise at a reasonable level. We hope the thesis can be considered as a step forward to solve the original problem. One needs an accurate model of the AC-DC converter, to design such a controller. This study tries to clarify the effects of theline inductance on the performance of the converter by modeling and simulating the converter during the commutation time. The idea is to model and simulate the converter for two different conditions; first in the Normal condition by neglecting the effect of line impedance, second in the Commutation condition by considering the effect of the line impedance on commutation of the diodes. One can perform a complete simulation of the converter with combining these two models. The thesis deals with AC-DC converters, Hamiltonian-port modeling, simulation and MATLAB programming using the functionality of the S-function and SIMULINK.

Yes / This paper proposes a new index to determine the static voltage stability of the load buses in a power network for certain operating conditions and hence identifies load buses which are close to voltage collapse. The proposed index is formulated from the quadratic equation derived from a two-bus network and is computed using the apparent power and the line impedance. The proposed index shows how far the load buses from their voltage stability limit and hence the most sensitive bus can be identified according to maximum loadability. 14 bus IEEE reliability test system is used to study the performance of the proposed index for its validity. A comparison is also made between proposed index and some other indices found in the literature. The results are discussed and key conclusion drawn.

Electromagnetic Interference (EMI), primarily common mode (CM), is problematic in a wide range of electronic circuits due to its propensity to radiate, particularly in high power applications. It is routine for much effort and resources to be dedicated to its characterization and reduction as EMI compliance is a requirement for most electronic systems and devices, including power electronics. Many well-known factors contribute to a system’s EMI performance including intentional coupling from system components as well as unintentional coupling from parasitics. Sources of intentional coupling may include Y-capacitors intended to mitigate EMI as part of a filter. Unintentional coupling is more elusive and can exist throughout the system in PCB layout, cabling, load construction, and internal to components such as inverter bridges. Lesser-known contributions to EMI performance irregularities can be EMI filter asymmetries, switching asymmetries, line impedance variances, and galvanic coupling from the metrology intended to measure EMI. It is critical to understand these contributors to facilitate designs with optimal EMI performance. EMI filters are often added to designs with no consideration to asymmetries in construction and component tolerances. This proposal evaluates the impact to CM currents in cases of coupling or leakage inductance imbalances of a CM choke. Similarly, CM currents are also evaluated for cases when EMI filter Y-capacitor imbalances span the components tolerance band. Also analyzed are switching asymmetries in a typical converter topology to understand EMI impact and evaluate potential benefits if intentional asymmetric switching is applied. A practical method is introduced to measure line impedance upstream of devices under test as line impedance variation can impact the performance of EMI filter design. However, few documented practices exist to measure line impedance without specialized instrumentation. Finally, this work proposes a streamlined method for conducted emissions evaluation employing an oscilloscope, differential voltage probes, and post-processing software implemented in MATLAB. This method eliminates unintended metrology ground coupling that can significantly impact EMI measurements and minimizes risk of instrumentation damage particularly in high power systems.

This work deals with interfering signals and noises, possibilities of their measurement, their reduction and afterwards with design of LISN. The theoretical part analyzes formation of interfering signals, their types, with possible measuring instruments for each type of these signals and their properties. In framework of practical part LISN for long-term load of 5A, frequency range from 150 kHz to 30 MHz, with possibility to measure symmetrical and asymmetrical noise separately and also with possibility to switch to normal mode of LISN was developed. For better results LISN was realized as two stage LC filter.