Alf Johansson

A Simulation-based Spectral Technique for Power Quality and EMC Design of an Independent Power System

A novel simulation-based spectral technique for power quality and electromagnetic compatibility (EMC) design of an independent electrical power system (EPS) has been proposed. Power filter optimization problem has been formulated to provide full solution of the electric power quality and conducted EMI problems in the EPS. The spectral technique has been implemented within a CAD tool. An example of power quality and EMC design has been provided for an independent EPS where an AC power source generates a power, which is comparable to the consumed power, and an additional power filter is calculated for an electronic product including a switch-mode power supply. Current and voltage spectra calculations have been verified with a block-oriented simulation program Simulink. Numerical experiments revealed a number of important features of the proposed spectral technique.

Multi-disciplinary approach to design of a power electronics module for harsh environments

A set of experimental and computer simulation methods has been applied to reliability analysis of a newly designed resin transfer molded power electronics module for automotive applications, comprising the glass-fiber epoxy multi-layer PCB, populated with various electronic packages. Evaluation of thermo-mechanical stability, determination of moisture ingress, and testing the adhesion quality between the molding compound and the module PCB have been performed along with investigation of heat transfer paths in the module. The experiments in harsh environments have revealed thermo-mechanical stability and acceptable moisture ingress for the module test samples with relatively large BGA components on the glass-fiber epoxy PCBs of different thickness and different solder mask types. Thermal images of the module have been obtained and the CFD model was created and validated with temperature measurements in power-on tests. Extreme heat dissipation modes have been studied by modeling.