Wyniki wyszukiwania - BazTech

1

Predictive-SVM control method dedicated to an AC/DC converter with an LCL grid filter

Dmitruk K.

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2020

|

Vol. 68, nr 5

1049--1056

EN

This paper presents simulation and laboratory test results of an implementation of an infinite control set model predictive control into a three-phase AC/DC converter. The connection between the converter and electric grid is made through an LCL filter, which is characterized by a better reduction of grid current distortions and smaller (cheaper) components in comparison to an L-type filter. On the other hand, this type of filter can cause strong resonance at specific current harmonics, which is efficiently suppressed by the control strategy focusing on the strict control input filter capacitors voltage vector. The presented method links the benefits of using linear control methods based on a space vector modulator and the nonlinear ones, which result in excellent control performance in a steady state as well as in a transient state.

2

Frequency based islanding detection methods in power electronic converters

Dmitruk K., Korzeniewski M., Sikorski A.

Power Electronics and Drives

|

2017

|

Vol. 2 (37), No. 1

27--41

EN

Frequency based methods developed to detect an islanding condition in modern power grid structures have been discussed. The condition may occur in power grid lines to which additional energy sources with power electronic converters have been connected such as solar panels or wind turbines. It is a hazardous operating state for grid workers and devices connected to the islanded part of the grid. Such a state results from the inability to control amplitude and frequency of basic harmonic of the grid voltage. An islanding problem in a power grid with additional small energy sources has been discussed. A basic passive and active islanding detection method have been presented and compared with known frequency based algorithms, namely active frequency drift and active frequency drift with a positive feedback algorithm. Finally, a laboratory test of the proposed islanding detection methods in a three-phase grid with an AC-DC converter has been conducted. To demonstrate differences between the tested methods, total harmonic distortion injected into the output converter current and detection time of islanding state have been measured.

3

Method for Filling and Sharpening False Colour Layers of Dual Energy X-ray Images

Dmitruk K., Mazur M., Denkowski M., Mikołajczak P.

International Journal of Electronics and Telecommunications

|

2016

|

Vol. 62, No. 1

49--54

EN

An X-ray scanning and image processing have a vast range of applications in the security. An image of a content of some package being passed for example to an airplane or to the court house may help to figure out if there are any dangerous objects inside that package and to avoid possible threatening situation. As the raw X-ray images are not always easy to analyze and interpret, some image processing methods like an object detection, a frequency resolution increase or a pseudocolouring are being used. In this paper, we propose a pseudocoloring improvement over material based approach. By addition of the edge detection methods we fill and sharpen colour layers over the image, making it easier to interpret. We demonstrate the effectiveness of the methods using real data, acquired from a professional dual energy X-ray scanner.