1. Institute of Automatic Control, Electronics and Electrical Engineering, University of Zielona Gora, ul. Prof. Z. Szafrana 2, 65-417 Zielona Gora, Poland
2. Faculty of Electrical Engineering, Wroclaw University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wroclaw, Poland
3. Institute of Physics, University of Zielona Gora, ul. Prof. Z. Szafrana 4a, 65-069 Zielona Gora, Poland
4. Ekoenergetyka—Polska S.A., ul. Nowy Kisielin—Rozwojowa 7A, 66-002 Zielona Gora, Poland