Comparison of Three Phase 4-Leg Shunt Active Power Filter using dq, Indirect and Maximum Control Method - Bălănuță, Ciprian; Gurguiatu, Gelu; Munteanu, Toader; Fetecău, Grigore (The Annals of “Dunarea de Jos“ University of Galati. Fascicle III, Electrotechnics, Electronics, Automatic Control, Informatics, 2011)