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The main objective of the project is further improvement of power quality and efficiency in power electronic converters with an AC/DC stage applying optimum interharmonic energy exchange and multifunctional correction elements. Preliminary investigation verified that to achieve this in conversion circuits using control of ripple power utilization, we have to control not only power conversion of the main dominant ripple harmonic but also power conversion of the other ripple harmonics. Therefore, in three-phase conversion circuits it is useful to control power conversion of the third, sixth, ninth, and twelfth ripple harmonics. In single-phase conversion circuits we have to control power conversion of the second, fourth, sixth, and eighth ripple harmonics. In both cases it enables to eliminate the four dominant low-frequency supply current distortion harmonics and ensure a close-to-unity power factor. It is essential that the rated power of the needed ripple-power converter is only 10 - 12% in three-phase and 20% in single-phase power electronic converters. To verify the feasibility and usefulness of the developed theory, the proposed new schemes, and control algorithms, laboratory prototypes 0.5 - 2 kW will be designed, built, and tested. In Estonia, implementation of the further improvement of power quality and efficiency in power electronic conversion circuits applying optimum control of the ripple power conversion will be most expedient in input AC/DC stages of the converters for time-variable loads such as electric arcs and frequency-controlled variable-speed AC motors. A more general value of the research results will be a more exact theory of the power electronic conversion circuits that enables to enlarge the possibilities to improve the power quality. |