A combination of DC bias elimination and harmonic suppression technology in single-phase transformer

This paper studies the dc bias elimination and harmonic suppression technology in a single-phase power transformer. A new transformer with function of dc bias elimination based on nano-composite magnetic material was designed and three filter reactors are integrated into the transformer via magnetic-integrated technique. Structural design and electromagnetic design of the transformer is completed and dc bias in transformer core can be eliminated directionally using remanence of the nano-composite magnetic material. Three orders single tuned filters based on the integrated reactors on the filtering side are established. The prototype system experimental results show that dc bias elimination effect was good, and the filter reactors integrated in the transformer have notable effect of harmonic suppression, reactive power compensation and the characteristics of decoupling with other windings, high linearity and less extra covering area.