This paper proposes a novel harmonic suppression scheme for Uninterruptible Secondary Battery System (USBS). USBS has large capacity of secondary batteries, such as lead-acid or NaS, and it has plural operational modes including local load leveling and unintermptible power supply (UPS). In local load leveling mode, the input current of USBS is desired to be sinusoidal even when the commercial a. c. bus voltage has any harmonic distortions. But some mains circuit configurations cause the increase of harmonic distortion of the input current of USBS. In order to restrain such harmonic distortions, we propose a novel harmonic suppression scheme and the effect of the proposed control scheme is confirmed by the transfer function analysis and experiment.
