Control strategy for a series active filter for the neutral conductor in a building and its installation point

This paper presents control strategy of the series active filter connected to the neutral conductor on the three-phase four-wire distribution system in a building. Harmonic distortion in the building is measured, and it is clarified that the third-harmonic voltage on the upper floor is larger than that on the lower floor because of the influence of line inductances between each floor. The optimum installation point of the active filter in the multi-story buildings is presented. In addition, control strategy for the DC bus voltage in the active filter is studied. Experimental results obtained from a 200-V, 3-kVA laboratory system verify the effectiveness of the series active filter.