Stable control method of source current detection type active filter by voltage harmonics feedback

In recent years, voltage distortion on a power distribution line becomes a serious problem. Active filters are known as useful methods for harmonic mitigation methods. A source current detection type current active filter features a simple control system and robustness of its detector gain variation. However, it may cause serious oscillation problems depending on system parameters. This paper proposes a new control method for the active filter to suppress a terminal voltage distortion as well as to prevent the oscillations. The proposed active filter equips a feedback loop of terminal voltage harmonics in addition to the source current detection. When the feedback gain of terminal voltage harmonics is relatively small, the feedback loop works well for preventing the system oscillation problem. As the feedback gain increases, the feedback loop shows effectiveness on suppressing a terminal voltage distortion as well as preventing the oscillation. This paper confirms the operating characteristics of the active filter by some simulation and experimental studies