Active power filter based on novel current reference calculation

An active power filter (APF) based on a new method of determining the current reference is presented in this paper. In the proposed method of getting the current reference, two aspects are covered, i.e., the phase and the amplitude of the reference. For the former, a sliding Fourier analysis approach is employed, where the Fourier analysis is carried out in a sliding coordinate system, eliminating the accumulated error caused by the difference between the internally generated time reference and the line cycle when discretizing the Fourier algorithm. And the latter is determined from the viewpoint of energy balance. The proposed method features in its software synchronization, making it unnecessary for an extra synchronization circuit to the grid. The proposed active power filter works well under various load conditions, especially in the case of a distorted or unbalanced supply. Experimental results obtained from the prototype confirm the feasibility of the proposed method.