Abstract: The essential for harmonic independent control of active power filters（APF） contains three functions as follows: 1) selective harmonic compensation; 2) setting compensation factor for the selective harmonic; 3) zero steady state error compensation for the selective harmonic. This paper presents an improved control structure consisting of selective harmonic detection and centralized current loop. The structure includes two modes: selective harmonic compensation and all harmonic compensation, which is based on comparison of four traditional schemes in terms of the control structure. In addition, taking the control structure consisting of selective harmonic detection under the multiple rotating reference frame and the single PI current loop for example, this papers gives the method for steady state error correction qualitatively and quantificationally, which employs frequency response characteristics. The proposed method has some advantages, such as the simple control structure, easy parameter adjustments and superior stability. Theoretical analysis is supported by comparative simulation and experimental results.