Control mechanism of parallel active power filter under different compensation objectives

Regular control of parallel active power filter (PAPF) based on the p-q theory is studied in this paper. After evolutional reduction of the control diagram and mathematic derivation of the p-q theory, a generalized conclusion is drawn: regular control scheme could be regarded as a composite control with feedback of dc-link voltage and feedforward of the fundamental load current; under different compensation objectives, the feedforward components are different, maybe the whole fundamental load current or its active or reactive components. Moreover, two key function modules of the p-q theory are explained in a fresh view. Simulation and experimental results based on the proposed composite control are shown to confirm the validity of the analysis.