Compensating Strategy Research Of Shunt Active Power Filter

Active power filter (APF) is a kind of power electronic device which is widely used to compensate harmonics and reactive power and to ameliorate power quality problems. Detecting current references from load currents and making the compensator produce anti-phase compensating currents is the basic operating principle of APF, and how to realize it is what the compensating strategy deals with.This paper mainly discusses power theories, software control strategy and hardware components selection which are closely related to APF.In the section of power theories, the characteristics of conventional power theory and instantaneous reactive power theory are discussed. After theoretical analysis and formula development, the features of different power components and their relations with compensating currents are given.In the section of software control strategy, three parts of control strategy, detecting theory, control of DC-side voltage, PWM control, are discussed. The harmonic detecting theories including instantaneous reactive theory, modified instantaneous reactive theory and p-q-r theory are extraordinarily emphasized. The characteristics and differences of the power theories are concluded.In the section of hardware components selection, some brand-new methods about the selection of hardware components in APF are advanced, that is output inductance selection method based on harmonic current analysis, capacitance selection of DC-side capacity and the calculation of parameters values in LCL filter. Simulation results prove the correctness of the hardware components selection methods brought out in the paper.The content of this paper covers some important theories and technological issues closely related to APF. The conclusions and methods brought out in the paper are supported by detailed theoretical analysis and formula developments. The production of this paper has some reference value on the developing of voltage source shunt-APF.