Study On Algorithm Of Detecting Harmonics And Emulation On Shunt Active Power Filter

Application of power conversion and transmission, based on the semiconductor switching element, introduces plenty of harmonics into the electric network,Active Power Filter(APF) then was developed in this background , so study on APF will be meaningful.This paper analyses the APF function principle from the structure form and circuit theory. Then the most effective topology structure is obtained by the comparison between two classical structures which would reduce the capacity in APF, and restraining the harmonics on a large scale.Meanwhile, detecting way as the most important technique in APF has been paid attention on the research under the condition of distortion and unbalance voltage source. Also the proposed method can do well under this circumstance with the utility of two rotation vectors relatively independent of the source phase angle, without changing coordinate, only to obtain the frequency of the Voltage Source, Theoretica- lly double hardware can easily be designed with the parallel structure.For the inner and outer loop controls, in sight of the swift reflection the Hysteresis Current Voltage Space Vector is adopted to minimize the switching frequency for the former. The Bandpass filter for the vent in converter and Lowpass filter applied in demanding current calculation are analyzed in detail and optimized as well as the parameters design of PI regulator used in outer loop control.In the end , the Simulink in Matlab emulation is carried out to confirm what has been designed in above paper to be correct. At the same time the way of this paper will give a reference to the three-phase four-wire APF.