Research Of Active Power Filter In Three Phase Four Wire System

With the development of power electronic technology and PWM control technology,controllable and uncontrollable rectifier is applied more and more widely in the power system,but also making the current serious distortion in the power system and the harmonic pollution more and more worse.As China's power supply system uses a three-phase four-wire system,therefore,to research the three-phase four-wire shunt active power filter improving power quality and reducing the harmonic pollution is important.This article from the three phase four wire active power filter main circuit topology view,select an independent modular topology.By deriving the mathematical model expression of the structure under study harmonic detection method based on all the traditional ip-iq theory,then analyze the nominated sub-harmonic detection method,and choose a recursive discrete Fourier harmonic wave extraction method to extract harmonics.Which leads to the DC voltage control characteristic of the low-pass filter according to analysis,to select a suitable filter to the design of the system;in order to track the output current command currents,current loop control strategy is discussed,the choice of a improved proportional resonant controller,and the controller design parameters,based on the design parameters of a sudden sting using discrete pre-correction method of PR controller discrete processing,in order to achieve digital devices.Finally,the combined active power filter hardware and software design,and the use of dual DSPTMS320F28335 and CPLD structures 380V 100kVA modular three-phase four-wire active power filter experimental platform,through the harmonic and reactive power compensation experiment verify the superiority of the current control method has some significance.