Design And Research Of Three-phase Four-leg Active Power Filter Based On DSP

With the rapid development and wide application of power electronics technology,the promotion of industrial development and social progress can't be denied,but the pollution of power system and power quality also can't be ignored.Under the background of the three-phase four-wire system connection in low voltage distribution network in our country,the three-phase four-wire active power filter is becoming one of the most advanced methods to solve the power quality problem.Meanwhile,with the rapid development of power switching devices and the wide application of modern intelligent control theory,the active power filter compensation technology is becoming more and more mature.In this paper,the main circuit topology of three-phase four wire shunt active power filter(SAPF),the detection algorithm of compensation command current and the output current tracking control algorithm are studied and designed.In this paper,the three-phase four wire shunt active power filter is studied and designed based on the main circuit topology of four legs.The mathematical model of the system in the stationary abc and ??O coordinate system is established and the coupling relationship among the parameters affecting the system performance is analyzed.What's more,the compensation command current detection algorithm is proposed based on the position coordinates of the voltage rotation vector,and the calculation formula of instruction current is confirmed.Meanwhile,based on the single-phase half-bridge inverter circuit and the direct current control method,a fast tracking control method for the output current of four-leg active power filter is proposed and the theoretical derivation of the 8 channel PWM pulse width is derived.This control algorithm can reduce the complexity of the control algorithm and save the CPU resource space.In order to verify the correctness of the proposed detection algorithm and control strategy,this paper carried out the implementation of the simulation system of the four-leg shunt active power filter(SAPF),and gives the corresponding hardware and software design based on the MATLAB/Simulink simulation platform.Finally,a capacity of 30KVA modular test prototype which uses TMS320F28335 DSP as the main control unit was designed and built.The simulation and experimental results show that the proposed control algorithm is effective and has the advantages of simple control and good real-time performance.