Study On Parallel Active Power Filter Based On FFT Technology

In order to prevent the nonlinear and reactive load caused by harmonic pollution and reactive power loss is not necessary for the power grid,the shunt active power filter because of its superior performance,high power factor compensation,and other power grid load resonant has attracted many scholars and researchers.Starting from the topology classification of active power filter,the superiority of shunt active power filter is described.Based on the topology and working characteristics of shunt active power filter,the mathematical model of the system is summarized.For the extraction of harmonic and reactive components,this paper describes the use of instantaneous reactive power theory and fast Fu Liye transform harmonic detection in detail.For the design of control strategy,in order to make the current active power filter has better performance,this article uses proportional resonant controller to harmonics of static control,improved proportional integral control of straight flow only zero error tracking defects.Proportional integral control can only be for a harmonic control based on this topic in order to simplify the control structure,saving system resources,design a fast Fourier transform based on harmonic extraction,then according to the composition and content of the harmonic,the design of current loop parallel proportional resonant controller adaptive control.The design of adaptive proportional resonance controller based on fast Fourier transform is described in detail.For the system to work in the harmonic component of large,in order to avoid the effects of possible interference on the traditional voltage phase-locked loop,design the synchronization software phase-locked loop based on proportional integral control,and introduces the principle of coordinate transformation and in synchronous rotating coordinate system on voltage vector phase-locked tracking design.In order to verify the correctness of the control strategy,the simulation of control system based on Matlab/Simulink is carried out,and the overall simulation structure is given,and the components of each simulation module are elaborated in detail.The result waveform of the compensation current,phase locked loop and harmonic spectrum is given,and the correctness of the principle of the whole design is verified.The hardware circuit design and hardware experimental platform are built,and the hardware circuit diagram and detailed design idea of each module of control system and main circuit system are given.And based on the DSP28335 of TI company,the software system is designed,and the program block diagram of each software module is given.The experimental prototype of active power filter is verified.The practical waveforms of phase-locked loop,voltage and current transient process and steady-state operation of each part are given,and the detailed description is given to verify the correctness and design idea of the design,and the feasibility of the control principle.