Research On Active Power Filter Based On Adaptive Hysteresis SVPWM Control Method

With the widely application of power electronic devices in utility grid,such as switching power supply,uninterruptible power supply(UPS),variable-frequency drive,etc.,which have generated numerous harmonic currents and consumed reactive power,so the power quality of the grid is decreased.Active power filter(APF)is a power electronic devices,which can be used to suppress harmonics and compensate reactive power,then to improve the power quality.Analyses are made to detection method for harmonics and reactive currents,and current tracking control method mainly from the following objectives.Firstly,this dissertation presents an introduction to the mechanism,perniciousness for production and living,and some compensation methods of harmonic currents.And for active power filter,the basic principle,system structure,categories,some detection methods for harmonics and reactive current and current tracing control methods are analyzed.Then,based on three-phase instantaneous reactive power theory,the p-q method and ip-iq method are analyzed.And DC-link voltage control is a key technology of APF system,this dissertation also study the DC-link voltage stability based on ip-iq method.Furthermore,the detection method for harmonics and reactive current with three-phase source currents and correction link is researched,which can solve the problem of parallel resonance between HPF(High Pass Filter)and source impedance,and improve compensation performance compared with the conventional ip-iq detection method based on three-phase load currents for parallel hybrid active power filter system.Besides,an adaptive hysteresis SVPWM current tracing control method is proposed in this dissertation.The proposed method can fundamentally overcome the drawbacks of conventional space-vector hysteresis current control(SVHCC)method.Three-phase compensation currents can quickly and accurately track the reference currents,and the switching frequency is approximately constant for APF system.The proposed current tracking control method is researched through calculation of adaptive hysteresis bandwidth,identification the sectors of reference voltage vector and current error vector,and selection appropriate output voltage vector.Base on the aforementioned analyses and researchs,simulation model of three-phase four-wire parallel hybrid active power filter system in MATLAB/Simulink is developed.And the experimental prototype is designed based on DSP28335.Both the results of simulations and experiments demonstrate the APF system based on the detection method for harmonics and reactive current and the proposed current tracking control method have the ability of suppressing the harmonics and compensating reactive current.