Research On Harmonic Suppression Method Of Three-phase Three-wire Parallel Active Power Filter

Constant acceleration of modern industrial has brought about greater demand for highly power equipment,and use of power electronic a lot will reduce the power quality of power grid.A normal operation grid is also affected by harmonics of harmonic components.How to solve the harmonics and power pollution in the power grid have acquired extensive attention.One useful means of solving the problem of harmonics and reactive power pollution is to use the active power filter to eliminate harmonics in the power grid.This paper analyzes several compensation strategies of three-phase three-wire parallel APF,the main contents are as follows:Firstly,introduced the causes and influence of harmonics on the power system,The working principle and circuit structure of active power filter are analyzed.Adopting the three-phase three-wire parallel APF is the main structure,and the mathematical model of the active filter is derived in a three-phase natural coordinate system,and the conclusion is extended in the two-phase rotating coordinate system.Finally,mathematical model acquired in the different coordinate system,which provides conditions for harmonic detection and compensation control in subsequent chapters.By studying the reactive power theory,adopting the p-q detection and improved ip-iq detection on instantaneous reactive power.The accuracy of detection is important,in the improved ip-iq detection,by using a new software phase-locked loop based on a double second-order integrator,ensuring the accuracy of the ip-iq detection method.Several control methods for harmonic compensation are analyzed and compared,including:hysteresis control method,triangular wave control method,deadbeat control method,and space voltage vector control method.Selecting the no-beat control and space voltage vector control with real-time performance and better control effect form the current inner loop control system,and the adopts PI control in outer loop control system.The proposed algorithm is validated by using Matlab simulation and the experimental results demonstrate the effectiveness of the proposed controller.