Study On The Parallel Active Power Filter

As the harmonic pollution increasing in power system leading to deterioration of the power quality, Active power filter(APF) has become a focal point of research in the power electronics technology for its superior performance.The parallel active power filter is the one which has been the focus of the APF research,because of its excellent properties.This paper focuses on the three-phase three-wire shunt active power filter technology based on the description of the active power filter.Firstly,the active power filter technology is described,in which the system composition and the working principle are introduced; then a detailed parallel active power filter model is established, which lays the foundation of the harmonic detection and current control analyze.Real-time, high-precision harmonic detection and rapid, accurate harmonic current control is the most two important parts of the active power filter research. This paper analyzes two detection methods based on the instantaneous reactive power theory,and ultimately this paper uses the method based on Park transformation as the harmonic detection method. The dq decoupling control method is used for its common engineering application and the harmonic currents is produced by the SPWM control mode.The detection method and the control algorithm used in this paper are all verified by the simulation.In the practical application of APF, the current loop controller usually uses the PI regulator, but the delay of the system control also limits the performance of the PI controller.In this paper, the lead-lad correction is introduced in the current loop controller in order to enhance the fast tracking capability of the control system, then the simulation result of the APF system with and without correction link is compared to prove the validity of links.Finally, on the basis of these studies, this paper built a three-phase three-wire active power filter protocol.In this device the above-mentioned method are applied to make sure the APF work properly.The experimental results of this device show that the proposed method is fully applicable in the parallel active power filter.