One-cycle control active power filter for three-phase four-wire systems

An advanced active power filter with one-cycle control method for three-phase four-wire system is presented in this paper. First, the main circuit of APF is analyzed. And then the mathematic model of the controller is given. This active power filter employs a four-leg voltage-source inverter and its controller works with one-cycle controlled method. The functions of the proposed APF include the compensation of reactive, harmonic and unbalanced currents in power systems. The one-cycle control method is a new control method with which both the detection of harmonic, reactive and unbalanced current components and the control process for APF are combined. So the control and detecting circuit become simple and has a very good real time property. The theory analysis and simulation results are given finally in this paper. Both theory analysis and simulation results show that the proposed method is effective.