Skip to Main Content
Currently one-cycle control (OCC) theory is widely used in the control of APF and other FACTS. In contrast to previously proposed methods, there is no need to generate a current reference for the control of the converter current, thus no need for a multiplier and no need to sense the AC line voltage, the APF current, or the nonlinear load current. Only one current sensor and one voltage sensor are used to sense the AC main current and the DC-link capacitor voltage. The DC side active power filter (APF) is shunted at the DC side of rectifier bridge, which has great technical advantages in harmonic suppressing for rectifier load. The circuit topology and basic principle of DC side APF based on OCC are firstly analyzed, and then the estimated formulas and design to determine the main circuit parameters, such as the inductance L, the DC side capacitor C of APF, are given in this paper. The large signal model for DC side APF is derived out based on energy balance, then the design for PI controller about APF's control system is accomplished, and the control system is corrected to be typical II system which can eliminate the steady error and improve the anti-disturbing ability. All of the above analysis and design give the theory basis for designing a DC side APF. The theoretical analysis and design are verified by prototype experiments.