A soft start-up scheme for DC-link voltage pumping in active power filter

The operation of active power filter requires that the DC-link capacitor voltage is pumped up reliably without current inrush. In this paper, a smooth and reliable, or soft start-up scheme for DC-link capacitor voltage pumping is proposed, by inserting a resistor in series with the inductor of LCL-Filter on the grid side. The resistor serves to limit the electric current, and at the same time improve the control system characteristics. The system model with the resistor in circuit is analyzed, and simulation and experimental results are provided to demonstrate the feasibility of the proposed scheme.