A Robust Control Strategy for Regulating DC-Link Voltage of Active Power Filter without Load Current Measurements

This paper presents a robust control strategy for regulating dc-link voltage of shunt active power filters without load current measurements. The dc-link of these schemes suffers when a load variation occurs. To compensate these effects a robust control strategy based on an adaptive pole placement control strategy integrated to a variable structure control scheme VS - APPC is proposed. In this control strategy the dc-link voltage regulator generates the filter reference currents based on the system active power balance. With this control scheme, rises or drops on the dc-link voltage due to the load variation are significantly reduced. The effectiveness of the proposed control strategy is demonstrated by comparisons with standard control schemes implemented with proportional-integral PI or PI controller associated with feed-forward scheme. Experimental results are also carried out to demonstrate the advantages of the proposed method.