Advanced Techniques for Voltage Flicker Mitigation

This paper presents advanced techniques to mitigate the voltage flicker using inverter based power conditioners. A new control strategy to mitigate the voltage fluctuations, employing the envelope tracking techniques is presented. This control algorithm is appropriate to drive the distribution static compensator (DSTATCOM) to mitigate voltage fluctuations and to regulate the point of common coupling (PCC) voltage. The envelope tracking based control technique has some difficulties in the compensation of unbalanced voltage disturbances. In order to overcome this limitation, another control strategy, based on symmetrical components estimation techniques is introduced in this paper. This strategy is based on compensating both the negative and zero sequences and boosting the positive sequence by using the dynamic voltage restorer (DVR). This action results in compensating voltage flicker and other types of voltage disturbances such as sag, swell, and unbalance. In addition, boosting the positive sequence assists in regulating the load voltage