Voltage flicker mitigation with dynamic voltage restorer

This paper is concerned with a pre-flicker compensation strategy adopted by a dynamic voltage restorer (DVR) to mitigate voltage flicker in a power system. The DVR configuration based on flying capacitor multicell (FCM) converter is proposed to mitigate the voltage flicker because of taking the FCM converter advantages such as transformer-less operation and natural self-balancing of flying capacitors voltages. The proposed DVR consists of a series converter on the source-side and a shunt rectifier on the load-side. Choosing this configuration for DVR makes it possible that the shunt rectifier can maintain dc link voltage at a desired value which results in the proper performance of the DVR. Furthermore, the DVR reference voltages calculation method and also, the pre-flicker compensation strategy, which are based on synchronous reference frame (SRF), are adopted as the control strategy. Simulation results, which are provided by PSCAD/EMTDC software, verify that the proposed detection and determination methods are able to detect the voltage flickers and determine the three single-phase reference voltages of DVR as fast as the DVR mitigates the voltage flickers.