A Dynamic Voltage Restorer with the Functions of Voltage Restoration,Regulation Using Reactive Power,and Active Filtering

An operation approach of a single-phase dynamic voltage restorer using the functions of voltage restoration, voltage regulation using reactive power, and an active filter is proposed in this article. The regulation using reactive power function is used to compensate swells and some sag cases, if the load power factor allows its application. The use of reactive power means that no average energy is provided from or absorbed by the energy storage. This is a significant advantage, since the equipment can compensate swells without the need of regeneration of the oversizing of the DC link or of dissipation means, and it can compensate sags without using stored energy. For the sag cases where regulation using reactive power is not possible to apply, the classical voltage restoration function using the active power of the energy storage to compensate is activated. In addition to these functions, permanently and simultaneously with any of them, the active filter function operates to compensate the voltage harmonic distortion. The proposed approach is evaluated in simulation under a 16.6-kVA scheme and proved experimentally in a 2-kVA voltage restoration prototype.