Abstract: This paper deals with improving the voltage quality of loads from voltage sags using dynamic voltage restorer (DVR). The higher active requirement associated with pulse width modulation (PWM) has caused a substantial rise in size and cost. The existing control strategies either mitigate the pulse width modulation or improve the utilization of dc link energy reducing the amplitude of injected voltage. In this paper on enhanced sag compensation strategy is proposed it mitigate the overall sag compensation time. An analytical study shows that the proposed method significantly increases the DVR support time compared with existing PWM method. This enhancement can also be seen as a considerable reduction in dc link capacitor sixe for new installation. The performance of the proposed method is evaluated using simulation study and finally verified experimentally on a small prototype model.
Keywords: Dynamic voltage restorer (DVR), voltage phase jump compensation, voltage sag compensation, Pulse Width Modulation.