Series voltage restoration under distorted supply voltage condition

In this paper a series connected active compensator is considered. These kind of compensators are a cost-effective solution for the mitigation of supply voltage events. The compensator proposed in the paper allows for voltage waveform restoration, that is compensation of voltage dips, voltage variations, asymmetry and harmonics. A controller which adopts the energy optimised strategy in order to conserve energy stored in the DC side capacitors is also presented. Shift angle between load voltage and supply voltage phasors, which determines injected energy, is computed using only DC voltage signal by means of PI regulator. Effectiveness of the proposed device was tested through numerical simulation, which involved voltage issues caused by a motor start-up and a 1-ph diode bridge load.