AN IMPROVED DSTATCOM TOPOLOGY TO COMPENSATE NONLINEAR LOADS

Abstract

Traditionally, static capacitors and passive filters have been applied to improve power quality (PQ) in a distribution system. However, those normally have issues such as constant compensation, system parameter dependent outcome, and possible resonance with line reactance. A distribution static compensator (DSTATCOM) has been proposed in the literature to triumph over those drawbacks. It inserts reactive and harmonics element of load currents to make supply currents balanced. Normally, the dc-link voltage is maintained at lots higher value than the maximum value of the phase-to-neutral voltage in a 3-section 4-wire system for excellent compensation (in a 3-section 3-wire system, it is higher than the phase-to-phase voltage). But, a higher dc-link voltage will increase the rating of the VSI, makes the VSI heavy, and effects in better voltage rating of insulated gate bipolar transistor (IGBT) switches. It leads to the growth in the cost, size, weight, and power rating of the VSI.