Ваtrak L. Energy efficient control of shunt active filter of three-phase four-wire power system

The thesis is solved an actual scientific task of creating new and improving existing methods of energy-efficient control of the shunt active filter three phase four wire power system on the basis the development of power theory and design the proportional-vector approach to the formation of a three-phase currents consumed by the source. Based on the rationale of a new formula apparent power four wire power system which takes into account the power loss in the neutral wire, proposed a new algorithm of proportional - vector control of shunt active filter where a support phase voltage vector is formed with partial decrease of zero-sequence component. This provides unity power factor and low loss in the four-wire cable. A new formula for calculating the efficiency of three-phase four-wire power system in nonsinusoidal unbalanced mode with a given load power factor and the known ratio of short-circuit power to the active power loads has been proposed. New analytical conditions of energy efficiency use shunt active filter in a three-phase four-wire power system with considering loss power inverter were obtained. It is shown that most of the existing control strategies shunt active power filters for three phase four-wire power system with repeatedly coordinate transformation matrix are equivalent to formation of in-stantaneous source current vector proportional to the referent voltages vector which coincides with the instantaneous vector of the phase voltages or is its part with improved spectral composition. On the basis of this position control system of three-phase four-wire shunt active filter is offered. It realizes multivariate proportional-vector forming instantaneous current source, novelty items which is confirmed by two patents of Ukraine.