Modified FBD Method in Active Power Filters to Minimize the Line Current Harmonics

Harmonic line currents due to nonlinear loads cause nonsinusoidal grid voltages in electrical power systems. Shunt active power filters (SAPFs) can be employed to improve the system efficiency but their design must consider nonsinusoidal conditions. The Fryze, Buchholz, and Depenbrock method has been applied to controllers in SAPFs, allowing the compensation of the load nonactive power. A drawback of this method is a resultant line current with harmonic components which contributes to maintain the grid voltage distortion. This letter proposes a new definition of conductance for SAPF controllers in case of nonlinear loads and nonsinusoidal grid voltages which minimize the line current distortion