A Novel Dissociated Current Control Technique for Harmonic Minimization in Non-Linear Loads

Abstract

This paper deals with a novel dissociated current control technique for the power quality enhancement. The hybrid filter has its establishment on harmonic minimization and can be used for nonlinear loads. The reference current extraction is by means of stationary “abc” reference frame and then transformed to orthogonal “dq” transformation. A proportional-integral control system is derived through linearization of nonlinear shunt active filter system model, so that the task of current control dynamics and dc capacitor voltage dynamics become dissociated. The Proportional Integral controllers are used to control the dc bus link voltage and to control the shunt hybrid filter input currents. The currents track closely their references so that the shunt hybrid filter behaves as a quasi-ideal current source connected in parallel with the load. It compensates the reactive power and harmonic currents required by the non linear load, thereby achieving sinusoidal supply currents in phase with supply voltage both dynamic and steady-state conditions. The shunt hybrid filter is implemented with three phase current controlled Voltage Source Inverter for compensating the current harmonics by injecting equal but opposite  filter currents. The Shunt hybrid filter is more efficient in harmonic minimization. The proposed shunt hybrid filter maintains the THD threshold as recommended by IEEE-519 standards. This proposed technique is implemented in MATLAB simulink software

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