Direct control of a three-phase active filter on a disturbed network

In order to correct the power factor and limit the flow of harmonics in the source, the effectiveness of active power filters associated to control law is no longer to be demonstrated. Almost all of these methods are designed for a perfect sinusoidal source and do not produce sinusoidal current when the voltages are disturbed. The work developed here concerns active filtering on a perturbed network, that is to say the presence of voltage harmonics at the connection point in addition to a system of unbalanced voltages. A proposed method called DCAP (Direct Control for Active Power) is based on new definition of the sinusoidal active currents desired on the source and assuming a unity power factor under perturbed and polluted system voltages that leads to the DCAP control strategy for active filter. This method considers the active power and the effective value of the fundamental of the voltage is described and its results are compared with those obtained by the p-q theory, the modified p-q theory and the p-q-r method for application on a three-wire disturbed and non-linear load distribution network. The comparison concerns the harmonic distortion rate (THD) of the desired currents obtained on the source as well as Unbalance Factor (UF) of the system of these currents.