Active Power Filtering Under Unbalanced and Distorted Grid Conditions Using Modular Fundamental Element Detection Technique

In this paper, an alternative control technique for producing reference current signal to manage operation of three-phase three-wire parallel-connected active power filter (PAPF) is presented. In the context of generating reference current, time-domain synchronous reference frame (SRF) technique has commonly been recognized to provide the benefit of control simplicity. However, its control structure is rather rigid which restricted its flexibility to be applied in different power system configurations. For instance, SRF technique which is initially designated to work with three-phase system cannot be applied directly to single-phase network without intensive modification to its overall control structure. Hence, in this work, a control technique named as modular fundamental element detection (modular-FED) which exhibits modular structure is proposed, to manage mitigation of harmonic current under unbalanced and/or distorted grid. The design concept of the proposed technique was modeled using MATLAB-Simulink software. Two types of highly nonlinear loads are applied to assess the effectiveness of the proposed modular-FED technique under various unbalanced and/or distorted grids. In-depth comparative analysis with the standard SRF technique is performed to evaluate the benefits of using the proposed technique. The presented simulation findings confirmed superiority of the proposed technique in controlling a PAPF to mitigate harmonics contained in the supply grid.