Implementation of Fractional-order Integral-plus-proportional Controller to Enhance the Power Quality of an Electrical Grid

This article integrates a suitable controller to the direct power control algorithm for a shunt active power filter. The conventional proportional-integral (PI) controller is commonly used in DC bus regulation loops because of its advantages in the steady state, but it is limited in the dynamic state. Thus, this article contributes an appropriate controller, the fractional-order-integral-plus-proportional controller. The controller under study extends the integration order of the controller from integer to real order based on fractional calculus theory and Oustaloup continuous approximation. The fractional-order-integral-plus-proportional controller offers a short response time, withstands parameters variations, and deals with external disturbances. To investigate the efficiency and accuracy of the proposed fractional-order-direct power control algorithm considering all robustness tests, an experimental setup was made. The experimental results confirm its high performance in both steady and dynamic states and demonstrate its feasibility and effectiveness. Therefore, the shunt active power filter improves the power quality, corrects the power factor, and reduces the harmonics injected by non-linear loads. Thanks to its high level of power quality, the fractional-order-direct power control could become an interesting alternative for active power filtering.