Control system for shunt active power filters with adaptive voltage saturation

In this paper a control system for shunt active power filters based on an array of proportional-resonant regulators is developed. An important advantage of this topology is the possibility of selective control, namely the possibility to choose the set of current harmonics that has to be compensated. The main contribution of the paper is an algorithm that adaptively changes the voltage saturation of each regulator in order to preserve the control of the fundamental component of the converter current even if the available voltage is not sufficient to control the current harmonics. At the same time, the algorithm tends to improve the quality of the grid current, because it allocates the DC-link voltage of the active power filter in order to focus on the distorting harmonics of the load in proportion to their significance.