Shunt Active Power Filter

Shunt active power filters have been introduced as a way to overcome the power quality problems caused by nonlinear and reactive loads [9, 14, 23]. These power electronics devices are designed with the goal of obtaining a power factor close to 1 and achieving current harmonics and reactive power compensation [5, 6, 15]. The usual approaches [5, 15] for the control of shunt active filters are based on two hierarchical control loops: an inner one that assures the desired current and an outer one in charge of determining its required shape and the appropriate power balance as well. The control structure followed in this Chapter is the one in [7], in which the current controller is composed of a feedforward action that provides very fast transient response, and also of a feedback loop which includes an odd-harmonic repetitive control that yields closed-loop stability and a very good harmonic correction performance. In turn, the outer control law is based on the appropriated computation of the amplitude of the sinusoidal current network and, aiming at a robustness improvement, this is combined with a feedback control law including an analytically tuned PI controller.