A linear decoupling control for a PWM three-phase four-wire shunt Active Power Filter

The presence of current harmonics in the grid causes major problems such as overheating and electromagnetic emissions. Active Power Filters (APF) have been presented as alternative to reduce such harmonics. In this paper, a new constant-frequency control scheme based on the linear decoupling principle is proposed for a shunt three-phase fourwire APF. The APF is used to compensate the current distortion and the reactive power created by a typical industrial load. The elaboration of the control law is based on a small-signal averaged model of the converter, computed in the (d,q,0) synchronous frame. The control scheme consists of multiple-loops regulators that ensure voltage regulation at the DC side of the filter, and current wave shaping at the AC side. The control system is implemented numerically using Matlab/Simulink tool. The performance of the proposed control approach is finally discussed through the obtained simulation results.