Three-phase four-wire Vienna I rectifier with active filter function including neutral current mitigation

In this paper a Vienna I rectifier is used to achieve active filtering function including the neutral wire current compensation (VR-AF) in a three-phase four-wire system. A linear quadratic with integral action regulator (LQIR) is designed to achieve overall DC bus voltage regulation, harmonics, reactive power and load's neutral current compensations. The converter model is set in the d-q-o rotating reference frame. The latter is augmented with the integral of the q and o components of the (VR-AF) currents and overall DC bus voltage to achieve integral action. The converter is controlled as a multi-input multi-output (MIMO) system and a fixed PWM at 10 kHz is used to generate the gating signals of the power devices. The system is tested for harmonics, reactive power and load unbalance compensation for balanced/unbalanced loads. The simulation results obtained with SPS and Simulink of Matlab show good performance in terms of overall DC bus voltage regulation; line currents shaping, balancing and neutral current mitigation which proved the effectiveness of the adopted control strategy.