Dynamic Analysis and State Feedback Voltage Control of Single-Phase Active Rectifiers with DC-Link Resonant Filters

Single-phase active rectifiers exhibit an inherent strong second-order current harmonic on their DC-link. The latter is often undesirable from a load point of view and is therefore chosen to be eliminated. A common method is the use of a resonant passive LC filter tuned at this frequency, which increases the order of the system, posing certain difficulties for the voltage control design. This paper presents a comprehensive analysis of the DC-link dynamics. The equations are linearized by means of small variations and a respective closed-loop regulator is formed utilizing the partial state feedback control theory for pseudo-continuous systems. The control output is fed to an inner current regulator, following the well-known cascaded loop method. The stability of the proposed controller is validated throughout the whole operating point regime and its robustness against system parameter variations is evaluated. A comparison with a conventional controller proves the advantages of the utilized method. The theoretical analysis is verified by means of simulations as well as real-time implementation on an experimental laboratory setup.