Design and control of an LCL-filter-based three-phase active rectifier

This paper proposes a step-by-step procedure for designing the LCL filter of a front-end three-phase active rectifier. The primary goal is to reduce the switching frequency ripple at a reasonable cost, while at the same time achieving a high-performance front-end rectifier (as characterized by a rapid dynamic response and good stability margin). An example LCL filter design is reported and a filter has been built and tested using the values obtained from this design. The experimental results demonstrate the performance of the design procedure both for the LCL filter and for the rectifier controller. The system is stable and the grid current harmonic content is low both in the low- and high-frequency ranges. Moreover, the good agreement that was obtained between simulation and experimental results validates the proposed approach. Hence, the design procedure and the simulation model provide a powerful tool to design an LCL-filter based active rectifier while avoiding trial-and-error procedures that can result in having to build several filter prototypes.