Non-iterative, analytic-based passive LCL filter design approach for three-phase two-level power factor correction converters

This paper presents a straightforward LCL filter design method for three-phase power factor correction rectifiers (PFCs). The imposed converter current ripple decides the minimum required converter-side inductance. For third order LCL filter, the grid current ripple can also be studied to find an optimum value for the grid filter inductor to fulfill the grid requirements. Therefore, by limiting the maximum grid current ripple, desired current harmonic attenuation can be achieved. In this paper, a simple damping resistor is connected in series with the filter capacitor. Accordingly, the grid-side filter inductance is calculated as a function of damping resistor and converter current. The rating of the filter capacitor by analyzing the current ripple flowing through the capacitor is achieved and a margin for this capacitor is presented. On the other hand, all the filter parameters are achieved non-iteratively to have acceptable harmonic attenuation. Furthermore, the stability of the converter is studied for different grid conditions. Finally, an LCL filter for a 5 kW silicon-carbide based PFC is designed and validity of the presented method is studied.