Design and Control of Single-Phase Controlled VSCs with Saturable Inductor-Based LCL Filters

This paper proposes a current control method and a design procedure for saturable inductor-based LCL filters in single-phase controlled (SPC) voltage-source converters (VSCs). With the presented design method, safe design areas (SDAs) for both converter- and grid-side saturable inductor L-i characteristics are obtained that fulfill design requirements and constraints together with the filter capacitor value. Accordingly, two design examples are reported. The proposed current control algorithm is applied to the designed filters that employ saturable inductors both at the converter- and grid-side. The viability of the proposed algorithms are verified by means of simulations and experiments.