AC line voltage controller for grid integration of renewable energy sources

Distributed Renewable Energy generation can affect the power quality of local low voltage distribution grids. Large hydro, wind or solar power plants combined with too weak power distributed infrastructures will generate line voltage increase at the feeding point. A solution for automatic line voltage correction, based on a static AC/AC static converter and a transformer is presented here. Emphasis in the design was put on flexibility, high efficiency, dynamic performance and costs. In case of asymmetric loads, each phase can be controlled individually. In comparison to fully inductive voltage stabilizer, the system has very low or even positive impact on grid impedance and harmonic distortion. The system can be installed anywhere along the line. Thanks to an embedded communication and control interface it can be integrated into smart grid applications. The stabilization is possible by increasing or decreasing the line voltage. Decoupling power electronics and transformer allows modular system sizing in voltage and power ranges. A three-phase single stage power electronics system with its own DSP control system is fully implemented and tested. Results in term of efficiency and dynamic performances are presented in this paper.