Optimization of Compensator using Grid-impedance Estimation Method by Frequency Sweeｐ

Miniaturization and low cost of PCS (Power Conditioning System) is important for popularization of renewable energy. Especially AC reactor (ACL) is dominant in both volume and cost amount of PCS. If the ACL impedance value becomes smaller than the Grid-impedance between PCS and Grid, it is pointed out that a controllability of PCS has a risk of unstable. In this paper, we propose a control method that PCS itself estimates Grid-impedance and sets optimal control parameters after PCS installation as well. This method can be realized only by adding elements to existing configurations not change the system. As a result, it is able to contribute to downsizing and low cost of the entire PCS.