Reactive power and imbalance compensation using STATCOM with dissipativity-based control

The paper studies the use of dissipativity-based control for voltage-sourced inverters (VSI) utilized as reactive power and imbalance compensators, e.g., static synchronous compensator (STATCOM). The approach relies on a frequency domain modeling of system dynamics using positive sequence and negative sequence dynamic components. Following the passivity-based procedure, a family of controllers is obtained whose objective is to deal with unbalanced supply voltages, and to perform regulation of AC unbalanced currents. The proposed solution is relevant for high-power VSI inverters. The new controllers include adaptive refinements to cope with parameter uncertainties, and stability and convergence proofs are outlined in all cases. Finally, a series of simplifications and adjustments were explored to reduce the adaptive controllers to PI structures in stationary frame coordinates. The simplified controllers are in a form suitable for implementation, and establish a downward compatibility with standard industrial practice