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

The paper investigates the use of dissipativity-based control for voltage-sourced inverters (VSI) utilized as reactive power and unbalance 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 where, due to switching frequency limitations, conventional regulators do not have enough bandwidth to achieve reference tracking. 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 have been 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.