Power Quality Improvement through a UPQC and a Resonant Observer-Based MIMO Control Strategy

Performance degradation is, in general, regarded as a power quality problem. One solution to recover grid performance is through the application of unified conditioner (UPQC). Although these devices are multi-input/multi-output (MIMO) systems, most common control strategies consist two decoupled controllers, which neglect coupling effects and add uncertainty system. For this reason, paper proposes multivariable resonant observer-based strategy UPQC This method includes all significant between system grid. results stability-based compensator, differs from recently proposed that based on signal calculation cannot assure closed-loop stability. In addition, introduces simplified controller tuning optimal conventional methods without losing performance. It implies can be easily tuned, despite complexity MIMO dynamic model. The with observer verified an experimental setup for single-phase system, obtaining three relevant improvement: (1) harmonics compensation tested total harmonic distortion limit 5%; (2) sags swells mitigation; (3) factor correction, achieving unitary value side.