Abstract
This work proposes a power control strategy based on the linear quadratic regulator with optimal reference tracking (LQR-ORT) for a three-phase inverter-based generator (IBG) using an LCL filter. The use of an LQR-ORT controller increases robustness margins and reduces the quadratic value of the power error and control inputs during transient response. A model in a synchronous reference frame that integrates power sharing and voltage–current (V–I) dynamics is also proposed. This model allows for analyzing closed-loop eigenvalue location and robustness margins. The proposed controller was compared against a classical droop approach using proportional-resonant controllers for the inner loops. Mathematical analysis and hardware-in-the-loop (HIL) experiments under variations in the LCL filter components demonstrate fulfillment of robustness and performance bounds of the LQR-ORT controller. Experimental results demonstrate accuracy of the proposed model and the effectiveness of the LQR-ORT controller in improving transient response, robustness, and power decoupling.
Highlights
Due to the inherent low inertia present in voltage-source inverters (VSI), microgrid control is becoming an important object of study nowadays in order to improve penetration of renewable energy.Microgrid control is generally defined by levels
These results demonstrate that the linear quadratic regulator with optimal reference tracking (LQR-optimal reference tracking (ORT)) performance is more robust for component variation than the classic PR-Droop controller
The LQR-ORT shows lower settling time, less noise, and a smoother transient response under a step reference compared to the PR-Droop controller
Summary
Due to the inherent low inertia present in voltage-source inverters (VSI), microgrid control is becoming an important object of study nowadays in order to improve penetration of renewable energy. The open-loop state-space models for these controllers allow the use of modern control methods such as LQR, Kalman filters, or robust controllers based on H∞ theory These models do not include power sharing dynamics and rely on a higher control level to regulate active and reactive power. A state-space model that integrates V–I and power sharing dynamics for grid connected inverters is presented This model is developed in a synchronous d-q frame to improve active and reactive power decoupling. The active and reactive power dynamics are included in the output equation of the state-space system This type of model allows for using modern control analysis techniques such as singular value diagrams, Nyquist diagrams, root loci, and robustness margins estimations.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
