TY - GEN A1 - Schiffer, Johannes A1 - Krishna, Ajay A1 - Raisch, Jörg T1 - A Consensus-Based Control Law for Accurate Frequency Restoration and Power Sharing in Microgrids in the Presence of Clock Drifts T2 - 2018 European Control Conference, (EEC) 12-15 Jun 2018, Limassol, Cyprus KW - Microgrids Y1 - 2018 SN - 978-3-9524-2698-2 U6 - https://doi.org/10.23919/ECC.2018.8550191 PB - IEEE CY - Piscataway, NJ ER - TY - GEN A1 - Schiffer, Johannes A1 - Krishna, Ajay A1 - Hans, Christian A. A1 - Raisch, Jörg A1 - Kral, Thomas T1 - Steady State Evaluation of Distributed Secondary Frequency Control Strategies for Microgrids in the Presence of Clock Drifts T2 - 25th Mediterranean Conference on Control and Automation N2 - Secondary frequency control, i.e., the task of restoring the network frequency to its nominal value following a disturbance, is an important control objective in microgrids. In the present paper, we compare distributed secondary control strategies with regard to their behaviour under the explicit consideration of clock drifts. In particular we show that, if not considered in the tuning procedure, the presence of clock drifts may impair an accurate frequency restoration and power sharing. As a consequence, we derive tuning criteria such that zero steady state frequency deviation and power sharing is achieved even in the presence of clock drifts. Furthermore, the effects of clock drifts of the individual inverters on the different control strategies are discussed analytically and in a numerical case study. Y1 - 2017 UR - http://eprints.whiterose.ac.uk/115991/ U6 - https://doi.org/10.1109/MED.2017.7984168 SN - 2473-3504 SP - 508 EP - 515 ER - TY - GEN A1 - Krishna, Ajay A1 - Schiffer, Johannes A1 - Monshizadeh, Nima A1 - Raisch, Jörg T1 - A consensus-based voltage control for reactive power sharing and PCC voltage regulation in microgrids with parallel-connected inverters T2 - European Control Conference 2019, Naples, Italy N2 - We consider small-scale power systems consisting of several inverter-interfaced units connected in parallel to a common bus, the point of common coupling (PCC), and sharing a joint load. This is a frequently encountered configuration in microgrid applications. In such a setting, two important control objectives are reactive power sharing and voltage regulation at the PCC. In this paper, we first show that the nonlinear equilibrium equations corresponding to the aforementioned objectives admit a unique positive solution. Then, we propose a consensus-based distributed voltage controller which renders this desired unique solution locally asymptotically stable. Finally, control performance is illustrated via a simulation example. Y1 - 2019 SN - 978-3-907144-00-8 SN - 978-3-907144-01-5 SN - 978-1-7281-1314-2 U6 - https://doi.org/10.23919/ECC.2019.8795924 CY - Neapel ER -