Synchronous machines have traditionally acted as the foundation of large-scale electrical infrastructures and their physical properties have formed the cornerstone of system operations. However, with the increased integration of distributed renewable resources and energy-storage technologies, there is a need to systematically acknowledge the dynamics of power-electronics inverters - the primary energy-conversion interface in such systems - in all aspects of modeling, analysis, and control of the bulk power network. In this paper, we assess the properties of coupled machine-inverter systems by studying an elementary system comprised of a synchronous generator, three-phase inverter, and a load. The inverter model is formulated such that its power rating can be scaled continuously across power levels while preserving its closed-loop response. Accordingly, the properties of the machine-inverter system can be assessed for varying ratios of machine-to-inverter power ratings. After linearizing the model and assessing its eigenvalues, we show that system stability is highly dependent on the inverter current controller and machine exciter, thus uncovering a key concern with mixed machine-inverter systems and motivating the need for next-generation grid-stabilizing inverter controls.
|Original language||English (US)|
|Title of host publication||2017 North American Power Symposium, NAPS 2017|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|State||Published - Nov 13 2017|
|Event||2017 North American Power Symposium, NAPS 2017 - Morgantown, United States|
Duration: Sep 17 2017 → Sep 19 2017
|Name||2017 North American Power Symposium, NAPS 2017|
|Other||2017 North American Power Symposium, NAPS 2017|
|Period||9/17/17 → 9/19/17|
Bibliographical noteFunding Information:
All authors were supported by the U.S. Department of Energy (DOE) Solar Energy Technologies Office under Contract No. DE-EE0000-1583. Y. Lin, B. Johnson, and V. Gevorgian were also supported by the DOE under Contract No. DE-AC36-08-GO28308 with NREL; and S. Dhople was also supported by the National Science Foundation under the CAREER award, ECCS-1453921, and grant ECCS-1509277.