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A traditional hybrid-electric propulsion system requires two full-rated converters to convert the electric power from the generator to motor. This brief proposes a method to control the speed of a permanent-magnet synchronous motor (PMSM) receiving power from a doubly fed induction generator (DFIG) and using the generator’s rotor-side converter. This technique can reduce the size and number of converters in a hybrid-electric propulsion system. An integrated model of the system is developed, which is then used to derive the control algorithm. The presentation is simplified by using a complex representation of the dynamic system and of the control law. A voltage and a current command mode are considered and limiting is incorporated to ensure the satisfaction of current constraints. Experimental data show excellent tracking performance of speed references and improved recovery from large load disturbances compared with operation using a synchronous generator. A storage element provides or recovers excess power through the rotor-side converter of the DFIG. [ABSTRACT FROM AUTHOR]

Cascading blackouts are the oldest major unsolved technical problem in power system engineering, highly visible since the Northeast Blackout of 1965 in North America. In this article, we review some cascading blackouts and past work on the problem. New metrics measure network stress to identify and reduce the risk of cascading failures. [ABSTRACT FROM AUTHOR]