Walter Murray Wonham

This article presents a novel framework for the modeling and scheduling of real-time systems (RTS) processing both sporadic and (multiperiod) periodic tasks, based on nonblocking supervisory control of state-tree structures. Instead of assigning static priorities, a real-time scheduling mechanism, namely priority-free conditionally preemptive scheduling, is used to describe the preemption relation among the tasks processed in an RTS. As a dynamic priority scheduling mechanism, partially preemptive or nonpreemptive earliest-deadline first scheduling is also addressed in this article. Finally, the scheduling strategies are illustrated by real-world examples.

Based on Supervisory Control Theory, this paper introduces a systematic and bottom-up approach to the development and synthesis of a microgrid supervisory control (SC) to formalize a discrete power management strategy. The proposed approach is general, transparent, and rigorous. The envisioned strategy is applied to the islanded mode of operation of an AC microgrid, which includes a battery energy storage system, a solar photovoltaic unit, and a conventional rotating generator as distributed energy resources. The SC is nonblocking and maximally permissive, i.e., it enables transitions among all possible discrete operational scenarios of the microgrid and identifies those that must be avoided. The proposed supervisory control is implemented in an industrial-grade PLCnext hardware platform; the supervisory control performance is evaluated through case studies conducted in a RTDS-based real-time hardware-in-the-loop environment.