Title: Assume-guarantee contracts for control of cyber-physical power systems
Laboratory: L2S (Laboratoire des Signaux et Systèmes), UMR 8506 Université Paris-Saclay, CNRS, CentraleSupélec, 91190, Gif-sur-Yvette, France.
Ph.D supervisor: Alessio IOVINE (firstname.lastname@example.org)
Co-supervisor: Adnane SAOUD (email@example.com)
Dates: 3 years, starting fall 2022
Salary: 2000 euro monthly, gross salary
The thesis takes place in the National French ESTHER project funded by ANR.
DESCRIPTION OF THE THESIS:
Assume-guarantee contracts, microgrids, cyber-physical systems, correct-by-design verification
In power systems in general, and in microgrids in particular, existing approaches are not capable of fully exploiting the potential of Cyber-Physical Systems (CPSs) , i.e. physical systems augmented with computation and communication infrastructure making it possible to design highly dynamic systems able to perform efficiently under high uncertainty. Considering microgrids as CPSs is one of the means to facilitate the integration of new components (new storage devices, connections with a new microgrid, Plug&Play of renewables, etc). The physical layer comprising of power/energy infrastructures and the cyber layer comprising control, communication, and computation need to be designed to achieve the overall goals of energy sustenance. Thanks to their reconfigurable structure, CPSs can support the definition of the modern power systems as a flexible and resilient composition of microgrids, thus facilitating the possibility to decompose them in more manageable sub-systems and to favor the integration of new components.
Contract theory [2,3] is a promising framework for rigorous component-based design of highly dynamic distributed systems, thus permitting the correct-by-design definition of cyber-physical power systems (CPPSs). Intuitively, a contract is a formal specification consisting of pairs of assumptions and guarantees. A guarantee describes the task that the component must fulfill when its environment (made of other components and of the external environment) satisfies the associated assumption. Hence, assume-guarantee contracts make it possible to design components that can adapt under various working conditions. Moreover, compositional reasoning makes it possible to prove properties of the global system based on the contracts satisfied by its components.
Classical control approaches for power systems are hierarchical, and consider a de facto separation among the control levels according to the time scale of the considered dynamics [4,5]. Nowadays, the underlying hypothesis are outdated due to the integration of high shares of renewables and energy storage systems, and therefore there is a need for a holistic approach for the control hierarchy. Contract-based design is the promising solution for unraveling the full potential of CPPSs by merging the possibility to have correct-by-design verification of stability and synthesis of multi-level controllers.
In this doctoral work, we will develop a refinement method to empower priority of actions among the control levels of microgrids and permit an efficient vertical arrangement of the control hierarchy while enhancing horizontal coordination among the several physical devices composing the microgrid. We target the following microgrid-oriented results:
• Correct-by-design verification of power systems’ specifications: by considering a microgrid as a CPS in a systematic way since the design phase of the control systems, we will implement a system of systems approach based on contract theory to define the desired specifications with respect to the given components. Then, we will investigate the effects of possible interactions among the components and the optimal configurations with respect to desired requirements.
• Multi-level controller synthesis: given a contract and a component model, synthesize a controller that fulfills the contract. Based on the modeling via contracts and the possible horizontal and vertical interactions, we target considering the hierarchy as a whole for stability purposes and to achieve a global control objective.
In the last year of the thesis, it is expected that the PhD candidate will assist a senior postdoc that will be in charge of implementing the obtained results on experimental tests.
This thesis topic mainly requires good skills in control theory and mathematics. Very good results in the engineering curriculum as well as expertise in the topics related to nonlinear control will constitute strengths to the proposed subject. Knowledge of power systems and electrical grid is not necessary but is a plus.
The proposed subject should lead to the acquisition of strong theoretical skills in the field of control of power systems. In particular, the candidate will become familiar with the modeling of dynamical systems, with control design and with microgrid-oriented control problems. The candidate should also become familiar with Matlab (numerical methods, simulations) or Python.
• A letter of motivation
• Master’s and/or engineering studies evaluations
• A letter of recommendation from the master manager
• The coordinates of two referees
Contact: Send your application by email to
Alessio IOVINE (firstname.lastname@example.org)
Adnane SAOUD (email@example.com)
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