arXiv subjects

Felix Rey

Publications and source records attributed to Felix Rey.

3 recordsLinked to original sources

arXiv2019

ADMM for Exploiting Structure in MPC Problems

We consider a model predictive control (MPC) setting, where we use the alternating direction method of multipliers (ADMM) to exploit problem structure. We take advantage of interacting components in the controlled system by decomposing its dynamics with virtual subsystems and virtual inputs. We introduce subsystem-individual penalty parameters together with optimal selection techniques. Further, we propose a novel measure of system structure, which we call separation tendency. For a sufficiently structured system, the resulting structure-exploiting method has the following characteristics: (i) its computational complexity scales favorably with the problem size; (ii) it is highly parallelizable; (iii) it is highly adaptable to the problem at hand; and (iv), even for a single-thread implementation, it improves the overall performance. We show a simulation study for cascade systems and compare the new method to conventional ADMM.

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arXiv2019

Decentralized Resource Allocation via Dual Consensus ADMM

We consider a resource allocation problem over an undirected network of agents, where edges of the network define communication links. The goal is to minimize the sum of agent-specific convex objective functions, while the agents' decisions are coupled via a convex conic constraint. We derive two methods by applying the alternating direction method of multipliers (ADMM) for decentralized consensus optimization to the dual of our resource allocation problem. Both methods are fully parallelizable and decentralized in the sense that each agent exchanges information only with its neighbors in the network and requires only its own data for updating its decision. We prove convergence of the proposed methods and demonstrate their effectiveness with a numerical example.

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arXiv2018

Strengthening the Group: Aggregated Frequency Reserve Bidding with ADMM

In a power grid, the electricity supply and demand must be balanced at all times to maintain the system's frequency. In practice, the grid operator achieves this balance by procuring frequency reserves in an ahead-of-time market setting. During runtime, these reserves are then dispatched whenever there is an imbalance in the grid. Recently, there has been an increasing interest in engaging electricity consumers, such as plug-in electric vehicles or buildings, to offer such frequency reserves by exploiting their flexibility in power consumption. In this work, we focus on an aggregation of buildings that places a joint bid on a reserve market. The resulting shared decision is modeled as a large-scale optimization problem. Our main contribution is to show that the aggregation can make its decision in a computationally efficient and conceptually meaningful way, using the alternating direction method of multipliers (ADMM). The proposed approach exhibits several attractive features that include (i) the computational burden is distributed between the buildings; (ii) the setup naturally provides privacy and flexibility; (iii) the iterative algorithm can be stopped at any time, providing a feasible (though suboptimal) solution; and (iv) the algorithm provides the foundation for a reward distribution scheme that strengthens the group.

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