arXiv subjects

Jonathan Brooks

Publications and source records attributed to Jonathan Brooks.

3 recordsLinked to original sources

arXiv2017

Simultaneous identification of linear building dynamic model and disturbance using sparsity-promoting optimization

We propose a method that simultaneously identifies a linear time-invariant model of a building's temperature dynamics and a transformed version of the unmeasured disturbance affecting the building. Our method uses l1-regularization to encourage the identified disturbance to be approximately sparse, which is motivated by the slowly-varying nature of occupancy that determines the disturbance. The proposed method involves solving a convex optimization problem that guarantees the identified black-box model possesses known properties of the plant, especially input-output stability and positive DC gains. These features enable one to use the method as part of a self-learning control system in which the model of the building is updated periodically without requiring human intervention. Results from the application of the method on data from a simulated and real building are provided.

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arXiv2017

Distributed demand-side contingency-service provisioning while minimizing consumer disutility through local frequency measurements and inter-load communication

We consider the problem of smart and flexible loads providing contingency reserves to the electric grid and provide a Distributed Gradient Projection (DGP) algorithm to minimize loads' disutility while providing contingency services. Each load uses locally obtained grid-frequency measurements and inter-load communication to coordinate their actions, and the privacy of each load is preserved: only gradient information is exchanged---not disutility or consumption information. We provide a proof of convergence of the proposed DGP algorithm, and we compare its performance through simulations to that of a "dual algorithm" previously proposed in the literature that solved the dual optimization problem. The DGP algorithm solves the primal problem. Its main advantage over the dual algorithm is that it is applicable to convex---but not necessarily strictly convex---consumer disutility functions, such as a model of consumer behavior that is insensitive to small changes in consumption, while the dual algorithm is not. Simulations show the DGP algorithm aids in arresting grid-frequency deviations in response to contingency events and performs better or similarly to the dual algorithm in cases where the two can be compared.

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arXiv2015

A Decentralized Multi-block ADMM for Demand-side Primary Frequency Control using Local Frequency Measurements

We consider demand-side primary frequency control in the power grid provided by smart and flexible loads: loads change consumption to match generation and help the grid while minimizing disutility for consumers incurred by consumption changes. The dual formulation of this problem has been solved previously by Zhao et al. in a decentralized manner for consumer disutilities that are twice continuously differentiable with respect to consumption changes. In this work, we propose a decentralized multi-block alternating-direction-method-of-multipliers (DM-ADMM) algorithm to solve this problem. In contrast to the dual ascent algorithm of Zhao et al., the proposed DM-ADMM algorithm does not require the disutilities to be continuously differentiable; this allows disutility functions that model consumer behavior that may be quite common. In this work, we prove convergence of the DM-ADMM algorithm in the deterministic setting (i.e., when loads may estimate the consumption-generation mismatch from frequency measurements exactly). We test the performance of the DM-ADMM algorithm in simulations, and we compare (when applicable) with the previously proposed solution for the dual formulation. We also present numerical results for a previously proposed ADMM algorithm, whose results were not previously reported.

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