Energy

Charging Ahead on the Transition to Electric Vehicles with Standard 120V Wall Outlets

Saxena, Samveg
MacDonald, Jason
Moura, Scott
2015

Electrification of transportation is needed soon and at significant scale to meet climate goals, but electric vehicle adoption has been slow and there has been little systematic analysis to show that today’s electric vehicles meet the needs of drivers. We apply detailed physics-based models of electric vehicles with data on how drivers use their cars on a daily basis. We show that the energy storage limits of today’s electric vehicles are outweighed by their high efficiency and the fact that driving in the United States seldom exceeds 100km of daily travel. When accounting for these...

Recursive Parameter Estimation of Thermostatically Controlled Loads via Unscented Kalman Filter

Burger, Eric M.
Moura, Scott J.
2015

For thermostatically controlled loads (TCLs) to perform demand response services in real-time markets, recursive methods for parameter estimation are needed. As the physical characteristics of a TCL change (e.g. the contents of a refrigerator or the occupancy of a conditioned room), it is necessary to update the parameters of the TCL model. Otherwise, the TCL will be incapable of accurately predicting its potential energy demand, thereby decreasing the reliability of a TCL aggregation to perform demand response. In this paper, we investigate the potential of an unscented Kalman filter (UKF...

Privacy-Preserving Dual Splitting Distributed Optimization with Application to Load Flattening in California

Belletti, Francois
Le Floch, Caroline
Moura, Scott
Bayen, Alexandre M.
2015

This article presents a dual splitting technique for a class of strongly convex optimization problems whose constraints are block-wise independent. The average-based input in the objective is the only binding element. A dual splitting strategy enables the design of distributed and privacy preserving algorithms. Theoretical convergence bounds and numerical experiments show this method successfully applies to the problem of charging electric devices so as to even out the daily energy demand in California. The solution we provide is a privacy enforced algorithm readily implementable in a...

Distributed Optimal Charging of Electric Vehicles for Demand Response and Load Shaping

Le Floch, Caroline
Belletti, Francois
Saxena, Samveg
Bayen, Alexandre M.
Moura, Scott
2015

This paper proposes three novel distributed algorithms to optimally schedule Plug-in Electric Vehicle (PEV) charging. We first define the global optimization problem, where we seek to control large heterogeneous fleets of PEVs to flatten a net Load Curve. We demonstrate that the aggregated objective can be distributed, via a new consensus variable. This leads to a dual maximization problem that can be solved in an iterative and decentralized manner: at each iteration, PEVs solve their optimal problem, communicate their response to the aggregator, which then updates a price signal. We...

Estimation and Control of Battery Electrochemistry Models: A Tutorial

Moura, Scott J.
2015

This paper presents a tutorial on estimation and control problems for battery electrochemistry models. We present a background on battery electrochemistry, along with a comprehensive electrochemical (EChem) model. EChem models present a remarkably rich set of control-theoretic questions involving model reduction, state & parameter estimation, and optimal control. We discuss fundamental systems and controls challenges, and then present opportunities for future research.

Building Electricity Load Forecasting via Stacking Ensemble Learning Method with Moving Horizon Optimization

Burger, Eric M.
Moura, Scott J.
2015

The short-term forecasting of building electricity demand is certain to play a vital role in the future power grid. Given the deployment of intermittent renewable energy sources and the ever increasing consumption of electricity, the generation of accurate demand-side electricity forecasts will be valuable to both grid operators and building energy management systems. The literature is rich with forecasting models for individual buildings. However, an ongoing challenge is the development of a broadly applicable method for electricity forecasting across geographic locations, seasons, and...

Gated Ensemble Learning Method for Demand-Side Electricity Load Forecasting

Burger, Eric M.
Moura, Scott J.
2015

The forecasting of building electricity demand is certain to play a vital role in the future power grid. Given the deployment of intermittent renewable energy sources and the ever increasing consumption of electricity, the generation of accurate building-level electricity demand forecasts will be valuable to both grid operators and building energy management systems. The literature is rich with forecasting models for individual buildings. However, an ongoing challenge is the development of a broadly applicable method for demand forecasting across geographic locations, seasons, and use-...

Alternative Control Trajectory Representation for the Approximate Convex Optimization of Non-Convex Discrete Energy Systems

Burger, Eric M.
Moura, Scott J.
2016

Energy systems (e.g. ventilation fans, refrigerators, and electrical vehicle chargers) often have binary or discrete states due to hardware limitations and efficiency characteristics. Typically, such systems have additional programmatic constraints, such as minimum dwell times to prevent short cycling. As a result, non-convex techniques, like dynamic programming, are generally required for optimization. Recognizing developments in the field of distributed convex optimization and the potential for energy systems to participate in ancillary power system services, it is advantageous to...

Piecewise Linear Thermal Model and Recursive Parameter Estimation of a Residential Heating System

Burger, Eric M.
Perez, Hector E.
Moura, Scott J.
2016

Model predictive control (MPC) strategies show great potential for improving the performance and energy efficiency of building heating, ventilation, and air-conditioning (HVAC) systems. A challenge in the deployment of such predictive thermostatic control systems is the need to learn accurate models for the thermal characteristics of individual buildings. This necessitates the development of online and data-driven methods for system identification. In this paper, we propose a piecewise linear thermal model of a building. To learn the model, we present a Kalman filter based approach for...

Integrated Optimization of Battery Sizing, Charging, and Power Management in Plug-In Hybrid Electric Vehicles

Hu, Xiaosong
Moura, Scott J.
Murgovski, Nikolce
Egardt, Bo
Cao, Dongpu
2016

This brief presents an integrated optimization framework for battery sizing, charging, and on-road power management in plug-in hybrid electric vehicles. This framework utilizes convex programming to assess interactions between the three optimal design/control tasks. The objective is to minimize carbon dioxide (CO2) emissions, from the on-board internal combustion engine and grid generation plants providing electrical recharge power. The impacts of varying daily grid CO2 trajectories on both the optimal battery size and charging/power management algorithms are analyzed. We find that the...