Decomposition-Based Control Co-Design of Energy Systems Using Graph Models

Efficient design and operation of energy systems are crucial for minimizing wasted energy, lowering greenhouse gas emissions, and minimizing energy-related costs for individuals and businesses. Control co-design techniques have been applied to energy systems to optimize them. Control co-design techniques are conventionally formulated to optimize an entire energy system in one problem formulation. However, as energy systems can be composed of many subsystems, this can result in optimization problems that are near intractable and computationally expensive. Therefore, it can be beneficial to decompose the control co-design formulations. A decomposition-based control co-design framework is developed using graph-based dynamic models and augmented Lagrangian coordination techniques. The graph-based modeling framework is based on conservation of energy and can be applied to multiple energy domains, making them versatile and able to capture the interactions among components. This framework is applied to optimize a notional aircraft fuel thermal management system. The decomposition-based control co-design approach is shown to result in a design that performs within 1.3% of the optimized all-at-once approach design. This approach leads to a component-wise system optimization with results near the optimal design.