An optimal hierarchical control scheme for smart generation units: an application to combined steam and electricity generation

TL;DR

This paper presents a hierarchical control scheme combining hybrid optimization and model predictive control for efficient management of combined steam and electricity generation units, improving system performance.

Contribution

It introduces a novel hierarchical control framework with a linear parameter varying MPC for optimal start-up and operation of generation units.

Findings

Effective control of coupled energy systems demonstrated in simulations

Enhanced efficiency through optimal start-up trajectory planning

Reduced optimization horizon with intermediate equilibrium state

Abstract

Optimal management of thermal and energy grids with fluctuating demand and prices requires to orchestrate the generation units (GU) among all their operating modes. A hierarchical approach is proposed to control coupled energy nonlinear systems. The high level hybrid optimization defines the unit commitment, with the optimal transition strategy, and best production profiles. The low level dynamic model predictive control (MPC), receiving the set-points from the upper layer, safely governs the systems considering process constraints. To enhance the overall efficiency of the system, a method to optimal start-up the GU is here presented: a linear parameter varying MPC computes the optimal trajectory in closed-loop by iteratively linearising the system along the previous optimal solution. The introduction of an intermediate equilibrium state as additional decision variable permits the reduction of the optimization horizon,while a terminal cost term steers the system to the target set-point. Simulation results show the effectiveness of the proposed approach.