Coordinating regulation and demand response in electric power grids using multirate model predictive control

We propose a framework for reducing demand-supply imbalances in the grid, by jointly controlling both the supply-side electric power regulation together with the demand-side energy consumption by residential and commercial consumers demand response. We focus on performance improvements that arise from the complementary dynamics: regulation allows for frequent control updates but suffers from slower dynamics; demand response has faster dynamics but does not allow as frequent control updates. We propose a multirate model predictive control (MPC) approach for coordinating the two services, and we refer to this coordinator as an aggregator. Multirate MPC captures the varying dynamics and update rates, and nonlinearities due to saturation and ramp rate limits, and a total variation constraint limits the switching of the demand response signal. Our approach can operate with both direct reference or indirect market price based imbalance signal. Numerical examples are presented to show the efficacy of this joint control approach.