Frequency-Responsive Refrigerator Switching Controller
Sumit Nema, Vivek Prakash, Hrvoje Pandžić
Abstract
Future low-inertia power systems will introduce challenges to system operators to maintain essential grid services such as fast frequency control (FFC). Hence, there is a need for efficient solutions that can provide the desired FFC capability and arrest high rate-of-change-of-frequency (RoCoF). Recent advancements in information and communication infrastructure within the smart grid concept have created new opportunities to optimally control and utilize the immense potential of thermostatically controlled loads (TCLs), such as refrigerators. However, modeling and controlling different types of TCLs to deliver a precise collective FFC response is challenging. In this regard, this paper develops an adaptive decentralized autonomous fuzzy-temperature-frequency (FTF) control strategy to enable refrigerators to alter their power consumption according to variations in the grid frequency. The ability of the proposed FTF controller to modify the power consumption of a population of refrigerators in accordance with a reference power profile is demonstrated through a set of simulations. The results demonstrate the effectiveness of the proposed controller through a strong improvement in the frequency security parameters, i.e. RoCoF and frequency nadir, and with a negligible impact on the thermodynamic performance of refrigerators.