Adaptive Predictive Control of a data center cooling unit

• Published in: Control engineering practice 2021-02, Vol.107, p.104674, Article 104674
• Main Authors: Martínez-García, Fernando, Badawy, Ghada, Kheradmandi, Masoud, Down, Douglas G.
• Format: Article
• Language: English
• Subjects: Adaptive Predictive Controller; Data center; Temperature control; Variable forgetting factor; Variable prediction horizon
• ISSN: 0967-0661; 1873-6939
• DOI: 10.1016/j.conengprac.2020.104674

As server densities increase to support the rising demand for high density computing, traditional room cooling infrastructure is struggling to keep up. Rack-mounted cooling units are increasingly being deployed in data centers. These cooling units are located closer to the heat sources (the servers) which allow them to cool more efficiently than traditional cooling infrastructure. In this work, a Multi-Input Single-Output (MISO) Adaptive Predictive Controller (APC) for rack-mounted cooling units is investigated and implemented using a low-cost general-purpose microcontroller. The proposed APC is implemented using Weighted Recursive Least Squares (WRLS) and a sub-optimal but fast algorithm based on the General Predictive Controller (GPC) approach. These are combined with a variable forgetting factor and variable prediction horizon algorithms. In addition, methods are proposed to handle stability issues arising due to practical hardware limitations. The controller is implemented on a real single rack system and challenges for practical implementation are addressed and illustrated. The proposed APC is also compared (via simulation) to a standard APC with equivalent complexity and a split-range PI controller. The results show that the proposed controller outperforms both the standard APC and the split-range PI controllers with respect to Mean Squared Error (MSE). •A fast and sub-optimal Adaptive Predictive Controller is designed and implemented.•Variable forgetting factor and variable prediction horizon allow higher flexibility.•Implementation can be done in a low-cost and general-purpose microcontroller.•Capabilities to appropriately control a Multi-Input Single-Output system was shown.•Competitive performance is obtained when compared to a standard APC and PI with split range control.