Model-based safe coordinated control for centrifugal compressors using evolution strategy

Centrifugal compressors are essential components in fluid machinery systems, often operating under variable load conditions that demand rapid and safe adjustment of control parameters. However, their highly nonlinear and strongly coupled nature introduces significant challenges in maintaining system stability, especially under transient conditions where overshoot can lead to surge or even failure. To address these challenges, this paper proposes a coordinated control strategy that integrates a lumped-parameter model for real-time surge risk assessment with a Covariance Matrix Adaptation Evolution Strategy (CMA-ES) for online optimization of PID controller parameters. The model quantifies the safety margin during setpoint transitions, while the CMA-ES optimizer simultaneously tunes multiple PID gains without requiring system decoupling. The proposed strategy is validated through simulations under three industrially relevant operating modes: constant outlet pressure control, constant mass flow control, and coordinated pressure-flow control. Results demonstrate that the method significantly improves safety and robustness compared to conventional Ziegler-Nichols tuning, effectively suppressing flow and pressure overshoot while maintaining comparable adjustment speed. These findings highlight the strong potential of the proposed approach for practical engineering applications.