86 research outputs found
Practical issues in model-based surge control for centrifugal compressors
The performance and operating range of centrifugal compressors is limited by the occurrence of an aerodynamic instability called surge. This paper deals with the technological barriers for feedback stabilization of full-scale centrifugal compression systems. A dynamic model for a single stage compressor test rig is presented and a surge control strategy is discussed. Then the critical problems of model accuracy and sensor and actuator limitations are discussed. These problems are illustrated with simulation results and experimental data. We conclude by suggesting directions for further work in order to successfully implement active surge control in full-scale applications
Approximate realization with time delay
This paper describes the application of an approximate realization algorithm to dynamical systems with a time delay. First, a well-known algorithm is presented to obtain an approximate realization from an impulse response sequence. Then the limitation that a time delay imposes on the accuracy of this algorithm is discussed, and it is pointed out that time delays should be explicitly taken into account. Therefore, a time delay estimation method is proposed that utilizes the presented approximate realization algorithm. Simulation results show that the method is likely to provide an accurate estimate for the time delay in a dynamical syste
Stability parameter identification for a centrifugal compression system
This paper presents the application of a lumped parameter model to describe the dynamic behavior of a centrifugal compression system including surge. The response of the model is compared with experimental surge measurements from an industrial single stage compressor test rig. A parametric analysis of the model reveals the large influence of the stability parameter on the transient response. However, a good value for this parameter is not easily obtained fromsurge data. Therefore, an identification method is proposed to uniquely determine the stability parameter that is based on an approximate realization algorithm, making use of the fact that the step response of the system has the characteristics of a first order system. Simulation results show that this method canprovide an estimate for the stability parameter of a centrifugal compression system
A high-speed valve for surge control in a centrifugal compression system
This paper deals with the critical problem of actuator limitations for the successful implementation of active surge control. We specify the capacity, bandwidth and allowable time delay for a control valve that can be used to actively suppress surge in a specific full-scale centrifugal compression system. The actuator requirements are obtained from closed-loop simulations with a nonlinear simulation model of the compressor test rig. In order to meet the requirements, a new high-speed valve actuator had to be developed. We present the resulting actuator design and provide test results to illustrate that the control valve meets our design specifications
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