Modeling Centrifugal Pump Systems from a System-Theoretical Point of View

This paper suggests a system-theoretical way of modeling simple centrifugal pump systems from a control engineering point of view based on using lumped parameters. First, a basic nonlinear differential equation system is deduced from the known quadratic characteristics of centrifugal pumps and pipelines. Furthermore, an overall electro-hydraulic circuit diagram is presented leading to an appropriate block diagram of the centrifugal pump system. Second, three different cases are analyzed in this electro-hydraulic circuit diagram-idle, short circuit and centrifugal pump with pipeline system. Regarding these cases, applicable linearized transfer functions are identified from measured pressure transients due to defined rotational speed input. It is shown that the system order and structure of the transfer functions, yielding from the theoretical linearization of the nonlinear system, could be successfully reduced and suitably applied to numerical system identification. In a last step, a trial of rough parameter estimation is made with an additional outlook for further estimation methods.