Levon Gevorkov

PLC-Based Pressure Control in Multi-Pump Applications

Abstract The paper is devoted to the centrifugal pumps represented the most popular type of pumping equipment used in different areas. The pressure control approach for variable speed driven (VSD) parallel connected centrifugal pumps is reported. The goal of the study is optimization of some quality indices, such as efficiency, consumed power, productivity, energy carrier temperature, heat irradiation, etc. One of them – efficiency – has been studied in the paper more carefully. The mathematical model of pumping process is discussed and a vector-matrix description of the multi-pump application is given. The program-based pressure control system is developed which productivity is changed by regulating the number of working pumps. The paper introduces new pressure control algorithms based on the working point estimation intended for programmable logical controllers (PLC). Experiments prove correctness of the offered methodology.

Predictive control of a variable-speed multi-pump motor drive

This paper addresses performance improvement of the centrifugal pumps running in variable-speed applications. Focus is on the system operation in the best-efficiency region. The impact of various factors affecting the pumping efficiency in the single-pump and multi-pump environments is described. A method for the multi-pump drive predictive control is proposed.

Hardware-in-the-loop simulation of motor drives for pumping applications

A method of taking characteristics of the pump motor drive using a hardware-in-the-loop simulation approach is described. The models with built-in hardware and software components of real equipment were developed. To study the drives of centrifugal pumps manufactured by ABB, their own control system was used whereas the pumping load has been replaced with the specially designed environment simulators which description was initially unclear. To clarify the model topology and parameters, a double-motor assembly was constructed and applied as universal pump prototype. Real equipment included into the simulation loop allows to decrease a priori uncertainty and to explore the processes that have nether evident characterization. A library of reference and disturbance signals typical for pumping was prepared and used as the models. Hence, the advantages of mathematical and physical simulations were combined with optimal interaction of both approaches.

Efficiency control for adjustment of number of working pumps in multi-pump system

Adjustment of working state of the pump in order to satisfy the changing demand and hence bringing the system outside of best efficiency region is a reason of occurrence of dimensioning and adjustment losses. This phenomena is more harmful in multi pump applications e.g. parallel pumping. Method to monitor and predict the location of working point using quite common processing equipment is proposed. Adjusting the working state on basis of prediction of working point location was implemented and tested in the laboratory.

Multi-motor pressure management system with minimal energy consumption

The paper focuses on the smart fluid adjustment of the centrifugal pumping station. The goal of the study is to provide the pressure management at minimal consumed energy. To solve the problem, the sensorless prediction method is proposed. The multi-motor variable speed drive has been designed and analyzed. A research is supported by experiments on the ABB Ebara CDX 120/12 pumping station fed by five ACQ810 variable speed induction motor drives with direct torque control. The offered multi-motor model is implemented based on ABB programmable logical controller AC500 PM 571 connected to the drives via the Profibus.

Hardware-in-the-loop simulator of a flow control system for centrifugal pumps

A hardware-in-the-loop model of a centrifugal pump is proposed. The new simulator consists of the pump and pipeline imitators built on the basis of the variable speed drives connected via the programmable logical controller and Profibus communication components. The mathematical description of the flow maintenance represents a core of the simulation methodology. To study the system, a series of tests have been conducted that proved the designed system flexibility and accuracy in flow control imitation at the steady-state pumping mode.

Simulation study of the pressure control system for a centrifugal pump

In this paper, the simulation environment is proposed that enables accurate full-scale investigation of the pressure adjustment for a centrifugal pump. The novel Matlab model is described, the pumping control procedure is explained, and the simulation results are assessed with the help of an experimental pumping test bench. Basing on thorough inspection of the developed software, the offered toolbox can be considered as a sensible tool for finding optimal pressure adjustment potential at high-quality pumping.

Study of the centrifugal pump efficiency at throttling and speed control

Centrifugal pumping systems are the common hydraulic devices mainly driven by electric drives. Their efficiency varies significantly with the change of working point location that depends on the positions of the performance and system curves. This paper is devoted to the study of the pumping system efficiency at throttling and speed control. A model-based calculation method for the single-drive centrifugal pump head and pressure control is described. The proposed Matlab model was tested with the help of a real test bench. The results obtained confirm the model validity and accuracy.

Speed control strategy selection for multi-pump systems

Parallel multi-pump single-drive pumping systems are widely used in water processing applications. Comparison of this type of systems to multi-pump multi-drive solutions is discussed. The drawbacks and advantages of both systems are identified. Recommendations on pumping system energy efficiency monitoring techniques which include sensorless estimation are proposed. Problem of trade-off between the energy efficiency and efficiency of pump is proposed for future research.

Simulation study of mixed pressure and flow control systems for optimal operation of centrifugal pumping plants

Abstract A Simulink/DriveSize based model for the mutual pressure and flow control of a centrifugal pumping plant with a variable speed drive is proposed. The model provides the possibility of power calculation during both throttling and speed control and to estimate the optimal working point according to these calculations. The model is developed to provide the possibility of power reduction during pressure and flow maintenance with the help of mixed pressure control strategy. To evaluate the system, a series of experiments have been conducted. After the validation of the proposed model through testing, which proved that the designed system is more beneficial from the power consumption point of view than the traditional pressure control methods, it can be stated that the system is useful for pressure and flow control optimization of the centrifugal pumping plants