Ilja Bakman

Sensorless pressure control of centrifugal pumps

A converter-fed system is proposed which successfully estimates and regulates the operational state of the pumping process without excess sensors. Sensorless control provides such advantages as cost savings resulting from exclusion the need in sensor incorporation in the drive and the driven system; increased reliability due to the absence of additional components, such as sensors, cables, connections that can cause malfunction; and fewer maintenance and data exchange operations. Such benefits are based on adjustable models that can be currently modified and corrected along with the test measurements in the system with known characteristics. Adjustable models describing the driven process could be added to the control scheme of the variable speed drive to exclude additional measurements for control.

Control of Electric Drives in the Best Efficiency Region of Pumping System

Abstract The paper concentrates on improving the efficiency of the pumping system in which pumps are run by variable speed drives. The method is applicable to system consisting of several centrifugal pumps. Problems arising from running the pumps outside the optimal efficiency region are discussed. Common principles of operation and control of typical boosting pumping station are represented. Methods of regulation of productivity of the system are described. The proposed method is based on prediction of future efficiency of pumps before making adjustments of pumping system productivity. The proposed method is basing on tracking the working point of pump on efficiency graph. Monitoring the location of working point vs. efficiency graph enables to evaluate its current and future distances from the best efficiency point of the pump. Knowing the current number of running pumps it is possible to predict the location of working point after adjustment of productivity of the system. Ability to predict the increase or decrease of efficiency enables to enhance the adjustment of productivity of the system. Methods of graphical analysis of working state of the pumping system are representing topic for future research.

Performance Improvement of Pumps Fed by the Variable Speed Drives

Abstract Speed inaccuracy decreases the pump efficiency, reliability, and energy saving. This research is devoted to the determination of the ways of accurate speed control of the pump drives operated under changeable loads. The impact of speed inaccuracy on the pump performance is studied. Based on the analysis of methods for the static accuracy improvement, the drawbacks of the traditional approaches have been shown with reference to the pumping applications. A new methodology of the slip compensation has been proposed for implementation to improve the scalar drive performance. It notably decreases the speed inaccuracy of the open-ended pumping applications. The enhanced quality of the drive control at different loading conditions has been shown on a laboratory test bench. Also, for the multi-pump systems this approach results in an additional benefit from the viewpoint of the operation around the best operation point providing a safe pump control both to exclude the pump damage and to improve the process quality.

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.

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.

High-efficiency predictive control of pumping

A novel method is offered to control centrifugal pumping stations with variable speed drives and programmable logical controllers. Using pre-defined tabularized data, efficiency estimates are applied for different number of pumps operated at various speeds. The control strategy is proposed basing on both the analytical performance characteristics and the experimental efficiency distribution diagrams of pumps. An efficiency map has been designed in which the optimal number of pumps is recorded targeting to maintain the system performance in the best efficiency regions. Experimental results validate the new control approach.

Energy-efficient predictive control of centrifugal multi-pump stations

A novel head and pressure predictive control approach is offered for the centrifugal multi-pump stations equipped with variable speed drives and programmable logical controllers. The pre-defined tabularized data are used where the efficiency estimates for different number of pumps operated at various speeds are collected. Thanks to accounting the motor drive power losses, maximal system efficiency is obtained as the main outcome without equipment oversizing. The total head and pressure management strategy is proposed basing on both the analytical performance characteristics and the experimental efficiency distribution diagrams of a multi-pump station. Using this efficiency distribution, the efficiency map is proposed where the optimal numbers of pumps are recorded aiming to maintain the system performance in one of the best efficiency regions. An appropriate control algorithm is described. Finally, some experimental results validated the new control methodology are discussed.

Hardware-in-the-loop simulator of vessel electric propulsion drive

A hardware-in-the-loop (HIL) model of a vessel electric propulsion drive is proposed. The mathematical description of the vessel trust forces is explained. As well, the propulsion power and torque estimates are discussed within the broad spectre of their parameter changing. A case study is reported where some concrete parameters are applied in the above mathematical model to assess the particular project with the help of HIL approach. Results of simulation and experimentation prove the correctness of the design and research methodology.