The control of variable speed pumps in series operation

This paper presents a simulation model for the operation of two series pumps, the second being driven with variable speed. Although this is not usual for this type of configuration that requires generally both pumps working at the same speed, it seems to be preferred in practice. The model was developed so that to be able to quickly check the efficiency variable speed drives based on real values, each time more. This can make possible the choice of other equipments leading to the highest efficiency. The mathematical model was developed in per units in MATLAB/Simulink environment and can be used for all types of pumps. Key-words: pump, variable speed drive, series operation, mathematical model, simulation.