Method And System For Fluid Flow Control In A Fluid Network System

A method of controlling fluid flow in a fluid network system by means of a plurality of fluid machines, wherein the method comprises:

• a) obtaining a respective current fluid flow rate associated with each fluid machine,
• b) obtaining a current fluid machine speed of each fluid machine,
• c) obtaining desired fluid flow rates in the fluid network system,
• d) determining a new fluid machine speed for each fluid machine based on the current fluid machine speeds and a change in the fluid machine speed required to obtain the desired fluid flow rates, wherein the change in the fluid machine speed is determined by minimizing a total fluid machine power which is a function dependent of the change in the fluid machine speed, the minimization being performed with constraints for fluid flow rate, fluid machine pressure and fluid machine speed,
• e) controlling the speed of the plurality of fluid machines according to the new fluid machine speeds such that the minimum total fluid machine power in the fluid network system is attained, and prior to obtaining a respective current fluid flow rate, determining a mod& of the total fluid machine power by determining a relation between a change in fluid machine speed and a corresponding change in fluid machine power for each of the plurality of fluid machines empirically, wherein the relation forms part of the model and wherein the model is utilized for the minimization.