Investigation of an Energy Efficient Pump Speed Control Algorithm For Controlling Sump Level

This paper explores a new nonlinear control algorithm for variable speed centrifugal pumps at water/wastewater pump stations that leads to specific energy savings over the conventional linear one. The algorithm is useful for facilities where pump speed is a linear function of liquid level in order to transport fluid and smooth inflow peaks. A nonlinearity in the form of a quadratic term is added to the conventional linear one in order to produce efficiency gains, with a single parameter, curvature, varied to optimize energy savings. Results obtained by implementing the new algorithm on a pilot-scale pump station show significant energy savings for fixed pump flow, with a parabolic correlation of specific energy savings versus curvature of the nonlinear quadratic determined. In addition, the cost of implementing this algorithm is minimal to none, so the work presented has major industrial potential.