Self-sensing parallel control of pumps

Abstract

A hydraulic pumping system for pumping a flow of aqueous liquid, for HVAC and potable water systems, through a plurality of hydraulic pump assemblies and mating branching feeder pipes extending between a main inlet pipe and a main outlet pipe for outputting the total flow of water, each of said pump assemblies in operative association with a mating feeder pipe to control aqueous liquid flow through said associated feeder pipe, wherein each of the hydraulic pump assemblies comprises an electric motor, mechanically coupled to a centrifugal pump and a variable frequency drive (VFD) electrically coupled to the motor. A controller is electrically coupled via a communication channel to the VFD of each of the hydraulic pump assemblies, the controller comprising a programmable device programmed to control the speed of each of the motors via the connected VFD. The controller receives data from each of the VFDs, said data comprising the amount of electrical power consumed by the VFD, the speed of the associated motor, an estimation of aqueous liquid flow, and an estimation of head, and calculates the total aqueous liquid flow through the plurality of pump assemblies, and the total system head, so that the controller can vary the speed of each VFD to adjust the total system with respect to the desired system head.