Sensorless Multi-Pump Control via Quadratic Head Loss Estimation
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Solution Overview
Problem
Multipump systems without sensors face discontinuities in flow rate due to variable pump activation and imbalances, even with identical pumps, leading to inefficiencies in controlling pressure differences across the system.
Innovation Solution
A method and system that estimate pressure differences across each pumping cell, accounting for head losses using a quadratic correction value, allowing for centralized control of a multipump system by determining a reference speed based on these estimates, eliminating the need for individual pump control strategies and sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sensorless control is used to reduce cost and maintenance, then device complexity and maintenance costs are reduced, but measurement precision and control accuracy deteriorate due to discontinuities in flow rate
Solution Approach 1:
The patent introduces a quadratic correction value as an intermediary parameter to compensate for head losses in the piping system. This correction value acts as a mediator between the pump's head-output characteristics and the actual system performance, allowing the control system to achieve accurate flow rate control without direct sensors by mathematically compensating for system losses.
Solution Approach 2:
The patent changes the control parameter from direct head control to head control with quadratic correction. By modifying the control parameter to include a quadratic correction term that accounts for head losses, the system achieves more accurate flow rate control while maintaining the sensorless architecture.
2Productivity
If individual pump control strategies are used, then each pump can be optimized independently, but device complexity and control difficulty increase
Solution Approach 1:
The patent merges the control of multiple parallel pumps into a unified control approach. Instead of implementing separate control strategies for each pump, the system applies a single quadratic correction value to the overall system, simplifying the control architecture while maintaining optimization of individual pump operations through the common control framework.
3Use of energy by moving object
If pumps are activated variablely to match demand, then energy efficiency improves, but flow rate stability deteriorates due to discontinuities
Solution Approach 1:
The patent implements a feedback mechanism where the quadratic correction value is determined based on system operating conditions and fed back into the control loop. This feedback allows the system to adjust pump operation dynamically, maintaining flow rate stability even when pumps are activated or deactivated to match energy-efficient operating points.
Data Source
AI summary
A method and a system for controlling a multipump system used to pump a fluid. The system includes n pumping cells (Ci) connected in parallel, with n greater than or equal to 2. The system is controlled by using a reference pressure difference. The method includes estimating a pressure difference (dPpumpi) generated by each pumping cell (Ci) taking into account of a quadratic correction value (HEGi) representing the head losses of the pumping cell, estimating a pressure difference (dPSys) of the multipump system from the pressure difference estimated for each pumping cell, comparing the multipump estimated pressure difference (dPSys) with the reference pressure difference (dPsp) in order to control the reference speed (Wref) to be injected into a control loop of the multipump system.