Sensorless Pump Converter Using Affinity Equations
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Solution Overview
Problem
Existing techniques for controlling multiple pump configurations in hydronic systems lack effective sensorless conversion methods for accurately determining total pressure and flow rate, especially in configurations where pumps are arranged in series or parallel, leading to inefficiencies and inaccuracies in monitoring and control.
Innovation Solution
A direct numeric affinity multistage pumps sensorless converter is developed, utilizing a signal processor that applies combined affinity equations and numerical interpolation algorithms to derive instant pump differential pressure and flow rate from motor speed and power data, enabling accurate control and monitoring of multiple pump configurations without the need for sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sensorless conversion techniques are used for multiple pump configurations, then the need for physical sensors is eliminated and system complexity is reduced, but measurement precision and conversion accuracy deteriorate
Solution Approach 1:
The patent applies parameter changes by utilizing pump affinity laws that relate pump performance parameters (flow rate, head, power) to rotational speed. By changing the speed parameter and applying affinity equations, the system can derive instantaneous pump differential pressure and flow rate from motor readout values without physical sensors, thus reducing system complexity while maintaining conversion accuracy through mathematical relationships.
Solution Approach 2:
The patent replaces the mechanical sensor-based measurement system with a computational approach using affinity equations and numerical interpolation algorithms. Instead of using physical sensors to directly measure pump differential pressure and flow rate, the system substitutes these mechanical measurements with mathematical calculations based on motor speed and power readouts, thereby eliminating the need for additional sensors while achieving satisfactory conversion accuracy.
2Ease of operation
If existing sensorless conversion techniques are applied to multiple pump configurations, then implementation is simplified, but measurement precision deteriorates due to lack of configuration-specific methods
Solution Approach 1:
The patent applies segmentation by dividing the multiple pump system into individual pump units, each with its own affinity characteristics. The system processes each pump's motor readout values separately using configuration-specific affinity equations, then combines the results to determine total system differential pressure and flow rate. This segmented approach maintains implementation simplicity while improving measurement precision by accounting for the specific hydraulic characteristics of each pump configuration.
Solution Approach 2:
The patent applies dynamics by developing adaptive conversion methods that adjust the affinity equations and numerical interpolation algorithms based on the specific multiple pump configuration (series, parallel, or combination). The system dynamically selects and applies the appropriate mathematical model for the given configuration, enabling accurate real-time conversion of pump differential pressure and flow rate while maintaining ease of operation through automated configuration detection and adaptation.
Data Source
AI summary
Apparatus, including a pump system controller, features a signal processor or processing module configured at least to: receive signaling containing information about pump differential pressure, flow rate and corresponding power data at motor maximum speed published by pump manufacturers, as well as instant motor power and speed, for a system of pumps arranged in a multiple pump configuration; and determine corresponding signaling containing information about instant pump differential pressure and flow rate for the system of pumps arranged in the multiple pump configuration using a combined affinity equation and numerical interpolation algorithm, based upon the signaling received.