Sensorless Pump Processing Using Direct Numeric Affinity Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sensorless control methods for hydronic pumping systems face challenges in accurately determining pump differential pressure and flow rate without reconstructing and solving pump and system characteristics equations, especially for more complex characteristic distributions.
Innovation Solution
A direct numeric affinity pump sensorless converter is developed, using pump differential pressure, flow rate, and power at maximum speed, along with the pump affinity law, to compute instant pump differential pressure and flow rate directly and numerically, eliminating the need to invert system characteristics coefficients or perform calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pump and system characteristics equations are reconstructed and solved to determine differential pressure and flow rate, then measurement precision may be improved, but device complexity and calibration requirements increase
Solution Approach 1:
The patent extracts only the necessary parameters (differential pressure and flow rate) directly from motor readout values using affinity laws, eliminating the need to reconstruct and solve complex pump and system characteristics equations. This extraction approach maintains measurement precision while significantly reducing computational complexity and calibration requirements.
Solution Approach 2:
Instead of solving forward from pump characteristics to determine operating points, the patent inverts the approach by using affinity laws to directly calculate differential pressure and flow rate from motor readout values. This inversion simplifies the computational path while maintaining accuracy.
2Measurement precision
If calibration data acquisition is performed to improve conversion accuracy, then measurement precision improves, but loss of time and ease of operation deteriorate
Solution Approach 1:
The system performs self-service by using the pump's own motor readout values and published affinity laws to determine differential pressure and flow rate without requiring external calibration data acquisition. This eliminates calibration time while maintaining conversion accuracy through the inherent accuracy of affinity laws.
3Measurement precision
If system characteristics coefficients are inverted to solve pump equations, then measurement precision may improve, but device complexity and computation time increase
Solution Approach 1:
The patent extracts the required pump parameters (differential pressure and flow rate) directly from motor readout values using affinity laws, bypassing the need to invert system characteristics coefficients or solve complex pump equations. This extraction method maintains precision while eliminating computational complexity.
Solution Approach 2:
The patent inverts the traditional approach by not solving for system characteristics coefficients at all. Instead, it directly calculates the desired parameters from motor readings using affinity relationships, reversing the computational direction to achieve simplicity.
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3~4
AI summary
The present invention provides a numerical affinity pump sensorless conversion signal processing technique, e.g. based upon processing the pump differential pressure, flow rate and power at pump maximum speed published by pump manufacturers, as well as the pump affinity law in order to obtain instant pump differential pressures and flow rate directly and numerically. The sensorless converter technique may be applied to any form of pump characteristics distributions simple or complicated, since there is no need to reconstruct and to solve any pump and system characteristics equations. As a result, the computation accuracy is significantly improved.