Sensorless Hydronic Pump Control With Self-Calibration
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Solution Overview
Problem
Existing hydronic pumping systems face challenges in energy efficiency and maintenance costs due to the need for flow meters and pressure sensors, which can be absent or unreliable in dynamic systems.
Innovation Solution
A sensorless adaptive pumping control technique that integrates adaptive pump control with a self-calibration scheme, allowing for automatic recalibration without flow meters or pressure sensors, using motor operation variables to estimate system pressure and flow rates and adjust the adaptive pressure set point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow meters and pressure sensors are used to obtain system characteristics for adaptive pump control, then measurement precision is improved, but device complexity and maintenance costs increase
Solution Approach 1:
The patent extracts the measurement function from external sensors (flow meters and pressure sensors) and relocates it to the motor controller by utilizing existing motor operation variables. This eliminates the need for separate sensing equipment while maintaining the capability to obtain system characteristics for adaptive control.
Solution Approach 2:
The patent introduces motor operation variables (current, voltage, speed) as an intermediary to indirectly obtain system pressure and flow rate information. Instead of directly measuring hydraulic parameters, the system uses electrical-mechanical coupling relationships to derive the required system characteristics through the motor's operational data.
2Reliability
If traditional pressure sensors and flow meters are installed in the system, then reliability of system monitoring is improved, but ease of operation and maintenance are worsened due to additional failure points and calibration requirements
Solution Approach 1:
The system performs self-measurement and self-monitoring by utilizing its own motor operation variables. The motor controller inherently possesses the data needed to determine system characteristics, eliminating the need for external monitoring equipment that would require separate maintenance and calibration activities.
Solution Approach 2:
The motor controller is given a multi-functional role, serving both as the drive for the pump and as the measurement and control system. This universal approach allows a single device to perform multiple functions, reducing the overall system complexity and maintenance burden while maintaining monitoring reliability.
3Device complexity
If sensorless adaptive control is implemented without flow meters or pressure sensors, then device complexity is reduced, but measurement precision of system characteristics may deteriorate
Solution Approach 1:
The patent replaces mechanical/hydraulic measurement systems (flow meters and pressure sensors) with an electrical measurement approach using motor operation variables. By utilizing the well-defined electrical-mechanical relationships in motor drives, the system achieves accurate determination of system characteristics through electrical parameters rather than direct hydraulic measurement.
Solution Approach 2:
The system implements a feedback mechanism where motor operation variables are continuously monitored and used to update the system characteristics determination. This closed-loop approach allows the controller to adaptively refine its understanding of system pressure and flow rate based on actual motor performance data, maintaining measurement precision without external sensors.
Data Source
Figure 1~1B
Figure 2
Figure 3~4
AI summary
The present invention provides apparatus that features a signal processor or processing module configured to receive signaling containing information about an adaptive or self-calibrating set point control curve and a varying equivalent system characteristic curve based at least partly on an instant pump pressure and a flow rate using an adaptive moving average filter, and equivalent hydronic system characteristics associated with the instant pump pressure and the flow rate to corresponding motor power and speed reconstructed and remapped using a discrete numerical approach; and determine an adaptive pressure set point, based at least partly on the signaling received.