Positive Displacement Pump Controller with Dynamic Limit Values
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Solution Overview
Problem
Positive displacement pumps face risks of self-destruction or damage due to unsuitable frequency converter regulators, which are not optimized for these pumps, and also affect the quality of the delivery fluid, as existing regulators do not account for dynamic operating parameters.
Innovation Solution
A controller for positive displacement pumps that generates a manipulated variable for the frequency converter based on a reference input variable and actual operating parameters, using dynamic limit values calculated from sensors or simulations, to prevent damage and ensure fluid quality by comparing the variable with protection and quality limit values, and adjusting the output accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a regulator designed only for specific motors is used in frequency converters, then the motor control function is achieved, but the positive displacement pump is at risk of damage due to lack of pump-specific optimization
Solution Approach 1:
The regulator dynamically adjusts operating parameters based on real-time pump condition monitoring. It continuously evaluates actual operating parameters against dynamically determined limit values and adapts the manipulated variable accordingly, transitioning from static motor-specific control to dynamic pump-optimized control that responds to changing operational conditions
Solution Approach 2:
The regulator implements a feedback mechanism by continuously monitoring actual operating parameters of the positive displacement pump and comparing them against dynamically determined limit values. When deviations are detected, the regulator automatically adjusts the manipulated variable to correct the deviation, creating a closed-loop control system that ensures pump safety while maintaining operational flexibility
2Reliability
If dynamic limit values are calculated and compared with manipulated variables to protect the pump, then pump damage is prevented, but the controller complexity increases
Solution Approach 1:
The regulator performs self-service by automatically calculating dynamically determined limit values based on pump-specific parameters and operating conditions. The system autonomously monitors its own operation, compares actual parameters against calculated limits, and adjusts control variables without external intervention, thereby providing pump protection through self-monitoring and self-correction capabilities
Solution Approach 2:
The regulator changes control parameters dynamically by calculating limit values that adapt to varying operating conditions. Instead of using fixed thresholds, the system continuously updates parameter limits based on actual pump performance data, fluid properties, and operating context, allowing complex protection logic to be implemented through parameter adaptation rather than structural complexity
3Speed
If the manipulated variable is directly sent to the frequency converter without correction, then the control response is fast, but the pump may be damaged or fluid quality may deteriorate
Solution Approach 1:
The regulator performs preliminary action by pre-calculating dynamically determined limit values and safety thresholds before manipulating the frequency converter. The system proactively establishes safe operating boundaries and pre-evaluates control commands against these boundaries, preventing harmful actions before they occur while maintaining rapid response capability through pre-prepared safety parameters
4Reliability
If pump-specific optimization is implemented in the regulator, then pump safety is improved, but the regulator cannot be used with other pump types
Solution Approach 1:
The regulator achieves pump-specific optimization through parameter configuration rather than structural specialization. By accepting pump-specific parameters as input and calculating dynamically determined limit values based on these parameters, the same regulator hardware and software architecture can be adapted to different positive displacement pump types through parameter changes, maintaining universality while providing specialized protection
Data Source
AI summary
A controller for controlling a frequency inverter of a positive displacement pump motor of a positive displacement pump. The controller comprises a control unit configured to produce a control variable (Ys) for a frequency inverter of a positive displacement pump motor depending on a reference variable (W) and a first actual operating parameter (X). According to the invention, the control unit is associated with logical means having a first threshold value defining means that are designed to determine at least one first threshold value (YGrenzmax, YGrenzmin) depending on the first actual operating parameter (X) and/or at least one further actual operating parameter (XH, YH, YHH) that could lead to a failure state of the positive displacement pump when exceeded or fallen short of.