Magnetic Flowmeter Independent Coil Drivers PID Control
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Solution Overview
Problem
Magnetic flowmeters face accuracy issues due to temperature variations affecting coil resistance and symmetry deviations in the magnetic field, leading to altered measurement accuracy.
Innovation Solution
A system with independent coil drivers and voltage regulators, utilizing sensors and a PID controller to maintain a prescribed magnetic field by adjusting current through coil assemblies, accounting for non-symmetrical conditions and temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single coil driver is used to simplify the device structure, then device complexity is reduced, but temperature variations and symmetry deviations affect coil resistance uniformly, leading to altered magnetic field and reduced measurement precision
Solution Approach 1:
The single coil driver is segmented into two independent coil drivers, each controlling one coil assembly. This allows independent adjustment of current through each coil to compensate for temperature variations and symmetry deviations, thereby maintaining measurement precision while managing device complexity through modular independent control units.
Solution Approach 2:
A feedback control system is implemented where sensors detect the actual magnetic field conditions and coil resistance, and this information is fed back to the independent coil drivers. The drivers adjust the current through each coil based on the feedback to maintain a prescribed magnetic field, resolving the contradiction between simple structure and precise measurement.
2Measurement precision
If independent coil drivers with feedback control are used to maintain prescribed magnetic field, then measurement precision is improved, but device complexity increases due to additional sensors and control systems
Solution Approach 1:
The control system is segmented into two independent control loops, each managing one coil assembly with its own sensor and driver. This modular approach achieves precise magnetic field control while organizing the complexity into manageable, repeatable units that can be independently optimized and maintained.
Solution Approach 2:
The system dynamically changes the electrical parameters (current, voltage) of each coil based on real-time feedback from sensors. By adjusting these parameters independently for each coil, the system compensates for temperature variations and symmetry deviations, achieving high measurement precision despite the increased control system complexity.
3Ease of operation
If constant current is provided to coil assemblies, then device operation is simplified, but temperature variations alter coil resistance and magnetic field strength, reducing measurement precision
Solution Approach 1:
The system replaces simple constant current operation with a feedback-controlled variable current system. Sensors monitor the actual current and magnetic field conditions, and this feedback is used to dynamically adjust the current through each coil to maintain a prescribed magnetic field, thereby preserving measurement precision while maintaining ease of operation through automatic control.
Solution Approach 2:
The coil driver operation transitions from static constant current to dynamic current adjustment based on real-time conditions. The independent coil drivers continuously adapt the current magnitude to compensate for temperature variations and resistance changes, maintaining magnetic field consistency without requiring manual intervention, thus balancing ease of operation with measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures accurate fluid flow measurements by maintaining a consistent magnetic field, minimizing errors caused by temperature variations and coil symmetry deviations, thereby enhancing the precision of magnetic flowmeter readings.
Implementation Method 1
A first coil driver passes a first current through a first coil assembly and a second coil driver passes a second current through a second coil assembly to create a magnetic field within a fluid flow path
Implementation Method 2
Magnetic flow meters measure the velocity of conductive fluids passing through pipes by generating a magnetic field and measuring the resultant voltage. These flowmeters rely upon Faraday's Law in which the flow of a conductive fluid through a magnetic field causes a voltage signal
Data Source
AI summary
A magnetic flow meter assembly having a tubular body that has two opposing ends that define a fluid flow path therebetween for a conductive fluid. The magnetic flow meter assembly further includes a pair of coil assemblies which are configured to pass current as received from voltage regulators via a first and second coil driver. The coil assemblies can therefore generate a magnetic field wherein a pair of measuring electrodes detect a voltage induced by the conductive fluid passing through said magnetic field. Moreover, the coil assemblies are each electrically coupled with at least one sensor that provides feedback to a respective voltage regulator via a proportional-integral-derivative (PID) controller configured to minimize the error between a respective measured current and a target current. The respective voltage regulators can use the received feedback to manipulate the current passing through the corresponding coil assembly to enabling a prescribed magnetic field to be created within the fluid flow for accurate flow measurement.