Magnetic Flowmeter Boost Supply for Coil Surge Stabilization
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Solution Overview
Problem
Conventional magnetic flowmeters face challenges in managing large inductive switching loads, leading to extreme current surges that can overwhelm power supplies and affect the accuracy of flow rate measurements due to the dynamic nature of the magnetic field generation.
Innovation Solution
The integration of a load leveling boost supply circuit and power scavenging circuitry that regulates the current to a constant value, capturing and reusing the counter EMF energy stored in the inductive load during current reversal cycles to stabilize the power supply and reduce dynamic current surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power supply is used to drive the coil, then the magnetic flowmeter can generate the magnetic field, but large current surges occur during inductive switching that destabilize the power supply and affect measurement accuracy
Solution Approach 1:
The boost converter is activated before the coil driver switches the coil current, pre-charging the output capacitor to the required voltage level. This preliminary action ensures that when the coil switches occur, the power supply is already prepared and can handle the transient demands without destabilizing, thus preventing current surges that would affect measurement accuracy
Solution Approach 2:
The boost converter acts as an intermediary power conditioning device between the input power source and the coil driver. It isolates the sensitive measurement circuitry from the high-current switching transients by providing a buffered, regulated output that can absorb the inductive kicks without propagating them back to affect the EMF measurement accuracy
2Measurement precision
If the coil current is switched to reverse direction for accurate flow measurement, then the magnetic field direction changes to detect bidirectional flow, but large inductive current kicks are generated that surge the power supply
Solution Approach 1:
The energy from the inductive current kick generated during coil reversal is not discarded but captured and stored in the boost converter's output capacitor. This previously harmful transient is converted into a useful energy reservoir that can supply power during subsequent switching cycles, reducing the overall stress on the power supply while maintaining the necessary current reversal for bidirectional flow measurement
Solution Approach 2:
Instead of dissipating the inductive energy as heat or noise during coil current reversal, the system recovers this energy through the boost converter's rectification and storage mechanism. The recovered energy is stored in the output capacitor and reused to power the coil during the next activation cycle, thereby stabilizing the power supply current while enabling accurate bidirectional flow measurement through current reversal
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 effectively stabilizes the power supply, reducing large current surges and maintaining accurate flow rate measurements by ensuring a constant current supply, thereby enhancing the reliability and precision of magnetic flowmeters.
Implementation Method 1
magnetic flowmeters rely upon the conductivity of the process fluid, and the electromotive force (EMF) induced as the fluid flows through a region of magnetic field
Implementation Method 2
Magnetic flowmeters are distinguished from these technologies by characterizing a flow based on Faraday's Law, which depends upon electromagnetic interactions
Implementation Method 3
capturing and reusing the counter EMF energy stored in the inductive load during current reversal cycles
Implementation Method 4
A load leveling boost supply provides power to the current supply circuitry. Additionally, power scavenging circuitry recovers power from the coil
Data Source
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AI summary
A magnetic flowmeter (100) for measuring a fluid flow includes a flow tube assembly (102) receiving the flow and having a coil (104) with first and second coil wires for receiving a coil current and responsively producing a magnetic field thereby generating an EMF in the fluid representative of a flow rate. An EMF sensor (107) is arranged to sense the EMF and generate an output indicating the flow rate. Current supply circuitry (128) applies a current supply signal to the coil (104). A load leveling boost supply (120) provides power to the current supply circuitry (128). In another aspect, power scavenging circuitry (C2) recovers power from the coil (104).