Series Voltage Regulator for Stable Loop Current

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Solution Overview

Problem

Existing loop-powered field devices for process variables, such as radar level gauges, face inefficiencies in energy utilization and stability of regulated loop current, particularly due to variations in loop voltage.

Innovation Solution

A field device with a measurement device, a current control device, and voltage regulation circuitry connected in series, where the voltage regulator controls the voltage across the current control device to maintain a desired voltage, reducing voltage variation and enhancing stability, while also blocking external disturbances by varying the voltage drop quickly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the measurement device, current control circuit, and shunt regulator are connected in parallel, then the device structure is simple, but a relatively large portion of the available electrical power is not used for powering the measurement device

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcircuit configuration complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The circuit is segmented into distinct functional blocks: voltage regulation circuitry (22), current control device (23), and measurement device (24). This segmentation allows each component to perform its specific function optimally while working together in a series configuration to achieve both energy efficiency and functional performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The voltage regulation circuitry dynamically adjusts the voltage across the current control device to maintain optimal operating conditions. This dynamic control enables the system to efficiently utilize available electrical power while maintaining stable operation of the measurement device despite variations in loop voltage.

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If a voltage regulator is added to improve energy efficiency, then power utilization improves, but the stability of the regulated loop current deteriorates due to voltage variations

Engineering Contradiction:
Improvepower utilizationVSAvoidloop current stability
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The voltage regulator implements feedback control by continuously monitoring the voltage across the current control device and adjusting its output to maintain a stable voltage. This feedback mechanism ensures that the measurement device receives consistent power while maximizing the utilization of available electrical power from the loop.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the voltage parameter dynamically through the voltage regulator to optimize power utilization. By adjusting the voltage across the current control device within acceptable ranges, the system maintains both high power utilization and stable loop current operation despite external voltage variations.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If the voltage regulator varies the voltage quickly to block disturbances, then interference protection improves, but the complexity of the voltage regulation circuitry increases

Engineering Contradiction:
Improveinterference blockingVSAvoidvoltage regulation circuitry complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The voltage regulator employs periodic switching action to quickly respond to and block external disturbances. By using pulsed or cyclic control mechanisms, the circuit can rapidly adjust the voltage to counteract interference while maintaining a relatively simple overall circuit architecture through the use of standard switching components.

Inventive Principle:
Principle #19Periodic action

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 configuration allows for stable and efficient use of available power, improving the stability of the regulated loop current and preventing interference, thus enhancing the operational reliability and energy efficiency of the field device.

Implementation Method 1

voltage regulation circuitry electrically connected in series with the current control device and the measurement device for controlling a voltage across the current control device towards a desired voltage by varying a voltage across the voltage regulation circuitry

Methodology Applied
Scientific EffectElectrical impedance modulation: Electrical Resistance

Data Source

PatentEP3298470B1Loop-powered field device with voltage regulator and current source in series
Publication Date: 2021.01.20 ROSEMOUNT TANK RADAR
  • EP3298470B1 patent drawingFigure 1
  • EP3298470B1 patent drawingFigure 2
  • EP3298470B1 patent drawingFigure 3

AI summary

The present invention relates to a field device for determining a process variable and providing a measurement signal indicative of the process variable to a remote location via a two-wire current loop. The field device comprises a measurement device for determining the process variable; a current control device electrically connected in series with the measurement device and controllable by the measurement device to provide the measurement signal to the two-wire current loop; and voltage regulation circuitry electrically connected in series with the current control device and the measurement device for controlling a voltage across the current control device towards a desired voltage by varying a voltage across the voltage regulation circuitry.