Two-Wire Field Device Power Scavenging via Series Current Regulator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In industrial process field devices powered by two-wire control loops, the limited power availability restricts the functionality of circuitry due to reserved current for shunt regulators, particularly in HART communication protocols, leading to inefficient power scavenging and reduced power allocation to device functions.
Innovation Solution
The implementation of a series current regulator and parallel voltage regulator, along with a bulk capacitor, allows for efficient power scavenging by modulating the HART communication protocol current through the series regulator path, reducing bias current requirements and optimizing power allocation to device circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power is received from a two-wire industrial process control loop, then the field device can be powered and communicate, but the power available to the process field device is limited
Solution Approach 1:
The patent combines the power scavenging function with the existing series and shunt regulators in the two-wire control loop. By integrating power extraction circuitry that operates in parallel with the shunt regulator and in series with the series regulator, the system merges multiple functions (power regulation, power scavenging, HART communication) into a unified power management architecture, thereby increasing power availability without proportionally increasing device complexity
Solution Approach 2:
The control loop serves multiple functions simultaneously: it provides power to the field device, enables HART communication, and allows power scavenging for additional circuitry. The patent implements a universal power management system where the same two-wire loop supports both traditional loop-powered operation and enhanced power scavenging modes, maximizing the utility of the existing control infrastructure
2Use of energy by moving object
If current is reserved for shunt regulators in HART communication systems, then HART communication can be maintained, but power allocation to device functions is reduced
Solution Approach 1:
The patent segments the power management functions into distinct components: a series regulator for current control, a shunt regulator for voltage regulation, and a separate power scavenging circuit. This segmentation allows independent optimization of each function, enabling the power scavenging circuit to extract additional power without compromising the HART communication functions handled by the shunt regulator
Solution Approach 2:
The patent introduces a power scavenging circuit as an intermediary component that operates between the series and shunt regulators. This intermediary extracts additional power from the control loop through parallel connection with the shunt regulator and series connection with the series regulator, providing supplemental power to device functions while maintaining the integrity of HART communication signals
Data Source
AI summary
A process field device for use in monitoring or controlling an industrial process includes first and second loop terminals configured to couple to a two-wire industrial process control loop. Field device circuitry is configured to monitor or control a process variable of the industrial process. The field device circuitry is powered by power connections from the two-wire industrial process control loop. A current regulator is connected in series with the two-wire industrial process control loop, the first and second loop terminals and the field device circuitry. The current regulator is configured to control a loop current flowing through the two-wire process control loop. A voltage regulator is connected in parallel with the current regulator and in series with the two-wire industrial process control loop, first and second loop terminals and field device circuitry. The voltage regulator is configured to control a voltage across the field device circuitry.