Two-Wire Field Electronics With Buffer Voltage Energy Control

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Solution Overview

Problem

Field devices in automation technology face challenges in efficiently managing limited energy availability, leading to inaccurate power consumption estimates due to unknown power states of individual components, particularly in high-energy requirement sensors like those using microwaves or ultrasound.

Innovation Solution

The field device electronics incorporate a series controller, a quadrature regulator, parallel capacitance for energy storage, a control and evaluation unit, and a comparison circuit to detect buffer voltage and shunt current, enabling efficient energy management, decision-making, and module control, including error detection and power distribution based on detected voltages and currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If energy storage capacity is increased to ensure reliable operation under low voltage conditions, then system reliability is improved, but device complexity increases due to additional capacitors and control circuits

Engineering Contradiction:
Improvesystem reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The first capacitor C1 is pre-charged during normal operation to store energy in advance. When voltage drops occur, this pre-stored energy is immediately available to maintain operation of critical components, avoiding the need for complex real-time energy management systems.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The comparator circuit acts as an intermediary between the voltage monitoring system and the control unit. It simplifies the overall system architecture by providing a direct voltage threshold detection mechanism that triggers predefined responses, reducing the need for complex software-based voltage management.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If voltage threshold detection is implemented to prevent errors under low voltage conditions, then measurement precision is improved, but device complexity increases due to additional comparator circuits

Engineering Contradiction:
Improvevoltage detection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The voltage threshold detection function is extracted as a separate comparator circuit module, independent from the main control unit. This modular approach allows simple voltage threshold monitoring without burdening the main processor, maintaining measurement precision while keeping overall system complexity manageable.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The comparator circuit autonomously monitors voltage levels and automatically triggers predefined responses when thresholds are exceeded, without requiring continuous intervention from the main control unit. This self-service mechanism provides precise voltage detection while minimizing the processing burden on the main system.

Inventive Principle:
Principle #25Self-service

3Use of energy by moving object

If energy management control is enhanced to dynamically manage power distribution, then use of energy is improved, but device complexity increases due to additional control circuits and monitoring mechanisms

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

Solution Approach 1:

The control unit dynamically adjusts the operating states of various modules based on real-time voltage conditions and energy availability. Critical modules maintain operation while non-critical modules are deactivated during low-voltage events, optimizing energy usage without requiring complex power management hardware.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (such as switching modules on/off or adjusting power levels) in response to detected voltage conditions. This parameter-based control approach enables flexible energy management using simple threshold-based decisions rather than complex optimization algorithms.

Inventive Principle:
Principle #35Parameter changes

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 allows for accurate determination of energy status and efficient power distribution, ensuring reliable operation of field device electronics and connected sensors by dynamically managing energy storage and consumption, preventing errors and maintaining sensor functionality even under low voltage conditions.

Implementation Method 1

a first capacitor C1 connected in parallel to the shunt regulator 15, in particular connected in parallel to the cross-branch 17, for energy storage

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3729212B1Field device electronics for a field device used in automation engineering
Publication Date: 2022.01.05 ENDRESS & HAUSER GMBH & CO KG
  • EP3729212B1 patent drawingFigure 1

AI summary

Field device electronics (2) for a field device (1) used in automation engineering, having at least: a first and a second connection terminal (K1, K2) for connecting the field device electronics to a line (8), in particular a two-wire line, so that an input current (Iin) is suppliable to the field device electronics via the line and a terminal voltage (UK) is applicable to the first and second connection terminals; an in-phase regulator (13) for adjusting the input current, so that data, in particular a measured value and/or parameter values, are transferrable via the line on the basis of the input current; a quadrature regulator (15) connected downstream of the in-phase regulator; a first capacitance (C1), connected in parallel with the quadrature regulator, for storing energy; a supply circuit (4), connected in parallel with the quadrature regulator and the first capacitance, for providing an operating voltage (UB); a control and/or evaluation unit (5), connected downstream of the supply circuit and powered by the operating voltage (UB), which preferably comprises at least one microprocessor configured to capture a buffer voltage (Ubuffer) applied via the first capacitance or a variable dependent on said buffer voltage and to use the captured buffer voltage or a variable dependent thereon to make a decision about or for at least part of the field device electronics.