Isolated Digital Detection Circuit for Power Relay Verification

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing systems for verifying the disconnection of power relays in high-voltage energy storage systems are not isolated, leading to safety concerns and increased complexity and cost due to the use of analog sensing methods.

Innovation Solution

A digital detection circuit using voltage drop resistors, diodes, optocouplers, and pull-down/pull-up resistors provides an isolated and cost-effective means to test the proper functioning of relays, allowing for safer and more efficient verification of disconnect means without the need for additional isolated power supplies or microprocessors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If analog sensing is used to verify relay disconnection, then the system can detect current flow, but the system is not isolated from high-voltage lines, requiring additional isolated power supplies and increasing complexity and cost

Engineering Contradiction:

ImprovesafetyVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary detection circuit that bridges the isolated high-voltage side and low-voltage side through optical coupling. The optocoupler acts as a mediator that allows signal transmission without direct electrical connection, eliminating the need for additional isolated power supplies while maintaining safety isolation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional analog electrical sensing mechanism with a digital optical sensing mechanism. Instead of using analog current detection that requires isolated power supplies, the system uses digital optocoupler-based detection that inherently provides isolation and eliminates the need for additional power supply infrastructure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If analog sensing systems are used, then relay disconnection can be detected, but additional parts make the system more expensive and complex

Engineering Contradiction:

Improverelay verificationVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs inexpensive digital components (optocouplers, resistors, capacitors) that are cheaper and simpler than traditional analog sensing systems. These digital components are readily available, low-cost parts that eliminate the need for expensive isolated power supplies while providing reliable relay verification functionality.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Device complexity

If non-isolated inverters are used to reduce complexity, then the inverter design is simpler, but safety concerns arise when high-voltage current may be running through easily-accessible areas

Engineering Contradiction:

Improveinverter designVSAvoidsafety risk

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The detection circuit serves as an intermediary that provides safe monitoring of high-voltage relay status without requiring physical access to or direct connection with high-voltage current paths. The optical coupling mechanism allows the low-voltage control circuitry to safely monitor high-voltage conditions through isolation barriers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct electrical contact-based sensing with optical sensing through optocouplers. This substitution eliminates the need for physical proximity to high-voltage current paths, allowing safe monitoring without exposing operators or control circuitry to harmful high-voltage conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The digital detection circuit ensures safe and reliable verification of relay disconnection in both single-phase and multi-phase systems, reducing costs and parts complexity while enhancing safety by providing a fully isolated testing mechanism.

Implementation Method 1

The detection circuit may be composed of voltage drop resistors, voltage drop diodes, an optocoupler, and other pull-down and pull-up resistors and filter capacitors

Methodology Applied

Scientific EffectOptocoupler:

Implementation Method 2

The detection circuit may be composed of voltage drop resistors, voltage drop diodes

Methodology Applied

Scientific EffectVoltage drop: Ohm's Law

Data Source

PatentUS11874327B2Automated digitized system and methods for verifying power relay disconnect

Publication Date: 2024.01.16 SONNEN INC

AI summary

Systems and methods for automatically verifying that power relays have been disconnected include relays arranged between two power sources. Test nodes are positioned between the relays on each line, and feed into a detection circuit. Voltage drop resistors, voltage drop diodes, an optocoupler, and additional resistors and capacitors are used to provide voltage isolation for the detection circuit. Relays are methodically opened and closed to check the individual functioning of each relay, and a digital signal generated from the detection circuit. The design of the system with detection circuit isolation provides a safer and lower cost system for verifying that relays are operating correctly, with less costly components than traditional systems.