AC Input Protection Using Voltage Frequency Analysis

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Solution Overview

Problem

Electrical apparatuses connected to multi-phase AC power distribution networks face performance issues due to excessive input currents, which can lead to component overheating, malfunction, or degradation, especially in 'stiff grid' scenarios, where prior solutions involving additional impedances increase costs and waste energy.

Innovation Solution

An electrical apparatus with an impedance network connected between input nodes and ground, monitored by a control system that analyzes voltage signals to determine frequency content and properties, allowing for reduction of power or disconnection from the network if performance conditions are met, thereby protecting the apparatus without relying on current sensors or additional impedances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional impedances are added to protect electrical apparatus from excessive input currents, then reliability is improved, but device complexity and cost increase

Engineering Contradiction:

Improveprotection from excessive currentsVSAvoidadditional impedances

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces physical impedance components with a control system that uses voltage signal analysis and frequency content determination to detect and respond to excessive current conditions. The control system monitors voltage at input nodes, analyzes frequency content, and triggers protection actions without requiring additional passive impedance elements in the electrical path.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electrical apparatus uses its own existing voltage sensing capability to monitor input conditions and detect excessive current scenarios. The control system leverages voltage signals already present in the system, analyzing their frequency content to determine when protection is needed, eliminating the need for separate sensing or impedance components.

Inventive Principle:

Principle #25Self-service

2Reliability

If additional impedances are added to protect electrical apparatus, then reliability is improved, but energy loss increases

Engineering Contradiction:

Improveprotection from excessive currentsVSAvoidenergy waste

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces power-consuming impedance components with a control system that performs voltage signal analysis. The control system determines frequency content of voltage signals and identifies excessive current conditions through computational analysis rather than physical impedance, eliminating continuous energy loss associated with passive protective components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The control system performs periodic monitoring of voltage signals and frequency content analysis only when needed to detect excessive current conditions. This on-demand protection approach consumes energy only during monitoring and decision-making cycles rather than continuously dissipating energy through impedance components.

Inventive Principle:

Principle #19Periodic action

3Measurement precision

If current sensors are used to detect excessive currents, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvecurrent detection accuracyVSAvoidcurrent sensors

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses voltage signals as an intermediary to indirectly detect excessive current conditions. Instead of directly measuring current with sensors, the control system analyzes voltage signals at input nodes and determines frequency content, using voltage as a mediator to infer current-related protection needs without direct current measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent substitutes current sensors with a control system that performs voltage analysis and frequency content determination. The control system processes voltage signals mathematically to identify excessive current scenarios, replacing physical sensing hardware with computational analysis of existing voltage measurements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11777305B2Protection of an electrical apparatus

Publication Date: 2023.10.03 EATON INTELLIGENT POWER LTD

AI summary

An electrical apparatus configured to electrically connect to a multi-phase alternating current (AC) electrical power distribution network includes: an input electrical network including: a plurality of input nodes, each configured to electrically connect to one phase of the multi-phase AC electrical power distribution network; at least one non-linear electronic component electrically connected to the input electrical network; an impedance network electrically connected between the input electrical network and ground; and a control system configured to: access a voltage signal that represents a voltage over time at the input electrical network; determine a frequency content of the voltage signal; determine a property of the frequency content; and determine whether an input current performance condition exists in the electrical apparatus based the property of the frequency content.