Load Detection Circuit for Automatic Appliance Mode Switching

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Solution Overview

Problem

Existing appliances, such as induction cookers, require manual user selection of load type, leading to potential misuse and risk of damage due to incorrect operation modes.

Innovation Solution

A detection circuit comprising capacitive and inductive components that automatically determine the type of load by analyzing AC signal directions and zero-crossing points, enabling the appliance to switch to corresponding operation modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual user selection of load type is required, then user control over operation mode is maintained, but user safety and convenience deteriorate due to potential misuse and incorrect selection

Engineering Contradiction:
Improveautomatic load type recognitionVSAvoiddetection circuit complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The detection circuit automatically detects and identifies load types without requiring user intervention. The system self-determines whether the connected device is a heating load or power transmission load by analyzing AC signal characteristics, and automatically switches operation modes accordingly, making the system serve itself rather than requiring manual user configuration

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The detection circuit identifies load types by detecting changes in AC signal parameters such as current direction, voltage zero-crossing points, and current zero-crossing points. By monitoring these parameter variations, the system can distinguish between different load types and appropriately adjust operation modes without user input

Inventive Principle:
Principle #35Parameter changes

2Reliability

If automatic load type detection is implemented, then user safety and convenience are improved, but device complexity increases due to additional detection circuits

Engineering Contradiction:
Improveappliance safetyVSAvoiddetection circuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detection circuit serves multiple functions: it detects load type, determines operation mode, and controls appliance safety. By integrating these functions into a single detection system that analyzes AC signal characteristics, the patent achieves multi-functionality without proportionally increasing complexity, as the same detection mechanism supports multiple safety and operational determinations

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The detection circuit acts as an intermediary between the power source and the load. It monitors AC signal parameters and provides information to the control system, enabling safe and appropriate operation without direct user intervention. This intermediary function enhances reliability by preventing incorrect operation modes while maintaining manageable complexity through a dedicated detection layer

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If detection circuit automatically determines operation mode, then misuse and potential damage are prevented, but measurement precision requirements increase for AC signal analysis

Engineering Contradiction:
Improvemisuse and damage riskVSAvoidAC signal direction detection accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The detection circuit continuously monitors AC signal characteristics and provides feedback to the control system. By detecting current direction relative to voltage zero-crossing points and comparing these measurements against predetermined thresholds, the system can reliably distinguish between heating loads and power transmission loads, preventing misuse while maintaining practical measurement precision requirements

Inventive Principle:
Principle #23Feedback

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

Enhances user safety and experience by allowing the appliance to automatically recognize load types and operate in appropriate modes, preventing misuse and potential damage.

Implementation Method 1

the inductive component is configured to perform filtering or compensation processing on an AC signal output from the AC power source

Methodology Applied
Scientific EffectFiltering: Filter (electronic)

Implementation Method 2

The detection component is configured to detect a first alternating current (AC) signal of the first branch and a second AC signal of the second branch, determine a first direction of the first AC signal and a second direction of the second AC signal

Methodology Applied
Scientific EffectElectrical signal detection:

Data Source

PatentEP3998484B1Detection circuit, electrical appliance and control method
Publication Date: 2024.04.03 GUANGDONG MIDEA WHITE HOME APPLIANCE TECH INNOVATION CENT CO LTD
  • EP3998484B1 patent drawingFigure 1~2
  • EP3998484B1 patent drawingFigure 3~5
  • EP3998484B1 patent drawingFigure 6

AI summary

The embodiments of the present application disclose a detection circuit, an electrical appliance and a control method. The detection circuit at least comprises: a first capacitive component, a second capacitive component, a load to be detected and a detection component; the first capacitive component and said load are connected in series to form a first branch circuit; the first branch circuit is in parallel with a second branch circuit comprising the second capacitive component; and the detection component is used for detecting a first alternating current signal of the first branch circuit and a second alternating current signal of the second branch circuit, determining a first direction of the first alternating current signal and a second direction of the second alternating current signal, and determining the type of said load on the basis of the first direction and the second direction.