Induction Heating Coil Detection via Semiconductor Switching

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Solution Overview

Problem

Conventional zone free type induction heating and wireless power transferring devices face issues with noise generation during relay switching operations, large circuit volume due to group relays and target object detection circuits, and reduced detection speed and reliability.

Innovation Solution

The use of a control unit and semiconductor switches to detect target objects by controlling inverter units and switches, allowing for independent coil operation and reducing the need for relays and detection circuits, thereby minimizing noise and circuit volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If relay switching operations are used for target object detection, then circuit switching operation can be performed, but noise is generated during switching

Engineering Contradiction:

Improvecircuit switching operationVSAvoidnoise

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent replaces mechanical relay switching with electronic control using a control unit and semiconductor switches. This substitution eliminates the mechanical contact closure that generates noise, while maintaining the circuit switching functionality through electronic signal control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent removes the relay components from the circuit and extracts only the essential switching function, implementing it through a control unit that directly controls semiconductor switches connected to working coils, thereby eliminating the noise source.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If group relays and target object detection circuits are added, then target object detection capability is improved, but circuit volume increases

Engineering Contradiction:

Improvetarget object detection capabilityVSAvoidcircuit volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The control unit serves multiple functions simultaneously: it controls semiconductor switches for circuit switching, detects target objects by monitoring working coil states, and manages overall device operation. This multi-functionality eliminates the need for separate detection circuits and group relays, reducing circuit volume.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the target object detection function with the existing control unit and working coil structure. The detection capability is integrated into the control logic rather than being implemented through separate hardware circuits, thereby reducing overall circuit volume.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If conventional detection algorithms are used, then target object detection can be performed, but detection speed and reliability are reduced

Engineering Contradiction:

Improvedetection reliabilityVSAvoiddetection speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The control unit continuously monitors the states of working coils and maintains readiness to detect target objects before actual heating begins. This preliminary monitoring ensures immediate detection when a target object is placed, improving both detection speed and reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback monitoring of working coil states through the control unit. This real-time feedback mechanism enables rapid and reliable detection of target objects by constantly comparing actual coil performance against expected parameters.

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

This approach improves target object detection speed, reliability, and user satisfaction by enabling quiet operation and reducing the overall device volume, while enhancing space utilization.

Implementation Method 1

The induction heating method is a method of generating an eddy current in an object to be heated (for example, a cooking container) that is made of a metal component by using a magnetic field generated around a coil when a predetermined magnitude of high-frequency power is applied to the coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

generating an eddy current in an object to be heated

Methodology Applied

Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

heating the object to be heated itself

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11533787B2Induction heating and wireless power transferring device having improved target object detection algorithm

Publication Date: 2022.12.20 LG ELECTRONICS INC

AI summary

An induction heating and wireless power transferring device that includes: a first working coil and a second working coil that are coupled in parallel; a rectification unit configured to rectify alternating current (AC) power to direct current (DC) power; a first inverter unit configured to convert the DC power into resonant current, and apply the converted resonant current to the first working coil or the second working coil; a first switch coupled to the first working coil and configured to turn on or off the first working coil; a second switch coupled to the second working coil and configured to turn on or off the second working coil; and a control unit configured to control the first inverter unit, the first switch, or the second switch to detect whether a target object is located on the first working coil or the second working coil.