Single Inverter Driving Multiple Induction Heating Coils

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Solution Overview

Problem

Existing induction heating cookers require multiple inverters to drive multiple heating coils, increasing product size and manufacturing cost, and alternative configurations with a single inverter either generate noise or reduce output due to selective coil driving.

Innovation Solution

An electronic induction heating cooker utilizing a single inverter with three switching devices and a switching controller to manage different operation modes, allowing for simultaneous or alternating driving of multiple heating coils, thereby simplifying circuitry and eliminating the need for additional switches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple inverters are used to drive multiple heating coils, then the heating capability is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveheating capabilityVSAvoidcircuitry complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent merges multiple inverter functions into a single inverter by using one inverter to drive multiple heating coils through selective switching. The single inverter alternately connects to different heating coils based on control signals, enabling multiple coils to be heated simultaneously or alternately without requiring separate inverters for each coil, thus reducing device complexity while maintaining heating capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single inverter is designed to perform multiple functions by sequentially or simultaneously driving different heating coils. The inverter acts as a universal power source that can be dynamically allocated to various heating zones, replacing the need for dedicated inverters for each heating coil and simplifying the overall system architecture

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

2Device complexity

If a single inverter drives multiple heating coils alternately, then the device complexity is reduced, but noise is generated and output is reduced

Engineering Contradiction:
Improvecircuitry complexityVSAvoidnoise
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent implements periodic action by having the single inverter alternate between driving different heating coils in a cyclic manner. The inverter switches between coils at predetermined intervals, ensuring that not all coils are driven simultaneously. This periodic switching pattern reduces peak current demands and minimizes electromagnetic interference and noise generation compared to continuous simultaneous driving

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system employs dynamic control where the inverter's connection to heating coils is continuously adjusted based on operational requirements. The switching between coils is dynamically managed to optimize performance, allowing the system to adapt to different heating demands while reducing noise through controlled alternation rather than static simultaneous operation

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If additional switches are added to enable simultaneous coil driving, then the heating versatility is improved, but the device complexity increases

Engineering Contradiction:
Improveheating versatilityVSAvoidswitching device quantity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The single inverter is designed with multi-functionality to handle various heating configurations without requiring additional switching devices. By programmatically controlling the inverter's output connections, the system can achieve simultaneous or alternating coil driving modes, providing heating versatility while avoiding the complexity of adding more physical switches

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

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 reduces the volume and manufacturing cost of induction heating cookers, improves user satisfaction by enabling simultaneous heating of multiple coils, and enhances reliability by minimizing noise and switching losses.

Implementation Method 1

an inverter configured to comprise first, second and third switches connected in series between a positive power source terminal and a negative power source terminal and generate an alternating current (AC) voltage by switching the DC voltage

Methodology Applied
Scientific EffectElectrical switching:

Implementation Method 2

a first heater configured to be driven by the AC voltage so as to heat a first cooking container

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

a second heater configured to be connected in parallel to the first heater, and to be driven by the AC voltage so as to heat a second cooking container

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2739118B1Electronic induction heating cooker and output level control method thereof
Publication Date: 2017.11.08 LG ELECTRONICS INC
  • EP2739118B1 patent drawingFigure 1
  • EP2739118B1 patent drawingFigure 2
  • EP2739118B1 patent drawingFigure 3

AI summary

An electronic induction heating cooker (200) is provided. The electronic induction heating cooker (200) includes a rectifier (210) that rectifies an input voltage into a direct current (DC) voltage and output the DC voltage, an inverter (220) including first, second and third switches (S1, S2, S3) connected in series between a positive power source terminal and a negative power source terminal to generate an alternating current (AC) voltage by switching the DC voltage, a first heater (230) driven by the AC voltage so as to heat a first cooking container, a second heater (240) connected in parallel to the first heater (230) and driven by the AC voltage so as to heat a second cooking container, and a switching controller (270) that generates a switching signal for controlling the first and second heaters (230, 240) in accordance with a set of operating conditions input thereto and adjusts a duty cycle of the switching signal.