Induction Heating Device Container Sensing via Resonance Current
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Solution Overview
Problem
Existing induction heating devices face challenges in accurately sensing a cooking container due to high power consumption and low accuracy, especially when an adjacent working coil operates or input voltage changes, leading to inefficient energy use and reduced reliability.
Innovation Solution
The induction heating device incorporates an inverter unit, a sensor to measure current, and a controller that controls the inverter unit based on current values to determine the presence of a container through resonance and voltage conversion, allowing for efficient energy charging and stable sensing operations regardless of adjacent coil operations or input power changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If container sensing is performed only at zero-point time point, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent applies periodic action by performing container sensing at multiple time points including zero-point and peak points of the resonant current waveform. This periodic multi-point measurement approach improves measurement precision while maintaining manageable device complexity through systematic timing selection.
2Measurement precision
If continuous container sensing is performed, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The patent implements periodic sensing at specific waveform time points (zero-point and peak point) rather than continuous sensing. This periodic approach maintains measurement precision by sampling at critical moments while significantly reducing power consumption by avoiding constant measurement operations.
Solution Approach 2:
The system performs preliminary action by pre-determining the resonant frequency and selecting optimal measurement time points (zero-point and peak point) before actual container sensing. This preliminary setup enables accurate sensing at discrete moments, reducing the need for continuous power-intensive measurements.
3Device complexity
If sensing is performed without considering input voltage changes, then device complexity is reduced, but reliability deteriorates
Solution Approach 1:
The patent implements feedback by monitoring input voltage changes and adjusting the resonant frequency determination accordingly. When input voltage varies, the system detects this change and adapts the sensing parameters, ensuring reliable operation across different voltage conditions while maintaining manageable control complexity through voltage-change detection thresholds.
4Device complexity
If adjacent working coil operation is not considered, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The system uses feedback to detect changes in resonant frequency caused by adjacent coil operations. By monitoring frequency shifts and comparing them against predetermined ranges, the system can distinguish between frequency changes due to adjacent coils versus those indicating container presence, maintaining measurement precision without requiring complex interference cancellation systems.
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 enables the induction heating device to operate with low power consumption, improve accuracy, and enhance user satisfaction by reducing energy waste and ensuring reliable container sensing, even under varying conditions.
Implementation Method 1
a sensor configured to measure a current applied to the induction heating circuit
Implementation Method 2
An induction heating device may cause a high-frequency current to flow in a working coil or a heating coil. The high-frequency current may generate a strong magnetic field line.
Implementation Method 3
when the magnetic field line passes through a cooking container placed on the heating coil, an eddy current may be generated in the cooking container.
Implementation Method 4
as a current is applied to the heating coil, an induction heating phenomenon may occur in the cooking container made of a magnetic material. Heat generated by induction heating may increase a temperature of the cooking container.
Implementation Method 5
The controller includes a switch driving circuit configured to control operation of the inverter unit and to allow a resonance of the current
Data Source
AI summary
An induction heating device includes an induction heating circuit, a sensor configured to measure current applied to the induction heating circuit, and a controller. The controller includes: a switch driving unit configured to control operation of an inverter unit and to allow a resonance of the current, a container sensing unit, and a control unit. The container sensing unit is configured to: convert a first current value before the resonance into a first voltage value; control the switch driving unit to charge a working coil; compare the first voltage value with a resonance reference value; convert a second current value after the resonance into a second voltage value; generate one or more output pulses; and compare the second voltage value with a count reference value. The control unit is configured to determine whether an object is present on the working coil based on the one or more output pulses.