Induction Heating Container Sensing via Resonant Current
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Solution Overview
Problem
Induction heating devices face challenges in accurately sensing containers with low power consumption and high accuracy, especially when an adjacent working coil operates or input power changes, leading to reduced accuracy and increased power consumption.
Innovation Solution
The method involves an induction heating device with a switch driving unit, an induction heating circuit driven by an inverter unit, a sensor for current sensing, a resonant current conversion unit, a shutdown comparison unit, a shutdown circuit unit, and a control unit that determines container presence by comparing voltage values with reference values and generating output pulses based on resonance and count or duty time, allowing for efficient container sensing regardless of adjacent coil operation or power changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If container sensing is performed continuously or frequently, then sensing accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic container sensing at specific time points (zero-point time points of input voltage) rather than continuous sensing. The control unit determines container presence by detecting voltage fluctuations at these periodic intervals, which reduces power consumption while maintaining adequate sensing accuracy through strategic sampling of the voltage waveform.
2Use of energy by moving object
If sensing is performed only at zero-point time points, then power consumption is reduced, but sensing accuracy deteriorates
Solution Approach 1:
The patent uses feedback from voltage fluctuation detection at zero-point time points to determine container presence. The control unit monitors voltage fluctuations caused by container insertion or removal events and uses this feedback information to accurately detect container status without requiring continuous sensing, thereby maintaining accuracy while reducing power consumption.
3Adaptability or versatility
If input voltage changes or adjacent working coils operate, then system versatility is improved, but container sensing accuracy deteriorates
Solution Approach 1:
The patent dynamically adapts the container sensing operation based on system conditions. The control unit determines whether to perform container sensing based on the operational state of adjacent working coils and input voltage conditions. By dynamically adjusting sensing operations to match system conditions, the patent maintains accurate container detection while enabling versatile operation under varying conditions.
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 reduces power consumption, improves response characteristics, and enhances the accuracy and reliability of container sensing, preventing over-currents and noise, while maintaining stable operation across varying input conditions.
Implementation Method 1
the switching unit 62 supplies a resonant current to the working coil through a switching operation
Implementation Method 2
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
Heat generated by induction heating
Implementation Method 6
The current conversion unit 66 measures a resonant current flowing through the working coil 63 and transmits a voltage fluctuation waveform to the control unit 65
Data Source
AI summary
A method for sensing a container includes: charging an induction heating circuit; sensing a current applied to the induction heating circuit, converting a current value of the current into a first voltage value; comparing the first voltage value with a resonance reference value; generating a resonance of the current; sensing a resonant current generated in the induction heating circuit; converting the resonant current into a second voltage value; comparing the second voltage value with a count reference value; generating one or more output pulses; comparing a count of the one or more output pulses with a reference count, or comparing an on-duty time of the one or more output pulses with a reference time; and based on (i) the comparison of the count with the reference count or (ii) the comparison of the on-duty time with the reference time, determining whether an object is present on a working coil.