Induction Cooker Cooking Vessel Detection via Dual Current Sensing
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Solution Overview
Problem
Existing induction heating cookers face challenges in accurately detecting the presence of a cooking container due to factors like resistance, coil characteristics, and mechanical assembly scattering, leading to sensing errors.
Innovation Solution
The implementation of a device and method that includes a rectifying unit, switching units, and current sensing units to alternately apply DC voltage to the working coil, allowing a controller to determine the presence of a cooking container based on the ratio of first and second currents, thereby minimizing detection errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage division method is used to detect cooking container presence, then the detection method is simple, but the sensing accuracy deteriorates due to influence from resistance, working coil characteristics, gap variations, and mechanical assembly scattering
Solution Approach 1:
The patent changes the detection parameter from voltage division ratio to current ratio. By measuring the ratio of current through the working coil to current through the cooking container, the system achieves more stable and accurate detection that is less sensitive to mechanical assembly variations and gap changes, while maintaining relatively simple circuit implementation
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors the current ratio and adjusts detection thresholds dynamically. This feedback approach compensates for variations in resistance, coil characteristics, and mechanical assembly, thereby improving detection accuracy without significantly increasing system complexity
2Device complexity
If single current sensing is used, then the device complexity is low, but the detection reliability deteriorates due to sensitivity to resistance and coil variations
Solution Approach 1:
The patent segments the current measurement into two separate sensing paths: one measuring the current through the working coil and another measuring the current through the cooking container. By dividing the measurement function into separate sensing units, the system achieves more reliable detection that is less affected by individual component variations, while keeping each sensing unit relatively simple
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 enables accurate detection of the cooking container by sensing both currents, reducing errors caused by resistance, coil characteristics, and mechanical assembly scattering, ensuring reliable operation of the induction heating cooker.
Implementation Method 1
a rectifying unit for rectifying an AC voltage from a power supply to a DC voltage
Implementation Method 2
a working coil for induction heating of a cooking container placed thereon
Implementation Method 3
a cooking container itself is induction-heated by an eddy current flowing when a magnetic force line generated in a working coil passes through the cooking container
Data Source
AI summary
An induction heating cooker comprises a rectifying unit for rectifying an AC voltage from a power supply to a DC voltage and first and second switching units for switching to alternately apply the DC voltage from the rectifying unit to the working coil for driving the working coil.A device of sensing a cooking container in the induction heating cooker comprises a first current sensing unit configured to sense a first current flowing between the power supply and the rectifying unit, a second current sensing unit configured to sense a second current flowing to the working coil, and a controller configured to determine if the cooking container placed on the working coil is present based on the first and second currents.