Induction Heating Coil Phase Detection for Pot Misalignment
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Solution Overview
Problem
Induction heating devices face challenges in accurately detecting misalignment of objects on heating coils without the use of sensors, which can increase costs, and methods based on driving frequency are difficult to implement across various usage situations due to variations in material and size of the objects.
Innovation Solution
An induction heating device that utilizes a processor to measure the phase delay of alternating current flowing through the heating coil, calculates a reference phase, and compares it with a dynamically adjusted threshold to determine misalignment, eliminating the need for dedicated sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is used to detect pot misalignment, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical sensor-based detection system with an electrical measurement system. The control device measures the phase of the current flowing through the heating coil to detect pot misalignment, eliminating the need for physical sensors and reducing device complexity while maintaining detection accuracy.
Solution Approach 2:
The patent introduces the phase of current as an intermediary parameter to indirectly detect pot misalignment. Instead of directly measuring pot position with a sensor, the system measures the current phase which changes in response to pot misalignment, providing a cost-effective detection mechanism.
2Ease of operation
If a fixed threshold based on driving frequency is used, then ease of operation is improved, but measurement precision deteriorates due to variations in pot material and size
Solution Approach 1:
The patent implements a dynamic threshold adjustment mechanism where the reference value is not fixed but is calculated based on the actual driving frequency and other operational parameters. This allows the system to adapt to different pot materials, sizes, and heating conditions, maintaining high measurement precision across various usage situations while remaining easy to operate.
Solution Approach 2:
The patent changes the detection parameter from a fixed frequency-based threshold to a dynamically calculated phase-based threshold. By calculating the reference phase according to the actual driving frequency and comparing the measured phase against this dynamic reference, the system achieves accurate detection across different pot types without requiring manual parameter adjustments.
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
Accurately detects misalignment of objects on the heating coil in all usage situations without additional hardware, ensuring efficient and cost-effective operation by adapting the threshold based on the control signal and object characteristics.
Implementation Method 1
a heating coil configured to inductively heat an object to be heated based on an alternating current flowing therethrough
Implementation Method 2
an inverter configured to convert a direct current voltage into an alternating current voltage by turning on or off a plurality of switching devices therein and supply the alternating current voltage to the heating coil
Data Source
AI summary
Provided is an induction heating device configured to output, to an inverter, an inverter control signal for controlling the inverter, obtain a detection signal corresponding to a detected alternating current, measure, as an actual phase, a delay in an input time point at which the detection signal corresponding to the inverter control signal is obtained relative to an output time point at which the inverter control signal is output, calculate, based on the inverter control signal, a reference phase including a delay in the input time point relative to the output time point in a state where the object to be heated is misaligned above the heating coil, calculate a threshold by subtracting a predetermined offset from the reference phase, and determine whether the object to be heated is misaligned above the heating coil by comparing the actual phase with the threshold.