Multi-Coil Induction Heating Load Detection via Dual-Current Switching
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Solution Overview
Problem
Multi-coil induction heating devices face challenges in implementing energy-saving and accurate load detection in a short time, as existing methods are inefficient and lack precision.
Innovation Solution
The induction heating device employs a controller that supplies a first detection current to heating coils, determines the presence of a load, and if none is detected, switches to a second detection current with a higher current value to ensure accurate load detection, utilizing a switching unit to connect or disconnect coils as needed, and sequentially identifies each coil when a load is present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single detection current is used for load detection, then the detection process is simple, but the detection accuracy and energy efficiency are insufficient
Solution Approach 1:
The detection current is segmented into multiple levels (first detection current and second detection current with different magnitudes). The controller selectively applies different detection current levels based on detection needs, dividing the detection process into stages to improve accuracy without requiring complete system redesign
Solution Approach 2:
The detection current magnitude is made dynamic rather than fixed. The controller adjusts the detection current level during operation, switching between first and second detection currents based on whether a load is detected, allowing the system to adapt its detection strategy to different operational states
2Measurement precision
If a high detection current is always used, then the detection accuracy is high, but the energy consumption increases
Solution Approach 1:
The detection process uses periodic action with alternating current levels. The controller first applies a lower first detection current, and only switches to the higher second detection current when necessary (when no load is detected with the first current). This periodic variation in detection current magnitude reduces overall energy consumption while maintaining detection accuracy
Solution Approach 2:
The system applies partial detection action first using the first detection current to cover typical detection scenarios. The second detection current is reserved as an additional measure only when needed (when no load is detected initially), avoiding the excessive energy consumption of always using the higher current
3Measurement precision
If multiple detection currents are used, then the energy efficiency and detection accuracy improve, but the control complexity increases
Solution Approach 1:
The controller uses feedback from the detection process to determine which detection current level to apply next. When a load is detected with the first detection current, the controller stops detection. When no load is detected, the controller feeds back the decision to switch to the second detection current. This feedback mechanism automates the complex control logic, maintaining operational simplicity
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 quick and accurate load detection with reduced energy consumption, ensuring efficient operation and precise identification of heating coils for induction heating.
Implementation Method 1
an induction heating device that inductively heats a load, such as a metal cooking pot, placed on a top panel
Implementation Method 2
a plurality of heating coils provided below the top panel
Implementation Method 3
detects a change in an electric signal on a conduction path which connects a power source of the heating cooker to each of the heating coils
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
In a multi-coil induction heating device, driver (4) supplies a first detection current which is a high frequency power to a plurality of heating coils (3) provided below a top panel on which a load is placed. Controller (50) determines whether a load is placed above the plurality of heating coils (3) based on an electric signal in response to the first detection current. When controller (50) determines that a load is not placed above the plurality of heating coils (3), driver (4) supplies a second detection current, which is a high frequency power and has a larger current value than the first detection current, to the plurality of heating coils (3). Controller (50) determines whether a load is placed above the plurality of heating coils (3) based on an electric signal in response to the second detection current. According to this aspect, energy-saving and accurate load detection is possible in a short time in the multi-coil induction heating device.