Adaptive Frequency Control for Induction Cooker Power Transfer
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Solution Overview
Problem
Induction cookers face challenges in accurately measuring and maintaining the resonance frequency, leading to inefficient power transfer due to the fixed operating frequency range, which does not account for varying cooking vessel materials and positions.
Innovation Solution
A control device and method that adapt the operating frequency range by analyzing feedback signals after power signal application, adjusting threshold values based on the step response of the induction coil, allowing for variable frequency ranges tailored to different cooking vessels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed operating frequency range is used for the power signal, then the device structure is simple and easy to control, but power transfer efficiency decreases because it does not adapt to different cooking vessel materials and positions
Solution Approach 1:
The patent applies dynamics by making the operating frequency range adaptive rather than fixed. The controller dynamically adjusts the frequency range based on real-time feedback from the cooking vessel, allowing the system to optimize power transfer efficiency for different vessel materials and positions while maintaining a relatively simple overall device structure.
Solution Approach 2:
The patent changes the frequency parameter dynamically based on detected cooking vessel characteristics. By measuring feedback signals and determining optimal frequency ranges accordingly, the system adapts the operating frequency to maximize power transfer efficiency for each specific cooking scenario.
2Power
If the operating frequency is increased to deliver more power, then power delivery improves, but the impedance of the induction coil decreases causing current to increase beyond safe limits
Solution Approach 1:
The patent uses feedback mechanisms to monitor the state of the induction coil and cooking vessel system. By continuously measuring feedback signals and using this information to adjust the operating frequency, the system can deliver optimal power while preventing current from exceeding safe limits, thus maintaining reliability.
Solution Approach 2:
The patent applies preliminary anti-action by setting a configurable operating frequency range that is higher than the resonance frequency but bounded by a maximum frequency threshold. This pre-established frequency ceiling prevents the system from operating at frequencies that would cause excessive current, thereby proactively avoiding safety issues before they occur.
3Power
If the operating frequency is set at the resonance frequency for maximum power transfer, then power delivery is maximized, but it becomes difficult to accurately measure and maintain the resonance frequency
Solution Approach 1:
The patent applies preliminary action by pre-configuring an operating frequency range that starts at the resonance frequency and extends to a maximum frequency. Instead of attempting to precisely measure and maintain a single resonance frequency point, the system prepares a frequency range in advance that ensures optimal power transfer while being more practical for control and measurement.
Solution Approach 2:
The patent changes from a fixed frequency point approach to a configurable frequency range approach. By allowing the operating frequency to vary within an optimized range based on feedback signals, the system maintains high power transfer efficiency while avoiding the measurement and maintenance difficulties associated with precisely locking onto a single resonance frequency.
4Reliability
If a maximum frequency limit is set to prevent excessive current, then device safety is improved, but power delivery capability is reduced
Solution Approach 1:
The patent applies dynamics by making the frequency limit adaptive rather than purely restrictive. The maximum frequency is configured based on system characteristics, and the actual operating frequency is dynamically adjusted within the safe range to maximize power delivery capability while maintaining device safety.
Solution Approach 2:
The patent optimizes the frequency parameter by setting it within a configurable range rather than at a fixed maximum limit. This allows the system to operate at the highest safe frequency for each specific cooking scenario, thereby maximizing power delivery capability while respecting safety constraints.
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 adaptive approach enhances power transfer efficiency by dynamically adjusting the frequency range based on the cooking vessel's properties, improving performance across various materials and positions.
Implementation Method 1
a high frequency power signal is provided to an induction coil. This generates a magnetic field around the induction coil, which is magnetically coupled to a conductive cooking vessel, such as a pan, placed over the induction coil. The magnetic field then generates eddy currents in the cooking vessel, causing the cooking vessel to heat.
Implementation Method 2
The magnetic field then generates eddy currents in the cooking vessel, causing the cooking vessel to heat.
Data Source
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AI summary
The present invention provides a control device (1) for an induction cooker (2, 20), the control device (1) comprising a driving circuit (4, 26) configured to controllably drive an induction coil (6) of the induction cooker (2, 20), a controller (7, 27) coupled to the driving circuit (4, 26) and configured to control the driving circuit (4, 26) with a control signal (8, 28) to drive the induction coil (6) with a power signal (5) of a configurable operating frequency, which is higher than a first initial threshold value and lower than a second initial threshold value, and a first measurement device (9, 29) configured to measure a feedback signal (10, 30, 56) at the induction coil (6) and provide the measured feedback signal (10, 30, 56) to the controller (7, 27). The controller (7, 27) is configured to adapt the first threshold value (40, 41) and the second threshold value (42, 43) based on the feedback signal (10, 30, 56), which is measured in a predetermined time period (50) after application of the power signal (5). The present invention further provides a respective method and an induction cooker.