Induction Heating Coil Resonance Switching for Cooking and WPT
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Solution Overview
Problem
Induction heat cooking apparatuses face limitations in efficiently switching between cooking device heating and wireless power transfer modes, with existing systems often requiring separate coils and complex frequency adjustments, which can lead to inefficiencies and reduced performance.
Innovation Solution
The induction heat cooking apparatus incorporates a WPT capacitor connected in parallel to the resonance capacitor, controlled by mode conversion switches, allowing the same heating coil to operate in both cooking device heating and wireless power transfer modes by adjusting resonance frequency, and includes a PFC power converter for stable power output to variable loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate coils are used for heating and wireless power transfer, then both functions can be independently optimized, but device complexity and cost increase
Solution Approach 1:
The heating coil is designed to perform dual functions: traditional induction heating and wireless power transfer. By controlling the operating frequency and impedance matching, the same coil structure can efficiently operate in both heating mode (with cookware) and WPT mode (without cookware), eliminating the need for separate coils and reducing system complexity
Solution Approach 2:
The system dynamically switches between heating mode and wireless power transfer mode based on the presence of cookware. A detection circuit identifies whether cookware is placed on the cooktop and automatically adjusts the operating parameters (frequency, power level) to optimize performance for the current mode, enabling one coil to adaptively serve multiple purposes
2Adaptability or versatility
If frequency adjustments are made to switch between heating and WPT modes, then mode switching is enabled, but system stability and performance degrade
Solution Approach 1:
The system performs preliminary detection of cookware presence before initiating heating or WPT operations. The detection circuit pre-identifies the operational mode required, allowing the control system to proactively configure optimal parameters (frequency, power level, impedance matching) for the detected mode, preventing instability that would arise from abrupt frequency switching during operation
Solution Approach 2:
The system incorporates feedback mechanisms that continuously monitor operating conditions and adjust parameters in real-time. The control circuit receives feedback from detection circuits about cookware presence and system state, automatically adjusting operating frequency and power levels to maintain optimal performance and stability in both heating and WPT modes without manual intervention
3Adaptability or versatility
If resonance capacitor is connected in parallel with WPT capacitor, then wireless power transfer is enabled, but power factor and stability deteriorate with variable loads
Solution Approach 1:
A power factor correction (PFC) circuit is introduced as an intermediary component between the resonance circuit and the load. The PFC circuit actively compensates for reactive power and stabilizes the power factor, enabling the system to maintain stable power output and high efficiency even when operating in WPT mode with variable loads or when the resonance capacitor is connected in parallel with the WPT capacitor
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 solution enables efficient switching between heating and wireless power transfer modes, improving energy efficiency and power factor, allowing for stable operation with variable loads and maintaining high efficiency and power factor performance.
Implementation Method 1
high frequency current flows through a working coil or a heating coil, which is provided in the induction heat cooling apparatus. When the high frequency current flows through the working coil or the heating coil, lines of strong magnetic force are generated. The lines of the magnetic force generated in the working coil or the heating coil generate eddy current when passing through a cooking device. Thus, since the eddy current flows through the cooking device, heat is generated to heat a container itself.
Implementation Method 2
a WPT capacitor, which is not connected to a resonance capacitor or is connected in parallel to the resonance capacitor as the induction heat cooking apparatus operates in a cooking device heating mode or a wireless power transfer mode
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5b
AI summary
Provided is an induction heat cooking apparatus. The induction heat cooking apparatus includes a rectifier configured to convert an AC voltage supplied from an external power source into a DC voltage, an inverter configured to receive the voltage from the rectifier to supply current to heating coils, the heating coils configured to generate magnetic fields when the current flows through the inverter, a resonance capacitor including both DC terminals through which the voltage is outputted from rectifier and a plurality of capacitors connected in series to each other between the heating coils, a wireless power transfer (WPT) capacitor connected in parallel to the resonance capacitor, and a mode conversion switch configured to determine whether to connect the resonance capacitor to the WPT capacitor in parallel.