Induction Hob Frequency Control for Continuous Power and Noise Reduction
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Solution Overview
Problem
Existing cooking appliances, such as induction hobs, face challenges in achieving continuous power output while minimizing intermodulation noise and ensuring energy efficiency, particularly in adjusting heating power to operator-selected levels without generating audible noise.
Innovation Solution
A cooking appliance device with at least two heating frequency units and a control unit that adjusts the average output power by changing the frequency of one unit while maintaining operation of the other, operating at fixed or pulsed frequencies to avoid intermodulation noise, and adjusting duty cycles to maintain constant output power and reduce flicker levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If both heating frequency units are operated with identical frequency in first time period and one is switched off in second time period to adjust average output power, then the heating power can be adjusted to operator-selected levels, but the power output becomes discontinuous and intermodulation noise is generated
Solution Approach 1:
The patent applies periodic frequency switching where each heating frequency unit alternates between operating at a first frequency and a second frequency in periodic time periods. This periodic action allows the system to achieve average output power corresponding to operator-selected heating levels while both units remain continuously operational, eliminating the discontinuity and intermodulation noise associated with completely switching off units.
Solution Approach 2:
The patent changes the operating frequency parameter of the heating frequency units dynamically. By switching between a first frequency and a second frequency in periodic time periods, the system adjusts the average output power to match operator-selected heating levels. This parameter change approach allows continuous power delivery while avoiding the need to completely switch off units, thereby maintaining power output continuity and eliminating intermodulation noise.
2Use of energy by moving object
If heating frequency units operate at high frequencies to achieve desired heating power, then energy efficiency improves, but audible intermodulation noise is generated
Solution Approach 1:
The patent employs periodic switching between different operating frequencies to eliminate intermodulation noise while maintaining high-frequency operation for energy efficiency. By alternating between a first frequency and a second frequency in periodic time periods, the system ensures that both heating frequency units operate at high frequencies most of the time, preserving energy efficiency, while the periodic frequency variation prevents the generation of audible intermodulation noise.
Solution Approach 2:
The patent dynamically changes the frequency parameter of the heating frequency units between a first frequency and a second frequency in periodic time periods. This parameter change strategy allows the units to operate at high frequencies for energy efficiency while the periodic variation in frequency prevents the generation of audible intermodulation noise, thus resolving the contradiction between energy efficiency and noise generation.
3Power
If one heating frequency unit is switched off temporarily to adjust average output power, then power levels can be controlled, but the reliability of continuous heating is reduced
Solution Approach 1:
The patent applies periodic frequency switching where both heating frequency units remain continuously operational, alternating between a first frequency and a second frequency in periodic time periods. This eliminates the need to completely switch off units, thereby maintaining continuous heating reliability while still achieving the desired average output power levels through the periodic frequency variation.
Solution Approach 2:
The patent changes the frequency parameter of the heating frequency units between a first frequency and a second frequency in periodic time periods, allowing both units to remain continuously operational. This parameter change approach enables control of average output power while maintaining continuous heating reliability, as neither unit is completely switched off.
4Stability of the object's composition
If both heating frequency units operate simultaneously at different frequencies, then continuous power output is achieved, but intermodulation noise increases
Solution Approach 1:
The patent employs periodic switching where both heating frequency units operate simultaneously but alternate between a first frequency and a second frequency in periodic time periods. This periodic frequency variation allows both units to remain operational for continuous power output while the periodic switching between frequencies prevents the generation of audible intermodulation noise, thus resolving the contradiction between power continuity and noise generation.
Solution Approach 2:
The patent dynamically changes the frequency parameter of both heating frequency units in periodic time periods, with each unit alternating between a first frequency and a second frequency. This parameter change strategy enables both units to operate simultaneously for continuous power output while the periodic frequency variation prevents intermodulation noise, resolving the contradiction between power continuity and noise generation.
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 the most continuous power output possible, eliminates audible intermodulation noise, and enhances energy efficiency by allowing operation near resonance frequencies, ensuring that any selected heating power is achievable with minimal noise and consistent power delivery.
Implementation Method 1
A heating unit is intended to mean, in particular, a unit that is intended to at least partially convert electrical energy into heat and thus in particular to heat a food item to be cooked. In particular, the heating unit comprises a radiant heater, a resistance heater and/or preferably an induction heater, which is intended to convert electrical energy into heat indirectly via induced eddy currents.
Implementation Method 2
an induction heater, which is intended to convert electrical energy into heat indirectly via induced eddy currents
Data Source
Figure 1~2
Figure 3a~3c
Figure 4a~4c
AI summary
The invention relates to a cooking appliance with at least two heating frequency units (10, 12) and at least one control unit (14) designed to adjust the respective average output power (P0A, P0B) of the heating frequency units (10, 12) while largely avoiding intermodulation noise. To provide a cooking appliance of this type with the most continuous power output possible, it is proposed that the control unit (14) be designed to change a non-zero frequency (f2) of one of the heating frequency units (12) to a non-zero value (f3) while maintaining operation of the other heating frequency unit (10).