Cooking Appliance Frequency Control for Intermodulation Noise
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Solution Overview
Problem
Existing cooking appliances struggle to provide a flexible and easy-to-implement setting for average output power while minimizing intermodulation noise, especially when operating multiple heating frequency units simultaneously.
Innovation Solution
A cooking appliance device with at least two heating frequency units, where one unit operates continuously at a fixed frequency and the other unit is operated in alternating time intervals with a frequency differing by at least 15 kHz, allowing for flexible adjustment of average output power and easy implementation through control signals, while minimizing intermodulation noise by adapting duty cycles and frequencies to match target powers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple heating frequency units are operated simultaneously to provide flexible output power settings, then adaptability is improved, but intermodulation noise increases
Solution Approach 1:
The patent applies periodic action by operating the second heating frequency unit in alternating first and second time intervals. During the first time interval, the second heating frequency unit operates at a frequency different from the first frequency unit. During the second time interval, the second heating frequency unit is switched off. This periodic operation allows flexible average output power control while minimizing intermodulation noise by reducing simultaneous operation of multiple frequency units.
2Object-generated harmful factors
If the second heating frequency unit is switched off in alternating time intervals to reduce intermodulation noise, then harmful factors are reduced, but continuous heating capability is worsened
Solution Approach 1:
The patent applies parameter changes by varying the frequency of the second heating frequency unit during the first time interval. The frequency is selected to be different from the first frequency unit by at least 15 kHz, preferably at least 16 kHz, and particularly advantageously by at least 17 kHz. This frequency parameter change allows the system to achieve flexible average output power settings while minimizing intermodulation noise. The duty cycle of the periodic operation is adjusted to maintain the required average power output.
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
Enables flexible and precise adjustment of average output powers across multiple heating frequency units, effectively reducing intermodulation noise and adhering to legal standards, enhancing operating comfort and scalability.
Implementation Method 1
The invention is based on a cooking appliance device with at least one first and at least one second heating frequency unit
Implementation Method 2
a 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
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
The invention relates to a cooking appliance with at least one first and at least one second heating frequency unit (10a, 12a; 10b, 12b) and with at least one control unit (14a; 14b) designed to operate the first heating frequency unit (10a; 10b) continuously at a fixed first frequency (f1) and to operate the second heating frequency unit (12a; 12b) in at least one first time interval (TA) and to switch it off in at least one second time interval (TB). To provide a cooking appliance of this type that allows for advantageously flexible and easily implementable adjustment of an average output power, it is proposed that the control unit (14a; 14b) be designed to operate the second heating frequency unit (12a; 12b) in the first time interval (TA) at at least one frequency (f2) that differs from the first frequency (f1) by at least 15 kHz.