Induction Cooktop Frequency Modulation for Lower EMC Noise
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Solution Overview
Problem
Existing induction cooktops require high-performance ASICs for computationally intensive frequency modulation, leading to increased costs and electromagnetic interference, which affects user comfort and compliance with EMC standards.
Innovation Solution
Modulating the switching frequency within a modulation period that is an integer multiple of half a mains AC voltage period using frequency modulation, reducing computational effort and interference, and allowing for the use of simpler and more cost-effective circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high-performance ASICs are used for frequency modulation, then frequency modulation can be performed, but costs increase and electromagnetic interference worsens
Solution Approach 1:
The patent changes the modulation period parameter from the conventional maximum of half a mains AC voltage period to an integer multiple of half a mains AC voltage period (e.g., 10ms, 20ms, 40ms). This parameter change reduces the switching frequency modulation rate, thereby reducing electromagnetic interference while maintaining effective frequency modulation capability without requiring high-performance ASICs
Solution Approach 2:
The patent implements periodic frequency modulation where the modulation period is synchronized with the mains AC voltage period. By setting the modulation period to an integer multiple of half the mains AC voltage period, the frequency modulation is performed periodically in sync with the power grid, which reduces electromagnetic interference and allows for simpler circuit implementation
2Device complexity
If modulation period is extended to integer multiple of half mains AC voltage period, then computational effort is reduced, but frequency modulation performance may be affected
Solution Approach 1:
The patent extends the modulation period parameter from the conventional short duration (maximum half a mains AC voltage period) to a longer duration that is an integer multiple of half the mains AC voltage period. This parameter extension reduces the rate of frequency changes, thereby reducing computational effort while maintaining effective frequency modulation through synchronized periodic action with the mains voltage
Solution Approach 2:
The patent employs periodic frequency modulation where the control unit modulates the switching frequency at intervals that are integer multiples of half the mains AC voltage period. This periodic action synchronized with the power grid ensures that frequency modulation remains effective for reducing electromagnetic interference while requiring less computational processing
3Object-generated harmful factors
If switching frequency is modulated frequently, then electromagnetic interference is reduced, but user comfort deteriorates due to acoustic stress
Solution Approach 1:
The patent changes the modulation frequency parameter by extending the modulation period to an integer multiple of half the mains AC voltage period. This reduces the rate at which the switching frequency is modulated, thereby reducing acoustic stress and improving user comfort while still maintaining effective electromagnetic interference reduction through synchronized periodic modulation
Solution Approach 2:
The patent implements periodic frequency modulation synchronized with the mains AC voltage, where the modulation period is an integer multiple of half the mains voltage period. This synchronized periodic action reduces high-frequency switching variations that cause acoustic stress, thereby improving user comfort while maintaining electromagnetic interference reduction through the periodic nature of the modulation
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 enhances user comfort by minimizing acoustic stress and electromagnetic interference, reduces material costs, and ensures compliance with EMC standards, providing efficient and cost-effective induction cooktop operation.
Implementation Method 1
the control unit modulates the switching frequency within a modulation period, which corresponds to an integer multiple of half a period of a mains AC voltage, by means of at least one frequency modulation
Implementation Method 2
control unit which is designed to repeatedly control and supply energy to at least one induction target at a switching frequency
Data Source
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AI summary
The invention relates to a domestic appliance device (10a-e), in particular a cooking appliance device, comprising at least one control unit (12a-e) which is provided to control at least one induction target (14a-e) repetitively with a switching frequency (16a-e) and to supply same with power. According to the invention, in order to provide a generic device with improved efficiency, the control unit (12a-e), in an operating state, modulates the switching frequency (16a-e) within a modulation period (18a-e) which corresponds to an integer multiple of a half period duration (20a-e) of a mains AC voltage (22a-e), by means of at least one frequency modulation.