Induction Hob Frequency Modulation for EMC and Noise Control
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Solution Overview
Problem
Existing cooking appliance devices, particularly induction hobs, face challenges in complying with EMC standards and achieving precise control over heating power, leading to increased complexity and potential noise issues.
Innovation Solution
A cooking appliance device with a control and/or regulating unit that varies the heating current frequency in periodic continuous heating operation states to maintain constant actual and/or complex conductance, thereby achieving precise heating power control and compliance with EMC standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex control schemes are used to control inductors for heating cookware, then heating precision is improved, but device complexity increases and EMC compliance becomes difficult to achieve
Solution Approach 1:
The patent applies periodic action by switching between different heating current frequencies in a periodic manner. The control unit alternates between a first frequency and a second frequency during different time intervals within an operating period, creating a periodic frequency variation pattern that simplifies the overall control scheme while maintaining heating precision and EMC compliance
Solution Approach 2:
The patent changes the frequency parameter of the heating current to resolve the contradiction. By varying the frequency between at least two different values (first frequency and second frequency) during different time intervals, the system achieves precise heating power control without requiring complex control schemes, as the frequency modulation itself provides the necessary control flexibility
2Reliability
If frequency spread techniques are used to comply with EMC standards, then EMC compliance is improved, but noise generation increases
Solution Approach 1:
The patent uses periodic action to alternates between different frequencies in a controlled manner. By switching between a first frequency and a second frequency during different time intervals, the system achieves EMC compliance through frequency variation while avoiding continuous frequency spreading that would generate noise. The periodic nature of the switching allows for controlled frequency variation without excessive noise generation
3Productivity
If high heating power is applied to achieve desired heating speed, then productivity is improved, but power outage risk increases
Solution Approach 1:
The patent applies periodic action by switching between different frequencies to control the heating power delivery. During different time intervals within an operating period, the system uses a first frequency for higher power delivery to maintain productivity, and a second frequency to reduce power and avoid exceeding maximum power requirements, thereby preventing power outages while maintaining overall heating efficiency
Solution Approach 2:
The patent makes the heating current frequency dynamic by switching between at least two different frequencies (first frequency and second frequency) based on the operational requirements. This dynamic frequency adjustment allows the system to optimize between heating speed and power safety margins, preventing power outages while maintaining high productivity through intelligent frequency modulation rather than continuous high-power operation
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
The solution enables a cost-efficient and energy-saving cooking appliance device that operates with low noise and precise heating control, while avoiding the need for EMC filters and minimizing power outages.
Implementation Method 1
at least one induction target (32, 32', 32'', 32''') for heating, in particular for inductive heating, of items of cookware (14, 14', 14'', 14''')
Implementation Method 2
operate the induction target (32, 32', 32'', 32''') in at least one switched-on interval (40, 40') of the operating period (42) with a heating power
Data Source
AI summary
A cooking appliance device includes a control and/or regulating unit which is provided such that in a periodic continuous heating operation state, which is allocated at least one operating period, an induction target is repetitively controlled, supplied with energy, and operated in a switched-on interval of the operating period with a heating power, and that in the continuous heating operating state a heating current frequency for the induction target in the switched-on interval of the operating period is varied.