Induction Hob Gate Driving Signal Pulse Control
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Solution Overview
Problem
Induction cooking hobs experience acoustic noise due to frequency jittering, which existing methods have not effectively addressed with low complexity solutions.
Innovation Solution
A method controlling the cooking zone by varying the activation pulse length Ton based on requested power while maintaining a constant deactivation pulse length Toff, determined by the resistance and inductance of the induction coil, to reduce frequency jittering and acoustic noise without requiring additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pulse duration of the enabling signal is reduced to reduce acoustic noise, then the acoustic noise is reduced, but the power delivery efficiency is compromised
Solution Approach 1:
The patent applies dynamics by making the deactivation pulse length Toff variable rather than fixed. The control unit adjusts Toff based on feedback from the cooking process, allowing the system to optimize both noise reduction and power delivery dynamically. This resolves the contradiction by enabling adaptive control that balances acoustic noise reduction with effective power transfer to the cookware.
Solution Approach 2:
The patent changes the parameter of pulse duration from a simple reduction approach to a sophisticated variable parameter control. By adjusting both the activation pulse length Ton and deactivation pulse length Toff based on process conditions, the system achieves optimal performance. This resolves the contradiction by transforming static parameter control into dynamic parameter optimization.
2Power
If the deactivation pulse length Toff is made variable to optimize power delivery, then the power delivery efficiency is improved, but the system complexity increases
Solution Approach 1:
The patent implements feedback control where the control unit monitors the cooking process and adjusts the deactivation pulse length Toff accordingly. This feedback mechanism enables the system to optimize power delivery without requiring complex manual intervention or additional hardware. The feedback loop automatically adapts the control parameters to maintain optimal performance while managing system complexity.
Solution Approach 2:
The system performs self-adjustment of the deactivation pulse length Toff based on inherent process feedback. The control unit automatically optimizes the pulse parameters without external intervention, allowing the system to self-regulate power delivery efficiency. This self-service approach reduces the need for complex external control mechanisms while maintaining optimized performance.
3Device complexity
If a series of constant activation pulse length Ton is activated to determine the optimal deactivation pulse length Toff, then the optimal Toff is determined with low complexity, but the control process time increases
Solution Approach 1:
The patent applies preliminary action by performing a calibration phase where a series of constant activation pulse length Ton is activated to determine the optimal deactivation pulse length Toff before normal operation begins. This preliminary determination of Toff values is stored and reused during subsequent cooking operations, avoiding repeated time-consuming measurements. This resolves the contradiction by front-loading the complexity into an initial setup phase rather than continuous 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
This approach effectively reduces acoustic noise and determines the optimal deactivation pulse length, ensuring efficient power delivery and reduced electrical noise sensitivity, while maintaining hardware simplicity.
Implementation Method 1
at least one induction coil (16) which is supplied with an alternating current
Implementation Method 2
induction heating cooker
Implementation Method 3
heating process
Data Source
AI summary
The present invention relates to a method for controlling a cooking zone (16) of an induction cooking hob, wherein said cooking zone (16) comprises at least one induction coil (16) and is supplied by a generator (14) including a power switch. The method is performed by controlling the power switch by a gate driving signal (18) including a deactivation pulse length (Toff) and an activation pulse length (Ton). A switching period (T) of the gate driving signal (18) is given by the sum of the activation pulse length (Ton) and deactivation pulse length (Toff). A driving frequency (f) of the power switch is the reciprocal value of said switching period (T). The deactivation pulse length (Toff) depends on the resistance (28) and the inductance (30) of the induction coil (16). The activation pulse length (Ton) is varied according to a requested power for the cooking zone (16). A series of constant activation pulse length (Ton) is activated in order to determine the optimal deactivation pulse length (Toff).