Induction Cooker Control Method for Noise Reduction
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Solution Overview
Problem
Induction heating cookers generate undesirable noise due to high-frequency expansions and contractions at the base of the pot, which affects user satisfaction and requires expensive hardware changes in existing solutions.
Innovation Solution
A control method using two separate clock generators, a modulation signal generator, and a comparator to minimize frequency shifts and irregularities by comparing counter values and providing feedback to the power switch, reducing noise without additional hardware components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high current (400-600 A) is passed through the induction coil to achieve rapid heating, then heating efficiency is improved, but noise generation increases due to high-frequency expansions and contractions at the base of the pot
Solution Approach 1:
The patent applies periodic action by using pulse width modulation (PWM) to periodically switch the power delivery to the induction coil. The microprocessor controls the switching element to deliver power in controlled pulses rather than continuous high current, reducing the intensity of thermal expansion-contraction cycles that generate noise while maintaining heating efficiency through high-frequency periodic operation
Solution Approach 2:
The patent changes operational parameters by dynamically adjusting the fill factor and frequency of the PWM signal. The microprocessor monitors and adjusts these parameters to optimize the balance between heating performance and noise reduction, modifying the electrical characteristics of the induction coil operation to minimize acoustic emissions
2Object-generated harmful factors
If the fill factor and frequency of the PWM signal are adjusted to reduce noise, then noise level decreases, but heating performance may be affected
Solution Approach 1:
The patent implements feedback control where the microprocessor monitors the actual heating performance and noise levels, then adjusts the PWM fill factor and frequency accordingly. This closed-loop control ensures that noise reduction measures do not compromise heating performance, as the system continuously optimizes the balance between these two parameters based on real-time conditions
3Object-generated harmful factors
If expensive hardware changes are implemented to reduce noise, then noise reduction effectiveness is improved, but system cost increases
Solution Approach 1:
The patent replaces potential mechanical or hardware-based noise reduction solutions with a software/control-based approach. The microprocessor-controlled PWM modulation provides noise reduction through electrical control rather than physical modifications to the induction coil or pot structure, avoiding expensive hardware changes while achieving effective noise mitigation
Solution Approach 2:
The system uses its existing control infrastructure (microprocessor and PWM circuitry) to perform noise reduction functions. The same control elements that regulate heating performance are leveraged to simultaneously manage noise levels, eliminating the need for additional dedicated hardware components and reducing overall system cost
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
Significantly reduces unwanted noise from induction cookers by stabilizing frequency and eliminating irregular movements, improving user satisfaction and system performance at a lower cost.
Implementation Method 1
by means of the magnetic field generated by the current passing through the induction coil, voltage is inducted at the base of the pot
Implementation Method 2
current is passed through the base of the pot, thus the Eddy current begins to flow on the surface of the heated metal and heating is provided
Implementation Method 3
a high temperature difference occurs between the heated area and the regions farther away, and minor expansions and contractions at high frequency are observed with the current flowing rapidly
Implementation Method 4
pushing and pulling movements occur due to the magnetic flux generated by the current passing through the base
Data Source
AI summary
The present invention relates to a control method which is suitable to be used in induction heating cookers comprising a first clock generator which works at high speed and which determines the main clock frequency; a second clock generator which works in real time; at least one amplifier module which enables the system to drive the signal from the first clock generator at higher frequencies; at least one modulation signal generator comprising at least one counter which separately counts the periods of the signal from the amplifier module and the signal from the second clock generator and a comparator which compares the counter values; at least one power switch which receives the signals passing through the modulation signal generator and which enables power switching; and a control unit which controls the clock generator, the amplifier module and the modulation signal generator, the control method being executed by the control unit.