Induction Heating Inverter Control for Quiet Container Detection
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Solution Overview
Problem
Induction heating devices generate driving noise during container detection, causing user inconvenience and potential perception of device failure.
Innovation Solution
An induction heating apparatus with a controller that adjusts the duty ratio and frequency of switching signals to minimize noise during container detection by gradually changing these parameters, using a current and voltage sensor to determine the presence of a container.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the induction heating device detects a container using resonance current measurement, then container detection capability is improved, but driving noise increases due to instant increase in peak-to-peak current value
Solution Approach 1:
The patent applies dynamics by making the duty ratio of the switching signal variable rather than fixed. The controller dynamically adjusts the duty ratio based on the detected resonance current value, increasing it when container is detected and decreasing it when no container is present. This dynamic adjustment optimizes both detection accuracy and noise reduction, resolving the contradiction between reliable detection and noise generation.
Solution Approach 2:
The patent changes the parameter of duty ratio in response to detection results. When a container is detected through resonance current measurement, the controller increases the duty ratio to enhance heating efficiency. When no container is detected, it decreases the duty ratio to minimize noise and power consumption. This parameter change strategy allows the system to adapt to different operational states, resolving the contradiction between detection reliability and noise control.
2Duration of action of stationary object
If continuous current is supplied to the working coil without a container, then the induction heating apparatus operates continuously, but electric power is wasted and overheat occurs
Solution Approach 1:
The patent implements feedback control by continuously monitoring the resonance current value and using it to control the duty ratio of the switching signal. The controller adjusts the duty ratio based on the detected resonance current, creating a closed-loop control system. This feedback mechanism ensures that power is only consumed when a container is present and heating is needed, eliminating continuous power waste and preventing overheat conditions.
Solution Approach 2:
The patent uses periodic switching signals with variable duty ratios to control the working coil. Instead of continuous current supply, the system applies periodic pulses whose duty ratio is modulated based on container detection. This periodic action with adaptive duty cycle ensures energy is delivered only when necessary, resolving the contradiction between continuous operation capability and energy efficiency.
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
Minimizes driving noise during container detection, enhancing user satisfaction and reducing the likelihood of perceived device malfunction.
Implementation Method 1
induction heating involves generating eddy current in a container made of metal with a magnetic field that is generated around a coil when high-frequency power having predetermined magnitude is supplied to the coil
Implementation Method 2
induction heating involves generating eddy current in a container made of metal with a magnetic field that is generated around a coil
Implementation Method 3
when current is supplied to the working coil through an inverter circuit... based on resonance current generated in the working coil
Data Source
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AI summary
An induction heating apparatus according to one embodiment comprises a working coil disposed in a position corresponding to a heating zone, an inverter circuit that comprises a plurality of switching elements and supplies current to the working coil, a driving circuit that supplies a switching signal to each of the switching elements included in the inverter circuit, a current sensor that measures a resonance current value, magnitude of resonance current flowing in the working coil, and a controller that supplies a control signal for adjusting a duty ratio and a frequency of the switching signal to the driving circuit, to drive the working coil.