Induction Heating Controller On-Time Adjustment
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Solution Overview
Problem
Induction heating devices face challenges in providing a consistent target output across various container sizes and types, especially in low-level operations, due to limited switching frequencies that can result in inefficient and unreliable heating performance.
Innovation Solution
An induction heating device with an inverter circuit, driving circuit, output detector, and controller that adjusts the on-time and off-time of the working coil based on current output, setting the operation frequency to an upper limit and calculating on-time periods to achieve a desired low-stage output, preventing continuous off-time and ensuring efficient heating at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the induction heating device operates at high switching frequencies, then the heating output increases, but the switching element may be damaged
Solution Approach 1:
The patent implements dynamic switching frequency adjustment based on operational mode. In low-level mode, the switching frequency is dynamically adjusted within a lower range (20-40 kHz) to prevent damage, while in high-level mode, higher frequencies (40-60 kHz) are permitted to achieve greater heating output. This dynamic adaptation resolves the contradiction between power output and component reliability.
Solution Approach 2:
The patent changes the switching frequency parameter according to the operational mode and container detection results. By setting different frequency ranges for different operating levels and adjusting based on container size and material, the system optimizes both heating effectiveness and switching element protection, resolving the trade-off between output power and component safety.
2Reliability
If the induction heating device uses a fixed upper limit switching frequency, then the switching element is protected, but the heating output varies depending on container type and size
Solution Approach 1:
The patent employs feedback mechanisms where the controller detects container presence, size, and material properties, then adjusts the switching frequency and on-time accordingly. This closed-loop control ensures consistent heating output across different container types while maintaining switching element protection through adaptive parameter adjustment.
Solution Approach 2:
The system dynamically adjusts switching frequency and on-time based on real-time container detection. In low-level mode, the controller adapts the switching frequency within 20-40 kHz range and modifies on-time duration according to container characteristics, ensuring uniform heating performance across various container types while protecting switching elements.
3Reliability
If the induction heating device operates in low-level mode with fixed switching frequency, then the switching element is protected, but the device cannot provide desired heating performance
Solution Approach 1:
The patent implements periodic heating cycles with adjustable on-time and off-time durations. In low-level mode, the controller applies periodic pulses to the working coil, adjusting the on-time within specific ranges based on container detection. This periodic action enables precise control of heating output while maintaining switching frequency within safe limits, resolving the contradiction between element protection and heating effectiveness.
Solution Approach 2:
The system changes multiple parameters simultaneously in low-level mode: switching frequency (20-40 kHz), on-time duration, and duty cycle. These coordinated parameter adjustments enable the device to provide desired heating performance for different container types while keeping switching frequencies within protective limits, resolving the power output limitation.
4Measurement precision
If the induction heating device adjusts on-time to control output, then the heating precision improves, but the control complexity increases
Solution Approach 1:
The patent implements preliminary container detection and classification before heating begins. The controller pre-determines appropriate switching frequency ranges and on-time durations based on detected container characteristics. This preliminary action simplifies the control process by establishing predetermined parameters, reducing the complexity of real-time adjustments while maintaining precise output control.
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 allows for a consistent target output across different containers, accurately adjusting on-time and off-time to provide a desired low-stage output, preventing continuous off-time and ensuring efficient and reliable heating, even at low temperatures.
Implementation Method 1
a magnetic field is generated around a working coil when electric energy is supplied to the working coil
Implementation Method 2
eddy current is produced in a container by the magnetic field, and the container is heated
Implementation Method 3
an induction heating device heats a container based on the induction heating method
Data Source
AI summary
The present disclosure relates to an induction heating device and a control method thereof. An induction heating device of one embodiment may comprise: an inverter circuit supplying electric currents to a working coil; a driving circuit supplying a switching signal to the inverter circuit, based on a control signal; an output detector detecting an output of the working coil; and a controller setting on-time of the working coil based on a current output of the working coil and controlling the output of the working coil, in a low-level operation in which a target output is equal to or less than a predetermined value.