Parallel Switching Elements for Induction Heating Resonance Frequency
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Solution Overview
Problem
Existing induction heating apparatuses are limited in increasing the resonance frequency of their working coils due to the physical properties of switching elements, which restricts the ability to make the coils slim and lightweight, and the use of wide-band-gap semiconductor elements increases manufacturing costs while compromising reliability.
Innovation Solution
The induction heating apparatus employs a parallel configuration of two switching elements with synchronized switching signals and a controller to adjust the rising edge timing of these signals, effectively doubling the driving frequency of the working coil without increasing manufacturing costs, thereby enhancing the resonance frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the resonance frequency of the working coil is increased to make the coil slim and lightweight, then the switching frequency of the switching element must be increased, but the physical properties of the switching element prevent the switching frequency from reaching the required level
Solution Approach 1:
The patent divides the switching function into two separate switching elements (first switching element and second switching element) that operate in parallel. Each switching element handles half of the switching cycles, allowing the system to achieve a higher effective switching frequency (twice the individual element frequency) while each element operates at a reliable, lower frequency within its physical capabilities.
2Speed
If a wide-band-gap semiconductor element is used to achieve high switching frequency, then the resonance frequency can be increased, but the manufacturing cost increases and reliability decreases
Solution Approach 1:
The patent uses two ordinary switching elements that replicate the same switching function, rather than using a single specialized wide-band-gap element. This approach achieves the required high effective switching frequency through parallel operation of standard, cost-effective components, avoiding the need for expensive specialized materials while maintaining system reliability.
3Productivity
If a single switching element operates at high frequency, then the resonance frequency increases, but the switching element cannot maintain reliable operation at the required frequency
Solution Approach 1:
The patent segments the high-frequency switching task across two parallel switching elements, where each element operates at a lower, more reliable frequency. The controller coordinates their operation so that they alternate switching cycles, effectively doubling the system's output frequency while each individual element remains within its reliable operating range.
Solution Approach 2:
The patent combines the output of two parallel switching circuits to achieve the desired high-frequency performance. By merging the switching actions of two reliable low-frequency elements operating in parallel with coordinated control, the system achieves the equivalent performance of a single high-frequency element without the reliability penalties.
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 allows for a higher resonance frequency of the working coil, making it slim and lightweight while ensuring reliable operation without additional manufacturing costs, thus improving the efficiency and performance of the induction heating apparatus.
Implementation Method 1
a rectifying circuit rectifying an AC voltage that is supplied from a power source
Implementation Method 2
a smoothing circuit connecting to the rectifying circuit and smoothing a voltage that is output from the rectifying circuit
Implementation Method 3
As electric energy is supplied to a working coil included in an induction heating apparatus, a magnetic field is formed around the working coil
Implementation Method 4
The magnetic field generates eddy current in a container that is placed on the working coil, to heat the container
Implementation Method 5
The magnetic field generates eddy current in a container that is placed on the working coil, to heat the container
Data Source
AI summary
An induction heating apparatus of one embodiment may comprise a rectifying circuit rectifying an AC voltage supplied from a power source, a smoothing circuit connecting to the rectifying circuit and smoothing a voltage output from the rectifying circuit, a first switching element having a first terminal that connects to a working coil, and a second terminal that connects to the smoothing circuit, a second switching element connecting to the first switching element in parallel, a driving circuit supplying a first switching signal to the first switching element and a second switching signal to the second switching element, and a controller outputting a first control signal corresponding to the first switching signal, and a second control signal corresponding to the second switching signal.