Parallel Heating Coils with Shared Switching Devices
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Solution Overview
Problem
Conventional induction heat cooking apparatuses require a large number of switching devices to operate multiple heating coils, leading to increased product volume and cost, especially when the number of heating coils exceeds two.
Innovation Solution
The apparatus employs a minimum number of switching devices by controlling multiple heating coils using a controller that alternates the switching states of the devices between closed and open states during different resonant periods, allowing for efficient operation with fewer devices, such as using N+1 switching devices to drive N heating coils in parallel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple inverters with separate switching devices are used to operate multiple heating coils, then each heating coil can be independently controlled, but the number of switching devices increases, leading to increased product volume and cost
Solution Approach 1:
Multiple heating coils are connected in parallel to a single inverter circuit, sharing common switching devices (Q1, Q2, Q3, Q4) and resonant capacitors. The coils are controlled by adjusting individual duty cycles through the controller, enabling independent control while reducing the total number of switching devices compared to separate inverter configurations.
Solution Approach 2:
A single inverter circuit with shared switching devices serves multiple heating coils simultaneously. The switching devices and resonant capacitors perform multiple functions by being shared across different heating coils, reducing component count while maintaining the ability to independently control each coil's heating output.
2Adaptability or versatility
If the number of heating coils is increased to three or more, then cooking versatility is improved, but a plurality of switching devices are required according to the number of heating coils, increasing product volume and cost
Solution Approach 1:
Multiple heating coils share a common inverter circuit with shared switching devices and resonant capacitors. This merging of components allows three or more heating coils to be operated with a single inverter circuit, significantly reducing the overall product volume compared to having separate inverter circuits for each coil.
Solution Approach 2:
The switching devices operate in periodic cycles with controlled duty cycles to sequentially or simultaneously drive multiple heating coils. This periodic switching enables efficient use of shared components while maintaining independent control capability for each heating coil, optimizing space utilization.
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 reduces the size and production cost of the induction heat cooking apparatus while maintaining effective operation of multiple heating coils, allowing for efficient energy transfer and cooking performance.
Implementation Method 1
an induction heat cooking apparatus performing a cooking function using a method in which a high-frequency current causes to flow through a working coil or a heating coil, and an eddy current flows when a strong line of magnetic force that is accordingly generated passes through a cooking container, and thus the cooking container itself is heated
Implementation Method 2
an eddy current flows when a strong line of magnetic force that is accordingly generated passes through a cooking container, and thus the cooking container itself is heated
Implementation Method 3
a first resonant capacitor 161 connected to one end of the first heating coil 141, a second resonant capacitor 162 connected to the other end of the first heating coil 141, a third resonant capacitor 163 connected to one end of the second heating coil 142, and a fourth resonant capacitor 164 connected to the other end of the second heating coil 142
Data Source
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AI summary
Provided is an induction heat cooking apparatus including a rectifier configured to rectify an input voltage and to output a DC voltage; a plurality of switching devices configured to switch the DC voltage output through the rectifier; a plurality of heating coils configured to heat a cooking container according to control of the plurality of switching devices; and a controller configured to control the plurality switching devices to simultaneously drive at least two or more heating coils connected in parallel with each other among the plurality of heating coils.