Inductive Heating Control via Frequency-Tuned LC Resonators
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Solution Overview
Problem
Existing aerosol-generating devices using inductively heating aerosol-forming substrates face challenges in efficiently and reliably controlling multiple induction coils to prevent power overload and undesired heating, requiring complex control of transistor switches and precise timing.
Innovation Solution
The aerosol-generating device employs a control circuit with multiple induction coils, each part of a distinct LC resonator circuit with different resonance frequencies, inductively coupled to a common oscillator coil operating at specific frequencies, allowing for selective activation of coils to prevent current induction in inactive coils and reducing complexity by using a single transistor switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple transistor switches are used to control each induction coil separately, then selective heating of different sections can be achieved, but the control complexity increases and reliability decreases due to precise timing requirements and power overload risks
Solution Approach 1:
The patent combines multiple induction coils into a single LC resonator circuit that operates at multiple frequencies. Instead of using separate transistor switches for each coil, the invention uses a single resonant circuit with a variable frequency source that can selectively excite different coils by tuning to their respective resonance frequencies, thereby reducing control complexity while maintaining selective heating capability
Solution Approach 2:
The invention changes the operating frequency parameter of the LC resonator circuit to selectively activate different induction coils. Each coil is designed to resonate at a specific frequency, and by varying the oscillator frequency, the system can selectively heat different sections without requiring complex switching control, thus improving reliability and reducing device complexity
2Reliability
If multiple transistor switches with precise timing control are used, then power overload can be prevented, but the device complexity and difficulty of control increase
Solution Approach 1:
The patent uses frequency tuning as the primary control mechanism instead of time-based switching. By changing the oscillator frequency to match the resonance frequency of a specific coil, the system naturally directs power to that coil while others remain inactive. This frequency-based selection inherently prevents power overload without requiring complex timing control or multiple transistor switches, thereby improving reliability while reducing control complexity
3Manufacturing precision
If induction coils are operated independently with separate control circuits, then selective heating precision is improved, but the overall device complexity and manufacturing cost increase
Solution Approach 1:
The patent implements a universal LC resonator circuit that can serve multiple induction coils through frequency tuning. A single resonant circuit with variable frequency capability can selectively excite any of the induction coils by matching their respective resonance frequencies. This multi-functional approach achieves precise selective heating while using only one control circuit, thereby reducing manufacturing complexity and cost compared to having separate control circuits for each coil
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 solution effectively decouples inactive coils from active coils, preventing undesired heating and reducing complexity, thereby enhancing the reliability and efficiency of the aerosol generation process while maintaining precise control over heating.
Implementation Method 1
The first induction coil is arranged and configured to generate an alternating magnetic field within a first section of the cavity. The second induction coil is arranged and configured to generate an alternating magnetic field within a second section of the cavity.
Implementation Method 2
Aerosol-generating systems based on inductively heating an aerosol-forming substrate that is capable to form an inhalable aerosol
Implementation Method 3
The first LC resonator has a first resonance frequency and the second LC resonator circuit has a second resonance frequency that is different from the first resonance frequency
Implementation Method 4
The common oscillator coil is inductively coupled to the first induction coil and to the second induction coil such that an alternating magnetic field is generated within the first section when the frequency of the oscillator field is close to or at the first resonance frequency
Data Source
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AI summary
The present invention relates to an aerosol-generating device for generating an aerosol by inductively heating an aerosol-forming substrate. The invention further relates to an aerosol-generating system comprising such a device and an aerosol-generating article, wherein the article comprises the aerosol-forming substrate to be heated. The device comprises a first LC resonator circuit and a second LC resonator circuit, wherein the first LC resonator circuit has a first resonance frequency and the second LC resonator circuit has a second resonance frequency that is different from the first resonance frequency. The control circuit further comprises a driving oscillator circuit comprising an oscillator coil inductively coupled to the induction coils for selectively generating an alternating magnetic oscillator field either at the first resonance frequency or at the second resonance frequency, such that an alternating magnetic field is selectively generated to selectively heat different sections of a susceptor or different susceptors in different sections of the device. The invention further relates to an aerosol-generating system comprising such a device and an aerosol-generating article, wherein the article comprises the aerosol-forming substrate to be heated.