Air-Core Inductance Adjusting Device for High Current
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Solution Overview
Problem
Existing inductance adjustment techniques face challenges such as increased core loss, complex device structures, and inaccurate frequency control due to excessive repulsive and attractive forces when handling large currents, particularly in induction heating and non-contact power feeding applications.
Innovation Solution
An inductance adjusting device comprising two coils with specific circumferential and connecting portions, arranged in a parallel state with an interval, where one coil rotates 180° to adjust inductance, minimizing core usage and structural complexity, and maintaining a balanced force distribution to enable precise frequency control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a magnetic core is inserted in the solenoid coil to adjust inductance, then the inductance can be adjusted by changing occupancy ratio, but the core loss increases and heating efficiency deteriorates when large current is applied
Solution Approach 1:
The patent removes the magnetic core from the solenoid coil structure entirely. Instead of using a magnetic core to adjust inductance through occupancy ratio changes, the invention uses air-core coils where inductance is adjusted by changing the number of effective turns through selective connection, thereby eliminating core loss and hysteresis heating issues
Solution Approach 2:
The patent replaces the mechanical method of adjusting inductance by physically moving or inserting a magnetic core with an electrical method of selectively connecting coil sections. This substitution eliminates the need for magnetic materials and their associated losses while achieving the same inductance adjustment function
2Measurement precision
If capacitor for fine adjustment is connected to or disconnected from the circuit to adjust electrostatic capacitance, then the target frequency can be achieved, but additional components are required and device cost increases
Solution Approach 1:
The patent makes the existing solenoid coil serve multiple functions: it acts as both the main inductance element and the fine-adjustment element. By dividing the coil into sections with different turn counts and selectively connecting them, the same coil structure provides both coarse and fine inductance adjustment, eliminating the need for separate capacitor banks
Solution Approach 2:
The patent combines the functions of main inductance provision and fine adjustment into a single coil structure. The solenoid coil is divided into multiple sections that can be connected in series or parallel, allowing the same component to provide both the primary inductance value and fine-tuning capability
3Ease of operation
If the solenoid coil is extended and contracted to adjust inductance, then inductance can be varied, but the device size increases and support structure becomes complicated
Solution Approach 1:
The patent divides the solenoid coil into multiple discrete sections with specific turn counts. Instead of continuously extending or contracting the coil, the invention segments the coil windings into manageable sections that can be independently connected, simplifying the adjustment mechanism and support structure
4Ease of operation
If two coils are rotated about ends as shaft to change rotation angle and adjust inductance, then inductance can be adjusted, but excessive repulsive and attractive forces occur when large current is applied
Solution Approach 1:
The patent removes the rotating coil mechanism with shaft-based adjustment. Instead of using two coils that rotate relative to each other creating magnetic forces, the invention uses a single stationary solenoid coil where sections are selectively connected electrically, eliminating the mechanical rotation and associated electromagnetic forces
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 accurate and efficient adjustment of inductance with a simple and compact structure, reducing core loss and enhancing heating efficiency while maintaining precise control over frequency, even with large currents.
Implementation Method 1
a first coil (1) including a first circumferential portion (1a), a second circumferential portion (1b), and a first connecting portion (1c); and a second coil (3) including a third circumferential portion (3a), a fourth circumferential portion (3b), and a second connecting portion (3c)
Implementation Method 2
at least one of the first coil (1) and the second coil (3) rotates about a shaft of the first coil (1) and the second coil (3) as a rotation shaft
Data Source
AI summary
Coil surfaces of a first coil (1) and a second coil (3) are parallel in a state of having an interval therebetween. When the first coil (1) rotates, a combined inductance by the first coil (1) and the second coil (3) changes.