Sawtooth Planar Inductor Core for Tunable Air Gap Assembly
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Solution Overview
Problem
Conventional planar inductor cores require tight manufacturing tolerances for concentric gaps, which are difficult to achieve with standard manufacturing processes, leading to high rejection rates due to sintering size variations and machining limitations.
Innovation Solution
The use of sawtooth-configured inner and outer cores allows for tunable inductance by adjusting the air gap during assembly, eliminating the need for expensive CNC machining and enabling standard ferrite core manufacturing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional concentric gap configuration is used, then leakage inductance function is achieved, but manufacturing precision requirement becomes excessively tight (+/-0.05mm)
Solution Approach 1:
The patent replaces the symmetric concentric circular gap with an asymmetric rectangular gap configuration. The inner core has width W1 and the outer core has width W2, creating an asymmetric rectangular air gap that is easier to manufacture with standard tolerances while maintaining the leakage inductance function.
Solution Approach 2:
Instead of trying to achieve tight tolerances on the gap width through expensive CNC machining, the patent inverts the approach by designing a gap configuration that is inherently more tolerant to manufacturing variations, using standard ferrite core sizes and simple machining or assembly processes.
2Manufacturing precision
If expensive CNC machining is used to achieve tight tolerances, then manufacturing precision improves, but production cost increases significantly
Solution Approach 1:
The patent accepts that individual cores may have slight manufacturing variations but designs the rectangular gap configuration to be tolerant of these variations. This allows using inexpensive standard manufacturing processes rather than expensive precision machining, and cores with slight deviations can still be used without rejection.
Solution Approach 2:
The patent changes the geometric parameters from a circular symmetric gap to a rectangular asymmetric gap, which fundamentally alters the tolerance requirements. The rectangular configuration with defined widths W1 and W2 is much more compatible with standard manufacturing capabilities and reduces the need for expensive post-processing machining.
3Ease of manufacture
If standard ferrite core manufacturing is used, then ease of manufacture improves, but manufacturing precision deteriorates (+/-2% size variation)
Solution Approach 1:
The patent anticipates the +/-2% size variation from sintering and designs the rectangular gap configuration to accommodate this variation. The asymmetric rectangular geometry provides built-in tolerance buffering, allowing standard ferrite cores with typical size variations to be assembled without requiring additional precision machining to achieve the target +/-0.05mm gap tolerance.
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 production costs, improves inverter efficiency, and enhances the viability of planar inductor design by allowing for high-performance inductors with adjustable gaps using standard manufacturing processes.
Implementation Method 1
Magnetic components in power electronic circuits (e.g., inverters) can have an air gap in a magnetic path which can be used to adjust an inductance value
Implementation Method 2
the air gap allows higher bias currents to be applied before the inductance (e.g., magnetic material) saturates
Data Source
AI summary
The present disclosure provides a full inductor core configured for use with a power converter of an energy management system. For example, the full inductor core comprises a first planar inductor comprising a first inner core and a first outer core and a second planar inductor disposed on top of the first planar inductor and comprising a second inner core and a second outer core. The first inner core and first outer core and the second inner core and second outer core each have a sawtooth configuration that allows the full inductor core to be tuned during assembly of the full inductor core.