Annular Reactor Core Protrusion Gap Ratio Copper Loss
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Solution Overview
Problem
Conventional reactor cores with multiple-gap structures experience increased copper losses due to magnetic flux leakage, with limited technical consideration for suppressing these losses.
Innovation Solution
An annular reactor core design featuring core joints with protrusions extending toward core legs, optimized gap ratios between core joints and legs, and a compacted body of magnetic powder and resin, which reduces copper losses by controlling magnetic flux reflux and fringing flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gaps are provided in the reactor core to reduce effective magnetic permeability and avoid core saturation, then core saturation is avoided, but fringing magnetic flux is generated causing increased copper losses
Solution Approach 1:
A non-magnetic member (intermediary) is inserted into the gap to suppress fringing magnetic flux. This intermediary component prevents magnetic flux from leaking outside the magnetic path, thereby reducing eddy currents in the coil and copper losses, while maintaining the gap's function of preventing core saturation
Solution Approach 2:
The gap length is optimized to be 0.5mm or more but 5mm or less, and the ratio of gap length to core leg length is controlled within 1/20 to 5/20. By changing these dimensional parameters, the patent achieves a balance between preventing core saturation and minimizing fringing flux effects
2Loss of energy
If multiple-gap structures are used to suppress fringing flux, then copper losses are reduced, but the device complexity increases
Solution Approach 1:
Instead of uniformly distributing multiple gaps throughout the core, the patent strategically places a single gap at a specific location where fringing flux has the most significant impact. The non-magnetic member is positioned locally at this critical gap, achieving effective flux suppression without the complexity of multiple gaps throughout the entire core structure
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 design effectively suppresses copper losses and achieves a high-efficiency reactor core with reduced coil AC resistance, suitable for hybrid electric vehicles and power conditioners.
Implementation Method 1
Powder magnetic cores are obtained by working and molding after the surface of magnetic powders is subjected to an insulating process, and the occurrence of eddy current losses is suppressed by the insulating process
Implementation Method 2
the effective magnetic permeability μre is reduced by providing gaps in this core material, and a necessary inductance is obtained by adjustment with respect to the number of windings
Implementation Method 3
an eddy current is generated on the coil surface in the vicinity of the gaps, thereby posing the problem that losses increase
Data Source
AI summary
Provided is an annular reactor core formed of a U-shaped core and core legs. Core joints including end portions and two protrusions form the U-shaped core. Between the protrusions of these core joints, a plurality of (two) core legs 6 formed of core blocks are arranged so as to have gaps and the protrusions. The ratio A/B, which is a ratio of the length A of the protrusions of the core joint to the average length B of the core blocks constituting the core legs in a magnetic path direction, is optimized so as to be not less than 0.3 but not more than 8.0, whereby an increase in copper loss due to leak magnetic fluxes of the gap portions is suppressed.