Compact On-Vehicle Reactor With Gapless Composite Core
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Solution Overview
Problem
Reactor size needs to be reduced to minimize installation space in hybrid electric vehicles, as conventional reactors occupy a large volume within converters.
Innovation Solution
A reactor design with a reduced distance between the coil and magnetic core, utilizing a coil formed by connected wound wire elements and a magnetic core composed of divided pieces without gaps, made of hardened composite material, to minimize size and prevent leakage flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the distance between the coil and magnetic core is reduced to minimize reactor size, then the volume of the reactor is decreased, but leakage flux may increase causing energy loss
Solution Approach 1:
The magnetic core is divided into multiple divided core pieces that are arranged and combined to form the complete magnetic core structure. This segmentation allows for optimized positioning of each piece to minimize leakage flux while maintaining compact reactor dimensions, effectively resolving the contradiction between reduced volume and energy loss.
Solution Approach 2:
A resin layer is introduced as an intermediary material between the coil and the divided core pieces. This resin serves multiple functions: it maintains the minimal distance (0.1mm to 2mm) for compact size, provides electrical insulation to prevent short circuits, and fills gaps to reduce leakage flux, thereby resolving the contradiction between small volume and energy efficiency.
2Volume of stationary object
If divided core pieces are combined without gaps to reduce reactor size, then the distance between coil and magnetic core is minimized, but manufacturing precision requirements increase
Solution Approach 1:
The resin acts as an intermediary that compensates for dimensional variations and assembly tolerances of the divided core pieces. By filling the spaces between core pieces and providing a bonding medium, the resin enables gapless combination without requiring extremely tight manufacturing precision, thus achieving compact reactor volume while maintaining manufacturability.
Solution Approach 2:
The resin's fluidity before hardening and rigidity after hardening are utilized to achieve precise positioning. The resin is applied in a fluid state to fill all gaps uniformly, then hardened to lock the divided core pieces in their optimal positions, ensuring minimal distance and proper alignment without demanding extreme manufacturing precision.
3Volume of stationary object
If the reactor size is reduced for on-vehicle converter application, then installation space is minimized, but the structural integrity and reliability may be compromised
Solution Approach 1:
The reactor employs composite materials including divided core pieces made of magnetic powder compacted with resin, and additional resin as bonding material. These composite structures provide high strength-to-volume ratio, ensuring structural integrity and reliability while maintaining compact dimensions suitable for on-vehicle converters with limited installation space.
Solution Approach 2:
The divided core pieces are pre-processed and pre-positioned with the resin before final assembly. This preliminary preparation ensures proper alignment and structural configuration is achieved before the reactor is installed in the converter, maintaining reliability while minimizing the final reactor volume for on-vehicle application.
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 reduces the reactor's size, preventing leakage flux and allowing for smaller converters and power conversion devices suitable for on-vehicle use.
Implementation Method 1
a magnetic core which is obtained by combining a plurality of divided core pieces without a gap provided therebetween
Implementation Method 2
All of the divided core pieces are made of a hardened compact obtained by hardening a resin of a composite material containing magnetic powder and the resin
Data Source
AI summary
A reactor includes a coil formed by connecting a pair of coil elements configured by a wound wire, and magnetic core. The reactor for an on-vehicle converter converts an input voltage. Electricity applying conditions include a maximum DC current of 100 A or higher and 1000 A or lower, an average voltage of 100 V or higher and 1000 V or smaller, and a usable frequency of 5 kHz or higher and 100 kHz or smaller. The magnetic core is obtained by combining a plurality of divided core pieces without a gap provided. All the divided core pieces are made of hardened compact obtained by hardening resin of composite material containing magnetic powder and the resin. A distance between an inner peripheral surface of the coil element and an outer peripheral surface of the magnetic core opposite to the inner peripheral surface is 0.1 mm or more and 2 mm or less.