Coupled Inductor Yoke Extension Reduces Leakage Field Eddy Losses
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Coupled inductors in power converters experience significant eddy current losses due to leakage magnetic fields, which reduce efficiency, especially when the load is small and the power converter's power is low.
Innovation Solution
The design incorporates a magnetic core with magnetic cylinders and opposite magnet yokes, where the windings are wound around the cylinders and do not extend beyond the yokes in specific directions, reducing exposure to leakage magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the coupled inductor uses multiple windings around magnetic cylinders with conventional magnet yoke configuration, then the interleaved parallel technology can be implemented to improve on and off frequencies and reduce output ripple current, but a relatively strong leakage magnetic field exists in air which causes eddy current loss in windings
Solution Approach 1:
The patent introduces an intermediate magnetic structure (magnet yoke with extended parts) that acts as a mediator between the windings and the external environment. The extended parts of the magnet yoke create a magnetic shielding effect, providing a controlled magnetic path that reduces the strength of leakage magnetic fields in air, thereby decreasing eddy current losses while preserving the interleaved parallel operation benefits
Solution Approach 2:
The patent converts the harmful leakage magnetic field into a beneficial configuration by using the extended magnet yoke parts to guide and contain the magnetic flux. The leakage flux that would otherwise cause eddy current losses is redirected through the extended yoke structure, transforming the harmful effect into a controlled magnetic path that reduces energy loss
2Volume of stationary object
If the coupled inductor is directly connected to a load to save filter inductor, then costs and system volume can be reduced, but a relatively strong leakage magnetic field exists which may cause eddy current loss in windings
Solution Approach 1:
The extended magnet yoke structure serves as an intermediary element that provides magnetic shielding without requiring additional external filter inductors. This intermediate structure reduces leakage magnetic field strength in the surrounding space, thereby decreasing eddy current losses while maintaining the compact direct-connection configuration that saves system volume
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 configuration minimizes eddy current losses and improves the efficiency of the power converter, especially under low load conditions, by preventing cutting of windings by leakage magnetic fields.
Implementation Method 1
the magnetic core includes at least two magnetic cylinders and two opposite magnet yokes, the at least two magnetic cylinders are disposed between the two opposite magnet yokes
Implementation Method 2
when a relatively high common mode current passes through the coupled inductor, a relatively strong leakage magnetic field exists in air, which may cause an eddy current loss in windings of the coupled inductor
Implementation Method 3
Multiple power bridge arms that are included in the multi-level power converter using the interleaved parallel technology are coupled by using multiple windings or coils in a coupled inductor
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
A coupled inductor (200) and a power converter are disclosed. The coupled inductor includes a magnetic core and at least two windings (231, 232, ..., and 23n). The magnetic core includes at least two magnetic cylinders (241, 242, ..., and 24n) and two opposite magnet yokes (221, 222), the at least two magnetic cylinders are disposed between the two opposite magnet yokes, the at least two windings are respectively wound around the at least two magnetic cylinders, the at least two windings are in a one-to-one correspondence with the at least two magnetic cylinders, and the at least two windings do not extend out of the two opposite magnet yokes in at least one direction, where each direction of the at least one direction is a direction perpendicular to side faces of the two opposite magnet yokes. The two opposite magnet yokes may be extended in at least one direction, so that the at least two windings do not extend out of the two opposite magnet yokes in the at least one direction, which can reduce cutting of winding coils of the inductor by a leakage magnetic field, thereby reducing an eddy current loss caused by the cutting of the winding coils of the inductor by the leakage magnetic field.