Twisted-core coupled inductor for power converter transient response
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Solution Overview
Problem
In power converters, such as multi-phase buck converters, there is a conflict between achieving high efficiency and fast load transient response, as larger inductance reduces inductor current ripple but increases transient response time, leading to output voltage overshoot and undershoot.
Innovation Solution
The use of an inverse-coupled inductor with a twisted core structure and strategically placed gaps to independently control leakage and mutual inductance, allowing for reduced winding length and DC resistance, and shielding windings to minimize Electromagnetic Interference (EMI).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If larger inductance is used to reduce inductor current ripple, then efficiency is improved, but transient response time increases leading to output voltage overshoot and undershoot
Solution Approach 1:
The patent segments the magnetic core into multiple pieces (first core piece, second core piece, third core piece, fourth core piece) arranged in a twisted configuration. This segmentation allows independent control of magnetic flux paths for each winding, enabling simultaneous optimization of current ripple reduction and transient response through separate gap adjustments on different core pieces.
Solution Approach 2:
The patent implements local quality by placing gaps at specific locations on different core pieces (first gap on first core piece, second gap on second core piece, etc.). Each gap locally adjusts the magnetic reluctance for specific flux paths, allowing differential control of inductance characteristics to resolve the contradiction between ripple reduction and transient response.
2Area of stationary object
If coupled inductor structure is used to save space, then area utilization is improved, but winding complexity and EMI increase
Solution Approach 1:
The patent uses an asymmetric twisted core structure where core pieces are arranged in a non-symmetric configuration with windings on opposite sides. This asymmetric design creates opposing magnetic flux paths that naturally cancel each other's electromagnetic fields, reducing EMI while maintaining compact space utilization.
Solution Approach 2:
The patent converts the potentially harmful EMI generated by coupled windings into a beneficial cancellation effect. By arranging windings on opposite sides of the twisted core structure, the magnetic fields that would normally cause interference are made to oppose and cancel each other, transforming EMI from a harmful factor to a space-saving advantage.
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 design enhances space utilization, mechanical robustness, and noise reduction, improving the performance of power converters by simplifying the integration with surrounding circuitry and reducing winding losses while maintaining high efficiency and fast transient response.
Implementation Method 1
The assembled core structure can be a substantially rectangular block forming a magnetically closed-loop around the first and second straight winding portions
Implementation Method 2
The core structure can include a first zig-zag shaped gap, generating a first clearance between at least two portions of the closed-loop magnetic core structure
Data Source
AI summary
A device may include a coupled inductor structure comprising a first winding portion, a second winding portion, and a magnetic core structure. The magnetic core structure may include a first and second core piece that are at least partially cross-sectionally U-shaped. A first connecting core piece may be attached to a first portion of the first core piece to a first portion of the second core piece, and a second connecting core piece may attach a second portion of the first core piece to a second portion of the second core piece.