Coupled Inductor Array With Embedded Low-Permeability Structure
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Solution Overview
Problem
Existing multi-phase switching power converters face challenges in achieving optimal magnetic coupling and leakage inductance values, which are crucial for efficient energy storage and ripple current cancellation, often resulting in compromised performance due to limitations in core design and material properties.
Innovation Solution
The development of a coupled inductor array with a monolithic magnetic core having a distributed gap, where windings are configured to form loops with a rectangular shape, extending beyond the core's perimeter, and non-magnetic structures are embedded to control magnetic flux, promoting strong magnetic coupling and adjustable leakage inductance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If larger magnetizing inductance values are used to strengthen magnetic coupling, then converter transient response and efficiency are improved, but leakage inductance must be maintained within a relatively small value range to prevent excessive ripple current
Solution Approach 1:
The magnetic core is divided into multiple segments or sections, each contributing to the overall magnetizing inductance. This segmentation allows independent optimization of magnetic coupling paths while controlling leakage inductance through strategic placement of windings and magnetic materials.
Solution Approach 2:
Different regions of the coupled inductor structure are designed with different magnetic properties. High-permeability magnetic materials are positioned in regions where strong coupling is desired, while air gaps or low-permeability materials are strategically placed to control leakage inductance without compromising overall magnetic coupling.
2Object-generated harmful factors
If leakage inductance is increased to prevent excessive ripple current, then ripple current magnitude is reduced, but converter transient response suffers
Solution Approach 1:
The design optimizes the specific parameters of the coupled inductor, including the ratio of magnetizing to leakage inductance, winding configurations, and magnetic core geometry. By carefully selecting these parameters, the system achieves the optimal balance between ripple current suppression and transient response performance.
Solution Approach 2:
The coupled inductor design enables dynamic performance optimization through its magnetic coupling characteristics. The inter-phase coupling allows the inductor to adaptively respond to different operating conditions, maintaining optimal performance across varying load and line conditions.
3Productivity
If multiple discrete inductors are used in multi-phase converters, then converter capacity and performance are improved, but the converter requires larger input and output filtering and has reduced efficiency
Solution Approach 1:
Multiple inductor functions are merged into a single coupled inductor structure. The multi-phase windings are magnetically coupled through a shared magnetic core, combining the energy storage functions of multiple discrete inductors while enabling ripple current cancellation and reducing the need for additional filtering components.
4Reliability
If magnetically coupled inductors are used to cancel ripple current, then transient response is improved, but the inductor structure becomes more complex with associated leakage and magnetizing inductance requirements
Solution Approach 1:
The coupled inductor structure performs multiple functions simultaneously: energy storage for each phase, magnetic coupling for ripple current cancellation, and inherent filtering through its inductance characteristics. This multi-functionality reduces the need for separate filtering components and simplifies the overall converter design.
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 enables strong magnetic coupling and large leakage inductance values, reducing core losses and improving the overall efficiency and transient response of the switching power converter while maintaining a compact design.
Implementation Method 1
a multi-phase switching power converter's performance can be improved by magnetically coupling the energy storage inductors of two or more phases
Implementation Method 2
The N windings pass at least partially through the magnetic core in the lengthwise direction, and each of the N windings forms a loop in the magnetic core around a respective winding axis
Implementation Method 3
Leakage inductance, on the other hand, is associated with energy storage. Thus, the larger the leakage inductance, the more energy stored in the inductor
Data Source
AI summary
A coupled inductor array includes a monolithic magnetic core formed of magnetic materials having a distributed gap, first and second windings, and a low-permeability magnetic structure. The first and second windings form respective first and second winding turns around a common winding axis extending in the height direction. The low-permeability magnetic structure is embedded in the monolithic magnetic core and forms a loop around the common winding axis. The low-permeability magnetic structure separates the first and second winding turns in the height direction, and the low-permeability magnetic structure is formed of a magnetic material having a lower magnetic permeability than the one or more magnetic materials forming the monolithic magnetic core. One possible application of the coupled inductor array is in a multi-phase switching power converter.