Coupled-Inductor DC-DC Converter Ripple Reduction
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Solution Overview
Problem
High-power DC-DC converters face challenges in reducing output current ripple and minimizing magnetic material usage, leading to inefficiencies in space and cost due to the need for multiple conversion stages and bulky transformer-based designs with separate inductors and transformers.
Innovation Solution
A DC-DC power converter design that integrates transformer and inductor magnetic ferrite cores into a single structure, with optimally defined winding polarities and magnetic coupling, allowing concurrent switching of primary and secondary switches to avoid resonant energy storage and reduce inductance requirements, thereby minimizing output current ripple and magnetic core volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If separate transformers and inductors are used in 48V to sub 1V DC-DC converters, then voltage transformation and current delivery are achieved, but magnetic ferrite core volume increases significantly
Solution Approach 1:
The patent combines the transformer and inductor magnetic ferrite cores into a single integrated structure. The transformer primary and secondary windings are wound on one leg of the magnetic core, while the inductor winding is wound on another leg, allowing both functions to share common magnetic material and reduce overall volume.
Solution Approach 2:
The integrated magnetic core structure serves multiple functions simultaneously: it provides both transformer action for voltage transformation and inductor function for current delivery and ripple reduction. The shared magnetic core enables a single component to perform what traditionally required separate transformer and inductor components.
2Power
If transformer-based designs with separate inductors are used, then voltage transformation is achieved, but space efficiency decreases
Solution Approach 1:
The patent merges the transformer and inductor into a single integrated magnetic component, eliminating the need for separate magnetic cores and reducing the overall converter volume. The shared magnetic structure allows both voltage transformation and current delivery functions within a compact form factor.
3Power
If traditional transformer-based converters are used, then power conversion is achieved, but output current ripple increases
Solution Approach 1:
The integrated magnetic structure with coupled transformer and inductor windings creates magnetic coupling that reduces output current ripple. The shared magnetic core enables the inductor function to actively filter ripple current while the transformer performs voltage transformation, achieving both functions with reduced harmful effects.
4Power
If multiple power conversion stages are used (48V to 12V then 12V to processor voltage), then voltage transformation is achieved, but power loss and volume increase
Solution Approach 1:
The patent extracts and eliminates the intermediate 12V conversion stage from the power conversion chain. The converter directly transforms 48V input to the required sub 1V processor voltage in a single stage, removing the unnecessary intermediate conversion step that would otherwise cause additional power losses and require additional components.
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 achieves reduced output current ripple, lower voltage noise, improved time response, and increased space efficiency by minimizing the magnetic core volume and inductor value, making it competitive with traditional buck converters while operating at higher input voltages.
Implementation Method 1
a transformer with a primary winding and a secondary winding
Implementation Method 2
the relative timing of the switches on the primary and secondary sides of the transformer is defined so as to turn on both the primary main switches and the secondary main switches concurrently and to thereby avoid resonant energy storage
Data Source
AI summary
A DC-to-DC power converter device has a common magnetic core structure that serves the functions of both transformer device and output inductor by integrating each into the common core. The transformer device has primary and secondary windings integrated into a first leg structure of the magnetic core, and the output inductor device has an output inductor winding integrated into a second leg structure of the magnetic core, the inductor winding structure for delivering output current to a load when a periodically switched input voltage is applied across the primary winding structure. The winding polarities of the transformer secondary winding structure and of the output inductor winding structure provide oppositely oriented polarities of electromotive force (EMF) to substantially reduce an output current ripple to an output load when delivering power through the transformer, through the output inductor and into the output load. A third leg structure of the common magnetic core allows magnetic flux passing through the transformer leg structure to partially magnetically couple to flux passing through the inductor leg structure, thereby allowing adjustment of the output voltage at which output current ripple is minimized.