Power Conversion Device Flux Counteraction
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Solution Overview
Problem
In conventional non-isolated step-down applications with large current, unequal DC currents through inductors lead to excessive DC magnetic fluxes on side pillars, causing magnetic core saturation and increased power conversion losses.
Innovation Solution
A power conversion device with multiple inductors wound around the side pillars of magnetic components, where corresponding inductors have equal DC currents, allowing DC magnetic fluxes to counteract each other without air gaps, and control signals are used to manage phase differences for AC flux counteraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If windings of plural inductors are wound around the side pillars of the same magnetic component, then AC magnetic fluxes on the middle pillar can be counteracted reducing output current ripple, but DC magnetic fluxes on the side pillars become large causing magnetic core saturation
Solution Approach 1:
The patent applies asymmetry by placing air gaps selectively only on the middle pillar of the magnetic component, while the side pillars remain without air gaps. This asymmetric configuration allows the DC magnetic fluxes on the side pillars to be counteracted by equal and opposite fluxes from corresponding inductors, preventing saturation, while the middle pillar's air gap handles the AC flux counteraction to reduce output ripple.
2Object-affected harmful factors
If air gaps are disposed on side pillars to prevent magnetic core saturation, then DC magnetic flux saturation is reduced, but power conversion losses increase
Solution Approach 1:
The patent applies local quality by differentiating the magnetic path characteristics of different pillars. The middle pillar is equipped with an air gap to handle AC flux variations, while the side pillars are kept without air gaps to minimize losses, relying on the counteraction principle for DC flux management. This localized differentiation optimizes both saturation prevention and efficiency.
3Loss of energy
If DC currents through corresponding inductors are made equal, then DC magnetic fluxes can be counteracted without air gaps on side pillars, but device complexity increases
Solution Approach 1:
The patent employs feedback control through a controller that receives current detection signals from each power conversion circuit and adjusts the duty ratios of corresponding switches to equalize the DC currents through corresponding inductors. This feedback mechanism automatically maintains current balance, enabling DC flux counteraction without side pillar air gaps while managing the complexity through automated control.
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 reduces power conversion losses, prevents magnetic core saturation, and minimizes the size of magnetic components by counteracting DC and AC magnetic fluxes, thereby enhancing efficiency and reducing output current ripple.
Implementation Method 1
the windings of these corresponding inductors are wound around the side pillars of the same magnetic component, thus the DC magnetic fluxes on the side pillars can be counteracted by each other
Implementation Method 2
The middle pillar has an air gap. In the N power conversion circuits, windings of N corresponding inductors which are corresponding to each other are wound around the N side pillars of one of the M magnetic components
Data Source
AI summary
A power conversion device is provided. The power conversion device includes N power conversion circuits and M magnetic components, where N and M are positive integers greater than 1. Each of the N power conversion circuits includes M inductors. DC currents flowing through the M inductors respectively are unequal. Each one of the M inductors in different ones of the N power conversion circuits corresponds to each other to form a group of N corresponding inductors. In the N power conversion circuits, DC currents respectively flowing through the corresponding inductors are equal. Each of the M magnetic components includes a middle pillar, N side pillars and two substrates. The middle pillar has an air gap. In the N power conversion circuits, windings of N corresponding inductors are respectively wound around the N side pillars of one of the M magnetic components.