Coupled Inductor Phase Shifting for Low Core-Loss Power Converters
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Solution Overview
Problem
Switching power converters experience significant losses due to high magnetic flux density in the magnetic core, particularly in coupled inductors, leading to increased core losses.
Innovation Solution
The implementation of a multi-phase switching power converter with a coupled inductor, where the phases are controlled to generate periodic voltage waveforms with a phase shift, ensuring that consecutive peak magnitude portions are not applied to immediately adjacent windings, thereby distributing and minimizing the changing magnetic flux density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional switching power converters operate with high switching frequencies to achieve compact size and fast response, then productivity and responsiveness are improved, but magnetic core losses increase significantly due to high magnetic flux density
Solution Approach 1:
The patent applies periodic action by implementing multi-phase switching where phases are sequentially activated in a periodic manner. Each phase operates at a lower frequency while the combined system achieves high effective switching frequency. The periodic activation of phases with optimized phase shifting distributes magnetic flux density over time, reducing peak flux density and associated core losses while maintaining high overall productivity.
Solution Approach 2:
The patent segments the switching operation into multiple phases, where each phase handles a portion of the total power conversion. This segmentation allows each individual phase to operate at lower magnetic flux density levels compared to a single-phase system operating at high frequency. The coupled inductor structure further segments the magnetic flux paths, enabling parallel operation with reduced losses.
2Device complexity
If coupled inductors are used to achieve magnetic coupling between phases for compact design, then device complexity is reduced and space is saved, but magnetic core losses increase due to mutual inductance and flux interactions
Solution Approach 1:
The patent applies local quality by optimizing the magnetic coupling characteristics of the coupled inductor. Different regions of the coupled inductor are designed with specific coupling coefficients - some windings are strongly coupled while others have controlled leakage inductance. This local optimization of magnetic coupling properties allows the system to achieve compact design with reduced core losses by minimizing flux interactions in critical regions while maintaining necessary coupling in other areas.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the operating points and phase shifting angles to optimize the magnetic coupling effects. The coupled inductor parameters (mutual inductance, leakage inductance, core material properties) are specifically selected and tuned to minimize core losses at the operating frequency range, allowing compact design without excessive losses.
3Ease of operation
If phases are consecutively fired to simplify control logic, then ease of operation is improved, but magnetic flux density peaks occur in adjacent windings leading to increased core losses
Solution Approach 1:
The patent implements dynamics by using adaptive phase shifting control where the phase relationship between consecutive phases is dynamically adjusted based on operating conditions. Rather than fixed sequential firing, the control system optimizes phase timing in real-time to distribute peak flux density across non-adjacent windings. This dynamic control maintains ease of operation through automated control logic while effectively reducing magnetic core losses through optimized phase sequencing.
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 approach effectively reduces magnetic core losses and minimizes the susceptibility to magnetic core saturation, allowing for potentially lower switching frequencies and more efficient operation.
Implementation Method 1
coupled inductor is a device including two or more inductors that are magnetically coupled. A coupled inductor exhibits magnetizing or mutual inductance, which is inductance associated with magnetic flux linking the windings of the coupled inductor
Implementation Method 2
A coupled inductor exhibits magnetizing or mutual inductance, which is inductance associated with magnetic flux linking the windings of the coupled inductor
Data Source
AI summary
A method for reducing magnetic core losses in a multi-phase switching power converter including a coupled inductor. The method includes (a) generating a plurality of periodic voltage waveforms, each periodic voltage waveform being applied across a respective winding of a plurality of windings of the coupled inductor, and (b) distributing flow of changing magnetic flux in a magnetic core of the coupled inductor by controlling phase shift among the plurality of periodic voltage waveforms such that at least two consecutive peak magnitude portions of the plurality of periodic voltage waveforms are not applied to respective windings of the plurality of windings of the coupled inductor that are immediately physically adjacent to each other.