Coupled-Inductor Power Converter With SCCM Reverse Current Control

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Solution Overview

Problem

Power converters, particularly those using coupled inductors, face challenges in efficiently controlling current flow and reducing complexity in operational modes, leading to issues with mutual inductance and reverse current restriction.

Innovation Solution

The introduction of a Semi-Continuous Current Mode (SCCM) operational mode, where one switch is maintained in a non-conducting state, and the use of a coupled inductor with buck and boost converters sharing a common core, allows for reduced complexity in control and minimizes reverse current flow by restricting current to one direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a coupled inductor is used in a buck-and-boost power converter, then the power conversion efficiency is improved and the device size is reduced, but the control complexity increases due to mutual inductance and bidirectional current flow requirements

Engineering Contradiction:
Improvepower conversion efficiencyVSAvoidcontrol complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent divides the operation into distinct modes (CCM and SCCM) with clear boundary conditions. By segmenting the operational space and assigning different control strategies to each mode, the overall control complexity is managed while maintaining the efficiency benefits of the coupled inductor architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent inverts the conventional approach by restricting current flow to one direction only during SCCM operation, rather than allowing bidirectional flow. This inversion simplifies the control logic by eliminating the need to manage reverse current, while still achieving efficient power conversion through the coupled inductor.

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If Continuous Current Mode (CCM) is used with bidirectional current flow, then the power converter achieves flexible voltage conversion, but the control algorithm complexity and reverse current management difficulty increase

Engineering Contradiction:
Improvevoltage conversion flexibilityVSAvoidcontrol algorithm complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic mode switching between CCM and SCCM based on real-time operating conditions. The controller dynamically adjusts the operational mode to optimize performance while managing complexity, transitioning to SCCM when simplicity is prioritized and to CCM when maximum versatility is needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters by introducing SCCM as an alternative to traditional CCM. This parameter change (from bidirectional to unidirectional current flow) fundamentally alters the control requirements, reducing algorithm complexity while maintaining adaptability through mode selection.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If Semi-Continuous Current Mode (SCCM) is used with unidirectional current flow, then the control complexity is reduced and reverse current is restricted, but the operational flexibility compared to bidirectional modes is limited

Engineering Contradiction:
Improvecontrol complexityVSAvoidoperational flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent makes the power converter universal by implementing multiple operational modes (CCM and SCCM) within the same hardware architecture. The coupled inductor topology supports both bidirectional and unidirectional current flow modes, allowing the device to adapt to different application requirements without hardware changes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The controller automatically selects the appropriate operational mode based on system conditions, eliminating the need for external intervention to determine the optimal mode. The system self-adjusts between CCM and SCCM to maintain optimal performance while managing control complexity.

Inventive Principle:
Principle #25Self-service

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 enhances the efficiency of power conversion by reducing the complexity of control algorithms and minimizing reverse current issues, leading to improved performance and cost-effectiveness in power converter designs.

Implementation Method 1

a coupled inductor with buck and boost converters sharing a common core

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4475418A1Power converter
Publication Date: 2024.12.11 SOLAREDGE TECH LTD
  • EP4475418A1 patent drawingFigure 1A
  • EP4475418A1 patent drawingFigure 1B
  • EP4475418A1 patent drawingFigure 1C

AI summary

A power converter comprising a shared coupled inductor having windings around a common core, a plurality of buck converters and a boost converter. The plurality of buck converters are coupled between a first terminal and a second terminal. The plurality of buck converters comprises a plurality of buck switching legs and the shared coupled inductor. The boost converter is coupled between a third terminal and a fourth terminal. The boost converter comprises a boost switching leg and the shared coupled inductor.