Cascaded Multi-Phase Buck-Boost Cells for Wide-Range Voltage Regulation

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Solution Overview

Problem

Existing power conversion systems struggle to achieve high efficiency under varying operating conditions, particularly in high step-down and high step-up voltage ratio applications, due to limitations in voltage regulation and electromagnetic interference.

Innovation Solution

A hybrid buck-boost power conversion system comprising a plurality of buck-boost cells, where power conversion cells are connected in cascade and operate in multiple phases, allowing for dynamic adjustment of operating phases and duty cycles to maintain efficient voltage regulation and reduce electromagnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a direct-to-chip power architecture is employed to efficiently power low-voltage, high current loads, then power delivery capability is improved, but switching elements must operate at a small duty cycle and inductors endure high current stress

Engineering Contradiction:
Improvepower delivery capabilityVSAvoidswitching operation complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The power conversion system is divided into multiple buck-boost cells operating in different phases. Each cell handles a portion of the total power conversion task, distributing the stress and complexity across multiple simpler units rather than requiring a single complex switching element to operate at extreme duty cycles

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the operating phases and duty cycles of individual buck-boost cells based on load conditions. This allows the system to maintain optimal switching characteristics across varying power demands, avoiding the fixed small duty cycle operation required by traditional direct-to-chip architectures

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If switch-capacitor power converters are used to achieve high efficiency for high voltage ratio applications, then conversion efficiency is improved, but the voltage conversion ratio is fixed and output voltage cannot be regulated under various operating conditions

Engineering Contradiction:
Improveconversion efficiencyVSAvoidvoltage regulation capability
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The system employs multiple buck-boost cells that can be dynamically activated or deactivated based on operating conditions. Each cell contributes to the overall voltage conversion, and their combined output can be regulated to maintain stable voltage across varying input voltages and load conditions, unlike fixed-ratio switch-capacitor converters

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The buck-boost cells serve multiple functions: they provide voltage step-down, voltage step-up, and output voltage regulation capabilities within a single system. This multi-functionality allows the system to adapt to various operating conditions while maintaining high efficiency, overcoming the fixed-ratio limitation of traditional switch-capacitor converters

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

3Object-affected harmful factors

If multiple buck-boost cells operate in cascade with multiple phases, then voltage regulation and electromagnetic interference reduction are improved, but system complexity increases

Engineering Contradiction:
Improveelectromagnetic interferenceVSAvoidsystem structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system segments the power conversion function into multiple phases with interleaved switching. This segmentation distributes the electromagnetic interference across different time slots and frequency spectra, reducing overall EMI impact while maintaining a structured, manageable system architecture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multiple buck-boost cells operate in periodic, interleaved phases with coordinated switching. This periodic action creates predictable electromagnetic patterns that can be filtered and managed more effectively than random or simultaneous switching, reducing EMI while organizing system complexity into a rhythmic, controllable structure

Inventive Principle:
Principle #19Periodic action

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

The hybrid system achieves high efficiency and effective voltage regulation across a wide range of operating conditions, reducing electromagnetic interference and improving load transient response.

Implementation Method 1

an inductor connected between a common node of the high-side switch and the low-side switch and an output terminal

Methodology Applied
Scientific EffectMagnetic field energy storage: Inductor

Implementation Method 2

a capacitor connected between a first node and a second node

Methodology Applied
Scientific EffectElectrical charge storage: Capacitance

Data Source

PatentEP3895299B1Hybrid power converter and method
Publication Date: 2024.06.19 HUAWEI DIGITAL POWER TECH CO LTD
  • EP3895299B1 patent drawingFigure 1~2
  • EP3895299B1 patent drawingFigure 3~4
  • EP3895299B1 patent drawingFigure 5

AI summary

A method includes configuring N power conversion cells to operate in M operating phases, wherein N and M are predetermined integers, and wherein M is less than or equal to N, and M is greater than or equal to 2, and configuring two adjacent power conversion cells of the N power conversion cells to operate in two different operating phases, wherein the N power conversion cells are connected in cascade between a power source and a load, and wherein a maximum duty cycle of each power conversion cell is in a range from 1/M to 1/2.