Switched-Capacitor Power Converter for Flexible High-Voltage Gain

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Solution Overview

Problem

High-voltage-gain DC/DC converters for distributed energy resources face efficiency limitations due to parasitic resistance, leakage inductance, and high voltage stress, particularly in high-temperature environments, where magnetic-based converters are unsuitable and existing switched-capacitor converters require numerous components or suffer from rigid voltage conversion ratios.

Innovation Solution

A power converter using a switched-capacitor structure with multiple switch blocks, flying capacitors, and bypass capacitors to achieve flexible and high-efficiency voltage conversion, reducing switch and capacitor stress, and enabling operation in high-temperature environments with fewer components and adjustable conversion ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If magnetic-based converters with transformer are used to achieve high voltage gain, then voltage conversion ratio is improved, but converter efficiency deteriorates due to high voltage stress and leakage inductance losses

Engineering Contradiction:
Improvevoltage conversion ratioVSAvoidconverter efficiency
Core Design Contradiction:
Stress or pressureVSLoss of energy

Solution Approach 1:

The patent extracts and removes the magnetic components (transformer and inductor) from the converter topology, creating a magnetic-less switched-capacitor based converter. This eliminates the sources of magnetic losses including leakage inductance and core losses, thereby improving converter efficiency while maintaining high voltage gain capability through capacitive energy transfer

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the magnetic field-based energy transfer mechanism with an electric field-based switched-capacitor mechanism. Instead of using transformer inductors for voltage transformation, the invention uses capacitors and switches to achieve the same voltage gain, replacing electromagnetic induction with capacitive charging/discharging cycles

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Stress or pressure

If magnetic-based converters are used in high temperature environment, then voltage conversion is achieved, but converter performance deteriorates due to decreased magnetic permeability

Engineering Contradiction:
Improvevoltage conversion capabilityVSAvoidconverter performance in high temperature
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The patent removes magnetic components from the converter topology, eliminating the temperature-sensitive magnetic permeability characteristic. By using only capacitors and switches, the converter becomes insensitive to high temperature effects that degrade magnetic material performance, ensuring reliable operation in high temperature environments

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental operating parameters of the converter by eliminating magnetic materials and their associated permeability characteristics. The switched-capacitor topology operates based on capacitive reactance and switching timing, which are not significantly affected by temperature variations, thereby maintaining stable performance across wide temperature ranges

Inventive Principle:
Principle #35Parameter changes

3Stress or pressure

If conventional switched-capacitor converters are used for high voltage gain, then voltage conversion is achieved, but device complexity increases due to numerous components required

Engineering Contradiction:
Improvevoltage gain capabilityVSAvoidnumber of components
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The patent divides the high voltage gain conversion into multiple stages, each providing moderate voltage multiplication. By cascading several switched-capacitor stages, the overall high voltage gain is achieved while keeping each individual stage simple with fewer components per stage, reducing total component count and complexity compared to single-stage approaches

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a reconfigurable switched-capacitor topology where the connection configuration of capacitors and switches can be dynamically changed through control signals. This dynamic reconfiguration allows the same hardware structure to achieve different voltage gain ratios, reducing the need for multiple fixed-ratio converters and thereby reducing overall device complexity

Inventive Principle:
Principle #15Dynamics

4Stress or pressure

If conventional switched-capacitor converters are used for high voltage gain, then voltage conversion is achieved, but conversion ratio flexibility is limited due to rigid structure

Engineering Contradiction:
Improvevoltage conversion capabilityVSAvoidconversion ratio flexibility
Core Design Contradiction:
Stress or pressureVSAdaptability or versatility

Solution Approach 1:

The patent implements a reconfigurable switched-capacitor topology where the connection configuration of capacitors and switches can be dynamically changed through control signals. This dynamic reconfiguration allows the same hardware structure to achieve different voltage gain ratios, providing flexible and adjustable conversion ratios adapted to various operating conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent designs a universal switched-capacitor module that can perform multiple voltage conversion ratios and operating modes using the same set of capacitors and switches. By controlling the switching sequences and connection topologies, the converter can adapt to different input/output voltage requirements, enhancing versatility without requiring multiple dedicated converters

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

Data Source

PatentEP3262743B1Power converter and power conversion method
Publication Date: 2024.02.14 THE UNIVERSITY OF HONG KONG
  • EP3262743B1 patent drawingFigure 1~2
  • EP3262743B1 patent drawingFigure 3
  • EP3262743B1 patent drawingFigure 4~5

AI summary

A power converter comprising one or more switch blocks. Each switch block has: a plurality of switch-pairs each having two switches connected in series to each other; a plurality of primary nodes each interconnecting the switches in a respective switch-pair; and a plurality of secondary nodes, each switch-pair being connected in series to an adjacent switch-pair through a said secondary node to form a serial chain of switch-pairs, the secondary nodes including a secondary node at one end of said serial chain and a secondary node at another end of said serial chain. Each adjacent pair of said primary nodes is connectable to a flying capacitor. Each pair of said secondary nodes is connectable to one or more of the following: one or more bypass capacitors, and one or more other said switch blocks. The power converter further comprises a first terminal formed by any two of the secondary nodes in any one of the switch blocks, and a second terminal formed by any two of the secondary nodes in any one of the switch blocks.