Multi-Input Boost Converter with Segmented Chokes

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Solution Overview

Problem

Conventional step-up converters face inefficiencies due to high ripple currents, large choke requirements, high semiconductor load, and additional losses, which increase cost, weight, and volume, while also reducing overall efficiency in inverter circuits, especially when handling fluctuating DC voltages from solar generators.

Innovation Solution

A step-up converter with multiple inputs that allows for series and parallel connections of DC voltage sources via switching elements and inductors, enabling current division and reducing choke size and losses, with semiconductor switches operated statically or clocked for optimal efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a conventional step-up converter is used to boost fluctuating DC voltage from solar generators, then the output voltage can be stabilized, but high ripple currents occur and large chokes are required

Engineering Contradiction:
Improveoutput voltage stabilityVSAvoidchoke size
Core Design Contradiction:
Stability of the object's compositionVSVolume of stationary object

Solution Approach 1:

The patent divides the single choke into multiple smaller chokes (first choke, second choke, third choke) distributed across different circuit paths. Each choke handles a portion of the total current, allowing smaller individual sizes while maintaining the required total inductance. This segmentation reduces the volume of each magnetic component while achieving the same overall energy storage capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple parallel current paths with individual chokes into a unified multi-input converter architecture. The first and second inputs feed through separate choke paths that converge at the switching node, while the third input provides additional current support. This merging of parallel paths distributes ripple current across multiple chokes, reducing the size requirement for each individual choke while maintaining output stability.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If a conventional step-up converter with single input is used, then the circuit is simple, but the load on semiconductor components is high and efficiency is bad

Engineering Contradiction:
Improvecircuit simplicityVSAvoidconverter efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent segments the power processing task across three independent input channels, each with its own choke and switching element. This distribution divides the total current load among multiple semiconductor components (first switching element, second switching element, third switching element), reducing the stress on each individual device and lowering conduction losses.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic switching control where the switching elements operate at different duty cycles based on input voltage levels and power demands. The control unit dynamically adjusts the switching patterns to optimize current distribution, allowing the converter to adapt to varying solar generator outputs and maintain high efficiency across different operating conditions.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the input DC voltage range is limited, then the circuit design is simplified, but fewer module combinations are suitable for solar generators

Engineering Contradiction:
Improvecircuit design simplicityVSAvoidinput voltage range
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal multi-input converter that can accept three different DC voltage sources (first DC voltage source, second DC voltage source, third DC voltage source) with different voltage levels. The circuit architecture allows any combination of these inputs to be activated based on availability, enabling the system to adapt to various solar module configurations while maintaining a unified control scheme.

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

Solution Approach 2:

The patent employs dynamic input selection and switching control that adapts to the actual operating conditions. The control unit monitors the state of each input source and dynamically configures the active circuit paths, allowing the converter to handle a wide range of input voltages from different solar generator configurations without requiring separate circuit designs for each scenario.

Inventive Principle:
Principle #15Dynamics

4Stability of the object's composition

If additional buffering components are added to reduce ripple currents, then output stability improves, but cost, weight, and volume increase

Engineering Contradiction:
Improveoutput voltage stabilityVSAvoidconverter weight
Core Design Contradiction:
Stability of the object's compositionVSWeight of stationary object

Solution Approach 1:

The patent segments the current path into multiple parallel channels, each with its own filtering choke. This distribution of current across multiple smaller chokes reduces the total magnetic material required compared to a single large choke, thereby reducing weight while maintaining equivalent ripple current suppression and output stability.

Inventive Principle:
Principle #1Segmentation

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 solution significantly reduces choke size and losses, lowers semiconductor stress, and enhances overall efficiency, allowing for a wider input voltage range and reduced volume, weight, and cost, while maintaining stable output potentials for improved electromagnetic compatibility.

Implementation Method 1

When the switching element 14 is closed, current flows from the source 10 through the choke 12, with energy being temporarily stored in the choke 12

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

When the switching element 14 is open, the current flows from the source 10 via the freewheeling diode 16 and the inductor 12 into the load

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP2451064B1Boost converter
Publication Date: 2019.06.19 SEW EURODRIVE GMBH & CO KG
  • EP2451064B1 patent drawingFigure 1~3
  • EP2451064B1 patent drawingFigure 4~6
  • EP2451064B1 patent drawingFigure 7~8

AI summary

The converter has inputs to which direct current (DC) power sources (10a-10c) is connectable, and a common output (24) at which DC voltage is provided, where a value of the DC voltage is larger than that of input voltages. The output is connected with the inputs over a positive line and a negative line. Inductors (12a-12d) and rectifier elements (16a-16d) i.e. diodes, are arranged in the positive and negative lines from the inputs. The inputs are switchable in series by switching elements (14a-14d) over the inductors. Two of the inductors are parallely switchable. The switching elements are MOSFETs or insulated gate bipolar transistors (IGBTs). The DC power sources are solar generators, fuel cells, thermoelectric generators, accumulators, batteries, super capacitors, electromagnetic generators, alternating current (AC)/DC converters, DC/DC converters. An independent claim is also included for an inverter circuit comprising a boost converter.