Matrix Converter Segmentation for Thyristor Load Reduction

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Solution Overview

Problem

Existing electrical circuits using matrix converters for generating electrical energy face high loads on thyristors due to short current-carrying times, leading to current peaks.

Innovation Solution

An electrical circuit with an n-phase generator, a converter comprising m sub-converters, and a transformer, where the switching devices are symmetrically connected to the generator, reducing current peaks and increasing thyristor current duration by a factor of m, thereby lowering loads on switching devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a matrix converter is used to allow the generator to operate at higher frequency, then the generator can be operated at higher frequency, but the existing thyristors only have short current-carrying times which leads to current peaks and high loads

Engineering Contradiction:
Improvegenerator operating frequencyVSAvoidthyristor current-carrying time
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The converter is divided into m sub-converters, each with p blocks. This segmentation distributes the total current among multiple parallel paths, reducing the current burden on individual thyristors and extending their effective current-carrying time while maintaining the ability to operate the generator at higher frequencies

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple sub-converters are connected in parallel to combine their current-carrying capabilities. The symmetrical connection of switching devices from different sub-converters to the same generator phases creates redundant current paths, effectively multiplying the current-carrying time by factor m while sharing the load

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If thyristors have short current-carrying times, then the converter can be simpler, but this leads to current peaks and high loads on switching devices

Engineering Contradiction:
Improveconverter structureVSAvoidload on switching devices
Core Design Contradiction:
Device complexityVSStress or pressure

Solution Approach 1:

The converter structure is segmented into m sub-converters with symmetrical connection to the generator. This segmentation distributes the current load across multiple parallel switching paths, reducing the stress on individual switching devices by factor m while maintaining a relatively simple overall converter architecture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The symmetrical connection arrangement acts as an intermediary between the generator and the switching devices. It redistributes the current flow through multiple parallel paths, effectively reducing the peak current and load stress on individual switching devices without requiring complex control mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively reduces the load on switching devices by a factor corresponding to the number of sub-converters, minimizing current peaks and extending thyristor current conduction duration, resulting in lower operational stress and improved efficiency.

Implementation Method 1

a turbine 11 which is mechanically coupled directly to an electrical generator 12... the generator 12 is also set in rotary motion and thus generates an output voltage with a speed-dependent frequency in generator mode

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The output voltage is increased by means of the transformer 14 to a predetermined voltage... the transformer 14 is also connected to an electrical load, not shown

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2302777B1Electrical circuit, particularly for generating electrical energy
Publication Date: 2017.09.06 GE ENERGY POWER CONVERSION TECHNOLOGY LTD(GB)
  • EP2302777B1 patent drawingFigure 1
  • EP2302777B1 patent drawingFigure 2
  • EP2302777B1 patent drawingFigure 3

AI summary

The circuit has a transformer (14) to which a p-phase load is connected. A converter (13) is composed of m partial converters (171-173), where each of the m partial converters is subdivided into p units (161-169) that include n/m switching circuits (23). The n/m switching circuits of the p units are connected symmetrically to an n-phase generator (12), where the n/m switching circuits are provided with two thyristors that are switched parallel in opposite directions. Windings (19-22) of the n-phase generator are connected in series relative to each other.