Series Power Converter Bypass Switch Protection Against Overvoltage Faults

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Solution Overview

Problem

Conventional series converter systems fail to address faults in short-circuiting switches that bypass faulty power converter units, leading to the entire system being stopped.

Innovation Solution

A power conversion system with short-circuiting switches and overvoltage suppressing elements connected in parallel, where the conducting states of these elements are changed by a prescribed voltage, ensuring the system can continue operation even when a power converter unit fails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If short-circuiting switches are provided to bypass faulty power converter units, then the system can continue operation when a power converter unit fails, but the short-circuiting switches themselves may experience faults that stop the entire system

Engineering Contradiction:
Improvesystem continuityVSAvoidswitch fault vulnerability
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Overvoltage suppressing elements are introduced as intermediary protective components connected in parallel with the short-circuiting switches. These elements act as mediators that suppress overvoltages generated during switch operation, preventing voltage-induced faults in the short-circuiting switches while maintaining their bypass functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The overvoltage suppressing elements provide beforehand cushioning by being pre-configured to suppress overvoltages before they can cause damage to the short-circuiting switches. This preventive measure cushions the switches against voltage spikes that would otherwise lead to system failure.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If overvoltage suppressing elements are connected in parallel with short-circuiting switches, then switch faults are suppressed, but the system requires additional components that increase complexity

Engineering Contradiction:
Improveswitch fault suppressionVSAvoidcomponent quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The overvoltage suppressing elements serve multiple functions: they suppress overvoltages to prevent switch faults, and they can also handle fault currents. This multi-functionality reduces the need for additional dedicated protective components, thereby limiting the increase in system complexity.

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

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 system effectively prevents faults in short-circuiting switches, enhancing reliability and redundancy by bypassing faulty units and maintaining power supply.

Implementation Method 1

overvoltage suppressing elements that are connected in parallel with the short-circuiting switches and in which conducting states are changed by an application of a prescribed voltage

Methodology Applied
Scientific EffectOvervoltage suppression: Electrical Resistance

Data Source

PatentEP4117162B1Power conversion system
Publication Date: 2025.12.24 HITACHI LTD
  • EP4117162B1 patent drawingFigure 1
  • EP4117162B1 patent drawingFigure 2~5
  • EP4117162B1 patent drawingFigure 6~7

AI summary

Provided is a power conversion system which can suppress a fault in a short-circuiting switch that bypasses a fault unit and enhance the reliability and redundancy of the system. The power conversion system (100) is provided with a plurality of power converter units (10) that are formed by using semiconductor switch elements and are connected in series, and comprises: switch elements (201, 211) that are provided to input terminals and/or output terminals of the power converter units (10) and bypass the power converter units (10); and overvoltage suppressing elements (202, 212) which are connected in parallel with the switch elements (201, 211) and in which conducting states are changed by an application of a prescribed voltage.