Integrated Rail Power Converter Layout for Fewer Parts

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Solution Overview

Problem

Existing power conversion devices for electric railroad vehicles face challenges in downsizing and improving reliability due to the mixing of various circuits, which complicates the reduction of parts and increases failure risks.

Innovation Solution

A four-phase integrated power conversion device is configured to combine a boosting circuit, overvoltage suppression circuit, and brake chopper circuit into one phase, with three phases forming an inverter, allowing for a reduction in the number of individual parts and enhancing productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If various circuits (boosting circuit, overvoltage suppression circuit, brake chopper circuit) are provided separately in a power conversion device, then each circuit can be optimized for its specific function, but the number of parts increases and the device size increases

Engineering Contradiction:
Improvecircuit optimizationVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple circuits (boosting circuit, overvoltage suppression circuit, brake chopper circuit, and inverter) into a single integrated power conversion device. The semiconductor modules are shared across different circuit functions, reducing the total number of parts while maintaining the ability to optimize each circuit's performance through dedicated control strategies.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The semiconductor modules serve multiple functions across different circuits. The same hardware components are utilized for boosting, overvoltage suppression, brake chopper operations, and inverter functions, making the system multi-functional without requiring separate dedicated components for each circuit.

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

2Reliability

If various circuits are provided separately in a power conversion device, then each circuit can be optimized for its specific function, but the device size increases

Engineering Contradiction:
Improvecircuit optimizationVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges multiple circuits into a single integrated device, sharing semiconductor modules and other components. This consolidation reduces the overall device volume by eliminating redundant parts and optimizing space utilization through integrated design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By making semiconductor modules universal across multiple circuit functions, the patent reduces the total component count and device size. The same hardware serves multiple purposes, preventing the need for separate dedicated components that would increase overall volume.

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

3Device complexity

If the number of parts is reduced by integrating circuits, then downsizing is achieved, but reliability may deteriorate on routes where circuits are mixed

Engineering Contradiction:
Improvenumber of partsVSAvoidsystem reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent integrates circuits while maintaining functional independence through separate control logic. Each circuit (boosting, overvoltage suppression, brake chopper) can be controlled and monitored independently, ensuring reliability even though hardware components are shared.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control system is segmented into independent control units for each circuit function. This allows independent optimization and fault isolation, where a failure in one circuit's control logic does not necessarily affect the operation of other circuits, maintaining overall system reliability.

Inventive Principle:
Principle #1Segmentation

4Reliability

If various circuits are mixed in a power conversion device, then parts reduction is difficult, but improving reliability becomes challenging

Engineering Contradiction:
Improvefailure risk reductionVSAvoidcircuit integration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple circuits into a unified device structure, reducing the number of discrete parts and potential failure points. By sharing common components like semiconductor modules and housings, the overall failure risk is reduced despite the complexity of integrating multiple functions.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3745579B1Power conversion device and electric railroad vehicle equipped with power conversion device
Publication Date: 2025.06.25 HITACHI LTD
  • EP3745579B1 patent drawingFigure 1
  • EP3745579B1 patent drawingFigure 2
  • EP3745579B1 patent drawingFigure 3

AI summary

Provided is a power conversion device with which it is possible to achieve size reduction and improve reliability by reducing the number of components of a system as a whole. The power conversion device (100) comprises a semiconductor module (110) of a half-bridge configuration in which two semiconductor elements are arranged in series. The semiconductor module (110) has a substantially cuboidal shape and has, along a longitudinal direction of the cuboid, a positive pole terminal, a negative pole terminal, and terminals for inputting or outputting alternating current or for specific purposes, forming a single phase of the power conversion device (100). In the vertical direction corresponding to a widthwise direction of the cuboid, a plurality of the semiconductor modules (110) are arranged vertically, forming a plurality of phases of the power conversion device (100). The semiconductor modules (110) of the plurality of phases are installed in contact with a cooling unit (150), and one or more capacitors (120) are disposed so as to face the cooling unit (150) across the semiconductor modules (110) of the plurality of phases.