Railcar Power Conversion Circuit for Multi-Source Route Operation

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Solution Overview

Problem

Existing railroad-vehicle driving systems face issues with increased weight, reduced flexibility in train formation, higher maintenance costs, and reduced reliability due to the need for multiple power converters and apparatuses for different power sources, which are not efficiently shared between electrified and non-electrified routes.

Innovation Solution

Standardizing power conversion circuits to convert AC power from multiple AC power supplies to DC power, allowing for a downsized, lightweight, and simplified driving system that can handle various AC power supplies, reducing the number of components and increasing the freedom in train formation and maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple power converters are provided for different power sources (overhead contact line, power generator, fuel cells), then the railroad-vehicle can operate on both electrified and non-electrified routes, but the weight of the train formation increases

Engineering Contradiction:
Improveoperability on different routesVSAvoidweight of train formation
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent applies universality by designing a power converter that can handle multiple types of power sources (overhead contact line, power generator, fuel cells) with a single unified device. This eliminates the need for separate dedicated converters for each power source, thereby reducing the total number of components and the overall weight of the train formation while maintaining full operability across different route types.

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

Solution Approach 2:

The patent merges multiple separate power converter functions into a single integrated power converter unit. By combining the conversion capabilities for different power sources into one device, the system reduces component count and weight while maintaining the ability to operate on both electrified and non-electrified routes.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If multiple power converters and apparatuses are provided for different power sources, then the railroad-vehicle can operate on both electrified and non-electrified routes, but the maintenance cost increases

Engineering Contradiction:
Improveoperability on different routesVSAvoidmaintenance cost
Core Design Contradiction:
Adaptability or versatilityVSEase of repair

Solution Approach 1:

The unified power converter design reduces maintenance costs by eliminating the need to maintain multiple separate converter systems. A single standardized device with multi-functional capability requires fewer maintenance interventions, reduces spare parts inventory needs, and simplifies troubleshooting procedures compared to having separate dedicated converters for each power source.

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

Solution Approach 2:

By merging multiple converter functions into one system, the patent reduces the overall maintenance burden. Fewer components mean fewer potential failure points, reduced maintenance frequency, and lower cumulative maintenance costs over the vehicle's operational lifetime.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If multiple power converters and apparatuses are provided for different power sources, then the railroad-vehicle can operate on both electrified and non-electrified routes, but the reliability reduces due to increase in number of components

Engineering Contradiction:
Improveoperability on different routesVSAvoidsystem reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The unified power converter improves reliability by reducing the total number of components in the system. With fewer components, there are fewer potential failure points. The single standardized device also ensures consistent performance across different power sources, eliminating variability issues that could arise from having multiple different converter types.

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

Solution Approach 2:

By combining multiple converter functions into one integrated system, the patent reduces component count and interconnection complexity. This merging approach minimizes the number of potential failure points and simplifies the system architecture, thereby improving overall reliability while maintaining the ability to operate on different route types.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If multiple power converters and apparatuses are provided for different power sources, then the railroad-vehicle can operate on both electrified and non-electrified routes, but the freedom of train formation is reduced

Engineering Contradiction:
Improveoperability on different routesVSAvoidfreedom of train formation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The unified power converter enables greater freedom in train formation by providing a standardized, multi-functional power conversion solution that can be implemented across different vehicle types. This standardization allows for more flexible configuration options when composing train formations, as vehicles with the unified converter can be more easily integrated and combined in various arrangements.

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

Solution Approach 2:

By merging converter functions into a single standardized unit, the patent reduces the spatial and structural constraints associated with housing multiple separate converter systems. This consolidation provides more design flexibility in vehicle layout and enables greater freedom in how trains can be formed and configured for different operational requirements.

Inventive Principle:
Principle #5Merging (Combining)

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

This approach reduces the weight and maintenance costs of the multi-car train, enhances reliability, and increases the versatility of railroad-vehicles by allowing for more flexible train compositions and operations across electrified and non-electrified routes.

Implementation Method 1

power conversion circuits that convert AC power supplied from a plurality of AC power supplies to DC power

Methodology Applied
Scientific EffectPower conversion:

Data Source

PatentEP2671748B2Driving system, driving system for railroad-vehicle, and railroad-vehicle and multi-car train mounted with same
Publication Date: 2023.11.15 HITACHI LTD
  • EP2671748B2 patent drawingFigure 1
  • EP2671748B2 patent drawingFigure 2
  • EP2671748B2 patent drawingFigure 3

AI summary

A system corresponding to a plurality of different power sources (overhead contact line, power generator driven by engine, and fuel cells) is proposed as a method of using an optimum power supply in an electrified route and a non-electrified route. However, since different power converters are necessary for each power source, there are problems of an increase in the weight of a multi-car train, a reduction in the degree of freedom in composing a multi-car train because a mounting space needs to be reserved, an increase in the maintenance cost, a reduction in the reliability caused by an increase in the number of components, and the like. Provided are: a power conversion circuit that includes AC input ends, the number of which corresponds to the maximum number of phases among a plurality of different AC power supplies, and that converts AC power to a direct current; and switching means for switching a connection state of the AC power supplies and the power conversion circuit, wherein the connection state is switched according to the power supplies.