Propulsion Control Device Merging Inverter and DC/DC Converter

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Solution Overview

Problem

Existing electric vehicle propulsion control devices are bulky, heavy, and costly due to the need for separate DC/DC converters and inverters for power conversion.

Innovation Solution

An electric vehicle propulsion control device that incorporates a power converting unit capable of operating as both an inverter and a DC/DC converter, using a switching unit and control unit to select the operation mode based on vehicle operation, eliminating the need for a separate DC/DC converter for charging the power storage device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate DC/DC converter and inverter are used for power conversion, then power conversion functions are reliable, but device complexity, size, and cost increase

Engineering Contradiction:

Improvepower conversion reliabilityVSAvoidnumber of power converting devices

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the DC/DC converter and inverter into a single power converting unit that can perform both functions. The control unit switches the connection configuration of the power converting unit between a DC/DC converter configuration (for charging the power storage device from the overhead wire) and an inverter configuration (for driving the motor). This merging eliminates the need for separate devices, reducing device complexity, size, and cost while maintaining reliable power conversion functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The power converting unit is designed as a universal device that can perform multiple functions: it can operate as a DC/DC converter to charge the power storage device from the overhead wire, and as an inverter to drive the motor. The switching unit and control unit enable the same hardware to adapt between different operational modes, making the system more compact and cost-effective while preserving all necessary power conversion capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate DC/DC converter and inverter are mounted, then power conversion functions are independent, but weight increases

Engineering Contradiction:

Improvepower conversion independenceVSAvoidweight of propulsion control device

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent merges the DC/DC converter and inverter into a single integrated power converting unit, eliminating redundant components and reducing the overall weight of the propulsion control device. The switching unit enables the same hardware to perform both functions sequentially, removing the need for separate heavy components while maintaining functional independence through proper switching control.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If separate DC/DC converter and inverter are used, then power conversion functions are distinct, but cost increases

Engineering Contradiction:

Improvepower conversion functionalityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines two separate power converting devices into one integrated unit, reducing the total component count and manufacturing cost. The switching unit and control unit enable the single power converting unit to perform both DC/DC conversion and inversion functions, eliminating the need to manufacture and assemble separate devices, thereby reducing overall system cost while maintaining full power conversion functionality.

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 configuration reduces the size, weight, and cost of the propulsion control device by integrating the power conversion functions, allowing for efficient power management between the overhead wire, power storage device, and motor.

Implementation Method 1

a power converting unit configured to convert a direct-current voltage supplied from an overhead wire into a direct-current voltage for charging the power storage device

Methodology Applied

Scientific EffectElectrical Energy Conversion:

Implementation Method 2

convert a direct-current voltage supplied from an overhead wire or the power storage device into an alternating-current voltage

Methodology Applied

Scientific EffectElectrical Energy Conversion:

Data Source

PatentEP2599656B1Electric vehicle propulsion control device, and railway vehicle system

Publication Date: 2019.12.18 MITSUBISHI ELECTRIC CORP

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AI summary

It is an object of the present invention to provide an electric vehicle propulsion control device including a power storage device 15. The electric vehicle propulsion control device 15 includes a switch 4 configured to perform opening and closing of a circuit between an overhead wire 2 and a power converting unit 8, a switch 16 configured to perform opening and closing of a circuit between the power converting unit 8 and a motor 17, a switching unit 11 configured to select a terminal on a side of the power converting unit 8 to which the switch 4 is connected or a terminal on a side of the power converting unit 8 to which the switch 16 is connected and connect the terminal to the power storage device 15, and a control unit 1 configured to control the power converting unit 8, the switch 4, the switch 16, and the switching unit 11 to switch a connection destination of the power converting unit 8 and cause the power converting unit 8 to operate as an inverter or a DC/DC converter according to an operation form of an electric vehicle.