Dual DC-Link Circuit Layout for Electric Construction Machines
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Solution Overview
Problem
Existing electrically operated construction machinery faces inefficiencies due to high energy demands and the need for a single central DC link, which complicates energy distribution and requires additional converters, limiting flexibility and reliability, especially in environments where a power connection is unavailable.
Innovation Solution
The implementation of a circuit arrangement with two intermediate circuits, each operating at different voltage levels, allowing for flexible and efficient energy distribution by connecting load units to the appropriate DC link, eliminating the need for additional converters and enabling operation without a power grid connection through a battery pack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single central DC link is used for energy distribution, then the electrical system structure is simplified, but additional converters are required and flexibility is limited
Solution Approach 1:
The patent divides the single central DC link into multiple intermediate circuits (first intermediate circuit and second intermediate circuit), each operating at different voltage levels. This segmentation allows different load units to be connected to appropriate voltage levels without requiring additional converters, thereby reducing system complexity while improving energy distribution flexibility and adaptability.
2Adaptability or versatility
If additional converters are used for voltage matching, then voltage compatibility is improved, but device complexity and cost increase
Solution Approach 1:
The patent assigns different voltage levels to different intermediate circuits based on the specific requirements of load units. Each intermediate circuit is designed with a voltage level optimized for its connected loads, eliminating the need for voltage conversion. This local optimization approach maintains voltage compatibility while avoiding the complexity and cost of additional converters.
3Use of energy by moving object
If a power grid connection is required for operation, then energy supply is sufficient, but operational flexibility and reliability are reduced
Solution Approach 1:
The patent designs the circuit arrangement to support multiple power sources: it can operate connected to the power grid for sufficient energy supply, or switch to battery power when disconnected. The intermediate circuits are configured to handle both grid power and battery power inputs, enabling the construction machine to maintain operational flexibility and reliability across different working conditions without requiring constant grid connection.
Data Source
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AI summary
The invention relates to an electrically operated civil engineering machine with a mobile carrier device, at least one electrical consumption unit, at least one internal rechargeable battery unit for storing and supplying electrical energy, at least one supply device for supplying electrical energy from an external energy source, and a circuit arrangement for supplying and discharging electrical energy to and from the at least one electrical consumption unit as required, wherein the circuit arrangement is configured to distribute electrical energy between the at least one electrical consumption unit and the supply device by means of an intermediate circuit.According to the invention, the circuit arrangement comprises a first intermediate circuit and a second intermediate circuit, the first intermediate circuit can be operated with a first voltage level, and the second intermediate circuit can be operated with a second voltage level, which is different from the first voltage level.