DC Link Control Device Optimizing Fuse Sizing via Energy Storage
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Solution Overview
Problem
Existing electrical switching arrangements are oversized and expensive due to the need for fuses to handle peak current demands, which are not continuously present, leading to inefficient dimensioning and increased costs.
Innovation Solution
An electrical control device that regulates energy flow between an intermediate circuit and an energy storage unit based on the effective current value, allowing for early detection of pulse-like current demands and optimizing fuse sizing by managing energy storage to equalize current draw from the supply network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuses are dimensioned for peak current demands to avoid damage, then reliability is improved, but device cost increases due to oversized components
Solution Approach 1:
The energy storage unit pre-stores electrical energy during periods of low current demand, so that when pulse-like peak currents occur, the stored energy can be discharged to support the intermediate circuit. This preliminary energy storage allows the fuse to be dimensioned for lower continuous current while still handling peak demands, resolving the contradiction between reliability and cost.
Solution Approach 2:
The energy storage unit acts as an intermediary between the supply network and the intermediate circuit. It decouples the continuous current draw from the intermittent peak demands, allowing the fuse to see only the averaged current profile rather than the full peak demands, thus enabling cost-effective dimensioning while maintaining protection.
2Reliability
If fuses are dimensioned for continuous peak current demands, then reliability is improved, but energy efficiency deteriorates due to oversized components operating below capacity
Solution Approach 1:
The energy storage unit continuously charges during low-demand periods, preparing energy in advance. This allows the system to meet peak demands without requiring the fuse and switching components to be continuously oversized, enabling them to operate near their optimal capacity and reducing energy losses from inefficient operation.
3Device complexity
If mean current intensity is used for dimensioning, then device complexity is reduced, but measurement precision deteriorates as pulse-like current demands cannot be detected
Solution Approach 1:
The energy storage unit serves as a mediator that physically responds to peak current demands by discharging stored energy. This tangible response allows the system to detect and handle pulse-like currents through the energy storage/discharge mechanism rather than requiring complex measurement systems, thus maintaining simplicity while improving detection capability.
Data Source
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AI summary
The invention relates to an electrical control device for optimizing the operation of a DC link. The control device can be connected to at least one line between a power supply network and the DC link on the one hand, and to at least one electrical energy storage unit on the other. The control device is designed to regulate the energy flow between the DC link and the at least one electrical energy storage unit as a function of an RMS current value between the power supply network and the DC link. The invention also relates to an electrical circuit with a DC link, wherein the circuit includes the control device according to the invention, and to an electrical switching arrangement with the electrical circuit according to the invention.