Modular Multilevel Converter Optical Interface Circuit
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Solution Overview
Problem
The high cost and length of optical fiber connections between a central control device and submodules in modular multilevel converters, due to the need for multiple optical waveguides across significant distances, result in substantial expenses and complexity.
Innovation Solution
A modular multilevel converter design featuring a single optical communication link between the control device and an interface circuit, with each submodule connected via a separate, potentially bi-directional optical communication link, allowing for efficient message transmission and potential redundancy in optical fibers to ensure reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two optical waveguides are laid from the central control device to each submodule, then reliable bidirectional communication is achieved, but the cost and length of optical fibers increase substantially
Solution Approach 1:
The communication path is segmented into two parts: a shared optical waveguide from the control device to the communication node, and individual optical waveguides from the communication node to each submodule. This segmentation allows one waveguide to be shared by multiple submodules, reducing the total quantity of optical fibers while maintaining reliable bidirectional communication.
Solution Approach 2:
A passive communication node is introduced as an intermediary between the central control device and the submodules. This node receives optical signals from the control device and distributes them to multiple submodules, eliminating the need for separate optical waveguides from the control device to each submodule and significantly reducing optical fiber quantity.
2Adaptability or versatility
If optical fibers are laid over considerable distances (100 m and more) to reach submodules, then communication coverage is improved, but the cost and complexity of installation increase
Solution Approach 1:
The long optical fiber path is segmented into a shared portion from the control device to the communication node, and shorter individual portions from the node to each submodule. This reduces the overall installation complexity while maintaining coverage over considerable distances.
Solution Approach 2:
The passive communication node serves as an intermediary that is positioned closer to the submodules, reducing the distance and complexity of individual optical fiber connections while maintaining overall communication coverage through the shared waveguide infrastructure.
3Reliability
If a separate optical waveguide is laid from each submodule to the control device, then bidirectional message transmission is ensured, but the cost of optical fibers and their laying increases
Solution Approach 1:
Multiple optical communication paths are merged at the passive communication node. The node combines the shared optical waveguide from the control device with individual waveguides to each submodule, enabling bidirectional message transmission while reducing the total quantity of optical fibers through shared infrastructure.
Solution Approach 2:
The passive communication node acts as an intermediary that enables bidirectional message transmission between the control device and submodules without requiring separate dedicated waveguides for each direction to each submodule, thereby reducing optical fiber quantity while maintaining transmission reliability.
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 significantly reduces the length and cost of optical fibers required, while maintaining reliable communication between the control device and submodules, even over long distances, by using a centralized interface circuit to distribute and collect messages effectively.
Implementation Method 1
Messages are transmitted to the submodules using fiber optic cables
Data Source
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AI summary
The invention relates to a modular multilevel converter (1) comprising sub-modules (1_1 to 6_n), each of which includes at least two electronic switching elements (202, 206), an electrical energy store (210), two galvanic power terminals (212), and a optical communication terminal (230). The converter further comprises a control device (35) for the sub-modules. The control device (35) is connected to an electronic interface circuit (404) by means of a first optical communication link (402). The interface circuit (404) includes a plurality of sub-module interfaces (450, 452), each of which is optically connected to one of the sub-modules by means of an optical sub-module communication link (456, 461).