Power Conversion Relay Device for Fast Stop Command Transmission
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Solution Overview
Problem
Existing power conversion devices, such as Modular Multilevel Converters, face challenges in quickly transmitting stop commands to submodules during overcurrent events to prevent circuit failure, as existing communication methods do not efficiently prioritize the transmission of stop commands.
Innovation Solution
The implementation of a power conversion device with relay devices that utilize separate communication channels for stop commands and other information, where the communication speed of the channel used for stop commands is higher than that of other information, ensuring rapid transmission of stop commands to submodules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common command is transmitted through a single communication channel to all submodules, then the communication system is simple, but the transmission delay increases and protection response is slow
Solution Approach 1:
The communication system is segmented into multiple independent channels: a first communication channel dedicated to protection commands (stop commands) and a second communication channel for control commands. This segmentation allows protection commands to be transmitted independently without being delayed by control command traffic, thereby improving protection response speed while maintaining manageable system complexity through structured channel division.
Solution Approach 2:
Relay devices are introduced as intermediary components between the control device and submodules. These relay devices receive protection commands from the control device and forward them to the appropriate submodules through the first communication channel, enabling rapid protection response while distributing the communication load and reducing the complexity at any single point in the system.
2Speed
If control commands and protection commands are transmitted through the same communication channel, then the communication infrastructure is simplified, but the transmission speed of protection commands is reduced
Solution Approach 1:
The communication infrastructure is divided into two separate channels: the first communication channel exclusively for protection commands requiring high transmission speed, and the second communication channel for control commands. This segmentation ensures that protection commands are transmitted with maximum speed without being delayed by control command traffic, while the overall infrastructure complexity is managed through clear channel definition and dedicated usage.
3Loss of time
If a centralized control device transmits commands to all submodules directly, then the control structure is simple, but the communication transmission delay increases
Solution Approach 1:
Relay devices serve as intermediary components between the centralized control device and submodules. The control device transmits protection commands to relay devices through the first communication channel, which then forward these commands to submodules. This intermediary structure reduces communication transmission delay by distributing the command distribution function and enabling parallel transmission paths, while maintaining a manageable control structure through clear hierarchical relationships.
Solution Approach 2:
The control structure is segmented into control devices and relay devices with distinct functional responsibilities. Control devices generate protection commands and transmit them through the first communication channel to relay devices, which then distribute these commands to submodules. This segmentation enables more efficient command transmission by distributing the communication load and reducing the transmission delay that would occur in a purely direct centralized-to-submodule transmission model.
Data Source
AI summary
A power conversion device includes: power conversion circuitry including a plurality of submodules connected in series to each other; a protection device generating a protection command for protecting each submodule; and one or more relay devices outputting the protection command to each submodule. The relay device includes: a first communication circuit for communicating with the protection device; and a second communication circuit for communicating with the power conversion circuitry. The first communication circuit transmits the stop command to the second communication circuit through a first communication channel, and transmits different information different from the stop command to the second communication circuit through a second communication channel. The communication speed of communication through the first communication channel is higher than that of communication through the second communication channel.