Back-to-Back Full-Bridge Converter for Wind Turbine Reverse Dragging
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Solution Overview
Problem
Traditional converters in reversing systems and wind turbines suffer from weak load-carrying capacity, necessitating additional equipment that increases cost and complexity.
Innovation Solution
A reversing system with a converter comprising a first and second full-bridge connected back-to-back through a DC link, allowing for a folded-in-half structure that enhances load-carrying capacity by doubling output current and torque, reducing the need for additional equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a traditional back-to-back two-way converter is used for reversing function, then the converter structure is simple, but the load-carrying capacity is weak and additional equipment is needed
Solution Approach 1:
The converter is divided into two independent full-bridge modules (first full-bridge and second full-bridge) connected back-to-back through a DC link. Each full-bridge can independently handle current, allowing the system to distribute load across multiple parallel current paths, thereby doubling the effective current capacity without requiring additional external equipment.
2Reliability
If additional equipment is added to enhance load-carrying capacity, then the reversing function can be improved, but the construction cost increases
Solution Approach 1:
Two full-bridge converters are merged into a single integrated back-to-back converter system sharing a common DC link and control unit. This consolidation achieves enhanced load-carrying capacity through internal parallel current paths while avoiding the need for separate additional equipment, thereby reducing construction costs and system complexity.
3Productivity
If the converter operates at high current to match motor requirements, then the output performance can be improved, but the rectifier side current capacity is exceeded
Solution Approach 1:
The current path is segmented into two independent full-bridge modules that can operate in parallel. Each full-bridge handles a portion of the total current, allowing the system to deliver high output current to the motor while distributing the rectifier current load across both modules, preventing any single module from exceeding its current capacity.
Data Source
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AI summary
The present disclosure provides reverse dragging systems and wind turbines, the reverse dragging system includes a converter including a first full-bridge (101), a second full-bridge (102) and a DC Link; when the converter of the reverse dragging system is for reverse dragging, the converter is configured as follows: the first full-bridge (101) and the second full-bridge (102) are electrically connected back-to-back through the DC Link; an AC port of the first full-bridge (101) is disconnected from an external AC power supply (2) and is electrically connected with an AC port of the second full-bridge (102); the DC Link is for electrical connection with an external DC power supply; and the AC port of the second full-bridge (102) functions as an output terminal (P2) of the reverse dragging system. The reverse dragging system of the present disclosure has strong load-carrying capacity and can provide stable output performance.