Hybrid DC Circuit Breaker With Self-Energy Capacitor Commutation
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Solution Overview
Problem
High-voltage DC circuit breakers have limited breaking capacity and high costs due to reliance on fully-controlled IGBT components, requiring complex energy supply systems and overvoltage isolation, which restricts flexibility and reliability.
Innovation Solution
A self-energy-acquiring hybrid DC circuit breaker design that connects a current-through branch, breaking branch, and ground branch in parallel, utilizing a capacitor for energy storage and IGCT components to enhance breaking capacity without additional energy supply systems, simplifying the design and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fully-controlled IGBT components are used in hybrid DC circuit breaker, then the breaking capacity is limited by the level of breaking current of a single component, but the device cost and complexity increase due to large number of components required
Solution Approach 1:
The patent divides the circuit breaker into two functional branches: a current-through branch with mechanical switch for high current conduction, and a breaking branch with fewer power electronic components for current interruption. This segmentation allows each branch to be optimized for its specific function, reducing the total number of IGBT components needed while maintaining high breaking capacity.
Solution Approach 2:
The patent introduces a commutation unit as an intermediary between the current-through branch and breaking branch. This commutation unit includes capacitors and switches that facilitate smooth current transfer from the mechanical switch to the breaking branch, enabling the mechanical switch to handle high currents without requiring the breaking branch to have equivalent current handling capability, thus reducing component count.
2Reliability
If fully-controlled IGBT components are arranged dispersedly at high potential, then reliable operation is ensured, but complex energy supply system and overvoltage isolation are required, increasing device occupation and cost
Solution Approach 1:
The patent merges the energy supply function into the breaking branch itself by using capacitors within the breaking branch for voltage clamping and energy storage. This eliminates the need for separate external energy supply systems and overvoltage isolation equipment, reducing device complexity and occupation while maintaining operational reliability through intrinsic protection mechanisms.
3Ease of operation
If hybrid DC circuit breaker is designed with traditional energy supply system, then the device can operate, but the overall cost and device occupation increase
Solution Approach 1:
The patent implements self-service by enabling the breaking branch to supply its own operating energy through integrated capacitors that store energy during normal operation and release it during breaking operations. This self-contained energy supply approach eliminates external power sources and reduces device complexity while maintaining full operational functionality.
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
The solution enables improved breaking current capacity and reduced costs by allowing fully-controlled components to withstand fault currents, with the capacitor-assisted design enhancing the breaking performance and reducing the overall device occupation.
Implementation Method 1
the DC circuit breaker may include a current-through branch, a breaking branch and a ground branch... the breaking branch may include a full-bridge circuit formed based on a diode series valve, and a breaking module branch... each of the at least one breaking module unit includes a respective Integrated Gate-Commutated Thyristor (IGCT) branch, a respective auxiliary cutoff branch and a respective energy consumption branch that are connected in parallel
Data Source
AI summary
Disclosed in the present application are a self-energy-taking hybrid direct-current circuit breaker and an application method therefor. In the self-energy-taking hybrid direct-current circuit breaker, a breaking branch is connected to a through-current branch in parallel, a first end of a grounding branch is connected to the breaking branch, and a second end of the grounding branch is grounded. When a direct-current system operates stably, the through-current branch conducts a steady-state running current of the direct-current system, and when the direct-current system breaks down, a self-energy-taking capacitor in the breaking branch assists a power electronic device in achieving the breaking of a fault current.