DC Circuit Breaker Commutation Control for Fast Re-Closing
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Solution Overview
Problem
Conventional DC circuit breakers face challenges with high cost, large volume, and design contradictions when attempting to achieve fast re-closing functions due to slow charging times and increased complexity in commutation capacitor management.
Innovation Solution
A DC circuit breaker device with a commutation module comprising a commutation capacitor, switch module, and control module that allows for controlled charging and discharging to a predefined polarity and voltage, enabling efficient re-closing and disconnecting operations without the need for pre-charging or additional capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional DC circuit breakers implement fast re-closing functions with pre-charged commutation capacitors, then the re-closing speed is improved, but the device complexity and cost increase
Solution Approach 1:
The patent extracts the pre-charging function from the commutation capacitor management system. By using a separate charging resistor connected in parallel with the commutation capacitor, the charging operation is separated from the main commutation circuit, simplifying the control logic and reducing management complexity while maintaining fast re-closing capability
Solution Approach 2:
The patent applies preliminary action by pre-charging the commutation capacitor through a dedicated charging resistor before the re-closing operation. This ensures the capacitor is ready to provide the necessary commutation current immediately when re-closing is required, enabling fast re-closing without complex real-time charging control
2Speed
If multiple commutation capacitors are used to achieve fast re-closing, then the re-closing performance is improved, but the device volume and cost increase
Solution Approach 1:
The patent makes the single commutation capacitor multi-functional by equipping it with dual roles: (1) commutation function during normal breaking operations, and (2) fast re-closing function when charged through the charging resistor. This eliminates the need for separate capacitors for different functions, reducing device volume while maintaining performance
3Reliability
If conventional methods use additional capacitors for pre-charging, then the re-closing capability is improved, but the manufacturing cost and footprint increase
Solution Approach 1:
The patent merges the re-closing capability function into the existing commutation capacitor and charging resistor components. By combining the commutation and re-closing functions into a single integrated system rather than using separate components, the manufacturing cost and footprint are reduced while maintaining reliable re-closing capability
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 fast re-closing and disconnecting functions with a simple structure, low cost, and reduced footprint, effectively addressing the limitations of conventional methods by utilizing a single commutation capacitor for quick voltage and polarity adjustments.
Implementation Method 1
a commutation module connected in parallel with the first circuit breaker and comprising a commutation capacitor, a commutation switch module and a commutation inductor connected in series
Data Source
Figure 1
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Figure 3(a)~3(d)
AI summary
A DC circuit breaker device is provided, comprising: a circuit breaker module including a first circuit breaker and a second circuit breaker connected in series with the first circuit breaker for connecting a load and a DC power source in a DC circuit system; a commutation module connected in parallel with the first circuit breaker and comprising a commutation capacitor, a commutation switch module and a commutation inductor connected in series; the commutation switch module comprising a commutation switch positive branch and a commutation switch negative branch, the commutation switch positive branch and the commutation switch negative branch being capable of being controllably switched on/off; and a control module coupled to the circuit breaker module and the commutation module, and configured to control the switching on/off of the commutation switch positive branch and the commutation switch negative branch after the first circuit breaker is re-closed, so that the commutation capacitor is charged/discharged to a predefined polarity and voltage that satisfies a requirement for the first circuit breaker to disconnect again. A method of controlling a DC circuit breaker is also provided.