Bidirectional Current Breaking Circuit with Segmented Branches
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Solution Overview
Problem
High-voltage DC circuit breakers face challenges in quickly isolating bidirectional faults while maintaining low power transmission losses and minimizing costs, as existing solutions either suffer from slow arc extinguishing times or increased power semiconductor device costs and complexity.
Innovation Solution
The apparatus includes a breaking current branch circuit with nonlinear resistors and bidirectional power semiconductor switches, combined with a bridge-type branch circuit, allowing for efficient bidirectional current breaking with reduced semiconductor device count and optimized device layout, using high-speed isolation switches and power semiconductor devices in series connections to achieve fast switching and low losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional high-voltage DC circuit breaker is used with AC circuit breaker and LC oscillation circuit, then the current can be broken in two directions with small loss, but the arc extinguishing time is relatively long (tens of milliseconds)
Solution Approach 1:
The circuit breaker is divided into multiple independent circuit breakers (first circuit breaker, second circuit breaker, third circuit breaker) that operate in parallel. Each circuit breaker handles one direction of current, allowing simultaneous operation without interference and achieving both low loss and fast response
Solution Approach 2:
The patent replaces the conventional mechanical AC circuit breaker with solid-state circuit breakers based on semiconductor devices. This substitution eliminates the need for mechanical arc extinguishing processes, achieving microsecond-scale switching speeds while maintaining low conduction losses through the semiconductor devices
2Loss of time
If solid-state circuit breaker with semiconductor devices is used, then the breaking speed is extremely high (microsecond-scaled), but the on-state voltage drop is great and power transmission loss is increased
Solution Approach 1:
The current path is segmented into multiple parallel branches, each containing semiconductor devices. By distributing the current across multiple parallel paths, the total conduction loss is reduced while each semiconductor device operates within optimal current ranges, maintaining fast switching performance
Solution Approach 2:
The patent combines multiple circuit breaker units with different characteristics (fast switching semiconductor-based breakers and low-loss parallel configurations) into a unified system. This merging allows the system to achieve both the fast breaking speed of semiconductor devices and the low power transmission loss of parallel current paths
3Adaptability or versatility
If power semiconductor devices are connected in anti-parallel or anti-series to break current in two directions, then bidirectional current breaking is achieved, but the number of devices is doubled and costs are increased considerably
Solution Approach 1:
The bidirectional current breaking function is segmented into three separate unidirectional circuit breakers operating in parallel. Each breaker handles one direction of current flow, eliminating the need for complex anti-parallel or anti-series connections. This segmentation reduces the total number of semiconductor devices required while maintaining full bidirectional capability
Solution Approach 2:
The parallel configuration of three circuit breakers creates a universal system that can handle current in both directions simultaneously or independently. Each breaker unit serves multiple functions: current limiting, fault isolation, and bidirectional protection, reducing overall system complexity despite the parallel architecture
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 solution enables rapid bidirectional current breaking with low on-state losses, reduced costs, and improved semiconductor device utilization, achieving breaking times of around 3 to 5 milliseconds with significantly lower total costs compared to previous solutions.
Implementation Method 1
one nonlinear resistor 13 being connected in parallel to at least two first power semiconductor devices 5 mutually connected in series
Implementation Method 2
After being opened, the AC circuit breaker generates an electric arc, the voltage of the electric arc resonates in the LC oscillation circuit
Implementation Method 3
the voltage of the electric arc resonates in the LC oscillation circuit
Data Source
AI summary
An apparatus for breaking a line bidirectional current and a control method therefore. The apparatus comprises a breaking current branch circuit and an on-state current branch circuit, the breaking current branch circuit comprises one nonlinear resistor being connected in parallel to one first power semiconductor device, or one nonlinear resistor being connected in parallel to at least two first power semiconductor devices mutually connected in series; and the on-state current branch circuit comprises at least one bidirectional power semiconductor switch being connected in series to at least one high-speed isolation switch. The apparatus also comprises a bridge-type branch circuit. An apparatus for breaking a line bidirectional current, thereby greatly reducing costs of the apparatus and reducing difficulty in device layout, mounting and wiring of the apparatus on the premise of ensuring a breaking speed that is quick enough and a low loss.