AC Breaking Circuit With Auxiliary Branch for Fast Fault Isolation

Solution Overview

Problem

Conventional circuit breakers struggle to rapidly and reliably cut off high short-circuit currents, leading to potential safety hazards and increased component size and cost, especially in alternating current systems.

Innovation Solution

A breaking circuit with a main circuit and an auxiliary branch, including mechanical switches and a current-limiting circuit switch, controlled by a unit to divert and extinguish short-circuit currents, allowing rapid mechanical isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional circuit breaker is used to cut off high short-circuit current, then the circuit can be protected, but the breaking action has large component size, high costs, and long delay

Engineering Contradiction:

Improvefaulty current cutting capabilityVSAvoidbreaking action delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The breaking circuit is divided into a main circuit and an auxiliary branch. The main circuit includes a first mechanical switch for normal operation, while the auxiliary branch includes a second mechanical switch, overcurrent breaking switch, and current-limiting circuit switch for fault protection. This segmentation allows each part to be optimized for its specific function, enabling rapid faulty current cutting without requiring the entire circuit breaker to be oversized.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The control unit acts as an intermediary that receives information about current or voltage in the main circuit and sends control signals to the switches. This intermediary control mechanism enables rapid detection and response to short-circuit faults, reducing the breaking action delay by automatically triggering the auxiliary branch when faults are detected.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a circuit breaker with high current cutting capability is used, then faulty current can be cut off, but the component size becomes large and costs increase

Engineering Contradiction:

Improvehigh current cutting capabilityVSAvoidcircuit breaker size

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The breaking circuit is divided into a main circuit and an auxiliary branch. The main circuit includes a first mechanical switch for normal operation, while the auxiliary branch includes a second mechanical switch, overcurrent breaking switch, and current-limiting circuit switch for fault protection. This segmentation allows each part to be optimized for its specific function, enabling rapid faulty current cutting without requiring the entire circuit breaker to be oversized.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The auxiliary branch is designed to handle the excessive short-circuit current temporarily by providing a dedicated path with appropriate switching devices. The overcurrent breaking switch and current-limiting circuit switch in the auxiliary branch are specifically sized for fault conditions, allowing the main circuit components to remain smaller while still providing high current cutting capability when needed.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If a conventional circuit breaker is used for protection, then the circuit can be protected, but surrounding components may be damaged and implementation is complex

Engineering Contradiction:

Improvecircuit protection capabilityVSAvoidbreaking circuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The breaking circuit is divided into a main circuit and an auxiliary branch. The main circuit includes a first mechanical switch for normal operation, while the auxiliary branch includes a second mechanical switch, overcurrent breaking switch, and current-limiting circuit switch for fault protection. This segmentation allows each part to be optimized for its specific function, enabling rapid faulty current cutting without requiring the entire circuit breaker to be oversized.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The auxiliary branch serves multiple functions: it provides a dedicated path for short-circuit current, houses the overcurrent breaking switch for rapid fault interruption, and includes the current-limiting circuit switch to protect surrounding components. This multi-functionality reduces the need for separate protection devices, simplifying the overall implementation while maintaining comprehensive protection capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4657686A1Power conversion apparatus

Publication Date: 2025.12.03 HUAWEI DIGITAL POWER TECH CO LTD

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AI summary

This application provides a power conversion apparatus. The power conversion apparatus includes a breaking circuit and a control unit, and the breaking circuit includes a main circuit and an auxiliary branch. The main circuit is connected in parallel to the auxiliary branch, and the control unit is configured to control switch devices of the main circuit and the auxiliary branch to be turned on or turned off. The breaking circuit may be configured to protect an alternating current circuit including a mechanical breaking device. When a short-circuit fault occurs in the alternating current circuit, the breaking circuit can rapidly cut off a short-circuit faulty current, to implement mechanical isolation at a point of interruption for the fault. This application can reduce costs of a circuit breaker device in a system, a volume of the circuit breaker device, and an amplitude of a faulty current, shorten duration of a short-circuit current existing after a short-circuit fault occurs, and improve reliability of system fault breaking protection.