AC Breaking Circuit Using Impedance Feedback for Fast Fault Isolation
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Solution Overview
Problem
Existing AC breaking circuits, such as fuses and circuit breakers, take a relatively long time to break alternating current, which can cause damage to electrical loads and the circuit itself, and do not effectively manage overcurrents or short circuits.
Innovation Solution
A circuit with a series configuration of controllable switches and an impedance network, controlled by a transistor network that uses voltage measurements from the impedance network to quickly detect and manage overcurrents and short circuits, allowing for rapid switching and minimizing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fuse or circuit breaker is used to break alternating current, then the current can be interrupted, but the breaking process takes relatively long time which may damage electrical loads and the circuit itself
Solution Approach 1:
The impedance network is connected in series with the controllable switch between the input and output. The impedance network limits the rate of change of current (di/dt) before the switch opens, preventing sudden current interruption that would cause voltage spikes and damage to electrical loads. This preliminary action of current limiting resolves the contradiction by enabling fast switching while protecting against damage.
2Reliability
If a fuse or circuit breaker is used to break alternating current, then the current can be interrupted, but the response time is slow which may allow overcurrent to cause damage
Solution Approach 1:
The patent replaces traditional mechanical circuit breakers or fuses with a controllable electronic switch (such as a transistor or thyristor) that can be rapidly activated by electrical signals. The transistor network detects overcurrent conditions and triggers the controllable switch to open within microseconds, dramatically reducing response time while improving reliability of protection.
3Adaptability or versatility
If traditional circuit breaking methods are used, then current interruption is achieved, but the circuit cannot effectively detect and respond to different current conditions (overcurrent, short circuit)
Solution Approach 1:
The impedance network is connected to provide feedback about the current conditions to the control circuit. By monitoring voltage drops across the impedance network, the system can detect different fault conditions (overcurrent, short circuit) and adjust the switching action accordingly. This feedback mechanism enables versatile detection while keeping the overall circuit structure relatively simple.
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 rapid and precise control of AC breaking, significantly reducing the risk of damage to loads and the circuit by quickly detecting and responding to overcurrents and short circuits, with the ability to detect both conditions and manage power consumption patterns.
Implementation Method 1
an impedance network (Z; 140) coupled between the first controllable switch (106) and the second controllable switch (108), wherein the impedance network (Z; 140) comprises a limiting/delay circuit coupled between the first controllable switch (106) and the second controllable switch (108)
Implementation Method 2
the transistor network (TN; 110) being arranged to control the first controllable switch (106) and the second controllable switch (108), so as to control the breaking of the alternating current (AC) provided to the at least one electrical load (200n), based on a value of at least one voltage (V1; V2) of at least one node of the impedance network (Z; 140)
Data Source
Figure 1~2
Figure 3a
Figure 3b
AI summary
The present invention relates to a circuit and an arrangement for breaking alternating current, the circuit comprising: an input arranged to receive an alternating current (AC); an output arranged to provide the alternating current (AC) to at least one electrical load; at least one controllable switch coupled between the input and the output; an impedance network (Z) coupled between the input and the output; and a transistor network (TN) comprising at least one transistor (TTN1; TTN2), the transistor network (TN) being arranged to control the at least one controllable switch, so as to control the breaking of the alternating current (AC) provided to the at least one electrical load, based on a value of at least one voltage (V1; V2) of at least one node of the impedance network (Z).