Low-Voltage Circuit Breaker Using Phase-Angle Voltage Detection
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Solution Overview
Problem
Existing circuit breaker devices for low-voltage AC circuits face challenges in quickly recognizing short circuits and ensuring reliable interruption, often requiring current sensors and complex deactivation processes.
Innovation Solution
A circuit breaker device with a voltage sensor and electronic interruption unit using semiconductor-based switching elements, where instantaneous threshold values are compared with phase-angle-related voltage values to initiate interruptions, allowing for quick short-circuit recognition and avoidance without the need for current sensors, and incorporating a mechanical isolating contact system for galvanic isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If semiconductor-based switching elements are used for interruption, then the deactivation energy is converted into heat requiring an energy absorber, but the current flowing at deactivation must be as low as possible which delays short-circuit recognition
Solution Approach 1:
Instead of detecting short circuits through current (the conventional approach), the patent inverts the detection method by monitoring voltage. The voltage sensor detects voltage dips or deviations from expected values, which indicate short circuits, allowing recognition without waiting for current to rise to dangerous levels.
Solution Approach 2:
The patent performs preliminary detection of short circuits by monitoring voltage before the current reaches harmful levels. By detecting voltage anomalies early, the system can initiate interruption before the short-circuit current becomes excessively high, preventing energy overload while maintaining fast response.
2Loss of time
If voltage sensor and phase-angle-related threshold comparison are used, then short-circuit recognition is accelerated, but the device complexity increases due to electronic components
Solution Approach 1:
The voltage sensor serves multiple functions: it monitors voltage levels for short-circuit detection, provides phase-angle information for timing the interruption, and enables the control unit to determine when voltage thresholds are exceeded. This multi-functionality reduces the need for separate dedicated components.
Solution Approach 2:
The patent replaces traditional mechanical short-circuit detection mechanisms (such as bimetallic strips or electromagnetic relays) with an electronic system using voltage sensors and digital threshold comparison. This substitution enables faster response times while the electronic components integrate into the existing circuit breaker structure.
3Reliability
If interruption is initiated when instantaneous threshold values are exceeded, then short-circuit protection is improved, but the risk of false tripping increases under normal voltage variations
Solution Approach 1:
The patent uses dynamic threshold values that vary with the phase angle of the AC voltage cycle. Instead of a fixed threshold, the threshold is adjusted based on the expected voltage at each phase angle, allowing the system to accommodate normal voltage variations while still detecting abnormal dips caused by short circuits.
Solution Approach 2:
The control unit continuously compares the actual voltage values with the phase-angle-related threshold values and adjusts the interruption decision based on this feedback. The system monitors whether threshold exceedances are transient or sustained, and whether they occur at expected phase angles, reducing false tripping while maintaining reliable short-circuit detection.
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
Enables rapid and reliable short-circuit detection and interruption in low-voltage AC circuits, reducing the loading of energy absorbers and preventing high currents, while providing galvanic isolation and enhanced protection functions.
Implementation Method 1
a voltage sensor (SU) for ascertaining the level of the voltage of the low-voltage circuit such that instantaneous/phase angle-related voltage values (DU) are available
Implementation Method 2
the switching energy does not, like in the case of a mechanical switching device, have to be converted into an arc, but rather converted into heat by way of an additional circuit, the energy absorber
Implementation Method 3
Circuit breaker devices having an electronic interruption unit often also have a mechanical isolating contact system, in particular having isolator properties in accordance with relevant standards for low-voltage circuits
Data Source
AI summary
A circuit breaker device for protection of an electrical low-voltage circuit determines the voltage level of the low-voltage circuit in such a way that current voltage values are provided and current threshold values are provided. The current voltage values are compared with the current threshold values in terms of phase angle in such a way that when the current threshold values are exceeded or undershot or a differential voltage value is formed from the current threshold value and the current voltage value, the differential voltage value is compared with a differential voltage threshold value and when it is exceeded or undershot, an interruption of the low-voltage circuit is initiated in order to avoid a short-circuit current. A method for protecting an electrical low-voltage circuit is also provided.