Low-Voltage Circuit Breaker With Temperature-Adaptive Trip Thresholds
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Solution Overview
Problem
Existing circuit-breaker devices for low-voltage circuits face challenges in securely interrupting current flux during overcurrent or short-circuit events, particularly due to thermal destruction risks for semiconductor-based switching elements, and require efficient methods to adapt current threshold values based on temperature levels without over-dimensioning the electronic interruption unit.
Innovation Solution
A circuit-breaker device with a mechanical break contact unit connected in series to an electronic interruption unit, featuring a current sensor and control unit that adjusts current threshold values according to the temperature level, allowing for secure interruption by switching semiconductor-based elements to high-resistance states, and utilizing a combination of analog and digital components for rapid threshold adaptation and comparison.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If semiconductor-based switching elements are used in the electronic interruption unit, then the circuit-breaker device achieves rapid current interruption capability, but the semiconductor elements are at risk of thermal destruction during overcurrent or short-circuit events
Solution Approach 1:
The patent implements dynamic adaptation of current threshold values based on real-time temperature measurements. The control unit continuously monitors temperature and adjusts the threshold values accordingly, making the protection characteristics adaptive rather than static. This resolves the contradiction by enabling rapid interruption when needed while preventing thermal destruction through temperature-dependent threshold adjustment.
Solution Approach 2:
The patent changes the parameter of current threshold values based on temperature conditions. By making the threshold values temperature-dependent, the system can maintain rapid response capability while adapting the protection level to current thermal conditions, thus preventing semiconductor thermal destruction during overcurrent events.
2Device complexity
If fixed current threshold values are used for short-circuit detection, then the control logic is simple, but the electronic interruption unit may be over-dimensioned or unable to respond optimally to different temperature conditions
Solution Approach 1:
The patent transitions from static fixed threshold values to dynamic temperature-adaptive threshold values. The control unit automatically adjusts thresholds based on temperature sensor input, providing adaptability to different operating conditions while maintaining relatively simple control logic through automated feedback adjustment.
Solution Approach 2:
The patent implements a feedback mechanism where temperature measurements are continuously fed back to the control unit, which then adjusts the current threshold values accordingly. This feedback loop enables automatic adaptation without complex manual configuration, resolving the contradiction between simplicity and adaptability.
3Reliability
If the current threshold value is reduced to prevent thermal destruction, then semiconductor safety is improved, but the breaking capacity of the circuit-breaker device is reduced
Solution Approach 1:
The patent uses dynamic threshold adjustment based on real-time temperature conditions rather than fixed reduced thresholds. This enables the system to maintain high breaking capacity when temperatures are low while providing thermal protection when temperatures are high, thus resolving the contradiction between protection and capacity.
Solution Approach 2:
The patent changes the current threshold parameter dynamically based on temperature conditions. By making the threshold temperature-dependent, the system can operate at high power levels when cool while automatically reducing thresholds to prevent thermal destruction when hot, eliminating the need for permanent capacity reduction.
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 secure and efficient interruption of current flux in low-voltage circuits by adapting current threshold values based on temperature, preventing thermal destruction and ensuring high economic capacity utilization, with rapid response times and flexible threshold adjustments.
Implementation Method 1
the electronic interruption unit, by means of semiconductor-based switching elements, is switchable to a high-resistance state of the switching elements, for the prevention of a current flux
Implementation Method 2
A bimetallic protection element or bimetallic element is customarily employed for tripping (interruption) in the event of a sustained overcurrent (overcurrent protection) or in the event of a thermal overload (overload protection)
Implementation Method 3
An electromagnetic trip element with a coil is employed for short-time tripping in the event of an overshoot of an overcurrent limiting value or in the event of a short-circuit (short-circuit protection)
Implementation Method 4
One or more arc-quenching chamber(s) or arc-quenching devices are provided
Implementation Method 5
In semiconductor-based circuit-breaker devices or protective devices, now described as solid state circuit-breakers, or SSCB for short, it is necessary for switching energy to be converted, not into an arc, as per a mechanical switching device, but into heat, by means of an additional circuit or energy absorber
Data Source
AI summary
A circuit breaker device for protecting a low-voltage electric circuit includes a mechanical break contact unit connected in series with an electronic interruption unit. The break contact unit is switchable by opening contacts to prevent current flow or by closing the contacts to allow current flow in the low-voltage circuit. The electronic interruption unit is switchable by semiconductor-based switching elements into a high-resistance state of the switching elements to prevent current flow or into a low-resistance state of the switching elements to allow current flow in the low-voltage circuit. The amplitude of the current in the low-voltage circuit is ascertained to provide instantaneous current values which are compared with at least one current threshold value, and if the threshold value is exceeded, prevention of current flowing in the low-voltage circuit is initiated. The at least one current threshold value is adjusted according to a temperature level of the circuit breaker device.