Temperature-Dependent Circuit Breaker Current Limiting
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Solution Overview
Problem
Circuit breakers in DC power systems face issues with self-heating and ambient temperature influences, leading to potentially harmful high temperatures and defects, which existing solutions address by oversizing or implementing current-temperature derating, limiting their operational flexibility and efficiency.
Innovation Solution
An electrical circuit breaker system with an input terminal, output terminals equipped with current and temperature measuring units, a computing unit, and a control unit that determines total current limits based on temperature, allowing for intelligent current distribution and prioritization to prevent overheating, ensuring continuous operation within safe parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If circuit breakers are operated side by side in modular systems, then the system can supply power to multiple loads through current division, but the ambient temperature increases due to cumulative self-heating from multiple devices
Solution Approach 1:
The system continuously monitors the ambient temperature and the current drawn by each output terminal. Based on the temperature feedback, the control unit dynamically adjusts the total current limit and selectively interrupts individual output terminals to maintain temperature within safe operating parameters while maximizing the number of active loads.
Solution Approach 2:
The system dynamically adapts the current distribution among output terminals based on real-time temperature conditions. The total current limit is not fixed but varies with temperature, allowing the system to optimize power distribution to multiple loads while preventing thermal runaway in modular configurations.
2Reliability
If circuit breakers are designed with fixed current limits to prevent overheating, then safety is improved, but operational flexibility is reduced due to current-temperature derating requirements
Solution Approach 1:
The system replaces fixed current limits with dynamic, temperature-dependent current limits. The control unit continuously adjusts the total current limit based on the monitored ambient temperature, allowing the circuit breaker to operate at higher currents when cool and automatically reduce the limit when temperature rises, eliminating the need for conservative derating while maintaining safety.
Solution Approach 2:
The system changes the operating parameter (total current limit) as a function of temperature. Instead of using a fixed derated current value, the system continuously adjusts the current limit parameter based on real-time temperature measurements, enabling the circuit breaker to adapt to varying thermal conditions and maximize operational capacity within safe limits.
3Productivity
If the total current limit is increased to maximize power delivery, then productivity is improved, but the risk of harmful self-heating and defects increases
Solution Approach 1:
The system uses temperature feedback to dynamically control the total current limit. When the ambient temperature is low, the system allows higher current delivery to maximize productivity. When temperature rises indicating self-heating, the system automatically reduces the current limit to prevent harmful thermal effects, thus resolving the contradiction between power delivery and thermal safety.
Solution Approach 2:
The system monitors its own thermal state through temperature sensing and automatically adjusts its current delivery capacity accordingly. The circuit breaker system serves itself by detecting its thermal condition and making real-time adjustments to the total current limit, eliminating the need for external derating calculations or conservative fixed limits.
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 system effectively prevents continuous overheating by dynamically adjusting current distribution based on temperature, ensuring the circuit breaker operates within safe limits, protecting both the system and individual loads from overload while maintaining flexibility in application scenarios.
Implementation Method 1
Each output terminal includes an electrical switch for interrupting a current supply and a current measuring unit for measuring an individual current magnitude
Implementation Method 2
Each output terminal includes an electrical switch for interrupting a current supply and a current measuring unit for measuring an individual current magnitude
Implementation Method 3
The temperature acquiring unit is configured to acquire a temperature. The computing unit is configured to determine a total current limit as a function of the sensed temperature
Implementation Method 4
the currents flowing through a circuit breaker during normal operation lead to power loss and corresponding self-heating of the circuit breaker, in particular the electrical switch
Data Source
AI summary
An electrical circuit breaker system including an input terminal connecting an electrical current source and a plurality of output terminals for connecting electrical loads. Each output terminal includes an electrical switch and a current measuring unit. The circuit breaker system includes a current acquiring unit for acquiring current magnitudes measured at the output terminals and for determining a total current magnitude. A temperature acquiring unit acquires a temperature, and a computing unit is configured to determine a total current limit as a function of the acquired temperature. Further, a control unit is configured to select one of the plurality of output terminals based on a ranking of the output terminals and to interrupt the current supply at the selected output terminal by means of the corresponding electrical switch when the total current magnitude exceeds the determined total current limit.