Solid-State Circuit Breaker NTC Sensing for Overheat Protection
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Solution Overview
Problem
Traditional mechanical circuit breakers are unable to meet the high requirements of modern power systems due to their slow response times and inability to effectively protect against short circuits and leakage, while existing solid-state circuit breakers lack efficient temperature data acquisition systems to monitor and control circuit health.
Innovation Solution
A solid-state circuit breaker equipped with NTC temperature data acquisition circuits to monitor the temperature of power supply terminals and switches, utilizing a voltage follower, V/F conversion circuit, isolator, and microcontroller to determine the contact state and control the circuit's on-off based on temperature data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional mechanical circuit breakers are used, then the device complexity is low, but the response speed is slow and they cannot meet high requirements of modern power systems
Solution Approach 1:
The patent replaces the mechanical switching mechanism with solid-state power electronic devices (IGBTs, MOSFETs) that use electronic control signals to switch circuits. This substitution eliminates mechanical wear and contact bounce, achieving response times in the microsecond range while maintaining system reliability through solid-state operation.
Solution Approach 2:
The patent implements dynamic control capabilities through microcontrollers and programmable logic controllers that can adjust switching parameters in real-time based on system conditions. The control system dynamically modifies pulse width modulation (PWM) parameters, switching frequencies, and protection thresholds to optimize performance under varying load conditions.
2Reliability
If solid-state circuit breakers are used, then the response speed is fast, but they lack efficient temperature data acquisition systems to monitor and control circuit health
Solution Approach 1:
The patent divides the temperature monitoring system into multiple independent sensing channels, each equipped with NTC thermistors positioned at critical locations (power supply terminals, switch components, heat-generating areas). This segmentation allows targeted monitoring of specific thermal zones without requiring a monolithic complex sensing system.
Solution Approach 2:
The patent introduces NTC thermistors as intermediary sensing elements that convert temperature information into resistance changes, which are then processed by voltage follower circuits and V/F conversion circuits. These intermediaries bridge the gap between thermal conditions and electronic control systems, enabling indirect but accurate temperature measurement.
3Measurement precision
If NTC temperature data acquisition circuits are installed, then temperature monitoring capability is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple circuit functions into integrated modules: the voltage follower circuit serves both as a buffer and signal conditioning element, the V/F conversion circuit integrates frequency modulation and isolation functions, and the isolator combines electrical isolation with signal transmission. This merging reduces the overall component count and simplifies the acquisition system architecture.
Solution Approach 2:
The patent designs the temperature acquisition circuit with multi-functional components that serve multiple purposes: the same NTC thermistor network monitors both power supply terminals and switch components, the voltage follower provides both signal buffering and impedance matching, and the isolator delivers both electrical isolation and signal conditioning in a single stage.
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 fast and reliable detection of abnormal temperature conditions in power supply terminals and switches, allowing for timely circuit control and protection against overheating and poor contact, ensuring safety and efficiency.
Implementation Method 1
Negative Temperature Coefficient (NTC) refers to thermistor phenomena and materials with negative temperature coefficient whose resistance decreases exponentially with the increase of temperature
Data Source
Figure 1~2
Figure 3~4
AI summary
The disclosure relates to a solid-state circuit breaker with negative temperature coefficient NTC temperature data acquisition, wherein the solid-state circuit breaker includes: a plurality of first NTC temperature data acquisition circuits, each connected with an input end and an output end of power supply terminals and configured to acquire a first resistance value indicating temperature data of the power supply terminals; a plurality of second NTC temperature data acquisition circuits, each connected to both ends of a switch and configured to acquire a second resistance value indicating temperature data of the switch; a voltage follower, configured to output a voltage value corresponding to the second resistance value; a voltage/frequency V/F conversion circuit, configured to output an amplitude-frequency converted voltage value; an isolator, configured to output a digitally isolated voltage value; and a microcontroller MCU, connected to the first NTC temperature data acquisition circuit and the isolator, and performs on-off of the switch based on the first resistance value and the digitally isolated voltage value.