Current Rise Speed Sensing for Fast Overcurrent Switch Protection
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Solution Overview
Problem
Conventional overcurrent protection devices are slow to respond and inefficient, often causing damage to loads due to high energy transfer before intervention and requiring replacement of fuses or semiconductor switches, which can be damaged by power losses and voltage drops.
Innovation Solution
An apparatus with a sensor component generating a voltage drop based on current rise speed, coupled with a driver circuit that automatically switches off the power switch within a short period upon detecting overcurrent, using redundant protection mechanisms and current measurement units to protect loads from overload and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional protection circuits use semiconductor switches with voltage drop monitoring, then overcurrent protection is provided, but the switch-off period is long (microseconds to milliseconds) and high current levels are required to trigger switching
Solution Approach 1:
The patent replaces conventional voltage-drop-based electronic monitoring with a magnetic field-based sensor system. The sensor component detects changes in magnetic field strength caused by current rise, converting physical field changes into electrical signals that trigger immediate switch-off. This substitution of detection mechanism enables nanosecond to microsecond response times, dramatically reducing the switch-off period compared to conventional voltage monitoring methods.
Solution Approach 2:
The patent changes the detection parameter from voltage drop (conventional method) to magnetic field strength change (new method). By monitoring the rate of change of magnetic field (dB/dt) rather than voltage levels, the system can detect current rise much earlier in the transient process, enabling switch-off at much lower current amplitudes and with significantly reduced delay time.
2Reliability
If fuses are used for overcurrent protection, then load protection is provided, but protection occurs only at high current amplitudes causing excessive energy transfer and component damage
Solution Approach 1:
The patent implements preliminary detection by monitoring magnetic field changes that occur at the very beginning of current rise, before the current reaches high amplitudes. The sensor component detects dB/dt changes immediately when overcurrent starts, triggering switch-off at low current levels. This preliminary action prevents the excessive energy transfer that occurs with fuse-based protection, which only operates after current has already risen to dangerous levels.
Solution Approach 2:
The patent replaces the thermal-melting mechanism of fuses with a magnetic field detection and electronic switching system. The sensor component converts magnetic field changes into electrical signals that immediately trigger power switch cutoff. This substitution eliminates the inherent delay in fuse operation, enabling protection at much lower energy levels and preventing thermal damage to load components.
3Measurement precision
If conventional protection circuits operate, then overcurrent detection is provided, but high current levels are required to trigger the switching component
Solution Approach 1:
The patent changes the detection parameter from current amplitude (conventional method) to rate of change of magnetic field (new method). By monitoring dB/dt rather than current magnitude, the system detects the onset of overcurrent immediately when it begins, regardless of the absolute current level. This parameter change enables early detection and immediate trigger, eliminating the delay inherent in amplitude-threshold-based systems.
Solution Approach 2:
The patent replaces conventional current sensing methods with magnetic field-based detection. The sensor component measures changes in magnetic field strength caused by current flow, converting these physical changes into electrical signals. This substitution enables detection of current rise at its very beginning, providing immediate trigger capability without the delays associated with conventional voltage drop or current amplitude monitoring.
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 provides rapid and efficient protection of loads and power switches, minimizing energy transfer during overcurrent events and preventing damage, with switch-off times of less than 1 millisecond, significantly improving protection efficiency compared to conventional systems.
Implementation Method 1
a sensor component connected in series with said power switch and adapted to generate directly an electrical voltage drop corresponding to a current rise speed of the electrical current flowing via the sensor component and via the power switch to said load
Data Source
AI summary
An apparatus for switching and/or protection of a load connected to said apparatus, said apparatus (1) comprising: a power switch (5) through which the connected load receives an electrical current; a sensor component (4) connected in series with said power switch (5) and adapted to generate directly an electrical voltage drop corresponding to a current rise speed of the electrical current flowing via the sensor component (4) and via the power switch (5) to said load; and a driver circuit (6) adapted to detect an occurring overcurrent depending on a voltage drop generated by said sensor component (4) with or without a voltage drop along the power switch (5) and to switch off said power switch (5) upon detection of an overcurrent within a switch-off period to protect said power switch (5) and said load.