Electronic Load Protection Circuit for Fast Overcurrent Switch-Off
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Solution Overview
Problem
Conventional overcurrent and overload protection devices for electrical loads, such as fuses and semiconductor switches, are slow to respond and can cause significant power loss and damage due to high current levels, especially in inductive loads, as they require high current amplitudes to trigger switch-off mechanisms.
Innovation Solution
An electronic load protection apparatus with an integrated overcurrent protection circuit and sensor component that generates a voltage drop corresponding to current rise speed, allowing for rapid switch-off within a short period (less than 1 msec) using a driver circuit, and an integrated overload protection circuit that continuously measures load current to determine overload states, enabling efficient protection against overcurrent and overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor switches are used for overcurrent protection, then the protection device can interrupt electrical current, but the switch-off period is relatively long and requires high current amplitudes to trigger, causing significant power loss and damage before interruption
Solution Approach 1:
The patent changes the triggering parameter from current amplitude (conventional) to voltage drop (innovative). The sensor component detects voltage drop across the semiconductor switch, which occurs at much lower current levels than conventional amplitude-based detection. This parameter change enables early detection and rapid switch-off, reducing the protection time while maintaining reliability.
Solution Approach 2:
The patent replaces conventional mechanical or simple electronic switching mechanisms with an electronic control system that uses a sensor component to detect voltage drop and a controller to trigger switch-off. This substitution enables much faster response times compared to conventional mechanical circuit breakers or simple thermal-magnetic trip mechanisms.
2Loss of energy
If conventional protection circuits wait for high current levels to trigger switch-off, then the switching component can be protected from immediate damage, but by that time the electrical current has already reached damaging amplitudes and caused significant power loss
Solution Approach 1:
The patent implements preliminary protection by detecting voltage drop across the semiconductor switch before the current reaches damaging amplitudes. The sensor component continuously monitors the voltage drop, and when it exceeds a threshold, the controller immediately triggers switch-off. This preliminary action prevents both excessive power loss and component damage by acting at the earliest possible moment.
Solution Approach 2:
The patent employs feedback through the sensor component that continuously monitors the voltage drop across the semiconductor switch and provides real-time information to the controller. This feedback mechanism enables dynamic adjustment and immediate response to changing current conditions, optimizing both energy loss prevention and component protection.
3Reliability
If fuses are used for overcurrent protection, then the load can be protected against excessive current, but fuses only melt at relatively high current amplitudes allowing much electrical energy to be transferred to the load before protection activates
Solution Approach 1:
The patent replaces the mechanical melting process of fuses with an electronic detection and control system. The sensor component detects voltage drop electronically, and the controller triggers switch-off of the semiconductor switch through electronic control signals. This substitution eliminates the delay inherent in thermal-magnetic fuse operation and achieves much faster protection activation.
Solution Approach 2:
The patent changes the detection parameter from current amplitude (which fuses respond to only at high levels) to voltage drop (which occurs at much lower current levels). This parameter change enables the protection system to activate at the earliest stage of overcurrent, significantly reducing both protection time and energy transfer to the load.
4Device complexity
If conventional protection devices require high current amplitudes to trigger, then the protection mechanism can be simpler, but the response time is slower and causes more damage before interruption occurs
Solution Approach 1:
The patent introduces a sensor component as an intermediary between the semiconductor switch and the controller. This sensor component measures the voltage drop across the switch and provides a standardized signal to the controller, which then triggers the switch-off. This intermediary simplifies the overall control logic while enabling much faster and more sensitive detection than direct current amplitude measurement would allow.
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 protection against overcurrent and overload, minimizing energy transfer to the load and preventing damage, with a switch-off period significantly faster than conventional methods, thus effectively safeguarding both the electrical load and protection apparatus components.
Implementation Method 1
having a sensor component connected in series with the power switch and adapted to generate directly a voltage drop corresponding to the current rise speed of the electrical load current
Data Source
AI summary
A load protection apparatus for protecting an electrical load connected to an output terminal of the load protection apparatus against overcurrent, includes an overcurrent protection circuit having a power switch through which the electrical load receives an electrical load current via the output terminal and having a sensor component connected in series with the power switch. The sensor component is adapted to directly generate a voltage drop corresponding to the current rise speed of the electrical load current flowing from an input terminal of the load control apparatus, via the sensor component and the power switch to the output terminal. The sensor component further includes a driver circuit adapted to detect an occurring overcurrent depending on the voltage drop generated by the sensor component and depending on a voltage drop along the power switch adapted to switch off said power switch upon detection of an overcurrent within a switch-off period.