Electronic Overcurrent Switching for Inductive Load Protection
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Solution Overview
Problem
Conventional overcurrent protection systems for electrical loads, such as electrical motors, are slow to respond and inefficient, often causing damage due to high power losses and requiring replacement of fuses after an overcurrent event, while existing solutions struggle to provide effective protection for inductive loads.
Innovation Solution
A load control apparatus with an overcurrent protection circuit that includes a current rise speed sensor and a driver circuit capable of switching off the power switch within a short period (2 microseconds to 1 millisecond) when a configurable threshold voltage is exceeded, combined with an overload protection circuit that continuously measures load current to determine overload states and control power supply based on load and supply voltage profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional overcurrent protection systems are used, then the system structure is simple, but the response speed is slow causing damage to electrical loads
Solution Approach 1:
The control unit continuously monitors the electrical current and calculates its integral value in advance, so that when an overcurrent condition occurs, the protection can be triggered immediately based on pre-calculated data, eliminating the delay of conventional detection methods
Solution Approach 2:
The patent replaces mechanical fuses and electromechanical circuit breakers with an electronic control system that uses a control unit, driver circuit, and power switch, achieving much faster response speeds through electronic detection and control
2Reliability
If fuses are used for overcurrent protection, then the device complexity is low, but the protection is ineffective as fuses only melt at high current amplitudes allowing excessive energy transfer
Solution Approach 1:
The control unit continuously monitors the electrical current flowing to the load and calculates its integral value, providing real-time feedback to determine when overcurrent conditions occur, enabling dynamic adjustment and immediate protection
Solution Approach 2:
The patent changes the protection parameter from simple current threshold detection to integral current calculation, allowing the system to detect overcurrent conditions at lower current amplitudes by accumulating the effect over time, thus providing more effective protection
3Loss of time
If conventional protection devices are used, then the system is simple to implement, but the switch-off period is long requiring replacement of fuses after overcurrent events
Solution Approach 1:
The protection system automatically detects overcurrent conditions, triggers the driver circuit to switch off the power switch, and can automatically reset without requiring manual intervention or component replacement, providing self-service protection
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 against overcurrent and overload conditions, minimizing damage to electrical loads and components, and allowing for quick recovery and reuse of the power switch after an event, significantly improving the safety and reliability of electrical systems.
Implementation Method 1
a current rise speed sensor component (4) connected in series with the power switch (5) and adapted to generate directly a voltage drop corresponding to a current rise speed of the electrical load current
Data Source
AI summary
A load control apparatus for controlling a power supply to an electrical load connected to an output terminal includes an overcurrent protection circuit having a power switch through which the electrical load receives a load current and a sensor component in series with the power switch that is configured to generate a voltage drop corresponding to the current rise speed of a load current from an input terminal to the output terminal. The protection circuit includes a driver circuit configured to detect an overcurrent depending on the voltage drop generated by the sensor component and/or at the power switch, and to switch off the power switch upon detection of an overcurrent within a switch-off period. The overcurrent protection circuit can include a power supply control circuit having a sensor component adapted to measure a supply voltage notified to a control unit of the load control apparatus adapted to control power supplied to the load.