Self-Powered Electronic Fuse With Low-Current Capacitor Charging
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Solution Overview
Problem
Conventional electronic fuses are either destroyed when they trip, requiring replacement, which can be costly, and there is a need for an improved fuse that can be reset and reused without disrupting the electrical circuit.
Innovation Solution
A self-powered electronic fuse device with two externally accessible terminals, utilizing a storage capacitor and switch control circuitry that allows the fuse to conduct AC current and charge the capacitor during low current periods, tripping only under overload conditions to minimize disruption to the AC load current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuse is of the type that is destroyed when it blows or trips, then the fuse provides reliable protection, but the blown fuse must be removed and replaced with a new fuse, which is costly and time-consuming
Solution Approach 1:
The electronic fuse performs self-diagnosis and self-reset functions. The control circuit automatically detects overload conditions, opens the circuit, and can be reset without replacement, eliminating the need for manual intervention and reducing maintenance costs.
Solution Approach 2:
The patent replaces the traditional mechanical fuse (which melts and must be replaced) with an electronic system using solid-state switches, control circuits, and microprocessors that can detect and respond to overload conditions electronically, enabling reset and reuse.
2Power
If the storage capacitor charges during high current periods, then the capacitor charges faster, but it causes substantial interruption to the load current
Solution Approach 1:
The control circuit periodically monitors the current and selectively charges the capacitor during low-current intervals rather than continuously. This periodic charging approach ensures the capacitor accumulates sufficient energy while minimizing disruption to the load current flow.
Solution Approach 2:
The capacitor is charged in advance during low-current periods so that sufficient energy is stored before high-current demand occurs. This preliminary charging ensures the fuse can operate reliably during overload conditions without interrupting normal load current.
3Quantity of substance
If the fuse opens during high current flow to charge the capacitor, then the capacitor charges adequately, but it causes substantial disturbance to the AC load current
Solution Approach 1:
The system employs periodic monitoring and selective capacitor charging during low-current intervals, ensuring adequate charge accumulation while avoiding substantial disturbance to the AC load current during high-current flow periods.
4Ease of repair
If the electronic fuse uses complex control circuitry to enable resetting, then the fuse can be reused, but the device complexity increases
Solution Approach 1:
The control circuit automatically performs diagnosis and reset functions without requiring external intervention or complex manual procedures, simplifying the user interface while maintaining sophisticated internal control capabilities.
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 the fuse to be reset and reused, reducing replacement costs while minimizing disturbance to the AC load current, as it only opens during overload conditions, maintaining low resistance in normal conditions and efficiently managing capacitor charging to ensure reliable operation.
Implementation Method 1
a storage capacitor and switch control circuitry that allows the fuse to conduct AC current and charge the capacitor during low current periods
Data Source
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AI summary
A two-terminal electronic fuse device involves two switches, four diodes, switch control circuitry, and a storage capacitor, connected in a particular topology. When AC current flows through the fuse, a charging current charges the storage capacitor. Energy stored in the storage capacitor is then used to power the switch control circuitry. If the voltage on the storage capacitor drops, then the switches are opened briefly and at the correct time. Opening the switches allows the charging current to flow. By opening the switches and charging the storage capacitor only at times of low current flow through the fuse, the disturbance of load current flowing through the fuse is minimized. If an overload current condition is detected, then the fuse has tripped and first and second switches are opened. If the capacitor does not need charging and there is no overload condition, then the switches remain closed.