Hybrid Semiconductor Mechanical Switch for Current Cutoff
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Solution Overview
Problem
Existing semiconductor cutoff devices face issues with high energy dissipation due to semiconductor switches and are prone to electric arcs during transitional periods in mechanical switches, leading to reduced robustness and increased sensitivity to repeated opening and closing sequences.
Innovation Solution
A semiconductor cutoff device with a circuit configuration that includes a semiconductor switch in parallel with a mechanical switch, where the semiconductor switch is closed before the mechanical switch during the conductive state and opened after during the cut-off state, minimizing energy dissipation and preventing electric arcs by controlling the switching sequence to avoid the transitional rebound period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semiconductor switch is used in the cutoff device, then the device can provide reliable current interruption, but the energy dissipation becomes excessively high making the device impractical for industrial use
Solution Approach 1:
The invention divides the switch function into two separate switches: a semiconductor switch (first switch) and a mechanical switch (second switch). The semiconductor switch handles the high-reliability switching function, while the mechanical switch provides a low-resistance parallel path that carries most of the current during normal operation. This segmentation allows each switch to operate in its optimal regime, with the semiconductor switch dissipating minimal energy since it only carries control signals and leakage currents.
Solution Approach 2:
The invention combines two different switching technologies (semiconductor and mechanical) into a single hybrid system. The semiconductor switch and mechanical switch are connected in parallel, merging their advantages: the semiconductor switch provides fast, reliable, and precise control, while the mechanical switch provides extremely low on-resistance. This merging allows the system to achieve both high reliability and low energy dissipation simultaneously.
2Loss of energy
If a mechanical switch is used to replace the semiconductor switch, then energy dissipation is reduced, but electric arcs appear during the transitional rebound period damaging the contact surfaces
Solution Approach 1:
The invention uses the semiconductor switch to perform preliminary action by establishing or breaking the circuit before the mechanical switch operates. During closing, the semiconductor switch closes first to establish the circuit, then the mechanical switch closes to provide the low-resistance path. During opening, the semiconductor switch opens first to interrupt the current, then the mechanical switch opens. This preliminary action by the semiconductor switch prevents electric arcs during the mechanical switch's transitional rebound period.
Solution Approach 2:
The semiconductor switch acts as an intermediary that mediates the switching process between the power source and the mechanical switch. It controls the timing and sequence of operations, ensuring that the mechanical switch operates only when current flow is minimal or zero. This intermediary control prevents direct arcing across the mechanical switch contacts during the vulnerable rebound period.
3Adaptability or versatility
If the semiconductor switch operates during repeated opening and closing sequences, then the device remains functional, but the cumulative energy dissipation and thermal stress reduce the device lifespan
Solution Approach 1:
The current carrying function is segmented from the control function. The mechanical switch segment handles the bulk current flow during normal operation, while the semiconductor switch segment handles only control signals and minimal leakage currents. This segmentation ensures that the semiconductor switch does not accumulate significant thermal stress during repeated operations, extending the overall device lifespan while maintaining full operational capability.
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
This configuration reduces energy dissipation, prevents electric arcs, and enhances the robustness of the device by ensuring the semiconductor switch operates only during the transitional period, thereby extending the device's lifespan and reducing damage from repeated operations.
Implementation Method 1
a first branch having an energy absorbing member
Data Source
AI summary
A semiconductor current cutoff device, including a circuit having a first branch including an energy absorbing member and a second branch including a semiconductor switch, the semiconductor switch being connected in parallel with the first branch, a current measuring means for measuring the intensity of the electrical current at a connection terminal of the device, and an electronic control unit for controlling the semiconductor switch, programmed to control the opening of the semiconductor switch when the current intensity measured by the current measurement means reaches a predetermined value, the device then switching from a conductive state to a cutoff state, the circuit including a third branch including a mechanical switch, and the electrical control unit being programmed so that the semiconductor switch is closed before the mechanical switch.