MEMS Switching Device for Arcless Current Interruption
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Solution Overview
Problem
Current switching devices, such as fuses and circuit breakers, are inadequate in responding quickly to short-circuit faults, leading to excessive let-through energy and potential damage, especially in poly-phase systems, and existing solid-state switches face issues with leakage current and heat generation.
Innovation Solution
A micro-electromechanical system (MEMS) switch integrated with control circuitry and Hybrid Arcless Limiting Technology (HALT) circuit, which enables fast and arc-less switching by minimizing parasitic inductance and using a balanced diode bridge and pulse circuit to suppress arcing, allowing for rapid transition between conducting and non-conducting states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuses are used for over-current protection, then selectivity and response consistency are improved, but the device must be replaced after operation and cannot be reset
Solution Approach 1:
The patent replaces traditional mechanical fuse elements with a MEMS switch that can be electrically actuated. The MEMS switch uses electrostatic forces to open contacts without mechanical moving parts in the traditional sense, allowing for electronic control and reset capability while maintaining fast response characteristics.
Solution Approach 2:
The patent changes the operational state of the switch from permanent (fuse) to reversible (MEMS). By using electrostatic actuation, the switch can be opened and closed multiple times by changing the electrical parameters (voltage application) rather than requiring physical replacement.
2Ease of operation
If circuit breakers are used for over-current protection, then reset convenience is improved, but response time increases due to mechanical inertia and electronic computation
Solution Approach 1:
The patent eliminates traditional mechanical trip mechanisms and electronic computation systems by using a MEMS switch that responds directly to electrostatic forces. This removes mechanical inertia and computational delays, achieving microsecond-level response times while maintaining reset capability through electrical actuation.
3Ease of operation
If electromechanical contactors are used for switching, then ease of operation is improved, but interrupting capacity is insufficient for fault currents
Solution Approach 1:
The patent segments the switching function into two parts: the MEMS switch handles normal switching operations with full interrupting capacity, while the parallel resistive path handles fault current limitation. This division allows each component to be optimized for its specific function.
Solution Approach 2:
The patent introduces a parallel resistive path as an intermediary element that works alongside the MEMS switch. During fault conditions, this resistive path limits the current while the MEMS switch opens to complete the interruption, providing both protection and switching capability.
4Reliability
If vacuum contactors are used for high power switching, then interrupting capacity is improved, but transient overvoltages are generated and visual inspection is difficult
Solution Approach 1:
The patent replaces vacuum contactor mechanical switching with electrostatically actuated MEMS switching. This eliminates the abrupt contact separation that causes transient overvoltages in vacuum contactors, while maintaining high interrupting capacity through the MEMS device's design.
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 MEMS switch with HALT circuitry provides rapid response times, reduces let-through energy during faults, and prevents arcing, enhancing safety and reliability in electrical distribution systems by effectively interrupting currents without causing damage.
Implementation Method 1
A micro-electromechanical system (MEMS) switch integrated with control circuitry and Hybrid Arcless Limiting Technology (HALT) circuit, which enables fast and arc-less switching
Implementation Method 2
control circuitry and a current path integrally arranged with the control circuitry. The current path includes a set of conduction interfaces and a micro electromechanical system (MEMS) switch disposed between the set of conduction interfaces
Implementation Method 3
enables fast and arc-less switching by minimizing parasitic inductance and using a balanced diode bridge and pulse circuit to suppress arcing
Data Source
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AI summary
A current control device is disclosed. The current control device includes control circuitry and a current path integrally arranged with the control circuitry. The current path includes a set of conduction interfaces and a micro electromechanical system (MEMS) switch disposed between the set of conduction interfaces. The set of conduction interfaces have geometry of a defined fuse terminal geometry and include a first interface disposed at one end of the current path and a second interface disposed at an opposite end of the current path. The MEMS switch is responsive to the control circuitry to facilitate the interruption of an electrical current passing through the current path.