Hybrid MEMS Semiconductor Switch Cell for Arc Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Microelectromechanical switching elements (MEMS) in low-voltage circuit breakers have limited dielectric strength and current carrying capacity, leading to overloading and reduced service life due to manufacturing tolerances and switching process fluctuations, resulting in contact sticking and arcing during switch-off processes.
Innovation Solution
A switching unit that integrates semiconductor switching elements in parallel with MEMS, where the semiconductor element takes over current flow during critical switch-on and switch-off processes to relieve MEMS contacts, minimizing voltage and current imbalances and preventing plasma formation, with a control circuit incorporating delay elements to manage switching times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large number of MEMS are arranged electrically in parallel to handle higher currents, then the current carrying capacity is improved, but the device complexity increases and manufacturing precision requirements worsen due to distribution imbalances
Solution Approach 1:
A semiconductor switching element is introduced as an intermediary component connected in parallel with the MEMS. This semiconductor element acts as a mediator that handles high current during switching transitions, allowing the MEMS to operate at lower currents during critical switch-off periods and thereby reducing the number of MEMS needed while maintaining overall current carrying capacity.
Solution Approach 2:
The invention changes the operational parameters of the MEMS by using a control circuit to temporarily reduce the current through MEMS during switching transitions. The semiconductor element absorbs the high current stress during these transient periods, allowing the MEMS to operate within safer current parameters and reducing the need for excessive parallel MEMS configurations.
2Ease of manufacture
If manufacturing tolerances and switching process fluctuations occur in MEMS, then the ease of manufacture is improved, but the reliability deteriorates due to unequal voltage and current distribution causing overloading
Solution Approach 1:
The control circuit monitors the switching state of MEMS and dynamically adjusts the operation of the semiconductor switching element accordingly. During switch-off transitions, the control circuit activates the semiconductor element to carry the current, providing feedback-based protection that compensates for manufacturing variations and prevents overloading of individual MEMS components.
Solution Approach 2:
The semiconductor switching element is positioned in parallel with the MEMS to provide beforehand cushioning protection. During critical switching transitions, the semiconductor element is activated to absorb current and voltage stress before it can damage the MEMS, preventing harmful effects before they occur despite manufacturing tolerances.
3Power
If MEMS are used for switching higher currents, then the power handling capability is improved, but the object-generated harmful factors worsen due to contact sticking and arcing during switch-off processes
Solution Approach 1:
The semiconductor switching element serves as an intermediary that handles the harmful switching arc and plasma formation during switch-off. When high current needs to be interrupted, the semiconductor element remains conductive and absorbs the arc energy, preventing direct contact sticking and arcing at the MEMS contacts while still enabling high power handling 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 significantly extends the service life of MEMS by preventing overloading and arcing, allowing for the practical use of MEMS in circuit breakers and enabling efficient handling of higher currents and voltages without thermal issues, thus enhancing the overall switching cell's longevity.
Implementation Method 1
the semiconductor switching element only has to carry the current for a very short time, i.e. for a few microseconds, in order to relieve the electromechanical contacts of the MEMS
Implementation Method 2
the control circuit is designed in such a way that, for a switch-off process of the switch cell, the semiconductor switching element is switched off after it has been switched off of the microelectromechanical switching element
Implementation Method 3
switching plasmas such as sparks or arcs can occur during the switch-off process... this eliminates transient unequal distributions of current and voltages that otherwise occur due to different contact resistances and voltage drops. In particular, this suppresses the formation of switching plasmas when switching on and off
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to a switch cell comprising a semiconductor switch element (6), a micro-electromechanical switch element (8) (MEMS), and an electronic actuation circuit (10), the semiconductor switch element (6) and the micro-electromechanical switch element (8) being connected in parallel and wherein, for a switchoff process (12) for the switch cell (2), the actuation circuit (10) is designed such that the semiconductor switch element (6) is switched off after switching off (9) the micro-electromechanical switch element (8).