Hermetic DC Voltage Switch with Segmented Cooling Chamber
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Solution Overview
Problem
Hermetically encapsulated DC voltage switches for high-voltage on-board electrical systems face limitations in current levels and resistive/inductive time constants due to thermal capacity constraints, making it difficult to efficiently interrupt direct currents and quench switching arcs.
Innovation Solution
The DC voltage switch design includes a hermetically encapsulated housing with a cooling chamber, heat sinks, conical outlet and inlet openings, and a gas flow mechanism that directs the arc towards the housing walls, enhancing thermal energy discharge and arc quenching, while using hydrogen or nitrogen gas and ceramic materials for improved thermal conductivity and fire resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the length of arc columns is extended to interrupt direct currents, then the current interruption capability is improved, but the thermal capacity requirement increases and the device complexity increases
Solution Approach 1:
The housing is divided into a switching chamber and a cooling chamber separated by a partition wall. The switching chamber contains the contacts and arc quenching region, while the cooling chamber receives hot gas through outlet openings and cools it before returning through inlet openings. This segmentation allows the arc interruption function and thermal management function to be spatially separated, enabling extended arc columns for reliable current interruption while managing the increased thermal capacity requirements through a dedicated cooling system.
2Reliability
If power conversion per unit length is increased to quench switching arcs, then the arc quenching efficiency is improved, but the thermal capacity constraint becomes more severe
Solution Approach 1:
A gas flow mechanism is implemented using hydrogen or nitrogen gas flowing through the switching and cooling chambers. Outlet openings in the partition wall allow hot gas to flow from the switching chamber to the cooling chamber, where it is cooled and returned through inlet openings. This pneumatic/thermal system efficiently removes heat from the arc region, enabling high power conversion per unit length for effective arc quenching while managing the severe thermal capacity constraints through continuous gas cooling.
3Reliability
If hermetical encapsulation is used to protect the switching device, then the reliability is improved, but the thermal energy discharge capability is limited
Solution Approach 1:
The partition wall between the switching chamber and cooling chamber is equipped with outlet openings and inlet openings that enable controlled gas flow while maintaining hermetical encapsulation of the overall device. These openings allow thermal energy to be discharged from the switching chamber through the partition wall into the cooling chamber, where it can be dissipated. This approach maintains the protective hermetical seal while providing effective thermal energy discharge pathways through the strategically positioned openings.
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 design improves the disconnection behavior and thermal management of the DC voltage switch, effectively quenching arcs and increasing the thermal capacity, enabling reliable operation in high-voltage systems with DC voltages greater than 300 V.
Implementation Method 1
at least one heat sink which is thermally connected to at least one of the stationary contacts is arranged in the cooling chamber
Implementation Method 2
heat sinks, conical outlet and inlet openings, and a gas flow mechanism that directs the arc towards the housing walls, enhancing thermal energy discharge
Implementation Method 3
a cooling chamber which is separated from the switching chamber by means of a partition wall, wherein the partition wall has at least one outlet opening and one inlet opening
Implementation Method 4
using hydrogen or nitrogen gas and ceramic materials for improved thermal conductivity and fire resistance
Data Source
AI summary
A DC voltage switch for high-voltage on-board electrical systems having a housing, at least two stationary contacts, and a moving contact, wherein, in each case, a first contact region of the stationary contacts is routed out of the housing and, in each case, a second contact region of the stationary contacts is arranged in a switching chamber of the housing with the moving contact, wherein the housing is hermetically encapsulated, wherein a cooling chamber which is separated from the switching chamber by a partition wall is arranged above the switching chamber, wherein the partition wall has at least one outlet opening and at least one inlet opening.