DC Switch Linkage for Stuck Contact Separation in Inverters
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Solution Overview
Problem
Inverters used in photovoltaic systems face reliability issues due to aging contacts and increased friction between movable and stationary contacts, leading to unreliable switch-off during faults like overcurrent or short circuits, especially under harsh outdoor conditions.
Innovation Solution
A direct current switch with an operating mechanism featuring a handle, input and output shafts, and a connecting rod assembly, including stacked sub-switches, which provides enhanced driving force to separate contacts even with rust or adhesion, and incorporates a trip-free function for reliable switch-off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the inverter operates for a prolonged service life under harsh outdoor conditions, then the inverter continues to provide power conversion functionality, but the contact surface between movable contact and stationary contact inevitably ages, leading to increased friction and rust
Solution Approach 1:
The patent divides the switch mechanism into multiple independent components: handle, input shaft, connecting rod assembly, output shaft, movable contact, and stationary contact. This segmentation allows each component to be optimized independently and facilitates the trip-free function where the release mechanism can actuate the switch-off without handle involvement, resolving the reliability issue when contacts age
Solution Approach 2:
The connecting rod assembly acts as an intermediary mechanism between the input shaft and output shaft. It includes a release mechanism that can directly actuate the output shaft to separate the contacts, bypassing the need for handle operation. This intermediary structure ensures reliable switch-off even when the handle or contact surfaces are degraded by aging and harsh environmental conditions
2Reliability
If friction between movable contact and stationary contact increases due to aging and rust, then the contact surfaces become difficult to separate, but the conventional switch mechanism cannot provide sufficient driving force
Solution Approach 1:
The patent employs a dynamic release mechanism where the connecting rod assembly can directly actuate the output shaft to rapidly separate the contacts. This dynamic action provides sufficient driving force to overcome increased friction and adhesion forces caused by aging and rust, ensuring reliable switch-off without requiring excessive manual force on the handle
Solution Approach 2:
The release mechanism is pre-configured to directly actuate the output shaft when needed. This preliminary preparation of the actuation path allows the system to quickly generate sufficient separating force between contacts when switch-off is required, overcoming rust and adhesion without relying on gradual handle rotation against high friction
3Ease of operation
If the handle is used to drive the input shaft to rotate for switch-off, then the operation is simple, but the handle may get stuck and prevent reliable switch-off
Solution Approach 1:
The patent separates the handle operation from the actual contact separation function. The handle drives the input shaft, but the connecting rod assembly includes a release mechanism that can independently actuate the output shaft. This segmentation ensures that even if the handle gets stuck, the release mechanism can still perform the switch-off function, providing trip-free capability while maintaining ease of normal operation
Solution Approach 2:
The connecting rod assembly serves as an intermediary that decouples the handle operation from contact separation. The release mechanism within the connecting rod assembly can directly actuate the output shaft to separate contacts without requiring handle rotation. This intermediary structure eliminates the reliability issue of stuck handles while preserving simple manual operation for normal switching
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 solution ensures reliable separation of movable and stationary contacts, prolongs the service life of the switch, and reduces maintenance costs by providing a larger driving force and trip-free functionality, enhancing safety and reliability.
Implementation Method 1
the input shaft is configured to drive the input connecting rod to rotate, so that the input connecting rod collides with the output connecting rod, and the output connecting rod drives the output shaft to rotate
Data Source
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AI summary
This application provides a direct current switch and a power converter including the direct current switch. The direct current switch includes an operating mechanism, a handle, and a disconnector. The operating mechanism includes an input shaft, an output shaft, and a connecting rod assembly, and the connecting rod assembly includes an input connecting rod and an output connecting rod. The disconnector includes a plurality of stacked sub-switches, and each sub-switch includes a movable contact and a stationary contact. The input shaft is fastened to the handle, the connecting rod assembly is configured to be in transmission connection to the input shaft and the output shaft, and the output shaft is configured to drive the movable contact to rotate. The handle is configured to drive the input shaft to rotate, and the input shaft is configured to drive the input connecting rod to rotate, so that the input connecting rod collides with the output connecting rod, and the output connecting rod drives the output shaft to rotate, to separate the movable contact from the stationary contact. In this way, when friction between the movable contact and the stationary contact increases, or when rust or adhesion occurs between the movable contact and the stationary contact, larger driving force can be provided for the movable contact, to reliably separate the movable contact from the stationary contact.