High-Voltage Load Switch with Arc-Free Contact Disconnection
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Solution Overview
Problem
High-voltage electrical load circuit switches in electric vehicles experience premature wear due to arcing and contact erosion, especially during extreme conditions like driving through potholes, leading to frequent replacements.
Innovation Solution
A device with a contact stud connected to a linear drive, featuring a stepper motor and solenoid for precise control, and a gas generator for rapid disconnection, preventing unintentional opening and ensuring reliable switching with a third contact ring for grounding in emergencies, thus preventing arcing and extending service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contactor is used to switch the load circuit, then the switching function is achieved, but the contacts open unintentionally under extreme driving conditions leading to arcing and contact erosion
Solution Approach 1:
The load circuit is switched off before the switching device is actuated. The control unit receives a switching-off signal from the control device, which switches off the load circuit prior to the contactor being actuated by the linear drive. This preliminary switching-off prevents arcing and contact erosion during the switching process, thereby extending contact service life while maintaining switching reliability
Solution Approach 2:
A control unit acts as an intermediary between the control device and the contactor. The control unit receives signals from the control device, switches off the load circuit in advance, and only then allows the linear drive to actuate the contactor. This intermediary control logic prevents unintentional contact opening and arcing while ensuring reliable switching operation
2Ease of operation
If the contactor is actuated by magnetic force, then the switching operation is simple, but the contacts are vulnerable to opening under strong acceleration forces
Solution Approach 1:
The traditional magnetic force-based contactor actuation is replaced with a linear drive mechanism. The linear drive uses a rack and pinion gear system with a locking lever that mechanically locks the contactor in its actuated position. This mechanical substitution eliminates vulnerability to magnetic force failures and provides reliable contact stability even under strong acceleration forces, while the switching operation remains simple through automated control
Solution Approach 2:
The locking lever and rack-pinion gear system provide beforehand cushioning against unintended contactor opening. The locking lever engages with the rack to prevent backward movement, and the entire mechanical system is designed to withstand strong acceleration forces. This preemptive mechanical locking ensures contact stability before extreme conditions occur, preventing unintentional opening while maintaining simple automated operation
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 enables reliable and safe switching of high-voltage load circuits, preventing arcing and extending the service life by ensuring precise control and rapid disconnection, even under extreme conditions, and ensuring safe discharge in accidents.
Implementation Method 1
a linear drive (2) is provided, which has an operating position in which the contact stud (6) closes a circuit between the voltage source (7) and the load circuit (8) and a switching position in which the contact stud (6) opens the circuit between the voltage source (7) and the load circuit (8)
Implementation Method 2
A device with a contact stud connected to a linear drive, featuring a stepper motor and solenoid for precise control
Data Source
AI summary
Apparatus for switching an electrical load circuit operated at high voltage are disclosed. The embodiments described herein include a device for controlling the switching of a high voltage circuit such that both the connection and disconnection can be carried out in a simple and reliable manner. Embodiments described herein can also prevent the unintentional opening of the switching device which can greatly extend the service life of the switching circuitry. Moreover, the apparatus disclosed herein reliably prevent the formation of an arc during switching by enabling the switching operation to take place without a load.