Non-Contact Switch Status Detector for Electric Vehicles
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Solution Overview
Problem
Conventional methods for detecting the insulation status of high-voltage and high-current switching assemblies in electric vehicles are complex and unreliable, often involving direct circuit measurements or micro-switches that can be affected by high voltages and prone to breakdown.
Innovation Solution
A contact-free switch status detector using an electronic oscillator coupled with a coil wrapped around a core, which outputs an oscillating voltage varying with the switch position, allowing remote and electrical isolation from the switch, enabling detection of the switch's open or closed position without exposing the detector to high voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a micro-switch is used to detect the position of the switching assembly, then the position can be detected, but the reliability deteriorates because parts of the micro-switch can break down and high voltage can be present at the micro-switch
Solution Approach 1:
A non-contact sensor (optical, magnetic, or capacitive) is introduced as an intermediary to detect the position of the contact bridge without direct electrical connection. This mediator allows position detection while maintaining electrical isolation, preventing high voltage from reaching the sensor and eliminating mechanical wear that causes micro-switch failures.
Solution Approach 2:
The mechanical micro-switch system is replaced with a non-contact sensing system (optical, magnetic, or capacitive fields). This substitution eliminates mechanical contact and wear, providing reliable position detection without exposure to high voltage or mechanical breakdown risks.
2Measurement precision
If direct circuit measurement is used to detect insulation status, then the insulation status can be detected, but the device complexity increases due to auxiliary relays and complex measurement circuits
Solution Approach 1:
The measurement function is extracted from the high-voltage circuit domain and placed in a separate, isolated sensing domain. The non-contact sensor detects position information without requiring auxiliary relays or complex high-voltage measurement circuits, simplifying the overall system architecture.
Solution Approach 2:
A non-contact sensor serves as an intermediary that detects contact bridge position without direct electrical connection to the high-voltage circuit. This eliminates the need for auxiliary relays and complex measurement circuits, providing simple insulation status detection through position monitoring.
3Reliability
If the switch status detector is positioned remotely and electrically isolated from the switch, then safety is improved by preventing high voltage exposure, but the detection capability must be maintained through non-contact sensing
Solution Approach 1:
Direct mechanical or electrical contact-based detection is replaced with non-contact sensing (optical, magnetic, or capacitive fields). This allows the detector to be positioned remotely and electrically isolated while maintaining full detection capability through field-based sensing of the contact bridge position.
Solution Approach 2:
A non-contact sensor acts as an intermediary that bridges the gap between the high-voltage switch and the isolated detector. Through optical, magnetic, or capacitive coupling, it transmits position information across the electrical isolation boundary, enabling safe remote detection without compromising detection accuracy.
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 solution simplifies the detection process, enhances reliability by preventing high voltage exposure, and allows for the identification of wear and tear on the switching device, providing continuous position detection and improved safety during maintenance.
Implementation Method 1
an electronic oscillator coupled with a coil wrapped around a core
Implementation Method 2
The armature 6 is positioned in a coil 7
Data Source
AI summary
A switch assembly comprises a plurality of contacts, a switch including a contact bridge and an armature connected to the contact bridge, and a switch status detector positioned remotely and electrically isolated from the switch. The switch has an open position in which the contacts are electrically separated from one another and a closed position in which the contacts are in electrical contact with each other through the contact bridge. The switch status detector includes an electronic oscillator coupled with a coil wrapped around a core. The switch status detector outputs an oscillating voltage that varies depending upon a position of the switch between the open position and the closed position.