High Voltage Interlock Device with Dual-Path Failure Diagnosis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional interlock devices for high voltage apparatuses, such as electric compressors, fail to accurately detect connector disconnection due to short-circuiting or device failure, leading to potential safety hazards.
Innovation Solution
An interlock device with a detecting signal output unit, first and second switching elements, and a failure diagnosis unit that diagnoses the state of the interlock loop by outputting L/H signals and inverting the ON/OFF state of the first switching element based on the controlling voltage switching circuit, allowing for accurate detection of connector connection or disconnection and interlock device failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional interlock loop is used to detect connector disconnection, then the device can detect connector connection status, but it cannot accurately detect disconnection when the interlock loop is short-circuited or when the device itself fails
Solution Approach 1:
The detection function is segmented into multiple independent pathways: a primary detection path using the interlock loop and a secondary self-diagnosis path using additional switching elements and detection circuits. This segmentation allows the system to detect both connector status and device integrity independently, resolving the contradiction between detection accuracy and reliability.
Solution Approach 2:
The invention implements feedback mechanisms where detection circuits continuously monitor the state of switching elements and interlock loop, and feed this information back to determine both connector connection status and device health. The dual-feedback paths enable accurate detection even when one path is compromised, addressing the reliability issue.
2Reliability
If additional detection circuits and switching elements are added to improve failure diagnosis capability, then the device can diagnose interlock loop failures, but the device complexity increases
Solution Approach 1:
The additional switching elements and detection circuits serve multiple functions: they act as self-diagnosis components for detecting interlock loop failures, while also participating in the primary connector status detection. This multi-functionality reduces the overall complexity increase by making components work for both diagnostic and operational purposes.
Solution Approach 2:
The interlock device performs self-diagnosis using its own internal switching elements and detection circuits, without requiring external diagnostic equipment or complex external monitoring systems. The device monitors its own health status through the self-service mechanism, achieving improved reliability with minimal added complexity.
Data Source
AI summary
Provided is an interlock device for a high voltage apparatus which enables not only the diagnosis of the connected or non-connected state of a connector during normal operation of the interlock device, but also the detection of a failure of the interlock device itself, including a failure of the interlock loop. The device includes an interlock loop 16 annexed to an HV connector 7 for connecting an electric compressor to an HV battery 8, a detecting signal output unit, a first switching element, a controlling voltage switching circuit operable, in a closed state of the interlock loop, to switch a voltage applied to a control electrode of the first switching element according to an output of the detecting signal output unit, a second switching element operable, in an open state of the interlock loop, to apply to the control electrode of the first switching element an output of the controlling voltage switching circuit so as to cause an ON/OFF state of the first switching element to be inverted from when the interlock loop is in the closed state, and a failure diagnosis unit.