High Voltage Interlock Circuit Isolated Switching Modules

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Solution Overview

Problem

Current high voltage interlock circuits for new energy vehicles face damage and accuracy issues due to direct detection of high voltage signals, which can lead to incorrect fault detection when large external voltages are present.

Innovation Solution

The implementation of a high voltage interlock circuit with isolated switching modules and a detection method that alternately closes switching modules to prevent direct voltage detection, using isolated driving units and switching units to isolate signal detection terminals from input and output terminals, thereby avoiding damage and improving fault detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If direct voltage detection is used at input and output terminals of high voltage interlock circuit, then detection simplicity is improved, but controller damage risk increases due to large external voltage

Engineering Contradiction:
Improvedetection simplicityVSAvoidcontroller damage risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces switching modules as intermediary components between the high voltage terminals and the controller. These switching modules are controlled to connect or disconnect from the terminals, acting as a mediator that allows safe isolation. When the switching modules are disconnected, the controller is protected from high voltage damage while still enabling detection functionality when connected under controlled conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If direct voltage comparison is used to detect high voltage component status, then detection process is simplified, but detection accuracy deteriorates under large external voltage conditions

Engineering Contradiction:
Improvedetection process complexityVSAvoidfault detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The detection process is segmented into multiple independent switching modules (first switching module, second switching module, third switching module) that can be controlled independently. Each module handles specific detection tasks by selectively connecting to different terminals. This segmentation allows the system to perform complex multi-step detection sequences that improve accuracy by isolating measurement points and avoiding interference from large external voltages.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3940408B1High voltage interlock circuit and detection method thereof
Publication Date: 2022.10.26 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD
  • EP3940408B1 patent drawingFigure 1
  • EP3940408B1 patent drawingFigure 2~4
  • EP3940408B1 patent drawingFigure 5~6

AI summary

The application discloses a high voltage interlock circuit and a detection method thereof. The circuit comprises: a first switching module, one terminal of the first switching module is connected to a first power supply, and the other terminal of the first switching module is connected to one terminal of a high voltage component module and a first power ground; a second switching module, comprising a first driving unit and a first switching unit arranged in isolation, the first switching unit is arranged between a second power supply and a second power ground; a third switching module, comprising a second driving unit and a second switching unit arranged in isolation, the first driving unit and the second driving unit are both arranged between the high voltage component module and the first power ground, and the second switching unit is arranged between the third power supply and the second power ground; a fourth switching module, arranged between the fourth power supply and the first power ground; a controller, for determining the fault of the high voltage component module by using the first detection result at one terminal of the first switching unit and the second detection result at one terminal of the second switching unit. The embodiments of the application improve the accuracy of fault detection.