High Voltage Interlock Circuit Using Serial Communications
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Solution Overview
Problem
Hybrid-electric and electric vehicles present high terminal-to-terminal voltage differentials in batteries and capacitors, posing a risk of exposure to high electrical voltages for personnel, as existing interlock circuits and connectors may not adequately isolate these voltages during connector opening.
Innovation Solution
A system utilizing a serial communication bus to control the connection of electrical power sources, incorporating a power cable interrupter and signal interpreter to isolate the electrical power source by monitoring bus traffic and impedance, allowing for safe disconnection and reconnection of high voltage connectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional dedicated interlock circuits are used in four or five wire connectors, then high voltage isolation is achieved, but device complexity and wiring requirements increase
Solution Approach 1:
The serial communication bus is designed to perform multiple functions: it carries both data communication traffic and interlock circuit functions. The same physical bus infrastructure is used for both purposes, eliminating the need for separate dedicated interlock wiring and reducing overall system complexity while maintaining high voltage isolation reliability
Solution Approach 2:
The patent combines the interlock circuit functionality with the existing serial communication bus infrastructure. By merging these two previously separate functions into a single communication channel, the system reduces wiring requirements and device complexity while achieving the same high voltage isolation protection
2Device complexity
If serial communication bus is used for interlock functions, then device complexity is reduced, but detection precision of connector status may worsen
Solution Approach 1:
The patent introduces an intermediary mechanism by monitoring bus traffic patterns and impedance characteristics as indirect indicators of connector status. The signal interpreter acts as an intermediary that translates communication bus parameters into reliable connector status detection, maintaining measurement precision while using the simpler serial communication infrastructure
Solution Approach 2:
The system continuously monitors serial communication bus traffic and impedance levels, providing feedback about connector connection status. This feedback mechanism enables the signal interpreter to detect connector opening/closing events accurately by analyzing changes in communication patterns, maintaining detection precision without requiring complex dedicated sensing circuits
3Object-affected harmful factors
If power cable interrupter is added to enable isolation, then safety against high voltage exposure is improved, but device complexity increases
Solution Approach 1:
The power cable interrupter is designed to open automatically in advance before personnel could be exposed to high voltage during connector separation. The system detects connector opening events through serial communication monitoring and triggers the interrupter to isolate the power source proactively, preventing harmful exposure before it can occur
Solution Approach 2:
The power cable interrupter operates autonomously based on signals from the serial communication bus monitoring system. When the signal interpreter detects connector status changes through bus traffic analysis, it automatically controls the interrupter without requiring additional complex control circuits or manual intervention, achieving safety through self-service operation
Data Source
AI summary
The system provides for controlling the connection of electrical power sources to electrical loads installed on a motor vehicle and limiting exposure of personnel to relatively high electrical voltages from the electrical power sources. The system includes a serial communication bus and power cables routed through the motor vehicle. At least a first connector is provided through which the serial communication bus and a power cable are routed allowing temporary severing of the serial communication bus and the power cable. The power cable includes a circuit interrupter which isolates the connector from the electrical power source in response to certain conditions on the serial communication bus, including, but not limited to, the cessation of data traffic on the serial communication bus.