Virtual High-Voltage Interlock Using DC-DC Bus Safety Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hardwire-based high voltage interlock systems add complexity and cost to electric vehicle design by requiring additional wires and circuitry to protect against high voltage exposure, and may not effectively detect open wires or connectors until after the DC bus is charged, potentially leading to high voltage exposure.
Innovation Solution
A software-based virtual high voltage interlock system that uses an electronic control unit to provide a safety voltage to the DC bus, compares measured voltage readings from high voltage components to determine if open wires or connectors are present, and activates the vehicle battery pack to provide an operating voltage only if the readings are acceptable, thereby preventing fault conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hardwire-based high voltage interlock system is implemented, then high voltage exposure is protected against, but design complexity increases due to additional wires and circuitry
Solution Approach 1:
The patent replaces the mechanical hardwire-based monitoring system with a software-based virtual interlock system. The electronic control unit uses software to monitor voltage signals from high voltage components and determine the presence of open wires or connectors, eliminating the need for separate hardwire monitoring circuits while maintaining safety functionality.
Solution Approach 2:
The electronic control unit performs multiple functions: it controls the DC-to-DC converter, monitors high voltage components through their reported voltage signals, and executes the virtual interlock logic. This consolidation of functions into a single control unit reduces the need for dedicated monitoring circuitry and simplifies the overall system architecture.
2Reliability
If a hardwire-based high voltage interlock is used, then safety monitoring is provided, but detection of open wires or connectors occurs after DC bus charging, leading to high voltage exposure
Solution Approach 1:
The system performs preliminary monitoring of high voltage components during the DC bus charging process itself. The electronic control unit continuously receives and evaluates voltage signals from high voltage components before the DC bus reaches full operating voltage, enabling detection of open wires or connectors before high voltage exposure can occur.
Solution Approach 2:
The system implements continuous feedback monitoring where high voltage components report their voltage signals to the electronic control unit in real-time. The control unit evaluates these signals and can immediately detect faults, providing continuous safety monitoring throughout the charging process rather than delayed detection after charging completes.
3Device complexity
If internal high voltage component voltage signals are used for monitoring, then separate monitoring circuitry is eliminated, but voltage signal interpretation complexity increases
Solution Approach 1:
High voltage components report their own voltage signals to the electronic control unit, enabling the components to self-monitor and self-report their status. This eliminates the need for separate external monitoring circuitry while distributing the monitoring function across the existing components themselves.
Solution Approach 2:
The system monitors changes in voltage parameters reported by high voltage components to detect faults. By evaluating voltage signal characteristics and changes rather than requiring complex dedicated monitoring circuits, the system achieves fault detection using the existing electrical parameters already present in the high voltage system.
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 virtual high voltage interlock system reduces design complexity and enhances safety by effectively detecting open wires or connectors before charging the DC bus to operating voltage, preventing high voltage exposure and ensuring reliable operation.
Implementation Method 1
a DC-to-DC converter converts the battery voltage to the safety voltage (e.g., any suitable voltage 60 V or less)
Data Source
AI summary
A virtual high voltage interlock is disclosed that utilizes a software-based function (e.g., an electronic control unit) to determine if there are any open wires or connectors, based on voltage signals reported by internal components, to prevent high voltage exposure. The electronic control unit instructs a power source to charge a DC bus to a safety voltage, receives measured voltage readings, via a control area network, from at least one high voltage component coupled to the DC bus, and provides an operating voltage to the DC bus in response to the measured voltage readings being acceptable.