High-Voltage Circuit Control for Vehicle Torque Recovery
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Solution Overview
Problem
High voltage circuits in vehicles, such as hybrid electric vehicles, are often shut down in response to faults to prevent electric shock, but this renders the vehicle inoperable, especially when moving, as the HV circuit is necessary for continued use and propulsion.
Innovation Solution
A method and system that allows the high-voltage circuit to be increased in voltage upon detecting a torque request, even in the presence of a fault, to enable vehicle movement while ensuring safety by reducing voltage to a safety level when stationary or not in use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the high-voltage circuit is shut down in response to a fault to prevent electric shock, then safety is improved, but the vehicle becomes inoperable and cannot respond to torque requests
Solution Approach 1:
The patent applies dynamics by making the voltage control state changeable based on real-time conditions. The controller dynamically adjusts the high-voltage circuit state between shutdown and operational modes depending on whether torque requests are received, vehicle speed conditions are met, and fault types are identified. This allows the system to transition from a static safe-but-inoperable state to a dynamic state that can provide both safety and operability when conditions permit.
Solution Approach 2:
The patent changes the voltage parameter of the high-voltage circuit based on operational conditions. When a torque request is received and vehicle speed exceeds the threshold, the controller increases the voltage from a safe shutdown level to an operational level, enabling the electric machine to provide propulsion while maintaining safety through conditional parameter adjustment.
2Object-affected harmful factors
If the high-voltage circuit remains shut down after fault detection, then safety is maintained, but the vehicle cannot move or respond to driver input
Solution Approach 1:
The system dynamically transitions from a static shutdown state to an operational state when specific conditions are met (torque request received and vehicle speed above threshold). This dynamic behavior allows the vehicle to recover mobility while maintaining safety through conditional activation rather than permanent shutdown.
Solution Approach 2:
The patent converts the harmful fault condition into a beneficial outcome by using the fault detection system to trigger a conditional recovery process. When the vehicle is already moving (speed above threshold), the system can safely reactivate the high-voltage circuit in response to torque requests, turning a potentially stranding situation into a controlled operational recovery.
3Reliability
If the high-voltage circuit is immediately shut down upon fault detection, then safety response time is reduced, but the vehicle may be stranded even when capable of safe operation
Solution Approach 1:
The controller implements dynamic conditional control rather than immediate permanent shutdown. It continuously monitors vehicle speed and torque requests, allowing the high-voltage circuit to be reactivated when safe operating conditions are detected (vehicle speed above threshold), thereby reducing unnecessary downtime while maintaining rapid safety response capability.
Solution Approach 2:
The system performs preliminary fault assessment and maintains the capability for rapid shutdown if new faults occur, while simultaneously preparing for safe recovery by monitoring vehicle speed and torque requests. This preliminary preparation allows for quick safety responses when needed while enabling timely recovery when conditions permit.
Data Source
AI summary
Embodiments of the present invention provide a method of controlling a high-voltage circuit (15) of a vehicle, comprising detecting (310) a fault associated with the high-voltage circuit, reducing (320) a voltage of the high-voltage circuit (15) in dependence on detecting the fault, receiving (330) a torque request and, in dependence thereon, increasing (340) the voltage of the high-voltage circuit (15).