Electric Vehicle Discharger Power Path Segmentation
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Solution Overview
Problem
In electric vehicles, the power supply harness can experience ground faults or overcurrents during collisions, leading to disconnection and potential failure of the discharger system, which is critical for safely discharging capacitors and maintaining system stability.
Innovation Solution
The electric vehicle incorporates an interrupter to isolate the step-down converter from the power supply harness when abnormalities are detected, allowing the discharger to receive power through an alternative path, ensuring continuous operation and stable voltage supply to the discharger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply harness is isolated from the power system when a specific abnormality is detected, then safety is improved, but the discharger cannot receive electric power and cannot discharge the capacitor
Solution Approach 1:
The power supply path is divided into two separate paths: a first power supply path that connects the step-down converter output to the discharger upstream of the interrupter, and a second power supply path that connects through the power supply harness downstream of the interrupter. This segmentation allows the discharger to receive power from the first path when the interrupter isolates the second path, resolving the contradiction between safety isolation and discharger operation.
2Reliability
If the power supply harness contacts a metal portion causing a ground fault, then overcurrent flows and the overcurrent protection circuit activates, but the discharger loses power supply
Solution Approach 1:
The first power supply path acts as an intermediary route that bypasses the vulnerable power supply harness. When the harness experiences a ground fault and the interrupter activates, the discharger can still receive power through the first path from the step-down converter output, maintaining discharger operation while the overcurrent protection remains active through the second path isolation.
3Reliability
If the interrupter isolates the step-down converter from the power supply harness, then the step-down converter is protected from ground faults, but the discharger cannot operate through the power supply harness
Solution Approach 1:
The power supply system is segmented into two independent paths: the first path provides power to the discharger upstream of the interrupter, and the second path provides power through the power supply harness downstream of the interrupter. When the interrupter isolates the second path to protect the step-down converter, the discharger continues to operate through the first path, resolving the contradiction between converter protection and discharger operation.
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
This configuration ensures reliable operation of the discharger even during ground faults or overcurrents, maintaining system stability and preventing damage by providing a secondary power path to the discharger, thus enhancing safety and functionality post-collision.
Implementation Method 1
converts electric power stored in the capacitor to thermal energy to consume the electric power by, for example, connecting the capacitor to a discharge resistor having a large heat generation amount through energization
Data Source
AI summary
An electric vehicle includes: a main battery; an electric power converter configured to convert power to driving power of a drive motor; an auxiliary battery configured to supply power to auxiliaries; a power supply harness connecting the auxiliary battery to the auxiliaries; a step-down converter having an output end connected to the power supply harness, the step-down converter being configured to step down an output voltage of the main battery to the driving voltage of the auxiliaries; an interrupter configured to isolate the step-down converter from the power supply harness at the time when a predetermined specific abnormality has been detected; and a discharger configured to discharge a capacitor incorporated in the electric power converter, the discharger being configured to operate by receiving electric power supplied from a first power supply path which connects the output end of the step-down converter to the interrupter.