Electric Vehicle Control Apparatus for DC/DC Converter Overcurrent Protection
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Solution Overview
Problem
In electric vehicle power supply systems, overcurrents from a traction inverter can flow to a DC/DC converter during self-protection, potentially damaging it when the inverter's switching operation is stopped.
Innovation Solution
An electric vehicle control apparatus with a self-protection circuit for the traction inverter and a current cut-off section that synchronizes with the self-protection circuit to prevent overcurrents from reaching the DC/DC converter, either by cutting off power from the first direct current power supply or stopping the DC/DC converter's switching operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the self-protection circuit stops the switching operation of the traction inverter to protect it from overcurrent, then the traction inverter is protected from damage, but overcurrent flows to the DC/DC converter causing potential damage
Solution Approach 1:
The control section detects overcurrent conditions and preemptively stops the DC/DC converter switching operation before overcurrent can reach the converter. This preliminary protective action prevents the harmful effect from occurring in the first place, rather than reacting after damage has begun.
Solution Approach 2:
The control section acts as an intermediary between the traction inverter's self-protection circuit and the DC/DC converter. When overcurrent is detected, the control section mediates by stopping the DC/DC converter switching, thereby protecting the converter from the harmful overcurrent while maintaining system coordination.
2Reliability
If the DC/DC converter switching operation is stopped to prevent overcurrent damage, then the converter is protected, but power supply to the vehicle is interrupted
Solution Approach 1:
The control section implements periodic monitoring of current conditions and uses periodic switching control of the DC/DC converter. When overcurrent is detected, switching is temporarily stopped; when normal conditions return, switching resumes. This periodic on-off control protects the converter while allowing power supply to continue during normal operation.
Solution Approach 2:
The DC/DC converter switching operation is made dynamic rather than static. The control section continuously adjusts the switching state based on real-time current conditions - enabling switching during normal operation for power supply continuity, and disabling it only when overcurrent threatens the converter. This dynamic adaptation resolves the contradiction between protection and continuity.
Data Source
AI summary
Control apparatus of an electric vehicle controls a power supply system of the electric vehicle equipped with a first direct current power supply apparatus for supplying direct current power to a traction inverter, and a second direct current power supply apparatus connected in parallel with the first direct current power supply apparatus via a DC/DC converter. This control apparatus is also provided with a relay for cutting off supply of power from the first direct current power supply apparatus to the traction inverter in synchronization with the operation of the self-protection circuit in the event that the self-protection circuit of the traction inverter operates as a result of overcurrents supplied by the first direct current power supply apparatus.