EV On-Board Power Switch Latch for Voltage Fault Isolation
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Solution Overview
Problem
Existing on board power supply apparatuses for electric vehicles suffer from repeated turn-on and turn-off of the switch circuit, leading to damage and energy wastage due to undervoltage and overvoltage conditions, compromising security and reliability.
Innovation Solution
Incorporating a latch circuit within the switch module that controls the connection between the low-voltage power supply and load, breaking the connection upon undervoltage or overvoltage and maintaining it latched until the voltage returns to a normal range, preventing reconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the switch circuit is used to connect and disconnect the low-voltage power supply from the low-voltage load based on voltage thresholds, then undervoltage and overvoltage protection is achieved, but the switch circuit repeatedly turns on and off causing damage and energy wastage
Solution Approach 1:
The latch circuit is activated in advance when the voltage abnormality occurs, and remains latched thereafter. This preliminary action prevents the switch circuit from repeatedly operating, thereby avoiding energy wastage while maintaining the protection function.
Solution Approach 2:
The latch circuit acts as an intermediary between the voltage detection mechanism and the switch circuit. It translates the voltage threshold detection into a latched state that controls the switch circuit, preventing repeated switching while maintaining protection.
2Reliability
If the switch circuit is repeatedly turned on and off to maintain voltage protection, then the protection function is maintained, but the switch circuit suffers damage reducing its reliability
Solution Approach 1:
The latch circuit is activated in advance when the voltage abnormality occurs, and remains latched thereafter. This preliminary action prevents the switch circuit from repeatedly operating, thereby avoiding damage and improving switch circuit durability while maintaining the protection function.
Solution Approach 2:
The latch circuit acts as an intermediary between the voltage detection mechanism and the switch circuit. It translates the voltage threshold detection into a latched state that controls the switch circuit, preventing repeated switching and reducing mechanical stress on the switch components.
3Duration of action of stationary object
If the switch circuit automatically reconnects when voltage returns to normal, then continuous power supply is maintained, but repeated switching causes damage and energy wastage
Solution Approach 1:
The latch circuit is activated in advance when the voltage abnormality occurs, and remains latched even after voltage returns to normal. This preliminary action prevents the switch circuit from repeatedly operating during voltage recovery, thereby avoiding energy wastage while the system can be manually or automatically reset when appropriate.
Solution Approach 2:
The latch circuit acts as an intermediary that decouples the automatic reconnection behavior from the voltage recovery. It maintains the latched state during voltage recovery, preventing automatic repeated switching, and allows controlled reconnection only when a reset signal is received.
Data Source
AI summary
This application provides an on board power supply apparatus and an electric vehicle, which effectively resolves problems of easy damage to a switch circuit and a waste of electrical energy due to repeated turn-on of the switch circuit. The on board power supply apparatus includes a first power conversion circuit and a switch module. The switch module includes a driver, a switch assembly, and a latch circuit. A low-voltage load is configured to receive the low-voltage direct current or receive an output voltage of a low-voltage power supply through the switch assembly. When the low-voltage power supply supplies power to the low-voltage load through the switch assembly, in response to a turn-off signal output by the latch circuit, the driver controls the switch assembly to break a connection between the low-voltage power supply and the low-voltage load until the latch circuit stops outputting the turn-off signal.