Battery Pack Switch Retention Circuit for Fault-State Hold
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Solution Overview
Problem
Existing battery packs may unintentionally disconnect from the vehicle body due to control device faults, posing safety risks, especially during high-speed operation.
Innovation Solution
A switch control device with a retention circuit that maintains the switch state for a predetermined time upon detecting a fault, using a trigger signal, reset signal, and retention signal to generate a switch control signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a control device controls a switch connecting a battery pack to a vehicle body, then the switch can be controlled to connect or disconnect the battery pack, but if a fault occurs in the control device, the control signal may not be maintained and the switch state may change unintentionally causing safety risks
Solution Approach 1:
The retention circuit is configured to detect faults in the control device and maintain the switch state in its previous operating state for a predetermined time period before allowing any state change. This preliminary action of detecting faults and retaining the state prevents unintentional disconnections that could cause safety risks during high-speed operation or critical moments.
2Reliability
If a retention circuit is added to maintain switch state during faults, then safety is improved by preventing unintentional disconnection, but the device complexity increases
Solution Approach 1:
A retention circuit is introduced as an intermediary component between the control device and the switch. This retention circuit includes a trigger signal generator, reset signal generator, and retention signal generator that work together to detect faults and maintain the switch state. The intermediary retention circuit adds complexity but provides the necessary fault protection functionality.
3Object-affected harmful factors
If the switch state is maintained for a predetermined time upon fault detection, then safety is improved by preventing sudden disconnection, but the response time to actual faults is delayed
Solution Approach 1:
The retention circuit operates with periodic characteristics by maintaining the switch state for a predetermined time period after fault detection. The trigger signal generator detects faults and generates trigger signals, the reset signal generator creates reset signals with specific pulse widths, and the retention signal generator outputs retention signals for controlled durations. This periodic retention approach balances safety by preventing immediate disconnection while eventually responding to faults.
Data Source
AI summary
A switch control device includes a retention circuit configured to generate a trigger signal based on a fault signal indicating whether a fault indicated by a power signal occurred, generate a reset signal based on the trigger signal, store a present value of a driving signal at a time during a duration of an active edge of the trigger signal, and output the stored driving signal as a retention signal during a time duration of the reset signal; and a driving circuit configured to generate a switch control signal based on the retention signal and the driving signal, and output the switch control signal to a switch.