Dual Power Supply Switch Control for Noise-Robust Fault Isolation
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Solution Overview
Problem
Existing power supply devices experience repeated conduction and disconnection of the inter-system switch due to voltage fluctuations caused by noise, leading to a loss of electric power during fail-safe control when a ground fault occurs.
Innovation Solution
A power supply control device with a controller that includes a comparison circuit, pulse generator, latch circuit, and microcomputer to detect power supply failures, output a pulse signal to disconnect the connection device, and periodically confirm the occurrence of failures, preventing repeated disconnection and maintaining stored electric power for fail-safe control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the inter-system switch is immediately disconnected upon detecting voltage fluctuation, then the response speed to ground fault is improved, but the switch may repeatedly conduct and disconnect due to noise-induced voltage vibrations
Solution Approach 1:
The control unit performs preliminary inspection of both power supply systems before disconnecting the inter-system switch. When voltage fluctuation is detected, the control unit first inspects the first power supply system and second power supply system to confirm a ground fault before executing disconnection, thereby avoiding premature action due to noise while maintaining rapid response capability.
Solution Approach 2:
The control unit continuously monitors voltage levels and switch states, using feedback from voltage detection circuits to dynamically adjust control decisions. The inspection results from both power supply systems are fed back to determine whether disconnection is necessary, creating a closed-loop control system that distinguishes between noise and actual ground faults.
2Measurement precision
If the inter-system switch is repeatedly disconnected during inspection period, then the detection of power supply failure is improved, but the stored electric power for fail-safe control decreases
Solution Approach 1:
The control unit performs preliminary inspection of both power supply systems before disconnecting the inter-system switch. When voltage fluctuation is detected, the control unit first inspects the first power supply system and second power supply system to confirm a ground fault before executing disconnection, thereby avoiding premature action due to noise while maintaining rapid response capability.
Solution Approach 2:
The control unit continuously monitors voltage levels and switch states, using feedback from voltage detection circuits to dynamically adjust control decisions. The inspection results from both power supply systems are fed back to determine whether disconnection is necessary, creating a closed-loop control system that distinguishes between noise and actual ground faults.
Data Source
AI summary
A controller of a power supply control device includes: a comparison circuit configured to compare a parameter related to a power supply failure of a first system or of a second system with a threshold and to output a detection signal indicating an occurrence of the power supply failure; a pulse generator configured to output a pulse signal having a predetermined pulse width in response to receiving the detection signal and to disconnect the connection device to disconnect connection between the first system and the second system during a period in which the pulse signal is output; a latch circuit configured to latch the pulse signal; and a microcomputer configured to periodically acquire a latch state of the latch circuit and to determine, in response to detecting that the pulse signal is latched, in which of the first system and the second system the power supply failure occurs.