DC-DC Converter Disabling via Voltage Comparison
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Solution Overview
Problem
In voltage supply systems with DC-DC converters, a contactor fault can lead to continuous discharge of the battery with higher operation voltage, potentially causing complete discharge, as existing systems lack effective mechanisms to prevent this.
Innovation Solution
A voltage supply system that includes a microprocessor, voltage sensors, and a DC-DC voltage converter, where the microprocessor disables the DC-DC converter's operation if the contactor is stuck in a closed position, preventing further discharge by stopping the output voltage application to the second battery when the first battery's voltage level falls below a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the contactor is used to switch between batteries for extended periods, then the system can maintain operational flexibility, but the contactor deteriorates and may become stuck in a closed position causing continuous discharge
Solution Approach 1:
The microprocessor performs preliminary detection by comparing voltage levels between the first battery and the electrical node before allowing DC-DC converter operation. This preliminary check prevents the converter from operating when the contactor is stuck closed, thereby preventing continuous discharge and addressing the reliability issue before it manifests as a complete battery discharge
Solution Approach 2:
The system continuously monitors voltage levels through voltage sensors and provides feedback to the microprocessor. The microprocessor compares the first voltage level (across the first battery) with the second voltage level (across the electrical node) and uses this feedback to determine whether the contactor is properly open or closed, enabling real-time detection of stuck contactor conditions
2Productivity
If the DC-DC voltage converter operates continuously to charge the second battery, then energy transfer efficiency is improved, but the first battery may be completely discharged if the contactor fails
Solution Approach 1:
The microprocessor performs a preliminary voltage comparison check before enabling DC-DC converter operation. By verifying that the contactor is properly open (indicated by appropriate voltage differences), the system prevents the converter from operating in a fault condition, thereby eliminating the risk of complete battery discharge while allowing continuous operation under normal conditions
Solution Approach 2:
The voltage sensors and microprocessor comparison logic serve as intermediaries between the contactor state and the DC-DC converter operation. This intermediary detection mechanism translates the physical contactor position into an electrical signal that controls converter enablement, preventing harmful operation without requiring direct mechanical intervention
Data Source
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AI summary
A voltage supply system having a first battery with a first positive electrode and a first negative electrode, and a contactor coupled in series between the first positive electrode and an electrical node is provided. The system includes a first voltage sensor generating a signal indicative of a first voltage level of the first battery, and a second voltage sensor generating a signal indicative of a second voltage level between the electrical node and the first negative electrode. The system includes a DC-DC voltage converter coupled between the electrical node and the first negative electrode; and a second battery, and a microprocessor. The microprocessor disables operation of the DC-DC voltage converter such that the converter does not apply a voltage to the second battery, if both the first voltage level is substantially equal to the second voltage level, and the first voltage level is less than a first threshold voltage level.