UPS Battery Management Circuit for Discharge Current Monitoring
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Solution Overview
Problem
In uninterruptible power supplies (UPS) with multiple battery strings, process variations lead to inconsistent battery characteristics, causing some batteries to discharge below permissible levels, resulting in premature damage and reduced lifespan.
Innovation Solution
A battery management system comprising a battery management circuit and control circuit that measures voltage across each battery, calculates discharge current, and determines if it has dropped to an end-of-discharge voltage, triggering a control signal to stop discharging of affected battery strings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If multiple battery strings are used in parallel to increase discharge time, then the discharge time of UPS is extended, but process variations cause some batteries to discharge below permissible levels resulting in early damage
Solution Approach 1:
The control circuit continuously monitors the voltage of each battery through the battery management circuit and uses this feedback information to calculate discharge currents and determine when batteries reach their end-of-discharge voltage thresholds, enabling real-time adjustment of discharge control
Solution Approach 2:
The system divides the battery management into individual battery-level control, where each battery's voltage and discharge current are monitored and controlled independently through separate control signals applied to switching elements in each battery string, allowing differential discharge management
2Adaptability or versatility
If batteries with different characteristics are discharged in parallel, then the system can operate with varied battery specifications, but the worst-characterized batteries discharge below EOD voltage causing early damage and affecting other battery strings
Solution Approach 1:
The system applies different discharge control strategies to different battery strings based on their individual characteristics. Each battery string receives customized control signals tailored to its specific end-of-discharge voltage threshold and discharge rate, allowing batteries with different specifications to operate together without harming the most vulnerable ones
Solution Approach 2:
The control circuit pre-establishes end-of-discharge voltage thresholds for each battery based on their characteristics before discharge begins. During discharge, the system proactively monitors and stops discharge before any battery can reach damaging low-voltage levels, preventing over-discharge damage before it occurs
Data Source
AI summary
The invention provides an uninterruptible power supply, which comprises a battery management circuit and a control circuit. The battery management circuit is electrically coupled to each battery of at least one battery string for measuring the voltage of each battery. When the battery strings discharge, the control circuit obtains the voltage of each battery through the battery management circuit to calculate the discharge current of each battery, and determines whether there is any measured voltage having dropped to an EOD voltage corresponding to a discharge current of a corresponding battery. When the determination result is positive, the control circuit controls the uninterruptible power system to stop the discharging of at least one battery string in which there is at least one measured voltage having dropped to an EOD voltage corresponding to a discharge current of a corresponding battery. Furthermore, a corresponding battery management apparatus is also provided.