Backup Power Charging Sequence to Prevent False Outage Detection
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Solution Overview
Problem
Backup power supply devices experience false detection of power failure during charging due to instantaneous voltage drops caused by inrush currents, leading to unnecessary discharge of secondary batteries.
Innovation Solution
A backup power supply device with parallel-connected secondary batteries, individual charging switches, and a control device that manages charging with a time difference between battery start timings to disperse inrush currents, preventing voltage drops below the power failure detection threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple secondary batteries are charged in parallel simultaneously, then charging efficiency is improved, but instantaneous voltage drop occurs due to inrush current causing false power failure detection
Solution Approach 1:
The charging operation is segmented into sequential phases rather than simultaneous charging. The control device charges batteries one by one in a predetermined sequence, dividing the simultaneous charging process into multiple time-separated charging stages. This segmentation reduces the total inrush current at any given moment, preventing voltage drops that would trigger false power failure detection while maintaining overall charging efficiency.
2Loss of time
If charging voltage is increased to charge batteries faster, then charging time is reduced, but inrush current increases causing voltage drop below detection threshold
Solution Approach 1:
Before initiating charging of each battery, the control device performs preliminary actions by sequentially enabling charging switches in a predetermined order. This preliminary sequencing ensures that not all batteries draw maximum current simultaneously, pre-preventing the voltage drop condition before it can occur. The controlled sequential activation maintains faster overall charging while avoiding the harmful voltage threshold drop.
3Device complexity
If all charging switches are activated at once, then charging process is simplified, but false discharging control is triggered due to voltage drop
Solution Approach 1:
The charging control system dynamically adjusts the activation timing of charging switches based on predetermined sequences rather than static simultaneous activation. The control device monitors and controls each charging switch's activation timing dynamically, enabling batteries to charge in a coordinated sequence. This dynamic control prevents false power failure detection while maintaining manageable system complexity through automated sequence management.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Suppresses false power failure detection during charging, allowing for reliable operation by maintaining the power supply voltage above the detection threshold and ensuring timely charging of batteries.
Implementation Method 1
an instantaneous voltage drop of the power supply voltage may occur due to an inrush current flowing in from the external power supply into each secondary battery
Data Source
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AI summary
A backup power supply device (1) to be connected to a conduction path (P) from an external power supply (3) to an external load (4) including a plurality of secondary batteries (B1-B7) connected in parallel, a plurality of charging switches (SW1-SW7) that can individually pass and cut off charging power from the conduction path (P) to the plurality of secondary batteries (B1-B7), and a control device (10) for performing discharging control on the plurality of secondary batteries (B1-B7) when the power supply voltage of the conduction path (P) drops below a predetermined power failure detection threshold value, when battery voltages of the plurality of secondary batteries (B1-B7) drop below a predetermined charging start threshold value, the control device (10) performing charging control with a time difference (TD) set between charging start timings of the secondary batteries (B1-B7).