Battery Precharge Control for Capacitor Charging and Voltage Equalization
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Solution Overview
Problem
Existing battery control systems for power supply systems with parallel-connected batteries face challenges in efficiently eliminating voltage inequalities, especially when a capacitor is connected in parallel with the load, and when there are long idle times, leading to voltage differences due to self-discharge differences among batteries.
Innovation Solution
A battery control apparatus that determines which batteries to initially supply power for charging a capacitor based on voltage acquisition results, performing voltage equalization before power is supplied to the load, using precharge resistors to manage inrush currents and equalize voltages among batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage equalization is performed after power source apparatus operation stops using precharge resistor, then voltage difference between batteries is reduced, but voltage inequality occurs again when power source apparatus is reactivated due to capacitor charging
Solution Approach 1:
The patent performs voltage equalization among batteries while the power source apparatus is operating, before the operation stops. This preliminary action ensures that when the apparatus is reactivated, the batteries are already at equal voltage levels, preventing the voltage inequality problem that occurs when equalization is delayed until after shutdown.
Solution Approach 2:
The patent maintains continuous voltage equalization action during operation by having the control unit monitor battery voltages and activate precharge resistors as needed. This continuous action ensures voltage equality is maintained throughout operation, eliminating the need to stop operation for equalization and preventing voltage inequality upon reactivation.
2Object-affected harmful factors
If precharge resistor is used to charge capacitor from one battery, then inrush current is suppressed, but voltage difference occurs between the battery supplying power and other batteries
Solution Approach 1:
The patent divides the battery group into multiple segments and assigns different precharge resistors to different batteries. When capacitor charging is needed, the control unit selectively activates precharge resistors for specific batteries, allowing inrush current suppression while maintaining voltage equality across all batteries through coordinated control.
Solution Approach 2:
The control unit continuously monitors the voltage levels of all batteries and uses this feedback information to determine when to activate precharge resistors. This feedback mechanism ensures that precharge resistors are activated only when needed to suppress inrush current, while maintaining voltage equality among all batteries by preventing excessive discharge from any single battery.
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
This approach efficiently eliminates voltage inequalities among batteries connected in parallel, even with a capacitor, and ensures reliable voltage equalization, especially during long idle times, by prioritizing charging based on battery voltages and using precharge resistors to manage voltage differences.
Implementation Method 1
the parallel connection between the batteries is established through a precharge resistor. By causing the current to flow through the precharge resistor from the battery with high voltage to the battery with low voltage
Data Source
AI summary
Before power is supplied to a load from a capacitor and a plurality of batteries, a battery for initially supplying power for charging to the capacitor is determined from among the plurality of batteries, based on a result of acquiring the voltage of each battery, and voltage equalization of the plurality of batteries is performed in response to power for charging being supplied to the capacitor from the determined battery.