Series Capacitor Charging Control for Voltage Balance
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Solution Overview
Problem
Conventional power storage devices face issues with unequal charging of capacitor elements due to varying internal resistances, leading to premature deterioration and increased size as more elements are connected in series to maintain voltage, necessitating excessive margins and larger device sizes.
Innovation Solution
A power storage system with a controller that adjusts charging by switching capacitor elements between connected and disconnected states based on voltage differences, using resistors and switch elements to manage charging currents, thereby maintaining appropriate voltages and reducing element deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If capacitor elements are connected in series to maintain voltage, then voltage output is improved, but device size increases due to needing more elements
Solution Approach 1:
The patent implements dynamic switching of capacitor elements during charging operations. The controller selectively connects or disconnects individual capacitor elements based on their voltage levels, transforming the static series connection into a dynamic configuration. This allows the system to maintain appropriate voltage output while using fewer capacitor elements, thereby reducing device size.
Solution Approach 2:
The patent changes the operational parameters of capacitor elements by applying different charging strategies. Instead of uniform charging, the controller adjusts charging voltage and current distribution based on individual element states. This parameter optimization allows fewer elements to achieve the required voltage output, reducing the overall device size.
2Reliability
If more capacitor elements are connected in series, then voltage margin is improved, but premature deterioration occurs due to unequal charging
Solution Approach 1:
The patent applies local quality control by treating each capacitor element individually rather than uniformly. The controller monitors and adjusts charging parameters for each element based on its specific voltage level and state. This localized approach prevents overcharging of individual elements, eliminating the premature deterioration caused by unequal charging while maintaining adequate voltage margins.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the voltage levels of individual capacitor elements and adjusting charging operations accordingly. The controller uses this feedback information to prevent any single element from being overcharged, thereby extending element lifespan while maintaining sufficient voltage margins for reliable operation.
3Ease of operation
If uniform charging is applied to all capacitor elements, then charging simplicity is maintained, but voltage imbalance occurs due to varying internal resistances
Solution Approach 1:
The patent transforms the static uniform charging approach into a dynamic charging strategy. The controller actively adjusts charging distribution based on real-time voltage measurements of individual capacitor elements. This dynamic approach maintains voltage balance across elements with varying internal resistances while preserving charging simplicity through automated control.
Solution Approach 2:
The patent employs feedback control to detect voltage imbalances caused by varying internal resistances and automatically adjusts charging parameters to correct these imbalances. This feedback mechanism maintains voltage stability across all capacitor elements while keeping the charging operation simple through automated adjustment, eliminating the need for complex manual balancing procedures.
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
The system effectively charges capacitor elements without excessive voltage, reducing the number of elements needed, thus minimizing device size while preventing premature deterioration.
Implementation Method 1
One of both ends of each capacitor element of the plural capacitor elements is connected to one end of a corresponding resistor of the plural resistors. Another of the both ends of the each capacitor element is connected to one end of a corresponding switch element of the plural switch elements.
Implementation Method 2
a charging circuit configured to supply a charging current to the storage unit
Implementation Method 3
when a difference between a storage voltage of the each capacitor element and a reference voltage is equal to or larger than a predetermined first voltage difference value
Data Source
AI summary
A power storage system includes a storage unit, a charging circuit configured to supply a charging current to the storage unit, and a controller connected to the storage unit. The storage unit includes plural capacitor elements connected in series to one another each having both ends, plural resistors connected to the capacitor elements, and plural switch elements connected to the capacitor elements and the resistors. One of both ends of each capacitor element of the plural capacitor elements is connected to one end of a corresponding resistor of the plural resistors. Another of the both ends of the each capacitor element is connected to one end of a corresponding switch element of the plural switch elements. Another end of the corresponding resistor is connected to another end of the corresponding switch element. The corresponding switch element is configured to selectively switch between a connected state in which the one end of the corresponding switch element is connected to the another end of the corresponding switch element and a disconnected state in which the one end of the corresponding switch element is disconnected from the another end of the corresponding switch element. While the charging circuit supplies the charging current to the storage unit, the controller is configure to perform the following operation. The controller causes the corresponding switch element to be in the disconnected state when a difference between the storage voltage of the each capacitor element and the reference voltage is equal to or larger than a predetermined first voltage difference value. The reference voltage increases as the each capacitor element is charged. The controller causes the corresponding switch element to be in the connected state when the difference between the storage voltage of the each capacitor element and the reference voltage is larger than the predetermined first voltage difference value, and then, switches the corresponding switch element from the connected state to the disconnected state when the difference between the storage voltage of the each capacitor element and the reference voltage becomes smaller than a predetermined second voltage difference value.