Energy Storage Bank Control for Current and Power Limit Compliance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing energy storage systems face issues with non-uniform current and power distribution among banks due to temperature differences and variations in deterioration, leading to potential exceedance of current and power limits, even when aggregate control is maintained within target values.
Innovation Solution
An energy storage unit with a bank management device that calculates current or power limit values based on target and measurement values, adjusting these limits to prevent excess current or power, using arithmetic computations to ensure safe operation regardless of temperature variations and conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aggregate current control is maintained within target values, then system-level current control is achieved, but individual bank currents may exceed their current target values due to temperature differences and deterioration variations
Solution Approach 1:
The control system is segmented into bank-level control (individual current target values for each bank) and system-level control (aggregate current control). Each bank has its own current target value calculated based on its specific conditions (temperature, deterioration state), while the system overall maintains aggregate current within target values. This segmentation allows simultaneous achievement of both individual bank current accuracy and system-level current control.
Solution Approach 2:
The patent applies local quality by setting different current target values for different banks based on their individual characteristics. Banks with higher temperature or greater deterioration are assigned lower current target values, while banks in better condition receive higher current target values. This localized adjustment ensures each bank operates within safe current limits while maintaining overall system efficiency.
2Reliability
If current target values are set based on temperature and deterioration variations, then individual bank current limits are respected, but system-level current control becomes more complex
Solution Approach 1:
The system performs preliminary action by calculating and setting individual current target values for each bank before operation based on their temperature and deterioration characteristics. These pre-calculated current target values are stored and used during operation, eliminating the need for complex real-time adjustments while ensuring each bank operates within its safe current limits.
Solution Approach 2:
The patent changes the control parameter from a single system-level current target value to multiple bank-specific current target values. Each bank's current target value is adjusted based on parameters such as temperature and deterioration state. This parameter change enables individual bank current limit compliance while the system-level controller coordinates these individual targets to maintain overall aggregate current control.
3Measurement precision
If power conversion efficiency variations are accounted for, then accurate current control at the bank level is achieved, but measurement and control complexity increases
Solution Approach 1:
The system implements feedback by measuring the actual current at each bank and comparing it with the bank-specific current target value. The power conversion efficiency variations are accounted for by adjusting the current target values based on measured or estimated efficiency data. This feedback mechanism ensures accurate current control at the bank level while compensating for conversion efficiency variations without requiring overly complex measurement systems.
Data Source
AI summary
Provided is an energy storage unit 15A for an energy storage system, and the energy storage unit includes an energy storage bank 20 which is connected to a power conversion device 10, and a bank management device 50. The bank management device 50 either calculates, on the basis of a current target value Ino and a current measurement value Int of the energy storage bank 20, a current limit value Ilimit to limit an excess of a current I with respect to the current target value Ino, or calculates, on the basis of a power target value Pno and a power measurement value Pnt of the energy storage bank 20, a power limit value Plimit to limit an excess of power with respect to the power target value Pno.