Battery String Control for Converter Efficiency at Variable Load
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electric power storage systems with multiple storage battery strings and power converters, power conversion efficiency decreases as discharge or charge power decreases, leading to increased heat generation due to inefficient operation of power converters.
Innovation Solution
A storage battery control device dynamically adjusts the number of storage battery strings participating in discharge or charge based on power requirements to maintain optimal load factors for power converters, ensuring maximum power conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of storage battery strings performing charge or discharge is kept constant, then the system structure is simple, but power conversion efficiency decreases as discharge or charge power becomes smaller
Solution Approach 1:
The patent applies dynamics by making the number of storage battery strings performing charge or discharge variable rather than fixed. The control device dynamically adjusts this number based on the magnitude of discharge or charge power, allowing the system to adapt to changing power demands and maintain optimal power conversion efficiency across different operating conditions.
2Reliability
If a certain number of power converters operate regardless of power conversion efficiency, then the system maintains operational stability, but total heat generation amount increases
Solution Approach 1:
The patent applies parameter changes by adjusting the operational parameters of power converters based on power conversion efficiency. The control device monitors efficiency levels and selectively operates power converters to maintain stability while minimizing heat generation, particularly by avoiding operation of converters with low power conversion efficiency.
3Productivity
If power converters operate at low load factors, then more storage battery strings can be used, but power conversion efficiency decreases
Solution Approach 1:
The patent applies feedback by implementing a control device that monitors power conversion efficiency and uses this information to adjust the operation of power converters and storage battery strings. The control device receives feedback on efficiency levels and dynamically reconfigures the system to maintain optimal efficiency while meeting power demands.
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 maintains high power conversion efficiency across varying discharge and charge powers, reducing overall heat generation and cooling costs in the system.
Implementation Method 1
a plurality of power converters each provided between the storage battery string and the power line and configured to convert an input and output voltage of the storage battery string
Data Source
AI summary
A storage battery control device for controlling an electric power storage system includes a plurality of storage battery strings each including a plurality of storage batteries connected in series and connected by a power line, and a plurality of power converters each provided between the storage battery string and the power line and configured to convert an input and output voltage of the storage battery string. The number of the storage battery strings that perform discharge or charge is variably set according to a magnitude of discharge power or charge power of the electric power storage system. The number of the storage battery strings that perform discharge or charge is set such that a load factor of the power converter corresponding to the storage battery string that performs discharge or charge approaches a predetermined load factor at which power conversion efficiency of the power converter is maximized.