Battery String Voltage Adapters for STATCOM Energy Storage
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Solution Overview
Problem
In power transmission networks, STATCOM systems using electrochemical batteries face challenges with voltage variations due to aging cells and performance differences, leading to reduced efficiency and shortened service life, as well as the need for excessive redundancy to maintain capacity.
Innovation Solution
The implementation of battery string voltage adapter devices connected in series with each battery string, which can handle only a fraction of the total voltage, allows for optimized voltage equalization across all strings, preventing voltage differences and enabling faster disconnection of parallel strings, thus maximizing service life and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple battery strings are connected in parallel to provide required active power and duration, then the energy storage capacity is sufficient, but voltage differences arise due to performance variations of individual cells, reducing overall performance
Solution Approach 1:
The patent divides the battery system into independent string units, each equipped with its own DC/DC converter. This segmentation allows independent control and voltage regulation of each battery string, preventing voltage differences from affecting the entire system. Each converter manages its respective battery string's voltage and current independently, ensuring uniform performance across all parallel-connected strings.
Solution Approach 2:
The patent introduces DC/DC converter devices as intermediary components between the parallel battery strings and the STATCOM. These converters act as mediators that regulate voltage and current distribution, isolating individual battery strings from each other's performance variations. The intermediaries prevent voltage differences caused by cell aging or failures from propagating across the entire battery system.
2Productivity
If battery cells are bypassed when they fail or age, then operation can continue, but the charging voltage of the battery string is reduced, lowering overall performance
Solution Approach 1:
The patent dynamically adjusts the operating parameters (voltage and current) of each battery string through independent DC/DC converter control. When cells are bypassed or aged, the converter compensates by changing the electrical parameters to maintain optimal charging voltage and current levels. This allows the system to continue operating at full power capacity even with degraded or bypassed cells in individual strings.
3Reliability
If oversized batteries and additional battery strings are provided as capacity redundancy, then capacity requirements are met at all times, but the system complexity and cost increase
Solution Approach 1:
The patent implements dynamic voltage and current control through DC/DC converters for each battery string. This dynamic control allows the system to optimize power distribution in real-time, extracting maximum capacity from available batteries without requiring excessive redundancy. The adaptive control adjusts operating conditions to maintain reliability while utilizing the actual capacity of existing battery strings efficiently.
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to power networks, and in particular to a battery energy source arrangement 4 and voltage source converter system in such network. The battery energy source arrangement comprises a battery energy storage 2, which in turn comprises one or more parallel-connected battery strings 51,..., 5i,..., 5n, and connection means for connecting a voltage of battery strings 51,..., 5i,..., 5n to a load 1. The battery energy arrangement 4 comprises further battery string voltage adapter devices 71,..., 7i,..., 7n connected in series with a respective one of the one or more battery strings 51,..., 5i,..., 5n wherein the battery string voltage adapter devices 71,..., 7i,..., 7n are designed to handle only a fraction of the voltage handled by the battery strings 51,..., 5i,..., 5n.