Battery Cell Status Monitoring via Converter Signal Injection
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Solution Overview
Problem
Existing energy storage systems lack effective methods for monitoring their status, particularly during standby modes, which limits fault detection and accuracy in power transmission systems.
Innovation Solution
A method and control unit that utilize a power converter to inject an electrical signal into the energy storage system, measuring the response signal to determine its status, allowing monitoring even when the system is not charged or discharged, using a dedicated electrical signal with negligible impact on the power transmission system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the energy storage system is used for grid frequency support with short time windows, then the response time is improved, but the measurement precision deteriorates due to limited data points
Solution Approach 1:
The system performs status monitoring measurements before the actual grid frequency support operation begins. By conducting measurements during standby mode or before the short time window operation, the system accumulates sufficient measurement data points in advance, ensuring accurate status assessment without compromising the rapid response capability during actual grid support operations.
2Measurement precision
If the power converter generates a dedicated electrical signal for monitoring, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The power converter is designed to perform dual functions: it serves as both the power conversion device for grid frequency support and as the signal generation device for status monitoring. By utilizing the existing power converter's capability to generate electrical signals, the system avoids adding separate dedicated monitoring hardware, thereby improving measurement precision while minimizing the increase in overall device complexity.
3Reliability
If the energy storage system monitors status during standby mode, then the reliability is improved through early fault detection, but the loss of time for actual power transmission decreases
Solution Approach 1:
The system implements periodic status monitoring during standby mode at optimized intervals, allowing early fault detection while minimizing the time spent in monitoring mode. This periodic approach ensures the energy storage system is ready for rapid deployment when grid frequency support is needed, balancing reliability improvement with minimal impact on available response time.
Data Source
AI summary
A method for monitoring a status of an energy storage system connected to a power converter is disclosed. The energy storage system comprises a plurality of interconnected energy storage cells, and the power converter is configured to output power from the energy storage system to a power transmission system and to charge the energy storage system with power from the power transmission system. The method comprises generating, by the power converter, an electrical signal injected into the energy storage system, measuring a response signal generated in response to the injected electrical signal, and determining a status of the energy storage system based on the received response signal.