Rechargeable Battery Testing via DC Bus Converter Control
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Solution Overview
Problem
Current methods for testing rechargeable batteries in power supply systems are time-consuming and require significant manual work, often necessitating batteries to be disconnected from the power supply system, which is not feasible in systems with unpredictable load variations.
Innovation Solution
A method and system that allows for testing a rechargeable battery connected to a DC bus within a power supply system, using a control system to set a test discharge current and end voltage, measuring the time to reach the end voltage while maintaining the battery current within a predetermined range, and aborting the test if a failure is detected, all while the battery is 'live' and supplying power to the load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the battery is disconnected from the power supply system for testing with a known constant load, then the measurement precision and reliability of battery state determination is improved, but the loss of time increases and the ease of operation deteriorates due to manual disconnection/reconnection requirements
Solution Approach 1:
The battery testing is performed continuously while the battery remains connected to the power supply system and continues to supply power to the load. The converter maintains power delivery to the load throughout the test by adjusting its output based on real-time battery voltage measurements, eliminating the need to disconnect the battery for testing.
Solution Approach 2:
The converter acts as an intermediary between the battery and the load during testing. It dynamically adjusts its operation to compensate for battery discharge, maintaining stable power delivery to the load while simultaneously enabling battery state measurement through controlled voltage comparison.
2Productivity
If multiple batteries are tested simultaneously at one location, then the productivity increases, but the reliability deteriorates because battery power must be available in case of grid power loss
Solution Approach 1:
Multiple batteries can be tested simultaneously while each continues to provide backup power capability to the system. The testing process does not interrupt the batteries' ability to supply power, maintaining system reliability while increasing testing throughput.
3Measurement precision
If manual disconnection and reconnection of batteries is performed during testing, then the measurement precision is improved through controlled test conditions, but the ease of operation worsens and human errors increase
Solution Approach 1:
The system automatically manages the testing process without requiring manual intervention for disconnection or reconnection of batteries. The control system autonomously monitors battery voltage, adjusts converter output, and determines test completion based on predetermined voltage thresholds.
4Ease of operation
If the battery is tested while connected to the power supply system with varying load, then the ease of operation improves by eliminating disconnection requirements, but the measurement precision deteriorates due to unpredictable load variations
Solution Approach 1:
The system continuously monitors battery voltage and uses this feedback to dynamically adjust the converter's output voltage. By comparing the battery voltage with the converter output voltage and measuring the resulting current, the system can accurately determine battery state even in the presence of varying load conditions.
Solution Approach 2:
The converter dynamically changes its output voltage parameter during testing based on real-time battery voltage measurements. This allows the system to maintain accurate battery state measurement while adapting to varying load conditions, as the converter voltage is continuously adjusted to optimize the measurement process.
Data Source
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AI summary
The present invention relates to a method of testing a rechargeable battery (4) connected to a DC bus (5) of a converter (11) of a power supply system (10) comprising a control system (12) for controlling power transfer between a power source (2), the rechargeable battery (4) and a load (3) connected to the DC bus (5). The method comprises the steps of - setting a test discharge current (I4d) for the rechargeable battery (4) to be used during the test and setting a test end voltage (Vend) for the rechargeable battery (4) to be used during the test; - at a first point in time (TO), starting a test run measuring a current (14) from the rechargeable battery (4) and a voltage (V4) over the rechargeable battery (4); - at a second point in time (Tend), when the measured battery voltage (V4) becomes equal to the test end voltage (Vend), terminating the test run; and - registering the time period elapsed between the first point in time (TO) and the second point in time (Tend) as a measure of the status of the rechargeable battery (4). During the test run, the method comprises the steps of: - bringing the converter (11) to deliver an output voltage (V11) which is lower than the battery voltage (V4), thereby causing the rechargeable battery (4) to supply power to the load (3); and - bringing the controller (11) to control at least one of the converter output voltage (VI 1) and the converter output current (111) so that the battery current (14) is kept within a predetermined range of the test discharge current (I4d).