Author: Site Editor Publish Time: 2024-08-15 Origin: Site
As the power system develops, the scale of the grid continues to expand, leading to higher demands for power communication. Batteries, as a critical component of the telecom power system, have a direct impact on the reliability of power communication. Conducting capacity testing through charge and discharge cycles is an essential method to maintain battery performance and extend battery life. According to the maintenance regulations for telecom power system, batteries require regular maintenance. Compared to methods such as terminal voltage measurement and internal resistance testing, capacity testing offers greater accuracy. Newly installed batteries require full-capacity discharge testing, followed by annual capacity discharge testing. For batteries in operation for four years, a semi-annual capacity testing is necessary. If a battery fails to achieve 80% of its rated capacity after three consecutive tests, it should be considered for replacement.
Currently, three common battery capacity testing schemes are widely applied in engineering: dummy load, DC/AC conversion, and DC/DC boosted voltage schemes.
The capacity testing device primarily consists of a high-frequency DC/DC battery pack boosted circuit module, a high-frequency DC/DC battery pack constant current charge module, contactors, and diodes. The system operates in three states: standby floating charge, capacity discharge, and constant current charge. These states form a complete operational cycle for capacity testing.
Standby Floating Charge State
In the floating charge state, the NC contactor K1 is closed, and the NO contactor KM opens. The battery is online, with the rectifier supplying power to both the battery pack and the load. In the event of an unexpected power outage, the battery pack can directly supply power to the load, ensuring uninterrupted power supply.
Figure 1: Battery Pack in Standby Floating Charge State
Capacity Discharge State
During capacity discharge, the NC contactor K1 opens, and the NO contactors KM and KC close. The high-frequency DC/DC battery pack boosted circuit works. The battery is boosted by the DC/DC circuit to a voltage slightly higher than the rectifier voltage, thus replacing the rectifier in supplying power to the load. Upon completion of the discharge, the system automatically switches to constant current charging, with the constant current charge circuit module working.
Figure 2: Battery Pack in Capacity Discharge State
Constant Current Charge State
After capacity discharge, the system automatically switches to constant current charging. The high-frequency DC/DC battery pack constant current charge circuit module works, automatically adjusting the charge current to the set value while using the original rectifier for constant current charging. As the battery voltage increases towards the end of the charging process, the charging current decreases. When the current drops below the device's set threshold, the system automatically ends the constant current charge process. The NC contactor K1 closes, stopping the high-frequency DC/DC battery pack constant current charge circuit module, and disconnecting KM and KC. The battery pack then returns to the standby floating charge state.
Figure 3: Battery Pack in Constant Current Charge State
The above describes the implementation of a capacity testing system based on DC/DC. The solution is widely adopted by industry manufacturers. For instance, DFUN has designed a comprehensive remote online capacity testing solution, achieving centralized control of dispersed sites remotely, which is time-saving, convenient, and reliable.
DFUN capacity testing solution, in addition to the capacity testing function, includes real-time battery monitoring and battery activation features, enabling remote, round-the-clock monitoring and maintenance of battery packs.
