Flexible battery management

Batteries are vital UPS components that require careful management to deliver optimum performance. Charging circuits must be designed to eliminate ac ripple which, by increasing a battery's internal temperature reduces its operating life. If battery faults do occur they must be detected and signalled as early as possible.

In traditional UPS systems, batteries are charged directly from the rectifier output, with little or no protection from harmful ac and inverter ripple. By contrast, in the UPS Ltd. systems, the battery is charged from a separate battery charge circuit which delivers a ripple free DC charge current. The battery feeds back to the DC circuit through battery DC-Thyristors which are triggered only when the mains power is not available.

Most 3 phase UPS systems available today have advanced battery management algorithms that detect battery faults and trigger battery fault alarms, alerting the user to replace the battery. Typically, detection involves discharging the battery for a fixed time of around 2 - 3 minutes. The alarm is triggered if the battery voltage drops below a preset level during the discharge test.

The UPS Ltd. flexible battery management algorithm differs from other manufacturers' in how it detects a fault, and in how early it can warn the user. It has other benefits as well. Testing is intelligent, automatic and adjustable so that faults are detected and alarms generated as early as possible. The charge current is limited, and temperature compensation of the charging voltage is available as an option. There are also minimum and maximum battery voltage controls, and voltage limitation. The battery charge curve (IU) complies with DIN Standard 41 733.