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5. UPS System Block Diagram
Figure 4.1
Figure 4.1 illustrates the True On-Line Double Conversion architecture of the
UPS system. The major modules consist of:
1) An AC-to-DC power converter (rectifier) with PFC control circuit
2) A DC-to-AC high frequency inverter
3) An intelligent battery charger
4) A bank of stationary, maintenance-free batteries
5) A DC-to-DC push/pull converter control circuit
6) A static bypass loop
7) Input and output EMI filters
The table below provides a summary of the UPS operating modes under
various utility AC power source and battery conditions.
Utility Condition
UPS Operating Mode
LEDs
Normal
Working power starts after
approximately 5 seconds, LEDs on the
panel will blink and fans will start. Press
the ON button
for 1-5 seconds. The
UPS starts up normally.
、
、
and
LEDs
remain lit
Abnormal (under or
over voltage or
absent)
Rectifier and charger stop operating.
Battery discharges via DC-DC boost
circuit and supplies Inverter. Loads
continue to receive supply from
Inverter. Alarm buzzer beeps. UPS now
in battery mode.
LED off,
LED
illuminated
Utility abnormal or
absent, or battery
voltage low
Rectifier and charger stop operating.
Battery discharges via DC-DC boost
circuit and supplies Inverter. Alarm
buzzer beeps quickly, indicating battery
power low and Inverter may stop
supplying soon.
LED off,
and
LEDs illuminated
