Ablerex MSRT-Pro 1.5KVA User manual - page 19
36
5.
UPS Working Principle
5.1. UPS System Block Diagram
(fig 5.1)
Figure 5.1 above 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 power 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 & Output EMI Filter
The table below provide a summery guide to the UPS operating modes
against the Utility AC Power Source conditions
37
Utility
Conditions
UPS Operating Modes
LEDs Display
indications
Utility Normal
Rectifier convert AC to DC, battery
charging, Inverter convert DC to AC
and supply to loads with clean & stable
power.
,
,
LEDs
remain illuminated
Utility Abnormal
(under or over
voltage) / Absent
Rectifier and charger stop operating,
Battery discharge via DC~DC boost
circuit and supply to Inverter. Loads
continue to receive supply from
Inverter. Alarm buzzer beeps, UPS now
on battery mode.
LED off,
LED
illuminated
Utility
Abnormal/Absent,
Battery low voltage
Rectifier and charger stop operating,
Battery discharge via DC~DC boost
circuit and supply to Inverter. Alarm
buzzer beeps with quick & short
succession, indicating battery power
low and Inverter may stop supply soon.
LED off,
&
LED illuminated.
Paragraph 5.2 ~ 5.7 below provide detailed descriptions of the UPS operating
principle
5.2. When Utility is Normal
The working principle of the UPS under Utility normal condition is illustrated as
follows:
When Utility is normal, the AC source is rectified to DC, which fed into the inverter.
The charger will turn on automatically to charge batteries. The inverter revert the
DC to a cleaned and pure AC to supply energy to the load connected. The
,
,
LEDs illuminated
.
Fig 5.2