10
| 2.0 System Description
2.0 System Description
Battery
SPD &
EMI/RFI
Filters
Rectifier/PFC
Dc-to-Dc
Converter
Inverter
Input
Output
G
Dynamic Bypass
L1
N
L1
N
G
Battery
Charger
Figure 1: Operating principle diagram
2.1 Surge Protection Devices (SPD) & EMI/RFI Filters
These UPS components provide surge protection and filter both electromagnetic interference (EMi) and radio frequency
interference (rFi). They minimize any surges or interference present in the mains line and keep the sensitive equipment
protected.
2.2 Rectifier/Power Factor Correction (PFC) Circuit
in normal operation, the rectifier/power factor correction (PFC) circuit converts mains ac power to regulated dc power for
use by the inverter while ensuring that the wave shape of the input current used by the UPS is near ideal. Extracting this
sine wave input current achieves two objectives:
•
The mains power is used as efficiently as possible by the UPS.
•
The amount of distortion reflected on the mains is reduced.
This results in cleaner power being available to other devices in the building not being protected by the UPS.
2.3 Inverter
in normal operation, the inverter utilizes the dc output of the power factor correction circuit and inverts it into precise,
regulated sine wave ac power. Upon a mains power failure, the inverter receives its required energy from the battery
through the dc-to-dc converter. in both modes of operation, the UPS inverter is on-line and continuously generating
clean, precise, regulated ac output power.
