KR series
（
6
-
10kVA
）
user
’s manual
- 9 -
3.
Basic Principles and Structure
Summary
This chapter mainly introduces the principle and overall structure of KR Series (6&10kVA) UPS, including
the display meanings of panel indicator lights and definitions of external interface.
3.1 Working Principle of Single unit
3.1.1Working Principle Diagram
CHARGE
PFC AC/DC
SW
BATTERY
DC/DC
DC/AC
LOAD
AC INPUT
Fig.3.1-1 KR Series Working Principle Diagram
3.1.2 Working Principle
UPS KR(6-10)KVA is made up of PFC, AC/DC (Commercial power rectification and boost
circuit), DC/DC (battery voltage-boost circuit), DC/AC inverter, switch, charger and battery
group etc.
When commercial power is normal, through PFC, it can be boosted to stabilized DC supplied
for DC/AC inverter to output steady 220VAC and finish battery charge at the same time. When
commercial power is abnormal, through DC/DC, the battery voltage will be increased to
stabilized DC supplied for DC/AC inverter. Because of PFC and power-down fast-test
technique adopted, even when the commercial power voltage lows to limit 120V, the battery
group can still have no output current to assure battery longevity and be kept in energy-storage
status and if commercial abnormal battery voltage-boost will start up at once to assure steady
DC/AC output.
As shown in the Figure 3.1-1, the DC/AC inverter adopts half-bridge structure, DC/DC module
uses boost-circuit, PFC is active power-factor correction circuit and CHARGER is a kind of
complete isolation charger.
